WO2008069704A1

WO2008069704A1 - An air-bag module

Info

Publication number: WO2008069704A1
Application number: PCT/SE2006/001388
Authority: WO
Inventors: Thomas Reiter; Karl-Heinz Sommer; Klaus-Peter KÜHNE; Marcus Weber; Marc Schock; Jörg ALBERT
Original assignee: Autoliv Development Ab
Priority date: 2006-12-07
Filing date: 2006-12-07
Publication date: 2008-06-12

Abstract

An air-bag module (1) is disclosed for a motor vehicle safety device which comprises a housing (2) having a base (3) and an opening (20). The housing contains an inflatable fabric air-bag (14) and an inflator. The air-bag (14) is provided in the form of an initially -folded package which comprises a pair of fold packets (21, 22), the arrangement being characterised by the fold packets (21, 22) being separated from one another by a fabric divider (which can be a separate fabric divider or indeed part of the air-bag itself or the housing). The divider is tucked inwardly of the air-bag package and extends from the region of the base (3) of the housing towards the opening (20).

Description

Title: AN AIR-BAG MODULE

Description of Invention

THE PRESENT INVENTION relates to an air-bag module and, more particularly, relates to an air-bag module for a motor-vehicle safety device.

It is now very widely known to provide a motor vehicle with one or more safety devices comprising an inflatable air-bag in order to provide protection to the driver and/or passengers of the motor vehicle in the event of an accident. For example, it is now very common for motor vehicles to be provided with an air- bag in the steering wheel in order to provide protection to the driver of the motor vehicle, and also with an air-bag in the region of the dashboard in front of the front passenger seat of the vehicle in order to provide protection to the front seat passenger. However, one problem with early air-bag designs was that of ensuring safe deployment of the air-bag into the space in front of the driver or passenger in the event that the driver or passenger was not located in the "ordinary" sitting position. This problem has become known as the "out-of- position" problem.

Because of the very short time period within which an air-bag must inflate in order to provide sufficient deployment to a person sitting in the normal position within the motor vehicle, the air-bags are inflated with a very aggressive flow of gas, thereby ensuring very fast inflation of the air-bag. Jf, however, the driver or passenger is sitting "out-of-position" (for example is leaning forwardly or to one side, perhaps to access the motor vehicle's glove compartment or centre console compartment), then a quickly-inflating air-bag can cause serious injury to the out-of-position vehicle occupant. It has therefore become more recent practice to design air-bags, and more particularly to design their folding patterns, so that an initial region of the air-bag inflates relatively quickly and aggressively, so as to adopt an appropriate position within which to restrain the seat occupant, but in which other parts of the air-bag are inflated more slowly and with a carefully controlled unfolding action intended to impinge more appropriately and safely against the out-of-position seat occupant.

In this regard, it has been recognised that it is advantageous to use an air-bag folding technique which is effective to separate the folded air-bag into two separate portions or fold packets. A first portion or fold packet is arranged so that it is pushed out of the air-bag housing, opening the air-bag cover, under the action of inflating gas from an inflator such as a gas generator. A second portion or fold packet is then pulled out of the air-bag housing by the first portion. The movement of the pushed portion of the air-bag is more aggressive than that of the pulled portion and so it is desirable to make the first portion relatively small, thereby reducing the risk of injuries to an out-of- position seat occupant.

In order to divide an air-bag folded in this manner into two portions, it is known to use a rigid gas deflector, for example in the form of a metal plate fixed to the housing or the gas generator of an air-bag module. Such an arrangement is disclosed in US 7,011 #36B2. Whilst the rigid dividing wall of such prior art arrangements are effective in dividing the folded air-bag package into two distinct fold-packets or regions as discussed above, such arrangements do suffer from significant disadvantages such as weight increases attributable to the fixed metal dividing plate and associated cost issues. Also, there can be instances in which it is preferable to provide an air-bag module with a flexible fabric housing rather than a more rigid plastic moulding or metal housing and, in such arrangements, it can be very difficult properly to attach a rigid metal dividing wall such as that disclosed in the prior art. It is an object of the present invention to provide an improved air-bag module for a motor vehicle safety device.

Accordingly, the present invention provides An air-bag module for a motor vehicle safety device, the module comprising : a housing having a base and an opening, and containing an inflatable fabric air-bag; and an inflator configured to inflate the air-bag through the opening, wherein the air-bag is provided in the form of an initially folded package comprising a pair of fold packets characterised in that said fold packets are separated from one another by a fabric divider tucked inwardly of the air-bag package and extending from the region of base of the housing towards the opening.

Preferably, the fabric divider is separate from the air-bag and from the housing.

