GUIDE PULLEYS 



79 



Quarter- twist belts may be used to drive shafts which make 

 angles with one another of other than go degrees, if the rule 

 is observed that the points at which the belt leaves the pulleys 

 are in the straight line determined as explained previously. 

 The method of laying out holes in the floor is the same as 

 that used for shafts at right angles, except that the arc MN 

 on the pulley outline extends only to a line drawn from the 

 point / parallel to the face of the lower pulley. This is the 



FIG. 23. METHOD OF LOCATING GUIDE PULLEYS. 



line JR in the sketch showing the angular arrangement of 

 pulleys in Fig. 22. 



Guide Pulleys. Where two shafts that are not parallel and 

 that do not intersect are to be connected by belting, and the 

 conditions are such as to make a quarter-twist belt inadvisable, 

 guide pulleys are used. The function of the guide pulley 

 is tj alter the direction of the belt and cause it to run squarely 

 onto the receiving pulley. The location of the guide pulley 

 with the reference to the main pulleys is determined by the 

 intersection of the planes passing through the center of the 



