Vane-type variable delivery pump

Claim 1

IN COMBINATION: A CASE PROVIDING A ROTOR AXIS; A ROTOR SHAFT MOUNTED IN SAID CASE FOR ROTATION ABOUT SAID ROTOR AXIS; TWO END PLATES AND A CENTER PLATE MOUNTED IN SAID CASE AND SPACED APART ALONG SAID ROTOR AXIS; TWO RINGS RESPECTIVELY DISPOSED BETWEEN SAID CENTER PLATE AND SAID END PLATES AND RESPECTIVELY HAVING RING AXES PARALLEL TO AND SPACED LATERALLY FROM SAID ROTOR AXIS AND ANGULARLY SPACED APART RELATIVE TO SAID ROTOR AXIS BY 180*, SAID RINGS AND SAID END AND CENTER PLATES COOPERATING TO PROVIDE TWO ROTOR CHAMBERS SEPARATED BY SAID CENTER PLATE, SAID RINGS BEING MOVABLE LATERALLY RELATIVE TO SAID CASE IN DIRECTIONS TO MOVE SAID RING AXES TOWARD AND AWAY FROM SAID ROTOR AXIS; TWO ROTORS OF THE SLIDING VANE TYPE MOUNTED ON SAID ROTOR SHAFT AND RESPECTIVELY OCCUPYING SAID ROTOR CHAMBERS, SAID END PLATES RESPECTIVELY BEING PROVIDED THEREIN WITH INLETS RESPECTIVELY COMMUNICATING WITH SAID ROTOR CHAMBERS AND RESPECTIVELY BEING PROVIDED THEREIN WITH OUTLETS RESPECTIVELY COMMUNICATING WITH SAID ROTOR CHAMBERS, SAID INLETS BEING ANGULARLY SPACED APART RELATIVE TO SAID ROTOR AXIS BY 180* AND SAID OUTLETS BEING ANGULARLY SPACED APART RELATIVE TO SAID ROTOR AXIS BY 180*, WHEREBY LATERAL FORCES RESPECTIVELY APPLIED TO SAID ROTOR SHAFT BY SAID ROTORS ARE 180* OUT OF PHASE RELATIVE TO SAID ROTOR AXIS AND THUS BALANCE EACH OTHER, SAID CENTER PLATE BEING PROVIDED THEREIN WITH DUMMY INLETS RESPECTIVELY COMPLEMENTARY TO AND FACING SAID INLETS IN SAID END PLATES AND BEING PROVIDED THEREIN WITH DUMMY OUTLETS RESPECTIVELY COMPLEMENTARY TO AND FACING SAID OUTLETS IN SAID END PLATES, SAID DUMMY INLETS COMMUNICATING WITH SAID INLETS AND SAID DUMMY OUTLETS COMMUNICATING WITH SAID