Patent ID: 6116139
Filing Date: 2000-09-12
Classification: F15B

Abstract:
Control apparatus for a linear actuator having an extensible member, an air operated apparatus including a cylinder extending and retracting a piston for moving an external load, and an elongated threaded lead screw carried in alignment in said cylinder and driven by an electric motor for positioning the load comprising:a valve housing positioned between said electric motor and said cylinder for selectively distributing air under pressure to an extend side of said cylinder and to a retract side of said cylinder;a valve spool in said valve housing connectable on one end to and in alignment with said elongated threaded lead screw and on the other end to and in alignment with said electric motor for controlling said selectively distributing air;an assembly for moving said valve spool toward said electric motor responsive to rotation of said elongated threaded member in one direction and toward said cylinder responsive to rotation of said elongated threaded member in the other direction anda coupling connecting the other end of said valve spool to the electric motor permitting said moving of said valve spool and driving said elongated threaded lead screw for said rotation.