Cassette safety lock for film end - has sprung tag at end of sprocket hole engaged by catch on cassette wall

摘要

The film is provided with a safety sprocket hole which is gripped by a safety catch on the cassette wall to prevent the film from being completely drawn into the take-up spool. The hole is rectangular with a spring tab (13) at one end to act as a buffer onto the sprocket claw to prevent the film from tearing. The tag is formed by two short cuts along the sides of the hole. It provides a damped stop for the film claw. Several holes and claws can be positioned alongside each other for added security.