Abstract
An airbag configured to be inflated by a source of gas, the airbag being formed from first and second layers of fabric arranged in superimposition to define an inflatable chamber between the layers for the receipt of inflating gas. Each layer of fabric has a structure (e.g. a weave) comprising at least one yarn, and the two layers are interconnected by at least one tether yarn extending between the layers within the inflatable chamber. The or each tether yarn is implicated in the structure of the first layer at a plurality of first connection regions, and is implicated in the structure of the second layer at a plurality of second connection regions. Each said first connection region is wider in a length-direction of the, or each, tether yarn than each said second connection region, and said second connection regions are offset relative to said first connection regions.
Claims
1. An airbag configured to be inflated by a source of gas, the airbag being formed from first and second layers fabric arranged in superimposition to define an inflatable chamber between the layers for the receipt of inflating gas; each layer of fabric having a structure comprising at least one yarn, and the two layers being interconnected by at least one tether yarn extending between the layers within the inflatable chamber, wherein: the, or each, tether yarn is implicated in the structure of the first layer within a plurality of first connection regions, and is implicated in the structure of the second layer within a plurality of second connection regions, wherein each said first connection region is wider in a length-direction of the, or each, tether yarn than each said second connection region, and wherein said second connection regions are offset relative to said first connection regions such that said second connection regions do not oppose any said first connection regions across the inflatable chamber, the at least one tether yarn thereby serving to induce curvature to the airbag when its inflatable chamber is inflated.
2. The airbag according to claim 1, wherein said first connection regions are spaced apart from one another across at least a portion of said first layer, and said second connection regions are spaced apart from one another across at least an opposing portion of said second layer.
3. The airbag according to claim 2, wherein the position on said second fabric layer of at least one said second connection region is interposed between the positions on said first fabric layer of two adjacent first connection regions.
4. The airbag according to claim 2, wherein no tether yarns extend between any of said second connection regions without being implicated in the structure of the first layer between said second connection regions.
5. The airbag according to claim 2, wherein at least one said first connection region comprises a plurality of spaced-apart connection sub-regions within which the, or each, tether yarn is implicated in the structure of said first layer, and wherein the, or each, tether yarn extends between said connection sub-regions of the, or each, first connection region without being implicated in the structure of either the first layer or the second layer between said connection sub-regions.
6. The airbag according to claim 1, wherein each said layer of fabric is woven and has a weave comprising a plurality of generally parallel woven yarns.
7. The airbag according to claim 6, wherein the, or each, tether yarn is interwoven with yarns of the first layer within each said first connection region, and is interwoven with yarns of the second layer within each said second connection region.
8. The airbag according to claim 7, wherein the, or each, tether yarn is interwoven with yarns of either said layer only within said connection regions.
9. The airbag according to claim 5, each said layer of fabric is woven and has a weave comprising a plurality of generally parallel woven yarns, and wherein the, of each, tether yarn is interwoven with yarns of the first layer only within said connection sub-regions and is interwoven with yarns of the second layer only within said second connection regions.
10. The airbag according to claim 6, wherein said generally parallel woven yarns of each layer of fabric are warp yarns, each layer of fabric further comprising a plurality of generally parallel weft yarns, and wherein the, or each, tether yarn extends generally parallel to said weft yarns.
11. The airbag according to claim 6, wherein said generally parallel woven yarns of each layer of fabric are warp yarns, each layer of fabric further comprising a plurality of generally parallel weft yarns, and wherein the inflatable airbag comprises a plurality of said tether yarns, the tether yarns extending generally parallel to said weft yarns of the fabric layers.
12. The airbag according to claim 11, wherein each said connection region is generally elongate, said first and second connection regions extending generally parallel to one another and across respective fabric layers of the airbag so as to traverse a plurality weft yarns of the fabric layers.
13. The airbag according to claim 12, wherein said first and second connection regions traverse said plurality of weft yarns at an oblique angle to said weft yarns, and traverse said plurality of warp yarns at an oblique angle to said warp yarns.
14. The airbag according to claim 6, wherein the airbag is a one-piece woven airbag comprising at least one integrally woven seam defined by a region in which yarns of the weave of one said layer are interwoven with yarns of the weave of the other said layer.
15. The airbag according to claim 14, wherein the, or each, tether yarn is integrally woven into the weave of said layers within said connection regions.
