POWER TRANSMISSION BY 

 LEATHER BELTING 



CHAPTER I 



GENERAL CONSIDERATIONS AFFECTING THE TRANS- 

 MISSION OF POWER BY LEATHER BELTING 



THE function of a belt drive is to transmit a certain amount 

 of power from one pulley, rotating at a given number of revolu- 

 tions per minute, to another pulley rotating at the same or 

 a different speed. The amount of power transmitted will 

 depend upon the velocity of the belt, the tension under which 

 it is placed on the pulleys, the arc of the smaller pulley with 

 which the belt is in contact and the conditions under which 

 the belt is used. As the tension in the belt in service decreases, 

 the amount of power that will be transmitted by it will 

 decrease, and therefore an important consideration in laying 

 out a belt drive is the determination of the minimum tension 

 allowable in a belt which is to do a predetermined amount of 

 work. 



That belt drive is the most satisfactory which in the long 

 run will transmit the desired power at the lowest total cost. 

 Included in the total cost of the belt are: The first cost; 

 the cost of repairs and maintenance; and the loss caused by 

 the loss of production due to machinery shutdowns as a 

 result of belt failures during working hours. The Importance 

 of this latter item has not been appreciated to the extent 

 that it deserves, despite the fact that it often is the most 

 important of the three. A little consideration will make 



