Electronically controlled variable rate film feeding mechanism for motion picture projectors

Abstract

Abstract IN A FILM FEEDING MECHANISM FOR A MOTION PICTURE PROJECTOR OF THE TYPE HAVING A FILM CLAW MOUNTED FOR UPAND-DOWN MOVEMENT IN A FILM ADVANCING DIRECTION AND IN-AND-OUT MOVEMENT IN A FILM ENGAGING AND DISENGAGING DIRECTION RELATIVE TO A FILM ADVANCE THE FILM THROUGH THE PROJECTOR, THE IN-AND-OUT MOVEMENT BEING EFFECTED INTERMITTENTLY BY A SOLENOID. THE CONTROL CIRCUIT FOR THE SOLENOID INCLUDES A VARIABLE OSCILLATOR PRODUCING A SIGNAL THE FREQUENCY SETTING OF WHICH DETERMINES THE FREQUENCY OF THE IN-AND-OUR MOVEMENT OF THE CLAW, AND HENCE THE RATE OF FILM ADVANCE, DURING CONTINUOUS CONSTANT-SPEED RECIPROCATION OF THE CLAW IN THE UP-AND-DOWN DIRECTION. THE OSCILLATOR MAY CONTROL THE CIRCUIT THROUGH AN ELECTRONIC SWITCH CONTROLLED BY THE OSCILLATOR, AND TIMING OF THE SOLENOID ACTION RELATIVE TO THE CLAW POSITION IS EFFECTED BY A TIMING SWITCH OR SWITCHES, PREFERABLY CAM OPERATED.

Inventors

• 👤 William C Russell

Bibliographic Details