Description
SUMMARY OF THE FIGURES
[0050] 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:
[0051] FIG. 1 is a perspective view of a section through part of an airbag, showing an internal tether arrangement;
[0052] FIG. 2 is diagrammatic sectional view of a conventional internal tether arrangement provided within an airbag;
[0053] FIG. 3 is a diagrammatic sectional view of another conventional internal tether arrangement within an airbag;
[0054] FIG. 4 is a diagrammatic section view of an internal tether arrangement provided within an airbag in accordance with an aspect of the present invention;
[0055] FIG. 5 is a diagrammatic sectional view showing one way in which a tether yarn may be implicated in the weave of a layer of the airbag;
[0056] FIG. 6 is a diagrammatic sectional view showing another way in which a tether yarn may be implicated in the weave of a layer of the airbag;
[0057] FIG. 7 is a diagrammatic view of an airbag showing a plurality of connection regions where tether yarns are implicated in the weave of a layer of the airbag;
[0058] FIG. 8 is a diagrammatic sectional view similar to that of FIG. 4, but which shows the tether arrangement inducing curvature to the airbag upon inflation;
[0059] FIG. 9 is a cross-sectional view through an inflated airbag, illustrating curvature induced to the airbag upon inflation;
[0060] FIG. 10 is a perspective view of an uninflated airbag in accordance with an aspect of the invention;
[0061] FIG. 11 is another perspective view of the airbag illustrated in FIG. 10, but which shows the airbag in an inflated, and curved, configuration;
[0062] FIG. 12 is a schematic illustration, from the front, of a pair of specific airbags inflated around the hip region of a person to provide protection to the hip region of the person;
[0063] FIG. 13 is a schematic illustration, from below, of the pair of airbags of FIG. 12 inflated around the person's hip region;
[0064] FIG. 14 is a schematic illustration similar to that of FIG. 12, but which shows a pair of specific airbags of alternative configuration to those of FIGS. 12 & 13;
[0065] FIG. 15 is a schematic illustration, from below, of the pair of airbags of FIG. 14 inflated around the person's hip region;
[0066] FIG. 16 is a schematic plan view of a one-piece woven web comprising opposing layers of woven fabric, within which are formed a pair of airbags in accordance with an aspect of the invention;
[0067] FIG. 17 is a plan view from above showing a pair of airbags obtained from the web illustrated in FIG. 16;
[0068] FIG. 18 is a schematic plan view from above showing a single one of the airbags of FIG. 17;
[0069] FIG. 19 is a is a schematic illustration, from the front, which is similar to FIGS. 12 and 14, but which instead shows the airbags of FIG. 17 inflated around the hip region of a person to provide protection to the hip region of the person; and
[0070] FIG. 20 is a is a schematic illustration, from the below, which is similar to FIGS. 13 and 15, but which instead shows the airbags of FIG. 17 inflated around the hip region of a person to provide protection to the hip region of the person.
DETAILED DESCRIPTION OF THE INVENTION
[0071] Aspects and embodiments of the present invention will now be discussed with reference to the accompanying figures. Further aspects and embodiments will be apparent to those skilled in the art.
[0072] Turning initially to consider FIG. 1, there is illustrated a region of an airbag 1 which is configured to be inflated by a source of gas. As will be appreciated, and as is conventional, the airbag 1 is formed from first (upper) and second (lower) layers of fabric 2, 3, each of which is woven from warp yarns 4 and weft yarns 5 and thus has a structure in the form of a weave. It is to be appreciated, however, that the invention may alternatively be applied to an airbag in which the layers of fabric are knitted layers, in which case the layers will have a structure in the form of a knit comprising at least one yarn.
[0073] The two layers of fabric 2, 3 are arranged in superimposition, and are interconnected around their peripheral edges by a peripheral seam 6 (only part of which is shown in FIG. 1), thereby defining an inflatable chamber 7 between the layers 2, 3 for the receipt of inflating gas from an inflator (not shown) such as a gas generator, in a known manner. The airbag 1 may be woven via a so-called one-piece weaving technique, in which the two layers 2, 3 are woven simultaneously, with the yarns 4, 5 of the two layers 2, 3 being interwoven at predetermined regions to form the peripheral seam 6 (and optionally other seams and/or other interconnections not shown in FIG. 1) as an integral structural feature of the airbag 1.
[0074] An exemplary one-piece weaving technique for making an airbag is described in more detail in International Patent Publication WO199009295A.
[0075] The airbag 1 illustrated in FIG. 1 has a known configuration of integrally woven internal tether arrangement. At selected positions throughout the layers 2, 3, additional tether yarns 8 are also woven into the weave of the fabric, as illustrated schematically in FIG. 1 and in more detail in FIG. 2. The tether yarns 8 are woven so as to extend substantially parallel with the weft yarns 5 of the fabric (and thus substantially perpendicular to the warp yarns 4), and pass over and under successive warp yarns 4 within predetermined connection regions 9 so as to be implicated in the weave of the layers 2, 3 at the connection regions 9. The tether yarns 8 may have a different construction to the warp and weft yarns 4, 5 of the fabric layers 2, 3, such as described in European patent publication EP2407353A.
[0076] At the edges of each connection region 9, the tether yarns 8 pass out of the respective fabric layer 2, 3 in which they are woven and extend towards the opposing layer 3, 2. In the particular arrangement illustrated in FIGS. 1 and 2, the tether yarns 8 each extend into the opposing fabric layer 3, 2 and are woven integrally with it at another connection region 9. As will thus be noted from FIG. 2, the tether yarns 8 are arranged to cross one another, passing out of one fabric layer 2, 3 and extending into the other fabric layer 3, 2. The tether yarns 9 thus cooperate to define a tether 10 which serves to interconnect the two fabric layers 2, 3 within and across the inflatable chamber 7 of the airbag 1. As illustrated in FIG. 2, each tether 10 may be defined by a plurality of tether yarns 8; in this case two pairs of crossing tether yarns 8.
