Patent ID: 8597002

Claim:
A hydraulic machine comprising: a body having a chamber; an inlet for introducing hydraulic fluid into the chamber; an outlet through which hydraulic fluid leaves the chamber; a rotor rotatably mounted within the chamber; the chamber and the rotor being shaped to define one or more rise regions, fall regions and dwell regions between walls of the chamber and the rotor; a shaft extending from the rotor; the rotor having a plurality of slots; a plurality of vanes located such that each slot of the rotor has a vane located therein, each vane being movable between a retracted position and an extended position wherein in the retracted position, the vane not working the hydraulic fluid introduced into the chamber and in the extended position the vane working the hydraulic fluid introduced into the chamber; vane retaining means being selectively actuable such that, when actuated, the vane retaining means retains the vanes in the retracted position, said vane retaining means being arranged such that a first pressurized hydraulic fluid circuit is for actuating the vane retaining means to retain the vanes in the retracted position and for deactivating the vane retaining means such that the vanes move from the retracted position to the extended position; and under vane passages, including at least one passage per vane to drain fluid from under the vane when the vane moves from the extended position to the retracted position and to be placed in fluid communication with the outlet to communicate pressurized fluid to the vane to extract the vane, the under vane passages comprising a second hydraulic fluid circuit, separate from the first pressurized hydraulic fluid circuit, wherein the rotor comprises a first rotor part joined to a second rotor part, one or both of the first rotor part and the second rotor part defining fluid flow passages for providing pressurized hydraulic fluid to the vane retaining means, one or both of the first rotor part and the second rotor part defining vane retaining means movement passages, said vane retaining means being located in said vane retaining means movement passages wherein said vane retaining means move in said vane means movement passages between a retaining position and a non-retaining position.