Advantageously, the fabric dividers is secured relative to the housing

Conveniently, the fabric divider is located outside the air-bag, but at least partly within the housing

Preferably, the fabric divider is formed inside the air-bag.

Advantageously, the fabric divider forms part of the air-bag.

Conveniently, the air-bag module has a housing made from fabric and wherein the fabric divider forms part of the housing.

Preferably, the fabric divider is formed in the manner of a re-entrant fold so as to extend inwardly of the air-bag package. Advantageously, at least a region of said re-entrant fold is stitched such that opposed regions of the divider are secured to one another.

Conveniently, the housing is provided with an aperture or recess to receive a tool for insertion into the housing, around which tool the re-entrant fold defining the divider is formed.

Preferably, an aperture is formed through the base region of the housing for the insertion of said tool.

Advantageously, said aperture or recess is formed in the housing substantially adjacent said inflator.

Conveniently, the air-bag is produced by a method incorporating the steps of : inserting a tool into said aperture or recess; creating said re-entrant fold over said tool and folding the air-bag to create said fold packets; and subsequently removing said tool from the aperture or recess.

Preferably, the air-bag is produced by a method incorporating the steps of : creating said re-entrant fold over a tool and folding the air-bag to create said fold packets; and subsequently removing said tool from the re-entrant fold.

Advantageously, said tool has a plurality of spaced apart fingers and wherein said method includes the step of stitching together opposed regions of said divider at positions between said fingers, before removal of said tool.

So that the invention may be more readily understood, and so that further features thereof may be appreciated, embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings in which :- FIGURE 1 is a schematic cross-sectional view taken through an air-bag module in accordance with the first embodiment of the present invention, showing an initial stage during production of the air-bag module;

FIGURE 2 is a view corresponding generally to that of Figure 1 illustrating a subsequent stage of the production of the air-bag module;

FIGURE 3 is a view corresponding generally to that of Figure 2 illustrating a further stage in the production of the air-bag module;

FIGURE 4 is a view corresponding generally to that of Figure 3 illustrating a still further stage in the production of the air-bag module;

FIGURE 5 is a view corresponding generally to that of Figure 4 illustrating a further step during the production of the air-bag module;

FIGURE 6 is a schematic cross-sectional view taken through an air-bag module in accordance with another embodiment of the present invention, showing a stage during the production of the air-bag module;

FIGURE 7 is a schematic cross-sectional view through an air-bag module in accordance with a third embodiment of the present invention, showing a stage during the production of the air-bag module;

FIGURE 8 is a schematic cross-sectional view through an air-bag module in accordance with a fourth embodiment of the present invention, illustrating a stage during the production of the air-bag module; FIGURE 9 is a schematic cross-sectional view taken through an air-bag module in accordance with a fifth embodiment of the present invention, illustrating a stage during the production of the air-bag module;

FIGURE 10 is a schematic cross-sectional view taken through an air-bag module in accordance with a sixth embodiment of the present invention, illustrating a stage during the production of the air-bag module;

FIGURE 11 is a schematic cross-sectional view taken through an air-bag module in accordance with a seventh embodiment of the present invention, illustrating a stage during the production of the air-bag module;

FIGURE 12 is a schematic cross-sectional view taken through an air-bag module in accordance with an eighth embodiment of the present invention, illustrating an early stage during the production of the air-bag module;

FIGURE 13 is a view corresponding generally to that of Figure 12, illustrating a subsequent step during the production of the air-bag module of the eighth embodiment;

FIGURE 14 is a schematic cross-sectional view taken through an air-bag module in accordance with ninth embodiment of the present invention, illustrating a stage during the production of the air-bag module;

FIGURE 15 is a cross-sectional view, taken along line A-A of Figure 14, illustrating a tool used during the production of the air-bag module of Figure 14;

FIGURE 16 is a schematic cross-sectional view, similar to that of Figure 14, but illustrating an air-bag module of a slightly modified further embodiment; FIGURE 17 is a schematic cross-sectional view taken through an air-bag module in accordance with an eleventh embodiment of the present invention, illustrating a stage during the production of the air-bag module; and

FIGURE 18 is a schematic cross-sectional view through an air-bag module in accordance with a twelfth embodiment of the present invention, illustrating a stage during the production of the air-bag module.

Referring in detail initially to Figures 1 to 5, an air-bag module in accordance with a first embodiment of the present invention will be described with reference to various stages during its production.

