Method of assembling a hybrid inflator

• US 5,679,915 A
• Filed: 11/03/1995
• Issued: 10/21/1997
• Est. Priority Date: 03/18/1994
• Status: Expired due to Term

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Original Assignee: OEA Incorporated (Autoliv Incorporated)
• Inventors: Hamilton, Brian K., Baglini, James L.
• Primary Examiner(s): Nelson, Peter A.
• Application Number:
  US08/552,861
• Time in Patent Office: 718 Days
• Field of Search: 102/288, 102/289, 86/20.1, 86/21
• US Class Current: 86/20.1
• 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: C06B 45/10 the organic component containing a resin
• CPC Class Codes: C06D 5/00 Generation of pressure gas, e.g. for blasting cartridges, starting cartridges, rockets explosive compositions containing an oxidizer, fuels for rocket engines intended for reaction with an oxidant other than air C06B
• CPC Class Codes: C06D 5/06 by reaction of two or more solids
• CPC Class Codes: C06D 5/10 by reaction of solids with liquids

Abstract

A hybrid inflator for an automotive inflatable safety system and method for assembling the same. In one embodiment, a mixture of an inert gas (e.g., argon) and oxygen are contained within the inflator housing and a gun type propellant is used in the gas generator to supply the propellant gases.

Claims

1. A method for assembling an inflator for an inflatable safety system comprising an air/safety bag, said inflator comprising an inflator housing, a gas generator, and an inflator activation assembly, said method comprising the steps of:

positioning a solid gun type propellant inside said gas generator, wherein combustion of said solid gun type propellant augments a flow to the air/safety bag and wherein exposure of said gun type propellant to a temperature of 107 degrees for a period of 400 hours does not degrade said gun type propellant substantially in relation to its suitability for use in said inflator, and thereafter said gun type propellant will ignite when exposed to an autoignition temperature of said gun type propellant;

positioning said gas generator inside said inflator housing;

interconnecting said gas generator and said inflator housing;

interconnecting said inflator activation assembly with said inflator housing, said activation assembly comprising an ignitable material other than said gun type propellant;

introducing a first gas into at least said inflator housing;

introducing a second gas into at least said inflator housing which is different from said first gas, wherein said first and second gases consist essentially of an inert gas and oxygen, respectively; and

sealing said inflator housing to substantially retain said first and second gases within said inflator housing, wherein after said sealing step and prior to any activation of said inflator activation assembly, said first and second gases are the only gases contained within said inflator housing and define a pressurized medium.

2. A method, as claimed in claim 1, wherein:

said positioning a gun type propellant step comprises positioning from about 10 grams to about 12 grams of said gun type propellant within said gas generator.

3. A method, as claimed in claim 1, wherein:

said positioning a gun propellant step comprises positioning less that about 15 grams of said gun type propellant within said gas generator.

4. A method, as claimed in claim 2, wherein:

said method further comprises the step of pressurizing said inflator housing with an amount of said first and second gases ranging from about 150 grams to about 190 grams using said introducing a first gas and introducing a second gas steps.

5. A method, as claimed in claim 1, wherein:

said method further comprises the step of selecting an amount of said pressurized medium for said introducing first and second gases steps and selecting an amount of said gun type propellant for said positioning step, whereby a ratio of a weight of said pressurized medium to a weight of said gun type propellant is within at least one of first and second ranges, said first range being from about 14 to about 18 and said second range being greater than about 15.

6. A method, as claimed in claim 5, wherein:

said selecting step comprises selecting a gun type propellant having a composition, on a weight percentage basis, of about 76.0% hexahydrotrinitrotriazine, about 12.0% percent cellulose acetate butyrate, about 4.0% nitrocellulose of which about 12.6% is nitrogen, about 7.60% acetyl triethyl citrate, and about 0.4% ethyl centralite.

7. A method, as claimed in claim 1, wherein:

said first gas is argon and said second gas is oxygen, said first and second gases are a pressurized medium, said introducing a first gas step comprises, on a molar basis, introducing about 70% to about 90% of said pressurized medium with said argon, and said introducing a second gas step comprises, on a molar basis, introducing about 10% to about 30% of said pressurized medium with said oxygen.