Air bag inflator including plural burst disks

• US 6,206,414 B1
• Filed: 08/05/1998
• Issued: 03/27/2001
• Est. Priority Date: 08/05/1998
• Status: Expired due to Fees

• Current Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen), TRW Vehicle Safety Systems Incorporated (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Cook, Fred J., Gudewich, Kenneth K., Nelson, Tracy L., Johnson, Darrin L., Greenlee, Chad L.
• Primary Examiner(s): Johnson, Brian L.
• Assistant Examiner(s): WINNER, TONY H
• Application Number:
  US09/129,710
• Time in Patent Office: 965 Days
• Field of Search: 280/734, 280/736, 280/737
• US Class Current: 280/734
• CPC Class Codes: B60R 2021/26094 characterised by fluid flow controlling valves
• CPC Class Codes: B60R 2021/2633 with a plurality of inflation levels
• CPC Class Codes: B60R 21/264 using instantaneous generation of gas, e.g. pyrotechnic B60R21/268 takes precedence
• 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: F16K 13/06 constructed to be ruptured by an explosion

Abstract

An air bag inflator (10) includes a container (12) defining a chamber (14), and inflation fluid (66) under pressure in the chamber. A first opening (41) in the container (12) enables fluid flow from the chamber (14) to an inflatable device (32). A first burst disk (60) extends across the first opening (41) and is rupturable in response to an increase in the pressure differential across the first burst disk to a level above a first predetermined pressure differential. The inflator (10) includes a first igniter (90) for, when actuated, increasing the pressure differential across the first burst disk (60) to a level above the first predetermined pressure differential to rupture the first burst disk. A second opening (43) in the container (12) enables fluid flow from the chamber (14) to the inflatable device (32). A second burst disk (62) extends across the second opening (43) and is rupturable in response to an increase in the pressure differential across the second burst disk to a second predetermined pressure differential greater than the first differential. The inflator (10) includes a second igniter (110) actuatable independently of the first igniter (90) for, when actuated, increasing the pressure differential across the second burst disk (62) to a level above the second predetermined pressure differential to rupture the second burst disk.

Claims

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

a container defining a gas storage chamber;

inflation fluid under pressure in said gas storage chamber;

a first opening in said container for enabling fluid flow from said gas storage chamber to the inflatable device;

a first burst disk extending across said first opening and being rupturable in response to an increase in the pressure differential across said first burst disk to a level above a first predetermined pressure differential;

first pressurizing means for, when actuated, increasing the pressure differential across said first burst disk to a level above the first predetermined pressure differential to rupture said first burst disk;

a second opening in said container for directing fluid flow from said gas storage chamber to the inflatable device;

a second burst disk extending across said second opening and being rupturable in response to an increase in the pressure differential across said second burst disk to a second predetermined pressure differential greater than the first differential; and

second pressurizing means actuatable independently of said first pressurizing means for, when actuated, increasing the pressure differential across said second burst disk to a level above the second predetermined pressure differential to rupture said second burst disk,

said apparatus having an actuated condition in which said first burst disk is ruptured and said second burst disk is unruptured so that all of said inflation fluid flows through only said first opening.

2. An apparatus as set forth in claim 1 having a first actuated condition in which said first burst disk is ruptured and said second burst disk is unruptured so that all of said inflation fluid flowing from said gas storage chamber flows along a fluid flow path which extends through only said first opening;

said apparatus having a second actuated condition in which the pressure in said gas storage chamber increases to a level at which both said first burst disk and said second burst disk are ruptured so that a first portion of said inflation fluid flows from said gas storage chamber along a fluid flow path which extends through only said first opening and a second portion of said inflation fluid flows from said gas storage chamber along a fluid flow path which extends through only said second opening.

3. An apparatus as set forth in claim 2 comprising a diffuser defining a diffuser chamber, each one of said first and second openings at least partially defining a separate fluid flow path extending between said gas storage chamber and said diffuser chamber.

4. An apparatus as set forth in claim 1 wherein said first burst disk is thinner than said second burst disk.

5. An apparatus as set forth in claim 1 wherein said first burst disk has one or more score lines and said second burst disk is free of score lines.

6. An apparatus as set forth in claim 1 wherein said first burst disk has score lines and said second burst disk has score lines which are shallower than said score lines of said first burst disk.

