Gas generator ignition assembly using a projectile

• US 5,230,531 A
• Filed: 01/06/1992
• Issued: 07/27/1993
• Est. Priority Date: 10/22/1990
• Status: Expired due to Term

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Original Assignee: OEA Incorporated (Autoliv Incorporated)
• Inventors: Butt, Ronald J., Hamilton, Brian K., Parks, Brent A.
• Primary Examiner(s): Kashnikow, Andres
• Assistant Examiner(s): Pomrening, Anthoula
• Application Number:
  US07/817,455
• Time in Patent Office: 568 Days
• Field of Search: 222/5, 280/736, 280/737, 280/741, 280/742, 441/93, 441/94, 137/68.2
• US Class Current: 280/737
• CPC Class Codes: B60R 2021/26035 triggered by mechanical means
• CPC Class Codes: B60R 21/272 with means for increasing the pressure of the gas just before or during liberation, e.g. hybrid inflators
• CPC Class Codes: F42B 3/04 for producing gas under pressure generators of inflation fluid especially adapted for vehicle air bags B60R21/26

Abstract

An ignition assembly in a motor vehicle inflatable safety system is provided, preferably to be used with a projectile. In one embodiment, the ignition assembly includes an actuation piston and an activator, such as a percussion primer(s) and an ignition material, which are separated by a retention pin. When a sufficient force is exerted on the actuation piston, the retention pin fails such that the actuation piston moves and impacts the percussion primer(s) to ignite the propellant within the gas generator. The resulting propellant gases are thereafter provided in a predetermined direction(s). Advantageously, a check valve-like device is employed to substantially reduce the flow of propellant gases in a direction other than the predetermined direction(s). The preferred projectile also includes a body that has a smaller dimension than the projectile piercing head when the projectile is used to separate a closure disk to release stored, pressurized gases in addition to activating the gas generator. In this case, the preferred projectile facilitates the controlled separation of any closure disk used to retain pressurized, stored gases used by the . inflator in addition to the propellant gases.

Claims

1. An ignition assembly for a gas generator in a motor vehicle inflatable safety system, said gas generator having a propellant means for generating propellant gases, upon activation of said ignition assembly, which are provided to said safety system, said ignition assembly comprising:

activator means for igniting said propellant means;

actuation means for engaging said activator means;

first means for propelling said actuation means into engagement with said activator means, wherein said propellant means ignites and propellant gases are provided from said gas generator in a predetermined direction; and

sealing means for substantially reducing the flow of said propellant gases from said gas generator in a direction other than said predetermined direction, wherein said sealing means moves from an inoperative to an operative position after ignition of said propellant means.

2. An assembly, as claimed in claim 1, wherein:

said actuation means comprises a piston having at least one projecting member for engaging said activator means.

3. An assembly, as claimed in claim 1, wherein:

said actuation means comprises a piston having a plurality of projecting members.

4. An assembly, as claimed in claim 3, wherein:

said activator means comprises a plurality of percussion primers, each of said percussion primers being substantially aligned with one of said projecting members.

5. An assembly, as claimed in claim 1, wherein:

said actuation means comprises a piston having a concave portion facing said activator means.

6. An assembly, as claimed in claim 1, wherein:

said activator means comprises at least one percussion primer which is substantially aligned with said actuation means.

7. An assembly, as claimed in claim 1, wherein:

said activator means comprises at least one percussion primer and an ignition material, said ignition material being positioned between said at least one percussion primer and said propellant means.

8. An assembly, as claimed in claim 1, wherein:

said first is a projectile.

9. An assembly, as claimed in claim 1, further comprising:

means for guiding said actuation means toward said activator means.

10. An assembly, as claimed in claim 1, further comprising:

housing means for containing said propellant means and at least a portion of said activator means, said propellant means being positioned between a first end of said housing means and said activator means.

11. An assembly, as claimed in claim 10, further comprising:

actuation support means, interconnected with said housing means, for supporting at least a portion of said actuation means and for guiding said actuation means toward said activator means in a first direction.

12. An assembly, as claimed in claim 11, further comprising:

orifice means on said actuation support means for releasing any gases compressed during movement of said actuation means in said first direction.

13. An assembly, as claimed in claim 11, wherein:

said sealing means comprises a first sealing portion on said actuation support means which is engageable with a second sealing portion on said actuation means.

14. An assembly, as claimed in claim 11, wherein said sealing means comprises:

a first sealing portion on said actuation support means engageable with a second sealing portion on said actuation means;

a concave portion on said actuation means which faces said activator means, whereby gases flowing through said activator means exert a force on said concave portion to move said actuation means and engage said first and second sealing portions.

