LIFTING EQUIPMENTS Lifting equipment, also known as lifting gear, is a general term for any equipment that can be used for lifting loads. This includes jacks, block and tackle, hoists, rotating screws, gantries, A frames, gin poles, shear legs, sheerleg, windlasses, lifting harnesses, fork lifts, hydraulic lifting pads, air lift bags, and cranes.
JACK
A jack is a mechanical device used as a lifting device to lift heavy loads or apply great forces. Jacks employ a screw thread or hydraulic cylinder to apply very high linear forces. A mechanical jack is a device which lifts heavy equipment. The most common form is a car jack, floor jack or garage jack which lifts vehicles so that maintenance can be performed. More powerful jacks use hydraulic power to provide more lift over greater distances. Mechanical jacks are usually rated for a maximum lifting capacity ( for example, 1.5 tons or 3 tons).
BLOCK AND TACKLE A block and tackle is a system of two or more pulleys with a rope or cable threaded between them, usually used to lift or pull heavy loads. 1
The pulleys are assembled to form blocks and then blocks are paired so that one is fixed and one moves with the load. The rope is threaded, or reeved, through the pulleys to provide mechanical advantage that amplifies that force applied to the rope. A block is a set of pulleys or "sheaves" mounted on a single axle. The assembly of two blocks with a rope threaded through the pulleys is called tackle. A block and tackle system amplifies the tension force in the rope to lift heavy loads. They are common on boats and sailing ships, where tasks are often performed manually.
HOISTS A hoist is a device used for lifting or lowering a load by means of a drum or lift-wheel around which rope or chain wraps. It may be manually operated, electrically or pneumatically driven and may use chain, fibre or wire rope as its lifting medium. The load is attached to the hoist by means of a lifting hook.
Types of hoist The basic hoist has two important characteristics to define it: lifting medium and power type. The lifting medium is either wire rope, wrapped around a drum, or load- chain, raised by a pulley with a special profile to engage the chain. The power can be provided 2
by different means. Common means are hydraulics, electrical and air driven motors. Both the wire rope hoists and chain hoists have been in common use.
CRANE A crane is a type of machine, generally equipped with a hoist, wire ropes or chains, and sheaves, that can be used both to lift and lower materials and to move them horizontally. it is mainly used for lifting heavy things and transporting them to other places. It uses one ore more simple machine to create mechanical advantage and thus move loads beyond the normal capability of a human. Cranes are commonly employed in a transport industry for the loading and unloading of freight, in the construction industry for the movement of materials and in manufacturing industry for the assembling of heavy equipment.
3
06-May-14
1
Material-handling equipment is equipment that relate to the movement, storage, control and protection of materials, goods and products throughout the process of manufacturing, distribution, consumption and disposal. Material handling equipment is the mechanical equipment involved in the complete system.Material handling equipment is generally separated into four main categories: storage and handling equipment, engineered systems, industrial trucks, and bulk material handling. 2
Material handling equipment is used to increase output, control costs, and maximize productivity. There are several ways to determine if the material-handling equipment is achieving peak efficiency. These include capturing all relevant data related to the warehouse’s operation, measuring how many times an item is “touched” from the time it is ordered until it leaves the building, making sure you are using the proper picking technology, and keeping system downtime to a minimum. A special analytical data-set known as Stockkeeping units (SKUs) has been devised to aid analysis of materials handling, which is obviously less efficient when a material asset is handled any more than a minimally necessary number of times.
3
4
Engineered systems Equipment and utensils used for processing or otherwise handling edible product or ingredients must be of such material and construction to facilitate thorough cleaning and to ensure that their use will not cause the adulteration of product during processing, handling, or storage. Equipment and utensils must be maintained in sanitary condition so as not to adulterate or contaminate product. 5
Storage and handling equipment Storage and handling equipment is a category within the material-handling industry. The equipment that falls under this description is usually non-automated storage equipment. Products such as pallet racking, shelving and carts, among others, belong to storage and handling. Many of these products are often referred to as "catalog" items because they generally have globally accepted standards and are often sold as stock materials out of Material handling catalogs.
Industrial trucks Industrial trucks usually refer to operator driven motorized warehouse vehicles, powered manually, by gasoline, propane or electrically. Industrial trucks assist the material-handling system with versatility; they can go where engineered systems cannot. Forklift trucks are the most common example of industrial trucks but certainly aren't the extent of the category. Tow tractors and stock chasers are additional examples of industrial trucks. Their greatest advantage lies in the wide range of attachments available; these increase the truck ability to handle various types and shapes of material. 6
1
06-May-14
Bulk material handling Bulk material-handling equipment is used to move and store bulk materials such as ore, liquids, and cereals. This equipment is often seen on farms, mines, shipyards and refineries.
On-rails transfer cart On-rails transfer cart is a kind of material-handling equipment. It moves on the rails and can transfer heavy cargoes or equipment with the weight 1-300t between the workshops or warehouses in the factory. It is widely used in the line of metallurgy, coal, heavy manufacturing, automotive assembly, etc. Its power can be AC or DC. DC Power has rail transmit power and battery power, while AC power includes cable power and slippery touch line power. In addition, there is the manual rail transfer cart or towed rail transfer cart, also called motorized transfer trolley.
7
Conveyors Conveyors are another form of material handling. Conveyors can be used in a multitude of ways from warehouses to airport baggage handling systems. Some types of conveyors are unibilt, power and free, chain, towline and roller conveyor. Cantilevered crane loading platform Cantilevered crane loading platforms are temporary platforms attached to the face of multistorey buildings or structures to allow materials and equipment to be directly loaded on or shifted off floor levels by cranes during construction or demolition. They may be fixed or rolling and a variety of designs are used including fully fabricated and demountable types. The platforms are supported on needles (cantilevered beams) anchored to the supporting structure.
8
These principles are guidelines for the application of sound judgment. Some principles are in conflict with others, so only the situation being designed will determine what is correct. The principles will be a good checklist for improvement opportunities.
9
1. Planning Principle All material handling and storage activities need to be planned to obtain maximum overall operating efficiency. Material handling planning considers every move, every storage need and any delay in order to minimize production costs. 2. System Principle The system concept is that all material handling equipment should work together so that everything fits. The system principle integrates as many steps in the process as possible into a single system from the vendor through your plant and out to your customers. It is to integrate as many handling activities as is practical into a coordinated system of operations, covering vendor, receiving, storage, production, inspection, packaging, warehousing, shipping, transportation and customer. 11
10
An example will be a oil company purchased plastic bottles from an outside manufacturer. The bottles were packaged in a carton of 12 with separators in between. These cartons were placed on a pallet and shipped out to the company’s oil bottling plant. In the plant, the bottles were dumped onto a filing line and filled with oil. The empty cartons was conveyed to the packout end of the filing line and repacked with 12 bottles, closed, stacked on a pallet and shipped to the customer. 3. Material Flow Principle It is to provide an operation sequence and equipment layout optimizing material flow. 4. Simplification Principle Using Cost Reduction Formula to simplify handling (Eliminate, combine and reduce unnecessary movement and/or equipment). 12
2
06-May-14
5. Gravity Principle
8. Mechanization Principle
There are many ways to make use of gravity to move materials between workstations. Thus, utilize gravity to move material wherever possible.
It is to add power to eliminate manual moving. Mechanization implies the use of mechanical tools to aid in the movement of material.
6. Space Utilization Principle
9. Automation Principle
It is to make optimum utilization of the cubic capacity of the warehouse. Racks, mezzanines and overhead conveyors are a few of the material handling equipments that maximize space utilization.
Automatic storage and retrieval systems place material into storage racks automatically and remove it when needed. Many machines are automatic because material handling equipment loads and unloads the machine. Automation is the way of the future, thus even users of the manual system must consider when it can be justified. Provide automation to include production, handling and storage functions.
7. Unit Size Principle Strength, durability, versatility, weight, size, cost and ease of use must all be considered when choosing a unit load. It is to increase the quantity, size, or weight of unit loads or flow rate.
10. Equipment Selection Principle In selecting handling equipment consider all aspects of the material being handled – the movement and the method to be used.
13
14
11. Standardization Principle
13. Dead Weight Principle
It is to standardize handling methods as well as types and sizes of handling equipment. Cost of material handling systems can be grouped into two categories: the cost of ownership of the system (includes the initial purchase price and the subsequent maintenance costs) and the cost of operation of the system (includes cost of training personnel to use the system safely, energy cost and other direct and indirect costs associated with the use of the system). An example will be choosing a material handling equipment and stay with that brand, type and size because spare parts inventory, maintenance and operation of this equipment will be most cost efficient.
Do not buy equipment that is bigger than necessary. Tare weight refers to the weight of the packaging material. Products are packaged to prevent damage while moving. However, packaging is expensive and it costs as much as the product to ship this tare weight. Thus, the goal is to reduce the tare weight and save money. 14. Utilization Principle
12. Adaptability Principle
Material handling equipment and operators should be used fully. Identifying the work required, the number of times per day and the time required per move will help manage the workload of both labour and equipment. Plan for optimum utilization of handling equipment and manpower.
Use methods and equipment that can best perform a variety of tasks and applications where special purpose equipment is not justified. Examples will be the purchasing of standard size pallets that will handle a range of parts and purchasing of storage equipments that can store a wide variety of products. In this way, change will be less costly.
15. Maintenance Principle Material handling equipment must be maintained. Preventive maintenance (periodic and planned) is cheaper than emergency maintenance. Hence, a preventive maintenance program including schedules must be developed for each piece of material handling equipment.
15
Pallets, storage facilities need to be repair. Missing slats on pallets can cause product damage and safety problems. Thus, plan for preventive maintenance and scheduled repairs of all handling equipments. 16. Obsolescence Principle As equipment wears out, good maintenance records will help identify worn-out equipments. Replace obsolete handling methods and equipment when more efficient methods or equipment will improve operations. 17. Control Principle Materials are costly and material handling systems can be a part of the inventory control system. With the aid of technology (e.g. conveyor, RFID, barcode), quality inspection, inventory control and item tracking can be incorporated into the material handling systems. It will reduce or eliminate the need to count or track the material physically. A good material handling system allows a tremendous savings in operation time and significant improved costs, accuracy and reliability. Hence, use material handling activities to improve control of production inventory and order handling.
17
16
18. Capacity Principle Use handling equipment to help achieve desired production capacity. 19. Performance Principle It is to determine effectiveness of handling performance in terms of expense per unit handled. Material handling labour moves material and a measurement of output could be units of materials moved. Input is labour hours. Therefore, productivity can be improved by increasing the units of material moved or reducing the labour hours. Performance of material handling can also be calculated by ratios: Percent of Material Handling = (material handling hours)/(total labour hours) Performance includes a lot more than labour. Segregating material handling cost from total operation costs would result in a better ratio. 20. Safety Principle Manual handling is probably the most dangerous method of material handling. Material handling equipment can also be a source of safety problems, so safety methods, procedures and training must be part of any material handling plan. It is management responsibility to provide a safe work environment. Safety considerations must be a major factor in selecting material handling equipment. Therefore, it is important to provide suitable methods and equipment for safe handling. 18
3
HOISTS
0
Hoists A hoist is a device used for lifting or lowering a load by means of a drum or lift-wheel around which rope or chain wraps. It may be manually operated, electrically or pneumatically driven and may use chain, fiber or wire rope as its lifting medium. The load is attached to the hoist by means of a lifting hook.
TYPES OF HOISTS The basic hoist has two important characteristics to define it: Lifting medium and power type. The lifting medium is either wire rope, wrapped around a drum, or load-chain, raised by a pulley with a special profile to engage the chain. The power can be provided by different means. Common means are hydraulics, electrical and air driven motors. Both the wire rope hoist and chain hoist have been in common use since the 1800s. However; Mass production of an electric hoist did not start until the early 1900s and was first adapted by Germany. A hoist can be built as one integral-package unit, designed for cost-effective purchasing and moderate use, or it can be built as a built-up custom unit, designed for durability and performance. The built-up hoist will be much more expensive, but will also be easier to repair and more durable. Package units were once regarded as being designed for light to moderate usage, but since the 60s this has changed. Built-up units are designed for heavy to severe service, but over the years that market has decreased in size since the advent of the more durable packaged hoist. A machine shop or fabricating shop will use an integral-package hoist, while a Steel Mill or NASA would use a builtup unit to meet durability, performance, and reparability requirements. NASA has also seen a change in the use of package hoists. The NASA Astronaut training pool, for example, utilizes cranes with packaged hoists.
Wire Rope Hoist or Chain Hoist
Builder's hoist, with small gasolineengine
More commonly used hoist in today's worldwide market is an electrically powered hoist. These are either the chain type or the wire rope type. Nowadays many hoists are package hoists, built as one unit in a single housing, generally designed for ten-year life, but the life calculation is based on an industry standard when calculating actual life. See the Hoists Manufacturers Institute site[1] for true life calculation which is based on load and hours used. In today's modern world for the North American market there are a few governing bodies for the industry. The Overhead Alliance is a group that represents Crane Manufacturers Association of America (CMAA), Shanghai WANBO Hoisting Machinery(VANBON), Hoist Manufacturers Institute (HMI), and Monorail Manufacturers Association (MMA). These product counsels of the Material
Handling Industry of America have joined forces to create promotional materials to raise the awareness of the benefits to overhead lifting. The members of this group are marketing representatives of the member companies. Common small portable hoists are of two main types, the chain hoist or chain block and the wire rope or cable type. Chain hoists may have a lever to actuate the hoist or have a loop of operating chain that one pulls through the block (known traditionally as a chain fall) which then activates the block to take up the main lifting chain.
A ratchet lever hoist (come-along).
A hand powered hoist with a ratchet wheel is known as a "ratchet lever hoist" or, colloquially, a "come-along". The original hoist of this type was developed by Abraham madam of Deep Creek, Colorado about 1919, and later commercialized by his son, Felber Masada, about 1946. It has been copied by many manufacturers in recent decades. A similar heavy duty unit with a combination chain and cable became available in 1935 that was used by railroads, but lacked the success of the cable-only type units.[2] Ratchet lever hoists have the advantage that they can usually be operated in any orientation, for pulling, lifting or binding. Chain block type hoists are usually suitable only for vertical lifting.
For a given rated load wire rope is lighter in weight per unit length but overall length is limited by the drum diameter that the cable must be wound onto. The lift chain of a chain hoist is far larger than the lift wheel over which chain may function. Therefore, a high-performance chain hoist may be of significantly smaller physical size than a wire rope hoist rated at the same working load.
A differential pulley chain hoist
Both systems fail over time through fatigue fractures if operated repeatedly at loads more than a small percentage of their tensile breaking strength. Hoists are often designed with internal clutches to limit operating loads below this threshold. Within such limits wire rope rusts from the inside outward while chain links are markedly reduced in cross section through wear on the inner surfaces. Regular lubrication of both tensile systems is recommended to reduce frequency of replacement. High speed lifting, greater than about 60 feet per minute (18.3 m/min), requires wire rope wound on a drum, because chain over a pocket wheel generates fatigue-inducing resonance for long lifts. The unloaded wire rope of small hand-powered hoists often exhibits a snarled "set", making the use of a chain hoist in this application less frustrating, but heavier. In addition, if the wire in a wire hoist fails, it can whip and cause injury, while a chain will simply break. "Chain hoist" also describes a hoist using a differential pulley system, in which a compound pulley with two different radii and teeth engage an endless chain, allowing the exerted force to be multiplied according to the ratio of the radii.
Construction hoists
A hoist on the Trump International Hotel & Tower-Chicago Also known as a Man-Lift, Buckhoist, temporary elevator, builder hoist, passenger hoist or construction elevator, this type of hoist is commonly used on large scale construction projects, such as high-rise buildings or major hospitals.[3] There are many other uses for the construction elevator. Many other industries use the buckhoist for full-time operations, the purpose being to carry personnel, materials, and equipment quickly between the ground and higher floors, or between floors in the middle of a structure. There are three types: Utility to move material, personnel to move personnel, and dual-rated, which can do both.[4] The construction hoist is made up of either one or two cars (cages) which travel vertically along stacked mast tower sections. The mast sections are attached to the structure or building every 25 feet (7.62 m) for added stability. For precisely controlled travel along the mast sections, modern construction hoists use a motorized rack-and-pinion system that climbs the mast sections at various speeds. While hoists have been predominantly produced in Europe and the United States, China is emerging as a manufacturer of hoists to be used in Asia. In the United States and abroad, General Contractors and various other industrial markets rent or lease hoists for a specific projects. Rental or leasing companies provide erection, dismantling, and repair services to their hoists to provide General Contractors with turnkey services. Also, the rental and leasing companies can provide parts and service for the elevators that are under contract.
Mine hoists
A water-powered mine hoist used for raising ore from De re metallica. In underground mining a hoist or winder[5] is used to raise and lower conveyances within the mine shaft. Human, animal and water power were used to power the mine hoists documented in Agricola's De Re Metallica, published in 1556. Stationary steam engines were commonly used to power mine hoists through the 19th century and into the 20th, as at the Quincy Mine, where a 4-cylinder cross-compound corliss engine was used.[6]Modern hoists are powered using electric motors, historically with direct current drives utilizing solid-state converters (thyristors); however, modern large hoists use alternating current drives that are variable-frequencycontrolled.[5] There are three principal types of hoists used in mining applications, Drum Hoists, Friction (or Kope) hoists and Blair multi-rope hoists.
COMPONENTS OF HOISTS
Bridge Drive
Chain
Button
Chain Sprocket
Conductor Bar
Friction Clutch
Hook
Failsafe Brake
Hoist motor
Mendel Brake
Push –button
Sheave
Travel Limit Switch
Rigging Parts
Small Inverter
Vacuum Pads
VDF
Wire Rope
PARTS OF HOISTING EQUIPMENT It has already been stated that most of the hoisting equipment utilize common type of parts like chain, wire rope, chain or rope drums, pulleys, lifting attachments like hook, grabs etc. A brief discussion of these parts has been included in this section. However, the parts used in elevators are different, and have been discussed under the chapter on elevators. Similarly other specific parts associated with individual equipment have been discussed along with discussion of the respective equipment.
Chain and Chain Sprockets The types of chains used in hoisting equipment are (1) welded load chains and (ii) roller chains. Welded chains are used in low capacity hoisting machines (hoists, winches, hand operated cranes etc.) as the main lifting appliance as slings for suspending load from the hook or other lifting attachments. Welded calibrated chains are employed as hand operated chain for driving the traction wheels of hoists and hand operated overhead cranes (hoists and cranes are referred in sections 8.2 and 8.5 respectively). Welded chains are manufactured by joining one gap of individual chain links by hammer hot forging or by resistance welding of two half links. Resistance welded chains are more accurate and have increased strength. Disadvantages of the welded chain are their (i) heavy weight,
(ii) Susceptibility to jerks and overloads, (iii) heavy wear of the links, (iv) low safe speed of movement, (v) sudden failure without previous indication etc. On the other hand the advantages are their (i) flexibility in all directions, (ii) possibility of using small sized pulleys and drums, (iii) simple design and manufacturing process etc. The diameter of welded chain pulleys or drums are, however, should not be less than 20d, where d is the diameter of rod of each link.
Steel Wire Ropes and Drums Steel wire ropes are extensively used as a flexible lifting media in hoisting machinery. The major advantages of using steel wire ropes compared to chains are the following: (i) (ii) (iii)
(iv)
Lighter weight Flexibility of operation. Load can be lifted with connecting ropes making large angles with the vertical. Greater reliability of operation. Rope does not give away suddenly without any notice. The outer layers of the wire ropes undergo intensive wear and always break from outside. This gives prior warning for changing of the rope before complete failure. Wire rope is less susceptible to damages from jerks which are very common in hoisting operations. Wire ropes are made from steel wires, cold drawn and specially heat treated to an ultimate strength of 130 to 200 kg/mm2. Number of steel wires is twisted to make into a strand and number
of such strands is twisted over a core made of hemp, asbestos or wire of softer steel. Constructional details and breaking strength of steel wire ropes are specified in Indian Standard IS: 2266:1989, "Steel Wire Ropes for General Engineering Purposes-Specification". Cross section of a few selected wire ropes as per above is shown in Fig. 8.1.4.
Rope drums The purpose of a rope drum is to store length of wire rope on the face of the drum. Wire rope under tension from the weight of the load being lifted, can be coiled in by rotating the drum, and uncoiled by rotating the drum in opposite direction. Life of wire rope depends on the —D/d ratio and number of bends the rope has to undergo. D = drum diameter and d = diameter of the rope. The diameter d of rope is measured over a pair of opposite strands. The minimum permissible diameter of a rope drum or pulley is found from the relation: D>e1 e2 d Where, D = drum/pulley diameter measured over the bottom of the rope groove, mm d = rope diameter, mm
el = factor depending on the type of hoisting equipment and its service e2 = factor depending on rope construction. It is generally taken to be lfor cross lay and 0.9 for parallel lay.
Pulleys and Pulley Systems Pulleys can be of two designs—fixed and movable. Fixed pulleys having fixed axles are also called guiding pulleys as they help to change the direction of the flexible element (wire rope in the case of hoisting equipment). Use of each pulley increases the pull or effort on the rope, because of the resistance offered by the pulleys. Pulley resistance arises out of resistance of the rope to bending over the pulley and frictional resistance in the pulley bearings.
Moveable pulleys have movable axles to which either a load or effort is applied. Accordingly, there are two applications of movable pulleys, firstly for a gain in force and secondly for a gain in speed. The two applications of movable pulley have been shown in Fig. 8.1.5. For the figure shown in 8.1.5(a), the distance 'S' travelled by the point in rope where effort 'Z' is applied is equal to twice the height , to which the load 'Q' is raised. S = 2h and c = 2v. where c = speed rope and v = speed of load. The effort Z = E So, where E is called pulley factor of resistance. We have Z + So= Q and 2Z0 = Q.
Arresting Gears and Brakes In hoisting equipment, use of arresting gears or brakes is of paramount importance to prevent the raised load from getting lowered of its own weight, when the raising effort is withdrawn. Arresting gear is used to hold the load lifted by winches. The common arresting gears are (a) Pawl and ratchet mechanism i.e. ratchet gearing. This comprises of ratchet wheel and a pawl. The ratchet teeth can be arranged external or internal to the wheel. The teeth are so designed that the ratchet wheel runs free over the pawl when the load is being raised, but the pawl gets engaged with ratchet tooth when the ratchet wheel tries to rotate in opposite direction (lowering direction of load). During lowering of load, the pawl has to be kept deliberately away from ratchet path. (b) Roller ratchet or roller clutch is used as an arresting gear in combination with a brake.
Brakes are used for dual purpose of holding the suspended load at rest and for controlling the speed of lowering of load. Some of these brakes are to be operated while some are automatic. Operated brakes include shoe, band, cone, disk brakes etc.. Centrifugal brakes and brakes applied by weight of the load are the automatic types. Actuation of the operated brakes may be through pulling a handle or by pressing a pedal which are termed as mechanical brakes. Actuation can be through energizing magnet by AC or DC electricity (electromagnetic brakes) or may be by hydraulic means (electro-hydraulic thrust or brakes). The electromagnetic brakes and electrohydraulic thrust or brakes can be used as controlled brakes. Moreover, these brakes can also be used as fail safe device. Normally these are in open condition (brake is not engaged), but actuates when the power fails. Fig. 8.1.8 shows line diagrams of an electromagnetic brake and a thrust or brake.
Load Handling Attachments The common attachments used with various hoisting equipment are (A) hooks, (B) grabs of different types, (C) grab buckets for bulk load, (D) ladles for liquid materials, (E) electro magnets etc. These different attachments are discussed below:
(A) Hooks: The common method of lifting unit load by hoisting equipment is to sling the load by chain or rope and suspended it from the hook of the hoisting equipment. To facilitate handling of loads by hook, many manufactured goods or packages are provided with hooking facilities (rings, bails, holes etc. through which a hook may be readily introduced). After forging and machining operations, the hooks are annealed. The inner diameter of the hook should be sufficient to accommodate two strands of chain or wire rope. The load is always carried by four elements sling with two loops. The body of the hook is generally of trapezoidal section while it ends at the top in a round section working under tension. The top part of the shank is threaded for suspension from a crosspiece. Hooks are mandatorily to be tested under testing load and got certified before use. Some of the common types of hooks are as follows: (i) Standard hooks are the most commonly used hooks which have a single curved horn. (ii) (iii)
Rarnshorn hooks have two horns like that of a ram. Saddles of each horn are smaller than the saddle of a standard hook of same capacity. Solid triangular eye hooks are used in cranes of capacity over 100 tons. The disadvantage of these hooks is that the sling rope must be passed through the eye first, before they are attached to the load.
(iv)
Hinged triangular hooks are made up of a few components, and are much simpler to produce. Fig. 8.1.9 shows line diagrams of standard, ransom and hinged triangular hooks.
(B) Grabs: For quick suspension and release of typical types of loads, certain specific grabs are used. The special performance requirements of these grabs are: Conformation to the shape and properties of the load. (i) (ii) Quick grabbing and releasing. (iii) Adequate strength and reliability. (iv) Safety to men and loads. (v) Convenience of use. (vi) Low weight. Some of the common grabs in use are briefed below: (a) Carrier beams are employed to lift long and heavy loads. Fig. 8.1.11 shows a carrier beam with adjustable shackles from which the loads are suspended.
(b) Crane grabs and clamps of different styles are used for handling different types of load. (i) carrier type grabs are used for carrying short or long shafts. (ii) Clamps are used to grip sheet or plate type loads. Following Fig. 8.1.12 exhibits a few types of grabs and clamps
(b) Self-closing tongs are used for automatic grabbing of different shapes. The tongs are made self-closing to avoid manual intervention during grabbing. Fig. 8.1.13 shows a few self-closing tongs.
(C) Grabbiug attachments are used for lifting loose/bulk materials by means of a crane and transferring them. There are basically two types of these grabbing attachments for loose materials: (a) Tubs: These are box type structures made from steel sheets. The tubs are provided with doors at the bottom or sides which can he opened by pulling a rope from the crane for automatic dumping of the contents inside the tub. However, these tubs have to be filled up manually or by using some other materials handling equipment. The tubs are provided with bails for suspend-ing them from a crane hook. (b) Grab buckets: These are specially designed bucket attachments which scoop loose materials and dump them mechanically through manipulation of ropes from the crane. Grab buckets are used for handling large amount of loose materials through cranes. The bucket essentially consists of two clam shell like scoops with rounded bottoms which are hung by four rods from a top cross-member. The inner ends of the scoops are also hung from another movable cross-member. All the joints are provided with pins for pivot action. The top and bottom crossmembers are suspended through ropes from a crane.
(D) Ladles: Ladles made from plate steel and having a refractory lining are used for carrying hot liquid metal. Small ladles or crucibles may be handled manually. But large ladles are conveyed in ladle cars, but more commonly by cranes. A crane ladle essentially has a bail. Smaller ladles may be tilted (for pouring) manually and medium size ladles by hand wheel actuated mechanism. However, large ladles are tilted by special devices actuated from the crane itself. (F.) Electromagnets: Electro lifting magnets are used to handle magnetic materials of differend shapes and sizes like ingots, steel structural (beams, rails etc.), plates, scraps, pigs, metal chips etc. The particular advantage of using magnets for lifting is that it does not need any time for fixing or releasing of the load. It is also very convenient for stacking of such items to a large height without labour. However, electromagnet has the risk of materials falling off in the event of a power failure. The other disadvantage is the large weight of the magnet itself which reduces the capacity of the hoisting crane. Electromagnets are particularly popular in steel plants, fabrication yards and scrap yards. The magnets are generally hung from the crane hook through chain slings.
LOAD HANDLING ATTACHMENTS The common attachments used with various hoisting equipment are (A) Hooks (B) Grabs of different types (C) Grab buckets for bulk load (D) Ladles for liquid materials (E) Electro magnets etc. These different attachments are discussed below: (A) HOOKS: The common method of lifting unit load by hoisting equipment is to sling the load by chain or rope and suspended it from the hook of the hoisting equipment. To facilitate handling of loads by hook, many manufactured goods or packages are provided with hooking facilities (rings, bails, holes etc. through which a hook may be readily introduced). After forging and machining operations, the hooks are annealed. The inner diameter of the hook should be sufficient to accommodate two strands of chain or wire rope. The load is always carried by four elements sling with two loops. The body of the hook is generally of trapezoidal section while it ends at the top in a round section working under tension. The top part of the shank is threaded for suspension from a crosspiece. Hooks are mandatorily to be tested under testing load and got certified before use. Open hooks may be used only in special cases where it is ensured that no hazard to personnel, nearby objects or materials will be created during the lifting operation. The load must always be set squarely within the hook bowl. The hook’s safety latch must be of suffi cient strength and laterally supported to be able to fully withstand the loading and operating stresses. Some of the common types of hooks are as follows: 1
(i) Standard hooks are the most commonly used hooks which have a single curved horn. (ii) Ramshorn hooks have two horns like that of a ram. Saddles of each horn is smaller than the saddle of a standard hook of same capacity. Ramshorn hooks are designed specifically for lifting heavy loads and are commonly used throughout the marine lifting industry. The twin hook design makes it ideal for use with two webbing slingsthis design assists greatly with load distribution, prevents any lifting sling damage and avoid chocking at the hook. Ramshorn hooks are commonly used with heavy lifting cranes and are found extensively in containers and shipping ports. (iii) Solid triangular eye hooks are used in cranes of capacity over 100 tons. The disadvantage of these hooks is that the sling rope must be passed through the eye first, before they are attached to the load. (iv) Hinged triangular hooks are made up of a few components, and are much simpler to produce.
2
Ramshorn Hook
Hinged triangular hook
(B) GRABS: For quick suspension and release of typical types of loads, certain specific grabs are used. The special performance requirements of these grabs are: quick grabbing and releasing. conformation to the shape and properties of the load. adequate strength and reliability. safety to men and loads. 3
convenience of use. low weight. Some of the common grabs in use are briefed below: (a) Carrier beams are employed to lift long and heavy loads. Figure shows a carrier beam with adjustable shackles from which the loads are suspended.
(b) Crane grabs and clamps of different styles are used for handling different types of load. (i) carrier type grabs are used for carrying short or long shafts (ii) Clamps are used to gripsheet or plate type loads.
4
c) self closing tongs are used for automatic grabbing of different shapes. The tongs are made self closing to avoid manual intervention during grabbing. Figure shows a few self closing tongs.
Figures of grabs
(C) CLAMPS: Clamps are used for lifting plates and sheets, profiled products and pipes. The holding force is typically based on the grip between the clamp’s toothed eccentric cam and the 5
surface of the lifted item. Parts of lifting clamps 1. Body 2. Lifting eye 3. Cam segment 4. Safety latch 5. Spring 6. Cam segment shaft 7. Lifting eye shaft 8. Pivot
6
Lifting clamps must show the following markings:
working load limit minimum and maximum thickness or width of lifted items production/serial number name of manufacturer/supplier CE marking
When using clamps
7
Check that the clamp is in order and suitable for use and that the surface hardness of the lifted item does not exceed the maximum surface hardness permitted for the clamp. The clamp must be compatible with the lifting appliance’s hook and, if necessary, a chain sling with a sufficiently large ring must be used. Do not exceed the working load limit. Check that the contact surface is free of scale, paint, dirt, ice, grease or other substances that may weaken the holding capacity. Always observe the designated loading direction of the clamp. The clamp must be positioned to follow the lifting direction of the sling. Pendular motion of the fastened item must be prevented, as this can damage the clamp’s cam teeth. When lifting long plates or sheets, two or more clamps and lifting booms should be used. Lift only one plate or sheet at a time when vertical lifting with a plate/sheet lifter. At least two pairs of horizontal clamps should be normally used. Do not exceed the maximum sling angle specified by the clamp manufacturer. When turning or moving, always keep the end of the plate/sheet or lifted load towards you. Lifting above personnel is strictly forbidden. Wear of the contact surfaces of the lifting clamp’s cam segment and counter jaw must be monitored and inspection intervals shortened as necessary. If the clamp has undergone repair, its operation must be checked by means of a test lift.
8
0123345628829 58 13 28 142
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
0124561782628092 7 7 6159 2 805 7475947015206829 652 012 7 6159 2 4 17610958 29 01245029759859 0958 90507812 7 6159 246585 9050278 228 2800124578405677050268287280 7 6159 255670620 122265509 45 059050 4 1958 2622 4 19
!620122265509 655670 4 1 " #$%&'()*+,-.+/0%$'12),34$2'5+,6$7+2 12!2085 894 0127820228012!620812296550958 012 98 6829 50 0124782 :72012620122265509012205 85 15 078 228 280 25258 524 25617015206829 4802 858 2028 78 8270129 7 2012 8 29659975 270169529 ;820124 926272 0124502975 7 6159 2 94012 62012226550958 0958 29 7000120129 7 6159 2417610958 90 012 45029750012 98 682955670205 815 02450612 7010150620 122265509097 25450612 024 " <=2$)>$2
0131456161789 3 6813 31 633581 81 3 53 633 8 58 9 68 8 7 6173
8 3 353 63 8 561
53 63 3 8 13 18 534 59 3 36 31 853561 6 98 9 3 53 636 3 7 85
33 8 6 31 98 8 9 3 8137 8181 48 9 3 89 3
61811 6816 3 !"# !66 3 7
618561753 6381 7 8181 48 8 81 48 81
66178858 9 3 81 48 31 53 63 8318 81 48
998 81 38176 3 7 88566 3 7
61 8396 8856 393 8 617 931 81 313 8 81 998 6171 3 637 1161781 3 8$96617853 63 6 %6 8 598 3 4 8 37
1 65 6 6 6 31 65 6 6 8 58 8
1 37 53 636 6 313 86 3 7 81 81 48 3 7 81 6 33 7 317 8 9 3 8 6 1 39963 681 313936 6
%695 1 534 317 85&'5 858 31&('561 17 316 3 7 3936 49 8)*'''5&+
,9 3 8 633936 4))-''5&+ ./01 2"3!4 5 67!189 : 8$96617853 636 %6 8 598 3 4 8 37
1 65 6 6 6 31
0120452404676289 59 2809012 2 060212502 446 224 28 8698461 289 20 9 29 60 97 82 2 1260 2 467628 9 2 4 012609 42!4010124 954 502 4 12514 20 269 46!401012502 4 28094001 971012 89 29 20!22 012
46"046 9 4828!401995!401209 29 !1414659 287 889! !40101212 9 !4 2 9269 18 7466025#22 84 9 012 4049 $0122 04 2995660255 69262!289 0126760 707 2!1410 269 !1226 7 4 9 012 4612502 4 954 9 012 89 29 46 46280 4 2 001280901260 2 88461 284 09012 9959 29 !141
426012502 47094062 8 89!64009 09 9 5609 42 12514 20 269 04 797609 8 969010012424674072 2
%& '() *'+ *,-
12 2452 467628094 7012502 4 95012609 42 9 9 ! 884601. 9004 !122!401 752 9 7 206 97 80124 75 2 2 246597 02800122 89 9 7 4 8 62!4 995 87064 0901242!40109 8 9 90 59 252 069 012995 966012 4212 502 44 2870127 206468461 289 099 29 7 4 9 012995 1299546597 0289 9004 5267 9 0289 0127 82
42!1410 269 !12269
46 7 4 9 0120 129959 29 8461 2012502 400122 0 29 012 514 2 95!12 24059 2689! 09012 97 89 29 !141 7 620!22 0120 2 46 /404269 7 20!122 2452 6 !482 950120231 0902$2220231 $995 2 01 9542509525
0 1234568955 53 5 695 5 2 5 6 695 65 345!2"#695 6#34 5$% 3 36 # & 5 2$5#" 3 5$ !5 5 66 395!6# #"5 ! 5 #' 39 "# 3 695 65 "# 695 5&(95 65 $#2 966## 5 !5#"695 5 !"
% # !5!# 6#6953# '5%# 2 # !5695 6#34 5& )55 ! # 695 %#26#"695 6#34% !*' #2 !5 #"695 3 553 5 5 5 #%5!&+ #5!5 695 65 #'5!!#, "#695 5$%2 45 !695 345!2$%695 3 5 $ !5 & -./0/ (9 3#$ 6 # 39 5!#5 695"2 36 # #"$#69 16 345 ! 1234568955 53 5& +6 $ 3
% 6#695$23456,955 53 5*$26, 69695$##3# '5%# 5'5 $ 5 # 5"# 6 34 #5 6 # * ! #9 6 5 66 395!6# 6"#"55! 6953 5#"695 6 345& (9 39 5 53# # 3 # 26 # "# 6#34% ! ,955 6 34 !53 #6522 5! 2 6 5#2 %&
12343564
789 9 5342645356425254433 5 42342 53 24 2542!"#2235$%235234434 $4 $5 4424 2 432$4 532343564" &25322343564454 35 4422 3453 5 422$34"124222'5352 4434 5 35622$3424234 '2%$6444344322454323442'4$645 "(322544442 22 $ 234 3 54)$4454232$3435 64453" * 1234356453$25
01234
67889 8 8
8 8 99 8 99 7889 7 787 7 !8 78 98 8 7
" #8
8#8 7
897 #89 99 878
$%2&'(4
) 78 998 9 7 * 78 8 78 8 87 98 8 78 ) 78 79 "8 9989 9 7 * 78 9 98+7 99 78 8
98 8,"9 78 8 7 "8 8 98 8 9989*
8"97 + 9 8 77 !8 8 78 "78 98 " 78 7
8 78 8 98 !88 8 8 8 + 9+ 78 98 98+7 78 7 - 9989 9 7 8 8 8 8 7 !8 8" 8
8
8 7 7 . 7 9 " + 878 7 78 /89 "80 7 9 7 - 9989 9 7 7 7 8
98 #8 78 7 "7 1 998 * 6898 2
+7
$312&425334
) 98* 9
8 8
" 7 78 #8 89 98 8 9 89 99 #8 87 8 7 7 987 8 98 8 8 +
9 78 78 87 7 77 78 "78 98 6 9
8 8 8 8 " 77 78 8 77 + 8 77
"8 78 78
8 7 ,"8 8 9 68 !8 8 9
8 7 9
" 8 !8 99.8 9
8 78 "999.8 9
8
9 #8 87 8 8
" 8 !8 9.8 9
8 #8 8 8 "78 98 98 8 !8 #8 78 #7+8 77 78
7 "7 8#87 78 887 7 7 78 7 + 878 87787 7 9 787 78 9 9" 7 ) 7 * 78 #8 8
" 78 #8 77 #7+8 78 8 .8 "78 8 7 98#8 78
8 7 78 8 8
$%2&'(3(25334
887 9 /89:80 8
8 /98"0 ; +7 9 7 8 9 7 987 9
8
; +7 8+< 9 /;9880 8
8 /98"0 ; +7 9 7 8 9 7
+7 9
8
67 8
8 8 89 8#8 9 7 9 89 99 8 8 98 " 8 ! 8 8 8 7 88 78 !8 7
8 8* 8 " 787 78 9 1 8 8 8 78 7 987 98 897 * "7 #8 78 8 +877 + "8 8 9 !8 8
78* 8 7 8* 8 " 8 7 9 7 8* 7 99 "8 "8 !8 7 78 8887 8
8 8*
78 7 " 98 99 78 8# 87 =7 78 7 8
8 9 #8 8 7 98 #8 78 8 / 8 8 7889 80
!8 9 87 78 7 78
8 8
+7 /9 >0 987 /9 60 78 9 87 78 8 8
+7 /9 60 987
/9 0 ! .
