Patent ID: 7086225

Claim:
A rotary hydraulic machine having a housing, a rotating group located within said housing and including a plurality of variable capacity chambers defined between pistons slideable within respective cylinders, said pistons being displaceable relative to said cylinders upon rotation of said barrel to vary the volume of said chambers and thereby induce a flow of fluid through said chambers from an inlet port to an outlet port as said rotating group rotates, an adjustment assembly including an actuator operating upon said rotating group to adjust the stroke of said pistons in said cylinder and thereby adjust the capacity of said machine, a fluid supply for said actuator and a control valve interposed between said fluid supply and said actuator to control flow to said actuator, said fluid supply including a pressurized fluid source derived from one of said ports, a hydraulic accumulator to store pressurized fluid from said source and apply stored fluid to said control valve and a check valve between said accumulator and said source to inhibit flow from said accumulator to said source upon reduction of pressure at said source below that of said accumulator whilst maintaining the application of stored fluid to said control valve.