An exhaustive treatment of all the available types of power operated materials handling equipment is not possible nor desirable here. For our purpose material handling is being considered in selection to store house and the stock yard work only.
The Commonly Used Power Driven Material Handling Equipment
1. Fork-lift Trucks. These are heavy duty machines with large wheels for stock yard work. Some trucks are suitable for operation both inside and outside, these have smaller wheels. Other machines are pedestrian controlled, i.e. , the operator walks behind the vehicle. The heavier types have diesel or petrol engines; other are electrically driven and so avoid the nuisance of smoke or fumes.
The normal attachment is a fork consisting of two flattened prongs which can be pushed under a load (or into a pallet) and then raised automatically to lift the load. Such pallet trans-porters are suitable for lifting, transporting and laying down stores. They can not stack. Some trucks have detachable forks which can be re-placed by shovels, clamps or crane attachments. They are not suitable for transporting goods for long distances or for really heavy materials. Where handling by fork lift is done, gang ways must be wide enough to allow the tracks to man-oeuvre.
2. Platform Trucks. These are of two types fixed platform and platform lift trucks. The lifting platform variety is based on the same principle as a low lift fork lift machine, but instead of forks it has a platform which can run under a suitable container or stillage and lift the load clear of the floor. Both type of platform trucks are but used where Platform stores have to be carried fairly long distances.
3. Tractors. Tractors of various size are used in store houses and stock yards. The use of two or more trailers per tractor is more economical because the tractor can be transporting one or more trailers while others are being loaded or unloaded. This kind of vehicle is like platform trucks most suitable for long hauls. Some tractors can be fitted with various attachments for particular jobs such as forks for handling pallets or buckets for stand or gravel. Tractors can also be useful for shunting railway wagon or pulling narrow gauge rail trolleys.
3. Overhead Electric Cranes. Weight of stores to be handled seldom exceed 10 tonnes at a time and this is well within the capacity of overhead cranes. Five tonne and ten tonne overhead electric travelling cranes are most commonly used in stores. There are two main types— floor controlled and cab controlled.
In the first case there is a control panel attached to a cable leading from the crane bridge overhead; the operator holds this panel in his hand to control the machine and walks up and down underneath it as it travels to and fro along its rails which are supported on the columns of the building.
In the second case the crane is managed from above by an operator sitting in a cab mounted in the crane bridge. Floor control is best where use of the crane is spasmodic. Cab control is quicker to operate and more satisfactory when the machine is in continuous use but it is more expensive. of the overhead travelling
4. Goliath Cranes. It is a special version crane. Instead of erecting an overhead gantry track all along the travelling distance, the crane is mounted on legs fitted with wheels and the whole structure moves along rail-way lines set in the ground.
5. Mobile Jib Crane (Road). It is mounted on wide wheeled chassis which re-quire wide gang ways and the long jibs need high doorways for clearance. Machines of this nature are not suitable for inside work. But they are very useful in a stock yard. They can be designed for much heavier lifts but the commonest types in use for stores work are from 2 to 6 tonnes with jibs upto 12 metres or 80. Which can be lifted or lowered to increase or decrease the reach of the crane. It can unload box wagons. It is self propelled and mobile and can go anywhere.
6. Screw Conveyor. A screw conveyor or spiral conveyor consists of a revolving shaft provided with continuous or broken spiral flighting. The shaft operates within an enclosed or open casing or trough, and material is thus transferred from one place to another. The screw is designed in such a way that it operates the indirectionally. An electric motor drives the screw at a suitable speed through a gear train. Screw conveyors are commonly employed for conveying non-abrasive and fine materials
7. Pneumatic Conveyors. The pneumatic tube system is used in a number of factories for transport at a speed of about 9 meters per second of small tool samples, matrices and similar parts between different buildings.
Samples of iron or steel from a batch of castings, may be passed from the foundry to the works laboratory with minimum of delay. It consists of a series of pneumatic tubes connecting the various shops to a control desk. An impeller or turbine maintains a constant vacuum or pressure in the tubes so that when a tubular carrier is inserted in the tube it is carried by air pressure. By means of color codes or numerals on the body or the carrier the operator at the control desk is able to reroute the carrier to the correct department.
8. Chain Conveyors. For continuous transport of goods, the overhead system of mechanical handling. It makes possible to carry goods or components through a complete circuit bringing the parts to the points wherry the operation are to be carried out and moving them out of the way where they are not required-turning around corners; communicating from one building to another without impending grounding traffic and generally performing an movement which may be necessary.
9. Ramps: Ramp for loading and unloading in trucks wagons are constructed permanently or fabricated for mobile operation.