WO2008048148A1

WO2008048148A1 - A safety arrangement

Info

Publication number: WO2008048148A1
Application number: PCT/SE2006/001168
Authority: WO
Inventors: Klaus-Peter KÜHNE; Karl-Heinz Sommer; Thomas Reiter; Marcus Weber; Marc Schock; Albert Jörg
Original assignee: Autoliv Development Ab
Priority date: 2006-10-17
Filing date: 2006-10-17
Publication date: 2008-04-24
Also published as: DE112006004067B4; DE112006004067T5

Abstract

A safety arrangement for a motor vehicle is disclosed. A safety arrangement comprises an air-bag module (1) which has an inflated air-bag (7) provided in fluid communication with an inflator (6), the inflator being configured to inflate the air-bag. The air-bag has an upper region (18) which is arranged so as to lie substantially adjacent the windscreen (5) of the vehicle upon inflation. The air- bag also includes a lower region (21) which is provided in fluid communication with the upper region (18). A safety arrangement comprises an inflation- restraint arrangement which is configured to restrain the lower region (21), thereby substantially preventing inflation of the lower region (21) until such time as the upper region (18) becomes inflated to a predetermined volume

Description

Title : A Safety Arrangement

Description of Invention

The present invention relates to a safety arrangement and more particularly relates to a safety arrangement for a motor vehicle in order to provide protection for a passenger in the vehicle.

It has been proposed previously to provide an air-bag located in front of a passenger in a motor vehicle, the air-bag being arranged to be inflated in the event of an impact involving the vehicle in order to provide protection for the occupant. Such air-bag arrangements are very widely known.

It is also known that whilst an air-bag might provide good protection for an occupant who, at the instant of impact, is sitting in an "ordinary" position, it has been found that the air-bag may actually injure a seat occupant, who, at the moment of impact, is not in the "ordinary" position, but instead might be leaning forwards, for example, to gain access to a glove box mounted in the dashboard of a motor vehicle.

It has therefore been proposed previously that an arrangement should be provided to detect when a vehicle occupant is out of the ordinary position and to moderate inflation of the air-bag, or even inhibit inflation of the air-bag, in such a situation, in order to reduce the risk of the air-bag itself injuring the occupant. Various such proposals have been proposed previously which involved the use of detectors to detect when a vehicle occupant is out of position, the detectors being in some way operatively connected to the air-bag in order that the inflation of the air-bag can be controlled in dependence upon Z

signals received from the detectors. Such arrangements can therefore be considered to represent "active" systems in the sense that they actively monitor the position of a vehicle occupant.

In some instances, however, it is considered desirable to provide a safety arrangement in which an air-bag is configured to inflate in such a manner as to avoid significant injury to an "out-of-position" occupant without the need for complicated and expensive detector or sensor arrangements. For example, it has been proposed that an air- bag arrangement should be provided in which an upper region of the air-bag is inflated first so as to lie substantially adjacent the windscreen of the motor vehicle, and such that a lower region of the air- bag, intended to provide protection to the abdominal region of the seat occupant, is then inflated once the upper region is sufficiently inflated. A prior proposal of this sort of arrangement is disclosed in prior publication WO2006/048147. However, this arrangement is relatively complicated in construction and may therefore not be appropriate for all motor vehicle installations.

The present invention seeks to provide an improved safety arrangement for a motor vehicle.

Accordingly, the present invention provides a safety arrangement for a motor vehicle, the safety arrangement comprising: an airbag module having an inflatable airbag in fluid communication with an inflator configured to inflate the airbag, the airbag having an upper region arranged to lie substantially adjacent the windscreen of the vehicle on inflation, and a lower region in fluid communication with the upper region, wherein the safety arrangement further comprises an inflation-restraint arrangement configured to restrain the lower region, so as to substantially prevent inflation of said lower region until said upper region is inflated to a predetermined volume. Preferably, said lower region of the airbag is arranged to provide protection to the thorax or abdomen of a vehicle occupant when inflated.

Advantageously, said inflation-restraint arrangement comprises at least one fold formed in the lower region of the airbag, and means configured to resist unfolding of the or each fold until said upper region is inflated to said predetermined volume.

