Ignition delay module for an airbag inflator

• US 7,887,090 B2
• Filed: 07/17/2007
• Issued: 02/15/2011
• Est. Priority Date: 07/17/2007
• Status: Expired due to Fees

• Current Assignee: Key Safety Systems, Inc. (Ningbo Junsheng Investment Group Co., Ltd.)
• Original Assignee: Key Safety Systems, Inc. (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Trevillyan, Dennis A.
• Primary Examiner(s): Chambers; Troy
• Application Number:
  US11/778,847
• Publication Number:
  US 20090020032A1
• Time in Patent Office: 1,309 Days
• Field of Search: 102/286, 102/288, 102/289, 102/290, 280/741
• US Class Current: 280/741
• 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
• CPC Class Codes: F42C 9/10 the timing being caused by combustion F42C9/14 takes precedence

Abstract

An ignition delay module (10) for use in an airbag inflator (100, 200) has an ignition delay module housing (11). The ignition delay module (10) separates the inflator (100, 200) into two chambers (40, 60). A pyrotechnic tablet (2) is positioned inside the ignition delay module housing (11). Upon activation of the inflator (100, 200) the ignition delay module (10) prevents a gas generant (62) in a second chamber (60) of the inflator (100, 200) from igniting until at least a portion of the pyrotechnic tablet (2) is burnt. Preferably a burn inhibitor layer (3) is affixed or otherwise applied to a surface of the pyrotechnic tablet (2). The ignition delay module housing (11) has a first end with a plurality of openings (7) and a second end with openings (20) blocked by the pyrotechnic tablet (2) at the burn inhibitor layer (3) such that upon an ignition of a gas generant (42) in the first inflator chamber (40), the burn inhibitor layer (3) is overcome and the pyrotechnic tablet (2) is ignited and burns to expose the openings (20) in the second end of the ignition delay module housing (11) causing a time delay before igniting a gas generant (62) in the second chamber (60). The ignition delay module (10) is usable in either a pyrotechnic inflator (100) or a hybrid inflator (200).

Claims

1. An ignition delay module for an airbag inflator comprising:

an ignition delay module housing positioned inside the inflator separating the inflator into a first portion and a second portion; and

a pyrotechnic tablet positioned inside the ignition delay module housing;

wherein upon igniting the inflator the first portion ignites while the ignition delay module prevents the second portion of the inflator from igniting until at least a portion of the pyrotechnic tablet is burnt.

2. The ignition delay module for an airbag inflator of claim 1 further comprising a burn inhibitor layer on a surface of the pyrotechnic tablet.

3. An ignition delay module for an airbag inflator comprising:

an ignition delay module housing;

a pyrotechnic tablet, a burn inhibitor layer on a surface of the pyrotechnic tablet positioned inside the ignition delay module housing;

wherein upon igniting the inflator, the ignition delay module prevents a second portion of the inflator to ignite until at least a portion of the pyrotechnic tablet is burnt; and

wherein the ignition delay module housing when placed in the inflator separates the inflator into two chambers, the ignition delay module housing having a first end with a plurality of openings and a second end with a plurality of openings blocked by the pyrotechnic tablet at the burn inhibitor layer surface.

4. An ignition delay module for an airbag inflator positioned between a first inflator chamber and a second inflator chamber, each chamber having a gas generant contained therein, the ignition delay module comprising:

an ignition delay module housing, the ignition delay module housing having a first end and a second end and a spaced therebetween the two ends defining a delay chamber,

a pyrotechnic tablet held inside the delay chamber, and

wherein the first end has a plurality of openings unobstructed by the pyrotechnic tablet and said second end has a plurality of openings obstructed by a surface of the pyrotechnic tablet, the surface of the pyrotechnic tablet having a burn inhibitor layer that upon an ignition of the gas generant in the first inflator chamber, the pyrotechnic tablet is ignited and burns with the burn inhibitor layer to expose the openings in the second end causing a time delay before igniting gas generant in the second chamber.

5. An airbag inflator comprising:

an inflator housing;

an igniter fitted to the inflator housing;

a gas generating material located within the inflator housing;

an ignition delay module located in the inflator housing and having an ignition delay module housing separating the gas generating material into a first quantity and second quantity; and

a pyrotechnic tablet located in the ignition delay module housing and having one surface with a burn inhibitor layer thereon;

wherein the ignition delay module housing has a first end and second end each end having a plurality of openings, the opening on the first end being unobstructed while the pyrotechnic tablet has the surface with a burn inhibitor covering the openings of the second end to create a delay in igniting the second quantity of gas generating material when the igniter is activated.

6. The airbag inflator of claim 5 wherein the inflator is a pyrotechnic inflator.

7. The airbag inflator of claim 5 wherein the inflator is a hybrid inflator containing an inert gas under pressure and the gas generant separated into the first and the second quantities.

8. An airbag inflator comprising:

an inflator housing;

an igniter fitted to the inflator housing;

a first quantity of a gas generant disposed inside the inflator housing when ignited by the igniter, the inflator housing having openings therethrough that allow gas generated by the first quantity of gas generant escape from the inflator housing;

a second quantity of a gas generant disposed inside the inflator housing, the inflator housing having openings therethrough that allow gas generated by the second quantity of a gas generant when burned to escape from the inflator housing;

an ignition delay module disposed within the inflator housing and separating the first quantity of gas generant from the second quantity of gas generant, the ignition delay module comprising an ignition delay module housing having first openings therethrough that communicate with the first quantity of gas generant and second openings therethrough that communicate with the second quantity of gas generant, the ignition delay module housing containing a body comprising a pyrotechnic substance, the body having a surface that is coated with a burn inhibitor layer and the burn inhibitor layer is positioned to completely cover the second openings in the ignition delay module housing while the first openings in the ignition delay module housing are not completely obstructed, the first openings in the ignition delay module housing allow gas generated by the burning of the first quantity of gas generant to enter the ignition delay module housing and ignite the body comprising a pyrotechnic substance, the burning of the body comprising a pyrotechnic substance generating sufficient heat to deteriorate the burn inhibitor layer allowing gas to communicate with and ignite the second first quantity of gas generant.