Shuttle speed control device

Abstract

Disclosed for a sound motion picture camera is an improved shuttle speed trol device including a film loop sensor sensitive to slight variations in the film loop for causing the speed of the shuttle to be changed by a simple brake device utilizing powers of the drive motor whereby less force is required for sensing the size of the film loop to maintain picture-sound synchronization.

What I claim is: 
     
       1. A shuttle speed control device for .[.a.]. sound motion picture .[.camera.]. .Iadd.cameras and projectors .Iaddend.including a drive motor having an output shaft driving a shuttle for transporting film intermittently through an exposure station and a capstan for transporting film constantly through a sound station, and a film loop sensor arranged between the exposure station and the sound station, the control device comprising: a first half pulley fixed to said motor output shaft;   a second half pulley coupled to said first half pulley and adjustable along said motor output shaft;   transmission means arranged about said half pulleys and coupled to said shuttle for powering said shuttle;   a brake disk rotatably supported on said output shaft;   a first pawl member arranged on said second half pulley;   a second pawl member arranged on said brake disk for engagement with said first pawl member;   a brake member on said film loop sensor movable responsive to variations in the size of the film loop whereby .[.an increase.]. .Iadd.a decrease .Iaddend.in film loop size causes said brake member to engage said brake disk to increase the rate of operation of said shuttle relative to the rate of rotation of said capstan, and .[.decrease.]. .Iadd.an increase .Iaddend.of said film loop size causes said brake member to release said brake disk to decrease the rate of operation of said shuttle relative to the rate of rotation of said capstan.   
     
     
       2. A shuttle speed control device as recited in claim 1 wherein said pawls cause axial movement of one of said half pulleys when said brake member is engaged and removed from said brake disc responsive to actuation of said loop sensor. 
     
     
       3. A shuttle speed control device as recited in claim 2 wherein said half pulleys cause said shuttle to be driven at different rates responsive to the axial displacement of said pulleys.