Seat belt retractor with load limiter

• US 6,719,233 B2
• Filed: 08/14/2002
• Issued: 04/13/2004
• Est. Priority Date: 11/20/2001
• Status: Expired due to Fees

• 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
• Primary Examiner(s): Jillions, John M.
• Application Number:
  US10/217,416
• Publication Number:
  US 20030094533A1
• Time in Patent Office: 608 Days
• Field of Search: 242/379.1, 242/381, 280/805, 280/806, 297/470, 297/471, 297/472, 188/267.1, 188/267.2, 188/275, 188/280
• 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 by adjusting the cross-section of the flow channel using a servo element acting as an inert mass and acted upon by a restoring force.

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 servo element is movable in a direction of travel.

8. The seat belt retractor of claim 2 wherein the servo element is movable in a direction of travel.

9. The seat belt retractor of claim 3 wherein the servo element is movable in a direction of travel.

10. The seat belt retractor of claim 4 wherein the servo element is movable in a direction of travel.

11. The seat belt retractor of claim 7 wherein the restoring force is a spring.

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

13. The seat belt retractor of claim 12 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.

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

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

16. 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, and 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.

17. 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, and the forces occurring when the belt reel is locked are taken up at least partly by a hydraulic system blocked against transport of the force-limiter medium.

18. The seat belt retractor of claim 17 wherein the locking device of the belt reel is supported at the displacement device.