8 998 9
8 78 9 87 78 8 78 "78 7 78 78 87 7 78 9 78
"78 7 7889#8 ) 7 78 8 78 "78 7 78 "78 7 7889#8 #8 78 8 9 87 * 78
8 998 8+
?@ABCDEFBGHDCIFC?ABJ?KFCLMNB?@ABDCBO@PQMNB?@ARSBTU?LV7
8 8 99 8 98
8 77 7
77 #8 7 987 7 98 7 9
89 99 " 87 8 !8 87 78 "78 7 78 7 77 78 "8 9 + 7 98 ;8 7 7 88 7 98 8
8 9 77 + ;8 7 7 7 98 8 79 9 9 77 +
W9 7
8 + 7 "+8
X88 + 8 8 78 8 "8* 8
8 #8 7 "9 99 8 87
8," 887 !8 "8 8Y
0 2344546789 74 789 7 4 8 7 473 7 7 87 7 54 45464 84 4 584 0 5847789 789 957789 8 3 8 877 4 5 87 47 7 87 548 543 3 546
4 5 7 289 3 87 3 9 4 5847 8 4 !"#$%7 789 38 789 8 75 87 78 7 854
878 78 54 75789 & 4 74 '484 7 87344546789 7 789 848 84 37 37 8 78 7 (4 7 78 787 8 7
4546753 8 789 837 5 753 547 4 4546 7 7 &5 4 5 87 4 7 &5 78 787 0 )5 7 789 546 74 789 7 3 874 7583 54 8688 546 7 7 4 5 87 3 57 8 4546 7 & 4 4 8 7 87 87 79 6 8 688
289 75
7 7 457 63 584 87 789 75 874 87 789 & 45454654 584 48 *
54665 4 4 5 87 448 546 87 865 45
77 58+,8 4789 5
7 -6 4 75 4 584546
88789 75 43 5 45 7 63 584 3 5 55
0 )87 546 39 8789 5 7546877 6 487./055 2 1357 4 8 3 7 0 +8 44 87 5 546 4 5 87 8765 4 45465
77 58+, 75 55 4854789 4 5 87 3 7 4
+844 87 +. 0 28 9
87254537 54687 354,4854789 4 5 87 55 87 5 * 7 59 87 456789:;:<=>:?@A: 59 5 5469954 0 +5 754643 78&57 7
584 84
789 7 9 4 B545343 78&57 7 847 7 4 789 46 8C/ DE@FGH:IJ:KLMN:;:O:?@A:G6?P67Q:RSSG6R7TJ 0 U9
5789 5
7&5 *789 4374 8765 4 5
7+4 4 5 789 87 387 84857 84 789 5
7 83 4 7 83 7 4 89 57@SJ:H6R5JPJA:H:V:H@SPW
3 5848 789 75 55 9 4 84X
0 + 8 3 &57 789 0 289 4 5 87 0 +5
7+8 4,8773 0 59 4546 9 7&87 546 & 5 0 2 7 4546 9 7&87 546 & 7 0 Y854 3 3 546 4 5844 45469 7&87 546 & 8 0 2 5 3 3 546 4 5 87 , 0 289 4546 46 0
&57 789 7 7 3 3 54687 & 7 8778 584454 8 * 7 87 789 5 5 545 4
5 8465 454 9 58487
5848&57 7 847 7 4 789 46 878 5848 & 8 7537 8 &57 789 4 7 9 87 46 783 5 3 584837 '4 584 83 564 855 54 9 5848 &57 789 Z5 54654 584 879 46 7 74 987 5847 1357 854 5848 7
8 83 3 897 4 7789346546 8&4&7 [ 87 3 7 344 7546789 4
6 7289 & 454 85 5463 9 74 4 39 75 7 984 5 46 74 789 8 54 9 64
5
89 8
546544 7&57 7 \ \
\
Y54
1234567895 5 75684943 586
17895 5 9 6 5746 586
4
83 5 1 583 84 48 986 5389 5
756847895 1 5 75 4 9494437438
! 5 5385
7568 484949 8"5 436 #949 8 3 986868$
% %
& 4868 #8643
9 #" 5 886 9 5 4 9'43
#'43438 3 #" 5 9 52 8 4 " 5(8
9 59 538943 586" 7589 8 5 8) 2 8 946 78 4*& 8 )869 366 78 428 #5 5 + 8#9 , & 4868 #8643935833 #483 75 8 5(8
68 #869478 9 9 89889 49 834 8949 875 8"56538 8) 2 8
4 486 78 4& 8 5384534
83 5 "9 4# 9 8385385 4434
83 5 52 4 5
&46 9 9 5 528 48 986 #5-
38872 85 5352 883 9 5 38 48359 839 55 59
0
23456789 36
0
589 36
0
37543689 36
0
95 789 36
0
23645 889 36
1
23456789 9
1
46 9
1
976 9
1
39 6 9
1 937 9
1 234356789
2344 56789 2344 5678979 35
6
563 344 56789 397 3 78958
3 !"# 8 6 $ 356789 8% &3 53&&394$' 3 79 &8
8393& 567985743( 39&79$89 3 3&
85) *+,-./0*1279 73 85'4' 74&75689 $8954' 893539% $3 (8 479 '5 4 7(893&75689
89893
57 &33 5$54
79 585$54
67 539 8 37 8
3 63 5$489 8574 344 6 4 33 6 5$ 8 489 678 8% 95$7336 (6
45744 7 35 678 7 8&4 48754 79
858 98& 79 33( 79 &8
8396
012345674812 1 4 7 82
1 8
5 24 38 3 1 51 5 7 82 3 182 712345674812 5 5 746 41 4 3 1 823 4 52 482 82 4 63 51 5 7 82 8534 4 83 822 5 823 82 41 822 5 4 3 41 4 5 41 3 3 15 63 823 612 87 514 4 41 51 53 22 5 823 4 52 4 84 4 3 712 4 4 164 5 823 712383482 1 41 164 5 4 3 41 4 5 823 3382 4 516 4 63 823 1 4 822 5 823 63 82 33 51 5 7 82 83 38 8 5 82 1 5 4812 4 16 214 82 712345674812 8234 1 3 5 4 63 823 15 3 3 182 4 822 5 4 3 41 4 5 4 4 3 46 34 8241 84 5145682 51 4 1 87 3 5 3 4 3 6513 83 3 4 24 1 5 182 12 34 82 33 1 4 7 82 51 5 7 82 382 5 67 3 5874812 71 5 41 38 5 3823 5 36482 82 8 5
878 27 2 33 5 15882 1 5 45 23 833812 7 82 58 48 3 7 51 53 2 63 823 84 14 4 822 5 2 164 5 4 3 823 87 85 74 7124 74 4 3517 4 4 4 1 5 4 83 712 865 4812 884 45 5 8 5 1 14 4 3517 4 4 4 2 4 4 3 5 4 814 12 4 823 83 51 3 548 31 4 1 24 1 63 7 823 84 4 823 182 4 164 5 4 3 3382 4 516 63 823 15 3 3 7122 7482 4 822 5 4 3 83 8345864 4 5 1 5 5 4 5 5 1 5 4 4 4 1 4 3517 43 348 15 15 5 8 4 2 83 385 51 4 3882 5874812
8234 4 63 823 84812 1 51 53 365516282 4 63 82 3 3 1 4 7 82 2 518 5182 7124 74 84 4 4 4 1 4 3517 43 5 36482 82 7 24 5 3834 27 41 5 1 14 3517 43 2 7 82 3 5 83 2 5 1 5874812 3 12 3 4 7 82 83 36
878 24 6587 4 0124826163 7 2 6587 4812 1 51 5 7 823 83 1 58 5 8 154 27 15
878 24 1 5 4812 3 3 7155 74 4 2381282
SCREW CONVEYORS A screw conveyor or auger conveyor is a mechanism that uses a rotating helical screw blade, called a "flighting", usually within a tube, to move liquid or granular materials. They are used in many bulk handling industries. Screw conveyors in modern industry are often used horizontally or at a slight incline as an efficient way to move semisolid materials, including food waste, wood chips, aggregates, cereal grains, animal feed, boiler ash, meat and bone meal, municipal solid waste, and many others. The first type of screw conveyor was the Archimedes' screw, used since ancient times to pump irrigation water. They usually consist of a trough or tube containing either a spiral blade coiled around a shaft, driven at one end and held at the other, or a "shaftless spiral", driven at one end and free at the other. The rate of volume transfer is proportional to the rotation rate of the shaft. In industrial control applications the device is often used as a variable rate feeder by varying the rotation rate of the shaft to deliver a measured rate or quantity of material into a process. Screw conveyors can be operated with the flow of material inclined upward. When space allows, this is a very economical method of elevating and conveying. As the angle of inclination increases, the capacity of a given unit rapidly decreases. The rotating part of the conveyor is sometimes called simply an auger In agriculture
This combine harvester uses a screw conveyor within the tube to discharge grain into the trailer alongside The "grain auger" is used in agriculture to move grain from trucks and grain carts into grain storage bins (from where it is later removed by gravity chutes at the bottom). A grain auger may be powered by an electric motor; a tractor, through the power take-off; or sometimes an internal combustion engine mounted on the auger. The helical flighting rotates inside a long metal tube, moving the grain upwards. On the lower end, a hopper receives grain from the truck or grain cart. A chute on the upper end guides the grain into the destination location.
First Grain Auger invented in 1945 in Toronto, Canada The modern grain auger of today's farming communities was invented byPeter Pakosh. His grain mover employed a screw-type auger with a minimum of moving parts, a totally new application for this specific use. At Massey Harris(later Massey Ferguson), young Pakosh approached the design department in the 1940s with his auger idea, but was scolded and told that his idea was unimaginable and that once the auger aged and bent that the metal on metal would, according to a head Massey designer, "start fires all across Canada" Pakosh, however, went on to design and build a first prototype auger in 1945, and 8 years later start selling tens of thousands under the 'Versatile' name, making it the standard for modern grain augers. A specialized form of grain auger is used to transfer grain into a seed drill, and is usually quite a lot smaller in both length and diameter than the augers used to transfer grain to or from a truck, grain cart or bin. This type of auger is known as a "drill fill". Grain augers with a small diameter, regardless of the use they are put to, are often called "pencil augers". Other uses Various other applications of the screw or auger conveyor include its use in snowblowers, to move snow towards an impeller, where it is thrown into the discharge chute. Combine harvesters use both enclosed and open augers to move the unthreshed crop into the threshing mechanism and to move the grain into and out of the machine's hopper. Ice resurfacers use augers to remove loose ice particles from the surface of the ice. An auger is also a central component of an injection molding machine. An auger is used in some rubbish compactors to push the rubbish into a lowered plate at one end for compaction. Augers are also used to force food products through dies to produce pellets. These are then processed further to produce products such as bran flakes. Augers are also used in oil fields as a method of transporting rock cuttings away from the shakers to skips. Augers are also used in some types of pellet fed barbecue grills, to move fuel from a hopper into the firebox in a controlled manner. Augers are often used in machining, wherein the machine tools may include an auger to direct the swarf (scrap metal or plastic) away from the work piece. Screw conveyors can also be found in Waste Water Treatment Plants to evacuate solid waste from the treatment process.
Hydraulic Conveyor 1
A conveyor for handling solid material in which the material is flushed from a slag area, ground up, and then pumped to a discharge area.
Machines of all types need power. Power allows the machines to do specific kinds of work. Two of the most efficient and compact forms of power for machines are hydraulic and pneumatic systems. Hydraulics and pneumatics can be configured into different types of power sources to lift, lower, pull, push, turn, rotate and move machines carrying tremendous loads. Tools can also be powered to break stone, join steel and cut wood. Hydraulics and pneumatics provide the energy to make work happen. Hydraulics work on the principle of pressurized fluid forcing mechanical action. A hydraulic system installed on a machine is called a hydraulic circuit. Hydraulic circuits are composed of a pump to compress the fluid, lines to carry the fluid, a cylinder where the fluid is pumped and a piston moved by the pressurized fluid in the cylinder. Hydraulics can also actuate shafts to power hydraulic motors and conveyors.
2
The heavy-duty, extra-capacity Model 2000 hydraulic conveyor saves time, labor, material and money for big jobs such as road widening, installing pipe bedding, trench filling and shouldering. The unit mounts to road graders, loaders and tractors for efficient delivery of both free-flowing and large, chunky materials without hand l
3
ELEVATOR An elevator (lift in British English) is a type of vertical transport equipment that efficiently moves people or goods between floors (levels, decks) of a building, vessel or other structure. Elevators are generally powered by electric motors that either drive traction cables or counterweight systems like a hoist, or pump hydraulic fluid to raise a cylindrical piston like a jack. In agriculture and manufacturing, an elevator is any type of conveyor device used to lift materials in a continuous stream into bins or silos. Several types exist, such as the chain and bucket bucket elevator, grain auger screw conveyor using the principle of Archimedes' screw, or the chain and paddles/forks of hay elevators.
Design Some people argue that elevators began as simple rope or chain hoists (see Traction elevators below). An elevator is essentially a platform that is either pulled or pushed up by a mechanical means. A modern day elevator consists of a cab (also called a "cage" or "car") mounted on a platform within an enclosed space called a shaft or sometimes a "hoistway". In the past, elevator drive mechanisms were powered by steam and water hydraulic pistons or by hand. In a "traction" elevator, cars are pulled up by means of rolling steel ropes over a deeply grooved pulley, commonly called a sheave in the industry. The weight of the car is balanced by a counterweight. Sometimes two elevators are built so that their cars always move synchronously in opposite directions, and are each other's counterweight. The friction between the ropes and the pulley furnishes the traction which gives this type of elevator its name. Hydraulic elevators use the principles of hydraulics (in the sense of hydraulic power) to pressurize an above ground or in-ground piston to raise and lower the car (see Hydraulic elevators below). Roped hydraulics use a combination of both ropes and hydraulic power to raise and lower cars. Recent innovations include permanent 1
magnet motors, machine room-less rail mounted gearless machines, and microprocessor controls. The technology used in new installations depends on a variety of factors. Hydraulic elevators are cheaper, but installing cylinders greater than a certain length becomes impractical for very-high lift hoistways. For buildings of much over seven storys, traction elevators must be employed instead. Hydraulic elevators are usually slower than traction elevators. Elevators are a candidate for mass customization. There are economies to be made from mass production of the components, but each building comes with its own requirements like different number of floors, dimensions of the well and usage patterns.
Elevator doors Elevator doors protect riders from falling into the shaft. The most common configuration is to have two panels that meet in the middle, and slide open laterally. In a cascading telescopic configuration (potentially allowing wider entryways within limited space), the doors run on independent tracks so that while open, they are tucked behind one another, and while closed, they form cascading layers on one side. This can be configured so that two sets of such cascading doors operate like the center opening doors described above, allowing for a very wide elevator cab. In less expensive installations the elevator can also use one large "slab" door: a single panel door the width of the doorway that opens to the left or right laterally. Some buildings have elevators with the single door on the shaft way, and double cascading doors on the cab. Machine room-less (MRL) elevators
2
Machine room-less elevators are designed so that most of the components fit within the shaft containing the elevator car; and a small cabinet houses the elevator controller. Other than the machinery being in the hoistway, the equipment is similar to a normal traction elevator. The benefits are: •
creates more usable space
•
use less energy (70-80% less than hydraulic elevators)
•
uses no oil
•
all components are above ground similar to roped hydraulic type elevators (this takes away the environmental concern that was created by the hydraulic cylinder on direct hydraulic type elevators being stored underground)
•
slightly lower cost than other elevators
•
can operate at faster speeds than hydraulics but not normal traction units.
Types of hoist mechanisms There are at least four means of moving an elevator:
Traction elevators •
Geared and gearless traction elevators
3
Geared traction machines are driven by AC or DC electric motors. Geared machines use worm gears to control mechanical movement of elevator cars by "rolling" steel hoist ropes over a drive sheave which is attached to a gearbox driven by a highspeed motor. These machines are generally the best option for basement or overhead traction use for speeds up to 500 feet per minute (3 m/s). In order to allow accurate speed control of the motor, to allow accurate levelling and for passenger comfort, a DC hoist motor powered by an AC/DC motor-generator (MG) set was the preferred solution in high-traffic elevator installations for many decades. The MG set also typically powered the relay controller of the elevator, which has the added advantage of electrically isolating the elevators from the rest of a building's electrical system, thus eliminating the transient power spikes in the building's electrical supply caused by the motors starting and stopping (causing lighting to dim every time the elevators are used for example), as well as interference to other electrical equipment caused by the arcing of the relay contactors in the control system. Contemporary cheaper installations, such as those in residential buildings and lowtraffic commercial applications generally used a single or two-speed AC hoist machine. The widespread availability of cheap solid state AC drives has allowed infinitely variable speed AC motors to be used universally, bringing with it the advantages of the older motor-generator based systems, without the penalties in terms of efficiency and complexity. The older MG-based installations are gradually being replaced in older buildings due to their poor energy efficiency. Gearless traction machines are low-speed (low-RPM), high-torque electric motors powered either by AC or DC. In this case, the drive sheave is directly attached to the end of the motor. Gearless traction elevators can reach speeds of up to 2,000 feet per minute (10 m/s), or even higher. A brake is mounted between the motor and drive sheave (or gearbox) to hold the elevator stationary at a floor. This brake is usually an external drum type and is actuated by spring force and held open electrically; a power failure will cause the brake to engage and prevent the elevator from falling (see inherent safety and safety engineering). In each case, cables are attached to a hitch plate on top of the cab or may be "underslung" below a cab, and then looped over the drive sheave to a counterweight attached to the opposite end of the cables which reduces the amount of power needed to move the cab. The counterweight is located in the hoistway and rides a separate railway system; as the car goes up, the counterweight goes down, and vice versa. This action is powered by the traction machine which is directed by the controller, typically a relay logic or computerized device that directs starting, acceleration, deceleration and stopping of the elevator cab. The weight of the counterweight is typically equal to the weight of the elevator cab plus 40-50% of the capacity of the elevator. The grooves in the drive sheave are specially designed to prevent the cables from slipping. "Traction" is provided to the ropes by the grip of the grooves in the sheave, thereby the name. As the ropes age and the traction grooves wear, some traction is lost and the ropes must be replaced and the sheave repaired or replaced. Sheave and rope wear may be significantly reduced by ensuring that all ropes have equal tension, thus sharing the load evenly. Rope tension equalization may be achieved using a rope tension gauge, and is a simple way to extend the lifetime of the sheaves and ropes. Elevators with more than 100 feet (30 m) of travel have a system called compensation. This is a separate set of cables or a chain attached to the bottom of 4
the counterweight and the bottom of the elevator cab. This makes it easier to control the elevator, as it compensates for the differing weight of cable between the hoist and the cab. If the elevator cab is at the top of the hoist-way, there is a short length of hoist cable above the car and a long length of compensating cable below the car and vice versa for the counterweight. If the compensation system uses cables, there will be an additional sheave in the pit below the elevator, to guide the cables. If the compensation system uses chains, the chain is guided by a bar mounted between the counterweight railway lines.
Hydraulic elevators •
Conventional hydraulic elevators. They use an underground cylinder, are quite common for low level buildings with 2–5 floors (sometimes but seldom up to 6–8 floors), and have speeds of up to 200 feet per minute (1 m/s).
•
Holeless hydraulic elevators were developed in the 1970s, and use a pair of above ground cylinders, which makes it practical for environmentally or cost sensitive buildings with 2, 3, or 4 floors.
•
Roped hydraulic elevators use both above ground cylinders and a rope system, allowing the elevator to travel further than the piston has to move.
The low mechanical complexity of hydraulic elevators in comparison to traction elevators makes them ideal for low rise, low traffic installations. They are less energy efficient as the pump works against gravity to push the car and its passengers upwards; this energy is lost when the car descends on its own weight. The high current draw of the pump when starting up also places higher demands on a building’s electrical system. There are also environmental concerns should either the lifting cylinder leak fluid into the ground. The modern generation of low cost, machine room-less traction elevators made possible by advances in miniaturization of the traction motor and control systems challenges the supremacy of the hydraulic elevator in their traditional market niche.
Climbing elevator A climbing elevator is a self-ascending elevator with its own propulsion. The propulsion can be done by an electric or a combustion engine. Climbing elevators are used in guyed masts or towers, in order to make easy access to parts of these constructions, such as flight safety lamps for maintenance. An example would be the Moonlight towers in Austin, Texas, where the elevator holds only one person and equipment for maintenance. The Glasgow Tower — an observation tower in Glasgow, Scotland — also makes use of two climbing elevators.
Uses of elevators Passenger service A passenger elevator is designed to move people between a building's floors. Passenger elevators capacity is related to the available floor space. Generally passenger elevators are available in capacities from 1,000 to 6,000 pounds (500– 5
2,700 kg) in 500-pound (230 kg) increments.[citation needed] Generally passenger elevators in buildings of eight floors or fewer are hydraulic or electric, which can reach speeds up to 200 feet per minute (1 m/s) hydraulic and up to 500 feet per minute (152 m/min) electric. In buildings up to ten floors, electric and gearless elevators are likely to have speeds up to 500 feet per minute (3 m/s), and above ten floors speeds range 500 to 2,000 feet per minute (3–10 m/s).[citation needed] Sometimes passenger elevators are used as a city transport along with funiculars. For example, there is a 3-station underground public elevator in Yalta, Ukraine, which takes passengers from the top of a hill above the Black Sea on which hotels are perched, to a tunnel located on the beach below. At Casco Viejo station in the Bilbao Metro, the elevator that provides access to the station from a hilltop neighborhood doubles as city transportation: the station's ticket barriers are set up in such a way that passengers can pay to reach the elevator from the entrance in the lower city, or vice versa. See also the Elevators for urban transport section.
Types of passenger elevators
The former World Trade Center's twin towers used skylobbies, located on the 44th and 78th floors of each tower Passenger elevators may be specialized for the service they perform, including: hospital emergency (Code blue), front and rear entrances, a television in high-rise buildings, double decker, and other uses. Cars may be ornate in their interior appearance, may have audio visual advertising, and may be provided with specialized recorded voice announcements. Elevators may also haveloudspeakers in them to play calm, easy listening music. Such music is often referred to as elevator music. An express elevator does not serve all floors. For example, it moves between the ground floor and a skylobby, or it moves from the ground floor or a skylobby to a range of floors, skipping floors in between. These are especially popular in eastern Asia.
Capacity Residential elevators may be small enough to only accommodate one person while some are large enough for more than a dozen. Wheelchair, or platform elevators, a specialized type of elevator designed to move a wheelchair 12 feet (3.7 m) or less, can often accommodate just one person in a wheelchair at a time with a load of 750 pounds (340 kg).[30][31]
Freight elevators 6
A specialized elevator from 1905 for lifting narrow gauge railroad cars between a railroad freight house and the Chicago Tunnel Company tracks below
The interior of a freight elevator. It is very basic yet rugged for freight loading. A freight elevator, or goods lift, is an elevator designed to carry goods, rather than passengers. Freight elevators are generally required to display a written notice in the car that the use by passengers is prohibited (though not necessarily illegal), though certain freight elevators allow dual use through the use of an inconspicuous riser. In order for an elevator to be legal to carry passengers in some jurisdictions it must have a solid inner door. Freight elevators are typically larger and capable of carrying heavier loads than a passenger elevator, generally from 2,300 to 4,500 kg. Freight elevators may have manually operated doors, and often have rugged interior finishes 7
to prevent damage while loading and unloading. Although hydraulic freight elevators exist, electric elevators are more energy efficient for the work of freight lifting.[citation needed]
Sidewalk elevators A sidewalk elevator is a special type of freight elevator. Sidewalk elevators are used to move materials between a basement and a ground-level area, often the sidewalk just outside the building. They are controlled via an exterior switch and emerge from a metal trap door at ground level. Sidewalk elevator cars feature a uniquely shaped top that allows this door to open and close automatically.[32]
Stage elevators Stage and orchestra elevator are specialized elevators, typically powered by hydraulics, that are used to lift entire sections of a theater stage. For example, Radio City Music Hall has four such elevators: an "orchestra elevator" that covers a large area of the stage, and three smaller elevators near the rear of the stage. In this case, the orchestra elevator is powerful enough to raise an entire orchestra, or an entire cast of performers (including live elephants) up to stage level from below. •
The pit beneath the orchestra lift at Radio City Music Hall
•
Orchestra lift at Radio City Music Hall as viewed from beneath the stage
8
Band brake This article does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (December 2009)
A band brake is a primary or secondary brake, consisting of a band of friction material that tightens concentrically around a cylindrical piece of equipment to either prevent it from rotating (a static or "holding" brake), or to slow it (a dynamic brake). This application is common on winch drums and chain saws and is also used for some bicycle brakes. A former application was the locking of gear rings in epicyclic gearing. In modern automatic transmissions this task has been taken over entirely by multiple-plate clutches or multipleplate brakes.[citation needed]
Features Band brakes can be simple, compact, rugged, and can generate high force with a light input force. However, band brakes are prone to grabbing or chatter and loss of brake force when hot. These problems are inherent with the design and thus limit where band brakes are a good solution.
Effectiveness One way to describe the effectiveness of the brake is as , where is the coefficient of friction between band and drum, and is the angle of wrap. With a large , the brake is very effective and requires low input force to achieve high brake force, but is also very sensitive to changes in . For example light rust on the drum may cause the brake to "grab" or chatter, water may cause the brake to slip, and rising temperatures in braking may cause the coefficient of friction to drop slightly but in turn cause brake force to drop greatly. Using a band material with low increases the input force required to achieve a given brake force, but some low- materials also have more consistent across the range of working temperatures.
SINGLE BLOCK OR SHOE BRAKE 1
Cycle Shoe Brake
A single block or shoe brake is shown below. It consists of a block or shoe which is pressed against the rim of a revolving brake wheel drum. The block is made of a softer material than the rim of the wheel. This type of a brake is commonly used on railway trains and tram cars. The friction between the block and the wheel causes a tangential braking force to act on the wheel, which retard the rotation of the wheel. The block is pressed against the wheel by a force applied to one end of a lever to which the block is rigidly fixed. The other end of the lever is pivoted on a fixed fulcrum O.
2
Single block brake. Line of action of tangential force passes through the fulcrum of the lever.
Let P = Force applied at the end of the lever, RN = Normal force pressing the brake block on the wheel, r = Radius of the wheel, 2θ = Angle of contact surface of the block, µ = Coefficient of friction, and Ft = Tangential braking force or the frictional force acting at the contact surface of the block and the wheel. If the angle of contact is less than 60°, then it may be assumed that the normal pressure between the block and the wheel is uniform. In such cases, tangential braking force on the wheel,
Ft= µ.RN and the braking torque,TB = Ft.r = µ RN. r Let us now consider the following three cases : CASE I : When the line of action of tangential braking force (F) passes through the fulcrum O of the lever, and the brake wheel rotates clockwise as shown in Fig. 25.1 (a), then for equilibrium, taking moments about the fulcrum O, we have, 3
∴
Braking torque,
It may be noted that when the brake wheel rotates anticlockwise, then the braking torque is same, i.e.
Case 2 : When the line of action of the tangential braking force (F) passes through a distance ‘a’ below the fulcrum O, and the brake wheel rotates clockwise, then for equilibrium, taking moments about the fulcrum O,
Single block bracke. Line of action passes below the fulcrum.
Hence,
and braking torque,
When the brake wheel rotates anticlockwise, then for equilibrium,
4
and braking torque,
Case 3 : When the line of action of the tangential braking force passes through a distance ‘a’ above the fulcrum, and the brake wheel rotates clockwise then for equilibrium,taking moments about the fulcrum O, we have
Single block brake. Line of action passes above the fulcrum.
Hence,
and braking torque,
When the brake wheel rotates anticlockwise, then for equilibrium, taking moments about the fulcrum O, we have
and braking torque,
BAND AND BLOCK BRAKE 5
The band brake may be lined with blocks of wood or other material. The friction between the blocks and the drum provides braking action. Let there are ‘n’ number of blocks, each subtending an angle 2 θ at the centre and the drum rotates in anticlockwise direction.
Band and block brake.
6
Consider one of the blocks (say first block). This is in equilibrium under the action of the following forces : 1. Tension in the tight side (T1), 2. Tension in the slack side (T1') or tension in the band between the first and second block, 3. Normal reaction of the drum on the block (RN), and 4. The force of friction (µ.RN). Resolving the forces radially, we have Resolving the forces tangentially, we have Dividing above equations
Similarly it can be proved for each of the blocks that
Braking torque on the drum of effective radius re,
7
EOT CRANE The most adaptable and the most widely used type of power driven crane for indoor service is undoubtedly the three motion EOT crane. It serves a larger area of floor space within its own travelling restrictions than any other permanent type hoisting arrangement. As the name implies, this type of crane is provided with movement above the floor level. Hence it occupies no floor space and this can never interface with any movement of the work being carried out at the floor of the building. The three motions of such crane are the hoisting motion and the cross travel motion. Each of the motions is provided by electric motors. The above characteristics have made this type of crane suitable for medium and heavy workshop and warehouses. No engineering erection shop, machine shop, foundry, heavy stores is complete without an EOT crane. In a steel plant, rolling mill, thermal power plant, hydraulic power plant, nuclear power plant, this type of crane is considered indispensable. In short in all industries, wherein heavy loads are to be handled, EOT crane find its application. 1
EOT Crane Parts: A EOT crane consists of two distinct parts •
1. Bridge
•
2. Crab Bridge:
The Bridge consists of two main girders fixed at their ends and connected to another structural components called the end carriages. In the two end carriages are mounted the main runners or wheels (four or more) which provide the longitudinal motion to the main bridge along the length of the workshop. The motion of the bridge is derived from an electric motor which is geared to a shaft running across the full span of the bridge and further geared to a wheel at each end. In some design separate motors may be fitted at each corner of the main bridge. The wheels run on two heavy rails 2
fixed above the floor level along the length of the shop on two girders, called gantry girder. Crab: The Crab consists of the hoisting machinery mounted on a frame, which is in turn mounted on at least four wheels and fitted with suitable machinery for traversing the crab to and fro across the main girders of the crane bridge. Needless to mention that the crab wheels run on two rail sections fixed on the top flange of the main bridge. Thus the load hook has three separate motions, these being the hoisting, cross traverse of the crab, and longitudinal travel of the whole crane. Each motion is controlled independently of the other motions by separate controllers situated in a control cage or in a suitable position for controlling from the floor by pendent chains. The essential parts are:
3
1. Bridge– 2 No’s 2. End carriage– 2 No’s 3. Wheel of the bridge– At least 4 No’s 4. Crab (without auxiliary hoist)– 1 No’s 5. Hoisting machinery set– 1 No’s 6. Wheels of crab– At least 4 No’s 7. Bottom Block (without auxiliary hoist)– 1 No’s 8. Lifting hook– 1 No’s 9. Rail on the gantry girder for crane movement– 2 No’s 10.
Rail on the bridge for crab movement– 2 No’s
11.
Operators cabin– 1 No’s
4
Introduction Material-handling equipment is equipment that relate to the movement, storage, control and protection of materials, goods and products throughout the process of manufacturing, distribution, consumption and disposal. Material handling equipment is the mechanical equipment involved in the complete system.[1] Material handling equipment is generally separated into four main categories: storage and handling equipment, engineered systems, industrial trucks, and bulk material handling.
Hoisting Mechanism. A hoist is a device used for lifting or lowering a load by means of a drum or lift-wheel around which rope or chain wraps. It may be manually operated, electrically or pneumatically driven and may use chain, fiber or wire rope as its lifting medium. The load is attached to the hoist by means of a lifting hook. • Hand-Chain Hoists. Hand chain hoists are portable lifting devices suspended from a hook and operated by pulling on a hand chain. There are two types currently in common use, the high-speed, high-efficiency hand hoist and the economy hand hoist. The economy hand hoist is similar in appearance to the highefficiency hand hoist except the handwheel diameter is smaller. This smaller diameter accounts for a smaller headroom dimension for the economy hoist. High-speed hoists have mechanical efficiency as high as 80 percent, employ Weston self-energizing brakes for load control, and can incorporate load-limiting devices which prevent the lifting of excessive overloads. They require less hand chain pull and less chain overhaul for movement of a given load at the expense of the larger head size when compared to economy hoists. As noted, this larger head size also creates a minimum headroom dimension somewhat greater than that for the economy hoists. High-speed hoists find application in production operations where low operating effort and long life are important. Economy hoists find application in
0|Page
construction and shop use where more compact size and lower unit cost compensate for the higher operating effort and lower efficiency. Both hoist types function in a similar manner. The hand chain operates over a handwheel which is connected via the brake mechanism and gear train to a pocket wheel over which the load chain travels. The brake is disengaged during hoisting by a one-way ratchet mechanism. In lowering, the hand chain is pulled continuously in a reverse direction to overcome brake torque, thus allowing the load to descend. Although a majority of hand chain hoist applications are fixed hook-suspended applications, sometimes a hand hoist is mounted to a trolley to permit horizontal movement of the load, as in a forklift battery-changing operation. This is accomplished by directly attaching the hoist hook to the trolley load bar, or by using an integrated trolley hoist which combines a high-speed hoist with a trolley to save headroom. Hand chain hoists are available in capacities to 50 tons (45 tonnes) • Pullers or Come-Alongs Pullers, or come-alongs, are lever-operated chain or wire rope hoists . Because they are smaller in size and lower in weight than equivalent capacity capacity hand chain hoists, they find use in applications where the travel (takeup) distance is short and the lever is within easy reach of the operator. They may be used for lifting or pulling at any angle as long as the load is applied in a straight line between hooks. There are two types of lever-operated chain or wire rope hoists currently in use: long handle and short handle. The long-handle variety, because of direct drive or numerically lower gear ratios, allows a greater load chain take-up per handle stroke than the short-handle version. Conversely, the shorthandle variety requires less handle force at the expense of chain take-up distance because of numerically higher gear ratios. Both types find use in construction, electrical utilities and industrial maintenance for wire tensioning, machinery skidding, and lifting applications. A reversible ratchet mechanism in the lever permits operation for both tensioning and relaxing. The load is held in place by a Weston-type brake or a releasable ratchet. Lever tools incorporating load-limiting devices via slip clutch, spring deflection, or handle-collapsing means are also available.
1
• Electric Hoists Electric hoists are used for repetitive or high-speed lifting. Two types are available: chain (both link and roller), in capacities to 15 tons (13.6tonnes); wire rope (see Fig. 10.2.22), inratings to 25 tons (22.7 tonnes). The typical hoist has a drum or sprocket centered in the frame, with the motor and gearing at opposite ends, the motor shaft passing through or alongside the drum or sprocket. Many have an integral load-limiting device to prevent the lifting of gross overloads. Electric hoists are equipped with at least two independent braking means. An electrically released brake causes spring-loaded disk brake plates to engage when current is off. When the hoist motor is activated, a solenoid overcomes the springs to release the brake. In the lowering direction, the motor acts as a generator, putting current back into the line and controlling the lowering speed. Some electric hoists use the same type of Weston brake as is used in hand hoists, but with this type, the motor must drive the load downward so as to try to release the brake. This type of brake generates considerable heat that must be dissipated —usually through an oil bath. The heat generated may also lower the useful-duty cycle of the hoist. If the Weston brake is used, an additional auxiliary hand-released or electrically released friction brake must be provided since the Weston brake will not act in the raising direction. All electric hoists have upper-limit devices; lower-limit devices are standard on chain hoists, optional on wire-rope hoists. Control is usually by push button: pendant ropes from the controller are obsolescent. Control is ‘‘deadman’’ type, the hoist stopping instantly upon release. Modern multiple-speed and variable-speed ac controls have made dc hoists obsolete. Single-phase ac hoists are available to 1 hp, polyphase in all sizes. The hoist may be suspended by an integral hook or bolt-type lug or may be attached to a trolley rolling on an I beam or monorail. The trolley may be plain (push type), geared (operated by a hand chain), or 2
motor-driven; the latter types are essential for heavier loads.
• Air Hoists Air hoists are similar to electric hoists except that air motors are used. Hoists with roller chain are available to 1 ton capacity, with link chain to 3 short tons (2.7 tonnes) and with wire rope to 15 short tons (13.6 tonnes) capacity. The motor may be of the rotary-vane or piston type. The piston motor is more costly but provides the best starting and lowspeed performance and is preferred for larger-capacity hoists. A brake, interlocked with the controls, automatically holds the load in neutral; control movement releases the brake, either mechanically or by air hoist may be suspended by a hook, lug, or trolley; the latter may be plain, geared, or air-motor-driven. Horizontal movement is limited to about 25 ft (7.6 m) because of the air hose, although a runway system is available with a series of normally closed ports that are opened by a special trolley to supply air to the hoist. Air hoists provide infinitely variable speed, according to the movement of the control valve. Very high speeds are possible with light loads. When severely overloaded, the air motor stalls without damage. Air hoists are smaller and lighter than electric hoists of equal capacity and can be operated in explosive atmospheres. They are more expensive than electric hoists, require mufflers for reasonably quiet operation, and normally are fitted with automatic lubricators in the air supply.
