GB2340458A

GB2340458A - An air bag arrangement

Info

Publication number: GB2340458A
Application number: GB9918728A
Authority: GB
Inventors: Homayoun Karimi
Original assignee: MG Rover Group Ltd
Current assignee: MG Rover Group Ltd
Priority date: 1998-08-14
Filing date: 1999-08-10
Publication date: 2000-02-23
Also published as: GB9817599D0; GB9918728D0

Abstract

An air bag arrangement (1) in which a bowed air bag portion (2) is associated with a torso air bag portion (8) such that the bowed air bag portion (2) initially engages an occupant in their leg/knee area (5). This manipulates the occupant into an appropriate position so that the torso air bag portion (8) can be deployed effectively after the bowed air bag portion (2) has been deployed.

Description

2340458 - 1 AN AIR BAG ARRANGEMENT The present invention relates to an air

bag arrangement and more particularly to an air bag arranged used with regard to front occupants of a motor vehicle.

The use of air bags within motor vehicles has become relatively commonplace. Thus, the manner of operation of air bags and their function is well known to those skilled in the art. In essence, an expansive cushion is presented to a motor vehicle occupant in order to absorb their kinetic energy along with protecting the occupant from percussive contact with relatively hard surfaces within the vehicle during collision impacts.

Unfortunately, occupants of a motor vehicle may move or otherwise present themselves in orientations that diverge significantly from those expected. Thus, when an airbag is deployed, these mal-aligned or merely unusually shaped occupants can receive asymmetric deformation force exchange with the inherent possibility of such engagement with the 15 deploying airbag arrangement itself producing injury to the occupant.

It will also be understood that typically within a motor vehicle, several air bags may be deployed in order to protect the vehicle occupants torso, legs, side, etc. In such circumstances, it will be appreciated that these separate air bags can deploy at varying rates and speeds dependent upon the inflation gas generating means and the volume of the particular air bag along with shape, etc. Thus, these air bag deployments may themselves jostle the occupant from the ideal position for symmetrical or acceptable engagement with the whole air bag arrangement provided to protect the 5 occupant during vehicle collision impacts.

It is an object of the present invention to provide an air bag arrangement which substantially relieves the above-mentioned problems.

In accordance with the present invention there is provided an air bag arrangement for a motor vehicle, the arrangement including a bowed portion arranged to deploy adjacent to a vehicle occupant's legs in order to embrace those legs and so manipulate that occupant into more consistent engagement for subsequent frontal engagement with a torso portion of the arrangement emanating from the bowed portion to provide more symmetrical deployment force engagement between the occupant and air bag arrangement.

Preferably, the bowed portion comprises a head section with wing sections either side, the head section and the wing section being coupled through appropriate vent valve means such that the head section inflates first to engage the occupants legs and subsequently the wings sections pushed inwardly of the occupants legs in order to manipulate that occupant into consistent engagement.

The torso portion may comprise a rolled up air bag arranged above or below substantially the bowed portion and coupled through appropriate vent valve means in order to deploy the torso portion substantially after initial deployment of the bowed portion of the air bag arrangement.

The air bag arrangement may be stowed behind a bolster panel within 1 a motor vehicle with a relatively soft rib or patch panel extending over an aperture through which the air bag arrangement is deployed.

The air bag arrangement will include gas inflation means and these gas inflation means may be arranged at one end of the bowed portion or at both ends.

An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings, in which:

Figure 1 is a pictorial plan cross-section of an air bag arrangement in a stowed position within a motor vehicle; Figure 2 is a pictorial plan cross-section of an air bag arrangement depicted in a first stage of deployment; Figure 3 is a pictorial cross-section of an air bag depicted in Figures 1 and 2 at a second stage of deployment; Figure 4 is a pictorial plan cross-section of the air bag depicted in Figures 1 to 3 at a final stage of deployment; Figure 5 is a pictorial perspective of the air bag at a final stage of deployment; and Figre 6 is a pictorial perspective view of the air bag inside an instrument panel.

As indicated above, a principal concern with regard to air bag arrangement deployment is misalignment of the occupant. However, it is also a problem in air bags arrangements when stowed generally take up a relatively large volume of the front facia of a motor vehicle. This is particularly problematic with regard to the driver's front seat area where a steering wheel and other instrumentation must be provided in the facia.

In accordance with the present invention, an air bag arrangement for a driver of a motor vehicle is provided in the lower facia above the foot pedals. Furthermore, the inflation gas provided through gas canisters can be secured in the central console of the vehicle below the typical radio/HEVAC ducting and/or in the vehicle panels in front of the vehicle A or front door post.

Essentially, the present invention provides a bowed portion in the air bag arrangement which at least transiently has a relatively high gas 5 pressure in order to initially engage a vehicle occupant's leg/knee area. Subsequent torso engagement of that occupant by a torso portion of the air bag is at a relatively lower gas pressure. Thus, any asymmetric deployment force exchanged between the occupant and the air bag is less detrimental to that occupant in that the torso portion of the air bag at such lower pressure will be more easily distorted. Furthermore, the higher gas pressure bowed portion can urge the occupant into better symmetrical or desired alignment for protection.