As illustrated in Figure 1 , the air-bag module 1 comprises a housing 2 which is shown to comprise a base 3 and a pair of generally upwardly, and slightly outwardly, directed sidewalls 4, 5. The base 3 comprises a generally planar main portion which is illustrated in the drawings as being substantially horizontal, and at one end is provided with an upwardly-inclined region 6 extending to the left-hand sidewall 5. It will therefore be seen that the left- hand sidewall 5 is somewhat shorter than the right-hand sidewall 4. At the upper edge of each sidewall 4, 5, the housing is provided with a pair of outwardly-directed flanges 7.

The air-bag module housing 2 is preferably made of metal material, such as sheet metal, although it should be appreciated that in other variants, the housing 2 can be moulded from plastics material. Although not illustrated in Figures 1 to 5, which illustrate the air-bag module 1 in transverse cross- section, the ends of the housing 2 are closed by respective end walls extending between the sidewalls 4, 5.

The inclined base region 6 is provided with a mounting aperture 8 which is sized and shaped to receive therethrough part of an inflator 9 such as a standard gas generator of the type commonly used in air-bag modules. The inflator 9 has an outlet region 10 which extends through the mounting aperture 8 so as to lie within the inner chamber 11 of the housing 2. The outlet region 10 of the inflator 9 is provided with a series of gas outlet apertures 12 (only one shown in Figure 1) which are arranged for the expulsion of gas upon actuation of the inflator 9.

Extending outwardly from the outlet region 10 is a mounting flange 13 which is configured to conform to the inner profile of the base 3 in the region of the inclined part 6.

Inflatable air-bag 14 is provided which is flexible and is preferably made from fabric material. The air-bag 14 is illustrated in Figure 1 in a substantially unfolded condition prior to complete assembly of the air-bag module. The air- bag 14 defines an inner volume 15 and is provided with a gas inlet aperture which, although not clearly visible in Figure 1 , is of a size and form appropriate to fit closely over the outlet region 10 of the inflator 9 so as to be trapped between the inclined region 6 of the housing base and the mounting flange 13 of the inflator 9. The inflator 9 is secured to the housing 2 in any convenient manner sufficient to clamp or otherwise secure the region of the air-bag surrounding the gas inlet aperture between the inclined region 6 of the housing 2 and the mounting flange 13 of the inflator 9. It will thus be seen that the outlet region 10 of the inflator 9, and its associated gas outlet apertures 12 is located within the inner volume 15 of the air-bag 14 for inflation of the air-bag upon actuation of the inflator.

A fabric divider 16 is provided which, in this embodiment, takes the form of a separate, discrete sheet of fabric material which is secured in the region of one side.edge (indicated generally at 17) by being clamped between the air-bag 14 and the base 3 by virtue of the clamping action of the inflator mounting flange 13. It should be appreciated, however, that other convenient forms of securement could be used to secure the fabric divider 16 relative to the housing 2.

As can be seen from Figure 1 , the fabric divider 16 is provided outside the air- bag 14 and is located between the air-bag 14 and the housing 2.

The base 3 of the housing 2 is provided with a relatively small aperture 18 which can take any convenient form such as, for example, an elongate slot running at least part-way along the length of the housing 2. Figure 1 illustrates a folding tool 19 positioned adjacent the aperture 18 and aligned therewith for subsequent insertion through the aperture 18. It should be appreciated that the tool 19 will not actually form part of the fully-fabricated air-bag module.

Turning now to consider the subsequent production step illustrated in Figure 2, it can be seen that the folding tool 19 has been inserted a significant way through the aperture 18 in the base 3, in a substantially vertical direction (as indicated by arrow A) towards the opening 20 of the housing 2 defined between the upper edges of the sidewalls 4, 5 and the two end walls (not shown). With the tool 19 inserted through the aperture 18 in this manner, the sheet of fabric defining the fabric divider 16 is then formed over the tool 19 in the manner of a re-entrant fold so as to extend inwardly of the inner chamber

11 from the region of the base 3 towards the opening 20.

As illustrated in Figure 3, once the fabric divider 16 has been folded over the tool 19 as illustrated in Figure 2, an initial region of the air-bag 14 is then folded into the region of the inner chamber 11 located on the opposite side of the tool 19 to the inflator 9 and is tightly packed into this region of the chamber 11 as indicated by arrow B in Figure 3. There is thus formed a fold packet 21 in this region of the inner chamber 11. Once the fold packet 21 has been packed into the inner chamber 11 , on one side of the tool 19, the remaining unfolded part of the air-bag 14 is then folded and packed into the region of the inner chamber 11 located on the other side of the tool as indicated by arrow C in Figure 4 so as to define another fold packet 22 located in the same region of the chamber 11 as the outlet region 10 of the inflator y

