Patent ID: 7017679

Claim:
A device for the continuous unbalanced adjustment of a steerable vibration plate, comprising: two adjustable unbalanced masses mounted on a common shaft of the steerable vibration plate, a storage unit for hydraulic fluid, and a pressure source comprising a delivery pump for the hydraulic fluid, wherein to each of the adjustable unbalanced masses there is allocated a double-acting hydraulic cylinder having two fluid chambers, and a piston that separates the fluid chambers from one another, the piston of each cylinder is operatively connected to the unbalanced mass allocated thereto, and wherein for the displacement of the piston, one of the fluid chambers of each cylinder is selectively in fluid connection with the delivery pump and at the same time the other of the fluid chambers is selectively in fluid connection with the storage unit, and wherein, in order to fix the piston in its position, both fluid chambers are selectively sealed simultaneously from fluid connection to both the storage unit and the delivery pump.