Air bag cushion retention method

• US 5,634,658 A
• Filed: 03/05/1996
• Issued: 06/03/1997
• Est. Priority Date: 05/17/1993
• Status: Expired due to Term

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Original Assignee: Morton International Incorporated (Autoliv Incorporated)
• Inventors: Adams, Gary V.
• Primary Examiner(s): Culbreth, Eric D.
• Application Number:
  US08/610,899
• Time in Patent Office: 455 Days
• Field of Search: 280/728.1, 280/728.2, 280/743.1, 280/731, 280/732
• US Class Current: 280/728.2
• CPC Class Codes: B60R 21/217 Inflation fluid source retainers, e.g. reaction canisters; Connection of bags, covers, diffusers or inflation fluid sources therewith or together

Abstract

A vehicle occupant air bag module safety apparatus includes an inflatable air bag cushion, an inflator for inflating the air bag cushion, and a module housing or mounting plate for supporting the air bag cushion and the inflator on a steering wheel. For securing the air bag cushion to the inflator and the module housing or mounting plate an annular portion of the air bag cushion adjacent the gas inlet opening thereof is clamped between a curved annular portion of the module housing or mounting plate adjacent an opening therein and the adjacent lower side of the inflator flange and the inflator lower wall portion including a merging annular region of the inflator lower wall portion and the inflator flange lower side.

Claims

1. A method of securing an inflatable cushion to an air bag module, which air bag module consists of a supporting plate and a generally annular inflator having an upper wall portion and a lower wall portion and an intermediately positioned flange having a lower facing side and with an upper wall portion including ports from which cushion inflating gas issues when the inflator is initiated, the lower wall portion including a curved merging region adjacent said lower facing side of said flange, and the flange having a plurality of spaced fastener holes therein, comprising the steps of:

(a) forming a generally circular gas inlet opening in the inflatable cushion having a diameter that is slightly less than the diameter of the inflator lower wall portion,

(b) forming an opening in the supporting plate the diameter of which opening is larger than the diameter of the inflator lower wall portion and the edge of which opening includes a downwardly curved portion that matches the curvature of the merging region of the inflator lower wall portion adjacent said lower facing side of said flange, the amount by which the diameter of the opening in the supporting plate is larger than the diameter of the inflator lower wall portion being sufficient to allow the insertion therebetween of an annular portion of said inflatable cushion adjacent the inflatable cushion gas inlet opening,

(c) inserting and clinching a plurality of studs into the spaced fastener holes of the inflator flange from the side thereof adjacent the inflator upper wall portion,

(d) inserting the inflator upper wall portion and the flange into the gas inlet opening in the inflatable cushion and positioning the inflator such that an annular portion of the cushion adjacent the edge of the gas inlet opening is wrapped around and lies inward of and beyond said flange, and is positioned to be clamped around the curvature of the opening of said supporting plate and around the lower wall portion of said inflator,

(e) extending each of the studs through a hole individual thereto that is provided in the material of the inflatable cushion in an annular region surrounding the gas inlet opening therein, with each of the holes in the material of the inflatable cushion positioned to allow a distance beyond said flange at which the gas inlet opening lies to provide an area of the inflatable cushion annular portion adjacent the gas inlet opening that can be clamped, with the force holding the gas inlet opening of the cushion to the supporting plate and inflator evenly distributed over the clamped annular portion of the cushion,

(f) inserting the inflator lower wall portion and the annular portion of the inflatable cushion adjacent the gas inlet opening into the opening in the supporting plate and extending each of the studs through a hole individual thereto that is provided therein in an annular region adjacent the opening in the supporting plate, and

(g) providing nuts on the studs and tightening them to clamp the annular portion of the inflatable cushion adjacent the gas inlet opening between the curved annular portion of the supporting plate adjacent the opening therein against the adjacent side of the inflator flange and the inflator lower wall portion including the merging region of said inflator wall portion and flange.

2. A method as defined by claim 1 including the further step between steps (f) and (g) of

(h) folding back the edge of the inflatable cushion at the edge of the gas inlet opening to increase the thickness of the inflatable cushion material in the annular space between the inflator lower wall portion and the opening in the supporting plate.

3. A method as defined by claim 1 wherein the supporting plate comprises a module housing.

4. A vehicle occupant air bag module safety apparatus comprising,

an inflatable air bag cushion having a generally circular gas inlet opening and having a plurality of spaced holes in an annular region surrounding said gas inlet opening,

an inflator for inflating the air bag cushion, said inflator having a general annular configuration with an upper wall portion having generated gas exit ports therein, a lower wall portion, and an intermediately positioned flange having a lower facing side adjacent said lower wall portion of said inflator, with the diameter, at least, of said inflator lower wall portion being slightly greater than that of said air bag cushion gas inlet opening, said inflator lower wall portion including a curved annular merging region with the adjacent side of said inflator flange, said inflator flange including a plurality of spaced holes therein,

a support plate, said support plate having an opening therein that is larger than that of the inflator lower wall portion and including a downwardly curved annular portion that matches the curvature of the merging annular region of the inflator lower wall portion and the flange, the amount by which the opening in the supporting plate is larger than the inflator lower wall portion being sufficient to allow the insertion therebetween of an annular portion of the inflatable cushion adjacent the inflatable cushion gas inlet opening, said support plate having a plurality of spaced holes in an annular region surrounding said opening therein, and

a stud clinched in each of said plurality of spaced holes in said inflator flange from the side thereof adjacent said inflator upper portion,

said inflator upper portion and flange being inserted in said air bag cushion gas inlet opening and positioned such that an annular portion of the cushion adjacent the edge of the gas inlet opening is wrapped around and lies inwardly of and beyond the inflator flange and positioned to be clamped around the curvature of the opening of said support plate and around the lower wall portion of said inflator, with each of said studs extending through a hole individual thereto of said plurality of holes in said annular region surrounding said cushion gas inlet opening, with each of the holes in said cushion positioned to allow a distance beyond the inflator flange at which the gas inlet opening lies to provide an area of the annular portion of the cushion adjacent the cushion gas inlet opening that can be clamped with the force holding the gas inlet opening of the cushion to the support plate and inflator evenly distributed over the clamped annular portion of the cushion,

said inflator lower wall portion and the annular portion of said air bag cushion adjacent the gas inlet opening therein being inserted through the opening of said support plate with each of said studs extending through a hole individual thereto in said support plate in said annular region adjacent the opening therein, and

a nut provided on each of said studs and tightened to clamp the annular portion of the inflatable cushion adjacent the gas inlet opening between the curved annular portion of the supporting plate adjacent the opening therein and the adjacent side of the inflator flange and the inflator lower wall portion including the curved merging annular region of the inflator well portion and flange,

whereby there is provided an improvement in the seal of the gas inlet opening of the air bag cushion of the air bag module.

5. A vehicle occupant air bag module safety apparatus as defined by claim 4 wherein the supporting plate comprises a module housing.

6. A vehicle occupant air bag module safety apparatus as defined by claim 5 wherein the module housing has a dish shaped configuration and includes an upper edge that is curved outwardly to form a rolled-over lip, and

wherein there is further included a cover for said air bag cushion, said inflator and said module housing, said cover having a wall with a groove formed on the inner side thereof,

said rolled-over lip on the upper edge of said module housing engaging and being locked in mating relation with said groove in said wall of said cover when the folded air bag cushion and module housing are pressed in place within the cover.