When the air-bag 14 has been fully folded into the inner chamber 11 of the housing 2 so as to define the two fold packets 21, 22, the tool 19 can be withdrawn from the aperture 18 as illustrated by arrow D in Figure 5. Because of the tight packing of the air-bag within the inner chamber 11 , withdrawal of the tool 19 in this manner leaves the re-entrant fold in the fabric divider 16 substantially undisturbed. However, in variants of the invention, it is envisaged that such withdrawal of the tool 19 could be further facilitated, without disturbing the re-entrant fold of the fabric divider 16, by providing a low friction coating on the underside of the sheet of fabric defining the divider 16 and/or a relatively high friction coating on the upper surface of the sheet. The low friction coating would thus facilitate easy withdrawal of the tool 19 from the reentrant fold formed in the divider 16, whilst the high friction coating would ensure that the re-entrant fold is substantially held in place against the folds formed in the air-bag.

Having regard to Figure 5, it should therefore be appreciated that, after withdrawal of the folding tool 19, the resulting air-bag module is provided with the air-bag 14 formed into a folded package comprising a pair of fold packets 21 , 22. The two fold packets 21 , 22 are separated from one another by the fabric divider 16 which, by virtue of the re-entrant fold is effectively tucked inwardly of the air-bag package and extends from the region of the base 3 towards the opening 20 (the opening 20 being closed by an openable or puncturable cover in the final module). Upon receipt of an appropriate crash signal from a crash sensor (not shown), the inflator 9 is actuated, thereby providing an aggressive flow of gas through its outlet apertures 12 into the region of the inner chamber 11 in which the fold packet 22 is folded. This flow of gas thus serves initially to inflate the region of the air-bag 14 defined by the fold packet 22 but, by virtue of the presence of the fabric divider 16, the flow of gas is prevented from directly entering the region of the air-bag defining the other fold packet 21. The region of the air- bag defined by the fold packet 22 is thus pushed from the housing 2 under the action of the inflating gas and, as this region of the air-bag becomes inflated, it serves to pull the region of the air-bag defined by the other fold packet 21 from the housing 2, thereby allowing that region of the air-bag 21 to unfold and become substantially fully inflated.

Although the air-bag module of the present invention has been described in detail with reference to the arrangement illustrated in Figures 1 to 5, it should be appreciated that various modifications can be made to the arrangement, resulting in alternative embodiments which still fall within the scope of the present invention. Several such alternative embodiments will now be described with reference to the remaining drawings. Several of the component parts in the alternative embodiments are equivalent to those illustrated in the arrangement of Figures 1 to 5 and so the same reference numerals will be used to identify any such components.

In the arrangement of Figure 6, the inflator 9 is illustrated mounted through an aperture provided in the left-hand sidewall 5, just above the inclined region 6 of the base 3. Nevertheless, it should be appreciated that the inflator 9 is still mounted in the general region of the base 3.

The principal difference between the arrangement of Figure 6 and that of Figures 1 to 5 is that the aperture 18 for the insertion of the tool 19 is provided in the inclined region 6 of the base. As can also be seen, the tool 19 is of arcuate form and is inserted into the inner chamber 11 and withdrawn from the inner chamber 11 along a generally arcuate path as indicated by arrow E. Nevertheless, the air-bag module of Figure 6 is still produced in accordance with a method having the same general steps as described above with reference to the embodiment of Figures 1 to 5, namely : insertion of the tool 19 along the curved path E; formation of the fabric deflector 16 into the form of a re-entrant fold over the tool 19; creation of the first fold packet 21 into the region of the chamber 11 located on the opposite side of the tool 19 to the gas generator 9; subsequent formation of the second fold packet 22 and then withdrawal of the tool 19 along the curved path E so as to leave behind the reentrant fold in the fabric divider 16.

It can be seen that the re-entrant fold 16 formed by the curved tool 19 curves around the end of the outlet region 10 of the inflator 9 and serves to prevent the direct flow of gas from the outlet apertures 12 into the region of the air-bag defined by the first fold packet 21. The second fold packet 22 is packed into the inner chamber 11 so as to lie above the first fold packet 21 but nevertheless has a region in direct fluid communication with the outlet apertures 12. Thus, in this embodiment, the fabric divider 16 again serves to separate the two fold packets 21 , 22 from one another such that, upon actuation of the inflator 9, gas is directed into the second fold packet 22 so as to push that region of the air-bag from the chamber. Inflation of the air-bag formed by the second fold packet 22 serves to pull the region of the air-bag defined by the other fold packet 21 from the chamber 11.

