Airbag arrangement

Abstract

Airbag arrangement (80) comprising: an airbag cushion (12) configured to be stored in a roof (20) of a vehicle (22) when the airbag cushion (12) is not inflated and configured to at least partially cover an opening (24) in a side wall (28) of the vehicle (22) when the airbag cushion (12) is inflated; a first tether (14) coupled to a front edge (42) of the airbag cushion (12) at a first location adjacent to a lower edge (48) of the airbag cushion (12) and configured to be coupled to a body (38) of the vehicle (22) at a second location that is an A-pillar (36) of the vehicle (22), wherein a length of the first tether (14) between the first and second locations is configured to vary as the airbag cushion (12) is deployed; and a first roller (16) attached at the first location to the A-pillar (36) of the vehicle (22), the first tether (14) having a first end (50) attached at a third location to the lower edge (48) of the airbag cushion (12) and a second end (52) attached at the first location to the front edge (42) of the airbag cushion (12), the first tether (14) extending from the lower edge (48) of the airbag cushion (12) to the A-pillar (36), extending along the A-pillar (36) and at least partially around the first roller (16), and extending from the first roller (16) to the front edge (42) of the airbag cushion (12); wherein the first tether (14) includes a first segment (54), a second segment (56), and a third segment (58), the first segment (54) extending between the A-pillar (36) and the lower edge (48) of the airbag cushion (12), the second segment (56) extending between the first and third segments (58) along the A-pillar (36), the third segment (58) extending between the first roller (16) and the front edge (42) of the airbag cushion (12); and wherein the airbag assembly (80) further comprises a second roller (60) attached to the A-pillar (36) at a fourth location rearward of the third location, wherein the first segment (54) of the first tether (14) extends between the second roller (60) and the lower edge (48) of the airbag cushion (12) along the front edge (42) of the airbag cushion (12), and wherein the second segment (56) of the first tether (14) extends between the first and second rollers (60) along the A-pillar (36); characterized in that the airbag assembly (80) further comprises a second tether and a third roller (84), the third roller (84) being attached to the A-pillar (36) at a fifth location rearward of the fourth location, and the second tether extending from the lower edge (48) of the airbag cushion (12) to the third roller (84), extending at least partially around the third roller (84), and extending from the third roller (84) to the forward edge (42) of the airbag cushion (12).

Description

INITIATIONThe present invention relates to an airbag arrangement according to the preamble of claim 1, as is known in the art substantially from US 2002 / 0 175 502 A1.Further prior art is evident from the publications US 2004 / 0 140 653 A1 and U.S. Pat. No. 6,168,194 B1.Roof frame airbags are stored in a roof frame of a vehicle and are deployed downward to cover an inner surface of a side wall of the vehicle. Usually, the roof frame of a vehicle is formed of an A pillar of the vehicle and a C pillar of a vehicle. The portion of the side wall of a vehicle covered by a roof frame airbag typically includes a B-pillar of the vehicle, a front window opening of the vehicle, and a rear window opening of the vehicle.Roof frame airbags are typically configured to protect an occupant in a vehicle if the vehicle is involved in a side impact. In some vehicles, a roof frame airbag may be configured to reduce the likelihood that an occupant may be expelled from the vehicle. Roof frame airbags configured for exhaust reduction are sufficiently rigid without any outer reinforcement lock or reinforcement bar behind portions of the roof frame airbag (e.g., portions covering window openings) to receive an occupant impacting the airbag. Thus, roof frame airbags designed for exhaust mitigation are typically wider, higher, and stronger than roof frame airbags designed for side impacts alone.SUMMARYAccording to the invention, an airbag arrangement is presented which is distinguished by the features of claim 1.According to one example, the first tether is configured to remain taut while the length of the first tether varies between the first and second locations.According to one example, the length of the first tether decreases between the first and second locations as the airbag cushion is deployed.According to one example, the airbag cushion exerts a downward force on the first segment of the first tether when the airbag cushion is deployed, which in turn exerts a rearward force on the second segment of the first tether and a forward force on the third segment of the first tether.According to one example, the first segment of the first tether runs vertically along a B-pillar of the vehicle when the airbag cushion is inflated.According to one example, the airbag assembly further includes a plurality of guides attached to the airbag cushion along the front edge of the airbag cushion. The first segment of the first tether passes through