Constant-breadth cam 1 rotates about fixed axis A and is rigidly attached to gear 3 which meshes with gear 4, rotating about fixed axis B. Cam 1 is confined between the flat faces of yoke b of link 2 which carries claw a. Link 5 turns about fixed axis E, is connected by turning pair D to link 2 and has slot c which slides along pin d of gear 4. When cam 1 rotates, claw a of link 2 is inserted into a perforation of the film, advances the film and Is withdrawn from the perforation.
$3329$GrC,OC$