Patent ID: 7216578

Claim:
A hydraulic actuating device for a movable component of a vehicle, in particular a closure element for closing an opening in a vehicle body, comprising: a hydraulic actuator having a first connection and a second connection, a piston, a first working chamber, which is in communication with the first connection, a second working chamber, which is in communication with the second connection, a pump having a pressure port for delivering a pressurized hydraulic fluid, a reservoir for hydraulic fluid, a first connecting line leading from the pressure port of the pump to the first connection of the hydraulic actuator, a second connecting line leading from the pressure port of the pump to the second connection of the hydraulic actuator, a first control valve assembly, which is located in the first connection line and has a port leading to the first connection, a port leading to the pressure port of the pump and a port leading to the reservoir, a second control valve assembly, which is located in the second connection line and has a port leading to the second connection, a port leading to the pressure port of the pump and a port leading to the reservoir, the second control valve assembly being coupled to a control device for switching the second control valve assembly on command between a first position in which the second connection is connected to the pressure port and a second position, in which the second connection is connected to the reservoir, wherein only the second control valve assembly is coupled to said control device, and wherein the first control valve assembly is provided with hydraulic actuating means, which hydraulic actuating means comprise at least one hydraulic control connection, which is in permanent communication with the second connection of the hydraulic actuator, the hydraulic actuating means being designed to ensure that when a first hydraulic pressure is present at the second connection—which first hydraulic pressure is the consequence of a connection being formed between the second connection and the pressure port—the first connection is connected to the reservoir, and that when a second hydraulic pressure is present at the second connection—which second hydraulic pressure is the consequence of a connection being formed between the second connection and the reservoir—the first connection is connected to the pressure port of the pump.