AIR BAG MODULE

Abstract: An air bag module includes a frame (24) of channel-shape cross section and a box-shaped cover (26) of molded plastic construction which encloses a folded air bag (27). The box-shaped cover (26) is slid between the side walls (38, 40) of the frame (24) and first and second interfitting slide locking features (48, 50, 70, 72) are provided respectively on the frame (24) and the cover (26) to interlock the cover (26) to the frame (24). A cylindrical inflator (28) is installed into the frame (24) and cover (26). A retainer strap (32) encompasses the frame (24) and the cover (26) to restrain the relative longitudinal movement therebetween so that the frame (24) and cover (26) are effectively attached together.

Description: AIR BAGt MonτiLK The invention relates to an air bag module. It is well known in motor vehicles to employ an inflatable air bag to restrain an occupant . Air bags are commonly manufactured as a module subassembly for ready installation into the vehicle. The air bag module may be mounted on the instrument panel, the seat, the door or other locations within the vehicle. Air bag modules have traditionally employed a sizable metallic housing in which the inflatable air bag and an associated inflator are housed. The present invention proposes a simplified air bag module assembly which is particularly suited for use in a seat or door. An air bag module in accordance with the present invention is characterized by the features specified in claim 1. The present invention preferably provides an air bag module including a frame of channel-shape cross section and a box shaped cover of molded plastic construction which encloses a folded air bag. The box- shaped cover is slid between the side walls of the frame and first and second interfitting slide locking features are provided respectively on the frame and the cover to interlock the cover to the frame. A cylindrical inflator is installed into the frame and cover. A retainer strap encompasses the frame and the cover to restrain the relative longitudinal movement therebetween so that the frame and cover are effectively attached together. The retainer strap also has at least one apertured end flap which overlies an end of the inflator, and a fastener is installed between the end flap aperture and the inflator to attach the inflator to the frame and the cover. In a preferred version of the invention, the side walls of the frame have longitudinal extending grooves formed on the outside to seat the strap walls of the retainer and simultaneously form a shoulder on the inside of the frame which defines the slide locking feature of the frame. In another preferred version of the invention, the retainer strap has a base end which is apertured to fit over one end of the inflator and laterally spaced strap walls which extend longitudinally from the base end to a pair of apertured end flaps which overlap one another and are apertured to receive a fastener installed to the other end of the inflator. The present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a perspective view showing a vehicle seat having an air bag module; Figure 2 is a section view taken in the direction of arrows 2-2 of Figure 1; Figure 3 is a perspective view similar to Figure 1, but showing the air bag deployed to restrain an occupant; Figure 4 is a section view taken in the direction of arrows 4-4 of Figure 3; Figure 5 is a perspective view of the air bag module; Figure 6 is an exploded perspective view of the air bag module; Figure 7 is a section view taken through a seat back showing a second embodiment of the air bag module; Figure 8 is a perspective view of the air bag module of the second embodiment of Figure 7; Figure 9 is a perspective view showing a third embodiment of the air bag module; Figure 10 is a section view taken in the direction of arrows 10-10 of Figure 9; and Figure 11 is a perspective view of the retaining strap of Figure 9. Referring to Figure 1, it is seen that a vehicle seat 10 is located in a vehicle body adjacent door 12 and includes a seat back 14 and a seat bottom 16. The seat back 14 includes a frame 18 on which a air bag module 20 is mounted. As best seen in Figures 2, 5 and 6 the air bag module 20 is comprised of a frame 24, cover housing 26, inflator 28, nut 30 and retainer strap 32. Frame 24 is an extruded channel-shape including a base wall 36 and laterally spaced apart side walls 38 and 40. Side walls 38 and 40 have longitudinal extending recessed grooves 42 and 44 which cooperate with integral flanges 45 and 46 on the base wall side 36 to define slide locking features 48 and 50. The side wall 40 carries a pair of threaded studs 50 and 52 which enable attachment of the frame 24 to the seat frame 18 as shown in Figure 2. The frame 24 is of extruded construction and can be of aluminum, plastic or other suitable strength material. The cover 26 is a molded plastic box shape including side walls 56 and 58, top end wall 60, bottom end wall 62 and a break-apart wall 64. As seen in Figure 2, the break-apart wall 64 has a molded in place indent 63. An air bag 27 is folded and stored within the cover 26. The cover 26 has integrally molded legs 66 and 68 which define plastic runners 70 and 72 which provide a slide locking feature for seating within the slide locking channels 48 and 50 of the frame 24. This slide locking engagement between the cover 26 and the frame 24 is obtained by aligning the cover 26 and frame 24 end-to- end, and then sliding the runners 70 and 72 into the channels 48 and 50. As best seen in Figure 6, the end wall 60 and legs 66 and 68 of the cover 26 cooperate to define an access opening 74. A similar access opening is provided between the lower end wall 62 and the legs 70 and 72. Inflator 28 is a suitable commercially available inflator of cylindrical shape, and has a first end 78 which carries a threaded stud 80, and a second or lower blunt end 82. As best seen in Figure 6, the retainer strap 32 