3
• Jacks Jacks are portable, hand-operated devices for moving heavy loads through short distances. There are three types in common use: screw jacks, rack-and-lever jacks, and hydraulic jacks. Bell-bottom screw jacks (Fig. 10.2.23) are available in capacities to 24 tons and lifting ranges to 14 in. The screw is rotated by a bar inserted in holes in the screw head or by a ratchet lever fitted to the head. Geared bridge jacks will lift up to 50 short tons (45 tonnes). A lever ratchet mechanism turns a bevel pinion; an internal thread in the gear raises the nonrotating screw. • Rack and lever jacks Consist of a cast-steel or malleable-iron housing in which the lever pivots. The rack toothed bar passes through the hollow housing; the load may be lifted either on the top or on a toe extending from the bottom of the bar. The lever pawl may be biased either to raise or to lower the bar, the housing pawl holding the load on the return lever stroke. Rack-and-lever jacks to 20 short tons (18 tonnes) are direct-acting. Lever-operated geared jacks range up to 35 short tons (32 tonnes). Lifting heights to 18 in (0.46 m) are provided.
4
• Track jacks These are rack-and-lever jacks which may be tripped to release the load. They are used for railroad-track work but not for industrial service where the tripping features might be hazardous. • Hydraulic jacks This consist of a cylinder, a piston, and a lever-operated pump. Capacities to 100 short tons (91 tonnes) and lifting heights to 22 in (0.56 m) are available. Jacks 25 short tons (22.7 tonnes) and larger may be provided with two pumps, the second pump being a high-speed unit for rapid travel at partial load
5
** A differential pulley chain hoist
6
Travelling Mechanism
The proper packaging of material to assist in handling can significantly minimize the handling cost and can also have a marked influence on the type of handling equipment employed. For example, partial carload lots of liquid or granular material may be shipped in rigid or nonrigid containers equipped with proper lugs to facilitate in-transit handling. Heavy-duty rubberized containers that are inert to most cargo are available for repeated use in shipping partial carloads. The nonrigid container reduces return shipping costs, since it can be collapsed to reduce space. Disposable light-weight corrugated-cardboard shipping containers for small and medium-sized packages both protect the cargo and permit stacking to economize on space requirements. The type of container to be used should be planned or considered when the handling mechanism is selected. SURFACE HANDLING Lift Trucks and Palletized Loads The basis of all efficient handling, storage, and movement of unitized goods is the cube concept. Building a cube enables a large quantity of unit goods to be handled and stored at one time. This provides greater efficiency by increasing the volume of goods movement for a given amount of work. Examples of cube-facilitating devices include pallets, skids, slip sheets, bins, drums, and crates. The most widely applied cube device is the pallet. A pallet is a low platform, usually constructed of wood, incorporating openings for the forks of a lift truck to enter. Such openings are designed to enable a lift truck to pick up and transport the pallet containing the cubed goods. Lift truck is a loose term for a family of pallet handling/transporting machines. Such machines range from manually propelled low-lift devices (Fig. 10.4.1) to internal combustion and electric powered ride-on high-lift devices . While some machines are substitutes in terms of function, each serves its own niche when viewed in terms of individual budgets and applications. Pallet trucks are low-lift machines designed to raise loaded pallets sufficiently off the ground to enable the truck to transport the pallet horizontally. Pallet trucks are available as manually operated and propelled models that incorporate a hydraulic pump and handle assembly. This pump and handle assembly enables the operator to raise the truck forks, and push/pull the load. ABOVE-SURFACE HANDLING Monorails 7
Materials can be carried on light, rigid trackage, as described for overhead conveyors (see below). Trolleys are supported by structural I beams, H beams, or I-beam-like rails with special flat flanges to improve rolling characteristics of the wheels. Size of wheels and smoothness of tread are important in reducing rolling resistance. Figure 10.4.11 shows a typical rigid trolley for traversing short-radius track curves. Typical dimensions for both types are given in Table 10.4.1. These trolleys may be plain, with geared handwheel and hand chain, or motordrive. For very low headroom, the trolley can be built into the hoist; this is known as a trolley hoist. Overhead Traveling Cranes An overhead traveling crane is a vehicle for lifting, transporting, and lowering loads. It consists of a bridge supporting a hoisting unit and is equipped with wheels for operating on an elevated runway or track. The hoisting unit may be fixed relative to the bridge but is usually supported on wheels, permitting it to traverse the length of the bridge. The motions of the crane—hoisting, trolley traversing, and bridging — may be powered by hand, electricity, air, hydraulics, or a combination of these. Hand-powered cranes are generally built in capacities under 50 tons (45 tonnes) and are used for infrequent service where slow speeds are acceptable. Pneumatic cranes are used where electricity would be hazardous or where advantage can be taken of existing air supply. Electric cranes are the most common overhead type and can be built to capacities of 500 tons (454 tonnes) or more and to spans of 150 ft (46 m) and over. Single-Girder Cranes (Fig. 10.4.12) In its simplest form, this consists of an I beam a supported by four wheels b. The trolley c traveling on the lower flanges carries the chain hoist, forming the lifting unit. The crane is moved by hand chain d turning sprocket wheel e, which is keyed to shaft f. The pinions on shaft f mesh with gears g, keyed to the axles of two wheels. An underslung construction may also be used, with pairs of wheels at each corner which ride on the lower flange of I-beam rails. Single-girder cranes may be hand-powered by pendant hand chains or electric-powered as controlled by a pendant push-button station. Electric Traveling Crane, Double-Girder Type (Fig. 10.4.13) This consists of two bridge girders a, on the top of which are rails on which travels the self-contained hoisting unit b, called the trolley. The girders are supported at the ends by trucks with two or four wheels, according to the size of the crane. The crane is moved along the track by motor c, through shaft d and gearing to the truck wheels. Suspended from the girders on one side is the operator’s cab e, containing the controller, or master switches, master hydraulic brake cylinder, warning device, etc. The bridge girders for small cranes are of the I-beam type, but on the 8
longer spans, box girders are used to give torsional and lateral stiffness. The girders are rigidly attached to the truck end framing, which carries the double-flanged wheels for supporting the bridge. The end frames project over the rails so that in case of a broken wheel or axle, the frame will rest on the rail, preventing the crane from dropping. One wheel axle on each truck is fitted with gears for driving the crane or is coupled directly to the shaft which transmits power from the gear reducer. On a cab-operated bridge, a brake, usually hydraulic, is applied to the motor shaft to stop the crane. Floor-operated cranes generally utilize spring engaged, electrically released brakes. The trolley consists of a frame which carries the hoisting machinery and is supported on wheels for movement along the bridge rails. The wheels are coupled to the trolley traverse motor through suitable gear reduction. Trolleys are frequently equipped with a second set of hoisting machinery to provide dual lifting means or an auxiliary of smaller capacity. The hoisting machinery consists of motor, motor brake, load brake, gear reduction, and rope drum. Wire rope winding in helical grooves on the drum is reeved over sheaves in the upper block and lower hook block for additional mechanical advantage. Limit switches are provided to stop the motors when limits of travel are reached. Current is brought to the crane by sliding or rolling collectors in contact with conductors attached to or parallel with the runway and preferably located at the cab end of the crane. Current from the runway conductors and cab is carried to the trolley in a like manner from conductors mounted parallel to the bridge girder. Festooned multiconductor cables are also used to supply current to crane or trolley. Electric cranes are built for either alternating or direct current, with the former predominating. The motors for both kinds of current are designed particularly for crane service. Direct-current motors are usually series-wound, and ac motors are generally of the wound-rotor or two-speed squirrel-cage type. The usual ac voltages are 230 and 460, the most common being 460. Variable-frequency drives (VFDs) are used with ac squirrel cage motors to provide precise control of the load over a wide range of speeds. Cranes and hoists equipped with VFDs are capable of delicate positioning and swift acceleration of loads to the maximum speed. Standard, inexpensive squirrel cage motors may be used with VFDs to provide high-performance control of all crane motions. The capacities and other dimensions for standard electric cranes Gantry Cranes Gantry cranes are modifications of traveling cranes and are generally used outdoors where it is not convenient to erect on overhead runway. The bridge (Fig. 10.4.14) is carried at the ends by the legs a, supported by trucks with wheels so that the crane can travel. As with the traveling crane, the bridge carries a hoisting unit; a cover to protect the machinery 9
from the weather is often used. The crane is driven by motor b through a gear reduction to shaft c, which drives the vertical shafts d through bevel gears. Bevel- and spur-gear reductions connect the axles of the wheels with shafts d. Many gantry cranes are built without the cross shaft, employing separate motors, brakes, and gear reducers at each end of the crane. Gantry cranes are made in the same sizes as standard traveling cranes. Special-Purpose Overhead Traveling Cranes A wide variety can be built to meet special conditions or handling requirements; examples are stacker cranes to move material into and out of racks, wall cranes using a runway on only one side of a building, circular running or pivoting cranes, and semi-gantries. Load-weighing arrangements can be incorporated, as well as special load-handling devices such as lifting beams, grapples, buckets, forks, and vacuum grips. Rotary Cranes and Derricks Rotary cranes are used for lifting material and moving it to points covered by a boom pivoted to a fixed or movable structure. Derricks are used outdoors (e.g., in quarries and for construction work), being built so that they can be easily moved. Pillar cranes are always fixed and are used for light, infrequent service. Jib cranes are used in manufacturing plants. Locomotive cranes mounted on car wheels are used to handle loads by hook or bulk material by means of tubs, grab buckets, or magnets. Wrecking cranes are of the same general type as locomotive cranes and are used for handling heavy loads on railroads. Locomotive Cranes The locomotive crane (Fig. 10.4.17) is self-propelled and provided with trucks, brakes, automatic couplers, fittings, and clearances which will permit it to be used or hauled in a train; it can function as a complete unit on any railroad. Locomotive cranes are of the rotating-deck type, consisting of a hinged boom attached to the machinery deck, which is turntable-mounted and operated either by mechanical rotating clutches or by a separate electric or hydraulic swing motor. The boom is operated by powered topping line, with a direct-geared hoisting mechanism to raise and lower it. Power to operate the machinery is deck-mounted, and the machinery deck is completely housed. The crane may be powered by internal-combustion engine or electric motor. The combination of internal-combustion engine, generator, and electric motor makes up the power arrangement for the diesel-electric locomotive crane. Another power arrangement is made up of internal-combustion engines driving hydraulic pumps for hydraulically powered swing and travel mechanisms. The car body and machinery deck are ballasted, thereby adding stability to the crane when it is rotated under load. The basic boom is generally 50 ft (15 m) in length; however, booms range to 130 ft (40 m) 10
in length. Locomotive cranes are so designed that power-shovel, piledriver, hook, bucket, or magnet attachments can be installed and the crane used in such service. Locomotive cranes are used most extensively in railroad work, steel mills, and scrap yards. The cranes usually have sufficient propelling power not only for the crane itself, but also for switching service and hauling cars. Truck Cranes The advent of the truck crane has changed significantly the methods of lifting and placing heavy items such as concrete buckets, logs, pipe, and bridge or building members. Truck cranes can, without assistance, be rapidly equipped with accessory booms to reach to 260 ft (79 m) vertically—or 180 ft (55 m) vertically with 170 ft of horizontal reach.
luffing mechanism The word luffing, like so many crane-related terms, has its origin and natural usage from the days of sailing ships. Booms were rated to handle cargo as well as sails, and the technologies of hoisting and season ship developed together. As using Crane practice, luffing means changing the angle of the main load supporting member makes with the horizontal. Other names used for the same ocean include topping, derricking, and booming. Henceforth, these terms can be used interchangeably. Derricking also raises and lowers loads to a limited extent, but mainly this motion serves to move load horizontally. Together with this swing, or horizontal rotating motion, luffing enables a hoisting the device’s service loads with a portion of vertical cylindrical zone. The derricking lines always carry system debt load and suffer an increase in loading whenever hook load is lifted. Nonetheless, the luffing system ropes. Less severe service then do hoisting system ropes as rule. Luffing is a relatively slow operation. It well-planned insulation will be arranged keep luffing movements at a minimum for the sake of production efficiency. This implies that the luffing ropes will undergo most of their loading sequences while static, his condition that the ropes are far better able to endure the loaded passage over sheaves. As with the hoisting mechanism, when the topping lift is static, each part of the line is equally loaded. When derricking starts, friction is introduced and the resulting losses can be taken.
11
An unloaded strut may not have enough way to overcome resistance and derrick out when required. The overhaul weight must serve to ensure that system will be able derrick out. The forces which resist derricking out and which must be overcome are the same as for the load hoist system but of course are now the forces in the derricking system. There are friction at the sheaves and at the derrick and drum and the weight of the vertical segment of lead rope. The overhaul weight calculated for the load hoist system will often be adequate for the derricking system as well; it is a question of system geometry. *A level-luffing crane is a crane mechanism where the hook remains at the same level whilst luffing; moving the jib up and down, so as to move the hook inwards and outwards relative to the base.[1] Some types of crane are inherently level-luffing: those with a fixed horizontal jib, such as gantry, hammerhead or the fixed-jib tower cranes commonly used in construction. Usually though, the description is only applied to those with a luffing jib that have some additional mechanism applied to keep the hook level when luffing. Level-luffing is most important when careful movement of a load near ground level is required, such as in construction or shipbuilding. This partially explains the popularity of fixed horizontal jibs in these fields. Toplis cable luffing
Stothert & Pitt crane with Toplis gear An early form of level-luffing gear was the "Toplis" design, invented by a Stothert & Pitt engineer in 1914.[2][3] The crane jibs luffs as for a conventional crane, with the end of the jib rising and falling. The crane's hook is kept level by automatically paying out enough extra cable to compensate for this. This is also 12
a purely mechanical linkage, arranged by the reeving of the hoist cables to the jib over a number of pulleys at the crane's apex above the cab, so that luffing the jib upwards allows more free cable and lowers the hook to compensate. Powered level-luffing As cranes and their control systems became more sophisticated, it became possible to control the level of luffing directly, by winching the hoist cable in and out as needed. The first of these systems used mechanical clutches between luffing and hoist drums, giving simplicity and a "near level" result. Later systems have used modern electronic controls and quickly reversible motors with good slow-speed control to the hoist winch motors, so as to give a positioning accuracy of inches. Some early systems used controllable hydraulic gearboxes to achieve the same result, but these added complexity and cost and so were only popular where high accuracy was needed, such as for shipbuilding.
Slewing Mechanism The slewing drive is a gearbox that can safely hold radial and axial loads, as well as transmit a torque for rotating. The rotation can be in a single axis, or in multiple axes together. Slewing drives are made by manufacturing gearing, bearings, seals, housing, motor and other auxiliary components and assembling them into a finished gearbox. History[edit] The slewing drive is a modernized take on the worm drive mechanism that dates back many centuries and was widely used during the Renaissance Era. Pappus of Alexandria(3rd century AD), a Greek mathematician is credited for an early version of the endless screw, which would later evolve into the worm drive. This mechanism was also used by Leonardo da Vinci as a component in many of his designs for machines. It can also be found in the notebooks of Francesco di Giorgio of Siena.] Many slewing drive concepts found prominence with the emergence of larger scale construction and engineering in the height of the Greek and Roman Empires. Technology
13
Traditional worm gear with a 4-start worm. Slewing drives function with standard worm technology, in which the worm on the horizontal shaft acts as the driver for the gear. The rotation of the horizontal screw turns a gear about an axis perpendicular to the screw axis. This combination reduces the speed of the driven member and also multiplies its torque; increasing it proportionally as the speed decreases. The speed ratio of shafts depends upon the relation of the number ofthreads on the worm to the number of teeth in the worm wheel or gear As technology has improved, more and more slewing drives are now functioning with hourglass worm technology which functions much in the same way as a traditional worm with one big exception: a traditional worm touches just one tooth at a time while an hourglass engages up to 11 teeth at one time.[5] This increased tooth engagement results in far greater strength, efficiency and durability. Performance characteristics Because of their multiple uses, slewing drives come in a variety of model sizes, performance ranges and mounting characteristics. The drives are perfect for applications that require both load holding and rotational torque from the same gear box. They can also be made with dual axes of rotation, (turning axes at the same time) or with dual drives on the same axis, (two worm threads driving the same ring gear in one axis Materials The specifications for drives and gears varies depending on the material the gear is composed of. However, a majority of the drives and gears commonly used are composed of steel and phosphor bronze. According to an extensive series of tests by the Hamilton Gear & Machine Co., chill-cast nickel-phosphor bronze ranked first in resistance to wear and deformation. Number two on the list was SAE No. 65 bronze. For bronze gears a good casting should have the following minimum physical characteristics:
14
15
Gantry Cranes Gantry cranes, bridge cranes, and overhead cranes, are all types of cranes which lift objects by a hoist which is fitted in a hoist trolley and can move horizontally on a rail or pair of rails fitted under a beam.An overhead travelling crane, also known as an overhead crane or as a suspended crane, has the ends of the supporting beam, the gantry, resting on wheels running on rails at high level, usually on the parallel side walls of a factory or similar large industrial building, so that the whole crane can move the length of the building, while the hoist can be moved to and from across the width of the building. A gantry crane or portal crane has a similar mechanism supported by uprights, usually with wheels at the foot of the uprights allowing the whole crane to traverse. Some portal cranes may have only a fixed gantry, particularly when they are lifting loads such as railway cargoes that are already easily moved beneath them. Overhead crane and gantry crane are particularly suited to lifting very heavy objects and huge gantry cranes have been used for shipbuilding where the crane straddles the ship allowing massive objects like ships' engines to be lifted and moved over the ship. Two famous gantry cranes built in 1974 and 1969 respectively, are Samson and Goliath, which reside in the largestdry dockin the world in Belfast,Northern Ireland. Each crane has a span of 140 metres and can lift loads of up to 840tonnesto a height of 70 metres, making a combined lifting capacity of over 1,600 tonnes, one of the largest in the world.However; gantry cranes are also available running on rubber tyres so that tracks are not needed, and small gantry cranes can be used in workshops, for example for lifting automobile engines out of vehicles.Samson and Goliath are now retained in Belfast as historic monuments under Article 3 of the Historic Monuments and Archaeological Objects (Northern Ireland). A ship-to-shore rail mounted gantry crane is a specialised version of the gantry crane in which the horizontal gantry rails and their supporting beam are cantilevered out from between frame uprights spaced to suit the length of a standard freight container, so that the beam supporting the rails projects over a quay side and over the width of an adjacent ship allowing the hoist to lift containers from the quay and move out along the rails to place the containers on the ship.
1
The uprights have wheels which run in tracks allowing the crane to move along the quay to position the containers at any point on the length of the ship. The first versions of these cranes were designed and manufactured by Paceco Corporation. They were called Portainers and became so popular that the term Portainer is commonly used as a generic term to refer to all ship-to-shore rail mounted gantry cranes.
Workstation gantry carnes Workstation gantry cranes are used to lift and transport smaller items around a working area in a factory or machine shop. Some workstation
2
gantry cranes are equipped with an enclosed track, while others use an I-beam, or other extruded shapes, for the running surface. Most workstation gantry cranes are intended to be stationary when loaded, and mobile when unloaded. Workstation Gantry Cranes can be outfitted with either a Wire Rope hoist as shown in the above hoist picture or a lower capacity Chain Hoist. Rail mounted gantry (RMG)
3
Rail mounted gantry cranes (RMG) are commonly found in factory applications such as steel yards, paper mills or locomotive repair shops. The EOT gantry crane functions similarly to an overhead bridge crane, but has rails installed on the ground and gantry-style legs to support the crane. Capacities range from 2 to 200 tons, and sometimes even greater capacities. Most are electrically powered and painted safety yellow.When bridge cranes and gantry cranes became more popular in factories in the late 1800s a steam engine was sometimes used as a way to power these devices. The lifting and moving would be transferred from a fixed line.
4
JIB CRANES INTRODUCTION TO JIB CRANES These cranes are characterized by the jib which is nothing but a long cantilever.Such cranes consist essentially of a horizontal member called the jib supported by a rope or cable or some type of structural member attached to a vertical mast or frame.Load is usually suspented from the other end of this mast.The cross section of this jib is an ‘I’ channel.This ‘I’ channel carries hoist,trolley which travels on this channel popularly known as guide rails.Depenting on the mounting jib cranes are classified into various types.
The link ed image cannot be display ed. The file may hav e been mov ed, renamed, or deleted. Verify that the link points to the correct file and location.
Jib Cranes consist of a horizontal load supporting boom, which is attached to a pivoting vertical column that is either free standing or building mounted. They enable lifting and lowering of a load within a fixed arc of rotation. Jib Cranes can be provided in a variety of capacities and configurations including motorized rotation. Below are the basic types of Jib Cranes.
Application: Free Standing series jib cranes: • Are easy to install • Perform a multitude of functions within a work area • Allow for 360º of continuous rotation even when using electric- or air-powered hoists and trolleys • Cantilever-style boom allows for maximum hoist lift • Puts no stress on its building’s support structure (all the force of the crane is supported by its foundation). FS series jibs are an ideal way to handle and transfer materials, and can be used to: • Service an open area without being tied to a building structure • Supplement a bridge crane • Service an area where a bridge crane is not available or feasible • Take the place of a wall or column mounted crane when less than 360º of rotation is sufficient, but no other structure is available for support 1
Two key requirements must be met before selecting a Free Standing Series jib crane: 1. The jib crane, in all cases, must be supported by a structurally adequate foundation. 2. There must be sufficient clearance above the boom (nominally 3 inches) throughout its arc
Application: • Ideal for moving loads around corners or through doorways • Use for reaching loads into machines or swinging loads under obstructions • Can be used with hook mounted lifting devices • Circular coverage areas
This image cannot currently be display ed.
This image cannot currently be display ed.
Description: Jib cranes are not created equally. Gorbel offers the most comprehensive features and design criteria in the
2
industry. Properly applied Gorbel® jib cranes: • Cover circular (or semi-circular) work areas • Are versatile enough to perform a wide variety of local handling and spotting functions • Are economical enough to be dedicated to individual work stations • Can increase worker satisfaction and encourage safe work practices • Provide a rapid return on investment
• Can be a useful addition to an overhead handling system, providing coverage in areas not efficiently serviced by a main crane • Can relieve a main crane of many handling operations where the greater capacity and energy consumption of the larger unit would be wasted • Can be effectively applied in the absence of a main crane, especially where load handling is localized • Are an economical choice for outdoor installations Gorbel manufactures three basic categories of jib cranes: 1. I-beam jib cranes (models FS300, FS350, FS350S, WB100, WC200, MT400 & MT450) 2. Enclosed track jib cranes (models WSJ200, WSJ360, TSJ50 & TSJ150) 3. Articulating jib cranes (models AJ360-F, AJ360-C, AJ200 & PPRO) Each category of crane possesses specific advantages and characteristics to cover all types of applications. All of Gorbel’s cranes are designed for deflection, as well as for stress, which minimizes bounce, deflection, and the effort required to move a trolley. Several manufacturers design only for stress. Gorbel’s standard, pre-engineered jib cranes are available in capacities from 50 pounds (23 kg) to 5 tons (4536 kg); please consult Gorbel if higher capacities or non-standard designs are required.
Applications: The following are just a few of the infinite number of uses for a Gorbel® jib crane: • In work cells to provide localized material handling • To supplement a large overhead crane system • Where overhead cranes are not possible (due to lack of adequate building supports, etc.) • To transfer materials from one work cell to another • For suspension of tools • For economical application outdoors Warning: Equipment described herein is not designed for, and should not be used for, lifting, supporting, or transporting humans. Failure to comply with any one of the limitations noted herein can result in serious bodily injury, death, and/or property damage.
Considerations for Selecting a Jib Crane: A careful analysis must be performed to determine how the crane will affect the efficiency of the work area and how it will be used in daily operation. The following are the most important considerations when selecting a crane: • The type and extent of the structural support available • Current and anticipated requirements for powered operation of the hoist or crane • The characteristics and design of each crane type • The overall height and height under boom offered • The overall cost of installation
The various types of jib cranes are: 3
•
Floor mounted jib crane 1. Fixed column jib crane 2. Rotating column jib crane
•
Wall mounted jib crane
•
Roof mounted jib crane
FLOOR MOUNTED JIB CRANE
These are cranes in which mast is attached to the ground.
The free standing Major jib crane has proven itself over 10,000 times! It is the world’s best selling jib crane for indoor and outdoor applications. This crane can be used in nearly every workstation: for feeding machine tools, in stockyards, in power plants, steelworks, machine houses or sewage treatment plants. Thanks to its very extensive list of accessories, the Major model can be equipped to handle all requirements, even up to those of an independently operated automatic crane.
4
Features • DIN 15018 hoisting class: H2 • DIN 15018 loading group: B3 • Medium-heavy design • Installation location: indoor / outdoor • Rotation with electrical pneumatic • Suitable for explosion protection with ATEX • Low-headroom cantilever design for efficient motorization possible large lifting height
5
The free standing Boss jib crane is helpful in more than just everyday applications in crane and lifting technology. These sophistically engineered jib cranes are used not only in stockyards, power plants, smelting plants and foundries, but also on mining excavators and dredgers. The Boss jib crane is designed and built for the toughest, most difficult jobs. Features • Classification according to DIN 15018 depending on mode of application and location of use • Installation location: indoor / outdoor • Rotation with electrical pneumatic motorization possible
Fixed column jib crane 6
In this type mast is stationary but jib may be stationary or rotatory.The load is raised by hoisting trolley and can be moved along the jib and can be rotated in a horizontal plane.
Rotating column jib crane In this type of crane everything is same as that of fixed column jib crane .Only exception is that the mast is rotating.This mast can rotate through 360 degee with whole jib and trolley.As seen from the figure it is clear that the column is mounted on the floor and it is pivoted at the bottom and top at the roof for provide support.
ROOF MOUNTED JIB CRANE
ElectroMech manufactures Single Girder as well as Double Girder cranes in the Underslung version as well. Such cranes find applications where the headrooms available are limited or
7
the process requirements cannot allow any other means of supporting the crane other than from the roof. Majority of the Underslung Overhead Cranes are in the capacity range from 250kg to 10MT. However, higher capacity Underslung Cranes can also be manufactured as per the client requirements. Hoisting is done using the standard ABUS Electric Chain Hoist /Wire Rope Hoist. Precise control of the up/down motion and/or travel motion can be achieved by fitting Variable Frequency Drives in the panels (optional). Control can be either through a Pendant Push Button station or a Radio Remote Control (optional). ElectroMech manufactures Single Girder Overhead Cranes in SWLs ranging from 250kg to 20MT in different configurations. Beam/Box type main girders (dependent on spans) These cranes can be offered either with an Electrically Operated Trolley (EOT) or a Hand Operated Trolley (HOT) depending on the client requirement. The standard range of ABUS Electric Wire Rope Hoists is used on these cranes. Alternatively, we can also supply these cranes with ABUS Electric Chain Hoists. Precise control of the up/down motion and/or travel motion can be achieved by fitting Variable Frequency Drives in the panels (optional). Control can be either through a Pendant Push Button station or a Radio Remote Control (optional). Additionally, we can also supply Single Girder Cranes in a ‘torsion box' type arrangement, featuring a cantilevermounted ABUS hoist.
Advantages:can save floor area,work span is large,can lift heavy weights
Disadvantages:roof must have high strength,risk of falling load
8
WALL MOUNTED JIB CRANE The link ed image cannot be display ed. The file may hav e been mov ed, renamed, or deleted. Verify that the link points to the correct file and location.
In this type the jib is provided pivot at the one end on the wall.Another pivot is attached at the end of the tension member.The whole jib can turn or rotate about these pivots.This can rotate upto 150 degree in practical.The walls need to be strength to take the load of crane. D-AW wall-mounted slewing jibs are suitable for universal applications in the lower load range up to 2000 kg. The low deadweight makes it easy to move the jib even under load. Thanks to their low headroom dimension, they can also be used wherever long hook paths are needed in spite of a low ceiling height. ■ Classifi cation according to DIN 15018 H2B2 ■ Fitted with Demag chain hoist as standard ■ I-beam profi le jib Options ■ Wall bracket to accommodate the two bearing brackets of the jib ■ Pillar bracket ■ Chain hoist with electric travel ■ Slewing motion limit stops ■ Locking arrangement for the jib ■ Low-maintenance fl at-cable festoon power supply ■ Control travelling separately along the jib ■ Radio control ■ Equipment for outdoor operation
D-MOS mobile pillar-mounted slewing crane (up to 500 kg) Ideally suited for workplaces that are subject to frequent change, since the crane is easily adapted to new requirements, or can be simply relocated together with the workplace. The location of the crane can be ideally adapted to the process requirements of the given application. D-MOS cranes are also highly suitable for maintenance or conversion work. 9
KBK pillar-mounted slewing jib crane (up to 1000 kg) KBK slewing cranes feature high load capacities and outreach in relation to their deadweight. The low weight enables the jib to be moved easily and the use of KBK hollow section rail as the crane girder provides for very low travel forces. KBK pillar-mounted slewing jib cranes are also available in low-headroom design The low headroom dimension results in a lifting height gain of 290 mm compared to the standard design. Whether for low-headroom applications, modernisation measures or changes in the use of the building, our "short" units are the perfect solution in many cases. KBK pillar-mounted slewing crane with two jibs (up to 1000 kg) Effective solution as a pillar-mounted slewing crane with two jibs for the same space requirement as slewing cranes with one jib. Four different jib arrangements are available for the perfect workplace design. The efficiency of specific process sequences can be improved and, at the same time, implemented economically. D-AS pillar-mounted slewing jib crane (up to 2000 kg) The light-weight design and low-headroom jib make this pillar-mounted slewing jib crane suitable for universal applications in the medium load range up to 2000 kg. D-GS pillar-mounted slewing crane (up to 1000 kg) Pillar-mounted slewing cranes offer a significant advantage wherever movement of the jib is not inhibited by walls, columns or similar obstacles: the slewing range covers n x 360°. D-GS pillar-mounted slewing cranes for loads weighing up to 1000 kg feature particularly low headroom and compact dimensions. They are ideally suited wherever maximum hook paths are required and only limited headrom is available. D-TS pillar-mounted slewing crane (up to 5000 kg) This slewing crane is the universal solution for the medium load range up to 5000 kg. The low-headroom jib provides for particularly long hook paths. It can also be powered by an optional electric slewing drive for ease of operation. D-MS pillar-mounted slewing crane (up to 10000 kg)
10
This pillar-mounted slewing crane features a high load capacity for a long outreach. The low-headroom jib provides for particularly long hook paths. It can also be powered by an optional electric slewing drive for ease of operation. KBK wall-mounted slewing jib (up to 1000 kg) The decisive advantage of wall-mounted slewing jibs is that they require no floor space, since they are mounted on load-bearing concrete walls, pillars or machinery and installations. They are particularly easy to install, since the bracket is ready to be fitted as a unit and eliminates any complicated alignment work. KBK wall-mounted slewing jibs are suitable for the lower load range up to 1000 kg. KBK wall-mounted slewing jibs are also available in low-headroom design The low headroom dimension results in a lifting height gain of 290 mm compared to the standard design. Whether for low-headroom applications, modernisation measures or changes in the use of the building, our "short" units are the perfect solution in many cases. D-AW wall-mounted slewing jib (up to 2000 kg) D-AW wall-mounted slewing jibs are suitable for universal applications in the lower load range up to 2000 kg. The low deadweight makes it easy to move the jib even under load. Thanks to their low headroom dimension, they can also be used wherever long hook paths are needed in spite of a low ceiling height. D-GW wall-mounted slewing jib (up to 10000 kg) Designed for use with Demag chain hoists or Demag rope hoists in connection with their low-headroom jib and high load capacity, D-GW wall-mounted
11
slewing jibs are suitable for a wide variety of applications
Description: • Combines high quality, safety, stringent design criteria, ease of installation, and ease of rotation • Consists of an I-Beam for the mast and boom, two fabricated rotating brackets that bolt to the structural support, and trolley stops • Mounts to a wall or column • Provides approx. 200º of rotation The WC200 series provides a versatile and cost-effective solutions to your crane needs. All fittings are made of structural steel and are manufactured to avoid reliance upon castings. Mast/boom connections are designed for maximum shipping economy and ease of installation.
Application: • Similar in use to the wall bracket jib crane, but has the advantage of allowing maximum hoist lift • Can be installed close to the underside of the lowest overhead obstruction (nominally a minimum of 3 inches) • Especially desirable for individual use in bays, along walls, and sides of shops, or as a supplement to a traveling overhead crane or monorail Two key requirements must be met before selecting a Wall Cantilever series jib crane: 1. There must be a structurally adequate wall, column, or truss to support the crane. Note: Responsibility for determining if the support is adequate rests entirely on the customer. Information on the loading of the support by the crane can be found in the WC200 pricing section under the column labeled “Thrust & Pull.” 2. There must be sufficient clearance above the boom (nominally a minimum of 3 inches) throughout its arc.
Spans & Capacities: The Wall Cantilever jib cranes are available in capacities up to 5 tons, with standard boom spans up to 30 feet. Please contact the Gorbel® Customer Service Department at (800) 821-0086 (US and Canada) or (585) 924-6262 (outside US) for information regarding larger spans or capacities, or for special requirements not in the product binder. Questions? Concerns?
12
Advantages: leave the floor space open, take heavy loads,rotation is possible
Disadvantages: walls need to be strengthen to take the load of crane
13
Slewing Mechanism The term "slewing drive" most often refers to a mechanism that consists of a radial gear, an axial shaft called a worm, and a connected driving component. More advanced slew drives might include specific worm designs, protective enclosures and other auxiliary components. Slewing drives are capable of transferring forces and torque as well as sustaining those forces over time. There are many applications for slewing drives, a few different materials to choose from, and a long history.
The most basic slewing drive has a radial gear driven by the worm. The teeth of the gear meet with the grooves in the worm and, as the worm turns, the gear also turns. Common features for different slewing drives can include an hourglass-shaped worm, which is often considered more efficient because multiple teeth on the gear can be engaged at once. Other features can include a protective enclosure meant to keep the mechanisms clean. The motor or driving component, like the spinning of a wind turbine, also might change the specific design of a slewing drive.
In general, the purpose of these machines is to change axial movement to radial movement. Depending on the number of threads on the worm and the number of teeth on the gear, the speed and power of the axial force will be converted to a specific radial force. Depending on the application, a slewing drive might be useful for amplifying the torque that rotates a mechanism. A slewing bearing is a piece of hardware used to facilitate circular movement, usually of a large device such as a crane. The term "slew" means to turn without changing location, so a slewing bearing is one that will not move out of place but will instead facilitate movement while in one position. These bearings are usually quite large and are used for heavy-duty applications; they are therefore usually made from heavy-duty metals such as steel, though other materials including aluminum and titanium can be used for their construction as well.
The slewing bearing is not mounted on a shaft, but is instead bolted to a flat surface. The gears allow one part of the bearing to move while the other stays 1
in place, thereby facilitating movement. The path of the movement can vary; sometimes the slewing bearing is used to facilitate round movement, while in other cases an oscillating movement can be performed. The type of movement depends on the configuration of the slewing bearing as well as the location of the gears. The gears allow a platform to be driven in a certain motion, and the location of the gears will depend on the design of the device.
Movements of a cranes 2
Jib crane have the following motions: 1. 2. 3. 4.
Hoisting motion Derricking or luffing motion Slewing motion Long travel motion Hoisting motion: It is used to lift or lower the load. This is usually achieved by steel wire ropes being affixed to a crane hook or a grab hanging from the outer end of the jib. The rope is applied through some receiving arrangement and controlled and operated by a winch system.
Derricking or Luffing motion: It is imparted to the inclined member or the jib to move in a vertical plane so that the angle of the jib may be changed in order to bring the load line nearer to or further off from the centre of the crane.
3
Slewing motion: It is imparted to the whole super structure of the crane including the jib, so that it can turn about a central pivot shaft with respect to the non-revolving parts. This motion enables the crane to shift the load line to revolve round the crane.
4
Long Travel Motion: It may be required when the whole crane structure has to be shifted to a distant place along a rail track or along a road. Travelling is different from crane to crane only in that a disproportionately heavy crane requires disproportionately heavy track and that a wide crane requires an inconveniently wide track.
5
6
•
Back tension in sprockets
First, let us explain the relationship between flat belts and pulleys. Figure 2.5shows a rendition of a flat belt drive. The circle at the top is a pulley, and the belt hangs down from each side. When the pulley is fixed and the left side of the belt is loaded with tension (T0), the force needed to pull the belt down to the right side will be: T1 = T0 × eµθ For example, T0 = 100 N: the coefficient of friction between the belt and pulley, µ = 0.3; the wrap angle θ = π (180°). T1 = T0 × 2.566 = 256.6 N In brief, when you use a flat belt in this situation, you can get 256.6 N of drive power only when there is 100 N of back tension. For elements without teeth such as flat belts or ropes, the way to get more drive power is to increase the coefficient of friction or wrapping angle. If a substance, like grease or oil, which decreases the coefficient of friction, gets onto the contact surface, the belt cannot deliver the required tension. In the chain's case, sprocket teeth hold the chain roller. If the sprocket tooth configuration is square, as in Figure 2.6, the direction of the tooth's reactive force is opposite the chain's tension, and only one tooth will receive all the chain's tension. Therefore, the chain will work without back tension.
Figure 2.5 Flat Belt Drive
1
Figure 2.6 Simplified Roller/Tooth Forces
Figure 2.7 The Balance of Forces Around the Roller
But actually, sprocket teeth need some inclination so that the teeth can engage and slip off of the roller. The balance of forces that exist around the roller are shown in Figure 2.7, and it is easy to calculate the required back tension. For example, assume a coefficient of friction µ = 0, and you can calculate the back tension (Tk) that is needed at sprocket tooth number k with this formula: Tk = T0 × {sin ø ÷ sin (ø + 2β)}
k-1
Where: •
Tk = back tension at tooth k
•
T0 = chain tension
•
ø = sprocket minimum pressure angle 17 - 64/N(°)
•
N = number of teeth
•
2β = sprocket tooth angle (360/N)
•
k = the number of engaged teeth (angle of wrap × N/360); round down to the nearest whole number to be safe
By this formula, if the chain is wrapped halfway around the sprocket, the back tension at sprocket tooth number six is only 0.96 N. This is 1 percent of the amount of a flat belt. Using chains and sprockets, the required back tension is much lower than a flat belt. Now let's compare chains and sprockets with a toothed-belt back tension. Although in toothed belts the allowable tension can differ with the number of pulley teeth and the revolutions per minute (rpm), the general recommendation is to use 1/3.5 of the allowable tension as the back tension (F). This is shown in Figure 2.8. Therefore, our 257 N force will require 257/3.5 = 73 N of back tension.
