Inflator for inflatable restraint

• US 6,224,097 B1
• Filed: 08/29/2000
• Issued: 05/01/2001
• Est. Priority Date: 12/22/1995
• Status: Expired due to Term

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Universal Propulsion Company Incorporated (Rtx Corporation)
• Inventors: Lewis, Donald J.
• Primary Examiner(s): English, Peter C.
• Application Number:
  US09/649,950
• Time in Patent Office: 245 Days
• Field of Search: 280/737, 280/736, 280/741, 137/68.13, 102/530, 102/531
• US Class Current: 280/737
• CPC Class Codes: B60R 21/18 the inflatable member formed as a belt or harness or combined with a belt or harness arrangement
• 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: 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

Abstract

The invention is directed to an inflator device and a method of inflating an inflatable member. The inflator device is adapted for producing a sufficient quantity of a gaseous product to substantially inflate the inflatable member operatively associated therewith without substantial heating of the device or the member. The device has a housing that defines an interior volume, and contains a pressurized gas at a first pressure in the interior volume. The housing also has a member for maintaining the pressurized gas at the first pressure within the interior volume and for opening when the gas attains a predetermined second, higher pressure upon combustion of a pyrotechnic material within the housing to allow the gas to pass from the housing. The pyrotechnic material is stored within a container within the interior volume of the housing. At least a portion of the pyrotechnic material, upon combustion, exits the container, and generates heat and combustion products within the pressurized gas. Because the first pressure is sufficiently high and the pyrotechnic material has a burning time that is sufficiently short, upon combustion, the pyrotechnic material burns substantially completely without substantial contact of burning material upon the inner surface of the housing, such that the heat generated by the combustion of the pyrotechnic material is transferred directly and thermally to the pressurized gas without substantial transfer of heat to the housing, thereby heating the pressurized gas at the first pressure, increasing the gas pressure to at least the second, higher pressure to cause the pressure maintaining member to open and the gas to exit the interior volume without substantial heating of the inflator device.

Claims

1. An inflator device adapted for producing a sufficient quantity of a gaseous product to substantially inflate an inflatable member operatively associated therewith without substantial heating of the device or the member, the device comprising:

a housing, defining an interior volume, and having an inner surface, the housing containing a pressurized gas at a first pressure in the interior volume,

means for maintaining the pressurized gas at the First pressure within the interior volume and for opening when the gas attains a predetermined second, higher pressure upon combustion of a pyrotechnic material within the housing to allow the gas to pass from the housing;

a container within the interior volume of the housing, having stored therein a quantity of the pyrotechnic material, at least a portion of which, upon combustion, exits the container, and generates heat and combustion products within the pressurized gas; and

an ignitor in thermal contact with the pyrotechnic material, the ignitor including a pyrotechnic firing compound, which, upon combustion thereof, transfers heat to the pyrotechnic material, which, in turn, causes the combustion of the pyrotechnic material, wherein

the first pressure is sufficiently high and the pyrotechnic material has a burning time that is sufficiently short, such that, upon combustion, the pyrotechnic material burns substantially completely without substantial contact of burning material upon the inner surface of the housing, such that substantially all of the heat generated by the combustion of the pyrotechnic material is transferred directly and thermally to the pressurized gas without substantial transfer of heat to the housing, thereby heating the pressurized gas at the first pressure, increasing the gas pressure to at least the second, higher pressure to cause the pressure maintaining means to open and the gas to exit the interior volume without substantial heating of the inflator device.

2. The inflator device of claim 1, wherein the burning time is sufficiently short, such that combustion products exit the container in no more than about 1 ms.

3. The inflator device of claim 1, wherein the burning time of the pyrotechnic material is no more than about 5 ms.

4. The inflator device of claim 1, wherein the pyrotechnic material is present in an amount at least sufficient to provide a gas pressure during combustion of about 12,000 psi.

5. The inflator device of claim 1, wherein the pressure maintaining means is a rupturable diaphragm.

6. The inflator device of claim 1, wherein the second pressure is about 12,000 psi.

7. The inflator device of claim 1, wherein the burning time is sufficiently short, such that the pressurized gas exits the housing in no more than about 10 ms.

