6 LEATHER BELTING 



While the use of Nagle's formula will give better results than 

 will the rule of thumb formulae, nevertheless the tensions in 

 the belt will be much higher than are dictated by the good 

 practice which has resulted from later investigations, notably 

 those of Frederick W. Taylor, supplemented by the further 

 studies of Carl G. Barth. 



While the work of Mr. Nagle represented a long step in 

 advance in belting practice, the investigations of Taylor, 1 

 extending over nine years, and dealing with belts in actual 

 service, really form the basis upon which the most approved 

 practice of today is built. These investigations revealed 

 the advantages of low tensions and heavy belts, the accurate 

 measurement of the tension under which the belt is placed 

 on the pulleys, the regular inspection, repair and retighten- 

 ing of belts, and the maintenance of the working tension be- 

 tween certain well defined limits. Taylor's investigations 

 are discussed in greater detail in Chapter II. 



Taking Mr. Taylor's results as a starting point, and 

 examining the work of other reliable investigators in connec- 

 tion with them, Carl G. Barth 2 has extended the work of 

 Taylor, which applied mainly to slow-running belts, to high- 

 speed belts such as are found in general service, and at the 

 same time he has developed a mathematical treatment of 

 the subject, which is the most accurate of any yet presented. 

 As a result of the work of Barth, belting practice can now 

 be said to be standardized, and the proportioning of a belt 

 drive removed from the domain of rule of thumb to that of 

 exact science. Mr. Earth's work is presented in detail in 

 Chapter IV, and tables showing the horsepower that can be 

 transmitted by a belt under different conditions of service, 

 as calculated according to the formulae derived by him, are 

 presented on pages 91 to 94. The practice of Barth in 



1 Transactions, American Society of Mechanical Engineers, vol. xv, p. 204. 



2 Ibid., vol. xxxi, p. 29. 



