Hydraulic pump or motor

Claim 1

IN A HYDRAULIC PUMP COMPRISED OF A HOUSING HAVING A SHAFT OPENING, A SHAFT EXTENDING THROUGH SAID OPENING AND ROTATABLY SUPPORTED IN SAID HOUSING, A PLURALITY OF CHAMBER FORMING MEMBERS ROTATABLE WITH SAID SHAFT AND DEFINING A PLURALITY OF AXIALLY OPEN ENDED CHAMBERS WHICH PROGRESSIVELY INCREASE AND DECREASE IN VOLUME AS SAID SHAFT ROTATES TO TAKE IN AND DISCHARGE HYDRAULIC FLUID, AT LEAST ONE OF SAID CHAMBERS BEING AT HIGH PRESSURE, MEANS COMMUNICATING THE HIGH PRESSURE TO THE INSIDE OF SAID HOUSIING, THE IMPROVEMENT WHICH COMPRISES A SEALING MEMBER ROTABLE WITH SAID SHAFT AND BEING AXIALLY MOVABLE RELATIVE TO SAID CHAMBER FORMING MEMBERS, SAID SEALING MEMBER HAVING A FIRST AXIALLY FACING SURFACE IN SEALING ENGAGEMENT WITH AN AXIAL END OF SAID CHAMBER FORMING MEMBERS TO SEALINGLY CLOSE THE ENDS OF SAID CHAMBERS AND ALSO HAVING AT LEAST A SECOND OPPOSITE AXIALLY FACING SURFACE FACING TOWARD SAID SHAFT OPENING AND EXPOSED TO THE HIGH PRESSURES, A SEALING RING SURROUNDING SAID SHAFT AND HAVING A FIRST AXIALLY FACING SURFACE IN ENGAGEMENT WITH SAID SEALING MEMBER SECOND SURFACE, SAID SEALING RING ALSO HAVING A SECOND OPPOSITE AXIALLY FACING SURFACE ALSO EXPOSED TO SAID HIGH PRESSURES TO CREATE A FORCE URGING SAID FIRST SEALING RING SURFACE INTO ENGAGEMENT WITH SAID SECOND SEALING MEMBER SURFACE.