is of stamped steel construction and bent into a generally rectangular shape which will fit over the frame 24. In particular, the retainer strap 32 includes a base end 86 having a round aperture 88 therein. A pair of laterally spaced strap walls 89 and 90 extend integrally from the base end 86 and terminate with integral end flaps 91 and 92 which are bent to overlie one another, as shown in Figures 5 and 6. The end flaps 91 and 92, respectively, have a bifurcated configuration which defines open end slotted apertures 94 and 96. After the cover 26 is slid into the frame 24, the retainer strap 32 is installed to lock the cover 26 and frame 24 against relative sliding movement. In referring to Figure 6, it will be understood that the strap legs 89 and 90 may be bent away from one another to permit the retainer strap 32 to be installed within the grooves 42 and 44 of the frame 24 so that the rectangular shape of the retainer strap 32 encircles or encompasses the frame 24 and cover 26. The grooves 42 and 44 serve to position and retain the retainer strap 32 at the proper location. The inflator 28 is preferably slightly longer than the frame 24 so that the second or lower end 82 of the inflator 28 becomes encaptured within the aperture 88 of the base end 86 of the retainer strap 32. The open slotted apertures 94 and 96 of the end flaps 91, 92 permit the end flaps 91 and 92 to be hooked over the threaded fastener 80 of the inflator 28. As best seen in Figure 5, the nut 30 is installed onto the threaded fastener 82 to fixedly attach the retainer strap 32 onto the frame 24, while simultaneously fixedly attaching the inflator 28 to the frame 24. It will be appreciated that the inflator 28 may be installed into the module 20 either before or after the retainer strap 32 is positioned on the frame 24. Furthermore, the slotted apertures 94, 96 in end flaps 91 and 92 need not be of the open end design shown in Figure 6 if the module 20 is to be assembled by inserting the inflator 28 into the module 20 after the retainer strap 32 has already been placed into position. In addition, it will also be appreciated that the base end 86 need not have a round aperture 88, in which case the base end 86 will engage against the lower end 82 of the inflator 28. Although the presence of the longitudinally extending grooves 42 and 44 advantageously locates the retainer strap 32, it will be understood that these grooves 42, 44 are not necessary if the retainer strap 32 hooks over both ends 78, 82 of the inflator 28. Figure 2 shows the module 20 installed in the seat back 14 and located within a foam cushion 98. The foam cushion 98 is enveloped in a seat cover 100 which is stitched together at stitches 102. Upon activation of the inflator 28, the air bag 27 inflates and will burst through the foam cushion 98 and break apart stitches 102 to obtain the deployed position of Figure 3. Although it will be understood that the drawings show the air bag module 20 of this invention mounted on a seat back 14, the module 20 can also be mounted on the seat bottom 16, on the door 12 or elsewhere in the motor vehicle. Figures 7 and 8 show a second embodiment which includes a frame 124, a cover 126, inflator 128, a bolt 130, and retainer strap 132. As best seen in Figure 7, the frame 124 is of stamped or roll formed construction and the base wall 136 thereof is deformed inwardly to provide shoulder walls 144 and 146 which define slide locking channels 148 and 150. The slide locking channels 148 and 150 slidably receive runners 166 and 168 provided on the cover 126. The cover 126 has an integrally molded end wall 164 which is decoratively grained to match a decorative trim panel 165 provided on the seat back 114. The end wall 164 seats within a rectangular recess 167 of the trim panel 165. As seen in Figure 7, the activation of the inflator 128 to inflate the air bag 127 causes the air bag 127 to break the end wall 164 of the cover 126 so that the air bag 127 deploys outwardly of the seat back 114. The inflator 128 is attached to the module by installing a threaded bolt 130 through aligned apertures 194 and 196 of the end flaps 191 and 192 of the retainer strap 132. The inflator 128 has a threaded aperture for receiving the threaded bolt 130. Figures 9, 10 and 11 show a third embodiment which includes a frame 224, a cover 226, inflator 228 and a retainer strap 232. As best seen in Figure 11, the retainer strap 232 includes a base end 286 and a pair of laterally spaced strap walls 289 and 290 which extend integrally from the base end 286 and terminate with integral end flaps 291 and 292. The end flaps 291 and 292 respectively have a bifurcated configuration which defines open end slotted apertures 294 and 296. As best seen in Figure 10, the inflator 228 includes an upper first end 278 which carries a necked-down shank 298 and an enlarged head 299. As seen in Figure 10, the shank 298 is slightly smaller in diameter than the width of the slotted apertures 294 and 296 of the retainer strap 232. The end flap 291 of the retainer strap 232 has a pair of apertures 300 and 302 which straddle the slotted aperture 294. The end flap 292 has a pair of tangs 304 and 306 struck therefrom. The air bag module is assembled by installing the inflator 228 and then positioning the retainer strap 232 around the frame 224 so that the end flaps 291, 292 insert between the upper end 278 of the inflator 228 and the head 299 thereof with the end flap 292 overlying the end flap 291. The tangs 304 and 306 of the end flap 292 become seated within the apertures 300 and 302 of the end flap 291. Figure 11 shows the locked tabs 304 and 306 bent downwardly so that the locking engagement into the apertures 300 and 302 will occur automatically. Alternatively, the tabs 304 and 306 may be normally flush with the end flap 292 and then bent downwardly into the apertures 300 and 302 via appropriate tooling after the strap walls 289 and 290 have been wrapped around the module.