[0077] FIG. 3 illustrates a larger expanse of the two fabric layers 2, 3, from which it will be seen that the tether yarns 8 are each implicated in the structure (i.e. in the weave) of the two layers 2, 3 at a plurality of connection regions 9. In the prior art arrangement shown in FIG. 3, each layer 2, 3 has a plurality of spaced-apart connection regions 9 within which the tether yarns are interwoven with the fabric of the respective layer 2, 3. Furthermore, it will be noted that each connection region 9 of the first layer 2 is located opposite a respective connection region 9 of the second layer 3, across the inflatable chamber 7 defined between the two layers 2, 3.
[0078] FIG. 3 illustrates the two fabric layers 2, 3 located generally adjacent one another, as would be the situation in the uninflated condition of the airbag 1. As will be appreciated by those of skill in the art, as the airbag 1 is inflated by the injection of inflating gas into the inflatable chamber 7, the first and second layers 2, 3 of the airbag 1 will begin to move apart such that the airbag will begin to achieve an inflatable configuration. During inflation, the tether yarns 8 will become tensioned, thereby cooperating to resist further movement of the two layers 2, 3 apart from one another as the airbag 1 is inflated, which can serve an important function in controlling the inflated depth or thickness of the airbag 1 in certain airbag installations, such as those involving the use of the airbag 1 in a safety arrangement within a motor vehicle.
[0079] Turning now to consider FIG. 4, there is illustrated a tether arrangement for an airbag 1 in accordance with an embodiment of the present invention, which offers a significant advantage over the conventional arrangement described above and illustrated in particular in FIGS. 2 and 3. As will be apparent to those of skill in the art, the tether arrangement illustrated in FIG. 4 shares several features and similarities with the conventional arrangement shown in FIGS. 2 and 3, which will therefore not be described in detail again. Nevertheless, it is to be noted that the airbag 1 in accordance with the invention may also be formed by a one-piece weaving technique such as that disclosed in International Patent Publication WO199009295A, and may incorporate tether yarns 8 having a different construction to the warp and weft yarns 4, 5 of the airbag's fabric layers 2, 3, such as described in European patent publication EP2407353A.
[0080] As will be observed, in the arrangement illustrated in FIG. 4 the tether yarns 8 do not cross one another as they pass out of the weave of one fabric layer and into the weave of the other fabric layer. In contrast to the conventional arrangement illustrated in FIGS. 2 and 3, the tether yarns 8 instead each follow a substantially similar path through the weave of the two layers 2, 3. In particular, it will be observed that the tether yarns 8 follow a path in which they are each implicated in the weave of the first layer 2 (for example by being interwoven with warps yarns 4 of the first layer 2) within a plurality of first connection regions 9a, and in which they are each implicated in the weave of the second layer 3 (for example by being interwoven with warps yarns 4 of the first layer 2) within a plurality of second connection regions 9b. The tether yarns 8 are interwoven with the yarns of the fabric layers 2, 3 only within the connection regions 9a, 9b. It is envisaged that the warp yarns 8 will be integrally woven into the weave of the two layers of fabric 2, 3, within the connection regions 9a, 9b during the one-piece weaving process by which the fabric layers 2, 3 themselves are simultaneously woven.
[0081] As illustrated in FIG. 4, in the particular arrangement illustrated, each first connection region 9a actually comprises a pair of connection sub-regions 9a which are spaced apart from one another in the weft direction 11 of the first layer of fabric 2. Within each first connection region 9a, it will be observed that the tether yarns 8 are interwoven with the yarns of the first layer of fabric 2 only within the connection sub-regions 9a. The tether yarns 8 thus pass between the connection sub-regions 9a within each first connection region 9a without being implicated in the weave structure of the first layer 2 (or indeed the second layer 3). Between the connection sub-regions 9a, the tether yarns 8 simply pass adjacent the first fabric layer 2, within the inflatable chamber 7 of the airbag. It is to be appreciated, however, that in other embodiments, the tether yarns 8 may be interwoven with the yarns of the first layer of fabric 2 throughout the width (in the weft direction 11) of each first connection region 9a, in which case there will be no discrete sub-regions 9a as described above.
[0082] The first connection regions 9a themselves are also spaced apart from one another in the weft direction 11 of the first layer of fabric 2, and indeed the second connection regions 9b are also spaced apart from one another in the weft direction 11 of the second layer of fabric 3. Significantly, it will be observed that the tether yarns 8 are implicated in the weave of the layers of fabric 2, 3 in an arrangement in which each first connection region 9a is wider in a length-direction of the tether yarns 8 (i.e. corresponding to the weft direction 11 in this embodiment) than each of the second connection regions 9b. It will also be observed that there is a greater number of connection sub-regions 9a (i.e. where the tether yarns 8 are actually implicated in the weave of the first layer 2) than second connection regions 9b (i.e. where the tether yarns 8 are implicated in the weave of the second layer 3). Furthermore, it will be observed that the first connection regions 9a and the second connection regions 9b are offset relative to one another in the weft direction 11 of the fabric layers 2, 3, such that the first connection regions 9a of the first layer of fabric 2 do not oppose any of the second connection regions 9b of the second layer of fabric 3 across the inflatable chamber 7, and vice-versa. The arrangement is such that the second connection regions 9b are each interposed between two adjacent first connection regions 9a, in the weft direction 11.