7. An apparatus as set forth in claim 1 wherein said container comprises a wall portion including said first and second openings, said first opening at least partially defining a first fluid flow path extending between said gas storage chamber and the inflatable device, said second opening at least partially defining a second fluid flow path spaced apart from said first opening and extending between said chamber and the inflatable device.

8. An apparatus as set forth in claim 1 having a first actuated condition in which said first burst disk is ruptured and said second burst disk is unruptured so that all of said inflation fluid flows from the gas storage chamber in a fluid flow path which extends through only said first opening;

and

said apparatus having a second actuated condition in which the pressure in said gas storage chamber increases to a level at which both said first burst disk and said second burst disk are ruptured so that a first portion of said inflation fluid flows from said gas storage chamber along a fluid flow path which extends through only said first opening and a second portion of said inflation fluid flows from said gas storage chamber along a fluid flow path which extends through both said first opening and said second opening.

9. An apparatus as set forth in claim 8 wherein said first burst disk when unruptured blocks contact of said inflation fluid in said gas storage chamber with said second burst disk.

10. An apparatus as set forth in claim 8 wherein said second burst disk is exposed to the fluid pressure in said gas storage chamber when said first burst disk is unruptured.

11. An apparatus as set forth in claim 8 wherein said first burst disk is thinner than said second burst disk.

12. An apparatus as set forth in claim 8 wherein said first burst disk has one or more score lines and said second burst disk is free of score lines.

13. An apparatus as set forth in claim 8 wherein said first burst disk has score lines and said second burst disk has score lines which are shallower than said score lines of said first burst disk.

14. An apparatus for inflating an inflatable vehicle occupant protection device, said apparatus comprising:

a container defining a gas storage chamber;

inflation fluid under pressure in said gas storage chamber;

a first opening in said container for enabling fluid flow from said gas storage chamber to the inflatable device;

a first burst disk area extending across said first opening and being rupturable in response to an increase in the pressure differential across said first burst disk area to a level above a first predetermined pressure differential;

first pressurizing means for, when actuated, increasing the pressure differential across said first burst disk area to a level above the first predetermined pressure differential to rupture said first burst disk area;

a second opening in said container for directing fluid flow from said gas storage chamber to the inflatable device;

a second burst disk area extending across said second opening and being rupturable in response to an increase in the pressure differential across said second burst disk area to a second predetermined pressure differential greater than the first differential; and

second pressurizing means actuatable independently of said first pressurizing means for, when actuated, increasing the pressure differential across said second burst disk area to a level above the second predetermined pressure differential to rupture said second burst disk area,

said apparatus having an actuated condition in which only said first burst disk area ruptures and said second burst disk area does not rupture.

15. An apparatus as set forth in claim 14 having a first actuated condition in which said first burst disk area is ruptured and said second burst disk area is unruptured so that all of said inflation fluid flowing from said gas storage chamber flows along a fluid flow path which extends through only said first opening;

said apparatus having a second actuated condition in which the pressure in said gas storage chamber increases to a level at which both said first burst disk area and said second burst disk area are ruptured so that a first portion of said inflation fluid flows from said gas storage chamber along a fluid flow path which extends through only said first opening and a second portion of said inflation fluid flows from said gas storage chamber along a fluid flow path which extends through only said second opening.

16. An apparatus for inflating an inflatable vehicle occupant protection device, said apparatus comprising:

a container defining a gas storage chamber;

inflation fluid under pressure in said gas storage chamber;

a first opening in said container for enabling fluid flow from said gas storage chamber to the inflatable device;

a first burst disk extending across said first opening and being rupturable in response to an increase in the pressure differential across said first burst disk to a level above a first predetermined pressure differential;

first pressurizing means for, when actuated, increasing the pressure differential across said first burst disk to a level above the first predetermined pressure differential to rupture said first burst disk;

a second opening in said container for directing fluid flow from said gas storage chamber to the inflatable device;

a second burst disk extending across said second opening and being rupturable in response to an increase in the pressure differential across said second burst disk to a second predetermined pressure differential greater than the first differential; and

second pressurizing means actuatable independently of said first pressurizing means for, when actuated, increasing the pressure differential across said second burst disk to a level above the second predetermined pressure differential to rupture said second burst disk,

said second pressurizing means including a larger amount of ignitable material than said first pressurizing means and said second pressurizing means producing a larger amount of combustion products than said first pressurizing means.

17. An apparatus as set forth in claim 16 wherein said first pressurizing means is incapable of increasing the pressure differential across said second burst disk to a level equal to or above the second predetermined differential.