Conveniently, said inflation-restraint arrangement comprises a restraint-pocket in which the lower region of the airbag is initially folded.

Preferably, said pocket defines a restricted opening for the withdrawal of said lower region therethrough.

Advantageously, said pocket is defined between part of a housing of the airbag module and a guide, the guide being located between said part of the housing and the inflator.

Conveniently, the guide is flexible.

Preferably, the guide is made of plastics material.

Advantageously, the guide is metal.

Conveniently, at least part of the guide is corrugated.

Preferably, the pocket takes the form of a pouch located inside the airbag, and wherein the lower region is initially folded inwardly of the airbag, into the pouch. Advantageously, the pouch is configured to rupture upon inflation of the upper region to said predetermined volume, in order to release the lower region of the airbag for inflation.

Conveniently, the pouch is configured to remain substantially intact during inflation of the airbag, such that the lower region is pulled out from the pouch, through said restricted opening to become released.

Preferably, said inflation-restraint arrangement comprises a re-entrant fold formed in the lower region of the airbag, and means to initially secure the fold so as to prevent unfolding of the lower region until the upper region becomes inflated to said predetermined volume.

Advantageously, said means comprises a plurality of tear-stitches configured to rupture as the upper region reaches said predetermined volume, thereby permitting the re-entrant fold to unfold.

Conveniently, said means comprises adhesive configured to release the fold as the upper region reaches said predetermined volume, thereby permitting the re-entrant fold to unfold.

So that the invention may be more readily understood, and so that further features thereof may be appreciated, embodiments of the invention may now be described, by way of example, with reference to the accompanying drawings, in which :

FIGURE 1 is a schematic cross-section of an illustration showing a safety arrangement in accordance with the first embodiment of the present invention prior to deployment; 2

FIGURE 2 illustrates two possible configurations for a component part of the safety arrangement illustrated in Figure 1 ;

FIGURE 3 is a view corresponding generally to that of Figure 1 showing the safety arrangement during an initial stage of deployment, in which the air-bag is partially inflated;

FIGURE 4 is a view corresponding generally to Figure 3 showing a subsequent stage of deployment of the air-bag in which a lower region of the air-bag has become partially inflated;

FIGURE 5 is a view corresponding generally to that of Figure 4 but illustrating a further stage in the deployment of the air-bag;

FIGURE 6 is a view corresponding generally to that of Figure 5 illustrating the air-bag in a substantially fully-inflated condition;

FIGURE 7 is a cross-sectional view illustrating an alternative configuration of a component part of the arrangement illustrated in Figures 1 to 6;

FIGURE 8 is a schematic cross-sectional illustration showing a safety arrangement in accordance with a second embodiment of the present invention during an initial stage of deployment, in which the air-bag is partially inflated;

FIGURE 9 is a view corresponding generally to that of Figure 8 illustrating a subsequent stage of deployment in which a lower region of the air-bag has become partially inflated;

FIGURE 10 illustrates a further stage of deployment of the air-bag; FIGURE 11 illustrates a still further stage in the deployment of the air-bag of the second embodiment in which the air-bag is substantially fully inflated;

FIGURE 12 is a schematic cross-sectional illustration showing a safety arrangement in accordance with a third embodiment of the present invention during an initial stage of deployment, in which the air-bag is partially inflated;

FIGURE 13 is a transverse cross-sectional view taken through the air-bag of the third embodiment, in a condition in which the air-bag is laid flat, illustrating a region of an initial re-entrant fold provided in a region of the air-bag;

FIGURE 14 is a view corresponding generally to that of Figure 13 but illustrating an alternative configuration for the fold region;

FIGURE 15 illustrates a further alternative configuration for the fold region;

FIGURE 16 is a view corresponding generally to that of Figure 15 but illustrating a still further configuration for the fold region;

FIGURE 17 is a view corresponding generally to that of Figure 12 illustrating a subsequent stage of deployment, in which a lower region of the air-bag is partially inflated;

FIGURE 18 is a view corresponding generally to that of Figure 17 illustrating a still further stage in the deployment of the air-bag; and

FIGURE 19 is a view corresponding generally to that of Figure 18 illustrating a still further stage of deployment of the third embodiment, in which the air-bag is substantially fully inflated. Referring initially to Figure 1 , there is illustrated a first embodiment of a safety arrangement in accordance with the present invention, showing the arrangement prior to its deployment.