15. An assembly, as claimed in claim 1, further comprising:

retention means for separating said actuation means from said activator means, wherein said first means exerts a force on said actuation means to overcome said retention means.

16. An assembly, as claimed in claim 15, wherein:

said retention means comprises a retention pin.

17. An assembly, as claimed in claim 1, wherein:

all portions of said actuation means move substantially the same distance for said actuation means to engage said activator means.

18. An inflator for a motor vehicle inflatable safety system, comprising:

housing means for containing a gas generating propellant;

ignition means, interconnected with said housing means, for igniting said propellant, said ignition means comprising an activator means for igniting said propellant, an actuation means for engaging said activator. means, and a retention means for retaining said actuation means in a first position;

actuation support means, interconnected with said housing means, for containing at least a portion of and guiding said actuation means toward said activator means;

projectile means for impacting said actuation means to propel said actuation means from said first position into engagement with said activator means to ignite said propellant; and

means for sealing said actuation means against said actuation support means, said sealing being affected by movement of said actuation means away from said activator means after impacting said activator means.

19. An inflator, as claimed in claim 18, wherein:

said actuation means comprises a piston having at least one projecting member for contacting at least a portion of said activator means.

20. An inflator, as claimed in claim 18, wherein:

said actuation means comprises a piston having a plurality of projecting members for contacting at least a portion of said activator means in a plurality of locations.

21. An inflator, as claimed in claim 20, wherein:

said activator means comprises a plurality of percussion primers, each said percussion primer being substantially aligned with one of said projecting members.

22. An inflator, as claimed in claim 18, wherein:

a portion of said actuation means which faces said activator means has a greater cross-sectional area than a portion of said actuation means which is engageable by said projectile means.

23. An inflator, as claimed in claim 18, wherein:

said activator means comprises at least one percussion primer and an ignitable material.

24. An inflator, as claimed in claim 18, wherein:

said retention means is a retention pin which engages said actuation means.

25. An inflator, as claimed in claim 18, wherein:

said retention means is a retention pin which engages said actuation means and said actuation support means.

26. An inflator, as claimed in claim 18, wherein:

said actuation support means comprises a first sealing portion engageable with a second sealing portion of said actuation means, the engagement of said first and second sealing portions substantially restricting the flow of gases from said housing means through said actuation support means and said actuation means.

27. An inflator, as claimed in claim 26, wherein:

said actuation means comprises a concave portion which faces said activator means, whereby gases flowing through said activator means exert a force on said concave portion to move said actuation means to engage said first and second sealing portions.

28. An inflator, as claimed in claim 18, wherein:

said actuation support means further comprises orifice means for reducing the resistance to the movement of said actuation means toward said activator means.

29. An assembly, as claimed in claim 18, wherein:

all portions of said actuation means move substantially the same distance for said actuation means to engage said activator means.

30. A method for activating an inflator in a motor vehicle inflatable safety system, comprising the steps of:

retaining a stored gas in a housing;

releasing said stored gas;

providing an actuation support, said actuation support being interconnected with a gas generator positioned within said housing, said gas generator containing a propellant means for providing propellant gases and having an activator means for igniting said propellant means;

positioning an actuation piston means for engaging said activator means at least partially within said actuation support;

moving said actuation piston means in a first direction toward said activator means;

engaging said actuation piston means and said activator means to ignite said propellant means; and

moving said actuation piston means in a second direction opposite said first direction to seal at least a portion of said actuation piston means against at least a portion of said actuation support, wherein the flow of gases through said actuation support and said actuation piston means is substantially limited.

31. A method, as claimed in claim 30, further comprising the steps of:

retaining said actuation piston means relative to said actuation support in a first position with a retaining device; and

impacting said actuation piston means to overcome said retaining device before said moving said actuation piston means in a first direction step.

32. A method, as claimed in claim 30, further comprising the step of:

releasing any gases compressed during said moving said actuation piston means in a first direction step.

33. A method for providing propellant gases to a motor vehicle inflatable safety system, comprising the steps of:

igniting a propellant means for generating propellant gases, said propellant means being positioned in a gas generator having at least one gas generator outlet, wherein said igniting step creates a flow path from said gas generator for said propellant gases in addition to said at least one gas generator outlet;

providing said propellant gases to said system from said gas generator through said at least one gas generator outlet;

sealing said flow path after said igniting step and during at least a portion of said providing step.

