Torque control for cine projector - has speed regulated friction force to prevent jamming

摘要

A cine projector drive has friction drive wheels to grip the film and pull it onto the take-up spool. The friction drive is supported by a gate drive, and is speed controlled to provide more torque if the perforation drive drops out. The additional drive is obtd. by a slip clutch and a free running coupling to operate directly when the film speed drops. The friction drive is sufficient to provide all the torque to prevent the film from stopping and charring.