72 LEATHER BELTING 



Crossed Belts. The length of a crossed belt may be ob- 

 tained exactly by the formula 



The notation is the same as in the three formulae above for 

 open belts. 



Length of a Roll of Belting. The length of a belt, in feet, 

 when closely rolled is approximately equal to the sum of the 

 diameter of the roll and of the eye of the roll in inches, mul- 

 tiplied by 0.1309 times the number of turns. 



Idle Belts. It is advisable when belts are out of service 

 for any length of time to throw them from the pulleys. They 



FIG. 19. HANGER FOR IDLE BELT. 



should be suspended from hooks, however, and not allowed to 

 rest upon the shafting. This latter practice, which is alto- 

 gether too common, is not only destructive of the belts, but 

 is frequently the cause of accidents. The arrangement shown 

 in Fig. 19 should be used where belts are removed from the 

 pulleys. The hook, of f in. round iron, is suspended from the 

 ceiling by a staple. It should be long enough to reach almost 

 to the rim of the pulley, and should swing the belt clear of 

 the shaft. 