The arrangement of Figure 7 is configured such that the base 3 of the module housing 2 is stepped so as to define a substantially horizontal mounting region 23 at a level spaced above the lowermost region 3 of the base. The inflator 9 is mounted to the housing 2 by virtue of receipt through a mounting aperture provided in the mounting region 23. In this arrangement, the tool insertion aperture 19 is provided at the juncture between the raised mounting region 23 of the housing and the inclined region 6 of the base, and in this arrangement, the folding tool 19 is inserted and withdrawn through the aperture 18 in a substantially vertical manner, along the path illustrated by arrow F.

However, the most significant difference between the embodiment of Figure 7 and those of Figures 1 to 5, and Figure 6, is that in the embodiment of Figure 7, the separate and discrete fabric divider 16 has been dispensed with. Instead, in this arrangement, a region of the air-bag 14 itself effectively forms the fabric deflector until such time as the air-bag becomes substantially fully inflated.

Prior to folding and packaging of the air-bag 14 in the embodiment of Figure 7, the folding tool 19 is inserted through the aperture 18 so as to adopt the position illustrated in Figure 7. With the tool 19 in this folding position, a region of the air-bag is initially folded and packed into the region of the chamber 11 located on the opposite side of the tool 19 to the outlet region 10 of the inflator 9. There is thus formed a first fold packet 21 which is located in the region of the chamber 11 having the largest vertical extent. Because the fold packet 21 is formed with the tool 19 in place as illustrated in Figure 7, a region of the air- bag is thus formed into a re-entrant fold 24, over the tool 19. This re-entrant fold region 24 effectively defines a fabric divider having the same function as the fabric dividers 16 of the previously-described embodiments.

Once the re-entrant fold 24 and the first fold packet 21 have been formed as described above, the remaining part of the air-bag 14 is then folded and packaged into the chamber 11 , in the region above the inflator 9 so as to form the second fold packet 22. Once this has been done, the folding tool 19 can be withdrawn through the aperture 18, leaving behind the re-entrant fold 24 in the air-bag which thus defines the fabric divider which is effectively tucked inwardly of the complete air-bag package, extending from the region of the base towards the opening of the housing 2. Because of the presence of the re-entrant fold 24, and its orientation relative to the outlet region 10 of the inflator 9, flow of gas from the outlet apertures 12 is directed only into the second fold packet 22 and thus, upon actuation of the inflator 9, the fold packet 22 is pushed from the chamber, whilst the fold packet 21 is pulled from the chamber under the inflating action of the first fold packet 22.

The embodiment illustrated in Figure 8 is similar to that illustrated in Figure 7 in the sense that the fabric divider is formed by a re-entrant fold 24 formed in a region of the air-bag 14 itself.

In the arrangement of Figure 8, the inflator 9 is provided mounted through a mounting aperture in the sidewall 5 of the housing 2, although it should be appreciated that the inflator 9 is effectively nevertheless still located in the region of the base 3. In this arrangement, the mounting flange 13 provided around the outlet region 10 of the inflator 9 has a modified form having an upwardly-directed deflector part 25 which curves around the lower, and right- hand end region of the outlet area 10 of the inflator 9.

In the arrangement of Figure 8, it can be seen that the folded air-bag package actually comprises three distinct fold packets. The first fold packet 21 is formed with the folding tool 19 in place and is packed into the right-hand-most region of the inner chamber 11 , on the opposite side of the tool 19 to the inflator 9. The second fold packet 22 is then created, on the opposite side of the tool 19 to the first fold packet 21 , and is packed into the region of the chamber 11 located between the deflector 25 and the folding tool 19. The third fold packet 26 (which in the arrangement illustrated in Figure 8 takes the form only of one zig-zag fold) is created and is packed into the right-hand region of the chamber 11 , immediately above the outlet region 10 of the inflator 9 and so as to extend across the top of the second fold packet 22. When the three fold packets have been created in this manner, the folding tool 19 can be withdrawn, leaving behind the re-entrant fold 24 defining the fabric divider as part of the air-bag 14 itself.

Upon actuation of the inflator 9, gas is initially directed from the outlet apertures 12 in an upwards direction by virtue of the upwardly-directed configuration of the deflector part 25, so as to inflate, and hence push the third fold packet 26 out from the housing 2. The presence of the deflector part 25 prevents significant flow of gas from the outlet apertures 12 directly into the second fold packet 22 and thus the fold packet 22 only becomes significantly inflated when it is pulled out from the housing 2 under the action of the inflating third fold packet 26. As the second fold packet 22 becomes inflated it, in turn, pulls the first fold packet 21 from the air-bag housing 2.