the plurality of guides.According to one example, the airbag assembly further includes a plurality of guides attached to the airbag cushion at locations along a B-pillar of the vehicle when the airbag cushion is inflated. The second tether passes through the plurality of guides.According to one example, the airbag assembly further includes a tensioning mechanism that applies tension to the first tether and thereby removes a slack portion from the first tether while the airbag cushion is deployed.According to one example, the tensioning mechanism secures the first tether at the second location to an A-pillar of the vehicle.According to one example, the airbag assembly further includes a second tether that is attached to the front edge of the airbag cushion at a third location and that is attached to the A-pillar at a fourth location. The third and fourth locations are higher than the first and second locations, and the fourth location is behind the second location.According to one example, a length of the second tether is fixedly set between the third and fourth locations.According to one example, the tensioning mechanism includes a coil spring, a spring retainer, and a third tether. The coil spring couples the first tether to the A-pillar at the second location. The spring retainer is configured to restrict the coil spring to prevent the coil spring from unwinding. The third tether couples the second tether to the spring retainer. When the airbag cushion is deployed, the airbag cushion pulls the second tether rearward, which pulls the third tether rearward, thereby releasing the spring retainer. Releasing the spring retainer allows the coil spring to unwind and thereby exert tension on the first tether.A vehicle according to the present invention includes an A-pillar, a side wall, an airbag cushion, and a tether. The side wall is disposed below the A-pillar. The airbag cushion is configured to be stored in the A-pillar when the airbag cushion is not inflated. The airbag cushion is configured to at least partially cover an opening in the sidewall when the airbag cushion is inflated. The tether is coupled at a first location to a front edge of the airbag cushion. The tether is coupled to the A-pillar at a second location. A length of the tether between the first and second locations is configured to vary as the airbag cushion is deployed.According to one example, the length of the tether decreases between the first and second locations as the airbag cushion is deployed.According to one example, the tether is configured to remain taut as the length of the tether decreases between the first and second locations.Further areas of applicability of the present invention will become apparent from the detailed description, claims and drawings. The detailed description and specific examples are intended for purposes of illustration only.BRIEF DESCRIPTION OF THE DRAWINGSThe present invention will become more fully understood from the detailed description and the accompanying drawings, in which: FIG. 1 is a side view of a first example of an airbag assembly according to the present invention; FIG. 2 is a side view of the airbag assembly of FIG. 1 when an airbag cushion of the airbag assembly is not inflated; FIG. 3 is a side view of the airbag assembly of FIG. 1 when the airbag cushion of the airbag assembly is partially inflated; FIG. 4 is a side view of the airbag assembly of FIG. 1 when the airbag cushion of the airbag assembly is partially inflated; FIG. 5 is a side view of a second example of an airbag assembly according to the present invention, the airbag assembly including an airbag cushion shown in an uninflated state; FIG. 6 is a side view of the airbag assembly of FIG. 5 when the airbag cushion of the airbag assembly is fully inflated; FIG. 7 is a side view of a third example of an airbag assembly according to the present invention, the airbag assembly including an airbag cushion shown in an uninflated state; FIG. 8 is a side view of the airbag assembly of FIG. 7 when the airbag cushion of the airbag assembly is fully inflated; FIG. 9 is a side view of a tensioning mechanism included in the airbag assembly of FIG. 7 ; FIG. 10 is an exploded perspective view of an exemplary implementation of the clamping mechanism of FIG. 9 ; and FIG. 11 is another exploded perspective view of a portion of the exemplary implementation of the clamping mechanism of FIG. 9.In the drawings, reference numerals may be used in multiple numbers to identify similar and / or similar elements.DETAILED DESCRIPTIONIn some cases, it may be a challenge to make a roof frame airbag rigid enough without an outer reinforcement barrier or reinforcement rod behind portions of the airbag to receive an occupant impacting the airbag. This challenge is exacerbated by vehicles with large window openings, such as off-road vehicles with high belt lines. To address this challenge, a roof frame airbag assembly may include a tether extending in a longitudinal direction and securing a front edge of the roof frame airbag to the A-pillar. However, in the arrangement of the tether and thus the stiffness provided by the tether, tradeoffs may be made to avoid disrupting the deployment kinematics of the roof frame