INFLATABLE BOLSTER

FIELD OF THE INVENTION

The present invention relates generally to the field of safety devices for vehicles. More particularly, it concerns an inflatable bolster for use in the passenger compartment of a vehicle.

BACKGROUND OF THE INVENTION

Bolsters and the like are known in the art. A conventional bolster is mounted within a passenger compartment and includes a hollow body and an inflator for injecting a pressurized fluid into the hollow body. In order to reduce the potential for injuries caused during an impact event or the like, the inflator is activated upon detection of such an event and the bolster is inflated.

For example, the impact event may be a front, rear or side impact, a rollover, or any other event which is likely to cause a rapid change in the vehicle's momentum and thereby cause the occupant to strike some portion of the vehicle's passenger compartment. The fluid released by the inflator into the hollow body serves to inflate the bolster, bringing its outer surface closer to an occupant. By decreasing the distance between the occupant and its outer surface, the bolster can absorb more of the occupant's momentum over a longer period of time, thereby lessening the force experienced.

Bolsters may be provided as part of an instrument panel, a door panel, roof panel, a head rest, or other interior portion of the vehicle.

Known in the art are the following patent and patent applications which disclose inflatable bolsters and the like: US 2007/0108747; US 6,032,978; US 6,203,057; US 6,305,710; SU

6,517,103; US 6,578,867; US 6,619,689; US 6,758,493; US 6,848,715; US 6,976,706; US 7,350,852; and WO 2006/132990.

Also known are the problems which arise when mounting such bolsters to the vehicle's interior, which is typically difficult to access. Moreover, it has been found that the reaction forces generated during inflation of the bolster can be violent enough to break the bolster free from its mounting within the vehicle, thereby significantly reducing its efficacy.

As such, it would be advantageous to provide an inflatable bolster which may be more conveniently installed. It would also be advantageous to provide an inflatable bolster which is mounted to vehicle in a robust and reliable way.

In addition, it is also known that conventional bolsters are often attached to the vehicle interior by bolts which are passed from inside the hollow body in order to connect with a complementary component such as a nut or a clip. It will be appreciated that this requires accessing the inside of the hollow body and drilling holes therein. However, such opening and/or drilling of the hollow body can weaken the hollow body and/or leave debris therein. In addition, it is known that significant pull-out forces are generated at the mounting points during inflation of a bolster. Mounting points with a conventional bonding structure, such as a simple bolt, may be insufficient to retain the bolster and the expanding vessel tear loose.

It would therefore be advantageous to provide an inflatable bolster which could be attached to the vehicle interior in a more robust way, without requiring an opening or drilling of the bolster.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an inflatable bolster for use in a passenger compartment of a vehicle that satisfies at least one of the above-mentioned needs.

In accordance with an aspect of the present invention, that object is achieved with an inflatable bolster comprising a hollow body with a first wall devised to face a mating surface of the vehicle, the first wall being provided with a molded cavity, a second wall opposite the first wall and devised to face the passenger compartment, and an air chamber formed between the first and second walls. The bolster also comprises an inflator for injecting a pressurized fluid into the air chamber and thereby inflating the hollow body, the inflator being mounted to the hollow body, and an attachment mechanism for attaching the hollow body to the mating surface. The attachment mechanism includes a base retained within the molded cavity, and a fastener projection extending outward from the base and the first wall, the fastener projection devised to engage a complementary element on the mating surface and attach the inflatable bolster thereto.

Preferably, the molded cavity is formed around the base during molding of the hollow body, thereby encapsulating the base in the first wall. Alternatively, the base portion may include a male dovetail portion and the molded cavity includes a corresponding female dovetail portion having a side opening for allowing insertion of the male dovetail portion therein.

In accordance with another aspect of the present invention, the above mentioned object is achieved with an inflatable bolster comprising a hollow body with a first wall devised to face a mating surface of the vehicle, a second wall opposite the first wall and devised to face the passenger compartment, and an air chamber formed between the first and second walls. The bolster also comprises an inflator for injecting a pressurized fluid into the air chamber and thereby inflating the hollow body, the inflator being mounted to the hollow body, and an attachment means for attaching the hollow body to the mating surface, the attachment means includes a dovetail portion extending outward from the first wall, the dovetail portion devised to engage a slot on the mating surface and attach the inflatable bolster thereto.

Preferably, the mating surface includes a reaction plate for strengthening the inflatable bolster, the complementary element includes a slot, the slot having a side opening for allowing insertion of the dovetail portion therein; wherein the engagement of the dovetail portion and the slot retains the reaction plate to the inner wall.

As can be appreciated, an inflatable bolster according to either of the above-mentioned aspects may advantageously facilitate installation and/or may be attached without requiring an opening or drilling of the bolster.

