TEAR STITCHING FOR INFLATABLE VEHICLE OCCUPANT PROTECTION DEVICES

• US 20110140401A1
• Filed: 02/23/2011
• Published: 06/16/2011
• Est. Priority Date: 06/21/2007
• Status: Active Grant

• Current Assignee: TRW Vehicle Safety Systems Incorporated (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Vehicle Safety Systems Incorporated (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Fischer, Kurt F., Gould, Douglas M.
• Granted Patent: US 8,544,883 B2
• Time in Patent Office: Days
• US Class Current: 280/743.1
• CPC Class Codes: B60R 2021/23384 having ends which are movable or detachable during deployment
• CPC Class Codes: B60R 2021/2395 comprising means to control the venting
• CPC Class Codes: B60R 21/233 comprising a plurality of individual compartments; comprising two or more bag-like members, one within the other B60R21/232 takes precedence
• CPC Class Codes: B60R 21/2338 Tethers
• CPC Class Codes: B60R 21/2342 Tear seams
• CPC Class Codes: B60R 21/235 characterised by their material
• CPC Class Codes: B60R 21/239 characterised by their venting means

Abstract

Tear stitching (100) for interconnecting portions (130, 140) of an inflatable vehicle occupant protection device (14) includes first and second end portions (102, 104) having curled configurations and a central portion (110) extending between the end portions. The central portion (110) includes leg portions (112, 114) that converge at an angle and intersect a break point (116). The tear stitching (100) exhibits a comparatively high rupture strength in response to tension forces applied to the interconnected portions (130, 140) that act on the end portions (102, 104) of the tear stitching (100). The tear stitching (100) exhibits a comparatively low rupture strength in response to tension forces applied to the interconnected portions (130, 140) that act on the break point (116) of the tear stitching (100).

Claims

1. Tear stitching for interconnecting portions of an inflatable vehicle occupant protection device, the tear stitching comprising:

a first end portion;

a second end portion; and

a central portion that extends between the end portions, the central portion comprising first and second leg portions that converge at an angle and intersect a break point;

the first end portion extending from the first, leg portion along a path that diverges from the path of the first leg portion;

the second end portion extending from the second leg portion along a path that diverges from the path of the second leg portion;

the tear stitching exhibiting a comparatively high rupture strength in response to tension forces applied to the interconnected portions that act on the end portions of the tear stitching;

the tear stitching exhibiting a comparatively low rupture strength in response to tension forces applied to the interconnected portions that act on the break point of the tear stitching.

2. The tear stitching recited in claim 1, wherein the leg portions of the central portion are arranged in a V-shaped configuration.

3. The tear stitching recited in claim 2, wherein the leg portions are curved convexly away from each other.

4. The tear stitching recited in claim 2, wherein the first and second end portions are curled inward relative to the V-shape of the central portion and toward the break point.

5. The tear stitching recited in claim 4, wherein the end portions are curled inward greater than ninety degrees from their respective interfaces with the central portion.

6. The tear stitching recited in claim 4, wherein the end portions are curled inward greater than one hundred eighty degrees from their respective interfaces with the central portion.

7. The tear stitching recited in claim 4, wherein the end portions are curled inward greater than two hundred seventy degrees from their respective interfaces with the central portion.

8. The tear stitching recited in claim 1, wherein the break point comprises a single stitch, the leg portions extending away from each other and away from the break point.

9. The tear stitching recited in claim 1, wherein the break point comprises a plurality of stitches that are arranged in a line and that extend transverse to the leg portions.

10. The tear stitching recited in claim 1, wherein the break point comprises at most two stitches, the leg portions extending away from each other and away from the break point.

11. The tear stitching recited in claim 1, wherein the portions of the protection device comprise first and second portions of the protection device that are arranged in an overlying manner, the tear stitching extending through and interconnecting the first and second portions, the first portion comprising a first segment of material, the second portion comprising a second segment of material that extends away from the end portions of the tear stitching in a first direction and a third segment of material that extends away from the break point of the tear stitching in a second direction;

the portions of the protection device and the tear stitching being constructed and arranged such that tension applied to the first and second segments creates a shear force that is focused on the end portions, the tear stitching therefore exhibiting a comparatively high rupture strength;

the portions of the protection device and the tear stitching being constructed and arranged such that tension applied to the first and third segments creates a peeling force that is focused on the break point, the tear stitching therefore exhibiting a comparatively low rupture strength.

12. The tear stitching recited in claim 1, further comprising a sacrificial portion that is configured to be subjected to initial tension forces acting on the interconnected portions.

13. The tear stitching recited in claim 12, wherein the tear stitching is configured such that rupture of the sacrificial portion occurs in response to an initial surge in tension between the interconnected portions, the sacrificial portion absorbing the initial surge, the remainder of the tear stitching being subjected to the tension forces after the initial surge subsides and therefore being capable of withstanding the tension forces without rupturing.

14. The tear stitching recited in claim 12, wherein the sacrificial portion is positioned adjacent the break point, the tear stitching being configured such that the sacrificial portion undergoes tension between the portions and ruptures in response to the tension forces prior to the tension forces acting on the break point.

15. The tear stitching recited in claim 12, wherein the sacrificial portion comprises at least one V-shaped portion of stitching nested around the break point.

16. The tear stitching recited in claim 1, wherein the first and second end portions have curled configurations.

17. The tear stitching recited in claim 16, wherein the curled configurations of the first and second end portions are selected such that terminal ends of the first and second end portions are hidden from tension forces applied to the interconnected portions that act on the end portions of the tear stitching.

18. An apparatus for helping to protect an occupant of a vehicle, the apparatus comprising:

an inflatable vehicle occupant protection device having a deflated condition and an inflated condition; and

tear stitching for interconnecting portions of the protection device, the tear stitching comprising;

a first end portion;

a second end portion; and

a central portion extending between the end portions, the central portion comprising leg portions that converge at an angle and intersect a break point;

the first end portion extending from the first leg portion along a path that diverges from the path of the first leg portion;

the second end portion extending from the second leg portion along a path that diverges from the path of the second leg portion;

the tear stitching exhibiting a comparatively high rupture strength in response to tension forces applied to the interconnected portions that act on the end portions of the tear stitching;

the tear stitching exhibiting a comparatively low rupture strength in response to tension forces applied to the interconnected portions that act on the break point of the tear stitching.

19. The tear stitching recited in claim 18, wherein the first and second end portions have curled configurations.

20. The tear stitching recited in claim 19, wherein the curled configurations of the first and second end portions are selected such that terminal ends of the first and second end portions are hidden from tension forces applied to the interconnected portions that act on the end portions of the tear stitching.