Film advancing mechanism for photographic projectors

Claim 1

FILM ADVANCING MECHANISM FOR DRIVING A FILM STRIP ONE FRAME AT A TIME THROUGH THE GATE OF A PHOTOGRAPHIC PROJECTOR COMPRISING AN ELECTRIC MOTOR, MEANS FOR CLOSING AN ELECTRIC CIRCUIT TO SAID MOTOR, A RECIPROCATORY MEMBER, A ROTARY FILM SPROCKET FOR ENGAGING AND FEEDING FILM, MEANS INCLUDING A RATCHET AND PAWL MECHANISM FOR ROTATING SAID SPROCKET ON EACH STROKE OF SAID MEMBER IN ONE DIRECTION TO ADVANCE SAID SPROCKET STEP-BY-STEP UPON SUCCESSIVE MOVEMENTS OF SAID MEMBER IN SAID ONE DIRECTION, MEANS CONNECTING SAID MOTOR TO SAID MEMBER TO MOVE SAID MEMBER IN SAID ONE DIRECTION WHEN AN ELECTRIC CIRCUIT IS CLOSED TO SAID MOTOR, SPRING MEANS CONNECTED TO SAID MEMBER TO URGE SAID MEMBER CONSTANTLY IN THE OPPOSITE DIRECTION TO RETURN SAID MEMBER TO ITS STARTING POSITION AND TO TURN SAID MOTOR BACKWARDS, AN ELEMENT CONNECTED TO SAID MOTOR TO BE DRIVEN THEREBY DURING OPERATIN OF SAID MOTOR, AND MEANS CARRIED BY SAID MEMBER AND OPERATIVE AT THE LIMIT OF MOVEMENT OF SAID MEMBER IN SAID ONE DIRECTION TO ENGAGE SAID ELEMENT TO STOP ROTATION OF THE SAME AND TO STALL SAID MOTOR.