Dual stage inflator

• US 5,398,966 A
• Filed: 06/22/1994
• Issued: 03/21/1995
• Est. Priority Date: 03/03/1993
• Status: Expired due to Fees

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Original Assignee: Morton International Incorporated (Autoliv Incorporated)
• Inventors: Hock, Christopher
• Primary Examiner(s): Focarino, Margaret A.
• Assistant Examiner(s): English, Peter C.
• Application Number:
  US08/264,118
• Time in Patent Office: 272 Days
• Field of Search: 280/741, 280/736, 280/742, 280/735, 280/734, 280/728 R, 102/530, 102/531, 102/202, 102/288, 102/373, 422/164, 422/165, 422/166
• US Class Current: 280/736
• CPC Class Codes: B60R 2021/26029 Ignitors
• CPC Class Codes: B60R 2021/26041 of elongated shape
• CPC Class Codes: B60R 2021/2633 with a plurality of inflation levels
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder

Abstract

A device is provided for increasing the surface area of the gas generant used in an automotive safety air bag module. Depending on crash conditions, the surface area of the gas generant is increased by shattering the gas generant wafers. One embodiment utilizes a squib having a high brisance zone which upon activation shatters the gas generant wafers. Alternatively, a dual function squib is used which can produce mechanical forces which force a breaking object to impact on the gas generating wafers thereby shattering them and increasing the surface area of the gas generant.

Claims

1. A gas generator for inflating a vehicle inflatable restraint cushion, the generator comprising:

an elongated housing including a tubular combustion chamber having first and second end portions;

means for closing said end portions;

a gas generating material formed into a plurality of gas generating wafers, arranged along the length of said tubular combustion chamber and spaced from each other in a side-by-side array;

at least one igniter means in spaced relationship from said gas generating wafers, for igniting said gas generating wafers;

a radially extending plate located in spaced relation to one end of said gas generating wafers;

at least one squib, located adjacent said radially extending plate, in spaced relationship to said at least one igniter means and which upon activation ignites said at least one igniter means; and

aperture means in said tubular combustion chamber for directing generated gas from said tubular combustion chamber to the vehicle inflatable restraint cushion;

wherein said at least one squib has a high output which upon activation causes said radially extending plate to impact on said gas generating wafers thereby causing said gas generating wafers to shatter, thereby increasing the surface area of said gas generating material.

2. The gas generator of claim 1 wherein said at least one squib is a dual output squib having a standard output and a high output.

3. The gas generator of claim 2 wherein said dual output squib is attached to the first end portion of said combustion chamber and a standard squib is attached to the second end portion of said combustion chamber.

4. The gas generator of claim 2 wherein a first dual output squib is attached to the first end portion of said combustion chamber and a second dual output squib is attached to the second end portion of said combustion chamber.

5. The gas generator of claim 4 wherein said combustion chamber further comprises filter means for filtering the gas.

6. The gas generator of claim 1 wherein said at least one squib is attached to the first end portion of said combustion chamber.

7. The gas generator of claim 1 wherein said combustion chamber further comprises cooling means for cooling the gas.

8. The gas generator of claim 1 wherein said gas generating wafers include fracture zones on the surface thereof whereat said gas generating wafers preferably shatter.

9. A gas generator for inflating a vehicle inflatable restraint cushion, the generator comprising:

an elongated housing including a tubular combustion chamber having first and second end portions;

means for closing said end portions, said tubular combustion chamber comprising;

a gas generating material formed into a plurality of gas generating wafers, arranged along the length of said tubular combustion chamber and spaced from each other in a side-by-side array, said gas generating wafers each having a central region having a through apertures, said apertures defining inner wall surfaces;

an igniter tube having a first end and a second end and containing at least one igniter material, said tube passing through said apertures in said gas generating wafers;

at least one fracture means located in spaced relation to at least said first end of said igniter tube;

at least one squib, located adjacent said at least one fracture means, in spaced relationship to said igniter tube and which upon activation initiates said igniter material; and

aperture means in said tubular combustion chamber for directing generated gas from said tubular combustion chamber to the vehicle inflatable restraint cushion,

wherein said at least one squib has a high output which upon activation impacts on said at least one fracture means forcing said at least one fracture means into at least said first end of said tube forcing said tube to radially expand and engage said gas generating wafer aperture inner wall surfaces causing said gas generating wafers to shatter thereby increasing the surface area of said gas generating material.

10. The gas generator of claim 9 wherein said igniter tube has fracture lines running the length thereof.

11. The gas generator of claim 9 wherein said at least one squib is a dual output squib having a standard output and a high output.

12. The gas generator of claim 9 wherein said at least one squib is attached to said first end portion of said combustion chamber.

13. A gas generator for inflating a vehicle inflatable restraint cushion, said gas generator comprising:

a housing including a tubular combustion chamber having first and second end portions;

means for closing said end portions;

a gas generating material formed into a plurality of gas generating wafers, arranged along the length of said tubular combustion chamber and spaced from each other in a side-by-side array;

wafer shatter means in spaced relationship with at least a first of said gas generating wafers;

at least one igniter means for igniting said gas generating wafers, said at least one igniter means being in spaced relationship with said gas generating wafers;

at least one squib, located adjacent said wafer shatter means, in spaced relationship to said at least one igniter means, said at least one squib upon activation having a high output and igniting said at least one igniter means; and

aperture means in said tubular combustion chamber for directing generated gas from said tubular combustion chamber to the vehicle inflatable restraint cushion;

wherein said wafer shatter means upon receipt of the high output of said at least one squib effects shattering of at least said first of said gas generating wafers thereby increasing the surface area of said gas generating material.

14. The gas generator of claim 13 wherein said at least one squib is a dual output squib having a standard output and a high output.

15. The gas generator of claim 13 wherein said at least one squib is attached to the first end portion of said combustion chamber.

16. The gas generator of claim 13 wherein said combustion chamber further comprises cooling means for cooling the gas.

17. The gas generator of claim 13 wherein said combustion chamber further comprises filter means for filtering the gas.

18. The gas generator of claim 13 wherein said wafer shatter means comprises a radially extending plate located in spaced relation to one end of said gas generating wafers and wherein upon activation of said at least one squib said output causes said plate to impact on said gas generating wafers.

19. The gas generator of claim 13 wherein:

said wafer shatter means comprises said gas generating wafers each having a central region having a through aperture, said apertures defining inner wall surfaces;

said at least one igniter means comprises an igniter tube having a first and a second end and containing igniter material, said tube passing through said apertures in said gas generating wafers;

wherein said wafer shatter means further comprises at least one fracture means located in spaced relation to at least said first end of said igniter tube; and

wherein upon activation of said at least one squib said output forces said at least one fracture means into at least said first end of said tube forcing said tube to radially expand and engage said gas generating wafer aperture inner wall surfaces.