Linear actuator with an internal dampening mechanism

• US 6,942,261 B2
• Filed: 08/14/2003
• Issued: 09/13/2005
• Est. Priority Date: 08/14/2003
• Status: Expired due to Fees

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Original Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Inventors: Smith, Bradley W., Larsen, Alan R., Lindsey, David W.
• Primary Examiner(s): Engle, Patricia L.
• Application Number:
  US10/640,845
• Publication Number:
  US 20050035608A1
• Time in Patent Office: 761 Days
• Field of Search: 293/107, 293/108, 293/118, 293/116, 293/117, 280/274, 280/730.1, 280/770, 606/32, 606/36, 606/37, 606/38, 277/917, 277/928, 180/274
• US Class Current: 293/107
• CPC Class Codes: B60R 19/32 Fluid shock absorbers , e.g. with coaxial coil springs
• CPC Class Codes: F15B 15/19 Pyrotechnical actuators

Abstract

A linear actuator with an internal dampening mechanism is disclosed. The actuator has a housing has a first end and a second end and forms an internal chamber. A constricted opening is also added to the actuator at the first end. A piston is disposed within the housing and is capable of sliding along the chamber. The piston has a head portion and a shaft portion. The shaft portion is slidable through the constricted opening whereas the head portion is not slidable through the constricted opening. A fluid is also added to the actuator. The fluid is disposed within the housing. In one embodiment, the actuator is constructed such that the sliding of the shaft portion forces a fluid through the constricted opening such that the movement of the piston is dampened. In an alternative embodiment, the actuator includes one or more second pistons and an orifice. In this embodiment, the actuator is constructed such that the sliding of the piston forces the fluid through the orifice and causes the second pistons to telescopically extend from the first piston.

Claims

1. A linear actuator comprising:

a housing having a first end and a second end, the housing defining an internal chamber;

a constricted opening disposed at the first end;

a piston being disposed within the housing, the piston having a shaft portion and a head portion, the shaft portion being constructed such that it is slidable through the constricted opening and the head portion being constructed such that it is not slidable through the constricted opening; and

a fluid disposed within said internal chamber such that when the piston slides in the direction of the constricted opening, the fluid is forced through the constricted opening such that the movement of the piston is dampened.

2. An actuator as in claim 1 further comprising a displacement mechanism that is capable of causing the shaft portion to slide through the constricted opening.

3. An actuator as in claim 2 wherein the displacement mechanism comprises a gas generant in communication with an initiator.

4. An actuator as in claim 3 further comprising a one or more barrier foils.

5. An actuator as in claim 3 wherein the initiator is capable of igniting the gas generant.

6. An actuator as in claim 1 further comprising one or more blowout seals that cover the constricted opening.

7. An actuator as in claim 6 wherein the sliding of the piston towards the constricted opening operates to remove the one or more blowout seals.

8. An actuator as in claim 1 further comprising one or more piston seals.

9. An actuator as in claim 1 further comprising one or more pin joints positioned on the exterior of the actuator.

10. An actuator as in claim 9 wherein the one or more pin joints are used to mount the actuator to a vehicle on or proximate to the vehicle'"'"'s bumper.

11. An actuator as in claim 1 wherein the actuator is used to deploy a reactive member.

12. An actuator as in claim 11 wherein the reactive member comprises a deformable plate.

13. An actuator as in claim 11 wherein the reactive member is designed to support an inflated bumper airbag.

14. An actuator as in claim 11 wherein the reactive member comprises all or a portion of the vehicle'"'"'s bumper.

15. An actuator as in claim 1 wherein the shaft portion is attached to an extending arm.

16. An actuator as in claim 1 wherein the actuator has been constructed such that the amount of fluid forced through the constricted opening varies with the movement of the piston.

17. An actuator as in claim 1 wherein the shaft portion is tapered.

18. A linear actuator designed to deploy a reactive member, the actuator comprising:

a housing having a first end and a second end, the housing defining an internal chamber;

a constricted opening disposed at the first end;

a piston being disposed within the housing, the piston having a shaft portion and a head portion, the shaft portion being constructed such that it is slidable through the constricted opening and the head portion being constructed such that it is not slidable through the constricted opening;

a displacement mechanism capable of causing the shaft portion to slide through the constricted opening; and

a fluid disposed within said internal chamber such that when the piston slides in the direction of the constricted opening, the fluid is forced through the constricted opening such that the movement of the piston is dampened.

19. An actuator as in claim 18 wherein the displacement mechanism comprises a gas generant in communication with an initiator.

20. An actuator as in claim 18 further comprising one or more blowout seals covering the constricted opening, wherein the actuator is constructed such that the sliding of the piston towards the constricted opening is configured to remove one or more blowout seals.

21. An actuator as in claim 18 wherein, the actuator has been constructed such that the amount of fluid that may be forced through the constricted opening varies with the movement of the piston.

22. An actuator as in claim 18 wherein the reactive member comprises a deformable plate.

23. An actuator as in claim 18 wherein the reactive member is designed to support an inflated bumper airbag.

24. An actuator as in claim 18 wherein the reactive member comprises all or a portion of the vehicle'"'"'s bumper.

25. A method for using a linear actuator to deploy a reactive member comprising:

attaching the reactive member to the vehicle;

mounting a linear actuator onto the vehicle proximate the reactive member, the linear actuator comprising a housing having a first end and a second end, the housing defining an internal chamber, a constricted opening disposed at the first end, a piston being disposed within the housing, the piston having a shaft portion and a head portion, the shaft portion being constructed such that it is slidable through the constricted opening and the head portion being constructed such that it is not slidable through the constricted opening, and a fluid disposed within said internal chamber such that when the piston slides in the direction of the constricted opening, the fluid is forced through the constricted opening such that the movement of the piston is dampened; and

configuring the linear actuator such that the sliding of the shaft portion through the constricted opening deploys the reactive member.

26. A method as in claim 25 wherein the configuring step comprises sliding of the shaft portion through the constricted opening deploys the reactive member downwards into a position capable of providing support or impact protection to the vehicle.

27. A method as in claim 25 wherein the reactive member comprises a deformable plate.

28. A method as in claim 25 wherein the reactive member comprises all or a portion of a vehicle bumper.

29. A method as in claim 25 wherein the reactive member is designed to support an inflated bumper airbag.