Plate cam 1 rotates about fixed axis A. Connecting rod 5 is connected by turning pairs B and C to cam 1 and to slide 4 which reciprocates along fixed guides a-a. Rigidly attached to slide 4 is flat spring 2 which contacts the working surface of cam 1. When cam 1 rotates, claw b of spring 2 is inserted into a perforation of the film, advances the film and is withdrawn from the perforation.
$3211$CmL,OC$