Figures 1 to 4 illustrate various stages of deployment of an air bag arrangement in accordance with the present invention. Thus, in Figure I the air bag arrangement is shown in a stowed position behind a facia panel 1 of a motor vehicle. Essentially, an air bag 2 is secured to gas inflation means 3 just behind a rupturable surface 4 of the panel 1. This rupturable surface 4 can be a patch secured across an aperture in the panel 1 through which the air bag 2 is deployed.

Upon detection of a sufficiently severe impact, the gas inflation means 3 will be initiated in order to inflate the air bag 2. This inflation will force the air bag 2 through the rupturable surface 4 towards an occupant. As the rupturable surface 4 is hidden below any visual facia within a vehicle, it will be appreciated that relatively weakly rupturable materials may be used as inadvertent knock or dint damage, ete, will then not be normally viewed. In such circumstances, there will be little resistance to deployment of the air bag 2 through the rupturable surface 4.

1 It will be noted that the air bag 2 as initially deployed has a sausage or 10 bowed shape with the gas inflation means 3 secured at one end thereof However, it will also be understood that gas inflation deployment means could be secured at both ends of the air bag 2. The advantage of such location of the gas inflation means is that again the bulk of the gas inflation canisters typical of such gas inflation means can be secured in relatively -15 unintrusive areas about the vehicle front facia, ie. in the central console below the radio/HEVAC system or panelling or just in front of the so-ca-Ued A or front door post of the vehicle. Such features will allow little intrusion into the aesthetic design of the facia immediately adjacent the steering wheel.

In Figure 2 a first stage of air bag 2 arrangement deployment is illustrated. Thus, the air bag 2 begins to inflate with gas provided from the gas inflation means 3 such that the rupture surface 4 is displaced and the bowed air bag portion 2 develops towards a vehicle occupants leglknee area 5.

In accordance with the present invention a central head section 6 of the 5 bowed portion 2 substantially develops quicker than wing portions 7 either side thereof Thus, this head section 6 substantially engages first the occupant leglknee area 5. Generally, the head section 6 will initially preferentially receive inflation gas in comparison with the wing sections 7. However, it will be understood that in certain scenarios it may be beneficial to provide at least the wing sections 7 adjacent the most detrimental central console area of the motor vehicle with adequate inflation gas to protect the occupant from percussive engagement with that console. It will be noted, during even this early first stage of air bag arrangement deployment, that the air bag 2 has begun to embrace the leg/knee area 5 of the occupant.

In Figure 3 a second stage of air bag to deployment is illustrated. Thus, the head section 6 has fully engaged the leglknee area 5 and the wing sections 7 are generally increasing in inflation pressure in order to provide inward force in the direction of arrow heads A to manipulate the occupant into appropriate desired alignment. It will be appreciated that the shape of the bowed air bag 2 to a significant extent determines the degree of such inward force A manipulation, but the rate of inflation gas insertion into the bag 2 will similarly determine the speed with which the occupant leglknee area 5 is compressed into desired alignment.

In Figure 4 a fully deployed bowed air bag 2 is illustrated. In such circumstances, the wing sections 7 have appropriately embraced and manipulated the leglknee area 5 into alignment and a torso portion 8 of the air bag 2 arrangement (shown in broken lines) has emanated from the arrangement in order to engage the occupant's upper torso.

As intimated previously, generally the bowed bag 2 will be at a significantly higher inflation gas pressure in comparison with the torso portion 8. Thus, the manipulation of the occupant through bag 2 inflation can be more conveniently achieved by the high pressures in that bag. However, the lower pressure in the torso portion 8 bag will be more malleable to occupant engagement and therefore more forgiving in terms of differential deployment force exchange with the occupant. In any event, the gas pressure in the torso portion 8 will still be sufficient to protect the occupant.

Those skilled in the art will appreciate that the torso portion 8 of the air bag 2 arrangement can be provided by a multitude of means. Thus, for example, an air bag portion 8 conventionally folded on top of the bowed bag 2 and coupled to that bag 2 through appropriate vent valves may be used.

In such circumstances, the valves would only be initiated after deployment to a predetermined extend of the bowed bag 2. This is in order to precipitate the necessary sequential deployment of the air bag 2 arrangement to appropriately engage the occupant. Furthermore, such sequential deployment will ensure sufficient inflation gas pressure in the bowed bag 2 to embrace and urge the occupant to better alignment.

Alternatively, the torso portion 8 could be held in a rolled up format above the bowed bag 2 and inflated through appropriate vent valve means 1 when the bowed back 2 has been deployed to a desired or sufficient extent.