Turning now to consider Figure 9, a further alternative embodiment is disclosed which represents a modification of the arrangement described above with reference to Figures 1 to 5. Indeed, as can be readily seen from Figure 9, the construction of the housing 2 and the location of the inflator 9 is largely identical to the arrangement of Figures 1 to 5 and so will not be described in further detail here. However, the principal difference between the arrangement of Figure 9 and that of Figure 1 to 5 is that the base region 3 of the housing is not provided with an aperture 18 in the same manner as the arrangement of Figures 1 to 5. Instead, the arrangement of Figure 9 is provided with an aperture in the form of a slot formed through one of the end walls (not shown) of the housing 2 for the insertion of a folding tool 19 into the inner chamber 11 in a direction illustrated into the page as viewed in Figure 9.

With the folding tool 19 inserted (into the page as viewed in Figure 9) into the inner chamber 11 and adopting the position illustrated in Figure 9, the fabric divider 19 is again formed into a re-entrant fold over the folding tool 19 in substantially the same manner as described above with reference to the arrangement of Figures 1 to 5. Similarly, the two fold packets 21 , 22 are again created in a substantially identical manner whereupon the folding tool 19 is withdrawn from the inner chamber 11 in a direction out of the page as viewed in Figure 9, thereby leaving behind the fabric divider 16 in the form of the reentrant fold which extends upwardly from the base region 3 towards the opening 20 of the housing 2.

The arrangement illustrated in Figure 10 represents a further modification of the arrangement described above with reference to Figure 9. In this arrangement, the tool 19 is simply positioned across the top of the housing 2 so as to lie immediately above the upper level of the housing when in its folding position illustrated in Figure 10. Nevertheless, the fabric divider 16 (which in this embodiment is again separate from the air-bag 14) is folded over the tool 19 so as to take the form of a re-entrant fold again extending from the base region 3 of the housing towards the opening 20. The two fold packets 21 , 22 are again created in a similar manner, with the tool 19 in position as illustrated in Figure 10 whereafter the tool 19 can be withdrawn from its position above the housing in a direction out of the page as viewed in Figure 10, leaving behind the re-entrant fold 19. However, it will be appreciated that immediately upon withdrawal of the tool 19 in a direction out of the page as illustrated in Figure 10, the uppermost part of the re-entrant will project a short way out of the opening 20 of the housing 2. This is not a problem, however, and this region of the re-entrant fold can simply be pressed downwardly or otherwise tucked into the housing 2 before the housing 2 is closed by an appropriate cover.

With the tool 19 positioned above the housing 2 as illustrated in Figure 10, it is possible to move the tool a short distance to the left or right as illustrated by arrow G in Figure 10. This small freedom of movement of the tool provides increased flexibility when packaging the air-bag, and in particular when forming the two fold packets 21 , 22. For example, when forming the first fold packet 21 , the tool 19 could be moved to the left of the position illustrated in Figure 10, thereby providing slightly more space within which to package the first fold packet within the right-hand part of the chamber 11. Similarly, as the second fold packet 22 is formed, the tool 19 could be moved to the right of the position illustrated in Figure 10, thereby creating a slightly larger space for the insertion of the second fold packet into the left-hand region of the chamber 11.

In the arrangement of Figure 10, the folding tool 19 preferably takes the form of an elongate rod or bar of circular cross-section although it should be appreciated that other cross-sectional forms are also possible.

Figure 11 illustrates a further variation of the arrangement described above with reference to Figure 10. In this arrangement, the folding tool 19 again takes the form of an elongate rod or bar, preferably of circular cross-section, but rather than being positioned above the housing 2 is instead received in an arcuate recess, preferably in the form of a groove, formed in the top of the housing 2. Of course, it will be appreciated that this arrangement does not facilitate movement of the tool 19 from side to side as in the case of the arrangement of Figure 10.

Figure 12 illustrates an alternative embodiment of the present invention in which the housing 2 is formed of fabric material, and takes the form of a bag which, in the arrangement illustrated in Figure 12, hangs downwardly from a mounting flange 28. The fabric housing 2 again has a base region 3 at the bottom and opening 20 at the top, and is provided with a pair of closure flaps 29 configured to close the opening 20 once an air-bag has been packed into the inner chamber 11 of the housing 2.

The inflator 9 projects through the mounting aperture 8 formed in a side region of the fabric housing 2 such that the outlet region 10 extends into the inner chamber 11 and is directed generally upwardly. Due to the flexible nature of the housing 2 in this embodiment, it is not sufficient for the gas generator 9 to be held in place simply by virtue of its insertion through the mounting aperture 8 and, instead, the inflator 9 would need to be substantially rigidly mounted relative to some other structure of the motor vehicle (not shown) outside the housing 2.