airbag.For example, it may be desirable to attach the tether to the front edge of the roof frame airbag proximate to its lower edge to provide the desired stiffness. However, the tether may interfere with deployment of the roof frame airbag if the tether is too short if the tether is attached to the front edge of the roof frame airbag near its bottom edge. In addition, the tether may not provide the desired stiffness because the tether may not be tight enough when the roof frame airbag is deployed if the length of the tether is increased to avoid disrupting the deployment kinematics of the roof frame airbag. Thus, the tether may be fixed to the front edge of the roof frame airbag at a location substantially higher than the lower edge of the airbag. Such tradeoffs may limit the amount of stiffness provided by the airbag assembly.A roof frame airbag assembly according to the present invention includes a tether that extends in the longitudinal direction and couples the front edge of the roof frame airbag to an A-pillar, wherein the length of the tether is designed to vary as the airbag is deployed. The assembly includes features that remove the slack portion from the tether as the airbag is deployed such that the tether may be attached to the lower edge of the airbag proximate to its lower edge without disturbing the deployment kinematics of the airbag. The stiffness provided by the assembly may in turn be maximized.According to one example, the tether extends from the front edge of the airbag to a first pulley attached to the A-pillar, extends along the A-pillar from the first pulley to a second pulley attached to the A-pillar, and extends downward from the second pulley to the lower edge of the airbag. One end of the tether is attached to the lower edge of the airbag and the other end of the tether is attached to the front edge of the airbag. When the airbag is deployed, the airbag pulls down again at the one end of the tether, causing the tether to pull forward at the front edge of the airbag. Thus, the deployment force of the roof frame airbag in this example is used to apply tension to the tether and thereby remove the slack portion from the tether while the airbag is deployed.According to another example, the assembly includes upper and lower tethers each coupling the front edge of the airbag to the A-pillar, and a tensioning mechanism that secures the lower tether to the A-pillar while applying tension to the lower tether. The tensioning mechanism includes a coil spring, a spring retainer, and a trip tether. The coil spring applies tension to the lower tether as the coil spring unwinds. When the spring retainer is engaged, the spring retainer prevents the coil spring from unwinding. The triggering tether couples the spring retainer to the upper tether such that the spring retainer is released when the airbag is deployed, allowing the retainer spring to unwind and thereby apply tension to the lower tether. Thus, the tension mechanism in this example is used to apply tension to the tether and thereby remove a slack portion from the tether while the airbag is deployed.Referring now to FIGS. 1-4, an airbag assembly 10 includes an airbag cushion 12, one or more inflator 13, a front tether 14, a rear tether 15, a pulley 16, and a plurality of guides 18. The airbag cushion 12 is configured to cover a majority of a front window opening 24 in a side wall 28 of the vehicle 22 and a rear window opening 26 in the side wall 28 when the airbag cushion 12 is inflated as shown in FIG. 4. In the example shown, the side wall 28 is formed by and / or a portion of a front door 30 of the vehicle 22 and a rear door 32 of the vehicle 22. In other examples, the side wall 28 is part of a body structure 34 of the vehicle 22 that includes an A-pillar 36, a B-pillar 38, and a C-pillar 40. The A-pillar 36 and the C-pillar 40 constitute the roof frame 20.The airbag cushion 12 includes a front edge 42, a rear edge 44, an upper edge 46, and a lower edge 48. The front tether 14 couples the front edge 42 of the airbag cushion 12 to the A-pillar 36 of the vehicle 22. the rear tether 15 couples the rear edge 44 of the airbag cushion 12 to the C-pillar 40 of the vehicle 22. the airbag cushion 12 includes a plurality of attachment tabs 49 disposed along its upper edge 46. Fasteners may be inserted through the attachment tabs 49 to secure the airbag cushion 12 to the A-pillar 36. The airbag cushion 12 may be formed of a fabric.The inflator 13 is operable to deploy the airbag cushion 12 from an uninflated state (FIG. 2 ) to the fully inflated state (FIGS. 1 and 4 ). Each of the gas generators 13 may include an igniter and a propellant gas. When the vehicle 22 is involved in an impact, the igniter burns the propellant gas, which generates an inert gas and thereby inflates the airbag cushion 12.The front tether 14 has a first end 50 and a second end 52 opposite the first end 50. The first end 50 of the front tether 14 is attached (e.g., stitched) to the lower edge 48 of the airbag cushion 12. The second end 52 of the front tether 14 is attached (e.g., stitched) to the front edge 42 of the airbag cushion 12. The front tether 14 extends from the lower edge 48 of the airbag cushion 12 to the