Seat belt retractor with load limiter

• US 20030094533A1
• Filed: 08/14/2002
• Published: 05/22/2003
• Est. Priority Date: 11/20/2001
• Status: Active Grant

• Current Assignee: Key Safety Systems, Inc. (Ningbo Junsheng Investment Group Co., Ltd.)
• Original Assignee: Key Safety Systems, Inc. (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Specht, Martin, Heckmayr, Thomas
• Granted Patent: US 6,719,233 B2
• Time in Patent Office: Days
• US Class Current: 242/379.1
• CPC Class Codes: B60R 2022/282 using fluids or vico-elastic materials
• CPC Class Codes: B60R 2022/284 using electric or magnetic braking means
• CPC Class Codes: B60R 2022/288 with means to adjust or regulate the amount of energy to be absorbed
• CPC Class Codes: B60R 22/3413 operating between belt reel and retractor frame B60R22/4676 takes precedence

Abstract

A seat belt retractor has a belt reel for seat belt webbing and a load limiter that has a flowable load-limiter medium which is transported through a flow channel, by a displacement device. The displacement device is drivable by the belt reel, at an energy consumption related to a crash, in which the flow resistance of the transported load-limiter medium in the flow channel or the volume of the load-limiter medium transported in the flow channel per unit time is adjustable.

Claims

1. A seat belt retractor comprising a belt reel and a load limiter that has a flowable load-limiter medium which is transported through a flow channel by a displacement device drivable by the belt reel, at an energy consumption related to a crash'"'"'s severity, wherein a resistance to the flow of the load-limiter medium in the flow channel or the volume of the load-limiter medium transported in the flow channel per unit time is adjustable.

2. The seat belt retractor of claim 1, wherein the force-limiter medium is transportable by the displacement device from a reservoir space into a collecting space of the load limiter.

3. The seat belt retractor of claim 1 wherein the displacement device is movable in the force-limiter medium that is substantially at rest, with at least part of the force-limiter medium being transported by the moving displacement device.

4. The seat belt retractor of claim 1 wherein the cross-section of the flow channel for the transported force-limiter medium is adjustable in a manner responsive to inertia.

5. The seat belt retractor of claim 2 wherein the cross-section of the flow channel for the transported force-limiter medium is adjustable in a manner responsive to inertia.

6. The seat belt retractor of claim 3 wherein the cross-section of the flow channel for the transported force-limiter medium is adjustable in a manner responsive to inertia.

7. The seat belt retractor of claim 1 wherein the cross-section of the flow channel is adjustable by a servo element acting as an inert mass and acted upon by a restoring force.

8. The seat belt retractor of claim 2 wherein the cross-section of the flow channel is adjustable by a servo element acting as an inert mass and acted upon by a restoring force.

9. The seat belt retractor of claim 3 wherein the cross-section of the flow channel is adjustable by a servo element acting as an inert mass and acted upon by a restoring force.

10. The seat belt retractor of claim 4 wherein the cross-section of the flow channel is adjustable by a servo element acting as an inert mass and acted upon by a restoring force.

11. The seat belt retractor of claim 7 wherein the servo element is movable in the direction of travel.

12. The seat belt retractor of claim 8 wherein the servo element is movable in the direction of travel.

13. The seat belt retractor of claim 9 wherein the servo element is movable in the direction of travel.

14. The seat belt retractor of claim 10 wherein the servo element is movable in the direction of travel.

15. The seat belt retractor of claim 1 wherein the cross-section of the flow channel is adjustable by the mass flow of the transported force-limiter medium.

16. The seat belt retractor of claim15, wherein the cross-section of the flow channel is adjustable by an element around which the transported force-limiter medium flows and which is mounted in opposition to a restoring force.

17. The seat belt retractor of claim 11 wherein the restoring force is a spring.

18. The seat belt retractor of claim 16, wherein the restoring force is a spring.

19. The seat belt retractor of claim 1 wherein the flow resistance or the volume transported per unit time is adjustable by counter-force acting over the entire cross-section of the flow channel.

20. The seat belt retractor of claim 1 wherein the viscosity of the force-limiter medium is adjustable.

21. The seat belt retractor of claim 20 wherein the force-limiter medium is an electro- and/or magneto-rheological fluid having a viscosity that is adjustable by an electrical and/or magnetic field.

22. The seat belt retractor of claim 1 wherein the displacement device is a linearly movable piston.

23. The seat belt retractor of claim 1 wherein the displacement device is a rotor.

24. The seat belt retractor of claim 1 wherein the forces occurring when the belt reel is locked are taken up at least partly by the hydraulic system blocked against transport of the force-limiter medium.

25. The seat belt retractor of claim 24 wherein the locking device of the belt reel is supported at the displacement device.