94 



There is no doubt, however, that a large percentage of the power now spent 

 in overcoming the friction of shafting in ordinary practice could be made avail- 

 able for useful work if much of the present cumbrous lines of shafting were 

 removed. 



Manufacturers are realizing the enormous loss of power which ensues from 

 the present system of transmission, and we find a general tendency to introduce 

 different methods by which a part of this loss will be obviated. Among these are 

 the introduction of hollow and lighter shafting; higher speeds and lighter pulleys; 

 roller bearings in shaft hangers; and the total or partial elimination of the 

 shafting. 



Independent motors are often employed to drive sections of shafting and 

 isolated machines, and among these we find steam engines, electric motors, gas 

 engines and compressed air motors, although the latter have not been used for 

 this purpose to any extent in this country. 



For the average machine shop, short lengths of light shafting may be em- 

 ])loyed to good advantage, and the various machines, arranged in groups, may be 

 driven from one motor. By this method fewer motors are required and each may 

 be so proportioned to the average load that it may be run most of the time at its 

 maximum efficiency. When short lengths of shatting are employed the alignment 

 of any section is very little affected by local settling of beams or columns, and 

 since a relatively small amount of power is transmitted by each section, the shaft 

 may be reduced in size, thus decreasing the friction loss. Moreover, with this 

 arrangement, as also with the independent motor, the machinery may often be 

 placed to better advantage, in order to suit a given process of manufacture; 

 shafts may be placed at any angle without the usual complicated and often un- 

 satisfactory devices; setting-up room may be provided in any suitable location as 

 required without carrying long lines of shafting through space. This is an im- 

 portant consideration, for not only is the running expense reduced thereby but 

 the clear head room thus obtained free from all shafting, belts, ropes, pulleys and 

 other transmitting devices, can be more easily utilized for hoists and cranes, which 

 have so largely come to be recognized as essential to economical manufacture. 



There is also less liability of interruption to manufacture on account of the 

 subdivision of power, and, in case of overtime, it is not necessary to operate the 

 whole works with its usual heavy load of transmitting machinery. 



Another advantage is the adaptability of the system to changes and exten- 

 sion ; new motors may always be added without affecting any already in opera- 

 tion, and the ease with which this system lends itself to varying the speed of 

 different unit groups is a very potent factor in its favor. 



