Dual stage air bag inflator

• US 8,444,179 B2
• Filed: 12/06/2006
• Issued: 05/21/2013
• Est. Priority Date: 12/06/2006
• 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: McFarland, Eric R.
• Primary Examiner(s): Dickson, Paul N
• Assistant Examiner(s): Freedman, Laura
• Application Number:
  US11/634,504
• Publication Number:
  US 20080136152A1
• Time in Patent Office: 2,358 Days
• Field of Search: 102/530, 280/736, 280/737, 280740-742
• US Class Current: 280/736
• CPC Class Codes: B60R 2021/26029 Ignitors
• CPC Class Codes: B60R 2021/26082 Material
• CPC Class Codes: B60R 2021/2642 comprising a plurality of combustion chambers or sub-chambers
• CPC Class Codes: B60R 2021/2648 comprising a plurality of combustion chambers or sub-chambers
• CPC Class Codes: B60R 21/26 characterised by the inflation fluid source or means to control inflation fluid flow arrangement or mounting thereof to the vehicle B60R21/20; blasting cartridges for producing gas under pressure in general F42B3/04; initiators or igniters therefor F42B3/10
• CPC Class Codes: B60R 21/263 using a variable source, e.g. plural stage or controlled output hybrid inflators B60R21/272
• CPC Class Codes: B60R 21/264 using instantaneous generation of gas, e.g. pyrotechnic B60R21/268 takes precedence
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder

Abstract

An apparatus (12) includes a primary housing (20) constructed from sheet metal by stamping, a primary inflation fluid source (100), a secondary housing (70) constructed from sheet metal by stamping, and a secondary inflation fluid source (200). The primary inflation fluid source (100) is located in the primary housing (20) and is actuatable to effect a primary flow of inflation fluid out of the primary housing to inflate the inflatable device (14). The secondary housing (70) is disposed within the primary housing (20). The secondary inflation fluid source (200) is located in the secondary housing (70) and is actuatable to affect a secondary flow of inflation fluid to supplement the primary flow of inflation fluid. The secondary housing (70) has a first portion (77) that moves at least partially out of engagement with a second portion (74) of the secondary housing (70) when the secondary inflation fluid source is actuated.

Claims

1. An apparatus for providing inflation fluid for inflating an inflatable vehicle occupant protection device, said apparatus comprising:

a primary housing constructed from sheet metal by stamping;

a primary inflation fluid source in said primary housing actuatable to effect a primary flow of inflation fluid out of said primary housing to inflate the inflatable device, said primary inflation fluid source prior to actuation being in fluid communication with the inflatable device;

a secondary housing constructed from sheet metal by stamping, said secondary housing being disposed within said primary housing; and

a secondary inflation fluid source in said secondary housing actuatable to affect a secondary flow of inflation fluid to supplement the primary flow of inflation fluid,

said secondary housing having a first portion that moves at least partially out of engagement with a second portion of said secondary housing when said secondary inflation fluid source is actuated.

2. The apparatus as set forth in claim 1 wherein said first portion of said secondary housing comprises a dome shaped cap having an interference fit with said secondary housing.

3. The apparatus as set forth in claim 1 wherein said primary inflation fluid source comprises a primary igniter assembly and a primary propellant.

4. The apparatus as set forth in claim 3 wherein said secondary inflation fluid source comprises a secondary igniter assembly and a secondary propellant.

5. The apparatus as set forth in claim 1 wherein said primary housing comprises a cup-shaped diffuser and a closure secured to said diffuser, said diffuser and said closure defining a primary combustion chamber for said primary inflation fluid source.

6. The apparatus as set forth in claim 5 wherein said first portion of said secondary housing comprises a cup member and said second portion of said secondary housing comprises a cap member secured to said cup member, said cup member and said cap member defining a secondary combustion chamber.

7. The apparatus as set forth in claim 1 wherein said primary housing is centered on a first axis and said secondary housing is centered on a second axis radially offset from and parallel to said first axis.

8. The apparatus as set forth in claim 7 further comprising a primary igniter assembly for igniting said primary inflation fluid source, said primary igniter assembly being centered on a third axis radially offset from and parallel to said first axis and radially offset from and parallel to said second axis.

9. The apparatus as set forth in claim 1 wherein said first portion of said secondary housing comprises an upper end portion and said second portion of said secondary housing comprises an opposite lower end portion, said upper end portion comprising a cap secured to said lower end portion and abutting an inner surface of said primary housing.

10. The apparatus as set forth in claim 1 further comprising an elastomeric seal for sealing said secondary housing to an inner surface of said primary housing.

11. An inflator for providing inflation fluid for inflating an inflatable vehicle occupant protection device, said inflator comprising:

a primary housing having an upper wall and a lower wall opposite said upper wall, said primary housing being constructed from sheet metal by stamping;

a primary inflation fluid source disposed within said primary housing actuatable to deform said primary housing to move said upper wall and said lower wall away from each other;

a secondary housing constructed from sheet metal by stamping, said secondary housing being disposed within said primary housing, said secondary housing having an upper portion abutting said upper wall of said primary housing and a lower portion abutting said lower wall of said primary housing prior to actuation of said primary inflation fluid source; and

a secondary inflation fluid source disposed within said secondary housing actuatable to move said upper portion of said secondary housing at least partially out of engagement with said lower portion of said secondary housing subsequent to said primary housing being deformed by said primary inflation fluid source.

12. The inflator as set forth in claim 11 wherein said upper portion of said secondary housing comprises a cap having an interference fit with said lower portion of said secondary housing.

13. The inflator as set forth in claim 11 wherein said primary housing has a primary circular opening for securing a primary igniter to said primary housing.

14. The inflator as set forth in claim 13 wherein said primary housing has a secondary circular opening for securing a secondary igniter to said primary housing.

15. The inflator as set forth in claim 14 wherein said secondary housing has a circular opening concentric with said secondary circular opening of said primary housing.

16. The inflator as set forth in claim 11 wherein said primary housing has a curved inner surface for securing said secondary housing within said primary housing.

17. The inflator as set forth in claim 11 wherein said secondary housing is secured to said primary housing by an elastomeric seal.

18. The inflator as set forth in claim 11 wherein said primary housing comprises an upper portion and a lower portion welded to said upper portion.

19. The inflator as set forth in claim 11 wherein said primary housing includes a recessed mounting portion for securing a primary igniter to said primary housing.

20. The inflator as set forth in claim 19 wherein said secondary housing includes a recessed mounting portion for securing a secondary igniter to said secondary housing.

21. The inflator as set forth in claim 11 wherein said primary housing includes an annular mounting flange for securing said inflator to a vehicle.