A-pillar 36, extends along the A-pillar 36 and at least partially around the pulley 16, and extends from the pulley 16 to the front edge 42 of the airbag cushion 12. The front tether 14 may be a cable or a strap and / or may be formed (e.g., braided, woven) from plastic (e.g., nylon) or metal (e.g., steel).The front tether 14 includes a first segment 54, a second segment 56, and a third segment 58. When the airbag cushion 12 is inflated, the first segment 54 of the front tether 14 extends vertically from the lower edge 48 of the airbag cushion 12 along the B-pillar 38 to the A-pillar 36 (e.g., to the pulley 60). The second segment 56 of the front tether 14 extends from the first segment 54 (e.g., from the pulley 60) along the A-pillar 36 to the pulley 16.The rear tether 15 has a fixed length. The rear tether 15 may be integrally formed with the airbag cushion 12, in which case the rear tether 15 may be formed of the same material as the airbag cushion 12. Alternatively, the rear tether 15 may be formed separately from and fixed to the airbag cushion 12, in which case the rear tether 15 may be formed of a different material than the airbag cushion 12. For example, the rear tether 15 may be formed of plastic or metal.The rollers 16, 60 are fixed (e.g., fixed) to the A-pillar 36. The rollers 16, 60 may include a pulley, pulley, or guide tube. The rollers 16, 60 attach the front tether 14 to the A-pillar 36 while allowing the front tether 14 to move about the rollers 16, 60. In various implementations, the roller 60 may be omitted.The guides 18 may be hooks or loops through which the front tether 14 passes. The guides 18 maintain a desired path of the front tether 14 as the front tether 14 slides through the guides 18 during deployment of the airbag cushion 12. The guides 18 may be formed of plastic or metal.With continued reference to FIGS. 1-4, the operation of the airbag assembly 10 will now be described. When the airbag cushion 12 is not inflated as shown in FIG. 2, the front tether 14 extends along the A-pillar 36 from the B-pillar 38 to the pulley 16, partially extends around the pulley 16, and is returned via the A-pillar 36. The front tether 14 may be routed through a safety guide tube in the A-pillar 36.As shown in FIGS. 2 and 3, when the airbag cushion 12 is deployed, the airbag cushion 12 extends from the roof frame 20 in a forward direction 62 to at least partially cover the front and rear window openings 24 and 26. As a result, the airbag cushion 12 exerts a downward force on the first segment 54 of the front tether 14 in the direction 62 that pulls the first end 50 of the front tether 14 in the downward direction 62. The first segment 54 of the front tether 14, in turn, exerts a force in a rearward direction 64 on the second segment 56 of the front tether 14 that pulls the second segment 56 of the front tether 14 in the rearward direction 64. As a result, the second segment 56 exerts a force on the third segment 58 of the front tether 14 in a forward direction 66 that pulls the second end 52 of the front tether 14 in the forward direction 66.Thus, the length of the first segment 54 of the front tether 14 increases, the length of the second segment 56 of the front tether 14 remains the same, and the length of the third segment 58 of the front tether 14 decreases when the airbag cushion 12 is deployed. For example, the third segment 58 has a first length 68 when the airbag cushion 12 is not inflated as shown in FIG. 2, the third segment 58 has a second length 70 when the airbag cushion 12 is partially inflated as shown in FIG. 3, and the third segment 58 has a third length 72 when the airbag cushion 12 is fully inflated as shown in FIG. 4. The second length 70 is less than the first length 68 and the third length 72 is less than the second length 70.As shown in FIG. 4, when the airbag cushion 12 is fully inflated, the first end 50 of the front tether 14 is disposed at or near the lower end of the B-pillar 38 and the second end 52 of the front tether 14 is disposed at or near the A-pillar 36. As a result, the airbag cushion 12 covers a majority of the front window opening 24. Thus, the force of deployment of the airbag cushion 12 is transmitted to the front edge 42 of the airbag cushion 12 via the tether 14 to pull the front edge 42 in the forward direction 66 and thereby cover a majority of the front window opening 24.If a head 74 (FIG. 8 ) of an occupant in the vehicle 22 impacts the airbag cushion 12, the force of the occupant impacting the airbag cushion 12 is transmitted via the front tether 14 and applied to the front edge 42 of the airbag cushion 12 in the forward direction 66. In this manner, the front tether 14 holds the front edge 42 in place and thereby retains the occupant in the vehicle 22 even when the occupant impacts the airbag cushion 12 near the front edge 42 of the airbag cushion 12. Additionally, because the length of the third segment 58 of the front tether 14 is configured to vary, the second end 52 of the front tether 14 may be secured at a deeper location to the front edge 42 of the airbag cushion 12 without preventing deployment of the airbag cushion 12. Thus, the front tether 14 holds this corner in place and thereby holds the