Abstract: An automated machining center performs various operations on a work piece which is locked onto the pallet using a hydraulically operable fixture. An automatic coupling system according to the invention provides for automatic coupling between the pallet and a source of hydraulic power to selectively lock or release the work piece on the pallet. The coupling system includes a cam ring associated with the pallet in axial alignment with a rotatable locking rod associated with a base unit. The locking rod is axially mounted to a dual acting hydraulic cylinder itself axially mounted to a carriage which is moveable relative to the base unit. Alternate extension and retraction of the cylinder causes the locking rod to selectively engage the cam ring to draw the carriage towards the pallet to provide automatic coupling between quick coupler sockets on the carriage and quick plug couplers on the pallet to provide a fluid communication line between a source of power and the hydraulic fixture.

Abstract: A switch operating mechanism associated with a motor driven hydrostatic system operative in forward or reverse directions with respect to a neutral inoperative state, for rendering a motor starting circuit operative only when the hydrostatic system is in its neutral state. An axially movable switch operating shaft has a notch therein which receives a detent on the control stem of the switch, only when the shaft is in a position generally centrally between opposite limits of its axial movement, to close the switch. A centering spring urges the shaft toward its centrally disposed position.