A GOVERXOK FOR TELEPHONE DIALS 



1269 



DIAL AND GOVERNOR OPERATION 



In dialing, the tingerwheel is rotated through an angle proportional to 

 the number being dialed and then released. Energy stored in the motor 

 spring, Fig. 2, causes the mechanism to return to the start position. For 

 each 30° rotation of the fingerwheel during run-down, the intermediate 

 gear rotates one-half revolution and the cam pinion and pulsing cam ro- 

 tate one full revolution. (3nce the pulsing pawl is in position, each revolu- 

 tion of the pulsing cam in the run-down direction results in a pulse being 

 placed on the telephone loop. The intermediate gear also meshes with a 

 governor pinion which is coupled to the governor shaft and governor 

 through a spring clutch.* This clutch decouples the governor from the 

 fingerwheel on windup to reduce the windup torque. On run-down the 

 go\'ernor rotates two full revolutions for each 30° rotation of the finger- 

 wheel. 



Fig. IB — Rear view of 7-tj'pe dial. Left, speed governor, center, off-normal 

 contact and right, pulsing mechanism. 



Wiebusch, C. F., The Spring Clutch, J. Appl. Alech., Sept., 1939. 



