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 passes through point B. When crank 1 rotates about axis A, the tip of pin a of slotted link 2 describes a connecting-rod curve in which the pin is inserted into a perforation of the film, advances the film and is withdrawn from the perforation. The position of the pin is adjusted by screw d.
$1385$LG,OC$