The fabric housing 2 is provided with an aperture 18 generally adjacent and below the inflator 9, for the insertion of a folding tool 19 (similar to that of the embodiment described above with reference to Figures 1 to 5) into the inner chamber 11. Figure 12 illustrates the folding tool 19 in its initial folding position in which a fabric divider 16 can be folded over the tool so as to adopt the form of a re-entrant fold extending generally upwardly from the base region of the housing towards the opening 20.

For the sake of clarity, the air-bag 14 is omitted from Figure 12, but it is illustrated in Figure 13 in its fully packaged state in which it forms a folded package housed within the inner chamber 11 of the housing 2. Two fold packets 21 , 22 are again formed on respective sides of the folding tool 19, whereafter the folding tool 19 can be withdrawn from the aperture 18 in the direction indicated by arrow H, leaving behind the fabric divider 16 in the form of a re-entrant fold separating the two fold packets from one another. It will therefore be appreciated that as in the other embodiments, the fabric divider 16 is thus effectively tucked inwardly of the air-bag package within the housing 2.

Figures 14 and 15 illustrate another embodiment which incorporates a fabric housing 2 of a generally similar form to that of the arrangement shown in Figures 12 and 13. However, in this embodiment, a region of the fabric housing 2 defines the fabric divider separating the two fold packets 21 , 22 from one another. More particularly, as illustrated in Figure 14, a folding tool 19 is again utilised in creation of the fabric divider of this arrangement, the tool 19 being shown in its folding position in Figure 14. The air-bag housing 2 of this arrangement is not provided with any aperture for insertion of the tool 19 but rather, as the tool 19 is moved upwardly, from a position below the air-bag housing so as to adopt the folding position illustrated in Figure 14, the tool creates a re-entrant fold 30 in the fabric housing 2, the re-entrant fold 30 extending upwardly from the base region 3 and into the internal chamber 11.

As illustrated in Figure 15, the folding tool 19 of this arrangement is generally comb-shaped, having a plurality of upwardly-directed fingers 31 which are spaced apart from one another so as to define a series of gaps 32 between neighbouring fingers 31. The fingers 31 are all joined at their lower end by a spine region 33.

In order to ensure that the re-entrant fold formed in the fabric housing 2 by the initial upwards movement of the tool 19 into the position illustrated in Figures 14 and 15, after subsequent withdrawal of the tool, opposed regions of the fold are stitched together by lines of stitching 34 at positions between the fingers 31 of the tool 19. When the opposed regions of the fabric divider defined by the re-entrant fold 30 are stitched together in this manner, the tool 19 can then be withdrawn from the fold in a downwards direction as indicated by arrow I in Figure 15, leaving behind the re-entrant fold 30. The lines of stitching 34 thus serve to prevent the re-entrant fold 30 from unfolding in the absence of the tool 19.

Figure 16 illustrates a variant of the arrangement described above with reference to Figures 14 and 15. In this arrangement, the fabric housing 2 is provided with an aperture 18 for the insertion of the tool 19 and in this arrangement the fabric divider is instead defined by a re-entrant fold 24 formed in part of the air-bag 14 between the fold packets 21 , 22. The air-bag 14 is folded into the folded package illustrated in Figure 16 in a manner largely identical to that described above with reference to Figure 7. However, in this arrangement, the re-entrant fold 24 is stitched (as illustrated at 35 in Figure 16) according to a procedure substantially identical to that described above with reference to the arrangement of Figures 14 and 15. In this arrangement, the tool 19 which has the same form as illustrated in Figure 15, is inserted through the aperture 18 provided in the fabric housing 2 whereafter the re-entrant fold 24 and the fold packages 21 and 23 are created. The stitching 35 is then created as lines extending between the fingers 31 of the tool 19, whereafter the tool 19 is withdrawn in a downwards direction leaving behind the re-entrant fold 24.

Figure 17 illustrates an arrangement which is similar in many respects to that described above with reference to Figure 10. In particular, it can be seen that the folding tool 19 used to produce this arrangement again takes the form of an elongate rod or bar and is initially positioned above the substantially rigid housing 2 of the air-bag module. However, in this arrangement the fabric divider is defined by part of a wrapper or soft cover 36. One end of the cover 36 is folded over the tool 19 and is then laid within the region of the inner chamber 11 which lies on the opposite side of the tool 19 to the inflator 9. The first fold package 21 of the air-bag 14 is then created and packed within the right-hand region of the chamber 11 whereafter the second fold packet 21 can be created and packed into the left-hand region of the chamber 11 , thereby creating the folded air-bag package. The tool 19 can again be moved to the left and/or right as illustrated by arrow J in Figure 17 in order to facilitate easier packaging of the air-bag.

