5.  Rail-Guided Vehicles

These are material transport equipments consisting of motorized vehicles that are guided by a fixed rail system. These are self-propelled vehicles that ride on a fixed-rail system. The vehicles operate independently and are driven by electric motors that pick up power from an electrified rail.

The fixed rail system can be classified as,

• Overhead monorail
• On-floor parallel rails

Monorails are typically suspended overhead from the ceiling. In rail guided vehicle systems using parallel fixed rails on floor rails, the tracks generally protrude up from the floor. The vehicles operate asynchronously and are driven by an on-board electric motor. The rail guided vehicles pick up electrical power from an electrified rail. In such vehicles routing variations are possible.

6. Conveyors

These are of material transfer equipments designed to move materials over fixed paths, usually in large quantities or volumes. They can be classified as non-powered and powered systems. In non‑powered systems, the materials are moved by human workers or by gravity whilst in powered systems, materials are transported by using automated systems. There are various types of conveyors such as roller, skate‑wheel, belt, in‑floor towline, overhead trolley conveyor and cart-on-track conveyor are used in industry.

6.1  Roller conveyor

Fig. 4.6.9 Roller conveyor

In roller conveyors, the pathway consists of a series of rollers that are perpendicular to the direction of travel as shwon in Fig. 4.6.9 . Loads must possess a flat bottom or placed in carts. Powered rollers rotate to drive the loads forward.

6.2  In-Floor Tow-Line Conveyor

It consists of a four wheel cart powered by moving chains or cables placed in trenches in the floor. Carts use steel pins which project below floor level and engage the chain for towing. The pins can be pulled out to allow the carts to be disengaged from towline for loading and unloading purpose.

6.3  Overhead Trolley Conveyor

Fig. 4.6.10 Overhead trolley conveyor

In this equipment a motorized vehicle runs over an overhead track. By moving this trolley, loads can be conveyed with the help of hook as shown in Figure 4.6.10 . Trolleys are connected and moved by a chain or cable that forms a complete loop. These are often used to move parts such heavy dies, molds, and assemblies of machine components.

6.4  Belt Conveyors

Fig. 4.6.11 Belt drive

Belt conveyors consist of a continuous loop of belt material (Fig.4.6.11) . Half of the length is used to deliver the materials and the other half is for idle return. The drive roll powers the belt. The belt conveyors are of two types, namely flat belts and troughed belts. These are very commonly used in industry to convey light to heavy, solid, loose commodities such as food grains, sugar, cement bags, coal etc. They are also widely used to transfer small to large size cartons/boxes of products. Detail analysis and design of conveyors is out of the scope of this course.

7.  Rotary indexing table

Fig. 4.6.12 Rotary indexing table

These are used for the synchronous transfer of small parts from one station to the other station at single work center. The workparts are indexed around a rotary table. The workstations are stationary and usually located around the outside periphery of the dial as shwon in Fig. 4.6.12. The parts riding on the rotating table are positioned at each station for their processing or assembly operation. This type of equipment is called as an indexing machine or dial index machine. These are generally used to carry out assembly operations of small sized products such as watches, jewelery, electronic circuits, small molds/dies, consumer appliances etc.