Round eccentrics 2 and 3 are keyed to shaft 1 and rotate about fixed axis D. Eccentric 2 is confined between the flat parallel faces of yoke 4, and eccentric 3 between the flat parallel faces of yoke 5 which oscillates about fixed axis A. Yoke 4 is connected to the base by flat springs 6 and 7, and to yoke 5 by flat spring 8 on which claws a are mounted. When shaft 1 rotates, claws a describe complex curves in which they are inserted into perforations of the film, advance the film and are withdrawn from the perforations.
$3216$CmL,OC$