[0083] FIG. 5 illustrates one way in which the tether yarns 8 may each be implicated in the weave of either fabric layer 2, 3. For convenience, FIG. 5 illustrates a single tether yarn implicated 8 in the weave of the first fabric layer 2 within a sub-region 9a of a first connection region 9a, but it is to be appreciated that the tether yarn 8 may be implicated in the weave of the second fabric layer 3 within a second connection region 9b in substantially the same manner. As will be observed, the tether yarn 8 passes between two adjacent warp yarns 4 of the first fabric layer 2 from within the inflatable chamber 7 of the airbag, and is then interwoven between adjacent warp yarns 4 of the fabric layer 2 in a plain weave (i.e. passes over/under every other warp yarn 4) within the sub-region 9a, before passing out of the fabric layer 2 on the side of the inflatable chamber 7 (and then extending towards a neighbouring sub-region 9a, or towards the second fabric layer 3, which is not shown in FIG. 5). The sub-region 9a illustrated in FIG. 5 comprises a group of five adjacent warp yarns 4 with which the tether yarn 8 is interwoven. In other configurations, it is envisaged that the sub-regions 9a, or the second connection regions 9b may comprise more or fewer warp yarns 4, for example three, seven, nine, eleven, thirteen, or indeed any convenient odd number, such that the tether yarn 8 will enter and exit the sub-region 9a or second connection region 9b from the side of the inflatable chamber 7. In arrangements in which the tether yarns 8 are interwoven with the yarns of the first layer of fabric 2 throughout the width (in the weft direction 11) of a first connection region 9a, it is proposed that the first connection region 9a may comprise more than five adjacent warp yarns 4, for example seven, nine, eleven, thirteen, or indeed any convenient odd number.
[0084] FIG. 6 illustrates another way in which the tether yarns 8 may each be implicated in the weave of either fabric layer 2, 3. For convenience, FIG. 6 illustrates a single tether yarn implicated 8 in the weave of the first fabric layer 2 within a first connection region 9a, but it is to be appreciated that the tether yarn 8 may be implicated in the weave of the second fabric layer 3 within a second connection region 9b in substantially the same manner. In this arrangement, the first connection region 9a comprises a first portion 9a.sub.1, a second portion 9a.sub.2 and a third portion 9a.sub.3. Each portion 9a.sub.1-3 of the connection region 9a comprises a respective number of warp yarns 4 of the fabric layer 2 and an arrangement in which the tether yarn 8 passes between or over the warp yarns 4.
[0085] In the first portion 9a.sub.1 of the connection region 9a, the tether yarn 8 passes between two adjacent warp yarns 4a, 4b from the inwardly directed side of the fabric layer 2 defining the inflatable chamber 7 to the outer side of the fabric layer 2, and then partly around two adjacent warp yarns 4b, 4c. When the tether yarn 8 passes partly around two or more adjacent warp yarns in this manner, the tether is said to float over the adjacent warp yarns 6. In other configurations, the tether yarn 8 may float over more than two adjacent warp yarns 4 in the first portion 9a.sub.1 of the connection region 9a. For example, the tether yarn 8 may float over three adjacent warp yarns 4 in the first portion 9a.sub.1 of the connection region 9a.
[0086] In the second portion 9a.sub.2 of the connection region 9a, the tether yarn 8 passes between two warp yarns 4c, 4d from the outer side of the fabric layer 2 to the inwardly directed side, and the tether yarn 8 is interwoven with a predetermined number of single adjacent warp yarns 4d-4j in a plain weave. In the arrangement illustrated in FIG. 6, the tether yarn 8 is interwoven with seven adjacent single warp yarns 4d-4j within the second portion 9a.sub.2 of the connection region 9a such that the tether yarn 8 passes at least partly around three warp yarns 4e, 4g and 4i on the outer side of the fabric layer 2. However, in other arrangements the tether yarn 8 may be interwoven with more than seven single adjacent warp yarns 4. For example, the tether yarn 8 may be interwoven with nine, or eleven, or thirteen single adjacent warp yarns 4 in the second portion 9a.sub.2 of the connection region 9a.
[0087] In the third portion 9a.sub.3 of the connection region 9a, the tether yarn 8 passes between two adjacent warp yarns 4j, 4k from the inwardly directed side of the fabric layer 2 to the outer side of the fabric layer 2, and then floats over two adjacent warp yarns 4k, 4l on the outer side of the fabric layer 2. The tether yarn 8 then passes between a further two adjacent warp yarns 4l, 4m, and back into the inflatable chamber 7 of the airbag 1. In other configurations, the tether yarn 8 may float over more than two adjacent warp yarns 4 in the third portion 9a.sub.3 of the connection region 9a. For example, the tether yarn 8 may float over three adjacent warp yarns 4 in the third portion 9a.sub.3 of the connection region 9a.
