Movement and Hosting Equipment

Materials needed for construction are to be shifted from one place to another which may involve horizontal movement, vertical movement or other type. In such cases the following movement devices, are used:

1. Vertical Movement Devices
2. Horizontal Movement Devices
3. Combined Movement Devices

1. Vertical Movement Devices

The vertical movement devices are:

1. Block and Tackle
2. Winch
3. Hoist
4. Elevators

(i) Block and Tackle

This is a vertical distance movement device which is the oldest and the simplest device. It depends on mechanical power and gives only mechanical advantage. It is the most expensive device but waste of manpower (Fig. 32.15(a)).

(ii) Winch

By winding the rope of cable on the drum vertical movement is attained. Manpower or other power can be used to wind and a greater mechanical advantage than that of block and tackle. It is after used to load heavy equipment into ships, construction equipment, etc. (Fig. 32.15(b)).

Figure 32.15 Vertical movement devices

(iii) Hoist

Hoist is operated between fixed guide rails for vertical lifting of things. Hoists are operated by hand, compressed air or by electric power. Variety of hoists is available to suit a specific purpose. The simplest is the chain hoist. Hoists are similar to elevators except that operator does not go up but operated from one point to the other (Fig. 32.15(c)).

(iv) Elevators

This is similar to hoist but with a difference that the operator can ride with the load. Among the different types of elevators, the electrical one is often used. In places where electric power can not be used hydraulic elevators are used.

2. Horizontal Movement Devices

The horizontal movement devices are:

1. Hand Trucks
2. Narrow-gauge Rail Road
3. Tractors and Trailers
4. Skids

(i) Hand Trucks

Wheel barrows and hand trucks are the simplest transporting devices which are still in use. These devices involve large amount of manpower to move a small load. The advantages of these devices are small cost, flexibility, easy transportation from one place to another (Fig. 32.16(a)).

Figure 32.16 Horizontal movement devices

(ii) Narrow-gauge Rail Road

As it is very expensive, this is adopted only in very large projects. It is used to industries like blast furnace, copper refineries and steel-rolling operations.

(iii) Tractors and Trailers

These are the commonest modes of horizontal transportation. Trailers can be lift-loaded and can be towed to tractors. Different types of trailers can be picked up by tractors. This is one of the mostly used methods of handling materials from one place to another. This is less costly compared to narrow-gauge rail.

(iv) Skids

Skids are wheeled or plain trollies over which materials can be loaded and then picked up with lift trucks. Skids can be used to load and transfer from position to position without subsequent loading and unloading. The most common skids, which can be picked up in either direction, consist of a wooden platform and four steel legs (Fig. 32.16(b)).

3. Combined Devices

Combined devices comprise the actions of lifting, lowering or transportation. Combined devices are as follows:

1. Chute
2. Lift truck
3. Forklift truck
4. Cranes
5. Conveyers

(i) Chute

Chutes are the devices which are adopted for horizontal and vertical movements. The chutes may be straight or of spiral form.

(ii) Lift Truck

These are similar to roller skids but provide provision for a large platform to lift and place the materials and move them horizontally through power to another location (Fig. 32.17).

Figure 32.17 Lift truck

(iii) Fork Lift Truck

It is provided with fork which receives the load at ground level and elevates it hydraulically to the desired height. There is no need for manual lifting. Self-loading or unloading can be carried out by providing a fork at the front end of the truck. Fork lift trucks are used in construction industry (Fig. 32.18).

Figure 32.18 Fork-lift truck

(iv) Cranes

Cranes are electrically or diesel operated equipment used to lift and move heavy materials and machinery. Cranes have wide application in construction projects, industries and in shipping yard. Cranes have three motions, viz., hoisting, derricking and slewing.

Cranes are classified as given below:

1. Derrick cranes
2. Tower cranes
3. Pillar cranes
4. Overhead or gantry cranes
5. Self-propelling boom cranes
6. Crane trucks

1. Derrick Cranes: They consist of a mast, a boom and a bull wheel on which it rotates about a vertical axis and with supporting members (also referred to as guys).Most of the derrick cranes are supported by a number of guys. The boom can revolve through 360° and passes below these guys. A bull wheel is attached to the mast and rotates it. These cranes are operated by diesel engine or by an electric motor.Guy derricks are available in lifting capacities of 5–200 tonnes and used mainly for erecting heavy structures, Fig. 32.19 (Ataev, 1985).Figure 32.19 200-tonne guy derrickThese cranes are used in construction projects like industries or multi-storeyed buildings, loading and unloading of cargoes at ports, in ship building, etc.
2. Tower Cranes: These are used mainly in erection of apartment and high-rise industrial buildings.Main advantages of tower rail-mounted cranes are their stability and a large reach of hook. Main construction is served by tower cranes of capabilities varying from 8 to 10 tonnes lifting capacities (Fig. 32.20).Figure 32.20 Tower crane for high-rise house construction
3. Pillar Cranes: Pillar cranes may be a stationary or mobile type. It is used for light load (up to 20 tonnes). In order to lift up or lower down the load a job or inclined boom is fixed to the lift and the lifting is done with the help of rope and pulley arrangement. All the movements to the crane required for a particular situation are provided by gearing and electric power drive (Fig. 32.21). Figure 32.21 Pillar crane
4. Overhead Cranes: Overhead cranes are fixed in one location and can not be moved to place to place. These are provided in big workshops, boundaries, powerhouses, chemical plants, research stations, etc. These are operated by electric power. These cranes have the advantage of providing large service area. All the operations can be done by an operator seated in the cabin (Fig. 32.22). Figure 32.22 Overhead crane
5. Self-propelling Boom Cranes: These are available in caterpillar-tracked wheeler, truck and tractor mounted varieties with diesel or electric drivers. The lifting capacity ranges from 3–160 tonnes. Caterpillar-mounted boom cranes are widely used.In order to increase the reach and the height of lift of a crane hook, a standard boom may be provided. Now-a-days cranes with telescopic booms are being increasingly employed (Fig. 32.23).Figure 32.23 Crane with telescopic boom
6. Crane Truck: Crane trucks of small size function as that of a lift truck (Fig. 32.24). These are used where the material to be moved is of heavy weight which can not be moved using skids. This can be moved easily to a desired place and handling is much easier. The cranes are rotary type so that the load can be lifted from any position. Figure 32.24 Crane truck
7. Conveyors: These are the material transportation devices used when the parts of flow of material is fixed. Because of this desired fixity, lifting and lowering of materials are done automatically. Conveyors require no stopping or starting but the operation is continuous. The transportation is effected by friction between materials being transported and the belt or roller.