Valve operator

Claim 1

A VALVE OPERATOR COMPRISING A MAIN HOUSING ADAPTED TO BE MOUNTED ON THE BODY OF A VALVE HAVING A PROTRUDING VALVE STEM END, SAID HOUSING HAVING A CHAMBER SURROUNDING SAID PROTRUDING VALVE STEM END; VALVE ACTUATING MECHANISM INCLUDING A REVERSIBLE MOTOR, WORM PINION SHAFT MEANS DRIVEN BY SAID MOTOR, A WORM GEAR JOURNALED IN SAID HOUSING AND MESHINGLY ENGAGED WITH SAID DRIVEN BY SAID WORM PINION SHAFT MEANS, A DRIVEN SHAFT DRIVINGLY COUPLED TO SAD WORM GEAR THROUGH INTERMESHING AXIALLY DIRECTED HELICAL SPLINES WHEREBY RELATIVE AXIAL MOVEMENT BETWEEN SAID WORM GEAR AND DRIVEN SHAFT IS PERMITTED IN EITHER DIRECTION IN RESPONSE TO TORQUE THRUST FORCES DEVELOPED WHEN SAID WORM GEAR DRIVES SAID DRIVEN SHAFT IN SELECTED DIRECTION, MEANS YIELDINGLY SUPPORTING ONE END OF SAID DRIVEN SHAFT FOR OPPOSITE AXIAL AND ROTATIONAL MOVEMENT WITH RESPECT TO SAID MAIN HOUSING TO ESTABLISH A PREDETERMINED RESISTANCE TO SAID RELATIVE AXIAL MOVEMENT BETWEEN SAID WORM GEAR AND DRIVEN SHAFT AND MEANS SLIDABLY AND NON-ROTATABLY COUPLING THE OTHER END OF SAID DRIVEN SHAFT TO THE PROTRUDING VALVE STEM END; AND MOTOR CONTROL MEANS COMPRISING CUT OUT SWITCHES OPERATIVELY CONNECTED TO SAID DRIVEN SHAFT FOR DISRUPTING MOTOR OPERATION IN RESPONSE TO AXIAL MOVEMENT OF SAID DRIVEN SHAFT IN EITHER DIRECTION RELATIVE TO SAID WORM GEAR WHEN SAID PREDETERMINED RESISTANCE IS EXCEEDED, POSITION LIMIT SWITCHES OPERATIVELY CONNECTED TO SAID WORM PINION SHAFT FOR ACTUATION THEREBY TO ESTABLISH RESPECTIVE OPPOSITE DIRECTIONAL MOTOR DRIVE CIRCUTS WHEN SAID VALVE OPERATOR REACHES ITS OPPOSITE LIMIT POSITIONS, AND MANUAL SWITCH MEANS SELECTIVELY OPERABLE TO ENERGIZE SAID RESPECTIVE OPPOSITE DIRECTIONAL MOTOR DRIVE CIRCUITS ESTABLISHED BY SAID POSITION LIMIT SWITCHES.