Fluid supply for occupant restraint system

• US 4,116,466 A
• Filed: 08/30/1976
• Issued: 09/26/1978
• Est. Priority Date: 11/29/1974
• Status: Expired due to Term

• Current Assignee: TRW Vehicle Safety Systems Incorporated (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Inventors: Gehrig, Robert G.
• Primary Examiner(s): Silverstrim, John P.
• Application Number:
  US05/718,737
• Time in Patent Office: 757 Days
• Field of Search: 280/741, 280/736, 23/281, 102/39
• US Class Current: 280/736
• CPC Class Codes: B60R 2021/2648 comprising a plurality of combustion chambers or sub-chambers
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder
• CPC Class Codes: F42B 3/04 for producing gas under pressure generators of inflation fluid especially adapted for vehicle air bags B60R21/26

Abstract

A fluid supply is provided for inflating an expandable confinement of a vehicle occupant restraint system of the type activated in response to a vehicle collision signal. The fluid supply includes a housing defining a fluid discharge port for directing fluid flow from the housing and a gas generating material disposed within the housing. The gas generating material includes a sustaining charge comprising a plurality of layers of granulated material, the layers being approximately equal by weight. Screens are disposed between each pair of adjacent layers of the sustaining charge. Each of the screens has a mesh substantially finer than the granules of material in the layer adjacent the screen and oppositely disposed from the fluid discharge port. The sustaining charge is activated in response to a collision signal. Preferably, a filter is included between the fluid discharge port and the layer of granulated material closest thereto and the screens act as intermediate filters to trap any particles of the combustion product which are approximately as large as the original granules, thus preventing too many of these particles from clogging the filter, which would restrict the fluid flow area and cause an undesirable pressure buildup within the housing.

Claims

1. A fluid supply for inflating an expandable confinement of a vehicle occupant restraint system of the type activated in response to a vehicle collision signal, said fluid supply comprising:

(a) housing means defining a fluid discharge port for directing fluid flow from said housing means;

(b) gas generating means disposed within said housing means and including combustible means having

(i) a sustaining charge comprising a plurality of layers of granulated material, said sustaining charge being of the type which, upon combustion, produces solid, porous sinters and fly ash;

(ii) screen means disposed between adjacent layers of said sustaining charge, each of said screen means having a mesh substantially finer than the granules of material in the layer adjacent said screen means and upstream therefrom, each of said screen means permitting gas to pass freely therethrough and retaining said sinters upstream therefrom, said retained sinters being effective for permitting said generated gas to pass therethrough while simultaneously filtering said fly ash; and

(c) means operable to activate said sustaining charge in response to said collision signal.

2. A fluid supply as defined in claim 1 wherein said sustaining charge comprises first, second and third layers of granulated material, and said screen means includes a first screen disposed between said first and second layers and a second screen disposed between said second and third layers.

3. A fluid supply as defined in claim 2 wherein said first layer is disposed adjacent said charge activating means, said third layer is disposed adjacent said fluid discharge port and said second layer is disposed between said first and third layers.

4. A fluid supply as defined in claim 3 including filter means disposed between said fluid discharge port and said third layer.

5. A fluid supply as defined in claim 1 wherein said plurality of layers of granulated material have a generally common granule size.

6. A fluid supply as defined in claim 5 wherein said plurality of layers comprise granules in the range of 6-8 mesh.

7. A fluid supply as defined in claim 1 including at least three layers of granulated material and at least a pair of screens, said screens having a generally common mesh size.

8. A fluid supply as defined in claim 7 wherein said screens have a mesh size in the range of 60-100.

9. A fluid supply as defined in claim 1 wherein said sustaining charge includes sodium azide.

10. A fluid supply as defined in claim 1 wherein the layer of granulated material remote from said fluid discharge port includes material having a first burn rate with a portion thereof being formed of material having a second burn rate, said second burn rate being faster than said first burn rate.

11. A fluid supply as defined in claim 1 wherein said charge activating means includes a booster charge disposed within said housing means oppositely from said fluid discharge port, and means for initiating combustion of said booster charge.

12. A fluid supply as defined in claim 11 wherein said booster charge comprises less than about 10 percent by weight of said combustible means and comprises granules of material having sizes in the range of 10-35 mesh.

13. A fluid supply as defined in claim 11 wherein said booster charge comprises from about 3 to about 4 percent by weight of said combustible means and includes potassium perchlorate.

14. A fluid supply as defined in claim 1 wherein said granulated material in said sustaining charge is of the type which, upon combustion, comprises solid, porous sinters.

15. A fluid supply for inflating an expandable confinement of a vehicle occupant restraint system of the type activated in response to a vehicle collision signal, said fluid supply comprising:

(a) housing means defining a fluid discharge port for directing fluid flow from said housing means;

(b) gas generating means disposed within said housing means and including combustible means having,

(i) a sustaining charge comprising first, second, and third layers of granulated material having granules in the range of 8-14 mesh, 6-8 mesh, and 4-6 mesh, respectively;

(ii) screen means disposed between adjacent layers of said sutaining charge, said screen means includes a first screen disposed between said first and second layers, and a second screen disposed between said second and third layers, each of said screen means having a mesh substantially finer than the granules of material in the layer adjacent said screen means and upstream therefrom; and

(c) means operable to activate said sustaining charge in response to said collision signal.

16. A fluid supply as defined in claim 15 wherein said first and second screens have a mesh sized in the range of 60-100.

17. A fluid supply for an expandable confinement of a vehicle occupant restraint system, said fluid supply being operable in response to an activating means and comprising:

(a) housing means defining a fluid discharge port operable to direct fluid flow from said housing means;

(b) gas generating means disposed within said housing means;

(c) filter means disposed downstream from said gas generating means and adjacent said fluid discharge port;

(d) said gas generating means including a sustaining charge of the type which, upon combustion, produces solid, porous sinters and fly ash, said sustaining charge comprising a first layer of granulated material adjacent said filter means, a second layer of granulated material upstream from said first layer and a third layer of granulated material upstream from said second layer, said first, second and third layers comprising granules in the range of about 4 to 14 mesh; and

(e) a first layer of screen disposed between said first and second layers of granulated material and a second layer of screen disposed between said second and third layers of granulated material, said first and second layers of screen having a mesh size in the range of about 60-100, each of said screen means permitting gas to pass freely therethrough and retaining said sinters upstream therefrom, said retained sinters effective for permitting said generated gas to pass therethrough while simultaneously filtering said fly ash.

18. A fluid supply as defined in claim 17 wherein said granulated material comprising third layer has a first burn rate, said third layer having a portion thereof containing a combustible material having a second burn rate faster than said first burn rate.

19. A fluid supply as defined in claim 17, wherein said third layer of granulated material includes potassium perchlorate.