Vehicle suspension with a dock height holding device

• US 6,786,509 B2
• Filed: 11/06/2001
• Issued: 09/07/2004
• Est. Priority Date: 11/06/2001
• Status: Expired due to Fees

• Current Assignee: ArvinMeritor Technology LLC (Meritor, Inc. (Nevada))
• Original Assignee: Meritor Heavy Vehicle Technology, LLC
• Inventors: Lang, Kenneth G., Miller, Steven R., Eckelberry, James, Clisch, Richard M.
• Primary Examiner(s): Ilan, Ruth
• Application Number:
  US09/992,496
• Publication Number:
  US 20030085536A1
• Time in Patent Office: 1,036 Days
• Field of Search: 280/6.151, 280/6.153, 280/124.158, 280/754, 280/755, 267/64.12, 267/122, 267/218, 188/269
• US Class Current: 280/754
• CPC Class Codes: B60G 17/005 Suspension locking arrangements for retractable wheels B62D61/12
• CPC Class Codes: B60G 17/052 Pneumatic spring characteristics B60G17/048 takes precedence ; valves per se F16K

Abstract

A vehicle suspension assembly includes a height holding device that is at least partially supported within an air spring of the suspension assembly. The height holding device includes a hydraulic ram. A moveable portion of the hydraulic ram moves between a first position where a minimum clearance is maintained between suspension components and a second position where a larger clearance is maintained between the suspension components. The height holding device moves into the second position to maintain a desired height of the truck or trailer bed during loading and unloading operations at a loading dock, for example. The height holding device allows for the suspension air springs to be evacuated of air pressure during loading or unloading conditions without a change in deck height.

Claims

1. A vehicle suspension assembly, comprising:

a first support member attachable to a body of the vehicle;

a second support member that moves relative to the first support member;

at least one air spring coupled with the first and second support members;

a height holding device at least partially within the air spring and supported on one of the first and second support members, the height holding device having a moveable portion that is moveable from a first retracted position where the moveable portion permits relative movement between the first and second support members into a second extended position where the moveable portion maintains a desired spacing between the first and second support members;

a biasing member that biases the moveable portion into the first retracted position;

a hydraulic ram that moves the moveable portion against the bias of the biasing member, the moveable portion comprising a piston portion of the hydraulic ram; and

an inlet port associated with the hydraulic ram that selectively locks the hydraulic ram such that pressure within the hydraulic ram provides the only maintaining force to maintain the moveable portion in the second extended position.

2. The assembly of claim 1, including an actuator that controls the inlet port to thereby control movement of the piston portion.

3. The assembly of claim 2, wherein the actuator moves the piston portion into the second extended position responsive to an application of the vehicle parking brake.

4. The assembly of claim 1, wherein the moveable portion is moved with a force that is too small to cause an increase in a spacing between the first and second support members.

5. The assembly of claim 1, including a bead plate within the air spring that is associated with the first support member and a retainer plate that is associated with the second support member and wherein the height holding device is at least partially supported on one of the retainer plate or the bead plate.

6. The assembly of claim 5, wherein the height holding device is supported on the bead plate.

7. The assembly of claim 5, including a bumper member supported on an end of the moveable portion that contacts the other of the bead plate or the retainer plate when the moveable portion moves into a position to maintain the desired spacing between the first and second support members.

8. The assembly of claim 1, wherein the biasing member comprises a spring.

9. The assembly of claim 1, including

a controller that determines when air pressure from within the air spring will be evacuated and the controller causes the moveable portion to move into the second extended position to maintain a current spacing between the first and second support members before the air spring pressure is evacuated.

16. The assembly of claim 1, wherein the height holding device includes a stationary portion that is received within the air spring and the moveable portion is moveable relative to the stationary portion and including at least one seal between the stationary portion and an associated portion of the air spring, the seal preventing air from exiting the air spring.

17. The assembly of claim 16, including a shaft portion of the hydraulic ram outside of the air spring and a second seal at an interface between the shaft portion and an associated portion of the air spring, the second seal preventing air from exiting the air spring.

18. The assembly of claim 16, wherein the stationary portion is welded to the associated portion of the air spring.

10. An air spring assembly for use in a vehicle suspension system, comprising:

a bead plate supported on a portion of the suspension system that remains stationary relative to the vehicle body;

a retainer plate supported on a portion of the suspension system that is moveable relative to the stationary portion;

a bellows that extends between the bead plate and the retainer plate, the bellows containing a selected air pressure to provide a desired amount of damping of movement of the moveable suspension portion relative to the stationary portion;

a height holding device at least partially within the bellows and at least partially supported on one of the bead plate or the retainer plate, the height holding device having a moveable portion that is moveable from a first retracted position where there is clearance between the moveable portion and the other of the bead plate or the retainer plate and a second extended position where the moveable portion contacts the other of the bead plate or the retainer plate;

a biasing member that biases the moveable portion into the first retracted position;

a hydraulic ram that moves the moveable portion against the bias of the biasing member into the second extended position; and

an inlet port associated with the hydraulic ram that selectively locks the hydraulic ram such that pressure within the hydraulic ram provides the only maintaining force to maintain the moveable portion in the second extended position.

11. The assembly of claim 10, wherein the height holding device is at least partially supported on the bead plate.

12. The assembly of claim 10, wherein the moveable portion comprises a piston portion of the hydraulic ram.

13. The assembly of claim 12, including an actuator that controls the inlet port to thereby control movement of the piston portion.

14. The assembly of claim 13, wherein the actuator is operative to move the piston portion into the second extended position responsive to an application of the vehicle parking brake.

15. The assembly of claim 10, including a bumper member supported on an end of the moveable portion that contacts the other of the bead plate or the retainer plate when the moveable portion moves into the second extended position.

19. The assembly of claim 10 wherein the height holding device includes a stationary portion that is received within the air spring and the moveable portion is moveable relative to the stationary portion and including at least one seal between the stationary portion and an associated portion of the air spring, the seal preventing air from exiting the air spring.

20. The assembly of claim 19, including a shaft portion of the hydraulic ram outside of the air spring and a second seal at an interface between the shaft portion and an associated portion of the air spring, the second seal preventing air from exiting the air spring.

21. The assembly of claim 19, wherein the stationary portion is welded to the associated portion of the air spring.