The safety arrangement illustrated in Figure 1 comprises an air-bag module 1 which comprises a housing 2 and which is shown mounted in the upper part of the dashboard 3 of a motor vehicle, generally in front of a front-seat passenger 4 riding in the motor vehicle. The dashboard is shown provided below an inclined windscreen 5 in the normal manner.

The air-bag module 1 further comprises an inflator 6 which may, for example, take the form of a gas generator of a type known per se. The inflator 6 is mounted at the bottom of the housing 2 at a forwardmost position within the housing (relative to the frame of reference defined by the motor vehicle). The inflator 6 is provided in fluid communication with an inflatable air-bag 7 which, in the configuration illustrated in Figure 1 , is shown initially folded, in an un- deployed condition, within the housing 2. A rupturable or removable cover 8 is provided over the housing 2 so as to define a generally flush fitting panel in the top part of the dashboard 3 in an aesthetically pleasing manner. The cover 8, in a manner known per se, is configured to rupture (for example along the predefined split-line) or otherwise open upon actuation of the air-bag module as the air-bag 7 inflates under the action of inflating gas provided by the inflator 6.

As can be clearly seen from Figure 1 , the housing 2 is divided into two distinct regions, namely a forwardmost region 9 in which the inflator 6 is located, and a rearward region 10 which is located between the inflator 6 and the position of the vehicle occupant 4. The forwardmost region 9 and the rearward region 10 of the housing 2 are separated from one another by a generally vertically- extending dividing wall 11 which forms part of a guide 12, the guide 12 being illustrated in more detail, and in perspective view, in Figure 2a. As can be seen from Figure 2a, the upstanding diving wall 11 extends upwardly from a base portion 13 of the guide and terminates with a rearwardly- directed (relative to the frame of reference defined by the motor vehicle) arcuate roof portion 14. In the initial configuration of the guide 12 illustrated in Figures 1 and 2a, the roof portion 14 terminates at a position spaced generally vertically above a small upstanding rear wall 15 which is spaced apart from the forwardmost dividing wall 11.

As can be seen most clearly from Figure 1 , in the un-deployed condition of the safety arrangement, the guide 12 is located entirely within the rearward region 10 of the housing 2, with the roof portion 14 being located below and spaced slightly from the underside of the cover 8.

As can also be seen from Figure 1 , the air-bag 7 is effectively folded into two discrete regions or packages, even though the air-bag 7 itself comprises a single inflatable chamber. The first such package is located in the forwardmost region 9 of the housing, at a position generally above the inflator 6 and in front of the dividing wall 11 of the guide 12. From the uppermost part of the forward package, the fabric of the air-bag extends rearwardly within the housing 2, still under the cover 8, so as to enter the chamber or pocket defined by the initial configuration of the guide 12. It is within this rear chamber or pocket (indicated generally at 16) that the second package defining the folded air-bag is folded.

At this point it is relevant to note that variants of the embodiments illustrated in Figures 1 and 2a are envisaged in which the guide 12 takes a slightly different form. One such form for the guide 12 is illustrated in Figure 2b where it can be seen that the base portion 13 and the small upstanding rear wall 15 of the guide illustrated in Figure 2a have been dispensed with. In such an arrangement, it should be appreciated that the guide 12, when installed in position within the housing 2, will still define a chamber or pocket 16 in substantially identical manner between the guide 12 and the rearmost part of the housing 2, so as to accept the folded rear package part of the air-bag.

The guides 12 may be configured so as to be substantially rigid or, most preferably, semi-rigid and are preferably fabricated from metal or plastics materials. However, it is also envisaged that a fabric guide could be used in certain instances. The particular arrangement illustrated in Figure 1 is configured such that the guide 12 has a degree of flexibility as will become clear hereinbelow.

When using a guide 12 such as that illustrated in Figure 2a, the guide 12 can be secured within the housing 2 by providing a convenient connection between the base portion 13 of the guide and the base wall of the housing and/or by providing some convenient connection also between the ends of the guide 11 and the side walls (not shown) of the housing. In the case of the guide 12 illustrated in Figure 2b, then of course the guide can be secured in position simply by form of a convenient connection between the end regions of the guide and the side walls of the housing.

