Ratchet wheels 2 and 4 are keyed on shaft 1 and rotate together about fixed axis A. The wheels have the same number of teeth but those on one wheel are shifted by one half pitch with respect to those on the other wheel. Pawl 3 can slide sideways, reciprocating so that it alternately engages the teeth of wheels 2 and 4. As a result, shaft 1, to which a constant torque is applied, rotates intermittently through angles corresponding to one half pitch of the teeth of wheels 2 and 4.
$2694$RG,3L$