Free wheeling sprocket rotary gate for motion picture film

摘要

A rotary gate for digitally scanning frames of a motion picture film has a motor drive wheel and a coaxially spaced free wheel which support and engage sprocket holes in the film. The free wheel has no connection to the driven wheel other than the film which rotates the free wheel as it is driven by the drive wheel for advancing the film through the gate. A light source and sensor are provided on opposite sides of the film for illuminating the film and digitally scanning motion picture frames. Sprockets on the drive wheel are profiled to stabilize the film laterally while it is advanced for scanning of each frame. A fixed disc with a smooth track my be substituted for the free wheel for supporting the film.