[0088] In the arrangements described above with reference to FIG. 6, the tether yarn 8 floats over at least two adjacent warp yarns 4 in the first and third portions 9a.sub.1, 9a.sub.3 of the connection region 9a, and is interwoven with single adjacent warp yarns 4d-4j in the second portion 9a.sub.2 of the connection region 9a. Floating the tether yarn 8 over at least two adjacent warp yarns on one side of the fabric layer 2 in the first and third portions 9a.sub.2, 9a.sub.3 of the connection region 9a allows some movement between the tether yarn 8 and the inherent yarns 4, 5 of the fabric layer 2, which absorbs some of the shock load when the air-bag 1 is inflated. This can help to reduce the likelihood of the tether yarn 8 snapping as the airbag 1 is inflated.
[0089] In arrangements in which the tether yarns 8 are implicated in the weave of both fabric layers 2, 3 in the manner shown in FIG. 6, it is envisaged that the first connection regions 9a may be configured such that the tether yarn 8 is interwoven with a greater number adjacent warp yarns 4 within the second portion 9a.sub.2 of each first connection region 9a than within the equivalent second portion of each second connection region 9b. In this way, the tether yarns 8 may be implicated in the weave of the first layer of fabric 2 throughout each first connection region 9a, such that the first connection regions 9a are wider in the weft direction 11 than the second connection regions 9b within which the tether yarns are implicated in the weave of the second layer 3. Alternatively, it is envisaged that each first connection region 9a may have the configuration shown in FIG. 6, whilst each second connection region 9b may have the (shorter) configuration shown in FIG. 5.
[0090] For the sake of convenience and clarity, FIG. 4 illustrates only two exemplary tether yarns 8, whilst FIGS. 5 and 6 each illustrate only single exemplary tether yarns 8. However, it is to be appreciated than in practical embodiments there may be significantly more tether yarns 8 arranged in a side-by-side relationship to one another, the tether yarns 8 being distributed amongst the weft yarns 5 of the two fabric layers 2, 3, so as to extend generally parallel to the weft yarns 5 and perpendicular to the warp yarns 4, and thereby collectively defining a tether having a width which extends some distance along the warp-direction of the fabric (i.e. into the page as FIGS. 4-6 are viewed). Indeed, in some embodiments it is envisaged that the tether yarns 8 may be provided within a third layer of fabric woven from a third set of warp yarns and the tether yarns 8, wherein the tether yarns 8 define weft yarns of the third layer of fabric. Alternatively, the tether yarns 8 may be provided within a third layer of fabric woven in a manner such that the tether yarns 8 define warp yarns of the third layer.
[0091] FIG. 7 schematically illustrates a region of the airbag 1 as viewed from above, with the first (upper) layer of fabric 2 superimposed on top of the second (lower) layer of fabric 3. The warp yarns 4 of the two layers 2, 3 are substantially aligned with the direction indicated by arrow 12, and weft yarns 5 are substantially aligned with the direction indicated by arrow 11. A plurality of generally parallel tether yarns 8 are provided amongst the weft yarns. The warp yarns are implicated in the weave of the upper layer 2 in a plurality of first connection regions 9a (only one complete first connection 9a being shown) which are spaced apart in the weft direction 11 of the fabric layers 2, 3, and each of which comprises a pair of connection sub-regions 9a The tether yarns 8 are also implicated in the weave of the lower layer 3 in a plurality of second connection regions 9b in the manner described above, although within the extent of the region of the airbag 1 illustrated in FIG. 7 only a single second connection 9b is shown. As will be observed, each connection sub-region 9a and each second connection region 9b is elongate so as to have a length in the warp direction 12. Each connection region 9a, 9b thus extends across a region of its respective layer of fabric 2, 3 so as to traverse a plurality of weft yarns. As will therefore be appreciated, the tether yarns 8 cooperate to define a tether 10 which has a width w in the warp direction 12 of the fabric layers 2, 3.
[0092] In the arrangement of FIG. 7, the tether yarns 8 are all interwoven with the same warp yarns 4 running through the two fabric layers 2, 3, such that the sub-regions 9a of the first connection regions 9a, and the second connection regions 9b are all parallel to one another and oriented such that their length direction is substantially parallel to the warp direction 12 and perpendicular to the weft direction 11. However, this is not essential, and indeed in some circumstances it can be beneficial to arrange the tether yarns 8 such that successive tether yarns 8 are implicated in the weave of the fabric layers 2, 3 by being interwoven with different groups of warp yarns 4 to one another. As will be appreciated by those of skill in the art, the effect of this can be to orientate the connection regions 9a, 9b so that their elongate extension traverses a plurality of weft yarns 5 at an oblique angle to the weft yarns, and also thus at an oblique angle to the warp yarns 4.