Further aspects and advantages of the present invention will be better understood upon reading of preferred embodiments thereof with respect to the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a perspective view of an inflatable bolster according to a first preferred embodiment of the present invention.

Figure 1 A is a cross-sectional view taken along line A-A of Figure 1.

Figure 1 B is a close up of an attachment means in accordance with the embodiment of Figure 1.

Figure 2 is a perspective view of an inflatable bolster according to a second preferred embodiment of the present invention.

Figure 2A is a cross-sectional view taken along line B-B of Figure 2.

Figure 2B is a close up of an attachment means in accordance with the embodiment of Figure 2.

Figure 3 is a perspective view of an inflatable bolster according to a variation of the embodiment of Figure 2.

Figure 3A is a cross-sectional view taken along line C-C of Figure 3.

Figure 3B is a close up of an attachment means in accordance with the embodiment of Figure 3.

Figure 4 is a perspective view of an inflatable bolster according to third preferred embodiment of the present invention.

Figure 4A is a cross-sectional view taken along line D-D of Figure 4.

Figure 4B is a close up of an attachment means in accordance with the embodiment of Figure 4.

Figure 5 is a perspective view of an inflatable bolster according to a fourth preferred embodiment of the present invention.

Figure 5A is a cross-sectional view taken along line E-E of Figure 5.

Figure 6 is a perspective view of an inflatable bolster according to a fifth preferred embodiment of the present invention.

Figure 6A is a cross-sectional view taken along line F-F of Figure 6.

Figure 6B is a cross-sectional view taken along line G-G of Figure 6.

Figure 6C is an exploded view of the embodiment of Figure 6.

Figure 6D is a close up of an attachment means in accordance with the embodiment of Figure 6C.

Figure 7 is a perspective view of an inflatable bolster according to a sixth preferred embodiment of the present invention.

Figure 7A is a cross-sectional view taken along line H-H of Figure 7.

Figure 7B is a cross-sectional view taken along line l-l of Figure 7.

Figure 7C is an exploded view of the embodiment of Figure 7.

Figure 7D is a close up of an attachment means in accordance with the embodiment of Figure 7.

Figure 8 is a perspective view of an inflatable bolster according to a seventh preferred embodiment of the present invention.

Figure 8A is a cross-sectional view taken along line J-J of Figure 9.

Figure 8B is a close up of an attachment means in accordance with the embodiment of Figure 8.

Figure 9 is a perspective view of an inflatable bolster according to an eighth preferred embodiment of the present invention.

Figure 9A is a cross-sectional view taken along line K-K of Figure 9.

Figure 9B is an exploded view of the embodiment of Figure 9.

While the invention will be described in conjunction with example embodiments, it will be understood that it is not intended to limit the scope of the invention to such embodiments. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included as defined by the present description and appended claims.

DESCRIPTION OF PREFERRED EMBODIMENTS

In the following description, similar features in the drawings have been given similar reference numerals and in order to lighten the figures, some elements are not referred to in some figures if they were already identified in a preceding figure.

With reference to Figure 1 , an inflatable bolster 10 according to a first preferred embodiment of the invention is illustrated. For the sake of clarity, the vehicle interior into which the bolster 10 is to be installed has not been shown. It will be appreciated however that the bolster 10 could be installed, or adapted to be installed, in a variety of places within the passenger compartment of a vehicle.

The bolster 10 comprises a hollow body 12, an inflator 14 mounted thereto, and attachment means 16 for mounting the hollow body 12 to a mating surface within the vehicle. It will be appreciated that the expression mating surface should not be considered in a limiting manner, but rather should be considered to include all manner of structures, such as brackets and the like, to which the bolster 10 may be similarly mounted.

With additional reference to Figures 1A and 1 B, the attachment means 16 is illustrated in cross-section and in close-up, respectively.

The hollow body 12 is preferably molded from a suitable plastic material. More preferably, the hollow body 12 is made by extrusion blow molding, which is known in the art and will not be discussed further herein. The hollow body 12 comprises a first wall 18 and a second wall 20 which is opposite the first wall 18. An air chamber 22 is formed between the two opposite walls 18 and 20. When installed, the first wall 18 engages the vehicle's mating surface, and is therefore hidden from view, while the second faces the passenger compartment and any driver, passengers or otherwise therein.

The inflator 14, as is known in the art, is typically provided as a cartridge, although it will be appreciated that various other types of inflators are within the scope of the present

embodiment. The inflator 14 is in fluid communication with the air chamber 22 and able to inject a pressurized fluid, typically a gas, therewithin. When installed, the inflator 14 is linked to various vehicle sensors which detect impact events and the like and are operable to activate the inflator 14 accordingly.

