Gas generation and ignition system for airbag inflation

• US 5,620,205 A
• Filed: 02/23/1995
• Issued: 04/15/1997
• Est. Priority Date: 03/14/1994
• Status: Expired due to Fees

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Original Assignee: Morton International Incorporated (Autoliv Incorporated)
• Inventors: Mitson, Scott C., Taylor, Robert D., Green, David J., Lauritzen, Donald R.
• Primary Examiner(s): Ellis, Christopher P.
• Application Number:
  US08/392,570
• Time in Patent Office: 782 Days
• Field of Search: 280/741, 280/736, 422/166, 422/164, 422/165, 102/288
• US Class Current: 280/741
• CPC Class Codes: B60R 2021/26041 of elongated shape
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder
• CPC Class Codes: C06B 45/00 Compositions or products which are defined by structure or arrangement of component of product explosive charges of particular form or shape F42B1/00, F42B3/00
• CPC Class Codes: C06C 9/00 Chemical contact igniters; Chemical lighters
• CPC Class Codes: F42B 3/04 for producing gas under pressure generators of inflation fluid especially adapted for vehicle air bags B60R21/26
• CPC Class Codes: F42B 5/16 characterised by composition or physical dimensions or form of propellant charge, with or without projectile, or powder chemical composition C06B; F42B5/24 takes precedence
• CPC Class Codes: F42C 19/0803 characterised by the combination of per se known chemical composition in the priming substance
• CPC Class Codes: F42C 19/0823 Primers or igniters for the initiation or the propellant charge in a cartridged ammunition primers for caseless ammunition F42C19/085
• CPC Class Codes: F42C 19/0834 Arrangements of a multiplicity of primers or detonators dispersed within a propellant charge for increased efficiency

Abstract

An inflation system for automotive airbags which comprises a pyrogenic solid grain with igniter strips provided in grooves on its external surface. Upon ignition, the solid grain burns from its external surface inwardly while allowing the generated gas to pass freely from its external surface. Preferably both the pyrogenic solid grain and the igniter strips are extrusions, providing a simplified, less expensive manufacture.

Claims

1. In an airbag inflator which comprises a gas generating solid grain and an igniter strip to ignite said gas generating solid grain, the improvement comprising said gas generating solid grain having at least one groove on its external surface, said groove being shaped to receive an igniter strip having a shape complementary to at least a portion of the shape of said groove;

and wherein said gas generating solid grain does not contain any cavities capable of containing an igniter strip other than said at least one groove on its external surface.

2. The airbag inflator as defined in claim 1, wherein said gas generating solid grain is a molded solid grain.

3. In an airbag inflator which comprises a gas generating solid grain and an igniter strip to ignite said gas generating solid grain, the improvement comprising said gas generating solid grain having at least one groove on its external surface, said groove being shaped to receive an igniter strip having a shape complementary to at least a portion of the shape of said groove, and wherein said gas generating solid grain is elongated and has a substantially constant cross-section along its elongated axis.

4. The airbag inflator as defined in claim 3, wherein said elongated gas generating solid grain comprises a single integral solid body.

5. The airbag inflator as defined in claim 3, wherein said elongated gas generating solid grain comprises at least two integral solid bodies.

6. The airbag inflator as defined in claim 5, wherein the elongated axis of all of said integral solid bodies lie on the same line.

7. In an airbag inflator which comprises a gas generating solid grain and an igniter strip to ignite said gas generating solid grain, the improvement wherein said gas generating solid grain is elongated having a substantially constant cross-section along its elongated axis and has at least one groove on its external surface, said groove being shaped to receive said igniter strip having a shape complementary to at least a portion of the shape of said groove, said elongated gas generating solid grain comprising at least two integral solid bodies and further comprising at least one auxiliary solid body having substantially the same cross-section as said at least two solid bodies of elongated gas generating solid grain, and wherein said auxiliary elongated body is made of a material having substantially different gas generating properties than is provided by the material of said gas generating solid grain.

8. The airbag inflator as defined in claim 7, wherein said auxiliary solid body is made of a material which produces substantially no gas upon activation of the inflator.

9. The airbag inflator as defined in claim 7, wherein said auxiliary solid body is provided such that its elongated solid axis lies on substantially the same line as does the elongated axis of said integral solid bodies of gas generating solid grain.

10. In an airbag inflator which comprises a gas generating solid grain and an igniter strip to ignite said gas generating solid grain, the improvement comprising said gas generating solid grain having at least one groove on its external surface, said groove being shaped to receive said igniter strip having a shape complementary to at least a portion of the shape of said groove and said groove having a shape which holds said igniter strip within said groove.

12. The airbag inflator as defined in claim 10, wherein said groove comprises a primary slot extending from the external surface of said gas generating solid grain into the interior of said grain.

11. In an airbag inflator which comprises a gas generating solid grain and an igniter strip to ignite said gas generating solid grain, the improvement comprising said gas generating solid grain having at least one groove on its external surface, said groove being shaped to receive an igniter strip having a shape complementary to at least a portion of the shape of said groove, and at least one of said igniter strips being retained in said groove by a portion thereof which is wider than a part of said groove which is located closer to the grain surface than is said portion of said igniter strip.

13. The airbag inflator of claim 11, wherein said groove further comprises auxiliary slots extending from said primary slot within the interior of said grain.

14. The airbag inflator of claim 13, wherein said groove is in a generally cruciform shape.

15. The airbag inflator of claim 14, wherein said igniter strip is formed as a solid body of an ignition material.

16. The airbag inflator of claim 15, wherein said igniter strip is formed as an extrusion of said ignition material.

17. The airbag inflator of claim 15, wherein said igniter strip is formed by molding said ignition material.

18. The airbag inflator of claim 15, wherein said strip igniter extends the full length of said at least one groove.

19. In an airbag inflator which comprises a gas generating solid grain and an igniter strip to ignite said gas generating solid grain, the improvement comprising said gas generating solid grain having at least one groove on its external surface, said groove being shaped to receive said igniter strip having a shape complementary to at least a portion of the shape of said groove, and at least one of said igniter strips located within at least one of said grooves, with at least one end of said igniter strip extending past at least one end of said at least one groove.

20. The airbag inflator of claim 19, which further comprises an initiation means capable of initiating ignition in response to activation by a signal transmitted from a sensor and wherein said extension of said strip igniter extends into a space wherein it would be contacted by ignition products produced by activation of said initiation means.

21. The airbag inflator of claim 19, which further comprises an auto-ignition means which is capable of initiating ignition when activated by the inflator reaching a temperature in the range of 300°

to 450°

F., and wherein said extension of said igniter strip extends into a space wherein it would be contacted by the ignition products produced by activation of said auto-ignition means.

22. In an airbag inflator which comprises a gas generating solid and at least one igniter strip to ignite said gas generating solid, wherein said gas generating solid comprises at least two integral solid bodies, each having at least one groove on its external surface, and at least one of said igniter strip in said at least one groove in at least one of said integral solid bodies.

23. An airbag inflator as defined in claim 22, further comprising an auxiliary solid body formed of a material which provides gas generating characteristics substantially different from those of said gas generating solid.

24. An airbag inflator as defined in claim 23, wherein the material of said auxiliary solid body produces essentially no gas during activation of the airbag.