occupant in the vehicle 22 when the head of the occupant near its corner where the front and lower edges 42 and 48 meet impacts the airbag cushion 12. The lower attachment of the second end 52 of the front tether 14 to the front edge 42 of the airbag cushion 12 also enhances the deployment kinematics of the airbag cushion 12.Referring now to FIGS. 5 and 6, except for the front tether 14 being directed differently and the airbag assembly 80 further including a center tether 82 and a pulley 84, an airbag assembly 80 is similar to the airbag assembly 10. In addition, the guides 18 through which the first segment 54 passes are also disposed adjacent to and extend along the leading edge 42 of the airbag cushion 12.The center tether 82 has a first end 86 and a second end 88 opposite the first end 86. The first end 86 of the center tether 82 is attached (e.g., stitched) to the airbag cushion 12 at or near its bottom edge 48. The second end 88 of the center tether 82 is attached (e.g., stitched) to the airbag cushion 12 at or near the corner of the airbag cushion 12 where the front and top edges 42 and 46 meet. The center tether 82 may be a cable or strap and / or may be formed (e.g., braided, woven) from plastic (e.g., nylon) or metal (e.g., steel).The center tether 82 includes a first segment 90 and a second segment 92, the first segment 90 of the center tether 82 extends from its first end 86 to the pulley 84, and when the airbag cushion 12 is inflated, as shown in FIG. 6, the first segment 90 of the center tether 82 extends vertically along the B-pillar 38 and through the guides 18 attached to the airbag cushion 12 and disposed along the B-pillar 38. The second segment 92 of the center tether 82 extends from the pulley 84 along the A-pillar 36 to the second end 88 of the center tether 82, and the pulley 84 is fixed (e.g., attached) to the A-pillar 36 above the B-pillar 38.The rollers 84 are fixed (e.g., fixed) to the A-pillar 36. The pulley 84 may include a pulley, pulley, or guide tube. The pulley 84 may attach the center tether 82 to the A-pillar 36 while allowing the center tether 82 to move around the pulley 84.Operation of the airbag assembly 80 is similar to operation of the airbag assembly 10. As shown in FIG. 5, when the airbag cushion 12 is not inflated, the airbag cushion 12 is stored (e.g., rolled up) in the A-pillar 36 of the vehicle 22. Under this condition, the length of the first segment 54 of the front tether 14 may be limited or minimized, while the second segment 56 of the front tether 14 may have a slack portion. The slack portion of the second segment 56 of the front tether 14 ensures that the front tether 14 does not interfere with the deployment kinematics of the airbag cushion 12.As shown in FIG. 6, when the airbag cushion 12 is deployed, the airbag cushion 12 extends from the roof frame 20 in the forward direction 62 until it at least partially covers the front and rear window openings 24 and 26. As a result, the airbag cushion 12 exerts a force on the first segment 54 of the front tether 14 in the downward direction 62, causing the first end 50 of the front tether 14 to move in the downward direction 62. The first segment 54 of the front tether 14 in turn pulls the second segment 56 of the front tether 14 in the downward direction 64, and the second segment 56 of the front tether 14 pulls the third segment 58 of the front tether 14 in the forward direction 66.This movement of the front tether 14 about and / or about the rollers 16, 60 eliminates the slack in the front tether 14. In addition, the deployment force of the airbag cushion 12 is transmitted via the front tether 14 to the front edge 42 of the airbag cushion 12 and thereby pulls the front edge 42 of the airbag cushion 12 in the forward direction 66.Moreover, the front tether 14 and the middle tether 82 increase the stiffness or structural rigidity of the airbag cushion 12. In turn, if the head of an occupant in the vehicle 22 impacts the airbag cushion 12, the front tether 14 and the middle tether 82 maintain the airbag cushion 12 in the position shown in FIG. 6 during the impact. As a result, the airbag cushion 12 prevents the occupant from passing through the front window opening 24 or impacting the body structure 38.Referring now to FIGS. 7-9, an airbag assembly 100 includes the airbag cushion 12, an upper front tether 102, a lower front tether 104, and a tensioning mechanism 106. Both the upper and lower front tethers 102 and 104 couple the front edge 42 of the airbag cushion 12 to the A-pillar 36. Each of the upper and lower front tethers 102 and 104 may be a cable or strap and / or may be formed (e.g., braided, woven) from plastic (e.g., nylon) or metal (e.g., steel).The lower front tether 104 has a first end 107 and a second end 108 opposite the first end 107. The first end 107 of the lower front tether 104 is secured at a first location to the front edge 42 of the airbag cushion 12 and the second end 108 of the lower front tether 104 is secured at a second location to the A-pillar 36. Due to the tension exerted by the tensioning mechanism 106 on the lower front tether 104, the length of the lower front tether 104 between the first and second ends 106 and 108 (or between