FILM TENSION ABSORBING SYSTEM

摘要

A film tension absorbing mechanism is provided on a motion picture projector for absorbing film tension shock in the film strip. The tension absorbing mechanism includes a first system comprising the combination of a pivotally mounted, biased film exit guide roller for absorbing a portion of the tension and a tension absorbing sprocket drive to permit relative movement between the film strip and the sprocket. The tension absorbing sprocket includes a sprocket wheel and a relatively movable sprocket tooth ring rotatably mounted for generally conjoint rotation. The sprocket tooth ring is biased in a direction opposite the rotation of the sprocket wheel so that film tension shock can be absorbed as the sprocket tooth ring rotates relative to the sprocket wheel in a direction against the biasing force. A second system also is provided and includes a bi-directional tension absorbing drive sprocket for absorbing film tension shock in two directions. A sprocket tooth ring is mounted on a sprocket wheel for relative rotation therewith in two directions. A biasing mechanism provides for a different biasing torque to be applied to the tooth ring as it rotates in one direction versus rotation in another direction relative to the sprocket wheel.