As the torso portion 8 of the air bag 2 arrangement as indicated above is only deployed after sufficient or predetermined inflation of the bowed bag 2, it will be understood that the sequential deployment between this bowed bag 2 and the torso portion 8 is not dependent upon mere time period separation but actual deployment extent. In such circumstances, the torso portion 8 will only be deployed when the bowed bag 2 has deployed into engagement with the occupant with regard to their leg/knee area 5. Thus, the air bag 2 arrangement has an auto correction or variation in occupant position in terms of distance from the facia and occupant size. Such an auto correction feature will inherently improve the appropriateness of engagement with the occupant as the air bag arrangement is deployed. Inflation gas is only being provided to the torso portion 8 when appropriate valves between the bowed bag 2 and the torso portion 8 are activated through acquisition of sufficient inflation gas pressure in the bowed bag 2.

In Figure 5, a deployed air bag arrangement in accordance with the present invention is depicted relative to a driver or occupant seat of a motor vehicle. Thus, an air bag arrangement comprising the bowed bag 2 and torso portion 8 bag is shown deployed between a steering wheel 9 and a seat 10. Although an occupant is not illustrated, it will be appreciated that the head section 6 will clearly engage the occupant through their leg/knee area 1 below the steering wheel 9 whilst the wing section 7 will embrace and urge 10 through engagement an occupant to manipulate them into a more centrally aligned location for appropriate engagement with the torso portion 8 of the air bag. The torso portion 8 of the bag emanates from the air bag arrangement upwards from the bowed bag 2 between the steering wheel 9 and the seat 10 and so any occupant located within the seat 10.

It will be appreciated that typically the seat 10 within a motor vehicle will at least be adjustable in a lateral direction indicated by arrow heads L and possibly in a vertical direction indicated by arrow heads V. Thus, the seat 10 can vary relative to the steering wheel 9 and the facia thereabout. However, in accordance with the present invention, first deployment of the bowed bag 2 will ensure first engagement with any occupant in that seat 10 through always through their leg/knee area. Thus, secondary deployment of the torso bag 8 is only precipitated when appropriate pressure within the bowed bag 2 is achieved. In such circumstances, this bowed bag 2 will thereby adjust the stage at which the torso portion 8 bag is deployed dependent upon when it engages that occupant.

Clearly, if the engagement between the bowed bag 2 and the occupant is relatively early due to a forward position of the seat 10 or a large occupant then the torso portion 8 of the air bag will deploy relatively early.

However, if the engagement between the bowed bag 2 and occupant is relatively late due to a small occupant size or the seat being at a relatively displaced position to the facia then the torso section 8 will similarly be deployed at a later stage. In any event, the inflation gas pressure within the torso section 8 will be significantly lower than the bowed bag 2 due to vent valving between these two bags 2, 8. There is also a dilutive effect of the increased volume before deployment of the torso section 8 in combination of the bowed bag 2 in comparison with the bowed bag 2 alone during initial stages of deployment of the air bag arrangement.

Finally, it will also be appreciated that in addition to manipulating the occupant position to that more appropriate for more sympathetic engagement between the air bag arrangement, that the bowed bag 2 through which relatively high pressure is presented can substantially immobilised the lower half, ie. leglknee area of the occupant in order to ensure at least transient but resilient retention of the occupant position within the vehicle interior during relatively violent collision impacts.

In Figure 6 the air bag arrangement is illustrated in front perspective.

Thus, the bowed air bag 2 is located below the facia panel 1 and above a floor pan 61 but between the 'W' post 62 and the console 63 of a motor vehicle. In such circumstances, it will be appreciated that an occupant located above the floor pan 61 with feet engaging pedals 64 will be engaged by the air bag 2 as described above. Furthermore, the bag 2 will protect 1 that occupant from injury through contact with the panel 1, vent 65, instruments 66 and windscreen 67, when deployed.

Claims

- 13CIAIMS

1. An air bag arrangement for a motor vehicle, the arrangement including a bowed portion arranged to be deployed adjacent to a vehicle occupant's legs in order to embrace those legs and so manipulate that occupant into more consistent engagement for subsequent frontal engagement with a torso portion of the arrangement emanating from the bowed portion and so provide more symmetrical deployment force exchange between the occupant and air bag arrangement.

2. An arrangement as claimed in Claim 1, wherein the bowed portion comprises a head section with wing sections either side, the head section and wing sections being coupled through appropriate vent valve means in order that during deployment that head section initially engages the occupant's legs whilst subsequently the winged sections are inflated to push inwardly those occupant legs.

3. An air bag arrangement as claimed in Claim 1 or Claim 2, wherein the torso portion comprises a folded or rolled up section of air bag arranged to deploy after a predetermined inflation volume or pressure is achieved within the bowed portion of the air bag arrangement.

4. An arrangement as claimed in Claim 1, 2 or 3, wherein the arrangement is configured for location behind a motor vehicle front facia adjacent to a steering wheel thereof

5. An air bag arrangement as claimed in any preceding claim, wherein the air bag is deployed by gas inflation means and said gas inflation means is secured to at least one end of the bowed portion of the air bag arrangement.

6. An air bag arrangement as claimed in Claim 5, wherein the gas inflation means is arranged to inflate the bowed portion from both ends simultaneously.

7. An air bag arrangement substantially as hereinbefore described with regard to the accompanying drawings.

8. A motor vehicle including an air bag arrangement as claimed in any preceding claim.