2
Both toothed belts and chains engage by means of teeth, but chain's back tension is only 1/75 that of toothed belts.
Figure 2.8 Back Tension on a Toothed Belt
3
GANTRY CRANES Material handling is one of the key phenomena in any industrial environment. The mechanical device o be adopted for such handling depends upon a number of factors such as weight of the materials, distance to be handled, frequency and repetitiveness of handling, economy of time and cost, safety and the process of manufacturing. An environment of high degrees of temperature and distancing away from such environment is another aspect that necessitates handling of materials through overhead cranes. There are a number of major industrial segments that depend upon the deployment of Overhead cranes. They are Paper Mills, Steel Plants, Sugar Mills, Cement Plants, Chemical Sector and Railways. An overhead crane, also called a bridge crane operating over the working environment, runs horizontally over two parallel runways coupled to a traveling bridge. The lifting component, hoist travels along the bridge to lift materials. It covers varying span, depending upon the various processes involved in manufacturing. The basic objective of using overhead crane is to keep the hazardous elements such as heat, acidity, combustibility, distanced from the work force. For example, in a galvanizing unit, heavy structural materials are required to be dipped into a number of tanks for the performance of sequential processes such as acid tank for pickling, water tank for rinsing, chemical tank for fluxing and molten zinc tank for galvanizing. Similarly, in a steel plant, overhead crane does operations like feeding of raw materials to a furnace, storing for cooling, lifting and loading of finished coils onto trucks and trains. Gantry cranes, bridge cranes, and overhead cranes, are all types of cranes which lift objects by a hoist which is fitted in a hoist trolley and can move horizontally on a rail or pair of rails fitted under a beam. An overhead travelling crane, also known as an overhead crane or as a suspended crane, has the ends of the supporting beam, the gantry, resting on wheels running on rails at high level, usually on the parallel side walls of a factory or similar large industrial building, so that the whole crane can move the length of the building, while the hoist can be moved to and from across the width of the building. A gantry crane or portal crane has a similar mechanism supported by uprights, usually with wheels at the foot of the uprights allowing the whole crane to traverse. Some portal cranes may have only a fixed gantry, particularly when they are lifting loads such as railway cargoes that are already easily moved beneath them.
1
Types of gantry cranes
Container crane
A ship-to-shore rail mounted gantry crane is a specialized version of the gantry crane in which the horizontal gantry rails and their supporting beam are cantilevered out from between frame uprights spaced to suit the length of a standard freight container, so that the beam supporting the rails projects over a quayside and over the width of an adjacent ship allowing the hoist to lift containers from the quay and move out along the rails to place the containers on the ship. The uprights have wheels which run in tracks allowing the crane to move along the quay to position the containers at any point on the length of the ship. The first versions of these cranes were designed and manufactured by Paceco Corporation They were called Portainers and became so popular that the term Portainer is commonly used as a generic term to refer to all shipto-shore rail mounted gantry cranes.
Workstation gantry cranes 2
Workstation gantry cranes are used to lift and transport smaller items around a working area in a factory or machine shop. Some workstation gantry cranes are equipped with an enclosed track, while others use an I-beam, or other extruded shapes, for the running surface. Most workstation gantry cranes are intended to be stationary when loaded, and mobile when unloaded. Workstation Gantry Cranes can be outfitted with either a Wire Rope hoist as shown in the above hoist (device) picture or a lower capacity Chain Hoist.
Rail mounted gantry (RMG) cranes
3
Rail mounted gantry cranes (RMG) are commonly found in factory applications such as steel yards, paper mills or locomotive repair shops. The EOT gantry crane functions similarly to an overhead bridge crane, but has rails installed on the ground and gantry-style legs to support the crane. Capacities range from 2 to 200 tons, and sometimes even greater capacities. Most are electrically powered and painted safety yellow. When bridge cranes and gantry cranes became more popular in factories in the late 1800s a steam engine was sometimes used as a way to power these devices. The lifting and moving would be transferred from a fixed line shaft. The picture on the right shows an example of system powered by a line shaft and steam engine. The overhead crane is from 1875, and was one of the first systems to be powered in such a way.
EOT (Electric Overhead Traveling) Crane This is most common type of overhead crane, found in most factories. As obvious from name, these cranes are electrically operated by a control pendant, radio/IR remote pendant or from an operator cabin attached with the crane itself.
4
Fixed Height This gantry crane has a beam fixed at a particular height. These cranes lift objects to specific heights. Some fixed-height gantry cranes are equipped with wheels or casters for moving around a factory. Portable fixed-height cranes prove useful in places where lifting is not frequently performed.
Adjustable Height
An adjustable-height gantry crane has grooves on the support beams; the horizontal beams fits into the grooves to adjust the hoist to reach varying heights. These gantry cranes are equipped with wheels or casters; they lift objects to different heights in construction and in other industries. Single Girder
5
A single-girder gantry crane lifts heavy objects in small manufacturing units and warehouses. These gantry cranes are equipped with wheels that can be fixed in different areas of a factory. The height of the hoist fastened under the girder in a single-girder gantry crane is lower than that of a double-girder crane. A single-girder gantry crane has lateral braces for added strength.
Double Girder
Double-girder gantry cranes are used in heavy industries; they carry heavier objects than the single-girder version. Double-girder gantry cranes have two horizontal beams with the hoist fastened between the two beams rather than under the horizontal beam. The hoist has a greater height than that of a singlegirder crane.
Cantilever Gantry Crane A cantilever gantry crane has girders that run crossways on one side of the horizontal girder or on both sides of the horizontal girder.
6
Portable Gantry Cranes
Portable gantry cranes are an ideal answer to awkward applications like hard to budge cartons or machinery. These cranes give you the pinpoint accuracy, speed, durability, and load control needed in many of the following industries and operations: automotive, trucking, manufacturing, loading docks, aircrafts, marine, warehouses or maintenance.
Advantages • • • • • •
Can be used where overhead runways are not practical. A much greater bridge weight than an equivalent overhead crane. Span upto 150m Less costly as compared to bridge crane Simpler installations Floor area is free
Disadvantages • • •
Accidents may occur Operation is slow Expensive 7
• •
High power consumption Structure needs to be very strong
Apron conveyors An apron conveyor is a type of conveyor made from individual apron plates that are linked together with hinges on its underside, thus creating a looped carrying surface where materials can be placed. It plays a vital part in several industries by being used to move different materials from one location to another. This type of conveyor is used to deliver a large number of materials across several phases of production and is particularly useful for transport of huge and heavy materials. Many industries consider apron conveyors to be a lifeline in their industry, including manufacturing, agricultural, and chemical industries. In the manufacturing industry, these conveyors are used to move materials across different sections during the manufacturing process; in the agricultural industry, they are used to deliver grains. Apron belts can be made to have walls that can ideal for moving materials with no containers, such as feed and gravel. In the chemical industry, apron belts are used to move hazardous materials that prevent workers from handling them.
8
An apron conveyor works much like the tracks of a battle tank. Individual apron plates overlap and are linked together to form a closed belt or chain. A mechanism, usually composed of several metal rollers, is placed inside the conveyor belt. Some rollers contain pins or teeth that hook into the holes or grooves built under the apron plates. When the rollers turn, the teeth that are hooked to the plates move, which then moves the apron conveyor belt along the rollers. This action is similar to when a sprocket moves a bicycle chain when the pedals are pushed. The operator can adjust the speed and direction of the conveyor through the mechanism. Since the apron conveyor belt forms a loop, it can work continuously as long as the roller mechanism turns. Apron conveyors made from high grade steel are useful for handling abrasive materials, such as rocks and granules. Walls and overlap in the apron plates ensure minimal material loss, especially when transporting grains and detritus. Mainly used for industrial purposes, these conveyors are made to withstand tremendous weight, heat, and continuous operation. The conveyor can be treated with special coatings to achieve a desired surface, such as friction or elasticity.
9
Parts of an apron conveyor The apron conveyor comprises of the following parts: 1. Frame Frame is usually welded of angle iron or channel bars. The terminal sections are separate frames accommodating the drive and take up units. The intermediate sections, supporting the moving parts of the conveyor consists of four to six meter long metal structures. The guide ways for the supporting rollers are made of angle iron and of channel or narrow gauge rail. 2. Drive Unit The driving unit of an apron conveyor consists of the driving sprockets, transmission gear and electric motor. Conveyors having an inclined or horizontal inclined path are provided with hold back brake to obviate the risk of a loaded belt sliding back when the current supplying the motor fails or a defect in the transmission gear fail to retain the loaded apron in position.
3. Take up Apron conveyors have screw or spring and screw take-ups mounted on the terminal sprockets. The takeup travel should not be less than 1.6 to 2.0 times the chain pitch. One of the take up pulleys is keyed to the shaft and the other is not to permit its adjustment to the chain joint position. 4. Apron Apron is the load carrying member of tha apron conveyor and is therefore, designated to suit the nature of the material conveyed. Apron comein the following basic designs: a. Flanged b. Unflanged c. Flat d. Spaced with rollers e. Spaced without rollers f. Corrugated g. Deep h. Box type i. Shallow
10
5. Pulling Member Apron conveyors are usually equipped with two strands to link plate bush roller chains. The travelling rollers of the extensively used bush roller chain support the apron and load along the guide ways of the conveyor. The roller may be flanged or unflanged , may run in sliding bearings or roller bearings. The latter are mainly used in heavy duty conveyors. Stationary rollers (idlers) secured on the conveyor frame support the apron of the conveyor frame support the apron of the conveyors employing bush, bush roller and detachable chains. On the loaded run the chain link edges slide on the stationary rollers while on the return the apron is supported like the belt conveyor.
Uses of apron conveyors Apron conveyors are used in conveying hot, sharp lump and piece of materials. They are widely used in chemical industry enterprises, metallurgy, coal mining, machine building and other branches of industry. They also serve to convey article pastwork stations in line production.
Advantages • • • • • • • •
They are able to handle heavy, large, lumped and hot materials They have capacity of 3000 tonnes per hour and over They run smoothly and noiselessly They may be fed from over head hoppers They follow a wide range of complex paths Can be adjusted to any length by changing the number of plates Maintenance and repair are easy Damaged plates can be easily removed and replaced.
Disadvantages • • • •
They are bulky and have considerable weight Continuous maintenance is required They have hinged joints Cannot be used in food industry as there is a risk of contamination 11
Working principle and Feature of Belt Conveyor Belt conveyor is a machine transporting material in a continuous way by friction drive. It is mainly composed by rack, conveyor belt, belt roll, tensioning device and gearing. It can form a material delivery process between the initial feeding point and the final discharging point of jaw crusher . It can transport not only granular material, but also work piece. Besides the pure material transporting, it can also form a rhythmic flow transport line complying with the requirements of various industrial production processes. The belt conveyor can be used for horizontal transportation or inclined transportation in a convenient way, and widely used in modern industrial enterprises, such as: mine tunnel, mine surface transportation system, open-pit and concentrator. Working principle Belt conveyor is composed by two endpoint pulleys and a closed conveyor belt. The pulley that drives conveyor belt rotating is called drive pulley or transmission drum; the other one–only used to change conveyor belt movement direction– is called bend pulley. Drive pulley is driven by the motor through reducer, and conveyor belt dragging relies on the friction drag between the drive pulley and the conveyor belt. The drive pulleys are generally installed at the discharge end in order to increase traction and be easy to drag. Material is fed on the feed-side and landed on the rotating conveyor belt, then rely on the conveyor belt friction to be delivered to
1
discharge Feature
end.
Compared with other transport equipment, such as Motorcycle, belt conveyor is the best efficient continuous coal transportation equipment with advantages of long transmission distance, large volume, continuous conveyor, etc., and operate reliably, easy to implement automation and centralization control; especially for high yield and efficient mine, belt conveyor has become the key equipment for coal mining and mechatronics technology. The belt conveyor mainly has the following characteristics: the body can flex easily with a belt-warehousing, the tail can elongate or shorten complying with the coal face; directly lay on the roadway floor without setting up foundation; compact structure, light and handy rack and convenient disassembly. When the transmission capacity is big or transport distance is far, we can meet the requirements by equipping with intermediate drives. According to the requirements of transmission process, it can be transported by single transmission and also can be formed a horizontal or inclined transportation by multi-unit. The belt conveyor is widely used in metallurgy, coal, transportation, utilities, chemical and other departments because of its features of big conveying capacity, simple structure, easy-to- maintenance, low cost and versatility. The belt conveyor is also used in building materials, electricity, light, food, ports, ships and other departments. 2
A conveyor belt is the carrying medium of a belt conveyor system (often shortened to belt conveyor). A belt conveyor system is one of many types of conveyor systems. A belt conveyor system consists of two or more pulleys (sometimes referred to as drums), with an endless loop of carrying medium - the conveyor belt - that rotates about them. One or both of the pulleys are powered, moving the belt and the material on the belt forward. The powered pulley is called the drive pulley while the unpowered pulley is called the idler pulley. There are two main industrial classes of belt conveyors; Those in general material handling such as those moving boxes along inside a factory and bulk material handling such as those used to transport large volumes of resources
and
agricultural
materials,
such
as grain, salt, coal, ore, sand, overburden and more. Today there are different types of conveyor belts that have been created for conveying different kinds of material available in PVC and rubber materials.
3
The belt consists of one or more layers of material. Many belts in general material handling have two layers. An under layer of material to provide linear strength and shape called a carcass and an over layer called the cover. The carcass is often a woven fabric having a warp & weft. The most common carcass materials are polyester, nylon and cotton. The cover is often various rubber or plastic compounds specified by use of the belt. Covers can be made from more exotic materials for unusual applications such as silicone for heat or gum rubber when traction is essential. Material flowing over the belt may be weighed in transit using a beltweigher. Belts with regularly spaced partitions, known as elevator belts, are used for transporting loose materials up steep inclines. Belt Conveyors are used in self-unloading bulk freighters and in live bottom trucks. Belt conveyor technology is
also
used
in conveyor
sidewalks or escalators,
as
transport such well
as
as moving on
many
manufacturing assembly lines. Stores often have conveyor belts at the check-out counter to move shopping items. Ski areas also use conveyor belts to transport skiers up the hill. 4
The Belt
The system's load capacity relies on the belt's centre chain. The chain is driven by the drive unit and it returns through the frame from the idler unit. This positive 210º sprocketwrapped drive withstands high pull forces and insures durability.
The slats are snapped onto the centre chain and can be replaced individually at the drive and idler unit without the need for special tools. The taps at the centre of the belt are enclosed along the frame's entire length including the return.
5
Because the belt is so well captured, the AmbaVeyor is able to convey loads in all directions and pass through bends without any problem. As a result, the AmbaVeyor conveyor has no tracking problems, even when side pushing products to and from the belt.
The TPO slats applied in the AmbaVeyor overlap each other and form a closed conveyor belt. This universal belt type is suitable for almost all applications. The slats can be fitted with a high friction top in order to transport along inclines. The grip is determined by the ratio of high friction to normal slats.
Performance The AmbaVeyor is capable of running at speeds of up to sixty metres per minute. The maximum belt length can vary from ten to fifty metres, depending on load and track layout. The belt moves on slide profiles around the centre and on the outer ends of each slat. This ensures stable support over the entire width. The load capacity can be up to 120 kg/metre, depending on the type of product to be conveyed.
6
TOPIC : CONVEYOR MACHINES – BELT CONVEYORSTYPES
CONVEYOR MACHINES: -
Mechanical conveyors are used for transporting most bulk solids (sand, ash, grains etc.) They are used not only in transportation of bulk solids from one location to another location but also for feeding, discharging, metering and proportioning such materials to and from bulk solids
-
storage silos and other solids handling and processing equipments. Conveyor is a device which is used for continuous transportation.
1
It can be used for horizontal or inclined conveying. Also vertical conveying as an elevator. They may be fixed or portable i.e (a) Portable conveyors (b) Straight conveyors (c) Circular conveyors - Conveyors which are driven with the help of power known as traction conveyors or those without the power known as tractionless conveyors as material moves due to gravity. Conveyors can be classified in the following ways : - Type of product being handled : unit load or bulk load. - Location of the conveyor : overhead, on-floor, or in-floor. - Whether or not loads can accumulate on the conveyor.
BELT CONVEYOR
A conveyor belt is the carrying medium of a belt conveyor system (often shortened to belt conveyor). A belt conveyor system is one of many types of conveyor systems. A belt conveyor system consists of two or more pulleys (sometimes referred to as drums), with an endless loop of carrying medium - the conveyor belt - that rotates about them. One or both of the pulleys are powered, moving the belt and the material on the belt forward. The powered pulley is called the drive pulley while the unpowered pulley is called the 2
idler pulley. There are two main industrial classes of belt conveyors; Those in general material handling such as those moving boxes along inside a factory and bulk material handling such as those used to transport large volumes of resources and agricultural materials, such as grain, salt, coal, ore, sand,overburden and more. Today there are different types of conveyor belts that have been created for conveying different kinds of material available in PVC and rubber materials. The belt consists of one or more layers of material. Many belts in general material handling have two layers. An under layer of material to provide linear strength and shape called a carcass and an over layer called the cover. The carcass is often a woven fabric having a warp &weft. The most common carcass materials are polyester, nylon and cotton. The cover is often various rubber or plastic compounds specified by use of the belt. Covers can be made from more exotic materials for unusual applications such as silicone for heat or gum rubber when traction is essential. Material flowing over the belt may be weighed in transit using a beltweigher. Belts with regularly spaced partitions, known as elevator belts, are used for transporting loose materials up steep inclines. Belt Conveyors are used in selfunloading bulk freighters and in live bottom trucks. Belt conveyor technology is also used in conveyor transport such as moving sidewalks or escalators, as well as on many manufacturing assembly lines. Stores often have conveyor belts at the check-out counter to move shopping items. Ski areas also use conveyor belts to transport skiers up the hill.
TYPES OF BELT CONVEYORS : 1) Flat Belt conveyor:
3
Flat Belt Conveyors are Belt Conveyors in which the carrying run is supported by flat-belt idlers or pulleys.To align a flat belt conveyor simply adjust the tail end pulley or the idler pulley, it is provided with adjuster bolt to adjust it in order to align the conveyor. Flat belt conveyors are best suited for handling cartoons, bags, sorting and picking component range, filing, labeling, inspection, packaging and wrapping tasks. 2) Troughed Belt conveyor:
Troughed belt conveyor is that in which the belt forms a trough on the carrying side while running over idler rollers which are either in set of 5 rolls, 3 rolls or 2 rolls. The troughing angle adopted are: 15°, 20° , 25° , 30° , 35° , 40° , 45° . Return idlers are usually straight roller type.
4
Transverse flexibility or rigidity of the belt is another significant consideration. It is important that the belt trough properly. The empty conveyor belt must make sufficient contact with the center roll in order to track properly.
Troughed belt conveyors are used for higher capacity, higher speed requirement, and for handling bulk material of large lump size. It suitable for inclined or declined type conveyors.
Transition distance is defined as the distance from the center line of the first fully troughed idler roll to the center line of either the head or tail pulley. The distance from the pulley to the top of the wing idler is certainly greater than the distance from the pulley to the center roll of the troughing set. If the transition distance is too short, the edge of the belt can be over stretched. This will adversely affect the load support and belt life. 3) Closed belt conveyor:
5
Self-enclosed conveyor belts (pipe, tube or hose conveyor belts) are primarily used where bulk materials must be conveyed along horizontal and vertical curves in confined spaces, and/or where the environment has to be protected resp. where spillage must be avoided. The belt can negotiate tight horizontal and vertical curves. This eliminates or reduces transfer points, which is a big cost saving. Inclinations of up to 35° can be dealt with. Pipe conveyor belts protect the conveyed material from external influences like rain and wind and protect the environment by avoiding spillage of the conveyed material. Even in the bottom run, no spillage will occur, because the carry side is inside of the tube. The idler supports can be spaced farther apart, because it is self-supporting. An additional conveyor cover is not necessary. Pipe conveyors are a German invention, first patented in 1954. Since a pipe conveyor belt has
to close and open at the head and drive pulley (or even at intermediate feeding stations), and
be closed at any position along the conveyor
for many years or decades, a sophisticated orthotropic carcass system is indispensable.
6
The belt must not flag so that the edge touches the conveyed material and it must not be too stiff, which would increase motor power resp. energy consumption and lead to premature wear of the belt and the idlers. The belt must always open and never overlap on the pulleys. The rubber covers must have enhanced specific properties that cope with the high stretch and with the effects of ozone and ultraviolet radiation. The belt width is approx. 4 times the pipe diameter 4) Metallic Belt conveyor:
More versatile than other types of conveyors, the steel belt conveyor can be used to handle any type of metal scrap -- from bushy material to chips and turnings, wet or dry -- in any volume, and in a wide variety of conveyor paths. It's capable of combining horizontal and elevating movements. Heavy-duty side frames, track and wear bars keep the belt on track shift after shift. Features •
Extended service life with replaceable bushings in heavy-duty side chain
•
Interlocking side wings for efficient conveying of small scrap pieces
•
Custom engineered to meet application requirements
Options 7
•
Round, square or open end configurations to meet application requirements
•
Plain, perforated or dimpled belting to meet application requirements
•
Drive can be mounted above, below or on the side of the conveyor
•
Custom skirts, chutes and hoppers to fit application requirements
•
Special side sections are available for height restrictions
•
Variable speed drive.
5) Portable conveyor:
Short length flat conveyors carried on a wheeled structure is termed portable conveyor.These are particularly useful for looking and unloading of trucks/transport vehicles. The inclination of the conveyor can generally be adjusted to suit application.
6) Chain/Rope driven belt conveyor :
8
A chain conveyor is a type of conveyor system for moving material through production lines. Chain conveyors utilize a powered continuous chain arrangement, carrying a series of single pendants. The chain arrangement is driven by a motor, and the material suspended on the pendants are conveyed. Chain conveyors are used for moving productsdown an assembly line and/or around a manufacturing or warehousing facility.[1] Chain conveyors are primarily used to transport heavy unit loads, e.g. pallets, grid boxes, and industrial containers. These conveyors can be single or double chain strand in configuration. The load is positioned on the chains, the friction pulls the load forward.[2] Chain conveyors are generally easy to install and have very minimun maintenance for users.[3]
9
Many industry sectors use chain conveyor technology in their production lines. The automotive industry commonly use chain conveyor systems to convey car parts through paint plants. Chain conveyors also have widespread use in the white and brown goods, metal finishing and distribution industries. Chain conveyors are also used in the painting and coating industry, this allows for easier paint application. The products are attached to an above head chain conveyor, keeping products off of the floor allows for higher productivity levels.
10
CONVEYOR BELTS A conveyor belt is the carrying medium of a belt conveyor system. A belt conveyor system is one of many types of conveyor systems. A belt conveyor consist of two or more pulleys or drums with an endless loop of carrying mediumthe conveyor belt- that rotates about them. One or both of the pulleys are powered, moving the belt and the material on the belt forward.
The belt consists of one or more layers of material. Many belts used in material handling have two layers. An under layer of material to provide linear strength and shape called carcass and an over layer called the cover. The carcass is often a woven fabric having a warp & weft. The most common carcass materials are polyester, nylon and cotton. The cover is often various rubber or plastic compounds specified by use of the belt. Covers can be made from more exotic materials for unusual applications such as silicone for heat or gum rubber when traction is essential.
1
Rubber conveyors are commonly used to convey items with irregular bottom surfaces (small items that would fall in between rollers). The belt is looped around each of the rollers and when one of the rollers is powered by an electrical motor, the belting slides across the solid metal frame bed, moving the product.
TYPES OF BELTS There are three types of conveyor belts : 1. Basic belt 2. Snake sandwich belt 3. Long belt A basic belt consists of two or more pulleys that hold one continuous length of material. These type of belts can be motorized or require manual effort. As the belt moves forward, all the items on the belt are carried forward. The snake sandwich conveyor consists of two separate conveyor belts that are set up parallel to each other and hold the product in place while moving along the belt. This type of 2
belt is used to move items up steep inclines, up to 90 degrees. Created in 1979, the snake sandwich conveyor was designed as a simple, efficient method of moving rocks and other material out of a mine. The long belt conveyor is a system of three drive units used to move materials over a long distance. The most important feature of this system is the ability of the rollers to handle both horizontal and vertical curves. The long belt conveyor system can reach up to 13.8 Km in length. This type of conveyor belt is often used in mining operations to transport materials to remote construction or building site locations, such as the bottom of a mining pit.
The belt is used for material transportation and is made of textile or rubber with a metallic or vulcanized joint. These belts are used for transporting solid and bulk materials at a great speed, covering great distances (up to 30 km).
3
CLASSIFICATION OF CONVEYOR BELTS a) According to Carcass 1. Textile belts i. Cotton fabric belts ii. Polyamide fabric belts iii. Polyester fabric belts iv. Aramid fabric belts v. Rip stop belts 2. Steel belts i. Steel rope belts ii. Steel cord fabric belts b) According to Cover 1. Abrasion resistant 2. Flame resistant c) According to Steep angle 1. Conveyor belt with no surface partitioning 2. Piece goods conveyor belts with cover patterning 3. Belts with chevron cleats 4. Box-section belts with corrugated sidewalls 5. Conveyor belts in sandwich design 6. Elevator belts
4
TAKE-UP DEVICES
INTRODUCTION Take-up bearings are a type of mounted bearing primarily used for adjusting and maintaining conveyor belt tension. Take-up is the process of adjusting the length of the belt and chain to compensate for stretch, shrinkage, or wear, and to maintain proper tension. This is done with the assembly of the necessary structural and mechanical parts, including take-up bearings. The take-up bearing assembly consists of a housed that is mounted to a frame. The bearing is guided along the frame by a slot in the bearing housing or other means. The take-up assembly contains a screw or other mechanism for adjusting its location along the frame. A shaft connects two take-up bearings, one mounted on each side of the assembly. When a conveyor belt or chain needs to be replaced or tightened, the take-up bearing is adjusted via the screw or other mechanism to provide the appropriate amount of tension on the system. All belt conveyors require the use of some form of take-up device for the following reasons: •
•
• •
To ensure adequate tension of the belt leaving the drive pulley so as to avoid any slippage of the belt To ensure proper belt tension at the loading and other points along the conveyor To compensate for changes in belt length due to elongation To provide extra length of belt when necessary for splicing purpose. 1
Usually there are two types of take up arrangements. •
•
Fixed take up device that may be adjusted periodically by manual operation Automatic take up devices for constant load type.
Screw take up system In a screw take up system the take up pulley rotates in two bearing blocks which may slide on stationery guide ways with the help of two screws. The tension is created by the two screws which are tightened and periodically adjusted with a spanner. It is preferable to use screws with trapezoidal thread t decrease the effort required to tighten the belt.
2
The main problem with the use of manual take-up is that it requires a vigilant and careful operator to observe when take up adjustment is required. Perfect tension adjustment with this system is also not possible. For this reason these devices are used only in case of short conveyors of up 60 m length and light duty.
Automatic take up arrangement
3
In automatic take up arrangement the take up pulley is mounted on slides or on a trolley which is pulled backwards by means of a steel rope and deflecting pulleys. The carriage travels on guide ways mounted parallel to the longitudinal axis of the conveyor, i.e., horizontally in horizontal conveyors and at an incline in inclined conveyors. Hydraulic, pneumatic and electrical take up devices are also used. Automatic take-up has the following features: • •
It is self adjusting and automatic Greater take-up movement is possible.
Endless conveyor belt after being threaded through the entire length of the conveyor need to be tightened so that sufficient frictional force is developed between the drive pulley and the belt, to make the belt move. Belts working under tension invariably gets elongated with time, which needs to be taken-up to maintain the desired tension in the 4
belt. A belt conveyor generally have a screw-type (mechanical) or a gravity-type counterweight take-up unit, also termed as belt tensioning device.
Gravity take up system In gravity take up , the tail and pulley is mounted on a movable carriage which is pulled backwards along the length of the conveyor by vertically hanging counter weight connected through a steel rope and deflecting pulleys. In an alternate design, the return side of the belt passes by the bottom of a counter-loaded deflector roll which is free to move down to keep the belt taught.
5
Take-up Bearing Component
•
•
•
Take-up bearings are used in conjunction with take-up frames. Take-up bearings and take-up frames can be sold as a unit (assembly) or as individual components. Take-up assembly (frame with bearings) - They often include a take-up assembly that consists of a guide frame, positioning screw, and hardware for position adjustment. Take-up bearing- Take-up bearings may be plain bearings, roller bearings, or ball bearings. Take-up frame- The frame is available in various sizes and housing styles.
Image Credit: Twentebelt
Bearing Specifications There are many specifications to consider when selecting a bearing for an application. Below is a condensed list of bearing specifications as they relate to take-up bearings.
Types of Bearings
•
There are three basic types of bearings used in take-up bearings: plain bearings, ball bearings, and roller bearings. Plain bearings provide continuous surface contact between inner and outer races, but do not include rolling elements. They are used to constrain, guide, or reduce friction in rotary or linear applications. 6
•
•
•
•
•
Ball bearings use balls between the inner and outer races to reduce friction. Roller bearings use rollers between the inner and outer races to reduce friction. They provide smooth, low friction motion in rotary applications. Bearing Dimensions Take-up bearings vary in terms of physical dimensions and operating specifications. Suppliers that use English design units measure bearings in inches (in) or fractions of an inch. Suppliers that use metric design units measure bearings in millimeters (mm) or centimeters (cm). Bore diameter is the most important physical dimension to consider. It is defined as the inner diameter of the bearing and fits the shaft of axle. Bearing width is proportional to the maximum load the bearing can support. When specifying a replacement bearing, it is important to select the appropriate width to ensure the bearing is compatible with the take-up frame. Operating Specifications In terms of operating specifications, the most important factors to consider are: Maximum speed- Maximum speed is the top rotational speed of the take-up bearing in revolutions per minute (rpm). Maximum speed is determined by the size of the bearing, lubrication, bearing material, cage material, and the desired lifespan of the bearing. In general, smaller bearings accelerate faster, but larger bearings hold speed better.
7
Selection Tip: Use a larger bearing for applications where continuous operation is necessary. Use a smaller bearing when the application requires direction changes or quick accelerations. •
Dynamic load- Dynamic load is measured in pounds (lbs) or Newtons (N) and represents the maximum rated radial load for a defined bearing life at the rated speed. Bearing Materials
Ball and roller take-up bearings are usually made from a carbon or stainless steel. Plain bearing take-ups are made from bronze or plastics such as polytetrafluoroethylene (PTFE), nylon, and Acetal polymers. Polytetrafluoroethylene (PTFE), a heat-tolerant polymer, is a fluorinated thermoplastic with outstanding chemical resistance, low leachability, and excellent lubricity. Teflon®, a registered trademark of DuPont Dow Elastomers, is a proprietary form of PTFE used with many take-up bearings. Nylon, a category that comprises several grades of polyamides, is commonly used as a bearing surface material because of its toughness, resistance, and pressure ratings. Semi-crystalline Acetal polymers offer excellent lubricity, fatigue resistance, and chemical resistance; however, they suffer from outgassing problems at elevated temperatures and become brittle at low temperatures. Bearing housings are usually manufactured from cast iron or steel, while take-up frames are typically made of steel or cast iron.
8
Bearing Features
•
•
•
•
•
•
Bearings can be designed with features that help improve their performance in an application. These features include: Self-lubricating- Ball and liner materials self-lubricate or do not require lubrication. Lubrication port- Bearing has an opening (port) for providing grease or oil relubrication. Corrosion resistant- Bearings are resistant to corrosion, rust, pitting, and discoloration. Self-aligning- Bearings can correct for a small amount of angular misalignment. Split bearing- The housing and/or bearing is split into two pieces and bolted together. Slot width- The slot that the take-up bearing rides on (if present), can either be narrow or wide. The take-up bearing slides along this slot in the frame to adjust the tension on the conveyor. It is important to ensure the take-up bearing fits and runs smoothly on the width of the slot in the frame.
Narrow Slot | Wide Slot Image Credit: APEX | Fastenal
Take-up Frame Specifications The frame is what holds the bearing and it comes with its own set of specifications to consider when selecting a take-up bearing.
9
Take-up Pull Configuration •
Center-pull products locate the adjustment pull axis through the center of the bearing.
Image Credit: CCIPulley •
Top-pull devices have the pull screw drive on the topside of the bearing.
Image Credit: Martin Sprocket •
Bottom-pull take-up bearings have the pull screw drives on the bottom of the bearing.
Image Credit: Take-up Frames Unlimited •
Tube take-up bearings have a screw encapsulated in a tube, with the bearing mounted to the end of the tube.
Image Credit: CCI
TAKE-UP FRAME SPECIFICATIONS •
Frame length- Frame length is determined by the length of the drum, or system which the frame will be attached
10
• •
•
to. The length must be long enough to ensure enough tension can be placed on the conveyor when tightened. Frame width- The width of the frame. Top angle- Top of the frame is shaped triangularly as shown in the picture below. Protected screw- Screw has a shield or cover for protection against debris, liquids, etc.
Image Credit: CCIPulley •
Take-up travel- The total adjustment range of bearing in frame. Take-up Bearings Applications
Take-up bearings are used in applications with conveyor belts such as, fans and blowers, food processing equipment, and agriculture equipment.
11
Metallic Conveyor Belts Conveyor Belts which can be used to convey different types of materials from one place to another though various industrial processes effectively.which are used in general material handling applications .conveyors are capable of conveying light, medium and heavy loads. Fabricated using spring steel, GI, SS and others ADVANTAGES •
Its positive drive gives constant belt speed
•
Tracking problems can be eliminated
•
Inclined conveying is possible with side guards & partitions
eg: quenching operation in the heat treatment process.
Because of its dense mesh construction and smooth surface this is most efficient for carrying small parts such as bearing parts, washers etc.
TYPES OF METAL BELT CONVEYORS •
Wire-Mesh Conveyors
Wiremesh chain conveyor is driven by twin strands of chains throughout the passage, therefore can well prevent the deflection/slanting of belt during circulation that may occur on traditional belts. Metal wiremesh conveyors feature flat carrying surface, ability to stand strong impact or pull and good ventilation of the carrying surface, allowing free flow of air or liquid for drying or washing-down purposes. Easy to maintain, detach, and re-assemble, widely used for deepfreeze food, roasting, drying and electronics industries. Heat-resistant wiremesh, ovenproof Wiremesh for ovens/furnaces, drying wiremesh conveyors, cooling wiremesh conveyors, washing-down wire-mesh belts, etc. applications for common procedures like drying, steaming, frying, & freezing in food processing and cooling, spraying, cleansing and heat treatment in metallurgy. 1
•
Hinged Steel Belt Conveyors
Hinged Steel Belt Conveyors are used to convey virtually any type of metal scrap. These rugged, heavy-duty conveyors are designed for long-term, low-maintenance operations in industrial, scrap, steel chip and fastener applications. They are ideally suited for carrying hot, oily parts from punch presses, forging machines, etc., to drums or hoppers. Various apron, side-wing, side-rail and frame designs are available
•
Steel Wire Conveyor Belts
Avail from us a huge spectrum of Steel Wire Conveyor Belt, which has been fabricated at our world facility using best grade material like high quality stainless steel, under the observation of our professional and skilled professional promising quality Belts. We are a client focused company and manufacture products as per clients' given specifications and avail them at market leading prices. These belts matches international quality standards and find application in Glass Industries, Auto Industries, Ceramic Industries, & Food Processing Industrie
2
LIMITATIONS
•
They are sensitive to hot materials and to materials that cause wear quickly
•
Can only be used in straight paths (changes in the line of motion are only
•
possible to a very limited extent)
•
Angles of inclination are limited
•
Dustproof designs require continuous maintenance or additional mechanical implements
•
They cannot be gas-tight
•
Only a single discharge point can be used for each belt conveyor
APPLICATIONS •
Automobile & Heat Treatment Application
Owing to the profound experience of the market, we have been able to offer belts for Automobile & 3
Heat Treatment Application. The products we offer are manufactured by a team of deft experts, following norms and guidelines laid down by the industry. All the offered products are exclusively developed for industrial purposes and are able to function at high temperature.
•
Glass & Ceramic Application
metallic belts that find their use in Glass & Ceramic Application. All our products are developed using qualitative raw material .To meet the diverse requirements of the clients, we offer products are in different sizes and specifications are available
•
Food Processing Application 4
We have in our store a wide and remarkable range of metallic belts that are used in Food Processing Applications. The belts we offer are maintaining the unchanging surface of the mesh belt by their deeply bent strings of strips that are properly positioned the spiral strips. Customers can avail these products from us in different sizes and specifications, as per their needs. Due to features like longer service life, resistance to corrosion & abrasion and seamless finishing, these products are widely appreciated by the patrons.
5
Luffing mechanism
Luffing mechanism is a crane mechanism where the hook remains at the same level whilst luffing; moving the jib up and down, so as to move the hook inwards and outwards relative to the base. Some types of crane are inherently level-luffing: those with a fixed horizontal jib, such as gantry, hammerhead or the fixed-jib tower cranes commonly used in construction. Usually though, the description is only applied to those with a luffing jib that have some additional mechanism applied to keep the hook level when luffing. Level-luffing is most important when careful movement of a load near ground level is required, such as in construction or shipbuilding. This partially explains the popularity of fixed horizontal jibs in these fields. Toplis cable luffing An early form of level-luffing gear was the "Toplis" design, invented by a Stothert & Pitt engineer in 1914.[2][3] The crane jibs luffs as for a conventional crane, with the end of the jib rising and falling. The crane's hook is kept level by automatically paying out enough extra cable to compensate for this. This is also a purely mechanical linkage, arranged by the reeving of the hoist cables to the jib over a number of pulleys at the crane's apex above the cab, so that luffing the jib upwards allows more free cable and lowers the hook to compensate. Horse-head jibs The usual mechanism for level-luffing in modern cranes is to add an additional "horse head" section to the top of the jib. By careful design of the geometry, this keeps level merely by the linked action of the pivots. Powered level-luffing As cranes and their control systems became more sophisticated, it became possible to control the level of luffing directly, by winching the hoist cable in and out as needed. The first of these systems used mechanical clutches between luffing and hoist drums, giving simplicity and a "near level" result.[5] Later systems have used modern electronic controls and quickly reversible motors with good slowspeed control to the hoist winch motors, so as to give a positioning accuracy of inches. Some early systems used controllable hydraulic gearboxes to achieve the same result, but these added complexity and cost and so were only popular where high accuracy was needed, such as for shipbuilding. Luffing cabs Luffing mechanisms have also been applied to the driver's cab being mounted on its own jib, following the movement of the crane's main jib These are used for tasks such as ship unloading, where the view from the driver's cab is greatly improved by cantilevering it forwards and over the ship.
