Slide projector with continuous slide transport - uses helical worm gear to move slides and has retractable slide positioner

摘要

The magazine is rotated into slide engagement positions by the action of the helical thread wall on at least two peripheral teeth. An electric motor rotates the screw via a gear wheel. The thread pitch is variable with a central neutral zone to allow steady motion at the moment when the motor halts it. The screw and magazine may be rotated in either direction and continuously, permitting easy searching for slides. No mechanisms, which are subject to wear, are required to hold the magazine in successive discrete positions. Movement from one slide position to the next is smooth. The rotation of the screw shaft lends itself to easy automatic slide counting and motor stopping control.