854 TRASSACTIoys OF THE AilEmCAN INSTITUTE. 



Amekican Methods of Tkansmitting Mechanical Power. 



Mr. F. "VV. Bacon, of Jersey City, read portions of an elaborate 

 paper on the transmission of power at a high speed by belts, gener- 

 ally adopted in American shops in contradistinction to the slow 

 motion and gearing used in similar establishments abroad. After 

 giving rules for the calculation of width, speed, etc., the writer pro- 

 ceeded to consider the causes that impair the efficiency of belts after 

 their proper selection and fitting to the pulleys. Among these were 

 mentioned the common one of stretching ; the liability of shafts to 

 be sprung out of line, resulting in the running off of the belt at one 

 side of the pulley ; the coming of the belt in contact with another, 

 thus producing abrasion and loss of power ; the drying of the belt, 

 and consequent diminution of adhesion and loss of power. Attention 

 to points like these is of course essential, even when the utmost care 

 has been exercised in adapting the belts to use. 



The w-riter advocated the softening of new belts by the use of 

 appropriate unctuous substances, by which they M'ill be enabled to 

 come in more immediate contact with the pulleys. He stated that 

 under a comparatively high temperature, say Q^'^ to TS*^, as in sum- 

 mer, he had found a dressing composed of equal parts of tallow and 

 castor-oil to be superior. For lower temperature, the proportion of oil 

 may be increased, while during the heat of summer the oil alone may 

 be used. Furthermore, when once treated with castor-oil neither 

 mice nor other vermin will attack the belt. 



The writer also spoke of the desirability, when crossed belts must 

 of necessity be used, of crossing the subordinate instead of the prin- 

 cipal belts, as by this means the minimum loss of power from the 

 friction of the belt may be obtained. There are many cases in which 

 shafts cannot be placed parallel with each other, and, aside from the 

 use of bevel or skew gearing, there lies only the choice between the 

 use of universal joints and crossed belts. The universal joint is not 

 open to the objection of percussion, but the movement communicated 

 thereby is not uniform, and, moreover, the centrifugal force throws 

 off the oil, so that at high speed the requisite lubrication cannot be 

 obtained. The use of crossed belts is not open to these drawbacks ; 

 but when these are used, the speed should be as great as circumstan- 

 ces may permit, in order to enable the belt to be had as narrow as 

 possible, to facilitate its action despite the crossing of the same. In 

 those instances where the width of the belt cannot be reduced to the 

 desired degree, the writer advocated the ])lacing of a supplemental 