[0093] FIG. 8 is a view generally similar to that of FIG. 4, but which shows the airbag 1 in a partially inflated condition in which an initial volume of inflating gas has been directed into the inflatable chamber 7 of the airbag 1 so as to begin inducing curvature to the airbag. FIG. 9 is a perspective view showing a transverse cross section through an airbag 1 having a tether configuration of the type shown in FIGS. 4 and 8, but which shows the airbag 1 in a substantially fully inflated condition. FIG. 9 shows more clearly the width of the internal tether 10 which is defined by the tether yarns 8. As will be appreciated from both figures, the inflating gas urges the two fabric layers 2, 3 apart from one another, such that the airbag 1 achieves a degree of inflated depth across the inflatable chamber. Movement of the fabric layers 2, 3 apart from one another is restrained by the tether yarns 8 running through the airbag 1. As will be appreciated, the tether yarns 8 are placed under tension in this condition, and subjected to strain. Because of the above-described configuration of the first and second connection regions 9a, 9b where the tether yarns 8 are implicated in the weave of the first and second fabric layers 2, 3 respectively, with the first connection regions 9a in the first fabric layer 2 having a greater width in the length-direction of the tether yarns 8 than second connection regions 9b in the second fabric layer 3, the first and second connection regions 9a, 9b are subjected to different levels of strain to one another. It has been found that the effect of this is to induce curvature to the airbag 1 when it is inflated, as illustrated in FIG. 8 and particularly in FIG. 9. As will be observed, the above-described tether configuration is effective to induce curvature to the airbag 1, the curvature being convex on the side of the first fabric layer 2 (the layer with wider tether connection regions 9a), and concave on the side of the second fabric layer 3 (the layer with narrower tether connection regions 9b). The airbag 1 is thus configured to bend towards the second fabric layer 3 upon inflation. As will be appreciated, the airbag 1 bends about the longitudinal extension direction of the first and second connection regions 9a, 9b.
[0094] FIG. 10 illustrates a one-piece woven airbag 1 in accordance with the invention, in a pre-inflated configuration in which it is laid flat. The airbag 1 has a somewhat elongate configuration, and is shown with its second fabric layer 3 (the layer with the narrower second connection regions 9b) presented upwardly. The integral peripheral seam 6 of the illustrated airbag 1 follows a circuitous path having a re-entrant region such that the resulting inflatable chamber 7 of the airbag has a shape resembling a pair of spectacles, presenting two major chamber regions 7a, 7b which are fluidly interconnected by a narrower region 7c. Adjacent the re-entrant region of the peripheral seam 6, outside the inflatable chamber 7, the yarns of the two fabric layers 2, 3 are interwoven to define a non-inflatable region 13 of the airbag, in the manner of a thicker web of fabric.
[0095] The second connection regions 9b within which the tether yarns 8 are implicated in the weave of the second fabric layer 3 are also clearly visible in FIG. 10. As will be observed, a first group of the second connection regions 9b is provided in a region of the fabric layer 3 defining the first chamber region 7a, and a second group of the second connection regions 9b is provided in a region of the fabric layer 3 defining the second chamber region 7b. Although not visible in FIG. 10, first connection regions 9a within which the tether yarns 8 are implicated in the weave of the underlying first fabric layer 2 are also provided. Like the second connection regions 9b, the first connection regions 9a are similarly split into two groupsnamely a first group provided in a region of the underlying first fabric layer 2 defining the first chamber region 7a, and a second group provided in a region of the underlying first fabric layer 2 defining the second chamber region 7b. The connection regions 9a, 9b in the first group (i.e. corresponding to the first chamber region 7a) are arranged to as to extend parallel to one another, whilst the connection regions 9a, 9b in the second group (i.e. corresponding to the second chamber region 7b) are also arranged to as to extend parallel to one another. However, it will be observed that the connection regions 9a, 9b of the first group are not parallel to the connection regions 9a, 9b of the second group. Turning now to consider FIG. 11, the airbag 1 of FIG. 10 is illustrated in an inflated condition. As will be noted, the tether yarns 8 forming the first and second connection regions 9a, 9b of the first group (i.e. corresponding to the first chamber region 7a) serve to induce a first curvature to the first chamber region 7a of the airbag 1 such that it bends upwardly. Similarly, the tether yarns 8 forming the first and second connection regions 9a, 9b of the second group (i.e. corresponding to the second chamber region 7b) serve to induce a second curvature to the second chamber region 7b of the airbag 1 such that it also bends upwardly. As will be appreciated, the first chamber region 7a is thus caused to achieve an inflated shape in which it bends about the longitudinal extension direction of the first group of connection regions 9a, 9b, and the second chamber region 7a is thus caused to achieve an inflated shape in which it bends about the longitudinal extension direction of the second group of connection regions 9a, 9b. As will be noted, in this arrangement each chamber region 7a, 7b is thus configured to bend in a single direction, with the two directions being different to one another and defined by the direction of extension of the connection regions 9a, 9b across the local regions of the fabric layers 2, 3.
[0096] FIGS. 12 and 13 illustrate a practical embodiment of airbags 1 configured to bend in a single direction in the manner described above. The illustrated arrangement comprises a pair of hip-protection airbags 1 arranged and configured to provide hip protection to a person 14 in a sitting position. As shown in FIG. 12, each airbag 1 is provided with a respective inflator such as a gas generator 15 to direct a volume of inflating gas into the internal chamber 7 of the airbag 1. It is envisaged that the airbags 1 may be provided within a garment or the like configured to be worn by the person 14. The airbags 1 are arranged to inflate into respective deployed positions around a respective hip area of the person.
