Hydraulic pump

Claim 1

IN A FLUID PUMP, A HOUSING, CAM MEANS IN SAID HOUSING DEFINING A PUMP CAVITY, SAID HOUSING A PAIR OF COAXIAL OPENINGS SPACED BY AND COMMUNICATING WITH SAID CAVITY, INLET AND OUTLETS PORTS COMMUNICATING WITH SAID CAVITY TO SUPPLY FLUID THERETO AND TO DISCHARGE FLUID THEREFROM RESPECTIVELY, A ROTOR SHAFT HAVING OPPOSITELY DIRECTED END PORTIONS EXTENDING COAXIALLY INTO SAID OPENINGS RESPECTIVELY, PUMPING MEANS CARRIED BY SAID ROTOR SHAFT IN SAID CAVITY FOR PUMPING SAID FLUID FROM SAID INLET PORT TO SAID DISCHARGE PORT, MEANS PROVIDING A BEARING SUPPORT FOR ONE OF SAID ROTOR END PORTIONS WITHIN ONE OF SAID OPENINGS, A PRESSURE PLATE SLIDABLE AXIALLY WITHIN THE OTHER OF SAID OPENINGS, AN OUTER CLOSURE MEMBER FOR SAID OTHER OPENING AND COOPERATING THEREWITH TO DEFINE A DISCHARGE SURE PLATE AND COOPERATING THEREWITH TO DEFINE A DISCHARGE HEADER THEREBETWEEN, MEANS CONNECTING THE FLUID PRESSURE AT SAID DISCHARGE PORT WITH SAID DISCHARGE HEADER TO URGE SAID AXIALLY SLIDABLE PRESSURE PLATE TOWARD SAID PUMPING MEANS AND AGAINST SAID CAM MEANS WITH A FORCE PROPORTIONAL TO THE DISCHARGE PRESSURE OF SAID PUMP, AND MEANS SUPPORTING THE OTHER OF SAID ROTOR END PORTIONS AND SEALING THE LATTER FROM THE PRESSURE IN SAID DISCHARGE HEADER COMPRISING A CENTRAL CUP-SHAPED PORTION OF SAID PRESSURE PLATE PROVIDING A RECESS OPENING TOWARD SAID CAVITY AND HAVING SAID OTHER ROTOR END PORTION JOURNALED THEREIN, THE LAST NAMED MEANS ALSO COMPRISING CONFRONTING ANNULAR SEALING PORTIONS OF SAID PRESSURE PLATE AND PUMPING MEANS AROUND SAID RECESS AND MATING TO EFFECT A HIGH RESISTANCE FLUID LEAKAGE PATH THEREBETWEEN INTO SAID RECESS.