Hydraulic pumps and motors of the displacement type

Claim 1

IN A HYDRAULIC POWER UNIT, A SHAFT, AN ECCENTRIC SUPPORTED ON SAID SHAFT, FOUR CYLINDERS RADIALLY DISPOSED ABOUT SAID SHAFT AND SPACED 90* APART, PLUNGERS IN SAID CYLINDERS HAVING REDUCED DIAMETER VALVE PORTIONS INTERMEDIATE THEIR ENDS, THREE VALVE PORTS IN EACH OF SAID CYLINDERS ADAPTED TO COOPERATE WITH SAID VALVE PORTIONS OF THE PLUNGERS, A FLUID PASSAGE CONNECTING THE CENTRAL ONE OF SAID PORTS OF EACH CYLINDER TO THE HEAD OF THE CYLINDER ADJACENT, AN INLET PASSAGE LEADING TO ANOTHER OF SAID PORTS, A DISCHARGE PASSAGE LEADING FROM THE OTHER OF SAID PORTS, SAID ECCENTRIC BEING SO DISPOSED AS TO IMPART BY ITS ROTATION RECIPROCATING MOTION TO SAID PLUNGERS AND SAID VALVE PORTIONS OF THE PLUNGERS BEING THEREBY CAUSED TO CONNECT SAID CENTRAL PORT OF EACH CYLINDER ALTERNATELY TO EACH ADJACENT PORT FOR ALTERNATELY ADMITTING FLUID TO ANOTHER CYLINDER DURING THE INWARD MOTION OF ITS PLUNGER AND ALLOWING DISCHARGE DURING THE OUTWARD MOTION OF ITS PLUNGER, SAID ECCENTRIC BEING CONSTRAINED TO ROTATE WITH SAID SHAFT BUT FREE TO SLIDE TRANSVERSELY THERETO, OPPOSED PISTONS OPERATIVELY INTEGRAL WITH SAID SHAFT, INTERNAL CYLINDERS IN SAID ECCENTRIC COOPERATING WITH SAID PISTON TO FORM OPPOSED CHAMBERS OF VARIABLE BUT COMPLEMENTARY VOLUMES, FLUID PASSAGES LEADING FROM SAID CHAMBERS WHEREBY DIFFERENTIAL PRESSURE MAY BE APPLIED TO CAUSE DISPLACEMENT OF SAID ECCENTRIC, AND A CONTROLLER CONNECTED TO SAID FLUID PASSAGES AND ADAPTED FOR VARYING THE DIFFERENTIAL PRESSURES IN SAID CHAMBERS, SAID CONTROLLER COMPRISING A CYLINDER, A PISTON SLIDABLE IN SAID CYLINDER, TWO CHAMBERS FORMED BY SAID PISTONS IN SAID CYLINDER AND MEANS ADAPTED TO MOVE SAID PISTON WHEREBY THE RELATIVE VOLUMES OF SAID CHAMBERS ARE ALTERED, SAID PASSAGE MEANS CONNECTING EACH OF SAID CYLINDER CHAMBERS WITH ONE OF SAID ECCENTRIC CHAMBERS, WHEREBY MOTION OF SAID PISTON IMPARTS CORRESPONDING MOTION OF SAID ECCENTRIC.