Photographic film precision advance and positioning mechanism - uses two toothed wheels, one driving and other tensioning film

摘要

The perforated film precision advance and positioning mechanism has a chassis with two toothed rollers (8, 9). These rollers (8, 9) are placed on either side of the chassis. Their teeth fit into the perforations on the two edges of the film. One of the rollers (9) is connected to driving means (34-39). The roller (a) advances the film against the retaining action of the other roller (8). This roller (8) has friction means (27) acting on the axis (10) of the roller. It is connected to the chassis by spring means (28) which tension the film at then end of an advance movement.