the first and second locations) decreases as the airbag cushion 12 is deployed.The upper front tether 102 has a first end 110 and a second end 112 opposite the first end 110. The first end 110 of the upper front tether 102 is secured at a third location to the front edge 42 of the airbag cushion 12 and the second end 112 of the upper front tether 102 is secured at a fourth location to the A-pillar 36. The third and fourth locations are higher than the first and second locations, respectively, and the fourth location is behind the second location. As the airbag cushion 12 is deployed, the length of the upper front tether 102 remains constant between the first and second ends 110 and 112 (or between the third and fourth locations).The tensioning mechanism 106 secures the lower front tether 104 to the A-pillar 36 at the second location. In addition, the tensioning mechanism 106 applies tension to the lower front tether 104 and thereby removes the slack from the lower front tether 104 while the airbag cushion 12 is deployed. Further, by removing (e.g., rolling up) the slack in the lower front tether 104, the tensioning mechanism 106 reduces the length of the lower front tether 104 between the first and second locations while the airbag cushion 12 is deployed.As best seen in Figure 9, the tensioning mechanism 106 includes a coil spring 114, a spring retainer 116, and a release tether 118. The coil spring 114 couples the second end 108 of the lower front tether 104 to the A-pillar 36 at the second location. In addition, the coil spring 114 applies tension to the lower front tether 104 and removes a slack from the lower front tether 104 as the coil spring 114 unwinds. The coil spring 114 may be indirectly attached to the lower front tether 104 and the A-pillar 36 by other components that cause the coil spring 114 to tension the lower front tether 104 as the coil spring 114 unwinds. The spring retainer 116 restrains the coil spring 114 to prevent the coil spring 114 from unwinding when the spring retainer 116 is engaged. The spring retainer 116 allows the coil spring 114 to unwind when the spring retainer 116 is released.The trip tether 118 couples the upper front tether 102 to the spring retainer 116. The trip tether 118 has a first end 120 and a second end 122 opposite the first end 120. The first end 120 of the trip tether 118 is attached (e.g., bound, fastened, adhered) to the upper front tether 102 at a location between the first and second ends 110 and 112 of the upper front tether 102. The trigger tether 118 may be a cable or strap and / or may be formed (e.g., braided, woven) from plastic (e.g., nylon) or metal (e.g., steel).With continued reference to FIGS. 7-9, the operation of the airbag assembly 100 will now be described. When the airbag cushion 12 is not inflated as shown in FIG. 7, both the upper and lower front tethers 102 and 104 extend along the A-pillar 36 and are disposed in the roof frame 120. Also, the spring retainer 116 restrains the coil spring 114 to prevent the coil spring 114 from unwinding. When the airbag cushion 12 is deployed as shown in FIG. 8, the airbag cushion 12 pulls the upper front tether 102 rearward, which pulls the release tether 118 rearward, thereby releasing the spring retainer 116. The coil spring 114 in turn wraps and thereby applies tension to the lower front tether 104.Referring now to FIGS. 10 and 11, an example implementation of the tensioning mechanism 106 includes a spindle 124, the coil spring 114, an inner housing 126, the spring retainer 116, the trip tether 118, a coil spring 128, and an outer housing 130. The spindle 124 includes a cylindrical body 132 defining a first annular groove 134, a second annular groove 136, a third annular groove 138, and an annular slot 140. The annular slot 140 extends completely through the cylindrical body 132 of the spindle 124. The spindle 124 may be formed (e.g., molded, cast, forged, and / or machined) from plastic and / or metal.The example implementation of the coil spring 114 shown in FIG. 10 includes a spring body 142, a first tongue 144 disposed at one end of the spring body 142, and a second tongue 146 disposed at the other end of the spring body 142. The spring body 142 is a flat cable or tape wound in a spiral shape. The coil spring 114 may be formed (e.g., molded, cast, forged, and / or machined) from rubber, plastic, and / or metal. The first and second tabs 144 and 146 may be integrally formed with the spring body 142. Alternatively, the first and second tabs 144 and 146 may be formed separately from and attached (e.g., fastened) to the spring body 142.The inner housing 126 includes an annular body 148, an annular flange 150 disposed at one end of the annular body 148, a disc 152 disposed at the other end of the annular body 148, and a plurality of teeth 154 (FIG. 11 ) protruding from a rear surface 155 of the disc 152. The annular body 148 defines an elongated slot 156 that extends completely through the annular body 148. The lower front tether 104 is secured to the annular body 148 of the inner housing 126 using a fastener 158 (e.g., a rivet or a screw). The disc 152 defines a hole 160 that passes through the center of the disc 152.The spring retainer 116 