Aspirating/venting air bag module assembly

An airbag module adapted for installation within an automobile steering wheel, said modular comprising:

• (a) a mounting plate for securing a pyrotechnic inflator device within said module, said mounting plate formed of a metal stamping comprising an open pan having, in series, a first, a second and a third stepped level extending rearwardly thereon, each said level having a substantially unvarying depth at any point thereon and positioned directly over a next rearward one of said levels, said levels correspondingly decreasing in volume from said first to said third level, wherein said first and said second levels each comprise a base and an integral peripheral wall portion formed substantially perpendicular thereto, each said peripheral wall extending entirely around said corresponding level and having a substantially unvarying width, said third level comprising an outer peripheral wall portion formed integral with and substantially perpendicular to said base of said second stepped level and, extending rearwardly from said peripheral wall defining said third level, a metal skirt configured and adapted for locking engagement with a conduit extending rearwardly therefrom to at least a corresponding aperture defined within a firewall portion of said automobile, said conduit configured and adapted for permitting a reciprocal fluid flow between an inflatable air cushion operatively associated with said module and the atmosphere external to said automobile;
• (b) a plurality of radially projecting members formed integral with a lower surface of said mounting means adjacent said second and said third stepped levels, each said projecting member comprising
• (i) a pair of opposed planar side walls, each said side wall having a first axial and a first radial side and a second axial and a second radial side such that said first axial side of each said wall is formed integral with a portion of said outer peripheral wall of said third stepped level adjacent a corresponding gas passage aperture defined thereby and said first radial side of each said wall is formed integrally with said base portion of said second stepped level;
• (ii) a floor member extending substantially perpendicularly from said third stepped level, rearwardly of said gas passage aperture and formed integral with said peripheral wall of said third level, said floor member having first and second longitudinal side edge portions wherein said first side edge is formed integral with said second radial side of one said wall and said second side edge is formed integral with said second radial side of said other wall;
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• (iii) an axially extending closure member having an upper edge and a lower edge and first and second side edge portions, said upper edge formed integral with said base portion of said second stepped level, said lower edge formed integral with said floor member and said first and second side edge portions formed integral with said second radial surface of, respectively, said first and said second side walls,
• such that said projecting members each define a gas flow path configured to permit entry of said ambient atmosphere into said inflatable air cushion upon actuation of said inflator device and thereafter to facilitate venting of said air cushion contents through said second reciprocal fluid flow means to the atmosphere surrounding said motor vehicle;
• (c) an elongated conduit formed from a material selected from an engineering thermoplastic and a lightweight, high tensile strength metal, said conduit having a first end and a second end and being configured and adapted to permit a reciprocal flow of fluid between said inflatable air cushion and said external atmosphere, wherein said first end of said conduit is lockingly engaged within said skirt portion of said mounting plate by a structural seal formed therebetween, said seal created by magnaforming a peripheral wall portion of said skirt into an open channel extending along at least a portion of an outer surface of said first end, said conduit sized to fit within a steering column of said automobile so as to extend rearwardly through said steering column from said mounting plate such that said second end thereof extends at least to a corresponding aperture defined within a firewall of said automobile, wherein said conduit is configured and adapted to permit a reciprocal flow of fluid between said inflatable air cushion and said external atmosphere;
• (d) a pyrotechnic inflator device positioned within said mounting means, said inflator device comprising a housing formed of a diffuser member having a first open end and a second closed end, and a closure plate member sealing said open end thereof, said housing further comprising a rounded shoulder extending along at least a portion of an exterior peripheral surface thereof, said shoulder adapted to permit a locking engagement of said inflator device within said mounting means;
• (e) a retaining member for maintaining said inflatable air cushion in contact relation with said inflator device, said retaining member having a first upper groove and a second lower groove extending along at least a portion of an outer surface thereof, wherein said retaining member is adapted for installation within said mounting plate in surrounding relation to said diffuser member and configured to correspond to an external shape thereof and wherein said retaining member has a plurality of slotted apertures extending entirely therethrough from a first lower surface to a second upper surface thereof, each said slotted aperture capable of being aligned, upon installation of said retaining member within said mounting plate, with one of said radially projecting members on said lower surface of said plate adjacent said second and said third stepped levels to permit said reciprocal fluid flow between said inflatable air cushion and said external atmosphere;
• (f) an inflatable air cushion in contact relation with said diffuser member of said inflator device, said cushion configured and adapted for preventing injury to said vehicle operator due to contact with an interior portion of said vehicle upon the occurrence of a primary collision, said cushion comprising means located within a mouth portion thereof configured to facilitate a locking engagement between said cushion and a first grooved portion upon an outer surface of said retaining means upon assembly of said module,
• wherein at least a portion of said mounting plate is lockingly engaged within said second grooved portion of said retaining member such that said inflator device, said retaining member forming a structural seal therebetween and said inflatable air cushion are all maintained together in locking engagement with one another within said mounting plate without the use of any additional locking means.

A method for making an automobile airbag module adapted for a reciprocal fluid flow between an atmosphere external to said vehicle and a cavity defined by an inflatable air bag operatively associated with said module, said method comprising:

• (a) positioning a pyrotechnic inflator device within means for mounting said inflator within said module, said mounting means comprising an open pan having, in series, a first, a second and a third stepped level extending rearwardly therefrom, and first means, formed integral with a lower surface of said mounting means, for permitting a reciprocal flow of fluid between said inflatable air bag and said external atmosphere, wherein said inflator device comprises along at least a portion of an outer peripheral surface thereof, an arcuate surface extending outwardly therefrom, said arcuate surface having a relatively greater diameter than a remaining portion of said device;
• (b) securing a relatively flexible locking bead within an open mouth portion of said air bag;
• (c) stretching said locking bead over an upper portion of a retaining member and into a first upper grooved portion defined thereby to form a retainer/bag assembly, said retaining member configured for installation adjacent said inflator device upon said mounting plate, in surrounding relation thereto;
• (d) lowering the retainer/bag assembly over at least an upper diffuser portion of said inflator device;
• (e) forming a first structural seal between a peripheral wall portion of said second stepped level upon said mounting plate and a second lower grooved portion of said retaining member, said second grooved portion situated relatively rearwardly from a first grooved portion;
• (f) inserting a first end of an elongated conduit member into an aperture defined by said third stepped level of said mounting means, said conduit member configured and adapted to form second means for facilitating a reciprocal fluid flow between said inflatable air bag and a surrounding atmosphere external to said automobile;
• (g) forming a second structural seal between said first end of said conduit member and said third stepped level of said mounting means;
• (h) folding said air bag for storage within said first stepped portion of said mounting means, upon an upper diffuser portion of said inflator device;
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• (i) securing a cover member to an upper peripheral portion of said mounting means, said cover member configured to conceal said retainer/bag assembly from view and to enhance the aesthetic appearance of said module.