CHAPTER V 

 BELT MAINTENANCE 



IN the previous chapters, stress has been laid on the 

 necessity of putting a belt on the pulleys under a certain 

 predetermined tension, depending upon the horsepower it 

 is to transmit and the velocity at which it is to be operated, 

 and of retightening it to this tension whenever it falls to a 

 predetermined minimum. While it is possible to weigh the 

 tension in the belt at intervals while it is directly on the pul- 

 leys, it is inconvenient to do so, and the " belt bench " forms 

 a useful and convenient appliance for insuring that belts 

 are kept up and maintained at the proper tension. 



The Belt Bench. A form of belt bench which has been 

 widely used is shown in Fig. 8. It is made by the Tabor 

 Manufacturing Co., of Philadelphia. This bench consists 

 of a channel which forms a runway for a carriage on which 

 is mounted a movable drum. The channel is supported upon 

 cast-iron chairs and brackets and a bench top is placed over 

 the channel. A fixed drum is at one end of the channel. 

 The channel is graduated to indicate distances of i ft. in 

 the length of the belt, while the carriage carrying the mov- 

 able drum is graduated in inches and fractions of an inch 

 of length of belting, as shown in Fig. 9. The length of the 

 belt needed for a given pair of pulleys is measured by means 

 of a steel tape passed around the pulleys, and the movable 

 drum on the carriage of the belt bench is set at the graduation 

 indicated by the reading of the tape. The carriage having 

 been set to the length of the belt required, the belt is passed 

 around the drums and the two ends are passed through 

 belt clamps and held firmly therein. The belt is set at the 

 same distance from the edge of each drum, by means of 



45 