As can be readily appreciated from a consideration of Figure 1 , the gap between the roof portion 14 of the guide 12 and the rearmost wall 17 defines a relatively restricted opening to the pocket 16 through which the part of the air- bag 7 adjoining the two distinct folded packets extends. This restricted opening, as will become clear below, serves to restrain the rearmost folded packet during deployment of the air-bag.

Figure 3 illustrates the safety arrangement of the first embodiment during an initial stage of deployment in which the air-bag 7 is partially inflated. As can be seen, the inflator 6 has been actuated so as to provide inflating gas, the gas being directed immediately into the forwardmost folded packet, thereby inflating that region of the air-bag so as to define an upper region 18 of the air- bag. As can be seen in Figure 3, in this condition, the upper region 18 has become inflated so as to bear against the undersurface of the windscreen 5 and is shown having been contacted by the head of the occupant 4 whose torso has been moved forwardly relative to the dashboard 3 under its inertia in an accident situation. However, at this stage in the deployment of the air-bag 7, the rear packet of the air-bag, which was initially folded into the chamber 16 in the rear part of the housing, has been restrained from inflation because of its tortuous path extending through the restricted opening 19 into the chamber 16.

However, when the upper region 18 of the air-bag becomes sufficiently inflated so as to achieve a predetermined volume generally as illustrated in Figure 3, further supply of gas from the inflator 6 into the interior of the air-bag 7 causes the rearmost folded packet of the air-bag to be pulled outwardly through the restricted opening 19 for subsequent inflation. Indeed, this withdrawal of the rearmost folded packet portion of the air-bag is shown just beginning in Figure 3 where it can also be seen that, under the pulling action applied to the rear folded part of the air-bag, by virtue of the uppermost inflated region 18, the guide 12 is deformed slightly so that its roof portion 14 is lifted, thereby widening the initially restricted aperture 19. This allows subsequent easier withdrawal of the rear folded part of the air-bag.

Figure 4 shows a subsequent stage in the continued deployment of the safety arrangement of the first embodiment and here it can be seen that most of the initial rearward folded packet of the air-bag has been withdrawn from the pocket 16 although there is still a relatively large unfolded region lying on top of the dashboard as indicated generally at 20. Nevertheless, it can be seen that the rear packet has begun to be inflated so as to define a downwardly- extending lower region 21 of the inflating air-bag which extends downwardly from the upper region 18 and lies between the thorax/abdomen of the occupant 4, thereby providing protection to the occupant from impact with the dashboard 3.

Figure 5 illustrates a further stage in the deployment of the air-bag in which the lower region 21 has become further inflated, whilst Figure 6 illustrates the air- bag 7 in the fully deployed condition in which the initially folded rearward packet of the air-bag has become completely unfolded so as to define the completely inflated lower region 21 of the air-bag.

It should therefore be appreciated that the above-described safety arrangement serves to restrain the lower region 21 of the air-bag from deployment until such time as the upper region 18 has become sufficiently inflated so as to bear against the windscreen 5 and contact the head of the occupant 4, whereupon continued deployment of the air-bag allows subsequent inflation of the lower region 21. This configuration thus provides an inflation characteristic which is effective in preventing, or at least significantly reducing, injuries to an "out-of-position" occupant sitting too close to the dashboard 3 as a result of the phenomenon commonly known as "bag-slap", because it provides an arrangement in which the upper region 18 of the air- bag is inflated first so as to provide relatively early protection to the head of the occupant 4, whereafter the lower region of the air-bag 21 can then be inflated between the thorax/abdomen of the occupant 4 and the dashboard 3. This inflation characteristic avoids very fast initial inflation of the air-bag directly towards the occupant's torso.

Figure 7 illustrates, in schematic side view, an alternative form of guide 12 in which the dividing wall 11 , rather than being provided as a substantially planar vertical wall, is provided with a number of corrugations 22. These corrugations 22 can thus be seen to extend into the pocket 16 defined within the confines of the guide 12. As will be appreciated, when the initially-folded rear packet of the air-bag (eventually to define the lower region 21 upon full deployment) is tightly packed into the pocket 16, parts of the air-bag will become packed within the corrugations 22. It will therefore be appreciated that the corrugations 22 thus serve to further restrain this region of the folded air-bag from deployment, thereby supplementing the restraint function of the present invention.