34. An apparatus for providing a supply of gas, comprising:

first housing means for containing a pressurized gas;

gas generator means for providing a propellant gas;

projectile means for opening a sealing portion of said first housing means to release said pressurized gas and for impacting an activating portion of said gas generator means to generate said propellant gas, wherein said projectile means has head and body portions with said head portion leading said body portion and said entire head portion penetrating and passing through said sealing portion, adjacent parts of said head and body portions having different sizes, said adjacent part of said head portion having a greater size than said adjacent part of said body portion.

35. An apparatus, as claimed in claim 34, further comprising:

36. An apparatus, as claimed in claim 34, wherein:

said head portion is engageable with said activating portion of said gas generator means.

37. An apparatus, as claimed in claim 34, wherein:

said adjacent part of said head portion has a greater circumference than said adjacent part of said body portion.

38. An apparatus, as claimed in claim 34, wherein:

said projectile means has a central axis and said head portion further comprises a first head portion which generally tapers away from said central axis toward said adjacent part of said head portion.

39. An apparatus, as claimed in claim 34, further comprising:

sleeve means for guiding said projectile means toward said activating portion of said gas generator means.

40. An apparatus, as claimed in claim 39, wherein:

said head portion and at least a portion of said adjacent part of said body portion extend beyond an end of said sleeve means when said head portion engages said activating portion of said gas generator means, said adjacent part of said body portion interconnecting said head portion and a first body part of said body portion which is at least partially retained within said sleeve means.

41. An apparatus, as claimed in claim 34, wherein:

said opened sealing portion comprises a plurality of segments which remain attached to said first housing means after said at least a portion of said projectile means penetrates and passes therethrough, said segments moving in a direction substantially opposite of a direction of movement of said projectile means, whereby said segments are free from substantial engagement with said body portion during said movement of said segments.

42. An inflator for a motor vehicle inflatable safety system, comprising:

housing means for containing a gas generating propellant;

ignition means, interconnected with said housing means, for igniting said propellant, said ignition means comprising an activator means for igniting said propellant, an actuation means for engaging said activator means, and a retention means for retaining said actuation means in a first position, said actuation means comprising a piston having a plurality of projecting members for contacting at least a portion of said activator means in a plurality of locations; and

projectile means for impacting said actuation means to propel said actuation means from said first position into engagement with said activator means to ignite said propellant.

43. An inflator, as claimed in claim 42, wherein:

said activator means comprises a plurality of percussion primers, each said percussion primer being substantially aligned with one of said projecting members.

44. An inflator for a motor vehicle inflatable safety system, comprising:

housing means for containing a gas generating propellant;

ignition means, interconnected with said housing means, for igniting said propellant, said ignition means comprising an activator means for igniting said propellant, an actuation means for engaging said activator means, and a retention means for retaining said actuation means in a first position; and

projectile means for impacting said actuation means to propel said actuation means form said first position into engagement with said activator means to ignite said propellant, wherein a portion of said actuation means which faces said activator means has a greater cross-sectional area than a portion of said actuation means which is engageable by said projectile means.

45. An inflator for a motor vehicle inflatable safety system, comprising:

housing means for containing a gas generating propellant;

ignition means, interconnected with said housing means, for igniting said propellant, said ignition means comprising an activator means for igniting said propellant, an actuation means for engaging said activator means, a retention means for retaining said actuation means in a first position, and an actuation support means, interconnected with said housing means, for engaging at least a portion of said actuation means, said actuation support means comprising a first sealing portion engageable with a second sealing portion of said actuation means; and

projectile means for impacting said actuation means to propel said actuation means from said first position into engagement with said activator means to ignite said propellant, wherein said actuation means comprises a concave portion which faces said activator means whereby gases flowing through said activator means exert a force on said concave portion to move said actuation means to engage said first and second sealing portions and wherein the engagement of said first and second sealing portions substantially restricts the flow of gases from said housing means through said actuation support means and said actuation means.

46. An inflator for a motor vehicle inflatable safety system, comprising:

housing means for containing a gas generating propellant;

ignition means, interconnected with said housing means, for igniting said propellant, said ignition means comprising an activator means for igniting said propellant, an actuation means for engaging said activator means, a retention means for retaining said actuation means in a first position, and an actuation support means, interconnected with said housing means, for engaging at least a portion of said actuation means; and

projectile means for impacting said actuation means to propel said actuation means from said first position into engagement with said activator means to ignite said propellant, wherein said actuation support means further comprises orifice means for reducing resistance to the movement of said actuation means toward said activator means.