Wafer grain gas generator

• US 4,890,860 A
• Filed: 01/13/1988
• Issued: 01/02/1990
• Est. Priority Date: 01/13/1988
• Status: Expired due to Term

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Original Assignee: Morton Thiokol, Inc.
• Inventors: Schneiter, Fred E.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Anderson, Andrew J.
• Application Number:
  US07/143,908
• Time in Patent Office: 720 Days
• Field of Search: 422/164, 422/165, 422/166, 422/167, 422/188, 422/218, 422/239, 422/305, 280/728, 280/736, 280/741, 280/742, 29/157 R, 29/446
• US Class Current: 280/741
• CPC Class Codes: B01J 7/00 Apparatus for generating gases production of inert gas mixtures B01J19/14; for generating specific gases, see the relevant subclasses, e.g. C01B, C10J ; in "air bags" on vehicles B60R21/26; for starter gas F02C7/26; blasting cartridges for producing gas under pressure F42B3/04
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder
• CPC Class Codes: Y10T 29/49428 Gas and water specific plumbing component making
• CPC Class Codes: Y10T 29/49863 with prestressing of part

Abstract

A gas generator for automobile gas bags and the like includes a grain wherein a plurality of wafers of combustible gas generating material is arranged in a side by side array and a plurality of meshed cushion members is disposed in alternating relation between the wafers and compressed between the wafers in order to provide improved burn surface neutrality for more uniform inflator gas flow and better utilization of the gas generant, increased retention of solid residue in the combustion chamber for reduced plugging of the gas filters and cleaner inflation gas, a higher volumetric loading fraction so that the size and weight of the inflator may be reduced, and structural suspension of each individual wafer between the adjacent compressed cushion members to reduce breakage and damage of the wafers during the many years the inflator may remain in an automobile.

Claims

1. A gas generator comprising a combustion chamber means, a plurality of wafers of combustible gas generating material disposed within said combustion chamber means and spaced from each other and arranged in a side by side array, a plurality of meshed cushion members disposed in alternating relation between said wafers and compressed between said wafers, means for igniting said wafers, and means for routing generated gas from said combustion chamber means.

2. A gas generator according to claim 1 wherein said combustion chamber means is elongate and has an inner diameter, said igniting means includes an igniter tube which extends longitudinally through said combustion chamber means and is disposed generally concentric therewith and which has an outer diameter, said wafers and said cushion members have the shapes of washers through which said igniter tube is inserted, and each said wafer has an outer diameter equal substantially to said combustion chamber means inner diameter and a central hole diameter equal substantially to said igniter tube outer diameter.

3. A gas generator according to claim 1 wherein said wafers and said cushion members are sized such that the volumetric loading density of said combustion chamber means is at least about 65 percent.

4. A gas generator according to claim 1 wherein said cushion members are composed of screen wire.

5. A gas generator according to claim 4 wherein said screen wire has a size in the range of about 20 to 50 mesh.

6. A gas generator according to claim 4 wherein each said cushion member has a wave configuration.

7. A gas generator according to cushion members have a thickness which about 1.5 and 5 times the thickness of the unwaved screen wire.

8. A gas generator according to claim 7 further comprising a retainer means for compressing said array of wafers and cushion members to structurally suspend each said wafer between compressed respective ones of said cushion members.

9. A gas generator according to claim 8 wherein said combustion chamber means is elongate and has an inner diameter, said igniting means includes an igniter tube which extends longitudinally through said combustion chamber means and is disposed generally concentric therewith and which has an outer diameter, said wafers and said cushion members have the shapes of washers through which said igniter tube is inserted, and each said wafer has an outer diameter equal substantially to said combustion chamber means inner diameter and a central hold diameter equal substantially to said igniter tube outer diameter.

10. A gas generator according to claim 9 wherein said wafers and said cushion members are sized such that the volumetric loading density is at least about 65 percent.

11. A method of assembling a plurality of wafers of combustible gas generating material within a gas generator combustion chamber comprising:

a. disposing the wafers in the combustion chamber in a spaced side-by-side array;

b. disposing meshed cushion members in alternating relation between the wafers; and

c. compressing the array of wafers and cushion members to structurally suspend the wafers spaced from each other between the cushion members.

12. A method according to claim 11 wherein the combustion chamber is elongate and an igniter tube extends longitudinally through and is generally concentric with the combustion chamber, the method further comprising forming the wafers and cushion members in the shape of washers and disposing them in the combustion chamber with the igniter tube inserted therethrough, and sizing the wafers to have an outer diameter equal substantially to the combustion chamber inner diameter and a central hole diameter equal substantially to the igniter tube outer diameter.

13. A method according to claim 11 further comprising sizing the wafers and cushion members to provide a combustion chamber volumetric loading density of at least about 65 percent.

14. A method according to claim 11 further comprising composing the cushion members out of screen wire having a size in the range of about 20 to 50 mesh.

15. A method according to claim 11 further comprising composing the cushion members out of screen wire.

16. A method according to claim 15 further comprising forming the screen wire in a wavy configuration such that the cushion members have a thickness which is between about 1.5 and 5 times the thickness of the unformed screen wire.

17. A method according to claim 15 further comprising forming the screen wire in a wavy configuration.

18. A method according to claim 17 wherein the combustion chamber is elongate and an igniter tube extends longitudinally through and is generally concentric with the combustion chamber, the method further comprising forming the wafers and cushion members in the shape of washers and disposing them in the combustion chamber with the igniter tube inserted therethrough, and sizing the wafers to have an outer diameter equal substantially to the combustion chamber inner diameter and a central hole diameter equal substantially to the igniter tube outer diameter.

19. A method according to claim 18 further comprising sizing the wafers and cushion members to provide a combustion chamber volumetric loading density of at least about 65 percent.

20. An automobile gas bag inflator comprising a combustion chamber means, a plurality of wafers of combustible gas generating material disposed within said combustion chamber means and spaced from each other and arranged in a side by side array, a plurality of meshed cushion members disposed in alternating relation between said wafers and compressed between said wafers, means for igniting said wafers, and means for routing generated gas from said combustion chamber means.