The first wall 18 is provided with a plurality of pleats 24, sometimes referred to as ribs, which surround the inflator 14 and the attachment means 16 concentrically. As is known in the art, these pleats 24 permit the bolster 10 to expand outward from the vehicle's mating surface and into the passenger compartment when inflated.

The attachment means 16, which can also be called an insert, comprises a base 26 and a fastener projection 28 which extends outwards therefrom. The first wall 18 comprises a molded cavity 30 which is formed as the hollow body 10 is molded and serves to receive and retain the base 26. The base 26 preferably has a flat shape which, when received within the molded cavity 30 extends in a direction substantially parallel to the first wall 18.

In accordance with the embodiment illustrated in Figures 1 , 1A and 1 B, the base 26 is preferably encapsulated within the first wall 18. For example, during blow molding of the hollow body 12, a molten plastic parison is extruded from a die and inflated within a mold.

The attachment means 16 is held within the mold such that the first wall 18 envelops the base 26, as seen in Figure 1A. Once the molded hollow body 12 has cooled and hardened, the molded cavity 30 has formed around the base 26 such that it is now retained by the first wall 18.

Also in accordance with the embodiment illustrated in Figures 1 , 1 A and 1 B, the fastener projection 28 is a threaded stud which is able to engage a corresponding component, such as a nut, in order to attach the bolster 10 to the vehicle. Preferably, four such attachment means 16 are provided around the first wall 18 and within the pleats 24, although it will be appreciated that various other arrangements are similarly possible. These mounting points are operable to accommodate the bolster reaction forces that occur during inflation.

The base 26 can be injection molded around the threaded stud 28. In order to increase the strength of its encapsulation, the base 26 preferably has a disk-like shape and comprises a series of radial alternating ridges 32, as illustrated, which provide a greater surface area for contact with the material of the first wall 18 and further provide mechanical means for preventing the attachment means 16 from spinning within the molded cavity 30. In addition, the base 26 is preferably formed from a material which is compatible with the first wall 18. Specifically, it is preferable that the materials of the base 26 and the first wall 18 have similar surface energies in order to promote polymer bonding therebetween. Examples of such compatible materials include, but are in no way limited to, polyolefins with similar surface energies such as thermoplastic polyolefin (TPO), polypropylene or polyethylene-polypropylene copolymers. Preferably, the bolster 10 bonds a TPO to a TPO

With reference to Figures 2, 2A and 2B, an inflatable bolster 10 according to a second preferred embodiment of the invention is illustrated. The bolster 10 is substantially similar to the first preferred embodiment, with the exception of the attachment means 16. In this embodiment, the fastener projection 28 is a clip which is operable to be received in a corresponding component in the vehicle's mating surface. In addition, the base 26 and the fastener projection 28 are preferably injection molded as a single piece. It will be appreciated that various other types of clips may similarly be used, such as snaps and catches.

With reference to Figures 3, 3A and 3B, a variation of the attachment means 16 of the second preferred embodiment is illustrated. In particular, the circular-shaped attachment means 16a of Figures 2, 2A and 2B is provided in the lower right hand side of the first wall 18, while alternate attachment means 16b and 16c are further provided. The attachment means 16b comprises an oval base 26 and an additional projection, for example for alignment. The attachment 16c comprises an irregular-shaped base 26, for example for strengthening its retention within the molded cavity 30. In each case, the attachment means 16 is preferably encapsulated in the first wall 18

With reference to Figures 4, 4A and 4B, an inflatable bolster 10 according to a third preferred embodiment of the invention is illustrated. The bolster 10 is substantially similar to the first and second embodiments, with the exception of the attachment means 16. In this embodiment, the fastener projection 28 is a duel level snap clip. In order to achieve a snap fit installation requiring a low installation force and the ability to have a second stage elevated retention force, the attachment means 16 is provided duel level snap clip 28, which is operable to be received in a corresponding component in the vehicle's mating surface. The clip 28 is preferably integrally injection molded with the base 26.

In use, a first snap 34 allows the vehicle assembler to attach the bolster 10 to the mating surface using a low force. During deployment of the bolster, the expansion forces will generate a higher force pushing the clip 28 further into the corresponding component which causes the clip 28 to engage the second snap 36. Once engaged, the second snap 36 requires significantly higher extraction force and as a result is able to remain installed when experiencing high pull out forces during deployment.