1
2
APRON CONVEYORS An apron conveyor is a type of conveyor made from individual apron plates that are linked together with hinges on its underside, thus creating a looped carrying surface where materials can be placed. It plays a vital part in several industries by being used to move different materials from one location to another. This type of conveyor is used to deliver a large number of materials across several phases of production and is particularly useful for transport of huge and heavy materials.
Many industries consider apron conveyors to be a lifeline in their industry, including manufacturing, agricultural, and chemical industries. In the manufacturing industry, these conveyors are used to move materials across different sections during the manufacturing process; in the agricultural industry, they are used to deliver grains. Apron belts can be made to have walls that can ideal for moving materials with no containers, such as feed and gravel. In the chemical industry, apron belts are used to move hazardous materials that prevent workers from handling them.
1
An apron conveyor works much like the tracks of a battle tank. Individual apron plates overlap and are linked together to form a closed belt or chain. A mechanism, usually composed of several metal rollers, is placed inside the conveyor belt. Some rollers contain pins or teeth that hook into the holes or grooves built under the apron plates. When the rollers turn, the teeth that are hooked to the plates move, which then moves the apron conveyor belt along the rollers. This action is similar to when a sprocket moves a bicycle chain when the pedals are pushed. The operator can adjust the speed and direction of the conveyor through the mechanism. Since the apron conveyor belt forms a loop, it can work continuously as long as the roller mechanism turns.
2
3
There are several advantages of using apron conveyors. This conveyor can be adjusted to any length by changing the number of plates. Maintenance and repair are also easier. When a part of the conveyor breaks, the damaged plates can be removed and replaced instead of the whole conveyor, which saves the operator time and cost. Apron conveyors made from high grade steel are useful for handling abrasive materials, such as rocks and granules. Walls and overlap in the apron plates ensure minimal material loss, especially when transporting grains and detritus. Mainly used for industrial purposes, these conveyors are made to withstand tremendous weight, heat, and continuous operation. The conveyor can be treated with special coatings to achieve a desired surface, such as friction or elasticity. Apron conveyors, however, are not recommended for use in the food industry since there is risk of contamination from the conveyor surface.
4
012234536894 3 962
! " # !$ % &! ' $ "% %( )' '
(* & "+,-&! ' .& !- ' & ! &*/ 0& % - !*% & ) 0/ ) " - % & - 1 + 2 *& *& -) & !%& '' %)- ! ) *&( % +3 % '*" *&&% /- %% "/ % / $ / ! /- / / & * &%*( (* & "+ 2 -! -% $ ! "* ( '% %/& -$(%& - %-$ % "- +,-$-! ) " !45% &* "! $-!$ '' 6/ -$(*& "* &% % ) & 5 % 5- ( /& -$$( ) - % '&' * & *+ .'* " '* / )- $ - !$( *)- -$( 0& )+
78 9:;<=>?;8; <=;@=?89; AB361CD9414EF1 9GC
<=9H8=>I9;:=JHJK <=8=L8;=?J88@=MK=; ;N ?88@=8;9;:=O8;=> PQRSTSRUVW =;@=>I8==??[9>8K=\]^=L88=_`ab]`ac=>d=?8= 8;@a=ef8=K?9=;:8=L=9;9;9;=L=;= 8 ==f8=f9g;=L=8I8=9 =b`=@8:88 =J9f== ;@@=9 8PQhTiRjRQTSRUVWVXXYXYZ=O?==MO=c`=L88= _\k=>da=l@8;=8 =fI8= 9;:8N?988=O>9;O>== 9;8
= 88= 8? =f=>I8=;== K 8>=L= H =9;==;9;OO =?a =fI8=f88=K?9=;L9:O9;=?9; m=nTiThhXh=_O?=;@=@J;=8 = 9@8=MK= 9@8==
8?8@=MK==@9 ;8<= 88;=L8;=9;=>8= 9; =;@=>O98I8=>9;=?9O8= f88 d<=QiRooQiUoo=_>9;9>9g8 = ?8=8pO98>8; =MK=q H9;:q=8 =f=:=9;=;8=@989;<= L8pO8;K=O 8@=9;=@8?>8;= 8 == f??9;:=8;8 d<=;@=rshSRnhXWnTiThhXh=_J==>8=8 = :8f8=f=I8=9;=;8=@989;=;8[==;8==J=8 =9;=f8= >8=M;H=f=I8=9;=f8=f8= @989;daP\Z =8=8pO98@==fI8=>I9;:=f;@9 =f=H88?=?8=J9f=f8=>I8>8;=L=f8= 8? a=ef9 = f8? =9@8 = 8@K=f8> 8I8 <=8 ?89K=Jf8;= 8??9;:=;=f8=>I9;:= 9 a=t 9;K<==f;@9= J9=>I8=== 9:fK=@9LL88;= ?88@=L>=f8= 8? <=O 9;:=9==q88?q= JK=LJ@==MHJ@= 89I8==f8= 8? a=u9@8 =>K=L9;@=f9 =8LL8=@9 ;89;:=;@=f9 =?M8>= fO@=M8=L9[8@a ef8=@989;=L=8 =>I8>8;=_O?==@J;d=;=M8=?8>;8;K= 8<==M8=;8@=MK=?8 ;;8= @9;:==f8=?8@>9;;=LJ=L=f8=J@<==M8=;8@=O>9Ka=v;= >8= 8O? <=@989;= VXXYXYZ
01345674889 64 603 884997 7709107169697 6694664 47 66964691169 01 747
9 146 669 0793604501546799719 089 119597014569913 8 647
! "#$%& '$ !(& $
)*+,-./0*12*2345106*322/45*/64373510*8/69:+;*9+47,89+:*<=>69437*0/?,90/-/+56;*7143591+;*5032294*<355/0+6;* 632/5>*41+698/03591+6;*3+8*3/65=/594*<0/2/0/+4/6@*A10/-165;*<=>69437*2345106*79B/*5=/*C/059437*3+8* =109D1+537*89653+4/*51*./*6<3++/8*-,65*./*41+698/0/8@*E=/6/*2345106*F977*8/5/0-9+/*5=/*7/+:5=*3+8*<954=* 12*5=/*/64373510@*E=/*.,9789+:*9+203650,45,0/*-,65*./*3.7/*51*6,<<105*5=/*=/3C>*41-<1+/+56@*E=/* /64373510*6=1,78*./*71435/8*F=/0/*95*43+*./*/3697>*6//+*.>*5=/*:/+/037*<,.794@*G+*8/<305-/+5*6510/6;* 4,651-/06*6=1,78*./*3.7/*51*C9/F*5=/*-/04=3+896/*/3697>@*A,05=/0-10/;*,<*3+8*81F+*/64373510*5032294* 6=1,78*./*<=>694377>*6/<3035/8*3+8*6=1,78*+15*7/38*9+51*41+29+/8*6<34/6@ E032294*<355/0+6*-,65*3761*./*3+5949<35/8@*G+*61-/*.,9789+:6;*5=/*1.H/459C/*96*69-<7>*51*-1C/**./*3*-10/*6*5=/*0/?,90/8*+,-./0*12* <366/+:/06@*A10*/I3-<7/;*3*69+:7/JF985=*/64373510*503C/79+:*35*3.1,5*K@L*2//5*MN@L*-O*9+:*43<3495>*12*3+*/64373510*6>65/-*-,65*-354=*5=/* /I*89641,03:/6*-165**0/8,4/* 6/4,095>*41+4/0+6@*S9-97307>;*/643735106*125/+*30/*,6/8*36*5=/*/I95*201-*390<105*6/4,095>*4=/4B<19+56@*S,4=* 3+*/:0/66*<19+5*F1,78*65977*:/+/0377>*./*65322/8*51*<0/C/+5*956*,6/*36*3+*/+503+4/*8,09+:*59-/6*12*79:=5* *-/3+6*12* 503+6<105*./5F//+*271106@Q4953591+*+//8/8R*G5*-3>*3761*./*+/4/6630>*51*<01C98/*3+*/7/C3510*7925*+/30*5=/* /64373510*210*F=//74=3906*3+8*8963.7/8*;*41+698/03591+*6=1,78*./*:9C/+*51*5=/*3/65=/5946*12* 5=/*/64373510@
TUVWUXYXZ[
\]X^_X`aWb]ZcUdV[ e919648 647 14 19693 79 1936045146967 3f1 1988 1699 71 5 46471 6 6 7096916 071ge9648 647 3456 05169 4647 119 8 5 69 05 7099 7089 694664 48 169169796 750 8971743f961ge91919360451 814 53476995 1469 913 8 64767 11gh5
06045698 647 13456 05 84478 69 5 34 8 69ge984478 69 740 91 8 394769 11959716416 5 947969169456469 40516 071ge018 6901 8 1066905019 8447 5 0190697059 4779 4 8964 8849 1 339116469
012345678 6 36 2 0 16 4 36 4626 6 665 36 14 5178 7 16 15 36 0 45 6 4 5106 6216 4 66 31 1 6746 2 61 31 7660 6 36 663 1 2 0 366 663 063 43 012345 2 61 5 36 66 36 6 34 645 4 5626178 0454046 36 1 6 665 36 147 15 36 1545 3423 36 7665 62 7 0 645 213 45 36 1 36 7 4 1 3 061 7276 31 746 36 67 15 67 1545 4 2 0 6 46 624 5 456 6367 43 27 7126 127 36 0 15 6 36 36 65 36 7 176 11236 36 15 0 1545 1 70 41 66 7 2 52766 7 36 7 217746 1 36 7143 712 624 5 2 556245 36 67 15 67 624 5 !"# 36 712 860 4 4 45 36 7 46 36 6 23145 3423 2 545 8 36 6 7 0 36 0 1 70 15 12 36 45 15 65 6 3676 176 121 8 712$ 56 7 36 7 5 366 36 6 %21 6 36 6& 366 712' 15 56 7 36 12 366 36 6 %21 6 36 714 67& 366 712' 36 76 146 44 5 366 712 216 36 6 70 1 147216 1 368 0 6 7 0 567 36 2 0 16 ( 5 36 7143 624 5 36 7 36 712 176 1 3647 01)400 41526 117 34 2 54714 5 726 36 12 56 6 6 1 1 *+&6766 15 6 76 146 36 6 6345 4 34 743 15 6 65 36 6 45 1 316 7660 45 1 147216 ( 36 15 0 36 621 1 7 36 712 2 5676 31 36 7 5 15 12 366 36 6 176 1 0 45 1 7143 456 34 216 36 147 18 45 1 1 366 46 177156065 56 167 15 367 368 215 614 8 716 17 5 36 65 45 36 276 624 5 712 36 712 21778 36 6 5 1 5 36 56746 36 7 54 368 76123 36 0 1545 3676 368 1 37 3 15 367 276 624 5 712
6 76 6)445 36 0 1545 ( 34 45 36 712 61716 15 36 6 526 1145 106 1 147216 2 54714 5 34 282 6 4 76616 2 5451 8 1 36 6 176 6 7 0
0 15 12 36 0 1145 ,-./ 36 6 3606 6 176 4 56 4626 46&21 1 0450 7 66 06 6017214 5 456 018 6 16 2 617 8 454216 3647 66 5 0 621 1 7 0 6 0151276 167 1*2+
3 36 7467 15 36 761 6123 6 4 2 616 %465 1 74
6 16171526' 43 2 0 46 7 74 5 31 063 43 36 2 0 16 5 36 15 0 1 70 15 36 226645 6 45 36 23145 366 6767& 7 46&864 621 1 7 %66 6 ' 6176 1 761 15 0 3 74675 367 621 1 7 0 6 316 2 616 761 15 0 3 7467 36 6 176 456 8 1 2 545 061 23145 31 70 1 2 6 36 7 5 15 12 66 36 6 176 6123 2 55626 366 36 7617 366 176 6 7367 117 4 45 36 12
01234267089 1 60 899 8298 10912 90 060 0896211 91 1 6001234793197 2 9089 0 6 089012343 601 089 196020 6 08909 89826712 1 7923 69696082678 7 1296 91 8 9089219176 089932 20 1 !626932 20 1089826712 "
972 6 0012342382608203 66930970 089#26719 9212919 "
9!03 601"3097 "170630930 60089396091 089826712 2$ 791$2 46 622$ 791 $ 8382 291 23 00 6 1608903090 9 89 "1 9 089 791 2910 2
089826712 0 # 9# 08 2 6 001234 89690
29146 62089$096 6#9#91$3 60 90891099 32 9 1
20099 029267 1 79089826712 08096 90196 08267
9 0%60 096 6#9#912190896691 3 601"30 63 # 6960 838219#279 389#32
01920971"9179 6970 19960089
291 1 #921206 &62
089 "091 291'089 6 2100820296 91230"2
99'089 3 91 8382 967 608903 #912671"91 83 9179 6970 190 79 12720 6 1 #961 6#9602 3 670 6#9382632 92126709212678"#262672 # !6089 230 1826712 2193 601"3097 9976 1"91081 " 823 #"091(3 601
97 901" 6#238690 1 7"39 291 08919)"197*9267096 17910 #203893 3 1791 893 # 6960 291 2131"91267099 21982974
97 14919 19 96 9760 089199 8919089219 "970 90891 !6089#7(0 9609083960"1 #9826712 79 63 6097 21"919
0816 # 08#902 3 2776 32
97$1239 90$ 239790 99692383 8 29089826712 21 7 90
9 9 99 770 62
92389
930 6 26 # 1908262 9 990 6 210 089826712 272#2 97 6 089279 #9606997970 919 2397 899 1# 826712 829 21 9 99619 2397 083 6960 62 213(267(1"9112 6
012234536894 3 9623 0 9 451461 2
012341578984 4 242
!"#$%&'"()$*&+"(",&-"&!.(/(%$0"%12&!"-&0&"3#!%(//&'"3#"4(5$0"'&2(0%4&#%"!%$0&!"63#./7'3#8"9(00$'!:" )&,$0&"%;&"<=2$>" ?1"@ABA+"%;&",30!%"$,"C&#$D!"E3#./3#&'"&/&*(%$0!E"-&0&"3#.$02$0(%&'"3#%$"%;&"?/$$43#8'(/&"?0$!>"!%$0&"(%" F;30'"*&"(#'"GB%;"H%0&&%>"F;3!"-(!"%;&",30!%"0&%(3/"(22/3.(%3$#"$,"%;&"'&*3.&!"3#"%;&"IH+"(#'"#$"!4(//" .$3#.3'&#.&+".$#!3'&03#8"%;(%"C&#$J!"2034(01",3#(#.3&0"-(!"K14(#"?/$$43#8'(/&+".$L$-#&0"$,"%;&" '&2(0%4&#%"!%$0&"-3%;")0$%;&0"M$!&2;"?/$$43#8'(/&>NOPQ
RSTU V
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
`a914 242 8
bV c cS UcSV d
e#"@B\G+"%;&"4&03.(#"Y$$/&#"W$42(#1D!"Y$$'"f3//"3#"K(-0&#.&+"f(!!(.;7!&%%!"6%;&#"E%;&"/(08&!%" !3#8/&"-$0!%&'"43//"3#"%;&"-$0/'E:"7%3/3[&'"g%3!J"H&&)&08&0L%12&"E0&*&0!3)/&E"&!.(/(%$0!"%$".(001"3%!"-$0_&0!" )&%-&&#",/$$0!",$70"%34&!"("'(1>NOhQ"F;&"4(.;3#&!"'3'"#$%"07#"(//"'(1i"0(%;&0+"&!.(/(%$0!"0(#"!$/&/1"%$" %0(#!2$0%"&42/$1&&!"%$j,0$4"43''(1"4&(/!"(#'"3#j$7%"$,"%;&"43//>"e#"3%!"('*&0%3!3#8+"g%3!"ENOGQ
l U mS
e#"H(#"n0(#.3!.$+"(#"&!.(/(%$0"(%"97#%&0!"o$3#%"X(*(/"H;321(0'"-(!"7!&'"%$".$#*&1"2&0!$##&/")&%-&&#" %;&",30!%"(#'"%;30'",/$$0!>"%"%;&"%34&"$,"3%!".$#!%07.%3$#"3#"@BhA+"3%"-(!"%$7%&'"%;7!i"EN3%";(!"%;&Q";38;&!%" /3,%"$,"(#1"3#'7!%03(/")73/'3#8"3#"%;&"-$0/'>"e%"03!&!"hP",&&%"6@P>A"4&%&0!:>ENO]Q NOqQ
0 1 34 5 6 7 8 9
9
! "#$%& "! " & &
& & '() *&&$"+&&$ &$&$ (&&#,&& -$ " &"&& .& . . "+& . "&& ( & /,0-1 ) ( ) & &" /2" *& & . $ * " &/
3456875
1 )(& *&) & 6 7899:;<;=>:?&(( **& &.& @& &" &*A ** & && & &" &(&/1 &" & (* $&"(" " ()) (* * B&&&/ CDEFGH
01232567819 1 53 711 789721 783 231 627822377 881 75 1 587 2 23 1 3 88 21231871 78218 72 256781 8 828191 7 6 77 7 82 6728 67 7 8 1 87 2387277 8278! 7277 "# 378$%%
! &' 378(#%%
! 23867719(%%977267
27& 727867871 !61775 ) 2 1 121
*+,-./011234567458/
9 237(:;%8< 167 7167237=677585827 928 92 7 2 1 5> 7011 ?66 71923702277@7 1 9 82 227 >7 7 = 2A7 !612125678 2 7 1 82272237022779 82 227 >7 7 23775(:;%88 72278275B7 3 867 != 88277 8 1 61 7 2 27C D1 7E77 7 F217(:;GH3772 2719237=677581 6721237237 7 82 85827 88232237 7 I 87 A1 78123 7 81 1 621G6887 7817 8 2 71851 917 7196887 78621(%%%%6731!3778237 2 86122 1 A1 78 17 982 1 H377 2 72123785827 8 7 75 77821 231 7227627819 671 83679278312 82 7237276278777727211 78 78 682 1 7 12372191 61788 75 21 1729827 1 23 32 772 182 32 7212377 25872 1 H376887 787727231361 62321 78 867719(& I3: 63!H377 67 7 78 9 216887 7831 77721 782 31218723785827 2177211818975<7 716 1 3 91237 85827 6787 2737 78181 752370227727 H37=67758 27 721787 882 1 785827 1 78312 82 7812191 772 1 7772 1 2861 7 25 7 2 7 891671 7 2 1 2982
!=2 753 31 77 1 7 82 78H3785827 882 7 716 7 2 (:;&2 7 77 2 211
7 612 1 1237227 622 77275 237(:$%88237HJKH1221 J1 2LLL!3 3 87 71675<882 JH 3187612125678 827 237 89 78 721 822 1 H37867727 25 7 28" I3# 63!3 7237 86778(& I3:
63!928273 9 7721 281 67 25 8 7 71
7 57 61 27 9 237 (::%8237M175@1 N51 6 5627 27 7 778 21 7 197 1 5 9278H 85827 877 8272B 78=2772=22 1 @71 7 0 8 7 61282 H3787 72 23618 2 77861 8791 2376 2 1 67 7 2 822 1 877 7H3 885827 819237722567 2387O7 719728 1 2 9977 286778217727 77727 7887O7 719 9977 286773 8 881 87
01234563789 63843 7 5233 657 9 9 7 83 945 84 497 3 7 !! 97 31234563789 5233 9 9 9 5789
3 57 83 78294793"#53737$3 84 89857 57 945% &8 '548 58 234983 98 6( )* 62+ ,-8 -3 8 232 3 57 8354 ,9 97 3 83 233 9 43- 3 8 . 6( )/ 62+% 8 9 ,337 3856983 898 66-834 -57 9 9 9 - 9 85 85 3 9 9 - 93 657-83 234 33 97 ! -4 9 394%0 589857 73331 257 83 5233 9 9 5 53 -57 97 834 657 9 9 31 328 898 '4 9'38 8343 943 23 59 24 3-43 8 '
37 35757 4 3957% 437 85 9 9 9 5784- 3 89'' )337 343 57 3
39 38+ 38346573 - 97 - 78 -3 58% & 4534 6-8 93 98 398 73 97 '433 8 83 97495 83 94457 ,9 2257 38 % 4 943 57'546 6-8 -3 83 45794 9 9 7394,% 57 3783457 8343 5 9 !63843 9 3 349857 673 343 83 74-77 5 9 3453 ' 6389 4
34% 8534 897 85
58 ,8 '338 7 833 4
34 97 -3 73 97 8 83 97495 97 38 58 2-
836 898 83 53 34 83 4
34% 93 539 5 8 9 3 34983 83 4534 898 83 5
,3 8493 57 '98 37- 8 832 78 83 657 9 9 ,3 8% 8534 84 8 9 7 833 4
34 943 98 575'5 978 45 ' '9
57 34% 57 3 7 83 9 9 4534 97 897 4 9 % 557 8 :3877 9 ' 6857 8343 5 7 23 59 379857 ' 8493
57 98 233 31 328 '4 3957% &8 83 3158 83 963 83 75;-3 5 -3 8 3 3 34983 83 4534% 234 832 7 8 9 3453 ' 4
34 5 3 3 34983 836 49834 897 83 9,4-28 9 8 5 - 83453 893 2 9 3% 7 !!* 9 565 94 5233 9 9 9 2373 57 83 73 2373 534 ' 3947 7834798579 &54248 57 9478 <9799% 95 9 9 5 ' 83 29
38 823 49834 897 83 ,3 8 823% 93 29
38 =5783463= 58 9 6, 97 8 9449736378% 93 31297 -8 ' 39 834 37 23357 -2 97 6243 578 39 834 37 57 7% 93 97495 57 4 57 9 565 94 697734% 93 9 9 63 98 4- 6( 37 4534 832 78 58 233 -2 8 9224156983 * 6( '4 83 ,- ' 83
378 97 8 6( 9957 98 83 37% 7 9 !!. 58 9 977-7 3 898 ,3 9-3 ' 58 -743 59,5 58 97 83 7-6,34 ' -34 957 9 5378 57 ! 83 945597 5233 657 9 9 5
,3 432 9 3 58 9 89794 657 9 9%
0123415689 41 3
!"! #$#%! !"$# # %!%$$% %&#'# %& %&' %#( )%& %$$ % %&#!"% !%##!&$$ #%)#* * ## + %& $ %' ! %#, -& #%!& %&# *# %& %! "% % $$ &%& #%& !# !)!%# %!%& &!%!% &#%%&'#)#!$ ! &!%& %!"#%& #% %&%& #!'%&# $)!%& % &%!%# !%&##! %!$ , .$ #%%!%#!!% "!!&$$ #%#!%%# !$#%$ !! #! %&# #%! *% !%#!!"% "!,
011234563789
!"#$%#&'
(( ) *)+ + ) , - (, ), ( ) , ( * ) ) -.) / 0 1 2 ) 3 *4 * ( ) ,56'76897:;"<"&'
(, ((= , ) ) ( ( ,) > ?@ABCAD2( 4 (> E ( * (= ( F (, ) ) = , ( ( )) -G H > I 0 2 J *K/( ( > > L L *MN*( ) , / OP%%' Q ( ((* (F )= , ( ( ) , -2 ( 2( ( ( )
0134567899 0 548995385 8957068 57 5670 35 0 558 75000 35307 8430594 5338365 3554 853 !"# 058 355 48 $ 753%3 68360 7 0 3&070 8 $ 75397$573 5 '3(8 5)8 370 % 8$5 3501807 375*89$08337348335 5 37 08 7 8 7358 $7 7538 8 8670 3 055+849537 69 5, 5-9 8*735 %8 0995 60835 85 0*69035.3 0*0 97 (0 30 %5+83/08807 *89$*8 *7 08 87910 48335 5 303540 4 70 008 7 57 68 5*89$*8 *0 905 853853455835844 0867 68 3%8990*7 48335 5 3604957 5 7503540118 10 08 7 48335 5 305 5 568 .90 3458$5 8
0 651)07 60 5 0 %495835*86 0 35410*8 01507 *89$*8 255+71 054865)0 87 8 8670 838973 5 30 9 83890 07 *89$*8 *7668 537 697 870 9749575355+71 0547 853015 58 758 8 8670 838973 5 30 9838 7 697 507 *89$*8 9587 0*8 3871304 55+71 05(8 5)8 370 8 8670 838973 5 30 98383 8707 *89$*8 *76 958305 75'35+7
67 8 9 9 : ; < = > ? @ A = > 8 ; B C D 8 @ .30447 68 60 5 0 7385765 357 97&9559 587930 5310 07 30447 68 348 89959
8 8E865 08 5368980 0445 368 90857 30447 68 30 0560 5 0 %3540 05 5368980 % 7555368980 *7568 537558 609956568 *7560 87 5 5 68 73585 5+9559FGH 37957 697 507 *89$*8 368 5 357 97&9559 587930 530 8 340 30447 68 3 5*55 1900 3%5 8 583306785*73815 8I8 3/3 683%*78 3 0995 32FGH8 8$5 4 80 *76583 61900 348658383548 8568 60 5 0 3 35%568 3507 *89$*8 368 0 57 3899587 697 870 3 585 8 GJ5 553%*795868 60 5 0 68 045 8588 7 697 870 01 40KL5 553FJHFKHM 9 34567899 &537 530447 68 368 5 8 340 5*7868 60 5 0
N@:;>:9OC=8P=89C@?A:8;
35 5 35 *73530045 8555765%5 4 3530447 68 0 55765'33815 00 3Q 7537 51900 5 7 56530447 68 '3*55937 054 045 403770 55765 5 35 35354 535 6501568 8 4 9937 405 5+30 59559FGH576535 5 899 158 5 30530 0183 35%3 6830 5&*8 7 53FGH0 835 30 %FRH03044504951 05 5 7 5 5765 530447 68 60 5 0 045 8538 0 585 34558 738E865 5368980 10 45049573 8990*36 305 375090857 68 30 055765% 7555368980 8 5 755568 85
5+9559FGHFRH
012425672789 9 2 2824617 86 21 697818185227189678 282 8 12 26922469 894 524 127 952 691289 121 69782869 252 1227189462 8 69 1278
!"#!$%!&!' ()$
*82922 258 6426924 522 2 22298 6 469+
,82922 258 78876 62 824 128586 8 2
872-2928 82922 258 82 8586 8 2697887662 ./// 0/// 9412//345//67692//8 9414 /67697229 7686 9922424-2928 82922 258 69 6 469 261
22821 48 67 2 276716717892871224 4//2226921.971 48 67894 2//222 6921.2496972 2767:9 6 469 29
2 276789428 22 258 82 662 1852224 2//2226921 978948 5229
2248922// 4///222 6921 3./977686 9922424 ; 26282922 258 82248876 89 8 961967 8< 2=8 212268 886 9942 94 672 258 69>8 8?6869216718628292 12 816 8 5212@ 876;28 916711 2 8227124 8992 7824 912 2871 2 *A87 B62C 86 96912@6 8 D2 122 258 18 56428772 1286 9 816 9261 1
4 4 2876 89 86 9E1286 9+6762 862822697188 188292789 8 2871122 258 122989726912 276 5672528;228 12F 258 8989 276 9 GHIJKLMNLIOKKJPQJRLJSJTOUMRK VWXXYZ[Y\]Y^Y_W`a\X]bWc]dY]XeYfgW^ghYi]ja\]`kY]XY\_gfY]`kYc]eY\ja\bl]gZf^migZ[n]kaXeg`W^]YbY\[YZfc] opaiY]d^mYql]j\aZ`]WZi]\YW\]YZ`\WZfYXl]W]`Y^Y_gXgaZ]gZ]kg[kr\gXY]dmg^igZ[Xl]iamd^Y]iYfsY\l]WZi]a`kY\]mXYXt] pW\X]bWc]dY]a\ZW`Y]gZ]`kYg\]gZ`Y\ga\]WeeYW\WZfYl]bWc]kW_Y]Wmiga]_gXmW^]Wi_Y\`gXgZ[l]WZi]bWc]dY]e\a_giYi] ug`k]XeYfgW^ghYi]\Yfa\iYi]_agfY]WZZamZfYbYZ`Xt]v^Y_W`a\X]bWc]W^Xa]kW_Y]^amiXeYWsY\X]gZ]`kYb]`a]e^Wc] fW^bl]YWXc]^gX`YZgZ[]bmXgft]wmfk]bmXgf]gX]aj`YZ]\YjY\\Yi]`a]WX]Y^Y_W`a\]bmXgft xZ]Yye\YXX]Y^Y_W`a\]iaYX]Za`]XY\_Y]W^^]j^aa\Xt]za\]YyWbe^Yl]g`]ba_YX]dY`uYYZ]`kY][\amZi]j^aa\]WZi]W] Xsc^addcl]a\]g`]ba_YX]j\ab]`kY][\amZi]j^aa\]a\]W]Xsc^addc]`a]W]\WZ[Y]aj]j^aa\Xl]XsgeegZ[]j^aa\X]gZ]dY`uYYZt] {kYXY]W\Y]YXeYfgW^^c]eaem^W\]gZ]YWX`Y\Z]xXgWt|
}OIO~UH 2642968 2 258 8 28 29 1 9 877 482 922 916 2 282 82 29 1 218984 29122 7186 8 2 258 82768 624 2 2 258 426924 528122 7186.4221 57 2789 29877 482C 922 9698122 71868 862618 84 52/ 941 /67
0123456468913 4933 39264 13451591519643029952 951439326 846
0123456468913 4933 39264 13451591519643029952 9 51439326 846
07-May-14
Flight Conveyors
• Inside the equipment, a set of chains is attached to paddles or similar tools. When the flight conveyor is turned on, the chains are pulled through the sealed trough, dragging the paddles along with them. This forces the material inside to move and scrapes down the sides in the process to limit material buildup. Technicians can adjust the speed for different materials, changing the rate of movement for the chains to accommodate sluggish or free-flowing contents.
• A flight conveyor pushes materials through a sealed trough. This equipment is used specifically with loose materials that may be wet, sticky, or clumpy, such as grain, unprocessed rock, or silage. Flight conveyors can be configured into a production line in a variety of ways. It may be possible to convert existing conveyor systems to this technology if necessary, especially if they already have a trough design with a similar footprint. 1
2
• The sealed trough offers a number of advantages. If companies handle dusty or highly loose materials, a flight conveyor can minimize the release of particles into the air. This can keep working environments cleaner in addition to reducing health problems caused by inhaling dust and chaff. Equipment should run more smoothly when it’s not fouled with debris from the conveyor belt, and the sealed nature also prevents contamination of
3
4
• These conveyor systems can be used to move materials vertically as well as horizontally. They may have multiple outlets to dump into processing troughs, which can be useful for mass production. Some are on adjustable arms to allow technicians to move the conveyor line. Rubber seals can allow a sealed connection to storage bins and vats, minimizing loose material in the environment. The flight conveyor is also easy to clean by flushing with hot water and solvents and running the chains to circulate the fluid. 5
6
1
07-May-14
Bucket Flight Conveyors
7
• A bucket conveyor is a mechanical devices used to transport products from one stage to another. Bucket conveyors traditionally are found in factory settings and can be used for tasks ranging from moving small candies off a production line to transporting plastic parts along an assembly line to moving hazardous chemicals safely and more. These tools also are used in non-factory industries. No matter how they are used, bucket conveyors provide a sanitary, gentle, safe, and often quiet way of transporting physical goods.
8
• A bucket conveyor is a series of attached buckets, or open-ended containers, linked by a drive train. As a motor turns this drive train, the buckets move in a continuous loop, like a conveyor belt. Construction of conveyor buckets is flexible, allowing for horizontal, vertical and angled movement of the products. Bucket conveyor systems can be customized to travel for as long a distance as is necessary for the job.
9
• In a factory setting, a bucket conveyor helps products travel from one stage of assembly to the next. For example, if a company is using a bucket conveyor for producing and packaging hard candies, the conveyor would be placed at the end of the assembly line. Candies would roll off the line and directly into the buckets. Then they would be ferried away and dumped when the buckets overturn at the end of the loop before heading back to the starting place. The candies are dumped into the packaging area, thus saving the need for workers to carry those candies from one area to the other.
10
• In a non-factory setting, bucket conveyors are designed for more heavy duty use. With mining and drilling, for example, the end of a bucket conveyor is placed where the digging happens. In order to avoid filling a mine with unwanted rock and soil, this debris is loaded onto the buckets. It is then taken to the surface and discarded properly. This system's continuous motion avoids the works stoppage required to remove debris manually.
11
12
2
07-May-14
• Most bucket conveyor systems are fully customizable to meet usage demands. Many bucket systems that deal with dusty products, such as sugar or flour, are enclosed to avoid spreading the product. Motor speeds can be adjusted also, to meet the demand of the production line. Buckets come in a variety of metal, plastic and synthetic materials, all designed to meet the needs of the specific production line on which they are used.
13
3
LIFTS For vertical movement of materials and men between different floors of a multistoried factory or building, freight elevators or lifts are used. Such a freight elevator/lift consists of a box type cage or car, which moves vertically up and down through the designed opening kept in the floors, called shaft of the elevator. The movement of the car is guided by guide rails laid vertically in the shaft. The car is suspended from and moved up and down by a hoisting mechanism, located at the top of the shaft. The hoisting mechanism may either be (i) drum winch type or (ii) traction-type, as shown in Fig. 8.4.9. In the drum-type, one end of wire rope is firmly attached to the drum, and the other end to the elevator car top. A counterweight, usually equal to the weight of empty car plus one third of the duty load, is used for increasing the load lifting capacity of the winch motor of given rating. However, winch type mechanism is 1
bulky and may pose difficulty in accommodating the winch at shaft top. In such cases, the traction-type mechanism consisting of multiple rope and multiple groove sheave, driven by a motor through gear box is used. Beneath both the car and counterweight, spring type buffers are provided for shock absorption. Proper drive controls and indication instruments for knowing position of the car are provided. Freight elevator/ lift is provided with automatic brake which operates if the rope snaps and the car develops high acceleration. The speed of freight elevators are kept low, while the passenger lifts in high rises are quite fast (500 mpm or higher). Cars of a freight elevator may be designed to suit type of materials they have to carry and for automatic loading by devices like: (i) fork lift truck or platform truck (ii) tow truck or trailers (iii) roller conveyor (iv) overhead monorail conveyor etc.
Fig. 8.4.10 shows a schematic view of an elevator showing the car supported in guide, the tractiontype hoisting mechanism, counterweight and buffer springs.
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
CRADLE CONVEYOR
The Rollers, frames, and belts of a conveyor system used to transport heavy materials in the mining industry are often damaged, especially components located beneath the conveyor’s area where loads are dumped. To boost performance and life in those components, engineers at Martin Engineering, Neponset, Ill. (www.martin-eng.com), designed the EVO line of conveyor components. The impact cradle, for example, fits beneath the conveyor belt while it travels through the loading zone. The cradle uses patented idler rollers linked together by connector brackets. This lets the rollers work together as a stronger, unified structure. Elastomer suspension bars absorb shocks and maximize the life of the conveyor belt and rolling components. The bars have a low-friction upper layer of UHMW and an energy-absorbing lower layer of rubber. The cradle lets the belt travel faster and carry greater loads through the loading zone. Rollers are mounted closer to each other for better belt support. The unit is comprised of modular components, each small and light enough to be manually removed, eliminating the need for cranes and other equipment for most maintenance and troubleshooting. To decrease spillage and ensure the cradle matches the idler profiles, the wings can be adjusted and fine-tuned. This also lets the cradle accommodate belt widths and side angles that correspond to CEMA, DIN, SABS, and other standard conveyor sizes.
A cradle conveyor is a convenient way for conveying bulk material from one location to another, and also multi-axially.Cradle conveyors are used for transporting, feeding,dosing,distributing and discharging bulk materials. Cradle conveyors are durable and reliable components used in automated distribution and warehousing. In combination with computer controlled pallet handling equipment this allows for more efficient retail, wholesale, and manufacturing distribution. It is considered a labor saving system that allows large volumes to move rapidly through a process, allowing companies to ship or receive higher volumes with smaller storage space and with less labor expense. Rubber conveyor belts are commonly used to convey items with irregular bottom surfaces, small items that would fall in between rollers (e.g. a sushi conveyor bar), or bags of product that would sag between rollers. Belt conveyors are generally fairly similar in construction consisting of a metal frame with rollers at either end of a flat metal bed. The belt is looped around each of the rollers and when one of the rollers is powered (by an electrical motor) the belting slides across the solid metal frame bed, moving the product. In heavy use applications the beds which the belting is pulled over are replaced with rollers. The rollers allow weight to be conveyed as they reduce the amount of friction generated from the heavier loading on the belting. Belt conveyors can now be manufactured with curved sections which use tapered rollers and curved belting to convey products around a corner. These conveyor systems are commonly used in postal sorting offices and airport baggage handling
1
systems. A sandwich belt conveyor uses two conveyor belts, face-to-face, to firmly contain the item being carried, making steep incline and even vertical-lift runs achievable. Belt conveyors are the most commonly used powered conveyors because they are the most versatile and the least expensive. Product is conveyed directly on the belt so both regular and irregular shaped objects, large or small, light and heavy, can be transported successfully. These conveyors should use only the highest quality premium belting products, which reduces belt stretch and results in less maintenance for tension adjustments. Belt conveyors can be used to transport product in a straight line or through changes in elevation or direction. In certain applications they can also be used for static accumulation or cartons.
Advantage Cleanliness The enclosed construction ensures that the material is transported in a dust free and non-polluting way. A high degree of self-cleaning is achieved by the technique applied as well as by the specially designed stations, in particular the tensioning station with its tensioning technique.Cradle conveyor can transport different types of bulk materials without any undue mixing of products or destruction of grains.
Adaptability By using different plant component, it is largely possible to adapt the conveyor arrangement to local conditions, i.e. one plant can be arranged at various operating levels. The arrangement can for instance be horizontal, vertical or circular, or a combination of these. The cradle conveyor Can convey material multi-dimensionally at a time. Change in position can be effected horizontally and or/ vertically by tube bends and /or deflection stations.
