Model: N21 Alternating-clamp, Friction Clutch Ratchet
In this model alternating motion of the lever will engage and disengage the two wheels to lower or raise a weight attached to the pulley. Attached to the lever is a specially shaped friction pawl situated between the two wheels that will either prevent relative motion or allow relative motion of the wheel and pawl depending on the position of the lever. Reuleaux called these devices friction clutch ratchets. In the Voigt catalog he also used the German word "Drosselklemm" literally "throttle clamp'. We have use the term 'alternating clamp' since it more accurately portrays the action of the ratchet mechanism.

Francis Moon 2004-07-00

Reference :

  • Reuleaux : Constructor (4th Ed., §248, Fig. 724, p. 160, 1893)