Three-lobe constant-breadth cam 2 and eccentric cam 3 are keyed to shaft 1 and rotate about fixed axis A. Slide 4 reciprocates vertically in fixed guides b-b of the base and is operated by cam 2. Slide 5, carrying operating claws a, reciprocates horizontally in guides d-d of slide 4 and is operated by cam 3. When shaft 1 rotates, cam 3 inserts claws a into perforations of the film and then, after the film is advanced by cam 2, with-draws the claws from the perforations.
$3106$SmC,OC$