18. An apparatus for inflating an inflatable vehicle occupant protection device, said apparatus comprising:

a container defining a gas storage chamber;

inflation fluid under pressure in said gas storage chamber;

a first opening in said container for enabling fluid flow from said gas storage chamber to the inflatable device;

a first burst disk extending across said first opening and being rupturable in response to an increase in the pressure differential across said first burst disk to a level above a first predetermined pressure differential;

first pressurizing means for, when actuated, increasing the pressure differential across said first burst disk to a level above the first predetermined pressure differential to rupture said first burst disk;

a second opening in said container for directing fluid flow from said gas storage chamber to the inflatable device;

a second burst disk extending across said second opening and being rupturable in response to an increase in the pressure differential across said second burst disk to a second predetermined pressure differential greater than the first differential; and

second pressurizing means actuatable independently of said first pressurizing means for, when actuated, increasing the pressure differential across said second burst disk to a level above the second predetermined pressure differential to rupture said second burst disk,

said first burst disk, when unruptured, blocking flow of said inflation fluid through both said first opening and said second opening.

19. An apparatus for inflating an inflatable vehicle occupant protection device, said apparatus comprising:

a container defining a gas storage chamber;

inflation fluid under pressure in said gas storage chamber;

a first opening in said container for enabling fluid flow from said gas storage chamber to the inflatable device;

a first burst disk extending across said first opening and being rupturable in response to an increase in the pressure differential across said first burst disk to a level above a first predetermined pressure differential;

first pressurizing means for, when actuated, increasing the pressure differential across said first burst disk to a level above the first predetermined pressure differential to rupture said first burst disk;

a second opening in said container for directing fluid flow from said gas storage chamber to the inflatable device;

a second burst disk extending across said second opening and being rupturable in response to an increase in the pressure differential across said second burst disk to a second predetermined pressure differential greater than the first differential; and

second pressurizing means actuatable independently of said first pressurizing means for, when actuated, increasing the pressure differential across said second burst disk to a level above the second predetermined pressure differential to rupture said second burst disk,

said second burst disk, when unruptured, including a first surface exposed to said inflation fluid and an opposite second surface exposed to said inflation fluid, said first surface and said second surface being in fluid communication when said second burst disk is in an unruptured condition.

20. An apparatus for inflating an inflatable vehicle occupant protection device, said apparatus comprising:

a container defining a gas storage chamber;

inflation fluid under pressure in said gas storage chamber;

a first opening in said container for enabling fluid flow from said gas storage chamber to the inflatable device;

a first burst disk extending across said first opening and being rupturable in response to an increase in the pressure differential across said first burst disk to a level above a first predetermined pressure differential;

first pressurizing means for, when actuated, increasing the pressure differential across said first burst disk to a level above the first predetermined pressure differential to rupture said first burst disk;

a second opening in said container for directing fluid flow from said gas storage chamber to the inflatable device, said second opening being in coaxial alignment with said first opening;

a second burst disk extending across said second opening and being rupturable in response to an increase in the pressure differential across said second burst disk to a second predetermined pressure differential greater than the first differential; and

second pressurizing means actuatable independently of said first pressurizing means for, when actuated, increasing the pressure differential across said second burst disk to a level above the second predetermined pressure differential to rupture said second burst disk.

21. An apparatus for inflating an inflatable vehicle occupant protection device, said apparatus comprising:

a container having an end wall defining a gas storage chamber;

inflation fluid under pressure in said gas storage chamber;

a first opening in said end wall of said container for enabling fluid flow from said gas storage chamber to the inflatable device;

a first burst disk extending across said first opening and being rupturable in response to an increase in the pressure differential across said first burst disk to a level above a first predetermined pressure differential;

first pressurizing means for, when actuated, increasing the pressure differential across said first burst disk to a level above the first predetermined pressure differential to rupture said first burst disk;

a second opening in said end wall of said container for directing fluid flow from said gas storage chamber to the inflatable device, said first opening and said second opening forming parallel paths of flow for said inflation fluid out of said container;

a second burst disk extending across said second opening and being rupturable in response to an increase in the pressure differential across said second burst disk to a second predetermined pressure differential greater than the first differential; and

second pressurizing means actuatable independently of said first pressurizing means for, when actuated, increasing the pressure differential across said second burst disk to a level above the second predetermined pressure differential to rupture said second burst disk.