A safety arrangement in accordance with the second embodiment of the present invention is illustrated in Figures 8 to 11.

Referring initially to Figure 8, the safety arrangement of this embodiment again comprises an air-bag module 1 which in turn comprises a housing 2 mounted in the upper part of the dashboard 3 of a motor vehicle. The air-bag module again comprises an inflator 6 which is located at the bottom and front region of the housing 2 and which is provided in fluid communication with the inflatable air-bag 7.

Figure 8 illustrates the safety arrangement of this embodiment during an initial stage of deployment in which the air-bag 7 as a whole is only partially inflated but such that an upper region 18 of the air-bag has become inflated to such a degree that it bears against the undersurface of the windscreen 5 of the motor vehicle and has begun to bear against the head of a seat occupant 4.

In this arrangement, a pocket is defined by an internal pouch 23 which is provided within the air-bag 7. The pouch 23 defines a restricted opening 24 (visible at its lowermost region in the configuration illustrated in Figure 8). A region of the air-bag 7, intended to define a lowermost inflatable region when the air-bag is fully deployed, is initially tightly folded within the pouch 23. Although not illustrated, when the air-bag 7 is completely packed within the housing 2 prior to deployment, the pouch 23, with the tightly-folded region of the air-bag within it, is tightly packed in the rear part of the housing 2, between the inflator 6 and the occupant 4, and the region of the air-bag 7 which is seen to define the upper inflatable region 18 is then packed into the housing 2 in the region above the inflator 6.

Because the rear region of the folded air-bag is initially tightly folded within the pouch 23 and passes through the restricted opening 24, during the initial stages of deployment, the rear part of the packed air-bag is restrained from deployment so that during the initial stages of deployment, only the upper region 18 becomes significantly inflated. However, in the condition illustrated in Figure 8, it will be seen that the upper portion 18 has become inflated so as to impinge on the undersurface of the windscreen 5 and begin to contact the head of the seat occupant 4, thereby achieving a predetermined volume. Further inflation of the upper region 18 beyond this predetermined volume serves to pull out the initially-folded rear part of the air-bag from the pouch 23 through the restricted opening 24, thereby allowing this region of the air-bag also to inflate as illustrated in Figure 9, thereby defining the lower region 21 to the inflating air-bag 7. However, as illustrated in Figure 9, although the lower region 21 of the air-bag has begun to be inflated between the occupant 4 and the dashboard 3 in generally the same manner as in the previous embodiment, there is still a substantial extent of the air-bag tightly folded within the pouch 23.

Figure 10 illustrates a still further stage in the deployment of this embodiment of the present invention and it will be seen from Figure 10 that the volume of the lower inflatable region 21 of the air-bag has increased significantly, although there is still a small folded region located within the pouch 23. Figure 11 , on the other hand, illustrates the substantially fully-deployed condition of this embodiment from which it will be seen that the region of the air-bag originally folded within the pouch 23 has been completely removed from the pouch 23 such that the pouch 23 is entirely empty but, of course, remains within the inflated air-bag 7. As will be appreciated, it is important for the pouch 23 to be made from flexible material so that it can initially be tightly packed within the air-bag housing 2, and also so that the pouch 23 has no significant mass in view of the fact that it remains within the air-bag 7 upon substantially complete inflation of the air- bag. In preferred embodiments, the pouch 23 is made from very thin shrink foil or rubberised foil, although other convenient materials could be used such as fabric materials. Furthermore, although this embodiment has been described above with reference to the pouch 23 remaining substantially intact but being provided with a restricted opening through which the initially folded region of the air-bag located in the pouch is withdrawn from the pouch, this embodiment could be modified so as to be provided with a rupturable pouch configured to rupture as the pulling force serving to withdraw the folded region of the air-bag from the pouch increases, thereby releasing the folded region of the air-bag so as to inflate, thereby defining the lower region 21.

