Cam 1 rotates about fixed axis A. Pawls 3 slide in fixed guides a of the housing and springs 5 force them inward. Disk 2 turns about axis A and has slot b into which a pawl 3 drops periodically. Torsion spring 4 encircles the axis of rotation of cam 1 and one of its ends bears against pin c of cam 1 and the other against pin d of disk 2. When cam 1 is turned by handle f in either direction, it disengages pawl 3 from disk 2 which is turned by spring 4 to its next position where another pawl 3 drops into slot b.
$3349$CR,SE$