Abstract: A fluid pressure actuator is disclosed of the type such as a hydraulic cylinder, having an arrangement for sensing the position of the piston and operating rod assembly at points within the cylinder. The sensing arrangement is disclosed as a magnetically biased reed switch which is installed within the cylinder pressure chamber so as to sense the proximity of the piston or a portion of the attached operating rod. Operating circuitry associated with each proximity switch is also disclosed which provides a delay feature preventing triggering of the associated circuitry upon momentary closing of the reed switch contacts due to mechanical vibrations or other causes.

Abstract: A snap action fluid pressure actuated switch, including a switch housing within which is mounted a metallic dome-shaped disc which is dimpled in its center by a predetermined pressure differential to provide a snap action, while being biased to eliminate the deformation and return the switch after the pressure differential declines. The disc is secured to a spool contact movably by the snap action of the disc into and out of electrical contact with either of a pair of contact plates to create an electrical connection between a terminal electrically connected to the metallic disc and either of a pair of terminals connected to a respective contact plate. The free end of the spool contact is piloted at its free end and adjustable fixed stops are provided to position the spool contact in the connected metallic disc at either end point of the snap action movement, while enabling adjustability in the end positions of the spool contact and the pressure conditions causing the snap action to occur.

Abstract: A control device includes a magnetically actuated responder and an actuator. The responder is fixed to a relatively stationary portion of an apparatus and the actuator is fixed to a portion of the apparatus which is movable relative to the fixed portion. The fixed portion includes a housing for constraining the second, movable portion to linear movement. The actuator is located so that its outer surface is recessed into the surface of the movable portion flush with the surface of the movable portion of the apparatus thus providing an actuator for the responder which does not interfere with the movement of the movable portion. An alternate embodiment contemplates the use of a plurality of flush-mounted actuators axially spaced along the movable member with each actuator occupying only a portion of the circumference of the movable portion.