Granted Patent B2

US 7,555,978 · App. 11/670,124 · Granted Jul 7, 2009

Abstract

Claims (19)

1. Hydraulic actuating device comprising:

a first hydraulic actuator, which actuator has a housing containing a cylinder space in which a piston/piston rod assembly is accommodated in such a way that it can move axially to and fro between corresponding first and second end positions, which piston/piston rod assembly projects out of the housing, in which, in the cylinder space, the piston/piston rod assembly bounds a first chamber and second chamber, which chambers have a volume that depends on the position of the piston/piston rod assembly, the volume of the first chamber being at its smallest when the piston/piston rod assembly is situated in the first end position, and the volume of the second chamber being at its smallest when the piston/piston rod assembly is situated in the second end position, in which the housing is provided with a first and a second connection for the supply and discharge of hydraulic fluid, which connections are in communication with the first and the second chamber, respectively, by way of a first and a second opening, respectively, in the cylinder space,

a second hydraulic actuator, which second actuator has a housing containing a cylinder space in which a piston/piston rod assembly is accommodated in such a way that it can move axially to and fro between corresponding first and second end positions, which piston/piston rod assembly projects out of the housing, in which, in the cylinder space, the piston/piston rod assembly bounds a first chamber and second chamber, which chambers have a volume that depends on the position of the piston/piston rod assembly, the volume of the first chamber being at its smallest when the piston/piston rod assembly is situated in the first end position, and the volume of the second chamber being at its smallest when the piston/piston rod assembly is situated in the second end position, in which the housing is provided with a first and a second connection for the supply and discharge of hydraulic fluid, which connections are in communication with the first and the second chamber, respectively, by way of a first and a second opening, respectively, in the cylinder space,

in which damping means are provided for providing a damping of the speed of movement of a piston/piston rod assembly, wherein

the first opening of the second hydraulic actuator is in communication with the first opening of the first hydraulic actuator;

the second opening of the second hydraulic actuator is in communication with the second opening of the first hydraulic actuator via a third connection to the housing of the first hydraulic actuator, the third connection being in communication with the cylinder space in the first hydraulic actuator via a third opening; and

the damping means are achieved by the fact that the piston/piston rod assembly of the first hydraulic actuator is provided with a throttle means, which, during movement of the piston/piston rod assembly from the first to the second end position, is designed to restrict the outflow of hydraulic fluid via the second opening before the piston/piston rod assembly reaches the second end position,

in which, in addition to the first hydraulic actuator, the second hydraulic actuator is also provided with damping means which are achieved by the fact that the piston/piston rod assembly is provided with a throttle means, which is designed to restrict the outflow of hydraulic fluid via the first opening during movement of the piston/piston rod assembly from the second to the first end position before the piston/piston rod assembly reaches the first end position, and in which the first opening of the second hydraulic actuator is in communication with the first opening of the first hydraulic actuator via a third connection to the housing of the second hydraulic actuator, the third connection being in communication with the cylinder space in the second hydraulic actuator via a third opening.

2. Hydraulic actuating device according to claim 1 , in which the throttle means comprises a throttle element which is fitted in an axially slidable manner on the piston rod of the first hydraulic actuator.

3. Hydraulic actuating device according to claim 1 , in which the throttle means comprises a throttle element which is fitted in an axially slidable manner on the piston rod of the second actuator.

4. Hydraulic actuating device according to claim 2 in which the throttle element has a smaller diameter than the piston.

5. Hydraulic actuating device according to claim 2 in which, when the piston/piston rod assembly movement is moved from one to the other end position, the throttle element comes to lie in a restrictive manner against an opening which is in communication with the connection before the first end position has been reached.

6. Hydraulic actuating device according to claim 2 in which the throttle element is annular.

7. Hydraulic actuating device according to claim 2 in which the throttle element comprises a throttle groove on the head end.

8. Hydraulic actuating device according to claim 2 in which a spring means is provided which presses the throttle element away from the piston.

9. Vehicle, provided with a movable vehicle part which is provided with a hydraulic actuating device according to claim 1 .

10. The vehicle according to claim 9 wherein the moveable vehicle part is a vehicle part for closing an opening in a vehicle body.

11. The vehicle according to claim 10 wherein the vehicle part for closing the opening in the vehicle body is a moveable roof.

12. The vehicle according to claim 11 wherein the moveable roof is at least one of a folding roof and a retractable hard top.

Assignments (11)