INFLATABLE KNEE AIRBAG HAVING TWO CHAMBERS SEPARATED BY AN INTERNAL TETHER

• US 20110012327A1
• Filed: 07/16/2009
• Published: 01/20/2011
• Est. Priority Date: 07/16/2009
• Status: Active Grant

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Original Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Inventors: Enders, Mark L.
• Granted Patent: US 8,297,649 B2
• Time in Patent Office: Days
• US Class Current: 280/730.1
• CPC Class Codes: B60R 2021/23169 specially adapted for knee protection
• CPC Class Codes: B60R 2021/23324 Inner walls crating separate compartments, e.g. communicating with vents
• CPC Class Codes: B60R 21/231 characterised by their shape, construction or spatial configuration
• CPC Class Codes: B60R 21/2334 Expansion control features

Abstract

Inflatable airbag cushions can be formed with one or more inflatable chambers, each having different inflated widths and volumes. For example, an inflatable knee airbag can have a first chamber that is adjacent to the periphery of the airbag and a second chamber that is nested within the first chamber. The two chambers can be fluidly coupled and the second chamber may have a vent formed in it that can release inflation gas out of the airbag. The airbag may have more than one nested chamber. The nested chambers can be defined by one or more internal tethers that can be formed from one or more pieces of material. The airbag can be configured such that it and any internal tethers are produced from a single panel of material.

Claims

1. An inflatable knee airbag comprising:

an airbag cushion comprising a plurality of inflatable chambers,

wherein one of the inflatable chambers is nested within an outer inflatable chamber,

wherein the airbag cushion has an upper portion and a lower portion,

wherein the nested inflatable chamber is partially defined by an internal tether, and

wherein during inflation, the airbag cushion is configured to receive inflation gas from an inflator and to direct the inflation gas such that the inflation gas is split by a lower side of the nested inflatable chamber such that the inflation gas travels around the nested inflatable chamber to a periphery of the outer inflatable chamber and then converges on an upper side of the nested inflatable chamber.

3. The inflatable knee airbag of claim 1, wherein during inflation, the outer inflatable chamber is partially inflated before the inflation gas enters the nested inflatable chamber.

4. The inflatable knee airbag of claim 3, wherein the inflation gas enters the nested inflation chamber through a chamber to chamber vent.

5. The inflatable knee airbag of claim 1, wherein the internal tether limits an inflatable depth of the nested inflatable chamber such that the nested inflatable chamber has a reduced inflatable depth compared to the outer chamber.

6. The inflatable knee airbag of claim 1, wherein the nested inflatable chamber comprises an atmospheric vent that is configured such that inflation gas may exit the nested chamber to outside the inflatable knee airbag.

7. The inflatable knee airbag of claim 1, wherein the internal tether comprises a triangular shape.

8. The inflatable knee airbag of claim 1, wherein the internal tether comprises a trapezoidal shape.

9. The inflatable knee airbag of claim 8, wherein the internal tether comprises an isosceles trapezoidal shape.

2. (canceled)

10. An inflatable knee airbag comprising:

an airbag cushion comprising a plurality of inflatable chambers,

wherein one of the inflatable chambers is nested within an outer inflatable chamber,

wherein the outer inflatable chamber is defined by a first face and a second face that are coupled together along a perimeter,

wherein the nested inflatable chamber is partially defined by an internal tether that is coupled to both of the first and second faces,

wherein the internal tether limits an inflatable depth of the nested inflatable chamber such that the nested inflatable chamber has a reduced inflatable depth compared to the outer inflatable chamber,

wherein the internal tether comprises a chamber to chamber vent that is configured such that inflation gas may travel from the outer inflatable chamber to the nested inflatable chamber, and

wherein the nested inflatable chamber comprises an atmospheric vent that is configured such that inflation gas may exit the nested inflatable chamber to outside the inflatable knee airbag.

12. The inflatable knee airbag of claim 10, wherein the internal tether comprises a first tether portion and a second tether portion that are coupled together.

13. The inflatable knee airbag of claim 12, wherein the first tether portion of the internal tether comprises the chamber to chamber vent.

14. The inflatable knee airbag of claim 13, wherein the first tether portion is located on an upper side of the internal tether such that the chamber to chamber vent is also located on an upper side of the internal tether.

15. The inflatable knee airbag of claim 14, wherein the internal tether further comprises a lower side that is closer to an inflator than the upper side, and wherein the lower side has a smaller width than a maximum width of the internal tether.

16. The inflatable knee airbag of claim 15, wherein the airbag is configured such that during inflation, the lower side of the internal tether causes the inflation gas to be split so that the inflation gas travels around the nested inflatable chamber.

17. The inflatable knee airbag of claim 10, wherein the internal tether comprises a first flange and a second flange, and wherein the first flange is attached to the first face of the inflatable knee airbag and the second flange is attached to the second face.

18. The inflatable knee airbag of claim 10, wherein the atmospheric vent is located on the second face.

19. The inflatable knee airbag of claim 10, wherein the airbag comprises a folded portion that comprises an inflator attachment portion.

20. The inflatable knee airbag of claim 10, wherein the internal tether has a trapezoidal shape.

21. The inflatable knee airbag of claim 20, wherein the internal tether has an isosceles trapezoidal shape.

11. (canceled)

22. A method of making an inflatable knee airbag, wherein the method comprises the steps of:

providing a panel of a flexible material;

removing a first portion of material from a middle portion of the single panel of material;

removing a second portion of material from an opposite side of the middle portion of the single panel of material, such that the single panel of material comprises opposing end portions separated by a middle portion that has a narrower width relative to the end portions;

folding the single panel of material at the reduced width middle portion such that the single panel of material defines a first face and a second face, wherein the first face lies on top of and parallel to the second face;

attaching the first portion of material and the second portion of material together to form an internal tether,

positioning the internal tether between the first face and the second face;

forming a chamber to chamber vent in the internal tether;

forming an inflatable chamber by coupling the internal tether to the first face and the second face; and

forming another inflatable chamber by coupling together the first and second faces along a perimeter of the first and second faces.

23. The method of claim 22, further comprising the steps of forming a first flange and a second flange in the internal tether;

24. The method of claim 23, further comprising the steps of attaching the first flange to the first face and attaching the second flange to the second face, wherein edges of the flange are oriented away from the folded middle portion.

25. The method of claim 22, further comprising the step of forming an atmospheric vent in a predetermined location on the second face such that the atmospheric vent is in fluid communication the inflatable chamber that is formed by coupling the internal tether to the first face and the second face.