Patent ID: 7647858

Claim:
A differential piston ( 1 ) having a first section ( 2 ), extending substantially perpendicular to a direction (B) of motion of the differential piston ( 1 ), and a second section ( 3 ), extending substantially in the direction (B) of motion of the differential piston ( 1 ), the second section ( 3 ) of the differential piston ( 1 ) being radially located within the first section ( 2 ) of the differential piston ( 1 ), and the first section ( 2 ) of the differential piston ( 1 ) having a first effective piston surface ( 4 ), on a first side ( 5 ) thereof, and a second effective piston surface ( 6 ) on a second side thereof, the first effective piston surface ( 4 ) being associated with a first pressure chamber ( 8 ) and the second effective piston surface ( 6 ) being associated with a second pressure chamber ( 9 ), a pressurized working fluid being supplied to the first and the second pressure chambers, via at least one fluid channel ( 10 , 11 , 12 ), at least one of the first pressure chamber ( 8 ) and the second pressure chamber ( 9 ) being delimited by at least some areas of the second section ( 3 ) extending substantially in the direction (B) of displacement, and the differential piston ( 1 ) having a pressure medium-guiding channel ( 13 ), in communication with the at least one fluid channel ( 10 , 11 , 12 ) and extending to at least one of the pressure chambers ( 8 , 9 ); and the pressure medium-guiding channel ( 13 ) is arranged at least partially inside the first section ( 2 ) of the differential piston ( 1 ) which extends substantially perpendicular to the direction (B) of displacement of the differential piston ( 1 ).