Patent ID: 7562944

Claim:
A hydraulic machine operable as a variable pressure ratio hydraulic transformer for modifying the pressure, flow rate, or a combination thereof, of fluid flowing through the transformer, the transformer comprising: a housing having at least three housing ports, each of the housing ports being configured to operate as a fluid inlet or as a fluid outlet; a rotor, rotatably disposed within the housing; a plurality of pistons attached to the rotor, each of the pistons including a shaft having a generally spherical end, and a head configured to cooperate with the generally spherical end of the shaft, thereby allowing the head to pivot relative to the shaft; a plurality of cylinders, each of the cylinders being configured to receive a corresponding piston, and having a cylinder axis non-parallel to a corresponding piston shaft; a first plate configured to be rotatably driven by the rotor, and having a first surface configured to contact one end of each of the cylinders and to allow each of the contacting cylinder ends to slide relative to the first surface, the first plate including a plurality of apertures therethrough, at least some of the apertures being configured to facilitate fluid flow to and from the cylinders; and a second plate having at least three plate ports therein, each of the plate ports being configured to cooperate with at least one aperture in the first plate and one housing port, thereby facilitating fluid flow between a housing port and at least one cylinder, the second plate being rotatable relative to the housing ports to modify the transformer pressure ratio.