Airbag cushion assembly with horn switch pocket

Abstract: A vehicle safety airbag cushion assembly (50) including an airbag cushion (52) with an open mouth (59) surrounded by a collar (58) and a strap (54) for holding the cushion (52) in a folded state prior to deployment. A first end (67) of the strap has a strap collar (62) which is connected to the airbag collar (58) and a second end (68) with tabs (72) which break away from the remainder of the strap upon deployment of the cushion. An open rectangular pocket (56) sewn to the strap (54) accommodates a horn switch (93) immediately below a horn activation face (97) of a cover (88) of an associated airbag module (85). The pocket may alternatively be sewn directly to the cushion. Bolts (91) and nuts (92) clamp the cushion collar (58) and the strap, if included, between an annular retainer (89) and a housing (87) of the module.

Description: The present invention relates to a driver side airbag module horn switch attachment and, more particularly, to an airbag cushion assembly having a horn switch pocket for receiving a horn switch assembly. Driver side airbag modules, which include an airbag cushion and an airbag module cover, are normally positioned within a hub of a steering wheel of a motor vehicle. An annular retainer ring secures the airbag cushion to the airbag module, and a cushion strap holds the airbag cushion in a folded position prior to deployment. Both the airbag module cover and cushion strap include a tear seam or weakened portion for allowing the airbag cushion to break through and fully deploy during a collision or rapid deceleration of the motor vehicle. The hub of the steering wheel happens to be the same area which conventionally includes the horn switch. Accordingly, the airbag module cover must additionally serve to actuate the horn switch. A horn switch assembly normally includes suitable components such as a membrane type horn switch and a backing plate for example, and the horn switch assembly is attached to an inner surface of a horn actuation face of the airbag module cover by ultrasonic welding or heat staking. Mounting the horn switch assembly to the airbag module cover by ultrasonic welding or heat staking is a time consuming assembly process that increases the cost of manufacturing the airbag module. In addition, the horn switches are sometimes damaged by heat staking, requiring the replacement of both the horn switch assembly and airbag module cover since the entire airbag module cover must be replaced when replacing a damaged or defective horn switch assembly welded to the airbag module cover. Furthermore, heat staking puts constraints on the design, material and manufacture of the airbag module cover. An alternative manner in which a horn switch can be incorporated into an airbag module is described in Patent US 5,265,905, on which the preamble of claim 1 is based. The module includes a backing plate to which an inflator is attached together with an airbag. An inner plastic cover of tetrapolyethylene is riveted to peripheral portions of the backing plate, covers the inflator and airbag and has a membrane type horn switch connected to its outer surface by means of inwardly facing holding tabs. A separate outer cover accommodates all elements of the module and is screwed to the backing plate. Since it will be necessary to contain the airbag in some way prior to installation of the inner plastic cover, three separate parts of the module, namely the containing means and the inner and outer covers, each need to be installed as a separate fabrication step which leads undesirably to complication of the airbag module fabrication process. An object, therefore, of the present invention is to provide an airbag module having a horn switch assembly mounted to avoid one or all of the above problems associated with prior art airbag modules and welding or heat staking a horn switch assembly to an airbag module cover. In carrying out this invention there is provided an airbag cushion assembly for use in an airbag module, the assembly comprising: an airbag cushion having a collar defining an open mouth for receiving inflation fluid; and a horn switch pocket sized to contain a horn switch assembly, the horn switch pocket having a pocket opening sized to receive a horn switch assembly, characterised in that the horn switch pocket is secured directly to the airbag cushion. A horn switch pocket according to the present invention allows a horn switch assembly to be mounted within an airbag module without being heat staked or welded to an airbag module cover. The invention together with further objects, features, advantages and aspects thereof, will be more clearly understood from the following description taken in connection with the accompanying drawings in which: FIG. 1 is a perspective view of an airbag cushion assembly according to the present invention, including an airbag cushion and horn switch pocket; FIG. 2 is a top elevational enlarged view of the airbag cushion assembly of FIG. 1 with the airbag cushion folded and the horn switch pocket located on top of the folded airbag cushion and containing a horn switch; FIG. 3 is a side elevational further enlarged view, partially in section, of the airbag cushion assembly of FIG. 2 mounted within an airbag module; The same reference numerals refer to the same elements throughout the various figures. Referring first to FIGS. 1 through 3, the present invention is directed to an airbag cushion assembly 10 including an airbag cushion 12 having a horn switch pocket 14. The airbag cushion 12 has a collar 16 forming an open mouth 18 and having a plurality of fastener receiving holes 20. An airbag cushion and the material comprising an airbag cushion are known to those skilled in the art. The horn switch pocket 14 , which can be made from the same material as the airbag cushion 12 , is generally rectangular and has a marginal edge comprising two longer opposed edges 22,23 and two shorter opposed edges 24,25 . As shown, the two longer opposed edges 22,23 and one shorter opposed edge 24 are secured to the airbag cushion 12 by stitching 26, and the other shorter opposed edge 25 forms a pocket opening 28 sized to receive a horn switch assembly. The horn switch pocket 14 is sized to contain a horn switch assembly 42, and is positioned on the side of the airbag cushion 12 towards the collar 16, as opposed to being located on the top of the airbag cushion opposite the collar, so that the horn switch pocket is less likely to come in contact with an occupant upon deployment of the airbag cushion. Referring to FIG. 3, the airbag cushion assembly 10, with the airbag cushion 12 folded, is mounted in an airbag module 30 also including an inflator 32, a module housing 34 and an airbag module cover 36. The airbag module 30 is a driver side type of airbag module for mounting in a hub of a steering wheel. The airbag module 30 is known to those skilled in the art and therefore only described in detail as is relevant to the present invention. The collar 16 of the airbag cushion 12 is sandwiched between an annular retainer ring 38 and the module housing 34, and secured with four fasteners comprising bolts 40 extending from the retainer ring. The four bolts 40, which can be unitary with the retainer ring 38, pass through the four fastener receiving holes 20 of the collar 16 of the airbag cushion 12 and are secured with nuts 41 to secure the collar of the airbag cushion to the module housing 34. As shown in FIG. 1, the collar 16 of the airbag cushion 12 is normally mounted or secured to the retainer ring 38 and bolts 40 to form a sub-assembly for shipping and handling prior to being mounted in the airbag module. The horn switch pocket 14 is shown containing the horn switch assembly 42 having suitable components such as a horn switch 43, a backing plate 44 and a lead 45 connectable to a remote horn control circuit (not shown) for example. The airbag module cover 36 includes a horn activation face 47 having an outer surface 47a and an inner surface 47b. It is intended that a driver will apply pressure to the outer surface 47a of the horn activation face 47 of the airbag module cover 36 to activate the horn switch 43 of the horn switch assembly 42. The airbag cushion 12 is folded so that the horn switch pocket 14 and horn switch assembly 42 are located between the folded airbag cushion and the inner surface 47b of the horn activation face 47 of the airbag module cover 36. For purposes of illustration, the airbag cushion 12 is shown loosely folded and packed within the airbag module cover 36. Actually, the airbag cushion 12 and horn switch assembly 42 are packed tightly against the inner surface 47b of the horn activation face 47 of the airbag module cover 36 so that the horn activation face does not have to be depressed very far to actuate the horn switch 43. Also for purposes of illustration, the airbag cushion 12 is shown thicker than it will actually be. The horn activation face 47 of the airbag module cover 36 has a tear seam 48 and hinge 49 to allow the airbag cushion 12 to break through the airbag module cover upon deployment. The horn switch pocket 14 should be positioned on the airbag cushion 12 so that upon deployment of the airbag cushion the pocket opening 28 is generally facing downwardly towards the collar 16 of the airbag cushion to reduce the chance of the horn switch assembly 42 being thrown out of the horn switch pocket. As shown, the horn switch pocket 14 is preferably positioned so that the pocket opening 28 extends below the tear seam 48 to ensure that the pocket opening will stay within the airbag module cover 36 upon deployment of the airbag cushion 12 so that the horn switch assembly 42 will not fall out. A horn switch pocket according to the present invention allows a horn switch assembly to be mounted within an airbag module without being heat staked or welded to an airbag module cover. The horn switch assembly is simply inserted into the horn switch pocket during assembly of the airbag module, and removed from the horn switch pocket during servicing or replacement of the horn switch assembly. The present invention may include other changes and modifications without departing from its true scope as defined in the appended claims. For example, the horn switch pocket could be shaped differently than shown and described to accommodate a different horn switch assembly. Also the horn switch pocket could be secured to the airbag cushion by means other than stitching such as a suitable adhesive, for example. Many changes are possible.

