Rigidly attached constant-breadth cam 1 and cylinder ridge cam 2 rotate about fixed axis A-A. Follower 4 reciprocates in fixed guides c-c. Cam 1 is confined between the flat horizontal faces of yoke b of follower 4. The sums of all the opposing radius vectors of cam 1 are constant and equal to the distance between the faces of yoke b. The profiled ridge of cam 2 slides in slot d of pin 3 which slides in a hole in follower 4 and reciprocates together with the follower. When cams 1 and 2 rotate, the latter inserts the claw of pin 3 into a perforation of the film which is then advanced by follower 4. After this, cam 2 withdraws pin 3 from the perforation.
$3105$SmC,OC$