[0097] The airbags 1 of FIGS. 12 and 13 are configured so as to be optimised to provide good bending characteristics around the user's sagittal axis (indicated at 16 in FIG. 13) so that the airbags 1 each extend underneath the user's hips. This may be achieved by orientating the connection regions 9a, 9b (within which the tether yarns 8 are implicated in the constituent fabric layers 2, 3 of the airbags) so that they extend generally or approximately parallel to the user's transverse plane (indicated at 17 in FIG. 12). However, because the airbags 1 are configured to bend only around the user's sagittal axis 16, they are less well suited to bend around the sides of the user's hips, which results in the airbags 1 achieving respective inflated configurations in which they can flare outwardly from the user's rear hip area and away from the user's upper legs, leaving a gap 18 between the user's legs and each airbag 1.
[0098] FIGS. 14 and 15 illustrate an alternative configuration of the hip protection airbags 1 shown in FIGS. 12 and 13, which are also configured to bend in a single direction in the manner described above. In this arrangement, however, the airbags 1 are configured so as to be optimised to provide good bending characteristics around the user's vertical axis (indicated at 19 in FIG. 14) so that the airbags better extend around the sides of the user's hips upon deployment, thereby addressing the potential shortcoming of the airbags 1 illustrated in FIGS. 12 and 13. This may be achieved by orientating the connection regions 9a, 9b (within which the tether yarns 8 are implicated in the constituent fabric layers 2, 3 of the airbags) so that they extend generally or approximately parallel to the user's sagittal plane (indicated at 20 in FIG. 12). However, because the airbags 1 are configured to bend only around the user's vertical axis 19, they are now less well suited to bend under the user's hips, which results in the airbags 1 achieving respective inflated configurations in which they provide less effective coverage underneath the user's hips than the airbags of FIGS. 12 and 13, as can be seen by comparing FIG. 15 with FIG. 13.
[0099] In some circumstances, it can therefore be desirable to provide an airbag which can be optimised to bend in two directions rather than merely one direction.
[0100] FIG. 16 illustrates a short length of one-piece woven production web 21 comprising opposing first and second layers of fabric 2, 3. The production web 21 is woven via a one-piece weaving technique such that the two layers of fabric 2, 3 are woven simultaneously on a single specially-configured loom, in a manner known per se. The warp yarns 4 of the fabric extend in the warp direction 12, and the weft yarns 5 of the fabric extend in the weft direction 11. The short length of web 21 illustrated in FIG. 16 can be seen to comprise a pair of integrally formed hip protection airbags 1, the two airbags 1 being formed within the web as mirror images of one another across the longitudinal (i.e. aligned with the warp direction 12) axis 22. The airbags 1 are defined by respective peripheral seams 6 within which the yarns of the two layers of fabric 2, 3 are interwoven such that each peripheral seam 6 is formed as an integral structural feature of the fabric of the respective airbag 1.
[0101] The peripheral seam 6 of each airbag 1 defines the airbag's main inflatable region, but also an elongate inlet region 23 which will be understood to be configured to receive an inflator. In the arrangement illustrated in FIG. 16 it will also be observed that each airbag 1 has an additional integrally formed seam 24 which is substantially linear and which extends inwardly from the peripheral seam 6. As will be explained in more detail hereinafter, the additional seam 24 of each airbag represents a flexure seam and is provided to help induce curvature to the airbag 1 when it is inflated.
[0102] Each of the airbags 1 may be removed from the production web 21 by cutting through the fabric layers 2, 3 of the web, around the peripheral seam 6. The resulting airbags 1 are illustrated after removal from the production web 21 in FIG. 17, in which it will be noted that the airbags 1 are shown in different orientations to FIG. 16.
[0103] As in the previous embodiments, the airbags 1 shown in FIGS. 16 and 17 are also provided with internal tether arrangements of the same general configuration as described previously, and thus comprise a plurality of tether yarns 8 which are implicated in the weave of the first fabric layer 2 at first connection regions 9a (each of which comprises a pair of connection sub-regions 9a), and which are implicated in the weave of the second fabric layer 3 at second connection regions 9b. The first and second connection regions 9a, 9b are all elongate, and are arranged so as to extend at oblique angles to both the warp direction 12 and the weft direction 11. The connection regions 9a, 9b thus extend at oblique angles to the warp yarns 4 and the weft yarns 5 of the fabric layers 2, 3. As will be understood from the foregoing description of previous embodiments, the tether yarns 8 are provided amongst the weft yarns 5 and thus follow the weft direction 11. The tether yarns 8 are interwoven with warp yarns 4 of the first fabric layer 2 within the first connection regions 9a, and are interwoven with warp yarns 4 of the second fabric layer 3 within the second connection regions 9b.
[0104] The particular arrangement of the connection regions 9a, 9b in this embodiment may be most clearly understood having regard to FIG. 18, in which the sub-regions 9a of the first connection regions 9a (within which tether yarns 8 are implicated in the weave of the first fabric layer 2) are illustrated in solid lines, and the second connection regions 9b (within which tether yarns 8 are implicated in the weave of the second fabric layer 3) are indicated in dashed lines.