Claims: An airbag cushion assembly (10) for use in an airbag module (30), the assembly comprising: an airbag cushion (12) having a collar (16) defining an open mouth (18) for receiving inflation fluid; and a horn switch pocket (14) sized to contain a horn switch assembly (42), the horn switch pocket having a pocket opening (28) sized to receive a horn switch assembly, characterised in that the horn switch pocket is secured directly to the airbag cushion. The airbag cushion assembly (10) of claim 1 further comprising a retainer ring (38) secured to the collar (16) of the airbag cushion (12). The airbag cushion assembly (10) of claim 1 or 2, the horn switch pocket (14) having a marginal edge, at least a portion of which is secured directly to the airbag cushion (12). The airbag cushion assembly (10) of any preceding claim further comprising a horn switch assembly (42) contained within the horn switch pocket (14). The airbag cushion assembly (10) of any preceding claim, the horn switch pocket (14) being generally rectangular with a marginal edge divided into two longer opposed edges (22, 23) and two shorter opposed edges (24,25), the two longer opposed edges and one shorter opposed edge (24) comprising a portion of the marginal edge secured to the airbag cushion (12), and the other shorter opposed edge (25) forming the pocket opening (28). The airbag cushion assembly (10) of any preceding claim wherein a portion of a marginal edge of the horn switch pocket (14) is secured by stitching (26).

Inventors: BOYD KRISTEN KAY STITES, RICKS MERLE KAY, BOYD, KRISTEN KAY STITES, RICKS, MERLE KAY
Applicants: AUTOLIV ASP INC, AUTOLIV ASP, INC.
Application year: 1997
Main classification: B60R21
IPC codes: B60R21, H01H13, B60R16, B60Q5