Figure 12 illustrates, during an initial stage of deployment, a safety arrangement in accordance with a third embodiment of the present invention. In this arrangement, an air-bag module is again provided comprising a housing 2 mounted in the upper part of a dashboard 3, with an inflator 6 provided in the lower, forwardmost region of the housing 2, the inflator 6 being provided in fluid communication with an inflatable air-bag 7.

Figure 12 illustrates the air- bag 7 during an initial stage of deployment in which an upper region 18 of the air-bag has been inflated so as to bear against the undersurface of the windscreen 5 and contact the head of the seat occupant 4.

In this embodiment, the lower, rearmost region of the air-bag is folded in on itself so as to define a single re-entrant fold 25 which extends across significant transverse extent of the air-bag. The re-entrant fold 25 is initially tightly packed within the rear part of the housing 2, between the occupant 4 and the inflator 6, with the upper inflatable part 18 of the air-bag 7initially being tightly packed into the housing 2 on top of the inflator 6.

As will be appreciated, formation of the re-entrant fold 25, across a significant transverse extent of the air-bag 18 results in two layers of the air-bag fabric effectively lying against one another along the extent of the fold. These layers of fabric are connected together in the manner of a surface connection in order to initially secure the fold, thereby restraining the fold against unfolding. Figure 13 illustrates a transverse cross-section taken through the air-bag in a lard-flat condition where one possible option for this surface connection securing the re-entrant fold 25 is illustrated. The air-bag illustrated in Figure 13 can be seen to comprise a main panel region 26, an head panel region 27 and a side panel 28. The large area indicated by the dotted lines defines the region of the reentrant fold 25 which is secured and in this arrangement the fold is secured by a series of parallel lines of stitching 29 which define a field of rupturable tear stitches which extend across the side panels 28, the head panel 27 and the main panel 26. As will be appreciated, the lines of tear-stitching 29 are configured to rupture when sufficient tear forces are applied to the re-entrant fold 25, thereby opening up the fold and allowing the region of the air-bag defining the fold to become unfolded and inflate.

Figure 14 illustrates an alternative configuration for the field of tear stitches 29, with the field this time extending only over the main panel 26 and the head panel 27, leaving the regions of the side panels 28 within the re-entrant fold 25 unsecured.

Figure 15 illustrates a generally U-shaped configuration for the field of tear stitches within the re-entrant fold 25, and Figure 16 illustrates a still further configuration for the field of tear stitches comprising a series of circular-shaped arrays of the tear stitches 29. However, it should be appreciated that this embodiment of the invention could also be implemented without the use of tear stitches, instead replacing the tear stitches with another form of convenient surface connections such as, for example, an adhesive layer provided between the adjacent fabric layers defining the fold, serving initially to connect the two layers across the fold in order to secure the fold but configured so as to tear apart upon the application of a sufficiently large tear force to the re-entrant fold.

Figure 17 is a view corresponding generally to that of Figure 12 but shows the safety arrangement of this embodiment during a subsequent stage of deployment in which the upper region 18 has been further inflated beyond its predetermined volume, thereby applying a tear force to the re-entrant fold 25.

The result is that the re-entrant fold 25 is torn open from its lower end such that the region of the air-bag initially folded into the re-entrant fold 25 begins to inflate downwardly as indicated by the arrows A so as to begin to define the lower abdominal region 21 of the air-bag.

Continued inflation of the air-bag, as illustrated in Figure 18, continues to apply the tear force to the re-entrant fold 25, thereby continuing to rupture the tear stitches or adhesive layer provided within the re-entrant fold 25 such that the lower region 21 continues to inflate, and such that the length of the remaining re-entrant fold 25 becomes correspondingly reduced. Figure 19 illustrates this arrangement in a substantially fully deployed condition in which the lower region 21 has become completely unfolded from the re-entrant fold 25 so as to define its full volume between the seat occupant 4 and the dashboard 3.

