Link 1 of slotted-link mechanism ABC rotates about fixed axis A. Slotted link 2 is connected by turning pair B to link 1 and has slot b sliding along fixed pin C. The axis of slot b does not pass through point B. When crank 1 rotates about axis A, the tip of claw a, mounted on slotted link 2, describes a connecting-rod curve in which claw a is inserted into a perforation of the film, advances the film and is withdrawn from the perforation.
$1384$LG,OC$