70 Materials tintl Their Handling 



or air hoist, such as may be used on the side floor 

 of a foundry, up to 200-ton cranes serving a large 

 assembly floor and capable of lifting an entire 

 locomotive and transporting it bodily from one 

 end of the shop to the other. 



These two types of cranes may often be worked 

 in conjunction to good advantage : the traveling 

 crane for general movements about the shop, for 

 picking up a large piece at one end of the shop 

 and carrying it to some point at the other end, 

 and the jib crane for local use at the destination. 

 It may be necessary to use a crane for a very 

 considerable time at that point. To tie up a 

 traveling crane for this purpose is not economical, 

 as it may be wanted meantime at some other point 

 in the shop. In serving heavy machine tools or 

 large foundry molds, it is, therefore, often de- 

 sirable to use both traveling and jib cranes, the 

 former for the general movement to drop the 

 piece near the machine or mold, where it is trans- 

 ferred to the jib crane which carries the piece 

 while it is being set in place. 



There are other types of cranes, such as gantry 

 cranes, bridge cranes, etc., used for heavy out- 

 side work. Their use and design present engineer- 

 ing problems which take them out of the field of 

 the average foreman. 



The Overhead Trolley. Another widely used 

 type of transportation is the overhead trolley. 

 This has many advantages. Like the traveling 

 crane, it leaves the floor free from tracks, but it 

 is more flexible, can be used with a low headroom, 