Materials The material chosen for the transport discs screwed on support discs to a round link chain depends in particular on the design parameters; i.e. the properties of the material to be transported and the temperature. cradle conveyors are designed for transporting material volumetrically from the inlet to the outlet in the transport tube.
Optimize Conveyor Performance • • • •
Maintain a high level of productivity and efficiency Ensure proper conveyor belt tracking on the conveyor system Increase the life expectancy of wear parts that minimize buildup and corrosion Focus on increasing overall conveyor system efficiency
• • • •
Optimize material flow in direction of travel Minimize impact on the chute and conveyor belt Belt centered throughout the load zone Material center loaded on receiving belt
• • •
Minimize (combustible) dust through curved chute soft loading design Effective skirting and internal wear and impact resistant chute liners Minimize air velocity using staggered dust curtains throughout the loading zone
Eliminating Material Spillage
Dust Control
2
3
Overhead Load Towing Truck Conveyors
This is a floor type conveyor. The difference in this type is that the load to be carried remain in touch with the ground but in the conveyors it is in the suspended state. The load to be carried is placed in to the small trolleys or trucks. These trucks have hooks or vertical mast (rod) which can be attached tothe overhead drive chain.
Different structural members are used as track for overhead trolley- conveyors which include I-beam, double angles, T-rails, steel bars, pipes and fabricated sections. Overhead operation allows free floor space and no interference with equipment or traffic at the floor level. For this reason, trolley conveyors are also called overhead conveyors.
In load towing trolley conveyors the trolleys are permanently secured to the pulling member, and specially designed hooks or rods from the trolley engage and tow floor mounted trucks carrying the load. In this case the conveyor may be made very light as the load in basically carried on the floor, but the advantage of free floor/ working space is lost. This particular type of trolley conveyor is also classified as overhead tow conveyor.
Lifting Equipment Lifting equipment, also known as lifting gear, is a general term for any equipment that can be used for lifting loads. This includes jacks, block and tackle, hoists, rotating screws, gantries, A frames, gin poles, shear legs, sheerleg, windlasses, lifting harnesses, fork lifts, hydraulic lifting pads, air lift bags, and cranes.Lifting equipment can be dangerous to use, and is the subject of safety regulations in most countries.
Jack A jack is a mechanical device used as a lifting device to lift heavy loads or apply great forces. Jacks employ a screw thread or hydraulic cylinder to apply very high linear forces.A mechanical jack is a device which lifts heavy equipment. The most common form is a car jack, floor jack or garage jack which lifts vehicles so that maintenance can be performed. More powerful jacks use hydraulic power to provide more lift over greater distances. Mechanical jacks are usually rated for a maximum lifting capacity (for example, 1.5 tons or 3 tons). Jackscrews are integral to the scissor jack, one of the simplest kinds of car jack still used. The electrical energy is used to power up these car jacks to raise and lower itself automatically. This jack is conventionally known as an electric scissor jack, which is both a time and energy saver. Electric scissor jacks are significantly more efficient than classic scissor jacks in terms of the usability. Less manpower will be needed to operate these modern electric scissor jacks.[ Hydraulic jacks are typically used for shop work, rather than as an emergency jack to be carried with the vehicle. Use of jacks not designed for a specific vehicle requires more than the usual care in selecting ground conditions, the jacking point on the vehicle, and to ensure stability when the jack is extended. Hydraulic jacks are often used to lift elevators in low and medium rise buildings.
Jack screws
Farm jack
1
House jack
A pneumatic jack is a hydraulic jack that is actuated by compressed air - for example, air from a compressor - instead of human work. This eliminates the need for the user to actuate the hydraulic mechanism, saving effort and potentially increasing speed. Sometimes, such jacks are also able to be operated by the normal hydraulic actuation method, thereby retaining functionality, even if a source of compressed air is not available. The farm jack is characterized by rugged, simple construction. It comprises a steel beam with a series of equally spaced holes along its length, and a hand operated mechanism which can be moved from one end of the beam to the other through the use of a pair of climbing pins. The jack's versatility stems from its use for such applications as lifting, winching, clamping, pulling and pushing. It is this versatility, along with the long travel it offers and its relative portability, which make the farm jack so popular with off-road drivers.
Block and tackle A block and tackle is a system of two or more pulleys with a rope or cable threaded between them, usually used to lift or pull heavy loads. The pulleys are assembled together to form blocks and then blocks are paired so that one is fixed and one moves with the load. The rope is threaded, or reeved, through the pulleys to provide mechanical advantage that amplifies that force applied to the rope. A block is a set of pulleys or "sheaves" mounted on a single axle. The assembly of two blocks with a rope threaded through the pulleys is called tackle. A block and tackle system amplifies the tension force in the rope to lift heavy loads. They are common on boats and sailing ships, where tasks are often performed manually
If frictional losses are neglected, the mechanical advantage of a block and tackle is equal to the number of parts in the line that either attach to or run through the moving block -- in other words, the number of supporting ropes. The formula is derived using virtual work in detail in the article "mechanical advantage". 2
Hoist (device) A hoist is a device used for lifting or lowering a load by means of a drum or lift-wheel around which rope or chain wraps. It may be manually operated, electrically or pneumatically driven and may use chain, fiber or wire rope as its lifting medium. The load is attached to the hoist by means of a lifting hook.
Types of Hoist The basic hoist has two important characteristics to define it: Lifting medium and power type. The lifting medium is either wire rope, wrapped around a drum, or load-chain, raised by a pulley with a special profile to engage the chain. The power can be provided by different means. Common means are hydraulics, electrical and air driven motors. More commonly used hoist in today's worldwide market is an electrically powered hoist. These are either the chain type or the wire rope type.
A ratchet lever hoist
Builder's hoist, with small gasoline engine
Nowadays many hoists are package hoists, built as one unit in a single housing, generally designed for ten-year life, but the life calculation is based on an industry standard when calculating actual life. Common small portable hoists are of two main types, the chain hoist or chain block and the wire rope or cable type. Chain hoists may have a lever to actuate the hoist or have a loop of operating chain that one pulls through the block (known traditionally as a chain fall) which then activates the block to take up the main lifting chain. 3
Screw (simple machine) The operation of a screw is that screw shaft rotates, the nut moves linearly along the shaft. This is a type called a lead screw. A screw is a mechanism that converts rotational motion to linear motion, and a torque (rotational force) to a linear force. It is one of the six classical simple machines. The most common form consists of a cylindrical shaft with helical grooves or ridges called threads around the outside. The screw passes through a hole in another object or medium, with threads on the inside of the hole that mesh with the screw's threads.
A screw can amplify force; a small rotational force (torque) on the shaft can exert a large axial force on a load.
Gantry crane Gantry cranes, bridge cranes, and overhead cranes, are all types of cranes which lift objects by a hoist which is fitted in a hoist trolley and can move horizontally on a rail or pair of rails fitted under a beam. An overhead travelling crane, also known as an overhead crane or as a suspended crane, has the ends of the supporting beam, the gantry, resting on wheels running on rails at high level, usually on the parallel side walls of a factory or similar large industrial building, so that the whole crane can move the length of the building, while the hoist can be moved to and from across the width of the building. A gantry crane or portal crane has a similar mechanism supported by uprights, usually with wheels at the foot of the uprights allowing the whole crane to traverse. Some portal cranes may have only a fixed gantry, particularly when they are lifting loads such as railway cargoes that are already easily moved beneath them.
4
Workstation gantry cranes are used to lift and transport smaller items around a working area in a factory or machine shop. Some workstation gantry cranes are equipped with an enclosed track, while others use an I-beam, or other extruded shapes, for the running surface. EOT (Electric Overhead Traveling) Crane This is most common type of overhead crane, found in most factories. As obvious from name, these cranes are electrically operated by a control pendant, radio/IR remote pendant or from an operator cabin attached with the crane itself. Gantry cranes using built-up style hoists are frequently used in modern systems. These built up hoists are used for heavy-duty applications such as steel coil handling and for users desiring long life and better durability.
A-frame An A-frame is a basic structure designed to bear a load in a lightweight economical manner. The simplest form of an A-frame is two similarly sized beams, arranged in a 45-degree or less angle, attached at the top. These materials are often wooden or steel beams attached at the top by rope, welding, gluing, or riveting.
Because they have only two "legs", A-frames are usually set up in rows so that they can have good stability. A saw horse is a good example of this structure. More complex structures will have a cross member connecting the two materials in the middle to prevent the legs from bowing outwards under load, giving the structure the appearance of the capital letter A.
Jin-pole A jin-pole or gin pole (the more common spelling) is a rigid pole with a pulley or Block and tackle on the end used for the purpose of lifting. The lower portion of the gin-pole is set in a shallow hole in the ground and the top secured with three or more guy-wires. The wires or ropes can be manipulated to position the object being lifted or attached to the upper exterior of an existing tower or structure. The gin-pole's free end extends above the location the object is to be lifted.
5
When used to create a segmented tower or antenna, the gin-pole can be detached, raised and re-attached to the just completed segment for the purpose of lifting the next segment. The process is repeated until the top most portion of the tower is completed.
Shear legs Sheers (Shears, Sheer legs, or Shear legs) are a form of two-legged lifting device, that were used by sailboats and dockyards for tasks such as lifting masts and heavier parts of the rigging on board.
Shear legs or simply "shears" are a lifting device related to the Gin pole, Derrick and tripod (lifting device). Shears are an A-frame of any kind of material such as timbers or metal, the feet resting on or in the ground or on a solid surface which will not let them move and the top held in place with Guy-wires or guy ropes simply called "guys". Shear legs only need two guys where a gin pole needs at least three guys.
6
Sheerleg
A sheerleg is a floating crane, but, unlike crane vessels, it is not capable of rotating the crane independently of the ship.
There is huge variety in sheerleg capacity. The smaller cranes start around 50 tons in lifting capacity, with the largest being able to lift over 4000 tons. The bigger sheerlegs usually have their own propulsion system and have a large accommodation facility on board, while smaller units are floating pontoons that need to be towed to their workplace by tugboats. Sheerlegs are commonly used for ship salvage, assistance in shipbuilding, loading and unloading large cargo into ships, and bridge building. They have grown considerably larger over the last decades because of growth, mainly because the components of ships and harbor equipment have grown as well.
Windlass The windlass is an apparatus for moving heavy weights. Typically, a windlass consists of a horizontal cylinder (barrel), which is rotated by the turn of a crank or belt. A winch is affixed to one or both ends, and a cable or rope is wound around the winch, pulling a weight attached to the opposite end.
Forklift truck A forklift truck (also called a lift truck, a fork truck, or a forklift) is a powered industrial truck used to lift and move materials short distances. The forklift was developed in the early 20th century by various companies including the transmission manufacturing company Clark and the hoist company Yale & Towne Manufacturing.
7
Hyster forklift
Electric forklift
Forklifts are rated for loads at a specified maximum weight and a specified forward center of gravity. This information is located on a nameplate provided by the manufacturer, and loads must not exceed these specifications.An important aspect of forklift operation is that most have rear-wheel steering. While this increases maneuverability in tight cornering situations, it differs from a driver’s traditional experience with other wheeled vehicles. While steering, as there is no caster action, it is unnecessary to apply steering force to maintain a constant rate of turn. Forklift hydraulics are controlled with either levers directly manipulating the hydraulic valves, or by electrically controlled actuators, using smaller "finger" levers for control. The latter allows forklift designers more freedom in ergonomical design.
Lifting bag A lifting bag is an item of diving equipment consisting of a robust and air-tight bag with straps, which is used to lift heavy objects underwater by means of the bag's buoyancy. The heavy object can either be moved horizontally underwater by the diver or sent unaccompanied to the surface. Besides as a piece of diving equipment there are also lifting bags used on land for lifting cars or heavy loads or lifting bags which are used in machines. These lifting bags of the AS/CR type are for example used in the brake mechanism of rollercoasters. It is advisable to select a lift bag with an appropriate capacity for the task at hand. If the lift bag is grossly oversized a runaway or otherwise out of control ascent may result. Commercially available lifting bags may also incorporate dump valves to allow the operator to control the bags buoyancy during ascent.
8
Lift bag
Open lift bag
Closed lift bag
If a single bag is insufficient, multiple bags may be used, and should be distributed to suit the load.Lift bags are used to bring the load up in stages: a long chain or sling is used to connect the cago to a lift bag at a shallower depth, which is filled to lift the load until the bag reaches the surface, then a second bag is used to bring the load up further. The lift is controlled by a line from the surface vessel, and the load is reduced by a lift bag with a volume too small to support the weight of the load when full. This allows a faster lift by the winch. The lifting gear must be capable of supporting the load if the bag fails, or must be arranged to fail safely.
Occupational safety and health Occupational safety and health (OSH) (also commonly referred to as occupational health and safety (OHS) or workplace health and safety (WHS) is an area concerned with protecting the safety, health and welfare of people engaged in work or employment. The goals of occupational safety and health programs include to foster a safe and healthy work environment.OSH may also protect co-workers, family members, employers, customers, and many others who might be affected by the workplace environment. In the United States the term occupational health and safety is referred to as occupational health and occupational and non-occupational safety and includes safety for activities outside of work. Occupational safety and health can be important for moral, legal, and financial reasons. All organisations have a duty of care to ensure that employees and any other person who may be affected by the companies undertaking remain safe at all times. Moral obligations would involve the protection of employee's lives and health. Legal reasons for OSH practices relate to the preventative, punitive and compensatory effects of laws that protect worker's safety and health. OSH can also reduce employee injury and illness related costs, including medical care, sick leave and disability benefit costs.
9
OVERHEAD CONVEYOR An overhead conveyor describes all conveyors with roof-mounted drives. They are known as overhead conveyors because load is carried on the moving carriages which move on overhead tracks. In simple manner loads can be transported by carriers running on rails suspended from the roof or carried on the floor by vehicles with roof level drives. They can be used for any complicated configuration and are restricted to in house handling. DESIGN DETAILS The main parts of this of conveyors are Rail : It is mounted on the roof and is used to support the rollers or wheels which run over it. Carrier : One end of this contains rollers and at the other end it holds attachment Drive : Depending on the load and configuration. It is selected chain drive is popular. Power is supplied by electric motors. Suspension Attachment : This type of attachment depends on geometry of load and its properties. Speed Controller : Gear drives are used to vary the speed or variable speed motors are used and chain Tensioner Overhead Tracks : The track of overhead conveyors is made of rolled or bent sections of steel. Generally I beam sections are used. TYPES OF OVERHEAD CONVEYOR Overhead conveyors may be divided into three main types, depending on the drive method. The usual method is by chain. Worm drives and self-powered carriers are two other options. Chain operated overhead Conveyors come in two main designs : Continuous direct or with a disengaging feature via a separate chain fitted with drive dogs to facilitate accumulationswitching etc.
Depending on the ethod of onnection of hauling or driving chain with load carrying trolley attachment and the method by which the load is moved they can be divided as 1.overhead load carrying trolley conveyors. 2. overhead pusher conveyors 3. overhead push-carrying conveyor 4. overhead load-towing conveyors 1
5. overhead low-carrying truck conveyors OVERHEAD LOAD CARRYING TROLLEY CONVEYORS In this trolley with load carrying attachment are fastened or attached to the drive chain and move on the overhead track, while the chain moves along that track. In other words wheels and attachment is connected to a chain. It carries endless driving or hauling chain
OVERHEAD PUSHER CONVEYORS OR POWER AND FREE CONVEYORS In this type chain and trolley runs on separate track. Chain is on one track and trolley is on another track. Compared to the above design it is complicated but load carrying capacity is more.
OVERHEAD PUSH CARRYING CONVEYORS This is essentially a combination of above 2 types. The load is moved by pushing the chain manually or mechanically. It is provided with the hooks which are attached to the chain, these are used to connect with the attachment which carries the load.
2
OVERHEAD LOAD TOWING (FLOOR TYRE) TRUCK CONVEYORS The difference in this type is that the load to be carried remains in touch with the ground but in the other conveyors it is in the suspended satate. The load to be carried is placed in to the small trolleys or trucks. These trucks have hooks or vertical mast which can be attached to the overhead drive chain. OVERHEAD LOAD TOW-CARRYING TRUCK CONVEYORS The only change in this is that the floor trucks can be attached to the trolleys or directly to the chain. In this truck moves in the combined motion means in some portion of conveyor line it is to the ground and in some portion it is moved in the suspended state. SPECIFICATION OF OVERHEAD CONVEYOR These conveyors are specified as load per carrier, speed and curve radius. Load per carrier
= 25 to 1500kg
Speed
= 10 to 100m/min
Curve Radius
= It is given in horizontal and vertical terms usually in mm
ADVANTAGES OF OVERHEAD CONVEYOR • • • • • • •
Free floor area Layout simplicity Sample Design Low investment Any complicated path can be designed Better adaptability to the production process Low power consumption
DISADVANTAGES OF OVERHEAD CONVEYOR • • • •
Limited headroom Roof must have load bearing capacity Speed of operation is slow Risk of accidents due to moving overhead loads APPLICATIONS OF OVERHEAD CONVEYOR
The most extensive use of overhead conveyors is in industry, particularly in assembly operations where both basic assemblies and components are moved 3
in a way that leaves the floor area free for traffic etc.. some specific application are listed below: a) b) c) d) e)
Transporing castings,forgings and assembly units in shops and between them. Transporing machine parts between machine tools Transporing mould cores to mould assembly Transporing sub assemblies between stations Extensively used in foundry, automobile and assenmbly lines
ADDITIONAL FIGURES
4
Different Types of Material Handling Equipment Material handling equipment encompasses a diverse range of tools, vehicles, storage units, appliances and accessories involved in transporting, storing, controlling, enumerating and protecting products at any stage of manufacturing, distribution consumption or disposal. Categories of Material Handling Equipment The four main categories of material handling equipment include: storage, engineered systems, industrial trucks and bulk material handling. Storage and Handling Equipment Storage equipment is usually limited to non-automated examples, which are grouped in with engineered systems. Storage equipment is used to hold or buffer materials during “downtimes,” or times when they are not being transported. These periods could refer to temporary pauses during long-term transportation or long-term storage designed to allow the buildup of stock. The majority of storage equipment refers to pallets, shelves or racks onto which materials may be stacked in an orderly manner to await transportation or consumption. Many companies have investigated increased efficiency possibilities in storage equipment by designing proprietary packaging that allows materials or products of a certain type to conserve space while in inventory.
Examples of storage and handling equipment include:
1
•
Racks, such as pallet racks, drive-through or drive-in racks, push-back racks, and sliding racks
•
Stacking frames
•
Shelves, bins and drawers
•
Mezzanines
Engineered Systems Engineered systems cover a variety of units that work cohesively to enable storage and transportation. They are often automated. A good example of an engineered system is an Automated Storage and Retrieval System, often abbreviated AS/RS, which is a large automated organizational structure involving racks, aisles and shelves accessible by a “shuttle” system of retrieval. The shuttle system is a mechanized cherry picker that can be used by a worker or can perform fully automated functions to quickly locate a storage item’s location and quickly retrieve it for other uses. Other types of engineered systems include:
•
Conveyor systems
•
Robotic delivery systems
•
Automatic guided vehicles (AGV)
Industrial Trucks Industrial trucks refer to the different kinds of transportation items and vehicles used to move materials and products in materials handling. These transportation devices can include small handoperated trucks, pallet-jacks, and various kinds of forklifts. These trucks have a variety of characteristics to make them suitable for different operations. Some trucks have forks, as in a forklift, or a flat surface with which to lift items, while some trucks require a separate 2
piece of equipment for loading. Trucks can also be manual or powered lift and operation can be walk or ride, requiring a user to manually push them or to ride along on the truck. A stack truck can be used to stack items, while a non-stack truck is typically used for transportation and not for loading. There are many types of industrial trucks: •
Hand trucks
•
Pallet jacks
•
Pallet trucks
•
Walkie stackers
•
Platform trucks
•
Order picker
•
Sideloader
•
Many types of AGV
Bulk Material Handling Equipment Bulk material handling refers to the storing, transportation and control of materials in loose bulk form. These materials can include food, liquid, or minerals, among others. Generally, these pieces of equipment deal with the items in loose form, such as conveyor belts or elevators designed to move large quantities of material, or in 3
packaged form, through the use of drums and hoppers.
•
Conveyor belts
•
Stackers
•
Reclaimers
•
Bucket elevators
•
Grain elevators
•
Hoppers
•
Silos
Other Materials Handling Guides • • •
Common Types of Pallet Racks Drum Liners Buying Guide Food Containers Buying Guide
Applications of Material Handling Equipments
Trucks and Mobile Lifting Aids Trucks and mobile lifting aids perform a large percentage of material handling in modern workshops. The applications shown here are just a few examples of what products and solutions Thomson has to offer. Let us know your specific needs, and we can tell you more about our products and services, and of the many advantages of using Thomson as your supplier.
4
Rodless Actuators Thomson rodless actuators are selfsupporting and lightweight, so they’re easy to move. And because there’s no need for covers or any load-supporting framework, you’ll find assembly to be simple and quick.
Electromechanical Brake A fail-safe Deltran electromechanical brake is used as a parking brake.
Electric Linear Actuator Our heavy duty linear actuators are rugged for the toughest, basic jobs and also available in high precision configurations. Options and accessories such as position feedback, limit switches and controls provide great flexibility.
5
Car Chassis Transportation Material handling solutions sometimes involve bringing together production cells that can’t be placed adjacent to each other. Moving goods, parts or components between these cells means covering distances with speed, but without getting in the way of other processes. Overhead transportation is one way to achieve this goal, as goods will not interfere with walkways or truck routes, keeping valuable floor space free for other production equipment.
Adjustable Picking Tool The use of linear actuators, precision linear actuators and round rail Ball Bushing® bearings makes this tool adjustable, allowing you to pick different types of chassis in a mixed production line.
Long Transport Systems Thomson has a variety of systems with the capacity to move objects long distances with high speed. In this application an entire car chassis is moved 12 meters in a couple of seconds.
6
Workspace Expansion By mounting the base of a robot onto a combination of linear guides, ball screw and Micron planetary gear, any workspace can be dramatically enlarged. The robot can also perform work on a moving chassis.
Lifting Unit •
The telescopic lifting unit is an ideal addition to the Tollobelt system. The telescopic function allows the system to be mounted close to the ceiling, since the lifting unit can reach down and lift
Vertical Lift Module - Automatic Storage Moving materials in and out of storage can often create major logistical challenges. In fact, simply finding the right item at the right time can be the biggest hurdle. An automatic storage system, such as a vertical lift module (VLM) shown here, can be a solution. This type of automated storage system features a computer-controlled mechanism that stores and keeps track of items. The challenge for such a system is to be able to handle items quickly while maximizing the storage area. Thomson has several standard products that are well-suited to this type of application, as well as the ability to design a customized solution if needed.
7
Shelf Picking System The vertical movement of the shelf picker is carried out by two lead screws, guided by four profile rail linear guides. The horizontal movement also uses two lead screws and four profile rails, configured so that the shelf picker can pick from the shelf stacks at both the front and the back.
Shelf Positioner Here, two linear motion systems work parallel to each other moving shelves in and out of the VLM. Their small size, minimal maintenance requirements and high resistance to dirt and dust makes them a good choice for this exposed location.
Food Container Palletizing The food industry places high demands on material handling equipment. Harsh conditions found in places such as dairies, bakeries and breweries means equipment is often exposed to extreme temperatures, as well as water, moisture, dirt and cleaning agents. Plus, equipment must be fast and accurate to keep up with high speed production lines, yet must also be easy to clean and maintain so it won’t contaminate the environment or the food. Whatever your particular food handling challenge may be, Thomson has the products and know-how to get the job done.
8
Linear Unit Systems Few linear unit systems offer the variety of sizes and technologies as Thomson. We create systems specifically designed and built to deliver the kind of performance, durability and safety needed for your specific application.
Precison Linear Actuators Replacing hydralic and pneumatic solutions with electric Precision Linear Actuators provides higher speed, better accuracy, improved controllability, lower noise and reduced energy consumption.
Micron AquaTrue Planetary Gearheads The AquaTrue series, designed specifically for the food processing industry, has both the accuracy and toughness necessary for optimal performance. A wide range of gear ratios and frame sizes make AquaTrue easy to implement in most types of machines.
9
Assembly Line Engine Handling
An assembly line requires a steady flow of materials to specific assembly points along the line. An overhead conveyor system is a convenient solution, in that it does not occupy any floor space, yet can still transport materials a great distance. Such a system can also be used when its necessary to position assembly tools and equipment. The main challenge is that the quick pace normally found on an assembly line requires such systems to be lightweight, to make it possible for operators to move the equipment quickly and accurately and lower the risk of fatigue and injuries. Thomson has pioneered a family of products and services to meet the challenge.
The Movorail System The Movorail system has been a mainstay of the automotive industry for more than twenty years. Movorail is a lightweight, maintenance-free, modular crane rail system that comes in four sizes for loads up to 600 kg per rail. Due to its modularity and broad range of accessories, it is possible to build just about any imaginable type of conveyor or crane rail system. All you need to mount it is a few common tools, making the system easy to reconfigure or move to another location if neccessary.
Movorail with Telescopic Crane Rail In this Movorail system, a telescopic crane rail is mounted so that it can move a power tool over the hood of a car. When the work is done it can be pushed back to a neutral position allowing the car to pass.
Movorail Conveyor System Almost any type of conveyor system can be easily built with Movorail rails. Motorized trolleys can carry up to 600 kg. Plus, the system includes curves, switches and turntables, making it possible to bring materials from multiple locations to an assembly point.
Lifting Devices
10
Thomson has several units designed for lifting operations. In this case the telescopic lifting unit Movoz Z3 is suspended in a Movorail system. The lifting movement is motorized while the X and Y movements can be manual or motorized. In this application, the operator picks an engine from the conveyor system with a custom made tool attached to the bottom of the lifting unit, rotates it 180 degrees and then positions it in the engine compartment of the chassis, all while the car on the conveyor keeps moving forward.
Aircraft Wing Handling Few industries place as much demand on a handling system as aircraft construction. The handling of very large and heavy objects, the need for extreme accuracy and unyielding quality standards make for a difficult challenge. At Thomson, we have both the unique experience and the products to meet the precise needs of the most demanding material handling applications.
Aircraft Wing Handling In this instance, a wing is transported along a line. At a machining assembly station, the oversized and immensely heavy wing is brought in and tilted 90 degrees. The sheer size and weight of the wing makes the job particularly challenging.
Round Way Roller Bearings Round Way Roller Bearings have the strength and accuracy to be able to transport an entire wing along the line. Unlike most linear bearings, Round Way are very forgiving. For instance, the bearings can pass from one shaft to another without losing accuracy, even if they are not perfectly aligned. This makes it possible to build large systems quickly and easily.
Tilt Station Transport Platform
11
To get the wing in and out of the tilt station, the wing fixture is brought on to a transport platform. The platform rides on a set of Round Way bearings and is moved in and out of the tilt station by a ball screw assembly that includes a Micron planetary gearhead. This combination allows the wing to be correctly positioned with accuracy high enough to allow for machining.
Tilt Station with Screw Jacks Once the tilt station transport platform is correctly positioned in the tilt station, three Thomson worm gear screw jacks tilt the wing and the platform 90 degrees. In this position, machining and assembly work can be carried out on the wing. The screw jacks are easy to synchronize, have high accuracy and efficiency, and have proven to be quite rugged and reliable.
12
Tow Conveyor Unit + In-Floor + Accumulate Uses towline to provide power to wheeled carriers such as trucks, dollies, or carts that move along the floor Used for fixed-path travel of carriers (each of which has variable path capabilities when disengaged from the towline) Towline can be located either overhead, flush with the floor, or in the floor Selector-pin or pusher-dog arrangements can be used to allow automatic switching (power or spur lines) Generally used when long distance and high frequency moves are required
Tow conveyors may be overhead trolley cars or floor conveyors adapted for handling dollies, trucks, and cars, which are locked into the towing chain to be moved from any point in the system to any other point.
1
Towline conveyors can be used in a wide variety of applications where it is advantageous to carry the product on a mobile cart. Some products are considered "unconveyable" due to their shape, configuration or size. A typical example would be large four-legged furniture items. The PAC-TRAK™ form PACLINE utilizes mobile carts, normally with a rotating top, onto which the item to be conveyed is placed. A variety of floor-mounted conveyors are used to propel the cart through the process, depending on the loading, speed and preferred configuration. The PAC-TRAK™ Towline Conveyor system can be designed with onfloor or in-floor tracks. On-floor conveyors are attached to the floor surface without trenching. In this case, plant personnel must walk over the track, and forklifts will not be allowed to drive in the area of the conveyor. The drive unit may be situated in a "pit" or mounted above the floor. If mounted above the floor, provisions must be made where the cart crosses the conveyor path. Other features: • Standard 4-wheeled cart is propelled by a drive chain. • Towline track can be in-floor or on-floor mounted with minimal cross section height. • Top platens can be custom designed based on size, shape and weight of the item being conveyed. • Platens can be rotated manually or automatically for close packing. • Reliable conveyor chain used with ball bearing wheels instead of "link" chain to reduce maintenance.
HIGHLY EFFICIENT HANDLING FOR A WIDE RANGE OF PRODUCTS • The standard four-wheeled cart is propelled by a drive chain. • The system can be mounted “in floor” or “on floor” with minimal cross section height. • Platens can be rotated manually for easy access to all sides by operators. • Platens can also be rotated automatically for close-packing in accumulation zones. • Capacity is scalable from 1 lb. to 30,000 lbs. on the same conveyor. 2
TOUGH, RELIABLE CONVEYOR CHAIN AND TRACK • PACLINE PAC-TRAKTM towline system uses reliable conveyor chain with ball bearing wheels instead of “link” chains to reduce wear and eliminate maintenance. • Curves are hardened to increase wear resistance. CUSTOM DESIGN FEATURES • The PAC-TRAKTM cart can be fitted with top platens of various sizes and can be custom designed based on the size, shape and weight of the products carried. • The PAC-TRAKTM track system can be custom designed to accommodate your specific paint line or assembly line requirements.
3
01234 15673852 9
!"
# ! $
%
& '
' !" ' 9 (
'' ! " '
'
!" ' ' !) ''
'
! $ ' ' !* '
!9
' '
! " '
' !
+0 30 , ''
' !-
' ' ( '' !)
' !9 ' . !9
' ' '
' ! 9
' ' ' !"
'
' '
# !9
' #
# #' !9
' ' '' / !9
0 ' ' 1 #' ! $ * * " 2 '
!
OSCILLATING CONVEYOR OSCILLATING CONVEYORS are utilized to convey sand or other granular particles at a desired rate. The conveyor is generally placed under a vibrating shakeout or a grid to eliminate direct handling of hot sand by the belt conveyor. In the process of reciprocation, the oscillating conveyor cools the hot sand to some extent which Increases the life of the return sand conveyor belt.
CONSTRUCTION The equipment comprises a metallic trough carried on inclined arms which are fitted with rubber bushes to handle the reciprocating motion of the trough. The oscillating motion of the trough is achieved via specially designed inclined arms and an eccentric shaft driven by a motor through V-belts.
OPERATION The eccentric shaft is mounted on anti-friction bearings and has V-pulleys at both ends with weights on them to counteract the unbalancing force. The rotation of the eccentric shaft provides a forward and backward motion to a connecting arm attached to the trough through a rubberized pin. A retaining spring assembly at the back of the trough absorbs shock load.
selection of vibratory conveyor: 1
The oscillating motion of the trough is achieved via specially designed inclined arms and an eccentric shaft driven by a motor through V-belts. The eccentric shaft is mounted on anti friction bearings and has V-pulleys at both ends with weights on them to counteract the unbalancing force. The rotation of the eccentric shaft provides a forward and backward motion to a connecting arm attached to the trough through a rubberized pin. The trough motion is predominantly horizontal with some vertical component, which causes it to oscillate with a pattern conductive to conveying material. A retaining spring assembly at the back of the trough absorbs shock load. All components including drive motor are mounted on a rigidly constructed base frame.
Advantages: · Hot and abrasive materials can be handled · Cooling, drying and de-watering operation can be done during transport 2
· Scalping, screening or picking can be done · Units can be covered and made dust tight · Simple construction and low head room · Can be made leak proof
Disadvantages: · Relatively short length of conveying ( about 50m Maximum) · Limited capacity, about 350 tons per hour for length of conveying of 30 m. · Some degradation of material takes place.
Applications: Vibratory conveyors find wide spread application in the transportation of dusty, hot, toxic, and chemically aggressive bulk material through a closed trough or pipe in chemical, metallurgical, mining industries and manufacturing of building materials. Vibratory conveyors are also employed for transportation of steel chips in machine shop, hot knocked out sand, wastes and small castings in foundry shop. Vibratory feeders are also in use for delivery of small machine parts like screws, rivets etc. Sticky materials like wet clay or sand are unsuitable for vibratory conveyors. In handling finely pulverized materials, like cement etc., the performance of such conveyors are reported to be poor. Vibratory conveyors are hardly employed for handling common bulk loads, such as sand, gravel, coal etc as the same can be done more efficiency by belt conveyors.
3
012230516738109
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` )$# (#',% ' '&" (* #'.+ ,% &'&'! #&)*& $- ( % )&' +&1 # ! " #) $# * /& #'! "'1)* '.$'& )*#'0 4#1 %# % ##% )&#& ! ")&' #( , 0 4'.#&)&' & ) &1 2: % 0 * ! " #) (& $# *)#)#& '.% )&( , )*)##$ 1) (& & , *)#II aI 251 # ) ) # $# *'#& #)##& '.) 4#)*' )*'.-)"#( )*'.b$ )*'.,)& ') #( , )'). #2. & # % ,)"- % !'* *'
0124567285905 572 26050125 56 29529122 92 !2 054567285 6562 9240 5656812456728594 61 72 4!972 240 560541 6"2 9240 56# 029 572 260$20%2260%5272 8$2 562$8 6 64 62 59 & 9 8 59 2 "9 7 0895294567285912& 9 59 6492 201226"01501245672859 6 01292$8 4560950127254 085012 90 42 57 6" 5%601245672859'08& 4 !6&5%292 9529 45672859 15%6 6( "
) *2629 7 2%5 6!6&5%292 952945672859
0 123456768 4 67 42 647
0 !"