Claims: CLAIMS: 1. An air bag module comprising: a frame (24) of channel shape cross section including a base wall (36) and side walls (38, 40) extending integrally from the base wall (36) ; a cover (26) of molded plastic construction for enclosing a folded air bag (27) and adapted to be slid longitudinally between the side walls (38, 40) of the frame (24) ; first and second interfitting slide locking features (48, 50, 70, 72) provided respectively in the frame (24) and the cover (26) to interlock the cover (26) to the frame (24) when the cover (26) is slid into the frame (24) ; a cylindrical inflator (28) having first and second ends (78, 82) and adapted to be installed into the frame (24) to inflate the air bag (27) ; and a retainer strap (32) encompassing the frame (24) to restrain the relative longitudinal movement of the cover (26) relative the frame (24) and being fastened to the inflator (28) . 2. The module of Claim 1 further characterized by a fastener (30) installed between the first end (78) of the inflator (28) and the retainer strap (32) , and the retainer strap (32) having overlapping end flaps 91, 92 and having a base end (86) opposite the end flaps 91, 92 and the base end (86) having an aperture (88) to receive the second end (82) of the inflator (28) . 3. The module of Claim 2 in which the inflator (28) is longer than the frame (24) so that second end (82) of the inflator (28) extends outside the confines of the frame (24) and the cover (26) to be captured within the aperture (88) of the base end (86) of the retainer strap (32) . 4. The module of claim 1 further characterized by the retainer strap (32) having a base end (86) adjacent the second end (82) of the inflator (28) , laterally spaced strap walls (89, 90) extending longitudinally along the inflator (28) to the first end (78) of the inflator (28) , and a pair of apertured end flaps (91, 92) which overlap one another. 5. The module of claim 1 further characterized by the side walls (38, 40) of the frame (24) having longitudinal extending grooves (42, 44) formed on the outside thereof to seat the strap walls (89, 90) of the retainer strap (32) to locate and retain the retainer strap (32) relative to the frame (24) . 6. The module of claim 5 in which the grooves (42, 44) formed in the side walls (38, 40) of the frame (24) concomitantly form flanges (45, 46) on the inside of the frame (24) which defines the slide locking features (48, 50) of the frame (24) . 7. The module of claim 1 in which the slide locking feature of the cover (26) is defined by a runner structure (70, 72) which is integrally molded on the cover (26) . 8. The module of claim 1 further characterized by the frame (124) being of extruded construction and having a shoulder structure (144, 146) integrally extruded therein to define the slide locking features (148, 150) of the frame (124) . 9. The module of claim 1 further characterized by the cover (26) being of molded plastic and having an integrally molded break apart wall (64) through which the inflating air bag (27) deploys. 10. The module of claim 9 further characterized by the plastic cover (126) being decoratively trimmed to close and open a decorative trim panel (165) . 11. The module of claim 2 further characterized by the inflator (28) having a threaded stud (80) and the end flaps (91, 92) being bifurcated to define open end slotted apertures (94, 96) by which the end flaps (91, 92) may be slipped about the threaded stud (80) . 12. The module of Claim 1 in which the retainer strap (232) has apertured end flaps (291, 292) separable to permit installation of the retainer strap (232) about the frame (224) and fastening means (300, 302, 304, 306) acting to concomitantly attach together the end flaps (291, 292) of the retainer strap (232) and attach the inflator (228) to the retainer strap (232) . 13. The module of claim 12 in which the fastening means includes the retainer strap (232) having apertured end flaps (291, 292) overlapping one another and having a tang (304, 306) struck from one end flap (292) to engage with an aperture (300, 302) of the other end flap (291) to attach together the end flaps (291, 292) of the retainer strap (232) , and the inflator (228) includes a headed projection (299) captured by apertured end flaps (291, 292) .

Inventors: BROOKEY MICHAEL WILLIAM, SPENCER GRAHAM THORTON, WINTERS MARK THOMAS, BROOKEY, MICHAEL, WILLIAM, SPENCER, GRAHAM, THORTON, WINTERS, MARK, THOMAS
Applicants: GEN MOTORS CORP, GENERAL MOTORS CORPORATION
Application year: 1996
Main classification: B60R21
IPC codes: B60N2, B60R21