Abstract: Method for correcting vertical framing errors during the projection of an intermittently transported perforated motion picture film by means of a film transport sprocket engaging the film perforations, said sprocket being driven by an electric motor whose rotor is connected with an angle indicator device which delivers to a regulating device controlling the electric motor, position signals corresponding to the angular position of the rotor. To correct device-specific vertical framing errors, the frame positions are measured with a geometrically precise measuring film over a plurality of frames, the individual frame positions are stored, and the position of the angle indicator disk is changed by a correction value relative to the film transport sprocket.

Abstract: A method and mechanism for adjusting the timing of a camera in the reverse mode while allowing for separate adjustment of the timing in the forward mode. In a preferred embodiment, an external switch is provided which when actuated switches the camera between the timing setting for the forward direction and the timing setting for the reverse direction. A helical driven gear which engages a drive gear driven by the motor is axially translatable between a first position corresponding to the forward direction and a second position corresponding to the reverse direction. Since it is a helical gear, the amount of axial translation adjusts the relative angular position of the shutter with respect to the frame advance mechanism.

Abstract: A mechanical drive arrangement for a cinematograph projector. A double-sided tooth drive belt passes, in succession, over a motor driven, film take-up sprocket, idler sprocket, intermittent drive sprocket, film feed sprocket and shutter drive sprocket. The intermittent drive sprocket and intermittent motion film sprocket are mounted on a rotatable disc. The axis of rotation of the disc coincides with the circumference of the intermittent drive sprocket at the point where the plane through the axes of both mounted sprockets cuts the region of engagement of the drive belt around that circumference. In consequence, rotation of the disc moves the film anchor point, on the intermittent motion film sprocket, with only slight rotation of the shutter drive. Thereby, ghosting is avoided when racking.