With reference to Figures 5 and 5A, an inflatable bolster 10 according to a fourth preferred embodiment of the invention is illustrated. The bolster 10 is substantially similar to the previous preferred embodiments, and in particular the second preferred embodiment, with the exception of the first wall 18 which comprises angled sections 38 which allow the bolster 10 to be installed in an orientation that is not parallel to the molding line of draw 40. This enables the bolster 10 to be utilized in applications where the attachment means 16 parallel to the line of draw is not acceptable. For example, the bolster 10 may be snapped into a structure such as an instrument panel, a door panel or a door pillar within the vehicle. The orientation of this structure may be normal to that of the bolster's line of draw. In order to enable the snapping in of the bolster 10, a different orientation of the feature may be preferable. In order to ease assembly, the orientation of the mating surface may therefore be accommodated while considering any interference from other parts of the vehicle.

With reference to Figures 6, 6A, 6B, 6C and 6D, an inflatable bolster 10 according to a fifth preferred embodiment is illustrated. In this embodiment, the molded cavity 30 comprises a female dovetail portion 42. As seen in particular in Figure 6A, the female dovetail portion 42 comprises a pair of opposing sides which taper inwardly from the outside of the first wall 18. The base 26 of the attachment means 16 forms a corresponding male dovetail portion 44 having a pair of opposing sides which taper outwardly. The molded cavity 30 further comprises a side opening 46 for allowing the male dovetail portion 44 to be slid therein, as seen in Figure 6C. It will be appreciated that the "male" and "female" features of a dovetail construction may similarly be referred to as "positive" and "negative" features, respectively.

The molded cavity 30 and the female dovetail portion 42 are formed during molding of the hollow body 12. Preferably, the molded cavity 30 further comprises an alignment area 48 which is at least as wide as the male dovetail portion 44 and provided adjacent the side opening 46. During assembly, the vehicle assembler can place the male dovetail portion 44 within the alignment area 48 before sliding it into the female dovetail portion 42. Once inserted, the corresponding angled surfaces of the female and male dovetail portions 42 and 44 will prevent the attachment means 16 from being pulled out. In addition, molded cavity 30 preferably comprises a snap feature 50 which allows sliding of the male dovetail portion 44 into the female dovetail portion 42, but prevents it from sliding outward therefrom and back into the alignment area 48.

In this embodiment, the fastener projection 28 is similar to that of the first embodiment.

With reference to Figures 7, 7A, 7B, 7C and 7D, an inflatable bolster 10 according to a sixth preferred embodiment of the invention is illustrated. The bolster 10 is substantially similar to the fifth embodiment, with the exception of the fastener projection 28 which is provided herein as a clip.

With reference to Figures 8, 8A and 8B, an inflatable bolster 10 according to a seventh preferred embodiment of the invention is illustrated. The bolster 10 is substantially similar

to the first embodiment, with the exception of the attachment means 16. In this embodiment, the attachment means 16 is a spring bolt. The spring bolt 16 comprises a coil portion 52 attached to a hook portion 54.

In use, the spring bolt 16 is twisted through a reaction plate 56 (Figure 8A) and into the bolster 10. The reaction plate 56 comprises a contoured surface 60 which is tapers upwardly. Once inserted into the hollow body 12, the coil portion 52 engages the first wall

18. A 180° rotation of the spring bolt 16 drives the hook portion 54 along the surface contour, thereby pushing the reaction plate 56 towards the first wall 18. Preferably, the contoured surface locks the hook portion 54 in place once the spring bolt 16 has been fully rotated, preventing unintended unwinding and/or disassembly of the parts in the field.

Preferably, the spring bolt is made from a resilient material which can stretch during deployment of the bolster 10 in order to reduce the local force concentrations thereon while maintaining the bolster 10 in its desired position. It will be appreciated that the reduced internal bolster forces will increase the bolster operating window.

With reference to Figures 9, 9A and 9B, an inflatable bolster 10 according to an eighth preferred embodiment of the invention is illustrated. The bolster 10 is substantially similar to the previous preferred embodiments, with the exception of the attachment means 16. In this embodiment, the attachment means 16 comprises a dovetail portion 58 which tapers outwardly from the first wall 18.

The dovetail portion 58 is devised to engage a corresponding slot 60 on the reaction plate 56, although it will be appreciated that such a slot 60 would similarly be used in a variety of other types of mating surfaces. The slot comprises a side opening 62 for allowing the dovetail portion 58 to be slid therein. Preferably, the slot 60 comprises an alignment area 64 adjacent the side opening 62. During assembly, the alignment area 64 can be placed around the dovetail portion 58, or vice-versa, before sliding the dovetail portion into the slot 60.

The dovetail portion 58 provides strength required to hold the bolster in position under operating conditions and allows for installation without access to the rear side of the bolster 10. It will be appreciated that the dovetail portion 58 may be of various configurations known as being male or female.

Although the present invention has been explained hereinabove by way of a preferred embodiment thereof, it should be understood that the invention is not limited to this precise embodiment and that various changes and modifications may be effected therein without departing from the scope of the invention.