includes a flat elongated body 162 and a pawl 164 projecting from one end of the elongated body 162. The pawl 164 is configured to engage the teeth 154 on the rear surface 155 of the inner housing 126. For example, the shape of the pawl 164 may complement or conform to the shape of the teeth 154. The spring retainer 116 and the inner housing 126, or the pawl 164 on the spring retainer 116 and the teeth 154 on the rear surface 155 of the outer housing 130 may collectively be referred to as a ratchet mechanism. The elongated body 162 of the spring retainer 166 defines a circular hole 165 and an elongated slot 166 extending through the elongated body 162. The hole 165 is located adjacent the end of the elongate body 162 from which the pawl 164 projects, and the elongate slot 166 is located adjacent the other end of the elongate body 162.The spring retainer 116 is pivotally mounted to the outer housing 130 using a fastener 167 (e.g., a rivet or a screw) inserted through the hole 165 into the elongated body 162 of the spring retainer 116. The second end 122 of the trip tether 118 passes through the elongated slot 166 in the spring retainer 116 to form a loop and is connected to another portion of the trip tether 118 using stitches 168. The second end 122 of the trip tether 118 is in turn attached to the spring retainer 116.The coil spring 128 urges the pawl 164 of the spring retainer 116 into engagement with one of the teeth 154 on the rear surface 155 of the inner housing 126. The coil spring 128 includes a helical body 170, a first hook 172 protruding from one end of the helical body 170, and a second hook 174 protruding from the other end of the helical body 170. The first hook 172 secures the coil spring 128 to the spring retainer 116. The second hook 174 secures the coil spring 128 to the outer housing 130.The outer housing 130 includes an annular body 176 and a disc 178. The annular body 176 defines an elongated slot 180 that extends through the annular body 176. When the tensioning mechanism 106 is assembled, the lower front tether 104 extends through the elongated slot 180 into the outer housing 130. The disc 152 defines a first circular hole 182 that passes through the center of the disc 152 and a second circular hole 184 that is offset from the center of the disc 152. The fastener 167 is inserted through the second circular hole 184 to secure the spring retainer 116 to the outer housing 130. The spring retainer 116, the inner housing 126, and the outer housing 130 may be formed (e.g., molded, cast, forged, and / or machined) from plastic and / or metal.To assemble the tensioning mechanism 106, the first tongue 144 of the coil spring 114 is inserted through the elongated slot 140 of the spindle 124, and the second tongue 146 of the coil spring 114 is inserted through the elongated slot 156 into the inner housing 126. Then, the inner housing 126 is rotatably mounted to the spindle 124 by inserting a portion of the disc 152 surrounding the hole 160 in the second annular groove 136 in the spindle 124. The inner housing 126 may be secured to the second annular groove 136 in the spindle 124 via a clearance fit that allows the inner housing 126 to rotate relative to the spindle 124. When the inner housing 126 is fixed to the spindle 124, the coil spring 114 is disposed in the inner housing 126.The spring retainer 116 is secured to the outer housing 130 by inserting the fastener 167 through the hole 165 in the spring retainer 116 and through the hole 184 in the outer housing 130. The outer housing 130 may include internal threads (not shown) disposed in the hole 184 that engage external threads on the fastener 167. When the spring retainer 116 is attached to the outer housing 130, the coil spring 28 may be disposed between the spring retainer 116 and the outer housing 130. Alternatively, the coil spring 128 may be disposed around the shank of the fastener 167 and disposed between the head of the fastener 167 and the spring retainer 160. The trip tether 118 may be routed through the elongated slot 180 in the outer housing 130 and attached to the spring retainer 116 before the spring retainer 116 is attached to the outer housing 130.The outer housing 130 with the spring retainer 116 attached thereto is assembled over the inner housing 126 and mounted to the spindle 124 by inserting a portion of the disc 178 surrounding the hole 182 in the third annular groove 138 in the spindle 124. The outer housing 130 may be attached to the third annular groove 138 in the spindle 124 via a snap fit that prevents the outer housing 130 from rotating relative to the spindle 124. As the outer housing 130 is assembled over the inner housing 126, tension may be applied to the trip tether 118 to counteract the biasing force of the coil spring 128, such that the pawl 164 does not interfere with the teeth 154 on the rear surface 155 of the outer housing 130. Before the outer housing 130 is assembled over the inner housing 126 and assembled to the spindle 124, the lower front tether 104 may be routed through the elongated slot 180 in the outer housing 130 and secured to the inner housing 126.After the outer housing 130 is assembled over the inner housing 126 and mounted to the spindle 