Patent ID: 8439004

Claim:
A ball-lift device with screw for a variable compression ratio engine comprising: a hydraulic double-acting control actuator ( 8 ) comprising an upper chamber ( 121 ) and a lower chamber ( 122 ) and at least one actuator piston ( 13 ) connected to a control rack ( 7 ); at least two balls ( 401 , 402 ) or valve elements each resting on a seat ( 403 , 404 ) and closing off respectively one and the other end of a transfer channel ( 405 ) connecting the upper chamber ( 121 ) and the lower chamber ( 122 ) of the control actuator ( 8 ), said balls ( 401 , 402 ) acting as a nonreturn valve element when they are held on their seat ( 403 , 404 ) by a spring ( 408 , 409 ) in order to allow hydraulic fluid to pass in only one direction; and lifting means ( 410 ) comprising at least one electric motor ( 480 ) designed to rotate at least one screw ( 481 , 482 ) making it possible to lift from or place on a seat ( 403 , 404 ) of the lifting means ( 410 ) at least one ball ( 401 , 402 ).