It should therefore be appreciated that all of the above-mentioned embodiments thus comprise arrangements confined to restrain the lower region 21 of the air-bag, thereby substantially preventing inflation of the lower region during the initial stages of deployment of the safety arrangement, until such point as the upper region 18 becomes sufficiently inflated to a predetermined volume, whereafter continued inflation serves to forcibly withdraw or pull out the initially-packed lower region of the air-bag against the restraining action of the restraint arrangement. This serves to ensure that the initial inflation of the air-bag is focused on the upper region 18 to provide the quick formation of an inflated region to provide protection to the head of a seat occupant, but without directing a large volume of air-bag directly against an out-of-position torso of the seat occupant. Once the upper region of the air- bag is sufficiently inflated, the lower region then deploys more safely between the occupant's torso and the dashboard of the vehicle.

When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

1. A safety arrangement for a motor vehicle, the safety arrangement comprising: an airbag module (1) having an inflatable airbag (7) in fluid communication with an inflator (6) configured to inflate the airbag, the airbag having an upper region (18) arranged to lie substantially adjacent the windscreen (5) of the vehicle on inflation, and a lower region (21) in fluid communication with the upper region (18), wherein the safety arrangement further comprises an inflation-restraint arrangement configured to restrain the lower region (21) so as to substantially prevent inflation of said lower region until said upper region is inflated to a predetermined volume.

2. A safety arrangement according to claim 1 , wherein said lower region (21 ) of the airbag is arranged to provide protection to the thorax or abdomen of a vehicle occupant (4) when inflated.

3. A safety arrangement according to claim 1 , or claim 2, wherein said inflation-restraint arrangement comprises at least one fold (25) formed in the lower region of the airbag, and means (29) configured to resist unfolding of the or each fold until said upper region (18) is inflated to said predetermined volume.

4. A safety arrangement according to any preceding claim, wherein said inflation-restraint arrangement comprises a restraint-pocket (16) in which the lower region (21) of the airbag is initially folded.

5. A safety arrangement according to claim 4, wherein said pocket defines a restricted opening (19,24) for the withdrawal of said lower region (21) therethrough.

6. A safety arrangement according to claim 4 or claim 5, wherein said pocket (16) is defined between part of a housing (2) of the airbag module and a guide (12), the guide being located between said part of the housing and the inflator (6).

7. A safety arrangement according to claim 6, wherein the guide (12) is flexible.

8. A safety arrangement according to claim 7, wherein the guide (12) is made of plastics material.

9. A safety arrangement according to claim 7, wherein the guide (12) is metal.

10. A safety arrangement according to any one of claims 6 to 9, wherein at least part of the guide is corrugated (22).

11. A safety arrangement according to claim 4 or claim 5, wherein the pocket takes the form of a pouch (23) located inside the airbag (7), and wherein the lower region (21) is initially folded inwardly of the airbag, into the pouch (23).

12. A safety arrangement according to claim 11 as dependant upon claim 4, wherein the pouch (23) is configured to rupture upon inflation of the upper region (18) to said predetermined volume, in order to release the lower region (21) of the airbag for inflation.

13. A safety arrangement according to claim 11 as dependant upon claim 5, wherein the pouch (23) is configured to remain substantially intact during inflation of the airbag (7), such that the lower region (21) is pulled out from the pouch, through said restricted opening (24) to become released. ZO

14. A safety arrangement according to claim 3, wherein said inflation- restraint arrangement comprises a re-entrant fold (25) formed in the lower region (21) of the airbag, and means (29) to initially secure the fold so as to prevent unfolding of the lower region (21) until the upper region (18) becomes inflated to said predetermined volume.

15. A safety arrangement according to claim 14, wherein said means comprises a plurality of tear-stitches (29) configured to rupture as the upper region reaches said predetermined volume, thereby permitting the re-entrant fold (25) to unfold.

16. A safety arrangement according to claim 14, wherein said means comprises adhesive configured to release the fold (25) as the upper region (18) reaches said predetermined volume, thereby permitting the re-entrant fold (25) to unfold.

17. A safety arrangement substantially as hereinbefore described with reference to and as shown in Figures 1 to 7 of the accompanying drawings.

18. A safety arrangement substantially as hereinbefore described with reference to and as shown in Figures 9 to 11 of the accompanying drawings.

19. A safety arrangement substantially as hereinbefore described with reference to and as shown in Figures 12 to 17 of the accompanying drawings.

20. Any novel feature or combination of features disclosed herein.