Initiator and method for the incorporation thereof in an inflator

• US 4,722,551 A
• Filed: 03/19/1987
• Issued: 02/02/1988
• Est. Priority Date: 03/19/1987
• Status: Expired due to Term

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Original Assignee: Morton-Thiokol, Inc. (Howmet Aerospace, Inc.)
• Inventors: Adams, Gary V.
• Primary Examiner(s): BERTSCH, RICHARD A
• Application Number:
  US07/027,917
• Time in Patent Office: 320 Days
• Field of Search: 280/731, 280/732, 280/734, 280/736, 180/282, 422/166
• US Class Current: 280/736
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder

Abstract

An inflator for a protective air bag is arranged for initiation by an ignition squib assembly that is adapted to be incorporated in the inflator housing structure after assembly thereof with the inflator pyrotechnics contained therein. The ignition squib assembly includes a sleeve having a circular crimp on a first end region thereof with a collar on the sleeve in tight embracing relation with that region. Igniting materials including an electrical squib and ferrite beads are potted in the sleeve. The sleeve and attached collar are pressed in a hole in the wall of the housing structure defining the inflator ignition chamber with a second end region of the sleeve extending into the ignition chamber and an inner end of the collar abutting an O-ring in the hole to provide a seal. A lip on the hole is rolled over the collar to prevent the ignition squib assembly from being pulled out of the hole.

Claims

1. A method for incorporating an initiator in the housing structure of an inflator having an ignition chamber after assembly of the housing structure with the inflator pyrotechnics contained therein comprising the steps of:

(a) forming a hole in the wall of said inflator ignition chamber with said hole having a first inner shoulder and an external lip;

(b) placing an O-ring in said hole in engaging relationship with said inner shoulder;

(c) forming an initiator for press fit insertion into said hole by;

(1) placing a collar having an inner end and an outer end on a first end portion of a sleeve, said sleeve also having a second end portion and having a circular crimp on said first end portion, said collar having an inner shoulder adjacent said outer end thereof against which the end of said sleeve adjacent said first end portion is positioned in abutting relation;

(2) expanding said sleeve into said collar to effect a tight attachment of said collar on said sleeve;

(3) placing igniting materials including an electric squib having a pair of energizing terminals in said sleeve; and

(4) potting said igniting materials in said sleeve with the said energizing terminals of said electric squib extending outwardly from the end of said first end portion of said sleeve;

(d) incorporating in the housing structure of the inflator said initiator so formed in accordance with step (c) by;

(1) pressing said sleeve and collar in said hole in the wall of said inflator ignition chamber with the inner end of said collar bearing against said O-ring therein thereby to effect a seal for said ignition chamber; and

(2) rolling the external lip of said hole over the outer end of said collar to prevent said collar and sleeve from being pulled out of said hole.

2. A method as defined by claim 1 including the further step in the formation of said hole in the wall of the inflator ignition chamber of forming a second inner shoulder therein positioned between said lip and said first inner shoulder;

and

including the further step in the formation of said initiator for press fit insertion into said hole of forming said collar with an external shoulder adjacent said outer end thereof;

whereby when said lip is rolled over said collar said external shoulder of said collar is captured between said lip and said second inner shoulder of said hole.

3. A method as defined by claim 2 including the further step in the formation of said initiator of forming said sleeve

with at least three substantially straight longitudinal ridges that are substantially equally angularly spaced about the peripheral surface thereof for guiding said sleeve and collar as they are being pressed in said hole, said ridges being located at a central region along the length of said sleeve between the second end of said collar and the second end portion of said sleeve.

4. An ignition squib assembly comprising,

a sleeve having a first end and a second end and including a circular crimp adjacent said first end, the extreme end of said first end of said sleeve being planar, and

a collar having a planar inner shoulder adjacent one end thereof, said collar being held in tight embracing relationship with said first end at least of said sleeve including said crimp with the planar end of said first end of said sleeve in abutting relation with said planar inner shoulder of said collar,

said sleeve having igniting materials therein including an electrical squib having electrical terminals that extend outwardly of said sleeve from said first end thereof, said igniting materials being potted in said sleeve with a suitable potting material.

5. An igniting squib assembly as defined by claim 4 wherein said collar is held tightly attached to said sleeve as a result of said sleeve having been expanded thereinto.

6. An ignition squib assembly as defined by claim 4 wherein said collar further includes an external shoulder adjacent said one end thereof.

7. An ignition squib assembly as defined by claim 4 wherein said sleeve further includes at least three substantially straight longitudinal ridges that are substantially equally angularly spaced about the surface thereof, said longitudinal ridges being located at a central region along the length of said sleeve between said collar and the second end of said sleeve.

8. An ignition squib assembly as defined by claim 4 wherein said sleeve is steel plated and said collar is made of stainless steel.

9. An ignition squib assembly comprising,

a sleeve having a first end and a second end and including a circular crimp adjacent said first end, the extreme end of said first end of said sleeve being planar, said sleeve being made of a steel plated material, and

a collar having a planar inner shoulder adjacent one end thereof, said collar being held in tight embracing relationship with said first end of said sleeve including said crimp with the planar end of said first end of said sleeve in abutting relation with said planar inner shoulder of said collar, said collar having an external shoulder adjacent said one end thereof,

said sleeve having igniting materials therein including an electrical squib having electrical terminals that extend outwardly of said sleeve from said first end thereof, said igniting materials being potted in said sleeve with a suitable potting material,

said sleeve further including at least three substantially straight longitudinal ridges that are substantially equally angularly spaced about the surface thereof, said longitudinal ridges being located at a central region along the length of said sleeve between said collar and the second end of said sleeve.