When the air-bag 14 has been packaged as described above, the tool 19 is withdrawn by pulling in a direction out of the page as illustrated in Figure 16, whereafter the region of the fold extending above the housing 2 can be tucked down into the housing. The region of the wrapper or soft cover 36 extending out of the chamber 11 can then be folded back across the chamber and secured in order to retain the packaged air-bag within the housing 2.

Figure 18 illustrates another embodiment of the present invention during production. In this arrangement, the fabric divider is formed as a separate and discrete sheet of fabric 16. However, in contrast to the arrangement described above with reference to Figure 10, in this arrangement, the sheet of fabric 16 is provided within the inner volume 15 of the air-bag 14. Nevertheless, the fabric divider 16 is again folded over the tool 19, whereafter the first and second fold packages 22 are packed into the chamber 11 of the housing 2 after which the tool 19 is withdrawn from the folding position illustrated in Figure 18. This leaves behind the fabric divider, which again is effectively tucked inwardly of the air-bag package so as to extend from the base region 3 of the housing towards the opening 20.

Although the present invention has been described in detail with reference to particular embodiments, it should be appreciated that certain modifications could be made to the arrangements without departing from the scope of the present invention. For example, in arrangements where the fabric divider is formed from a sheet of fabric which is separate from the air-bag and/or housing, then it is possible for the fabric defining the divider to have a lower degree of flexibility than the air-bag and/or housing in order to ensure that the divider properly remains in place during the early stages of inflation and serves its purpose of preventing gas being directed from the inflator 9 directly into the region of the air-bag defining the fold packet which is to be pulled out of the air-bag housing rather than pushed.

It is also envisaged that in certain applications, the fabric defining the divider could be treated so as to increase, or indeed perhaps lower, its coefficient of friction. 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. An air-bag module (1) for a motor vehicle safety device, the module comprising : a housing (2) having a base (3) and an opening (20), and containing an inflatable fabric air-bag (14); and an inflator (9) configured to inflate the air-bag through the opening, wherein the air-bag (14) is provided in the form of an initially folded package comprising a pair of fold packets (21 ,22) characterised in that said fold packets (21 ,22) are separated from one another by a fabric divider (16, 24, 30) tucked inwardly of the air-bag package and extending from the region of base (3) of the housing towards the opening (20).

2. An air-bag module according to claim 1, wherein the fabric divider (16) is separate from the air-bag (14) and from the housing (2)

3. An air-bag module according to claim 2, wherein the fabric dividers (16) is secured relative to the housing (2).

4. An air-bag module according to claim 2 or claim 3, wherein the fabric divider (16) is located outside the air-bag (14), but at least partly within the housing (2).

5. An air-bag module according to claim 2 or claim 3, wherein the fabric divider (16) is formed inside the air-bag (14).

6. An air-bag module according to claim 1 , wherein the fabric divider (24) forms part of the air-bag (14).

7. An air-bag module according to claim 1 , having a housing (2) made from fabric and wherein the fabric divider (30) forms part of the housing (2).

8. An air-bag module according to any preceding claim, wherein the fabric divider (30) is formed in the manner of a re-entrant fold (16,24,30) so as to extend inwardly of the air-bag package.

9. An air-bag module according to claim 8, wherein at least a region of said re-entrant fold (24,30) is stitched (34,35) such that opposed regions of the divider are secured to one another.

10. An air-bag module according to claim 8 as dependent upon claim 4 or claim 6, wherein the housing (2) is provided with an aperture (18) or recess

(27) to receive a tool (19) for insertion into the housing (2), around which tool the re-entrant fold defining the divider is formed.

11. An air-bag module according to claim 10, wherein an aperture (18) is formed through the base region (3) of the housing (2) for the insertion of said tool (19).

12. An air-bag module according to claim 11 , wherein said aperture (19) or recess (27) is formed in the housing substantially adjacent said inflator.

13. An air-bag according to any one of claims 10 to 12 produced by a method incorporating the steps of : inserting a tool (19) into said aperture (18) or recess; creating said re-entrant fold (16,24,30) over said tool and folding the air-bag (14) to create said fold packets (21 ,22); and subsequently removing said tool (14) from the aperture or recess.

14. An air-bag module according to claim 8 as dependent upon claim 7, produced by a method incorporating the steps of : creating said re-entrant fold (30) over a tool (19) and folding the air-bag (14) to create said fold packets (21 ,22); and subsequently removing said tool from the re-entrant fold.

15. An air-bag module according to claim 13 or 14, wherein said tool (19) has a plurality of spaced apart fingers (31) and wherein said method includes the step of stitching (34) together opposed regions of said divider (24,30) at positions between said fingers (31 ), before removal of said tool.