Reversible claw drive for cine projector - has offset cams to compensate for play in sprocket holes

摘要

The claw drive has two sets of cam discs which can be offset from each other so that when the drive is reversed, and the claw lever (3) rests on the second cam, the amount of offset compensates for the tolerance in the fit of the claw in the sprocket holes. The reverse projection is then in the same position as the forward projection. The claw movement normal to the film is controlled by the sides of the discs. The claw drive is simple with no further adjustment other than the two cams.