Controls for synchronizing audio signals with film advancement in a projector

摘要

A synchronized audio visual system including an audio program source capable of producing a film advance signal at predetermined intervals and a projector interconnected therewith. The projector has a source of light for passing light through an aperture in the projector and film is directed along a pathway into and out of alignment with the aperture for projection of individual frames thereof in sequence. A motor is used for initiating advance of the film in response to advance signals from the audio source in a predetermined sequence. The motor directs an advance mechanism including a rotating member with a drive projection extending therefrom for rotating into and out of engagement with film support and drive structure for the film. The period of advance of the film is controlled by each stroke of the rotating member and is related to a film advance signal from the audio source. Assisting in the limitation is the rotating member which forms a switch connected to the motor to close a circuit when in contact with the drive structure for the film and open the circuit otherwise. In this manner, the period of film advance is controlled and synchronized with the audio program source.