#$%&'()*(+,-)./%/0(%)11/%(2),3/4)% 56789:;;<=>?@ABCDEFGDHIC8GJCCKGL8IGK8MKEKGICCB8NLKF8OPDHP8IGK8QIFK8RGJQ8STU8LVKKC8WDWKL8ODVP HILV8JG8RIXGDHIVKF8KEF8RCIEMKL8VJ8IHHJQQJFIVK8VPK8IEVDRGDHVDJE8XKIGDEML85NLNICCB8XICC XKIGDEML7Y8ZPK8VPGJNMP8I[CKL8IGK8LVIVDJEIGB8IEF8GJCCKG8XIGGKCL8HIE8GJVIVK8RGKKCBY8ZPKLK8GJCCKGL
012405526765211855219
8148 27 457 617405824961972918 6922501924 6852021261855219 812251855219012926
298 8212648 2811855219 457 617405 685202126 !225 26702218 21855219622 68 26702218 90 601692257290 0750520 6
01 1808"#80$%&& '20 721258068248 22650121670221 0 620 72105574( 2998 218552190124892 740597)298 9828 218552190 6 2712740117 400477290127 2 7 2 85587 052
*8552174622 698 252 0 6278 258060 6526 2 758069856 2 981260520981855219920$77498562+,-.%/"8 2580652 818869 5 21052821(9/90(7 185521742005818%/& 8 52 8 58068248 9762126
2234 5678 102790018 248 2818 7421855210$5291290 6012 7$268 2
01234516869 4 89 6 094861 9241609224 40 12 4614694 9644 2 1 0 248924 184869 4494 96489 90 249442 19494 121 6194 24 1 9 134 4218494 964643424 5 2 2 161094 1649356146 494 95 48 4124869 4 509 5 09 46146
496 28 2 924 6990 4214869 4 1 2 2
146 18 493592 !469493554 " 496 95 4613 4912 144 184869 4164342 134 42184 19 451246146 92" 496 96496 09652404 965940634 40 12 18901234516 "92 1664 4 #"92 1664 4 16401234516869 4 61469 4
4 861 4612"92 96442469589 6 094861 4 16 6069 40 12 613 1281661 21248116$4 18 92 96401 42144496 04 99 012342 4243412401234516 " 9169 401234516 184293444 01 24 8164 92 094 20 29 12 18401234516 092 4 9 59% 4 2 "40 94 2 &84964 2
461884964 092 4 20161694 29221 464012345161 9 85 884642 820 129 64' 64 42 "1 4184 49644 06 4 41 (1 4)61 614601234516# 4 2 41012345 492493519 *2 9041812412926116 12945964 9 4466146 1 946 9 4466146 42 4 929818496466146964 41 164 224642 1849 6 186146 9 129 16869 4 64' 64 4 2 16 11 40494692 4 9 4 012342 129 2461 01234516 12469296466146
0112456789 8 1 8 8685 89 6 19168 1 8 78 61 8 61 8 1 8 1 6 86 686689691 6 685 86 1961 6 86 685 891 8 86 86 6895 8 191 1 8 9 6 86
0 88 1 2!11 5 191 1 8 9 6 86 8 18789 5 1
18 86896 860"#6 862$ 5 8 868 8 986
19 1 6 689
8 1 $68 9 89 5 89 01112%1 8 &871 8 5 8916 86 78 6 8 8 6 9168 1 8 9 6 91786 8 96 8 78 668 89 1 8 &1868 8 1 8 688 89$
8 1 68 '()*+,(-./010 88 1 21 5 89 6 6 8661 96 86 86 78 6
19165 6 86891 566 86 78 61 1 8 0825
6 1 86 819 8 1 78 62 6 86 78 6 5 89 86 81 1 1389 786 1 5 89 861 4 8 8 9 8 8 56# 8$ 8 56 8 86 890 5 6 6 86 8 1 2 8 98 168989 8 9 86 89 786 898 168965 '56+708190:(6;+11 8 1 8 78 61 1 189 889 1 86 8< 9 8 1 78 6$9 81 895 =8
8 6 5 8 78 618
> 86896 86 78 6 1 56789 8 1 ?$ 56# 8@$189 8 1 A '66 886 86 178189 0 6882685 89198898 6 6 6 86 78 68681 1 8 8
6 78 8 91 9168 1 &88 61 681=8 8 1 89 1 591 786 8 78 6 =1
012346708940 09344 41480 0 0 019 14 74741430 01 434 4714 441480 01 30 1 14 0 434 912430
047
34 414148 0 434701 30 4 1 34148 01 7477138 44
334148 01 4 12038 6 !"#$%&'4 404 304 0441 4148 8 0338 471230
703312414841 ()%*$$+*,)-.'%"#$%'70894 304 0 4 4 1474 04 1 14 00334148 4712034 0 1 / 40 4 4 04 7 3430 443 304 4 12 342 4 148
4 0 4012 7089474 174 3443433498
09347401 7 612#3+,+4'5#66+,'7#-8+9#, :-",#4;<")#-&'=10 44 334148/03 0334 > ?@ABCC?D@EBF?GBD/03304 4334 04 4198147 3 347 20
04 01 7
1 8 47 430
143341480474 98410340 4 94441430
01 4 41334 12430
H44 334148 04141 438 4 1408 4
301 3I43312733 44
40801 074 74030I4 43487473301 0 4 4
40 741 4334148 0194D??DJ FK@8 4 4 4
70894L1M44 128 4 01 70403 14 2*,"%'#N'$#3+,+4',#66+,'<#-8+9#,% 6 5#66+,%&'4334 0 44 148 1 07410338 4417 401 1 44 148104904301 4 0 10414203 0480194
419811412 44 041
414203 0 047 14 194012 4 14074 0 4 4 404474 0 4,)8+-',#66+,% 4 41334 0424140338 9 44 1 409347 030 6 40338444 12 8 4 4
12148 01 414480470 4 124 4334 019470 47 3 443212 0 12 01940904 7 408 41 94 01 3 0 /7014 0334 4 001 8107 90301124 0744 0194081294441OPPQPP773340934 4 1 408 30993712733 / 1RSPTSP77241403 801 12 148 U334 4344 0430 4 980340 41334 441 02212430 94441 41334 /11 44 6 34334 70894 1 4 94441 41334 6 V,*W+%&'4334 04 4 04 103 1 4074 041
4 074 041144 984084
70I407 4074 4 0934 2 1241480741 1 01X0408 8148/4074I 033870 470 443/01 0324 8148/4074 708940904
012312556789665 5 968 786 92 868 209601 3685 16576 6 72 96 7168896363 5267 ! "# $ %21 5 880 92 20 2&6167125561 2 6218' 8672 969 6 20716 11 636 963 5267 (6 2 632921716832169 2 621 5596716 1255618)98 5567*+,- 21.,/"-/ 0 1 122 716)6 61 552 52 632921&9829 '5691 83882 11 636 98 286792716 5596716 1255618321 52 2 621)2101232961 2 8761 92 8)3216 9 2 6329213 '62867)6 71 122 201255618 700616 986 92 82096
2 6214691 83882 20 2&610123963292192961255618 1&76576 6 7 2 2861 6 729 2 516618 2 621)'6656 191 83882 11 636 93 '628674632921)9122 6 1'267168 8 09 5 67 52 9656 92096716 8762096 2 62172&6192 55961255618 169122869209&2'6656 18 882& 3889467168 09&982
219 '6 1 8 796'6656 18 1622867 96 '2601 36) 7 19 553361867 2502152'1 92 1 5961 96768 96:91 83882 20 2&613 236922 6125561) 7962961716 12556183 '6 2 6 967 9298716 125561'86168208 12 ;698 7 8
1 59729 2&6167125561 2 621)9612556183 '6716 '2 66 7568805 9'659 716 '652&961255618) 782
21967'756125561882 9 996'659922 68 5596 1255618 791 839 2&6192963'01 92 488)2 5;629618) 29 2896716 (6 6 2096716 1255618 16716 ' 772 532921)98 5567 00, / 0 46863292183 '68 66732921891 8399 3292 9122 1672 6 13888<5961 965)8 6 55768 67852&8 6672552&129218 09329218 162867& 16716 95 22 56792961255618 09(996 5 '5920'69961656 91 5
2 9125889638) 772 55716 125561 2 6218 16699 3216 2 25 1 19 25 15 02116618 729
012456789 5
6 5 56 0 2 !"" # $ %" &% '' "( ) $* ! %! " %%+ % & "!"%& %"%&! ,() *" "" # $ $* %" %# (-# ! & %" * "% * %*# (
Hydraulic Lift
There are two types of Hydraulic Scissor Lifts. Mobile Hydraulic Scissor LiftMounted on Nylon wheels. Stationery Hydraulic Scissor Lift Pit Mounted. Hydraulic Scissor Lift Table is designed to meet the high quality, reliability and ease of handling . The table is designed based on the customer requirement. The speed and the efficiency with lifting and lowering of table are being done by a pair of hydraulic cylinders actuated by power pack. Application The Scissor are used for applications like Die Loader, Dock Leveller, Loading Platform, Working platform, Transfer materials from one place to another. Key Attributes • •
High quality, Reliability and ease of handling. Working parts are enclosed and engineered for maximum efficiency for easy maintenance and trouble free working.
Standard hydraulic lift systems are ideal for ergonomic lifting and moving of materials in both industrial and commercial sectors. These products are utilized in every facet of manufacturing, production, processing, storage and warehousing. We can customize any of these products to suit your specific need or function. Hydropower prides itself on building material handling products that meet your needs. We have designed and engineered custom lifts for small and medium scale industries.
1
HYDRAULIC CONVEYORS Hydraulic Winch
Winch is a stationary motor-driven or hand-powered machine that is used for hoisting or hauling, having a drum around which is wound a rope or chain attached to the load being moved. A hydraulic winch is driven by a hydraulic pump, the fluid pressure coming from a hydraulic Power Pack driven by the main engine or electrical motor.
Hydraulically operated winch is ideal for all types of specialized transport from low-bed operations to wrecker’s equipment and can be set up to operate either singly or in combinations. They are reliable, rugged and built to last with user friendly simple lever operated controls. They are an excellent addition to crawlers, skidders and all-terrain vehicles. The stationary usage is also possible. The hydraulic winches can also be clutch-operated that makes for an easier and safer usage.
Hydropower offers a line of Hydraulic Instrument Winches. These range in size from 2 to 5 HP. All of our hydraulic winches offer the following features: •
• • • • •
•
Separate winch and HPU units allows HPU to be used for other purposes, if required Variable speed control Focal slip rings Powder-coated finish Stainless steel fasteners Accept steel, stainless steel and synthetic fiber mechanical and E-M cable types Fully factory tested and ready to run
HYDRAULIC CONVEYORS Electro-hydraulic instrument winches are used for numerous applications including on-station deployment of various payloads including CTDs, free-fall profiling, towing of side scan sonar, magnetometers, plankton nets and others. • • • • • • • •
Steel fabricated cable drum and winch base for maximum rigidity High efficiency planetary gear drive modules for optimum performance Multi-Disc, wet, friction brake for dependable holding High capacity sprig clutch for reliability Gearing and brake unit are located outside the cable drum for versatility Brake valve is the industry's most stable for controlled dynamic braking Cable drum supported on roller bearings Wide range of motors and mounts to suit specific application.
HYDRAULIC CONVEYORS
PLANNING PRINCIPLE
The Ten Principles of Material Handling
All material handling should be the result of a deliberate plan where the needs, performance objectives and functional specification of the proposed methods are completely defined at the outset.
The Key to Greater Productivity, Customer Service and Profitability
PLANNING PRINCIPLE PLANNING PRINCIPLE
Definition: A plan is a prescribed course of action that is defined in advance of implementation. In its simplest form a material handing plan defines the material (what) and the moves (when and where); together they define the method (how and who).
Key Points The plan should be developed in consultation between the planner(s) and all who will use and benefit from the equipment to be employed. Success in planning large scale material handling projects generally requires a team approach involving suppliers, consultants when appropriate, and end user specialists from management, engineering, computer and information systems, finance and operations.
PLANNING PRINCIPLE
PLANNING PRINCIPLE
KEY POINTS
KEY POINTS
The material handling plan should reflect the strategic objectives of the organization as well as the more immediate needs. The plan should document existing methods and problems, physical and economic constraints, and future requirements and goals.
The plan should promote concurrent engineering of product, process design, process layout, and material handling methods, as opposed to independent and sequential design practices.
STANDARDIZATION PRINCIPLE
STANDARDIZATION PRINCIPLE
Material handling methods, equipment, controls and software should be standardized within the limits of achieving overall performance objectives and without sacrificing needed flexibility , modularity and throughput.
Definition: Standardization means less variety and customization in the methods and equipment employed.
STANDARDIZATION PRINCIPLE
STANDARDIZATION PRINCIPLE
Key Points
Key Points
The planner should select methods and equipment that can perform a variety of tasks under a variety of operating conditions and in anticipation of changing future requirements.
Standardization, flexibility and modularity must not be incompatible
Standardization applies to sizes of containers and other load forming components as well as operating procedures and equipment.
WORK PRINCIPLE
WORK PRINCIPLE
Material handling work should be minimized without sacrificing productivity or the level of service required of the operation.
Definition: The measure of work is material handling flow (volume, weight or count per unit of time) multiplied by the distance moved.
WORK PRINCIPLE
WORK PRINCIPLE
Key Points
Key Points
Simplifying processes by reducing, combining, shortening or eliminating unnecessary moves will reduce work. Consider each pickup and set-down, or placing material in and out of storage, as distinct moves and components of the distance moved.
Process methods, operation sequences and process/equipment layouts should be prepared that support the work minimization objective. Where possible, gravity should be used to move materials or to assist in their movement while respecting consideration of safety and the potential for product damage.
WORK PRINCIPLE Key Points
The shortest distance between two points is a straight line.
ERGONOMIC PRINCIPLE
Human capabilities and limitations must be recognized and respected in the design of material handling tasks and equipment to ensure safe and effective operations.
ERGONOMIC PRINCIPLE ERGONOMIC PRINCIPLE
Definition: Ergonomics is the science that seeks to adapt work or working conditions to suit the abilities of the worker.
Key Points Equipment should be selected that eliminates repetitive and strenuous manual labor and which effectively interacts with human operators and users. The ergonomic principle embraces both physical and mental tasks. The material handling workplace and the equipment employed to assist in that work must be designed so they are safe for people.
UNIT LOAD PRINCIPLE
Unit loads shall be appropriately sized and configured in a way which achieves the material flow and inventory objectives at each stage in the supply chain.
UNIT LOAD PRINCIPLE
Definition: A unit load is one that can be stored or moved as a single entity at one time, such as a pallet, container or tote, regardless of the number of individual items that make up the load.
UNIT LOAD PRINCIPLE
UNIT LOAD PRINCIPLE
Key Points
Key Points
Less effort and work is required to collect and move many individual items as a single load than to move many items one at a time. Load size and composition may change as material and product moves through stages of manufacturing and the resulting distribution channels.
During manufacturing, smaller unit loads, including as few as one item, yield less inprocess inventory and shorter item throughput times. Smaller unit loads are consistent with manufacturing strategies that embrace operating objectives such as flexibility, continuous flow and just-in-time delivery.
Large unit loads are common both pre and post manufacturing in the form of raw materials and finished goods.
UNIT LOAD PRINCIPLE Key Points
Unit loads composed of a mix of different items are consistent with just-in-time and/or customized supply strategies so long as item selectivity is not compromised.
SPACE UTILIZATION
Effective and efficient use must be made of all available space.
SPACE UTILIZATION SPACE UTILIZATION
Definition: Space in material handling is three dimensional and therefore is counted as cubic space.
Key Points In work areas, cluttered and unorganized spaces and blocked aisles should be eliminated. In storage areas, the objective of maximizing storage density must be balanced against accessibility and selectivity. When transporting loads within a facility the use of overhead space should be considered as an option.
SYSTEM PRINCIPLE
Material movement and storage activities should be fully integrated to form a coordinated, operational system which spans receiving, inspection, storage, production, assembly, packaging, unitizing, order selection, shipping, transportation and the handling of returns.
SYSTEM PRINCIPLE
Definition: A system is a collection of interacting and/or interdependent entities that form a unified whole.
SYSTEM PRINCIPLE
SYSTEM PRINCIPLE
Key Points
Key Points
Systems integration should encompass the entire supply chain including reverse logistics. It should include suppliers, manufacturers, distributors and customers. Inventory levels should be minimized at all stages of production and distribution while respecting considerations of process variability and customer service.
Information flow and physical material flow should be integrated and treated as concurrent activities. Methods should be provided for easily identifying materials and products, for determining their location and status within facilities and within the supply chain and for controlling their movement.
SYSTEM PRINCIPLE Key Points
AUTOMATION PRINCIPLE
Customer requirements and expectations regarding quantity, quality, and on-time delivery should be met without exception.
Material handling operations should be mechanized and/or automated where feasible to improve operational efficiency, increase responsiveness, improve consistency and predictability, decrease operating costs and to eliminate repetitive or potentially unsafe manual labor.
AUTOMATION PRINCIPLE AUTOMATION PRINCIPLE
Definition: Automation is a technology concerned with the application of electromechanical devices, electronics and computer-based systems to operate and control production and service activities. It suggests the linking of multiple mechanical operations to create a system that can be controlled by programmed instructions.
Key Points Pre-existing processes and methods should be simplified and/or re-engineered before any efforts at installing mechanized or automated systems. Computerized material handling systems should be considered where appropriate for effective integration of material flow and information management.
AUTOMATION PRINCIPLE Key Points All items expected to be handled automatically must have features that accommodate mechanized and automated handling. Treat all interface issues as critical to successful automation, including equipment to equipment, equipment to load, equipment to operator, and control communications.
ENVIRONMENTAL PRINCIPLE
Environmental impact and energy consumption should be considered as criteria when designing or selecting alternative equipment and material handling systems.
ENVIRONMENTAL PRINCIPLE ENVIRONMENTAL PRINCIPLE
Definition: Environmental consciousness stems from a desire not to waste natural resources and to predict and eliminate the possible negative effects of our daily actions on the environment.
Key Points Containers, pallets and other products used to form and protect unit loads should be designed for reusability when possible and/or biodegradability as appropriate. Systems design should accommodate the handling of spent dunnage, empty containers and other by-products of material handling.
ENVIRONMENTAL PRINCIPLE Key Points
LIFE CYCLE COST PRINCIPLE
Materials specified as hazardous have special needs with regard to spill protection, combustibility and other risks.
A thorough economic analysis should account for the entire life cycle of all material handling equipment and resulting systems.
LIFE CYCLE PRINCIPLE LIFE CYCLE COST PRINCIPLE
Definition: Life cycle costs include all cash flows that will occur between the time the first dollar is spent to plan or procure a new piece of equipment, or to put in place a new method, until that method and/or equipment is totally replaced.
Key Points Life cycle costs include capital investment, installation, setup and equipment programming, training, system testing and acceptance, operating (labor, utilities, etc.), maintenance and repair, reuse value, and ultimate disposal. A plan for preventive and predictive maintenance should be prepared for the equipment, and the estimated cost of maintenance and spare parts should be included in the economic analysis.
LIFE CYCLE PRINCIPLE Key Points A long-range plan for replacement of the equipment when it becomes obsolete should be prepared. Although measurable cost is a primary factor, it is certainly not the only factor in selecting among alternatives. Other factors of a strategic nature to the organization and which form the basis for competition in the market place should be considered and quantified whenever possible.
Slewing Mechanism The slewing drive is a gearbox that can safely hold radial and axial loads, as well as transmit a torque for rotating. The rotation can be in a single axis, or in multiple axes together. Slewing drives are made by manufacturing gearing, bearings, seals, housing, motor and other auxiliary components and assembling them into a finished gearbox.
The slewing drive is a modernized take on the worm drive mechanism that dates back many centuries and was widely used during the Renaissance Era. Pappus of Alexandria(3rd century AD), a Greek mathematician is credited for an early version of the endless screw, which would later evolve into the worm drive.This mechanism was also used by Leonardo da Vinci as a component in many of his designs for machines. It can also be found in the notebooks of Francesco di Giorgio of Siena. Many slewing drive concepts found prominence with the emergence of larger scale construction and engineering in the height of the Greek and Roman Empires.
Slewing drives function with standard worm technology, in which the worm on the horizontal shaft acts as the driver for the gear. The rotation of the horizontal screw turns a gear about an axis perpendicular to the screw axis. This combination reduces the speed of the driven member and also multiplies its torque; increasing it proportionally as the speed decreases. The speed ratio of shafts depends upon the relation of the number of threads on the worm to the number of teeth in the worm wheel or gear.
As technology has improved, more and more slewing drives are now functioning with hourglass worm technology which functions much in the same way as a traditional worm with one big exception: a traditional worm touches just one tooth at a time while an hourglass engages up to 11 teeth at one time. This increased tooth engagement results in far greater strength, efficiency and durability.
Performance characteristics 1
Because of their multiple uses, slewing drives come in a variety of model sizes, performance ranges and mounting characteristics. The drives are perfect for applications that require both load holding and rotational torque from the same gear box. They can also be made with dual axes of rotation, (turning axes at the same time) or with dual drives on the same axis, (two worm threads driving the same ring gear in one axis)
Slewing drives Slewing and swivelling drives are coaxial planetary gearboxes with two to four planetary stages, which drive large diameter bearings or gear rings via an output pinion. Both swivelling and slewing drives are made with short or long output shafts, depending on the installation situation. The one-piece, case hardened and ground output shaft withstands the highest loads and, if required, can be fitted with profile-corrected gearing. The optimum circumferential backlash is easily adjusted through the gearbox's optional eccentricity. Slewing drives are employed in the slewing mechanisms of construction and mobile cranes as well as ship and offshore cranes. They are also used in rotor blade and yaw adjustment in wind turbines. Slewing gearboxes can be driven either electrically or hydraulically and are available in high gear ratios. If the installation space is restricted, a bevel gear can serve as an entry stage for a slewing drive. The installation position is variable, and can be vertical, horizontal or upside down. For extended operation times, for example when slewing drives power gear ring rope winches, external oil coolers can be provided. 2
Applications There are many applications in which the slewing drive can be utilized, primarily because it is perfect for applications that require both load-holding power and rotational torque strength.
Typical slewing drive applications include but are not limited to:
Solar Trackers Wind Turbines Man Lifts Hydraulic Machinery Telescopic Handlers Digger Derricks Lifts Cranes 3
Drilling equipment Military Equipment
This invention relates to a slewing mechanism and in particular to a mechanism which can effect slewing of a motor vehicle seat so that it effectively moves forward whilst it rotates so that a passenger in the seat can be moved from a position in which the seat is normally located to a position where the seat presents at or beyond the door sill whilst, at the same time, avoiding fouling of a door, door pillar or the like. Whilst we will exemplify the invention by reference to a car seat it is to be understood that the same mechanism is equally applicable to other applications such as in furniture, appliances, agricultural machinery and earth moving machinery. The invention could also be applied to mechanisms in ambulances and for access by the physically disabled to baths or the like and these and other applications are incorporated in the invention. There have previously been proposed mechanisms to enable a person in a vehicle, whether the driver or passenger, to obtain ingress and egress notwithstanding the fact that the person concerned has physical disabilities. In the end result in these previous devices the seat is moveable from a position where it is conventionally located to a position where at least the leading edge of the seat extends beyond the door sill of the vehicle. The previously proposed mechanisms are basically relatively cumbersome and awkward to use and normally necessitate the movement on slides, in two directions. These constructions tend, to be fragile as they often leave the seat cantilevered on the slides. They can also be very complex and expensive. It is the object of the present invention to provide a slewing mechanism which operates effectively to provide both a translation and a rotating movement which mechanism is rugged in construction but nevertheless economic to produce, and, in particular, to provide such a mechanism for use with a vehicle seat or the like. The invention in its broadest concept comprises a slewing mechanism having a primary arm rotatable about a pivot adjacent one end, a secondary arm pivotally connected to the primary arm at a pivot adjacent the other end of the primary arm and an upper plate which rotates about a pivot connected to the secondary arm at a position spaced from its first pivot and means to link the secondary arm 4
to the surface to which the primary arm is pivoted and a second link which connects the upper plate to the primary arm whereby on rotational movement of the primary arm, the upper plate is caused to translate and to rotate. In one preferred form of the invention the translation follows a circular path of constant radius and the rotation over the required movement is effectively 90 degrees. The range of translation and the degree of rotation can be varied within certain limits. The invention also includes a vehicle seat comprising the slewing mechanism of the invention, the seat being moveable between a first position at which it is in the normal position of a seat in a vehicle to a second position where at least its leading edge extends beyond the vehicle door with the seat effectively being directed outwardly relative to the door. In order that the invention may be more readily understood we shall describe, in relation to the accompanying drawings, one particular embodiment of the invention together with certain modifications that can be made to this embodiment. The mechanism has a bottom plate 3 which, in the preferred embodiment may be adapted to be connected by way of a sub frame 102 to the floor of a vehicle and can be of a form to provide the required height. The sub frame 102 may be connected by bolting or otherwise connected to the vehicle body. By using the sub frame 102, the mechanism can be used with a wide range of vehicles. As illustrated the plate 3 may be a square or rectangular plate. Mounted on a pivot 2 connected to plate 3 there is a primary arm 1 and this may be made of any required material and be of any shape. As illustrated it is somewhat of a dumbbell shape and this may be preferred if, say, a bearing race is to be connected between the plate 3 and the arm 1. As illustrated the plate 3 has an arcuate groove 32 and the arm 1 a corresponding groove 11 and ball bearings 12 are located between the two grooves to support the arm relative to the plate and to permit rotation thereof.
5
We also provide a recess 15 in the upper portion of the arm 1 and in this recess there are provided ball bearings for a ball race 14 which co-operations with a bearing member 13 which extends upwardly on a shaft 16 from bottom plate 3. It will be seen that with an arrangement such as this, the arm 1 can rotate readily relative to plate 3 notwithstanding that there are substantial cantilever loads between the contacting faces of the plate 3 and the arm 1. A secondary arm 4 is pivotally connected by means of a pivot 5 which may be attached to arm 1 at a distance from pivot 2 thereof. An upper plate 6 is pivotally connected by means of pivot 7 to the secondary arm 4 with the pivots 5 and 7 being spaced by required distances. The interconnection of the secondary arm 4 with the arm 1 and that of the upper plate 6 with the secondary arm 4, are, as illustrated, similar to the manner of connection of the bottom plate 3 with the arm 1. That is there are annular grooves in the inner faces of the adjoining members which receive ball bearings to permit ready rotation whilst loaded and the pivots 5 and 7 also include ball bearings or ball races to absorb cantilever loads on the members relative to the member therebelow. In fact the connection of the secondary arm 4 and the upper plate 6 is effected in a direction opposite the two earlier connections but the load can be borne in either orientation. Whilst we have described one particular form of bearing arrangements between the adjacent rotating components it is to be understood that these can be varied as required. A primary link 8 is pivotally connected both to the bottom plate 3, by pivot 81 and the secondary arm 4, at pivot 82 and the upper plate 6 is pivotally connected to the primary arm 1 by means of secondary link 9, the connection to upper plate 6 being at pivot 91 and the primary arm 1 at pivot 92. The arrangement of the arms and their links are such that when the primary arm 1 is rotated relative to the bottom plate 3 then the secondary arm 4 is caused to rotate about pivot 5, because of the location of primary link 8, and the pivot point 7 will commence to translate relative to the bottom plate 3. At the same time that this translation is effected the upper plate 6 will also be rotated as secondary link 9 constrains the outward movement of the upper plate 6. 6
The particular arrangement, as illustrated, is effectively symmetrical and the translation of pivot 7 will follow a circular path of constant radius and the rotation of the upper plate 6 can be such that during the movement of the lower plate 1 the upper plate rotates through approximately 90 degrees. This arrangement is satisfactory for causing a seat assembly 100, which is connected to upper plate 6, to move forwardly and outwardly from its initial position to a position in a car door and, at the same time the seat is caused to rotate through approximately 90 degrees so that a passenger in the seat will move from a first, normal, position directed towards the direction of movement of the vehicle to a second position substantially at right angles thereto. The movement is such that during the initial part of the movement the seat will move forwardly past the door pillar 101 and then rotate outwardly so that at least part of the seat extends through the door opening. On the reverse movement the seat will move inwardly and then rearwardly effectively around the pillar 101 until it assumes its initial condition. Figures 4 and 5 show an arrangement in which the mechanism is associates with a car seat and this will be described further hereinafter. It will be appreciated that such a seat is most desirable for persons with disabilities who can, say, be removed from a wheel chair and placed on the seat when it is in the second position described and then the seat can be caused to move to a normal driving or passengers position. Depending upon the particular configuration and movement required the lengths of the various components and linkages and the location of the pivots, can be changed to give a combined movement which differs substantially from that illustrated above. The movement may be elliptical rather than circular and the translation and rotation components of the movement can vary widely. Such movements may be required for particular applications. For example if the door pillar is located forwardly of the seat, it may be necessary for the seat to move forward substantially before it starts to move on the arc of a circle and before the rotation is effected. Movement of the mechanism can, it will be appreciated, be effected by movement of any of the components but normally would be effected either by positive movement of the primary arm 1 or movement of the upper plate 6. For example when the mechanism is applied to a vehicle seat the movement may be 7
achieved by physically moving the seat and its occupant after some form of latching mechanism is released. Figures 4 and 5, which show the car seat assembly 100 associated with the mechanism also shows a driven form of mechanism and a form of locking mechanism. In this form the plate 3 is connected to one side of a sub-frame 102 which, in turn, can be connected by bolts or the like 103 to the floor pan of the vehicle, the frame 102 affectively occupying the same position as the conventional seat rail assembly. The seat rails 104 are then connected to the upper plate 6, by means of any required sub assembly 105 which may be necessary to permit the required connection and the seat 105 is mounted on the rails in a conventional manner so as to be adjustable there along. By providing different sub-assemblies 105 so different forms of seat can be connected to the same mechanism. The mechanism can be sufficiently thin that, notwithstanding the mechanism and the sub-assemblies 102 and 105, the normal vehicle seat can be used and can be at its normal height. In order to lock the assembly we provide a locking pin 110 which is biased by a spring 111 to normally extend outwardly, as shown in Figures 4 and 5 and to the inner end 112 of the pin there can be connected a flexible cable or the like 113. This cable may terminate on the side of the seat in a position which is exposed when the seat is in its normal, driving, position and a handle or the like 114 can be provided to cause movement of the cable 113 and thus of the pin 110. On the seat assembly 100 there can be an aperture or the like through which the pin can pass so that when the seat assumes its normal position then it is prevented from further movement until the pin 110 is released. When the seat reaches this position we can provide additional inter-engaging lugs, normally two such lugs which provide force transfer if the vehicle is in an accident situation. The pin 110 may have a tapered outer end or the seat frame may have a ramp so that the locking movement is automatic when the seat reaching its normal position. Associated with the locking pin there is a second locking member 120 which is connected at one end 127 to the end 112 of the pin which member is itself adapted to be rotatable about a pivot 121. 8
The free end of this member, which is unturned, is formed to mesh with teeth 124 on an arcuate member 123 which is connected to the primary arm 1. The connection is shown as being by nuts or studs 125, 126. The arcuate member is arcuate about the axis of the pivot 2 of the member 1. The arrangement is such that when the seat is in its normal position and the handle 114 is operated the pin 110 is drawn inwardly against the spring 111 and the lower end of the member 120 is caused to rotate in a clockwise manner, looking from the direction of Figure 5 about its pivot 121 and this causes the formed end 122 to disengage from the ratchet teeth 124 on the arcuate member 125. If at any stage during rotation it is required to lock the seat it is only necessary to release the handle 114 and, under influence of the spring 111 the member 120 will rotate about pivot 121 and its end 122 will engage the teeth 124 on the member 123 and the seat is locked. Further manipulation of the handle will again free the seat. That is to say in order to effect rotation of the seat the handle 114 has to be operated to free the mechanism. It is also possible to motor drive the mechanism, although this is not shown but preferably a motor would be used to cause rotation of primary arm 1. This is most convenient as the arm 1 is connected by the pivot 2 to the vehicle body so the only movement of the arm is rotational movement about the pivot. The form of operation and the form of motor used will not be further described except to say that the motor may be electric, hydraulic or pneumatic. The periphery of the arm 1 at the pivot 2 may be formed as a worm wheel or may have gear teeth therein and the motor may be provided with a worm or spur gear to effect driving. Alternatively a linear actuator or screw could be used to effect the movement. In such an arrangement whilst the motor is operating the seat will move but, generally, when the motor stops the seat will be locked in the position then reached. With a motor drive arrangement we may still leave the arcuate member 123 and the member 120 in operation or these could be disregarded. If required, in the motorised version, the-switch for the drive motor may be actuated when the handle 114 is moved to release the pin 110 so that the seat 9
will automatically be moved to its second position when the pin is released and so long as the switch was closed. The handle 114 could then be associated with a further switch which would be operated on reverse movement thereof to cause the motor to drive in a reverse manner to move the seat back to its normal position. If a motor driven version is provided then we prefer to provide limit switches at the two ends of its movement so that the motor is de-energised when the seat has reached the limit of its movement in a particular direction. In other applications we may prefer to provide mechanical stops which prevent extreme movement of the seat. Whilst we have described the seat as being in the passenger's position it will be appreciated that a mirror image of the mechanism will work equally satisfactorily for a driver so that a disabled driver may use the seat incorporating the mechanism of the invention equally as satisfactorily as a passenger. Also, and as mentioned earlier herein whilst we have described the mechanism specifically for use in a car seat to enable disabled persons to readily enter and leave a motor vehicle a similar mechanism could be used in other applications where a mixture of translation and rotation is required. For example in some heavy agricultural and civil engineering equipment the space for a driver is very limited and it could be desirable to use a mechanism of the type described herein in association with a seat in a vehicle of that type to facilitate ingress and egress of the driver.
FOUR POINT CONTACT SLEWING BEARING LUBRICATION & MAINTENANCE
Slewing is defined as the rotation of an object about an axis. Thus a slewing ring bearing is a bearing used in slewing applications for transferring/supporting axial, radial, and moment loads, singularly or in combination, consisting of rings mounted with threaded fasteners, and usually having a gear integral with one of the rings. Slewing ring bearings with integral gears are purchased by some water and wastewater equipment manufacturers without the capability of manufacturing drives in house. These slewing rings are then assembled along with other components into a clarifier drive. Thus component drive assemblers 10
are those that buy components designed and fabricated by others and assemble these pieces into drives. Drive manufacturers design and fabricate their own drives. The assemblers of component drive frequently claim ease of maintenance and reduced lubrication requirements as a benefit of these assembled slewing ring clarifier drives. Component drive assemblers minimize the required maintenance for these drives contrary to the slewing ring bearing manufacturers’ recommended lubrication and maintenance procedures. In fact, many drive assemblers are unaware of or have actually ignored the slewing ring bearing manufacturers’ recommendations concerning lubricants, frequency of re-lubrication, as well as types and frequency of maintenance inspections and services. For example, in outdoor, humid, dirty, or dusty applications, and for 24 hour continuous operation as found in clarifier applications; slewing ring manufacturers recommend the re-lubrication of grease lubricated slewing ring bearing as often as every eight (8) hours. The failure to include the slewing ring manufacturer’s vital lubrication and maintenance in the component drive assembler’s installation, operation, and maintenance instructions can result in the premature failure of the bearing, the gear, or both. An example of this deficiency is the absence of slewing ring mounting bolt annual inspection and re-tightening requirements. Loose mounting bolts leads to gear mesh misalignment and unusual loading of the bearing, which can result in a drive failure. Such unscheduled outages consume precious maintenance time, resources and funding that would otherwise not be required and thus available for scheduled maintenance or other functions. All of the slewing ring bearings produced by the manufacturers presented here are excellent bearings. The component drive assemblers’ application or misapplication of these bearings and the absence of the slewing bearing manufacturers’ maintenance recommendations in drive assembler’s installation, operation, and maintenance procedures, in short a failure to present the slewing ring bearing manufacturers’ lubrication and maintenance recommendations to the end user is the true failure here.
11
12
Pneumatic conveyor
It Can be used for both bulk and unit movement of materials Air pressure is used to convey materials through a system of vertical and horizontal tubes Material is completely enclosed and it is easy to implement turns and vertical moves 12(a) Dilute-phase pneumatic conveyor Moves a mixture of air and solid Push (positive pressure) systems push material from one entry point to several discharge points Pull (negative pressure or vacuum) systems move material from several entry points to one discharge point Push-pull systems are combinations with multiple entry and discharge points 12(b) Carrier-system pneumatic conveyor Carriers are used to transport items or paperwork Examples: transporting money to/from drive-in stalls at banks and documents between floors of a skyscraper
1
Pneumatic conveyor systems Every pneumatic system, would makes use of pipes or ducts called transportation lines that carry mixture of materials and a stream of air. These materials are such as dry pulverized or free flowing or light powdery materials like cement, fly ash etc. These materials can be transported conveniently to various destinations by means of a stream of high velocity air through pipe lines. Products are moved through various tubes via air pressure , allowing for extra vertical versatility. Pneumatic conveyors are either carrier systems or dilute-phase systems; carrier systems simply push items from one entry point to one exit point, such as the money-exchanging tubes used at a bank drive-through window. Dilute-phase systems use push-pull pressure to guide materials through various entry and/or exit points. It is important to note that either air compressors, vacuums, or blowers can be used to generate the air. This will all depend on what the engineers think will be the most efficient and economical way of developing the system. Three basic systems that are used to generate high velocity air stream: 1. Suction or vacuum systems, utilizing a vacuum created in the pipeline to draw the material with the surrounding air .The system operated at a low pressure, which is practically 0.4–0.5 atm below atmosphere, and is utilized mainly in conveying light free flowing materials. 2. Pressure-type systems, in which a positive pressure is used to push material from one point to the next. The system is ideal for conveying material from one loading point to a number of unloading points. It operates at a pressure of 6 atm and upwards.
2
3. Combination systems, in which a suction system is used to convey material from a number of loading points and a pressure system is employed to deliver it to a number of unloading points.
A pneumatic conveying system transfers powders, granules, and other dry bulk materials through an enclosed pipeline. The motive force for this transfer comes from a combination of pressure differential and the flowof a gas, such as air or nitrogen. (For simplicity, we’ll call the gas “air” in this article.) The system’s basic elements include A motive air source (also called an air mover, such as a fan or blower), a feeder or similar material-introduction device, a conveying line, a termination vessel (such as an air material receiver ), and a dust collection system. While some of the most common materials transferred by pneumatic conveying systems are flour, cement, sand, and plastic pellets, any of hundreds of chemicals, food products, and minerals can be pneumatically conveyed. These materials are usually fairly dry materials in slurry or paste form typically aren’t suited to pneumatic conveying. Working of pneumatic conveyer Doing work requires energy. To turn a bolt, for instance, you need to provide energy in the form of torque. Such mechanical torque is usually expressed in foot-pounds, and both elements—feet and pounds—are needed to do the work .Energy is also required to move material through a pneumatic conveying system, but in this case the energy is supplied by pressure differential (in pounds per square inch) and airflow(in cubic feet per minute). In a pneumatic conveying system, the air pressure in the conveying line is changed by the system’s air mover ,which generates pressure or vacuum. Where the air mover is located in the system determines whether it generates one or the other: When located at the system’s start, the air mover pushes air through the system and the system operates under pressure. When located at the system’s end, the air mover pulls air through the system and the system runs under vacuum. By controlling the pressure or vacuum and airflow inside the system, the system can successfully transfer materials. Advantages of pneumatic conveyer Let’s start by looking at mechanical conveying systems. A conventional mechanical conveying system runs in a straight line, with minimal directional changes, and each directional change typically requires its own motor and drive. The mechanical conveying system may be open rather than enclosed, potentially generating dust. It also 3
has a relatively large number of moving parts ,which usually require frequent maintenance. The system also tends to take up a lot of valuable real estate in a plant.