8. The inflator device of claim 1, wherein the inflatable member has an initial temperature before inflation and a final temperature after inflation, and the final temperature is no more than about 7°

F. higher than the initial temperature.

9. The inflator device of claim 1, wherein the pyrotechnic material is in the form of particles.

10. A method of inflating an inflatable member with an inflator device without substantial heating of the device or the inflatable member, the method comprising:

providing an inflator device comprising a housing defining a first interior volume, and having an inner surface, the housing containing a pressurized gas at a first pressure in the interior volume, and means for maintaining the pressurized gas at the first pressure within the interior volume and for opening when the gas attains a predetermined second higher pressure upon combustion of a pyrotechnic material within the housing to allow the gas to pass from the housing;

storing the pyrotechnic material in a container within the housing;

initiating an ignitor in thermal contact with the pyrotechnic material, the ignitor including a pyrotechnic firing compound that, upon combustion thereof, transfers heat to the pyrotechnic material, which, in turn, causes combustion of the pyrotechnic material, at least a portion of which, upon combustion, exits the container, and generates heat and combustion products within the pressurized gas;

wherein the first pressure is sufficiently high and the pyrotechnic material has a burning time that is sufficiently short, such that, upon combustion, the pyrotechnic material burns substantially completely without substantial contact of burning material upon the inner surface of the housing;

directly and thermally transferring substantially all of the heat from the combustion of the pyrotechnic material to the pressurized gas without substantial transfer of heat to the housing to heat the pressurized gas at the first pressure, and increase the gas pressure to at least the second, higher pressure to cause the pressure maintaining means to open and the gas to exit the interior volume; and

passing at least a portion of the gas from the inflator device into an inflatable member, thereby inflating the inflatable member without substantial heating of the inflator device or the inflatable member.

11. The method of claim 10, further comprising burning the pyrotechnic material in a time sufficiently short for the pressurized gas to exit the housing in no more than about 10 ms.

12. The method of claim 10, further comprising burning the pyrotechnic material in a time sufficiently short for combustion products to exit the container no more than about 1 ms after initiating the ignitor.

13. The method of claim 10, further comprising opening the pressure maintaining means by rupturing a rupturable diaphragm.

14. The method of claim 10, further comprising opening the pressure maintaining means at a pressure of about 12,000 psi.

15. The method of claim 10, further comprising combusting the pyrotechnic material in a burning time of no more than about 5 ms.

16. The method of claim 10, further comprising subjecting the inflatable member to a temperature increase of no more than about 7°

F. during inflation.

17. A method of inflating an inflatable member with an inflator device without substantial heating of the device or the inflatable member, the method comprising:

providing an inflator device comprising a housing defining a first interior volume, and having an inner surface, the housing containing a pressurized gas at a first pressure in the interior volume, and means for maintaining the pressurized gas at the first pressure within the interior volume and for opening when the gas attains a predetermined second higher pressure upon combustion of a pyrotechnic material within the housing to allow the gas to pass from the housing in no more than about 10 ms;

storing the pyrotechnic material in a container within the housing;

initiating an ignitor in thermal contact with the pyrotechnic material, the ignitor including a pyrotechnic firing compound that, upon combustion thereof, transfers heat to the pyrotechnic material, which, in turn, causes combustion of the pyrotechnic material, at least a portion of which, upon combustion, exits the container in no more than about 1 ms after initiating the ignitor, and generates heat and combustion products within the pressurized gas;

wherein

the first pressure is sufficiently high and the pyrotechnic material has a burning time of no more than about 5 ms, such that, upon combustion, the pyrotechnic material burns substantially completely without substantial contact of burning material upon the inner surface of the housing;

directly and thermally transferring substantially all of the heat from the combustion of the pyrotechnic material to the pressurized gas without substantial transfer of heat to the housing to heat the pressurized gas at the first pressure, and increase the gas pressure to at least the second, higher pressure to cause the pressure maintaining means to open and the gas to exit the interior volume; and

passing at least a portion of the gas from the inflator device into an inflatable member, thereby inflating the inflatable member without substantial heating of the inflator device or the inflatable member.