Belt Retractor For A Vehicle Safety Belt

• US 20150122931A1
• Filed: 09/04/2014
• Published: 05/07/2015
• Est. Priority Date: 03/07/2012
• 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, Aranda, Guillem, Ferrao, Antonio
• Granted Patent: US 9,650,015 B2
• Time in Patent Office: Days
• US Class Current: 242/379.1
• CPC Class Codes: B60R 2022/285 using friction surfaces
• 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 belt retractor comprising a safety belt reel (1) rotatably mounted on a frame (7) and a load limiter (2) which acts on a rotational movement of the belt reel (1) and has a switchable energy consumption, said load limiter having a granulate (3), which is enclosed in a closed load limiter chamber (8) and consists of dry, granular solid, and at least one rotating member (4) which can be rotated relative to the granulate (3), the energy consumption resulting from shear forces acts between the grains of granulate.

Claims

1. A belt retractor comprising a safety belt reel (1) rotatably mounted on a frame and a load limiter (2) which acts on a rotational movement of the belt reel (1) and has adjustable energy consumption, said load limiter having a granulate (3) which is enclosed in a closed load limiter chamber (8) and consists of dry, granular solid, and at least one rotating member (4), the rotating member (4) and the granulate (3) being arranged so that they are rotatable in relation to each other,

wherein the bulk density of the granulate (3) in the load limiter chamber (8) can be varied to adjust the energy consumption.

2. The belt retractor according to claim 1, wherein the bulk density of the granulate (3) in the load limiter chamber (8) can be adjusted according to the acceleration or speed with which the belt is unreeled under load limitation.

3. The belt retractor according to claim 1, wherein the volume of the load limiter chamber (8) or the pressure exerted on the granulate (3) can be varied in order to adjust the bulk density of the granulate (3) in the load limiter chamber (8).

4. The belt retractor according to claim 1, wherein an actuator member (21;

37) controlled by the load-limited rotation of the belt reel (1) or of a rotatable belt reel part (14) is formed to exert a change of pressure on the granulate (3) disposed in the load limiter chamber (8), or to alter the volume of the load limiter chamber (8).

5. The belt retractor according to claim 4, wherein the actuator member (37) is driven by the load-limited rotation of the belt reel (1) or of the rotatable belt reel part (14).

6. The belt retractor according to claim 4, wherein an adjuster means (34;

39) actuated by load-limited rotation of the belt reel (1) or of the rotatable belt reel part (14) adjusts the actuator member (37).

7. The belt retractor according to claim 6, wherein the adjuster means (34) has an adjuster element (35), which can be adjusted by thread engagement when the belt reel (1) or the rotatable belt reel part (14) rotates under load limitation, and which acts upon the actuator member (37).

8. The belt retractor according to claim 7, wherein the adjuster element (35) is guided along an axial guide (36) and the thread engagement is provided with the axial guide (36) or with the belt reel (1) or the rotatable belt reel part (14).

9. The belt retractor according to claim 1, wherein the adjuster means for the actuator member (37) has a piezoactuator (39) which acts upon the actuator member (37).

10. The belt retractor according to claim 1, wherein the granulate (3) is held stationary when the belt reel (1) or the rotatable belt reel part (14) rotates under load limitation and the rotating member (4) is rotated in relation to the granulate (3), or the rotating member (4) is held in a fixed position and the granulate (3) is rotated in relation to the rotating member (4).

11. The belt retractor according to claim 1, wherein the granulate (3) is made of hard grains.

12. The belt retractor according to claim 1, wherein the grains of the granulate (3) have a Mohs hardness of at least 4.

13. The belt retractor according to claim 1, wherein the granulate (3) comprises different kinds of grains.

14. The belt retractor according to claim 1, wherein the at least one rotating member (4) is submerged wholly or partially in the granulate (3).

15. The belt retractor according to claim 1, wherein the at least one rotating member (4) is embodied as an impeller, the vanes of which are dipped into the granulate (3).

16. The belt retractor according to claim 15, wherein the vanes are curved.

17. The belt retractor according to claim 15, wherein the respective vane has a twist along its extension.

18. The belt retractor according to claim 1, wherein the grains of the granulate (3) are displaced in the radial direction by the rotation.

19. The belt retractor according to claim 1, wherein the granulate (3) is made of hard grains.

20. The belt retractor according to claim 1, wherein the grains of the granulate (3) have a Mohs hardness of at least 4.

21. The belt retractor according to claim 1, wherein the granulate (3) comprises grains with different degrees of hardness.

22. The belt retractor according to claim 1, wherein the granulate (3) consists of mineral grains.

23. The belt retractor according to claim 1, wherein the granulate is made of quartz (SiO₂) sand.

24. The belt retractor according to claim 1, wherein the granulate (3) has grains of glass and/or metal.

25. The belt retractor according to claim 1, wherein the granulate (3) has a bulk density (mass/volume) of between 1 g/cm³ and 4.5 g/cm³.

26. The belt retractor according to claim 1, wherein the load limiter chamber (8) is disposed in the belt reel (1).

27. The belt retractor according to claim 1, wherein the load limiter chamber (8) is disposed in the blockable belt reel part (11) and/or in the rotatable belt reel part (14).

28. The belt retractor according to claim 1, wherein the load limiter chamber (8) is disposed in a housing (9, 10) attached to the frame (7).

29. The belt retractor according to claim 1, wherein the load limiter (2) has a torsion bar (6) in addition.

30. The belt retractor according to claim 1, wherein the torsion bar (6) is connected to a blockable belt reel part (11) and to a belt reel part which is rotatable in relation to the blockable belt reel part (11).

31. The belt retractor according to claim 1, wherein the torsion bar (6) is connected to the rotating member (4) and to the rotatable belt reel part (14).

32. The belt retractor according to claim 31, wherein the torsion bar (6) is also connected to the blockable belt reel part (11) via a break point (17) which is triggered when a force threshold is exceeded.

33. The belt retractor according to claim 1, wherein a slip clutch is provided or formed between the rotating member (4) connected to the torsion bar (6) and the blockable belt reel part (11).

34. The belt retractor according to claim 33, wherein the rotating member (4) is rotatingly connected to the rotatable belt reel part (14) and is mounted rotatably in relation to the torsion bar (6).