GAS GENERATOR

• US 3,773,351 A
• Filed: 08/02/1971
• Issued: 11/20/1973
• Est. Priority Date: 08/02/1971
• Status: Expired due to Term

• Current Assignee: HBB Limited Partnership
• Original Assignee: Vincent O. Catanzarite
• Inventors: Catanzarite, Vincent O.
• Primary Examiner(s): Betts, Kenneth H.
• Assistant Examiner(s): Silverstrim, John P.
• Application Number:
  US05/167,944
• Time in Patent Office: 841 Days
• Field of Search: 280/15AB 23/281 102/39
• US Class Current: 280/738
• CPC Class Codes: B60R 21/017 including arrangements for providing electric power to safety arrangements or their actuating means, e.g. to pyrotechnic fuses or electro-mechanic valves
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder
• CPC Class Codes: B60R 21/30 with means to draw ambient air into the flow line and mix such air with the inflation fluid
• 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 low temperature gas generator for inflation of gas bags, particularly useful for passenger restraint in an automobile is provided. An oxidation-reduction pyrotechnic gas producing mixture is hermetically sealed in a chamber prior to initiation, and is ignited by a bridge wire initiator. The pyrotechnic mixture produces a gas comprising principally carbon dioxide and water vapor. Vaporized salts may also be present. These hot gases flow through an array of wires for sound muffling and flame arresting, through a relatively unobstructed passage to a relatively large outlet and into a gas bag for inflation in a very short time interval. Means are provided for inhibiting gas flow rates to less than sonic velocity. Subsequent deflation of the bag occurs upon condensation of water vapor and contraction of carbon dioxide. If desired an aspirator may draw ambient air into the bag with the combustion gases, and when used the aspirator permits reverse flow, giving additional means for deflating the bag. Means are provided for controlling the rate of gas generation and gas temperature for controlled bag deployment and pressurization. A piezoelectric device is provided for firing the bridge wire initiator.

Claims

1. A bag inflation system comprising:

gas generator means comprising a normally solid mixture for oxidation-reduction reaction upon ignition for producing principally water vapor, carbon dioxide and an inorganic salt at a sufficiently high temperature to be principally in a vapor state;

means for initiating deflagration of the mixture in response to a signal;

means for hermetically closing the gas generator means before initiation of deflagration and for freely releasing gas therefrom after iniitiation;

an outlet having a cross-sectional area substantially larger than cross-sectional area of the gas generator means;

means for distributing gas from the gas generator means to the outlet comprising;

a chamber connected to the gas generator means;

a sound baffling array of wires in the chamber, and;

a diverging passage connected along one side of the chamber between the chamber and the outlet, and wherein the chamber comprises a plurality of openings communicating between the interior of the chamber and the passage, the aggregate crosssectional area of the openings being of the same order of magnitude as the cross-sectional area of the gas generaTor, and wherein the diverging passage has a length several times its width in directions transverse to the direction of gas flow; and

means for connecting a gas bag over the outlet.

2. A bag inflation system comprising:

gas generator means comprising a normally solid mixture for oxidation-reduction reaction upon ignition for producing principally water vapor, carbon dioxide and an inorganic salt at a sufficiently high temperature to be principally in a vapor state;

means for initiating deflagration of the mixture in response to a signal;

means for hermetically closing the gas generator means before initiation of deflagration and for freely releasing gas therefrom after iniitiation;

a first outlet having a cross-sectional area of the same order of magnitude as the cross-sectional area of the outlet of the gas generator means;

a first gas flow region comprising a chamber between the gas generator means and the first outlet having an internal volume very much larger than the volume occupied by the mixture;

an array of wires in the first gas flow region between the outlet of the gas generator and the first outlet;

a second outlet downstream from the first outlet having a cross-sectional area substantially larger than cross-sectional area of the gas generator means;

a second gas flow region between the second and first outlets having a gas flow cross-section larger than the cross-sectional area of the first outlet; and

means for connecting a gas bag over the second outlet.

3. A bag inflation system comprising:

gas generator means comprising a normally solid mixture for oxidiation-reduction reaction upon ignition for producing principally water vapor, carbon dioxide and an inorganic salt at a sufficiently high temperature to be principally in a vapor state;

means for initiating deflagration of the mixture in response to a signal;

means for hermetically closing the gas generator means before initiation of deflagration and for freely releasing gas therefrom after initiation;

a system outlet having a cross-sectional area substantially larger than cross-sectional area of the outlet of the gas generator means;

means for connecting a gas bag over the outlet; and

means for distributing gas from the gas generator means to the system outlet; and

wherein the means for distributing comprises a chamber connected to the gas generator means and having an internal volume substantially larger than the volume occupied by the mixture, a gas flow passage from the chamber having a cross-sectional area in the same order as the cross-sectional area of the outlet of the gas generator means and an array of wires in the gas flow region between the outlet of the gas generator and the gas flow passage.

4. A bag inflation system as defined in claim 3 wherein the gas generator means comprises a cup shaped container for the mixture with the open end thereof connected to the chamber;

and wherein the means for initiating deflagration comprises an electrical initiator in the closed end of the container.

5. A gas generator for an automobile passenger restraint system comprising:

a gas generator cartridge having a closed end and an open end;

a gas generating composition in the cartridge;

means at the closed end of the cartridge for igniting the gas generating composition;

a sound baffling array of wires in the flow path of gas from the gas generating composition for causing gas flow to follow a tortuous path;

a plurality of apertures downstream from the array of wires the aggregate cross-sectional area of the apertures being of the same order as the cross-sectional area of the open end of the cartridge; and

a gas passage having a gradually increasing cross-sectional area between the apertures and an outlet over which an inflatable gas bag may be placed.

6. A gas generator as defined in claim 5 wherein the gas generating composition comprises a pyrotechnic deflagration mixtUre for generating a gas comprising principally carbon dioxide, water vapor and vaporized inorganic salt.

7. A gas generator for an automobile passenger restraint system comprising:

a gas generator cartridge having a closed end and an open end;

a gas generating composition in the cartridge;

means at the closed end of the cartridge for igniting the gas generating composition;

a sound baffling array of wires in the flow path of gas from the gas generating composition for causing gas flow to follow a tortuous path;

a plurality of apertures downstream from the array of wires;

a gas passage having a gradually increasing cross-sectional area between the apertures and an outlet over which an inflatable gas bag may be placed; and

means for partially obstructing the gas flow passage between the apertures and the gas bag to have a cross-sectional area in the obstructed region of the same order of magnitude as the aggregate cross sectional area of the apertures.

8. A gas generator for an inflatable bag automobile passenger restraint system comprising:

a generally cylindrical chamber;

a gas generator cartridge connected to one end of the chamber;

a gas generating composition in the cartridge;

means for igniting the gas generating composition;

a sound baffling array of wires in the chamber;

a plurality of apertures along a side wall of the chamber;

a diverging passage having its relatively smaller inlet in fluid communication with the apertures; and

means for connecting a gas bag over the relatively larger outlet of the diverging passage.

9. A system as defined in claim 8 wherein the aggregate cross sectional area of the apertures is substantially the same as the cross-sectional area of the gas generator cartridge.

10. A system as defined in claim 9 wherein the internal volume of the chamber is substantially larger than the internal volume of the gas generator cartridge.

11. A system as defined in claim 8 further comprising an air aspirator having an inlet in fluid communication with ambient air and an outlet adjacent the diverging passage for inducing flow of ambient air into the flow of gas produced by the gas generator.