Three-lobe constant-breadth cam 1 rotates about fixed axis A. Contour a of cam 1 is enclosed by a rectangular opening of follower 2 which has claw b. Follower 2 has straight slot d whose axis does not pass through point A and which slides along fixed pin 3. When cam 1 rotates, follower 2 has a complex motion in which claw b is inserted into a perforation of the film, advances the film and is withdrawn from the perforation.
$3107$SmC,OC$