Valve for hydraulically operated clutches

Claim 1

A CONTROL VALVE FOR ALTERNATE OPERATION OF A PAIR OF HYDRAULICALLY OPERATED CLUTCHES WHICH REQUIRE LUBRICATION ONLY DURING ENGAGEMENT AND DISENGAGEMENT THEREOF AND WHICH REQUIRE A MINIMUM HYDRAULIC PRESSURE FOR SATISFACTORY OPERATION, COMPRISING: A VALVE BODY HAVING A VALVE BORE FORMED THEREIN, A PRESSURE PORT, A PAIR OF CLUTCH OPERATING PORTS, A PAIR OF CLUTCH LUBRICATING PORTS, SAID PRESSURE PORT CONNECTED THROUGH SAID VALVE BODY INTO SAID VALVE BORE SUBSTANTIALLY LONGITUDINALLY CENTRALLY THEREOF, SAID LUBRICATING PORTS CONNECTED THROUGH SAID VALVE BODY INTO SAID VALVE BORE IN A LONGITUDINAL SPACED RELATIONSHIP ONE ON EACH SIDE OF SAID PRESSURE PORT, EACH OF SAID OPERATING PORTS CONNECTED THROUGH SAID VALVE BODY INTO SAID VALVE BORE BETWEEN SAID PRESSURE PORT AND ONE OF SAID LUBRICATING PORTS, A VALVE SPOOL SLIDABLY CARRIED IN SAID VALVE BORE FOR RECIPROCATING MOVEMENT THEREIN LONGITUDINALLY OF THE VALVE BORE, THREE LANDS FORMED ON SAID VALVE SPOOL IN A SPACED-APART RELATIONSHIP TO EACH OTHER SO THAT ONE LUBRICATING PORT AND ONE OPERATING PORTS ARE POSITIONED BETWEEN THE CENTER LAND AND ONE OF THE OTHER LANDS WHEN SAID CENTER LAND BLOCKS SAID PRESSURE PORT IN THE CENTER NEUTRAL POSITION OF SAID VALVE SPOOL, SAID LANDS BEING SPACED APART SO THAT UPON THE INITIAL MOVEMENT OF SAID VALVE SPOOL IN EITHER DIRECTION FROM SAID CENTER NEUTRAL POSITION SAID PRESSURE PORT IS UNBLOCKED BY SAID CENTER LAND BEFORE ONE OF THE OTHER OF SAID LANDS BLOCK ONE OF SAID LUBRICATING PORTS AND SO THAT FURTHER MOVE-