124, the tension applied to the trip tether 118 may be released such that the pawl 164 engages one of the teeth 154 on the rear surface 155 of the outer housing 130. The clamping mechanism 106 is then fully assembled. The clamping mechanism 106 may be secured to the A-pillar 36 by inserting the spindle 124 into a hole (not shown) in the A-pillar 36 such that a portion of the A-pillar 36 surrounding the hole is disposed in the first annular groove 134 on the spindle 124. The A-pillar 36 may be attached to the first annular groove 134 in the spindle 124 via a snap fit that prevents the spindle 124 from rotating relative to the A-pillar.Turning now to FIGS. 7-12, operation of an example implementation of the tensioning mechanism 106 shown in FIGS. 10 and 11 will be described. As shown in FIG. 8, when the airbag cushion 12 is deployed, the airbag cushion 12 applies tension to the upper front tether 106, which applies tension to the deployment tether 118. The trip tether 118 in turn rotates the spring retainer 116 about the fastener 167, thereby disengaging the pawl 164 on the spring retainer 116 from the teeth 154 on the rear surface 155 of the inner housing 126. As a result, the coil spring 114 is allowed to unwind, causing the inner housing 126 to rotate relative to the outer housing 130 in a direction that the front tether 104 catches up or wraps around the inner housing 126. As a result, the coil spring 114 applies tension to the lower front tether 104 and removes (or catches up with) the slack in the lower front tether 104.

Claims

An airbag assembly (80) comprising: an airbag cushion (12) configured to be stored in a roof (20) of a vehicle (22) when the airbag cushion (12) is not inflated and configured to at least partially cover an opening (24) in a sidewall (28) of the vehicle (22) when the airbag cushion (12) is inflated; a first tether (14) coupled to a front edge (42) of the airbag cushion (12) at a first location adjacent a lower edge (48) of the airbag cushion (12) and configured to be coupled to a body (38) of the vehicle (22) at a second location that is an A-pillar (36) of the vehicle (22), wherein a length of the first tether (14) between the first and second locations is configured to vary as the airbag cushion (12) is deployed; and a first pulley (16) secured to the A-pillar (36) of the vehicle (22) at the first location, wherein the first tether (14) has a first end (50) secured to the lower edge (48) of the airbag cushion (12) at a third location and a second end (52) secured to the front edge (42) of the airbag cushion (12) at the first location, and wherein the first tether (14) extends from the lower edge (48) of the airbag cushion (12) to the A-pillar (36), extends along the A-pillar (36) and at least partially around the first pulley (16) and extends from the first pulley (16) to the front edge (42) of the airbag cushion (12); wherein the first tether (14) includes a first segment (54), a second segment (56), and a third segment (58), the first segment (54) extending between the A-pillar (36) and the bottom edge (48) of the airbag cushion (12), the second segment (56) extending between the first and third segments (58) along the A-pillar (36), the third segment (58) extending between the first pulley (16) and the front edge (42) of the airbag cushion (12); and wherein the airbag assembly (80) further comprises a second pulley (60) attached to the A-pillar (36) at a fourth location that is rearward of the third location, wherein the first segment (54) of the first tether (14) extends between the second pulley (60) and the bottom edge (48) of the airbag cushion (12) along the front edge (42) of the airbag cushion (12), and wherein the second segment (56) of the first tether (14) extends between the first and second pulleys (60) along the A-pillar (36); The airbag assembly (80) further comprising a second tether and a third pulley (84), wherein the third pulley (84) is secured to the A-pillar (36) at a fifth location that is rearward of the fourth location, and wherein the second tether extends from the bottom edge (48) of the airbag cushion (12) to the third pulley (84), extends at least partially around the third pulley (84), and extends from the third pulley (84) to the front edge (42) of the airbag cushion (12).The airbag assembly (80) of claim 1, wherein the first tether (14) is configured to remain taut while the length of the first tether (14) varies between the first and second locations.The airbag assembly (80) of claim 1, wherein the length of the first tether (14) decreases between the first and second locations as the airbag cushion (12) is deployed.The airbag assembly (80) of claim 1, wherein the airbag cushion (12) exerts a downward force on the first segment (54) of the first tether (14) when the airbag cushion (12) is deployed, which in turn exerts a rearward force on the second segment (56) of the first tether (14) and a forward force on the third segment (58) of the first tether (14).The airbag assembly (80) of claim 1, further comprising a tensioning mechanism (106) that applies tension to the first tether (14) thereby removing a slack portion from the first tether (14) as the airbag cushion (12) is deployed.

Images