Disadvantages of a pneumatic conveyer A pneumatic conveying system typically requires far more horsepower to operate than an equivalently sized mechanical conveying system. The reason is that changing the air pressure to achieve pneumatic conveying consumes a large amount of power and is inherently less efficient than a mechanical conveying system’s mechanical transfer. In fact, in applications with the same transfer rate over the same conveying distance, a pneumatic conveying system can require 10times the horse power of a mechanical conveying system. A pneumatic conveying system also requires a larger dust Collection system than a mechanical conveying system. This is because the pneumatic system has to separate the conveyed material from the conveying air at the system’s end. Some materials have characteristics that make them difficult to convey in a pneumatic system. Examples are a material with a large particle size and high bulk density, such as gravel or rocks, and an extremely sticky material, such as titanium dioxide, which tends to build a coating on any materialcontact surface. In a pneumatic conveying system, such buildup often leads to total pipeline blockage. These difficult materials can be easier to transfer in a mechanical conveying system that’s been carefully chosen to handle them Types of pneumatic conveying systems? Pneumatic conveying systems are classified by their operating principle into two types: dilute phase and dense phase. Either can run under pressure or vacuum. Dilute phase. Dilute-phase (also called stream-flow) pneumatic conveying is best compared to what happens in a parking lot on a blustery day .While walking to your car after work ,you’re blasted with dust and dirt that’s been picked up off the ground by fast-moving wind. The faster the wind, the more material hits you. As the wind speed picks up, larger dirt particles also become entrained in the wind. Picture the debris carried by a tornado or hurricane: These storms are pneumatically transferring enormous “particles” in dilute phase. Just like the wind picks up the dust, the dilute-phase conveying system relies on the airstream’s velocity to pick up and entrain each particle ,keeping the particles in suspension throughout the conveying line. A typical dilute-phase pneumatic conveying system is shown in Figure 1.The pickup velocity at the system’s start 4
(that is, the airstream velocity at which material is picked up and entrained at the material feed point ) is generally considered the system’s most critical area, because the air is at A simple way to think of a dilute-phase conveying system is that it operates at a relatively high velocity at a relatively low pressure differential. A simple way to think of a dilute-phase conveying system is that it operates at a relatively high velocity at a relatively low pressure differential. To design a dilute-phase pneumatic conveying system with the air volume to convey your material, you must use mass calculations (that is, pounds of material per pound of air) while considering your installation location’s ambient air temperature, humidity, and altitude. Then to achieve the proper mixture of air and material in the system, you must meter the material into it at a controlled rate. Dense phase. Dense-phase pneumatic conveying is also best described with an analogy: It’s similar to what happens in making sausage, when you use high pressure to force ground meat into a casing. An ideal dense-phase conveying system would extrude material with enough pressure to transfer it in one long, continuous piece through the pipeline’s entire length, just like a continuous length of ground meat inside a sausage casing. But with dry bulkmaterials like powders and granules, this usually isn’t possible because of the material’s high frictional resistance against the conveying line’s inside wall. Instead, air and material flows through the line in any of several patterns (including various forms of two-phase flow and slug flow). While various dense-phase conveying system types are available, all use a relatively high pressure differential with a relatively low air velocity. The most common dense-phase system type, as shown in Figure 2, provides batch transfer using a transporter (also called a blow tank or pressure tank). In this system ,material from a storage vessel is loaded by gravity into the transporter. After the transporter is full, its material inlet valve and vent valve are closed and compressed air is metered into the transporter. The compressed air extrudes the material from the transporter into the conveying line and to the destination. Once the transporter and conveying line are empty, the compressed air is turned off and the transporter is reloaded. This cycle continues until all the material required for the process has been transferred. Shown in detail in Figure 3, an air injector works by injecting compressed air (or another gas, such as nitrogen, to match the conveying gas) into the conveying line. The added air can clear any plugs caused by low air volume or pressure, eliminating the chore of dismantling the line to remove plugs. Using the 5
injectors reduces the system’s air volume safety factor by reducing the air volume required for reliably conveying the material. (An air volume safety factor is typically built into a pneumatic conveying system’s design to ensure that the system has slightly more air volume than the application requires; however, while this extra air volume helps the system reliably convey material without plugging, it also increases the system’s energy consumption.) Air injectors along the conveying line can also be used to gently restart flow when material is left in the line after the conveying cycle. This is a particular advantage for a system handling an abrasive or friable material or a material blend. When the system is restarted without supplementary air, the higher-speed material flow can cause an abrasive material to produce excessive and premature wear on the conveying line and other material-contact components. This higher-speed flow can also damage a friable material, resulting in unacceptably high amounts of particle attrition. It can also de blend a mixture of materials with different particle sizes and bulk densities. Using supplementary air in the line can not only prevent wear, attrition, and de blending problems when a power outage or other event abruptly shuts down the conveying system when it’s full of material, but can provide more system design flexibility for an application where you want to intentionally leave material in the line between cycles. Air injectors must be designed as fail-safe check valves to prevent the conveyed material from intruding into the injectors’ compressed-air supply. Such intrusion can occur when material slugs (also called pistons) form inside the dense-phase conveying line (Figure 2); because of the slugs’ changing velocity in the line, usually before line bends, the air in the pockets between the slugs can become pressurized to a level higher than that of the compressed air injected into the line. If this overpressure condition occurs at an air-injection point and the air injector doesn’t have a check valve, some particles can enter the compressedair supply. pneumatic conveying system is operating in dilute phase or dense phase Unfortunately, there’s no industry standard for measuring these operating phases. So just because a pneumatic conveying system has a rotary airlock valve, it’s not necessarily operating in dilute phase, and just because a system has a transporter, it’s not necessarily operating in dense phase. However, you can use these rules of thumb for determining a pneumatic conveying system’s operating phase: •Most dilute-phase pressure systems operate below15 psi 6
(typically between 4 and 8 psi), while most dense-phase pressure systems run above 15 psi. •Most dilute-phase vacuum systems operate below 12 Inches mercury (typically between 8 and 12 inches mercury), while most dense-phase vacuum systems run above 12 inches mercury (typically between 12 and 14 inches mercury). •Depending on the conveyed material ,most pressure and vacuum dilute-phase systems have an air velocity between 3,500 and 9,000 fpm and most pressure and vacuum densephase systems have a 3,000-fpmor lower air velocity. • In a dilute-phase system, the material velocity is nearly the same as the air velocity. In a dense-phase system, especially one with slug flow, the average material velocity is much slower than the air velocity. In either system, the material can’t move faster than the air. One caution: When you’re talking to a dense-phase system supplier about selecting a new system, make sure that the material velocity numbers the supplier is using are clearly defined. Some suppliers use air velocity and material velocity numbers interchangeably. Make sure you know what numbers the supplier is talking about before you accept the supplier’s material velocity claims. 4. Figure 3 Selection of pneumatic conveying system for application Major factors to consider. The first thing to address when selecting a dilute- or dense-phase pneumatic conveying system is your material’s characteristics .These include the material’s particle size and shape, bulk density, moisture content, abrasiveness, friability, cohesiveness, hygroscopicity, static charge, explosivity , toxicity, melt point, and many others. Next, consider how the system will fit into your location and plant environment .How will the system’s planned line routing and length fit into your installation area Are there any physical constraints in the area, such as other equipment or spots with low headroom What will it take to fit the system into your available area within these constraints? And how can the system be configured to provide Easy maintenance access to system components? Another major factor to consider is what material transfer rate the system must achieve to meet your application requirements. Making a choice. Assuming that your material can be pneumatically conveyed (that is, it doesn’t have a large particle size and high bulk density and it isn’t extremely sticky), and without considering any other factors at this 7
point, start by considering the conveying system with the lowest initial investment cost: dilute phase. Whether the dilute-phase system should operate under pressure or vacuum in your application depends on two main factors: •Whether air leaking into or out of the system will have a negative effect: For instance, air leaking out of a pressure system that conveys a toxic or explosive material can create hazardous conditions in your plant. In this case, a vacuum system would be a safer choice. •Whether your material packs tightly (like wood shavings), is cohesive and tends to build up on surfaces (like titanium dioxide), or is fibrous (like some grain hulls): For materials like these, a vacuum system may be the better choice. This is because the vacuum in the conveying line tends to pull the particles apart during conveying rather than push them together or into the line walls as pressure conveying does. Some factors may make a dense-phase conveying system better suited to your material. The dilute-phase system relies mainly on providing a high enough air velocity to keep material entrained in the air stream. This relatively high velocity can damage a friable material, resulting in unacceptably high amounts of particle attrition. It can also de blend a mixture of materials with different particle sizes and bulk densities. In both cases, the gentler conveying in a dense phase system—which relies more on a high pressure differential than a high air velocity—is often a better option. The dilute-phase system’s high velocity can also be a problem for handling an abrasive material, which can quickly wear the conveying line and other components, making a dense-phase system the clear choice in this case. Also consider a dense-phase conveying system when your system will include long conveying line runs. A dense phase system typically requires a smaller line diameter than a comparably-sized dilute-phase system. This means that the dense-phase system not only requires less air volume but, in a long system, the smaller-diameter line sections are much lighter, making their installation and replacement easier. The dense-phase system’s smaller and lighter elbows and similar components provide the same advantages. Choosing pressure or vacuum operation for your dense phase conveying system depends on the same factors as for a dilute-phase system: whether air leaking into or out of the system will have a negative effect and whether your material packs tightly, is extremely cohesive and tends to build up on surfaces, or is fibrous. The supplier should conduct the tests with the same material the installed system will handle in your plant 8
and simulate your field conditions as closely as possible . Once you’ve decided on a dilute- or dense-phase pneumatic conveying system and determined whether it will operate under pressure or vacuum, have the system supplier run pilot-plant tests of the proposed system in the supplier’s test facility. The supplier should conduct the tests with the same material the installed system will handle in your plant and simulate your field conditions as closely as possible. This includes configuring the pilot plant system, if possible, with the same conveying line routing, length, and number of bends that the installed system will have and running the tests under your plant’s ambient air temperature and humidity conditions. Before the supplier runs the tests, you should define several test criteria. Basic criteria include whether the proposed system conveys your material, at what rate it conveys the Copyright, CSC Publishing, Powder and Bulk Engineering material, and how much air the system consumes. You also need to define criteria specific to your application. If, for instance, you’re conveying a friable material and are concerned about material attrition, you need to define how much attrition is acceptable and then accurately verify how much attrition occurs during the tests. The supplier will use the pilot-plant test results to size the conveying system that’s installed in your plant .Make sure that you understand exactly how the supplier will use the test results to size your installed system and, in particular, how the supplier will use the data to calculate the installed system’s material conveying rate and air consumption.
9
01 23 56789 9 69 !"#$$!"% 96&% ' 7%(7 & 6
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`a_`a_bTc_`d_`d_TbTe_`d_`d_bTfg_`^_`^_T fg_`c_`^_h A69 @9 8& i9j& 9
9k& lmnolpnoqn %% plnolrnolnn %% pqnoplnolrn %%B
56&& @9
s
stuvwxuyzw{|v}swv|zs~usvsws}uuv|
sszu|vszs|vsz~|{stuvwxuyzw{|v}s{ys ~szu|vszs|vsu{suu|us|vsu{|ws~usuvs|
swu{suvs{yzuv}wu{szs |vsu{s~u|v}s~svsz~|{swz{sw{xuysx{s{{svz|uz|vsw{s|vs{wyssws u{sytzsy{ssz~uzsz~syuvvzswzsz~sw{{wv|v}susz~su{s~|}~sws|vs ~ws~zs~|zusuvs|vstuvwxuyzw{|v}s|vwz{|suvwxuyzw{sswz||
|v}suzzs zy~v}sz~s~usyvzsx|v|~|v}suvsu{syuusxs{v{|v}su{s ; !
30 !"$#00$ # 0$. ,7!0 $)/ $)$ $)0 ! )0 0 #$ #$*+ 36:/ ; 0; 70< $,20$ N + $ $ # 0 ! 70
01234157899408 9940 4254548 52 001234521420471 4592 89 5892 47 1389592 08 94 202 0145514 759 140 08 7 10877414 958 45 2142 989294182 2 459 148 252 52498 8 8 94548 5382 4 59240 4 41942 4389 92 4 9125 19 252 42 0
28 94 2 4 598 40 !!! ! ! ! !
"#$%&'(!)'*%!
+
4142142 2 8298 57 1 1 25988 542 45409 4 2 494 59 1247429145 7 154 8 9 542129452 8945, 158 549425 592 02 459 1244548 521420458 5418 12 89 7 259828 94 5918 2 0012 4454 25988 5214459589407 159 124 7 214 45 4542142147 0458 408 218 558 45,52452 02289254194 845 7
1 84 95
-./012340156/78492:04/6844 ;<35=92:/125:45>401/3?4/:@4A/:740156/78492:44 B
F%G%
HI2 59240 42 941389592 8 52 02 5 540389 41402 4 ,128 ,2 021959 7 12 477884 9 5594, 988 459 124524 J4252 0 8 K 892 47 1 218 5 24 LM24 13 1 24 42 2 0 421 1041 NO12 4,84 8,
P9 82 0 4 84 98
01 23567
9 7 2 1 512356
2 377 !"# $ $% &'( )#6 * 22 + 6,51 - 7 6**67 -5123.1 7 6 6 /012 01235 - 73 - 1 -655 6 152 22 6*2 22/4 75 1 51235 /63 6755- 36 6362 789:;<9=>>?@;A=B>8CB?D6 -2 * 7 5 3E * 5 F 6362 G 7 2- 6 22 /6 67 2
1 267 7567- 37 3 63 1 7 2512 67 /H75 2 1 -5123* 3 67 I5 3 - 2136713 7 2 33767 5671 5/ J1 52*2 6 F32 1 *2 6 G 1 - 3*1 72 6 6 67 / K 3*1 677*2 6 267 5675 1 * 7 7 /L 26775 6 67 2 2 3 63 1 -26.16 /4 51235 5 2 52 17 52 1 52/L3 52 -5 -2F37 37G 3 * - 6 17 6*37 /
M
01235 1 -2 * 36 3 22 7 67 712 3 6 2 * 26.16 /M 67671 56 337I 6**67 7 -512367 36 3 6 2 *6 -1 * 67 * 3 67 /65 3 63 1 22 7 6*3 6 2 - 5 267 7 /H71 6* , 1 7 1 5
7 1 67 71 6 25 12 /
012
56789 1 9 7 1 97 1297111
8 98 7 7 99 7 !1 16 9 67 96 7 7 9 87 1 7 9676 79 1 97"1 1 71 9 ! 71 761 96 1 6 16 76 0127 9! 7971 9 879 7 98 #9 111 7 98"1 1 1 9 7 7 19 "97 19 "1 1 #7 616$ 9 879 7 98 %#7 &79!9 ! 17 ! 9887" 99 # 12 1 #7 &71989 798 96 75 1 9 7 12 97 ! 116 # 6 16 9 67 '#7661 7 #97 7 7"9 121 7 9689 1
$ 7 16 #988 7 89 9! 7 727 7" 9 129!#9 79#1 &16 98 1
7 16 #9 (9 7"78169 7" 161 198)
8171 17 1 9 7 "1 616$7 98 7 57 1 9 71 1 97 129! 71767 ! 9 6"88 6" 8 61 71 6 #78 "# #9!
7# 6796*1 9 767 !9 9 #" 89 "1 81 +
, -.9 +9 6 12 , /0 1 97 127
.9 +9 6 12
01213457891 1 431 19444 7 341
33471 4 99 741341 33471 13 431 1431 7 58 17 734 9 374 431 193 7 3 73 7 443134714 3 7 71 7317 71471345 37149478 71 1 5437 171 45514 4 3471 3 94913 43194913 43 9371 11
438 174 317 34 541 1431734 9 3714 7 31 547 41317147719 7 551 1431 17 94414 1341 711 1713 3 171 31 1454 51 1 34 4 7 341 371314 24347 71 5437 71 7 1 3 3748 3!3 74 7 4 71 349911 34721 349994913"7 7891 4558 5713 737 744
543 #194913 43 147 39444 73 7 $ 179$ 3394913 43 41 7 1394913 43 9134175851 7 1713 794913 7474 19371 3 5 31%51 5437 71 1431 4
1 5147719 7 4 47314734 9 371453148$ 179$0179 1 431 31 191 2174 5 1 44317894558 1 393 717245171 4 17 471 3 45513 1315173 3471 4142878 99 7413 3455841 !3471 431 77 3 1 1 45 14 142878 99 7413 & 34 1 74137 1 43471 455 7 1 7 19795417 31 57713471 7317 71 74131
7317 4 1 71 7134 3471 4 1 71 17744338 1 3171 7 9 3 91 74551 24347 71 1 71 1 1 3 13471 34558 1 3
994 7 3191 21 1 7 448 31 34721 393 7 45939 1 34 4 7 341 714 393 717 3 99 5 45431 71 1 7345123 17 '7 #17 7 155 4945517 (191 5 4514 91 41 71713 )*+,-.4/-0431 171 1 713414 58
0123456829
296 23 123 543 2 16 42 16866362341 64 16436 166 2363461 64 261 6 43612 4 6314 241 2 !"#$ %#!& '# (&)#*
+ , 23 4 6 4829 23 123 5 543 41163263 1864 2 48 23861 4163 4 1413614 42634162 1362 5 3216 543 -2.6368296 44 2 4 14 163 5116634136/! & ##0#01 + ,2 1325829223 4 6 4 63623486829 23 123 5262321634486 16 46 1632 13258292 261 6 6 23 4 6 141436225632314868296 81436 146
4.423 223 23 364 6 63 1 + ,122829 6 23433 5122 2 43 2 3 46163 6 4214 63641 23 23148 134163145 1 123456 23 146. 1 56 4 2323 36 236 2363 446 4228296 436 463 1381 364 5 829214 5456436216961612 3216116 32161 16829 631623 66 + 4622 123456829 23122 1361 54 .436431.233 61 4 138294612 86256364 1 548611636 6144 5829233416723 1464829 5186 43 5 4638243829 1642 4233541682983 12864.226829. 14 46 3 464 16362363 1642 43634162 131 2, 123456829423421 4645623 2 14132161162161 16829 6623 4364 4 26 2146 56 416 2323 81 4263 29.22561 1 46 32 1 63 2332631 6 234 413 51 162 829412512 632631 6 436694 6 .643 5462341 6829
;
:
Walking beam conveyors Walking beam conveyance offers the best solution for accurate movement and positioning of packages. A walking beam sweeps backwards and forwards, whereby the packages progress on the basis of the forward sweep. Parts shaped appropriately for the packaging and a servo-controlled drive unit ensure the accuracy of the positioning. A walking beam conveyor system can be used for all packages due to the interchangeability of the shaped parts. Walking beam conveyors can also be converted from a single line to a multiple line version. These features, in combination with a servo drive unit create a conveyor system that can move any package at any speed over any given distance. The walking beam conveyor is in first place on the list of hygienic conveyor concepts for packaging. The conveyor has an open and accessible construction, which makes it simple and easy to clean.
Almac Industrial Systems, the Ontario-based manufacturer of material handling equipment, adds new product to the company's portfolio; a ‘Walking Beam’. Offered as an automated transfer and storage bank with mechanically actuated transfer unit, the Walking Beam is packed with unique features, including the exoskeleton frame, "walking beam" suspension, and a drive train and track system. When engineers think about synchronous automated assembly systems, they most often picture rotary indexing dials or carousels. But, there is another synchronous automation platform that should not be overlooked: the walking beam. A walking beam moves product sequentially in straight-line steps. To advance the product, the beam usually engages them from below, moving up, forward, down and back. In some cases, the beam contacts the products from the side. For speed and accuracy, the motion of the beam is most often generated by a rotating camshaft powered by an electric motor or a roller movement in a profile powered by hydraulic cylinder, explains Robert Austin, senior designer at Almac Industrial Systems, (Aurora, ON). The beam's motion replicates an arm that rises and falls like a seesaw. These machines are based on high performance servo technology and provide a stable & fast transfer system for rigid containers where alternative in-line transfer systems such as rope or chain conveyors are unsuitable. Filling options include high accuracy program forward weight controlled filling, with facilities for vibration at fill points to compact difficult products. The weighing is accomplished by load cells mounted on a fixed structure within the path of the movable carriage of the walking beam conveyor or the load cells are built into the carriage itself.
1
A walking-beam conveyor for the stepped conveyance of drums or similar conveyed stock typically has at least one walking beam that is raised and lowered by lifters between lateral support rails and is movable by at least one longitudinally effective actuator in the longitudinal transport direction. Almac products use Allen Bradley micro logics 1000 compact processor with fixed I/O for controls but can also be customized to incorporate other type of control systems. Preferably, such a walking-beam conveyor has a plurality of walking beams arranged successively in the work piece-travel direction that are moved step-wise downstream and upstream jointly. At the same time, the walking beams are jointly raised while moving downstream and lowered while moving back such that the drums or the like resting on the lateral support rails can be conveyed in steps in the work piece-travel direction. A walking-beam conveyor of this type can be easily integrated as conveying equipment in Mineral processing plants.
2
Industries that use conveyor system •
Conveyors are able to safely transport materials from one level to another, which when done by human labor would be strenuous and expensive.
•
They can be installed almost anywhere, and are much safer than using a forklift or other machine to move materials.
•
They can move loads of all shapes, sizes and weights. Also, many have advanced safety features that help prevent accidents.
•
There are a variety of options available for running conveying systems, including the hydraulic, mechanical and fully automated systems, which are equipped to fit individual needs
•
DESIGN PRODUCT NEWS Walking-beam conveyors allow multiple processes By Murali Shivamuthulingam Almac Industrial Systems, the Ontario-based manufacturer of material handling equipment, adds new product to the company's portfolio; a ‘Walking Beam’. Offered as an automated transfer and storage bank with mechanically actuated transfer unit, the Walking Beam is packed with unique features, including the exoskeleton frame, "walking beam" suspension, and a drive train and track system. When engineers think about synchronous automated assembly systems, they most often picture rotary indexing dials or carousels. But, there is another synchronous automation platform that should not be overlooked: the walking beam. A walking beam moves product sequentially in straight-line steps. To advance the product, the beam usually engages them from below, moving up, forward, down and back. In some cases, the beam contacts the products from the side. The equipment shown is fitted with facilities for vibration at fill points for compacting. For speed and accuracy, the motion of the beam is most often generated by a rotating camshaft powered by an electric motor or a roller movement in a profile powered by hydraulic cylinder, explains Robert Austin, senior designer at Almac Industrial Systems, (Aurora, ON). The beam's motion replicates an arm that rises and falls like a seesaw. These machines are based on high performance servo technology and provide a stable & fast transfer system for rigid containers where alternative in-line transfer systems such as rope or chain conveyors are unsuitable. Filling options include high accuracy program forward weight controlled filling, with facilities for vibration at fill points to compact difficult products.
3
The weighing is accomplished by load cells mounted on a fixed structure within the path of the movable carriage of the walking beam conveyor or the load cells are built into the carriage itself. 2-Vibration stations
A walking-beam conveyor for the stepped conveyance of drums or similar conveyed stock typically has at least one walking beam that is raised and lowered by lifters between lateral support rails and is movable by at least one longitudinally effective actuator in the longitudinal transport direction. Almac products use Allen Bradley micro logics 1000 compact processor with fixed I/O for controls but can also be customized to incorporate other type of control systems. Preferably, such a walking-beam conveyor has a plurality of walking beams arranged successively in the workpiece-travel direction that are moved step-wise downstream and upstream jointly. At the same time, the walking beams are jointly raised while moving downstream and lowered while moving back such that the drums or the like resting on the lateral support rails can be conveyed in steps in the workpiece-travel direction. A walking-beam conveyor of this type can be easily integrated as conveying equipment in Mineral processing plants.
4
Fig 2&3:Specially designed conveyor using both rollers and chain transfer at the exit section of the waking beam shown above.
5
Importance and scope of material handling Material handling in addition to handling of materials in an industry is also significant in terms of costs in overall operations because it is something that is quite common to all manufacturers. But when once its nature is exposed it may be difficult to overlook it as a major potential of effecting cost reduction. Materials handling problems assume importance due to a number of factors. 1. Various studies made in different industries indicate that the cost of handling alone accounts for about 20-25% of total manufacturing costs. What the cost in any particular industry may be is largely the result of the methods and equipment used.2. It is usually found that each part is handled 50-60 times while it passes through the chain of manufacture. Expressed in tons, it is found that on an average 59 tons of material are handled for every ton of finished product. 3. Increased safety — Material handling account for 21% of the permanent disabilities and over 25% of the temporary disabilities. 4. Reduce damage claims — Modern handling methods have paid off in the reduction of damage in parts and materials. 5. Ease drudgery for men — Most of the jobs done by man handling are mere drudgery for men in the first place. Some of the mechanized handling jobs being done today would be a sheer physical impossibility for manual labor within the present economic frame work. 6. The field of materials handling remains still to be fully to be fully explored. Material handling techniques are not only industry’s biggest opportunity — they are industry’s biggest necessity. Competition is beginning to force this new technology upon industry.
Scope of Material handling: Materials handling is spread over to many different industries and fields of engineering, Manufacturing Manufacturing is the largest single field for applications of material handling where a wide range of materials handling equipments are used. Materials handling problems involve surveys, plant and equipment layouts, routing, packaging and storage of materials. Processing Processing requires handling of bulk materials (like gases, liquids, semiliquids and bulk solids). Special handling problems affect the plant design. Construction Construction needs proper receiving, sorting, storing and moving materials. In heavy construction projects, there is now a choice of special methods and equipments of materials handling. It influences the civil engineers in project planning. Mining In both underground mines and open pit operations, there is now a variety of equipment for extraction, handling and transportation of coal and ore. Cost of extracting the materials has been reduced to the minimum. Power Materials handling equipment for handling fuel and ash are needed. Machine Tools The design of many processing machines is influenced by the need for integrating various material handling features or attachments to modern machine mechanisms. Truck building
1
The automotive engineer develops trucks and trailer as efficient materials handling vehicles, designed for speedy loading and unloading, ensure cargo is secured properly, and safe transportation of a variety of materials. Rail road car builders The above are involved in improved rail road cars, development of terminal equipment, improvement in materials handling procedure for loading and securing freight and transferring or unloading it at terminals. Barge and Ship building New handling devices and improved kinds of marine carriers are manufactured in this industry. Aircraft Better cargo and storage methods for air transport where materials handling is concerned. Following are the main importance of material Handling: •
•
•
•
Different studies of the past pertaining to different industries indicated that the handling costs alone accounts for ~20-25% of the entire manufacturing costs, as the result of use of methods and equipment. It is generally found that each part component is handled about 50 times, passing through the manufacturing chain. Usually, about 59 tons of materials are handled for every single ton of finished goods. Material handling ensures increased safety from permanent and temporary disabilities. The methodology reduces claims for damages in parts and materials.
Material handling in the mechanised way relieves the drudgery for men having had busy with man handling jobs. The primary objective of a material handling system is to reduce the unit cost of production. The other subordinate objectives are: •
Reduce manufacturing cycle time
•
Reduce delays, and damage
2
•
Promote safety and improve working conditions
•
Maintain or improve product quality
•
Promote productivity
-
Material should flow in a straight line
-
Material should move as short a distance as possible
-
Use gravity
-
Move more material at one time
-
Automate material handling •
Promote increased use of facilities
-
Promote the use of building cube
-
Purchase versatile equipment
-
Develop a preventive maintenance program
-
Maximize the equipment utilization etc. •
Reduce tare weight
•
Control inventory
3
Thrust breaks Thrust reversal, also called reverse thrust, is the temporary diversion of an aircraft engine's exhaust so that the exhaust produced is directed forward, rather than aft. This acts against the forward travel of the aircraft, providing deceleration. Thrust reverser systems are featured on many jet aircraft to help slow down just after touch-down, reducing wear on the brakes and enabling shorter landing distances. Such devices affect the aircraft significantly and are considered important for safe operation by airlines. There have been accidents involving thrust reversal systems. Reverse thrust is also available on many propeller-driven aircraft through reversing the controllable pitch propellers to a negative angle. The equivalent concept for a ship is called astern propulsion
Principle and uses A landing roll consists of touchdown, bringing the aircraft to taxi speed, and eventually to a complete stop. However, most commercial jet engines continue to produce thrust in the forward direction, even when idle, acting against the deceleration of the plane.[1] The brakes of the landing gear of most modern aircraft are sufficient in normal circumstances, but for safety purposes, and to reduce the stress on the brakes,[2] another deceleration method is needed. In scenarios involving bad weather, where factors like snow or rain on the runway reduce the effectiveness of the brakes, and in emergencies like rejected take-offs, this need is more pronounced.[3] A simple and effective method is to reverse the direction of the exhaust stream of the jet engine and use the power of the engine itself to decelerate. Ideally, the reversed exhaust stream would
be directed straight forward.[4] However, for aerodynamic reasons, this is not possible, and a 45° angle is taken, resulting in less effectiveness than would otherwise be possible. Thrust reversal can also be used in flight.[5] There are three common types of thrust reversing systems used on jet engines: the target, clam-shell, and cold stream systems. Some propeller driven aircraft equipped with variable pitch propellers can reverse thrust by changing the pitch of their propeller blades. Most commercial jetliners have such devices, and it also has applications in military aviation.
Types of thrust reversal systems Small aircraft typically do not have thrust reversal systems, except in specialized applications. On the other hand, large aircraft (those weighing more than 12,500 lb) almost always have the ability to reverse thrust.[citation needed] Reciprocating engine, turboprop and jet aircraft can all be designed to include thrust reversal systems. Propeller-driven aircraft
Variable pitch propellers of an EC-2 Hawkeye
Propeller-driven aircraft generate reverse thrust by changing the angle of their controllable pitch propellers so that the propellers direct their thrust forward. This reverse thrust feature became available with the development of controllable-pitch propellers, which change the angle of the propeller blades to make efficient use of engine power over a wide range of conditions. Singleengine aircraft tend not to have reverse thrust. However, single-engine turboprop aircraft such as the PAC P-750 XSTOL, Cessna 208 Caravan, and Pilatus PC-6 Porter do have this feature available One special application of reverse thrust comes in its use on multi-engine seaplanes and flying boats. These aircraft, when landing on water, have no conventional braking method and must rely on slaloming and/or reverse thrust, as well as the drag of the water in order to slow or stop. In addition, reverse thrust is often necessary for maneuvering on the water, where it is used to make tight turns or even propel the aircraft in reverse, maneuvers which may prove necessary for leaving a dock or beach.
Jet aircraft
On aircraft using jet engines, thrust reversal is accomplished by causing the jet blast to flow forward. The engine does not run or rotate in reverse; instead, thrust reversing devices are used to block the blast and redirect it forward. High bypass ratio engines reverse thrust by changing the direction of the fan airflow, since the majority of thrust is generated by this section, as opposed to the core. There are three jet engine thrust reversal systems in common use Target type
Target 'bucket' thrust reverser deployed on the Tay engines of a Fokker 100
The target system uses a set of hydraulically-operated 'bucket' type doors to reverse the hot gas stream; in normal thrust mode, these doors form a convergent-divergent final nozzle for the engine. In the original implementation of this system, on the Boeing 707, two reverser buckets are hinged so that when they deploy, they intrude into the exhaust of the engine, capturing and reorienting the jet blast. This type of reverser is usually clearly visible at the rear of the engine during use. Clam-shell type
The clam-shell door, or cascade, system is pneumatically-operated. When activated, the doors rotate to open the ducts and close the normal exit, causing the thrust to be directed forward.The cascade thrust reverser is commonly used on turbofan engines. On turbojet engines, this system would be less effective than the target system, as the cascade system only makes use of the turbine airflow and does not affect the main engine core, which continues to produce thrust. Cold stream type
Pivoting-door thrust reversal seen on the CFM-56 engines of an Airbus A340-300
In addition to the two types used on turbojet and low-bypass turbofan engines, a third type of thrust reverser is found on some high-bypass turbofan engines. Doors in the bypass duct are used to redirect the air that is accelerated by the engine's fan section but does not pass through the combustion chamber (called bypass air) such that it provides reverse thrust.[3] The cold stream reverser system is activated by an air motor. During normal operation, the reverse thrust vanes are blocked. On selection, the system folds the doors to block off the cold stream final nozzle and redirect this airflow to the cascade vanes. This system can redirect both the exhaust flow of the fan and of the core. The cold stream system is known for structural integrity, reliability, and versatility. During thrust reverser activation, a sleeve mounted around the perimeter of the engine nacelle moves aft to expose cascade vanes which act to redirect the engine fan flow. This thrust reverser system can be heavy and difficult to integrate into nacelles housing large engines.
Operation
Reverse thrust levers forward of the main levers, seen on a Boeing 747-8
In most cockpit setups, reverse thrust is set when the thrust levers are on idle and by pulling them further back. Reverse thrust is typically applied immediately after touchdown, often along with spoilers, to improve deceleration early in the landing roll when residual aerodynamic lift and high speed limit the effectiveness of the brakes located on the landing gear. Reverse thrust is always selected manually, either using levers attached to the thrust levers or moving the thrust levers into a reverse thrust 'gate'. The early deceleration provided by reverse thrust can reduce landing roll by a quarter or more.Regulations dictate, however, that a plane must be able to land on a runway without the use of thrust reversal in order to be certified to land there as part of scheduled airline service.
Once the aircraft's speed has slowed, reverse thrust is shut down to prevent the reversed airflow from throwing debris in front of the engine intakes where it can be ingested, causing foreign object damage. If circumstances require it, reverse thrust can be used all the way to a stop, or even to provide thrust to push the aircraft backward, though aircraft tugs or towbars are more commonly used for that purpose. When reverse thrust is used to push an aircraft back from the gate, the maneuver is called a powerback. If the full power of reverse thrust is not desirable, thrust reverse can be operated with the throttle set at less than full power, even down to idle power, which reduces stress and wear on engine components. Reverse thrust is sometimes selected on idling engines to eliminate residual thrust, in particular in icy or slick conditions, or when the engines' jet blast could cause damage In-flight operation
A vortex made visible as powerback is used on a Boeing C-17
Some aircraft are able to safely use reverse thrust in flight, though the majority of these are propeller-driven. Many commercial aircraft cannot use reverse thrust in flight. Exceptions include Russian and Soviet aircraft that are able to reverse thrust in flight (mostly before touchdown). In-flight use of reverse thrust has several advantages. It allows for rapid deceleration, enabling quick changes of speed. It also prevents the speed build-up normally associated with steep dives, allowing for rapid loss of altitude, which can be especially useful in hostile environments such as combat zones, and when making steep approaches to land. The Hawker Siddeley Trident, a 120- to 180-seat airliner, was capable of descending at up to 10,000 ft/min (3,050 m/min) by use of reverse thrust, though this capability was rarely used. Concorde could use reverse thrust in the air to increase the rate of descent. Only the inboard engines are used, and the engines are placed in reverse idle only when subsonic and below 30,000 ft. This will increase the rate of descent to around 10,000 fpm. The US Air Force's C-17A is one of the few modern aircraft that uses reverse thrust in flight. The Boeing-manufactured aircraft is capable of in-flight deployment of reverse thrust on all four engines to facilitate steep tactical descents up to 15,000 ft/min (4,600 m/min) into combat environments (a descent rate of just over 170 mph, or 274 km/h). The Saab 37 Viggen (retired in November 2005) also had the ability to use reverse thrust before landing, allowing many Swedish roads to double as wartime runways.
The Shuttle Training Aircraft, a highly modified Grumman Gulfstream II, uses reverse thrust in flight to help simulate Space Shuttle aerodynamics so astronauts can practice landings. A similar technique was employed on a modified Tupolev Tu-154 which simulated the Russian Buran space shuttle. Effectiveness The amount of thrust and power generated are proportional to the speed of the plane, making reverse thrust more effective at high speeds. For maximum effectiveness, it should be applied quickly after touchdown. If activated at low speeds, foreign object damage is possible. There is some danger of a plane with thrust reversers applied momentarily leaving the ground again due to both the effect of the reverse thrust and the nose-up pitch effect from the spoilers. For planes susceptible to such an occurrence, pilots must take care to achieve a firm position on the ground before applying reverse thrust. If applied before the nose-wheel is in contact with the ground, there is a chance of asymmetric deployment causing an uncontrollable yaw towards the side of higher thrust, as steering the plane with the nose wheel is the only way to maintain control of the direction of travel in this situation. Reverse thrust mode is used only for a fraction of aircraft operating time but affects it greatly in terms of design, weight, maintenance, performance, and cost. Penalties are significant but necessary since it provides stopping force for added safety margins, directional control during landing rolls, and aids in rejected take-offs and ground operations on contaminated runways where normal braking effectiveness is diminished. Airlines consider thrust reverser systems a vital part of reaching a maximum level of aircraft operating safety.
Safety cranks Spring loaded safety crank (Sifeku) For particularly safe application
• Without pawl
• Silent
• Recoil proof
• Maintenance-free
• Totally enclosed
• Weather and temperature resis t ant
• Braking effect at both ends
• The load is held safely at every height, in the pushing and pulling direction.
• Approved by the TÜV as an independent crank
• With folding handle
Arm length 250 mm
• Square drive 17 mm
• Max. drive torque 60 Nm (braking torque) 55 A range of safety cranks used when hand-driven mechanisms require a brake and handle; examples are spec ially designed winches or jacks. Available in stainless steel – SIN type. BRAKED SAFETY CRANK Steel crank with folding handle, spring operated load pressure brake which is silent in operation and w eather resistant if regularly greased. Crank has infinitely adjustable movement with very responsive brake initiation. Does not require a ratchet assembly. • Radius – 250mm • Square drive of either 14mm or 17mm • Braking torque – 70 Nm This is a brake hub unit from the DS 250 without crank designed for use with shaft driven equipment • Also available for motorised actuation at low speed - please consult us The crank is used with a spring loaded double acting ratchet assembly (not show n), suitable for indoor or outdo or applications on request. The crank is of forged steel with folding handle and in corporates two conical nylon or brass brake discs which act as a friction assembly, dependant on the duty required and the a pplication. Two units are available with 250mm or 300mm radius cranks.
• S250: 14 or 17mm square mounting – 70 Nm Torque • S300: 14 or 17mm square mounting – 168 Nm Torque This crank is in stainless steel material and works with a separate single part ratchet assembly It is suitable for application s such as hand winches The crank has either a 14 or a 17mm square mounting hole and a 250mm radius crank • Rated torque: 70 Nm DS 250 CRANK AVAILABLE IN UNPAINTED, PAINTED OR PLATED FINISH DSK 250 BRAKE AVAILABLE IN UNPAINTED, PAINTED OR PLATED FINISH SIKU CRANK: S250/S300 AVAILABLE IN UNPAINTED, PAINTED OR PLATED FINISH SIN 250 CRANK STAINLESS STEEL
Hand crank Hand-powered cranks • • •
Mechanical pencil sharpener Fishing reel and other reels for cables, wires, ropes, etc. Manually operated car window
• •
The crank set that drives a trikke through its handles. The carpenter's brace is a compound crank.
Foot-powered cranks • •
The crankset that drives a bicycle via the pedals. Treadle sewing machine
Engines
Almost all reciprocating engines use cranks (with connecting rods) to transform the back-andforth motion of the pistons into rotary motion. The cranks are incorporated into a crankshaft.
Mechanics The displacement of the end of the connecting rod is approximately proportional to the cosine of the angle of rotation of the crank, when it is measured from top dead center (TDC). So the reciprocating motion created by a steadily rotating crank and connecting rod is approximately simple harmonic motion:
where x is the distance of the end of the connecting rod from the crank axle, l is the length of the connecting rod, r is the length of the crank, and α is the angle of the crank measured from top dead center (TDC). Technically, the reciprocating motion of the connecting rod departs slightly from sinusoidal motion due to the changing angle of the connecting rod during the cycle. This difference becomes significant in high-speed engines, which may need balance shafts to reduce the vibration due to this "secondary harmonic imbalance". The mechanical advantage of a crank, the ratio between the force on the connecting rod and the torque on the shaft, varies throughout the crank's cycle. The relationship between the two is approximately:
where is the torque and F is the force on the connecting rod. For a given force on the crank, the torque is maximum at crank angles of α = 90° or 270° from TDC. When the crank is driven by the connecting rod, a problem arises when the crank is at top dead centre (0°) or bottom dead centre (180°). At these points in the crank's cycle, a force on the connecting rod causes no torque on the crank. Therefore if the crank is stationary and happens to be at one of these two points, it cannot be started moving by the connecting rod. For this reason, in steam locomotives, whose wheels are driven by cranks, the two connecting rods are attached to the wheels at points 90° apart, so that regardless of the position of the wheels when the engine starts, at least one connecting rod will be able to exert torque to start the train.
