200 



HANDBOOK OF MECHANICAL DESIGN 



Universal Joinf^ 



Fig. 419. — Devices for avoiding belt wear when using speed cones. At left, creeping acting of belt is not entirely 

 eliminated, and universal joints present a problem of cost and maintenance. At right, a roller is substituted for the 

 belt, giving more compactness. 



Oufpuf 

 shaft, 



Fig. 420. — The main component of this drive 

 is a hollow cone driven by a conical roller. Speed 

 ratio changed by sliding driving unit in V guides. 

 Note that when the roller is brought to the center 

 of the hollow cone, the two run at identical speed 

 with the same characteristics as a cone clutch. 

 This feature makes the system attractive where 

 heavy torque at motor speed is required in com- 

 bination with lower speeds for light preliminary 

 operations. 



Rollers - 



Driven^ 

 cone 



/Driving 

 f- pulley 



"Rocker shaft 



Fig. 421 . — In this transmission, the cones are mounted 

 in Une and supported by the same shaft. One cone is 

 keyed to the main shaft and the other is mounted on a 

 sleeve. Power is transmitted by a series of rocking 

 shafts and rollers. Pivoting rooking shafts and allowing 

 them to slide change the speed ratio. 