[0105] In particular, it will be observed in FIG. 18 that the connection regions 9a, 9b are provided in two discrete groups of connection regions, namely a first group positioned within the first notional rectangular region 25, and a second (larger) group positioned within the second notional rectangular region 26. The two groups 25, 26 are located adjacent one another, and as will be appreciated, each group 25, 26 of connection regions comprises both first connection regions 9a (within which tether yarns 8 are implicated in the weave of the first fabric layer 2) and second connection regions 9b (within which tether yarns are implicated in the weave of the second layer 3.
[0106] As will be observed, the connection regions 9a, 9b within the first group 25 are all substantially parallel to one another, whilst the connection regions 9a, 9b within the second group 26 are also substantially parallel to one another. However, the connection regions 9a, 9b of the first group 25 are non-parallel to the connection regions 9a, 9b of the second group 26. The connection regions 9a, 9b of the first group 25 thus extend at an oblique angle to the extension of the connection regions 9a, 9b of the second group 26.
[0107] A significant difference between the configuration of the airbags 1 illustrated in FIGS. 16 to 18 and the previous embodiment illustrated in FIGS. 10 and 11 (which also has two discrete groups of connection regions 9a, 9b) concerns the relationship between the connection regions 9a, 9b of the first group 25 and the connection regions 9a, 9b of the second group 26.
[0108] In the configuration of FIGS. 16 to 18 it will be noted that at least some of the sub-regions 9a of the first connection regions 9a, and the second connection regions 9b of the second group 26 extend across the axes of extension 27 along which the sub-regions 9a of the first connection regions 9a, and the second connection regions 9b of the first group 25 extend. As will be appreciated in light of the preceding description, the tether yarns forming the first group 25 of connection regions 9a, 9b will serve induce a first curvature to the airbag 1 upon inflation, to bend the airbag 1 about the longitudinal extension direction of the first group of connection regions 9a, 9b (i.e. about the extension axes 27). As will therefore be observed, the second group 26 of connection regions 9a, 9b thus traverse the axes 27 about which the first group of connection regions will induce curvature to the airbag 1. This places the second group 26 of connection regions 9a, 9b within a region of the airbag 1 in which curvature is induced by the first group of connection regions 9a, 9b. Furthermore, the tether yarns forming the second group 26 of connection regions 9a, 9b will serve induce a second curvature to the airbag 1 upon inflation, to bend the airbag 1 about the longitudinal extension direction of the second group of connection regions 9a, 9b. Given that the second group 26 of connection regions 9a, 9b are non-parallel to the first group 25 of connection regions 9a, 9b, it will be appreciated that the second curvature will be in a different direction or sense to the first curvature. Because the second group 26 of connection regions 9a, 9b traverse the axes 27 about which the first group 25 of connection regions 9a, 9b induce the first curvature to the airbag 1, the effect is therefore to induce two differently directed curvatures to the same region of the airbag 1, thereby effectively bending the airbag in two different directions.
[0109] Having particular regard to the second group 26 of connection regions 9a, 9b, it will be noted from FIG. 18 that the second group 26 is divided into two sets of connection regions 9a, 9b, namely a first set 28 located on one side of the flexure seam 24, and a second set 29 located on the opposite side of the flexure seam 24. The flexure seam 24 thus separates the two sets 28, 29 of connection regions 9a, 9b within the second group. Furthermore, it will be noted that the flexure seam 24 extends generally orthogonal to the extension of the connection regions 9a, 9b within the second group 26. As will also be observed, each sub-region 9a of the first connection regions 9a of the first set 28 is aligned with a respective sub-region 9a of the second set 29 so that each pair of aligned connection sub-regions 9a extend collinearly. Similarly, each second connection 9b of the first set 28 is aligned with a respective second connection region 9b of the second set 29 so that each pair of aligned second connection regions 9b extend collinearly.
[0110] Noting that the flexure seam 24 interconnects the two layers of fabric 2, 3 of the airbag 1, it will be understood that the flexure seam 24 therefore serves to restrict the inflated depth of the inflatable chamber 7 between the two sets 28, 29 of connection regions 9a, 9b within the second group 26. In this way, the flexure seam 24 can help to permit the second group 26 of connection regions 9a, 9b to induce the second curvature to the airbag 1, the flexure seam 24 effectively defining a crease about which the second group 26 of connection regions 9a, 9b can then more easily bend the airbag 1.
[0111] FIGS. 19 and 20 illustrate a pair of airbags 1 of the configuration described above with reference to FIGS. 16 to 18, showing the airbags 1 in an inflated condition to provide improved hip protection to a person 14 in a sitting position. Both airbags 1 are arranged such that their first fabric layers 2 are directed outwardly, and their second fabric layers 3 are directed inwardly, towards the user 14.
[0112] As will be appreciated, the airbags 1 shown in FIGS. 19 and 20 are optimised to provide good bending characteristics in two different directions, namely around the user's sagittal axis 16 so that the airbags 1 extend underneath the user's hips, and around the user's vertical axis 19 so that the airbags 1 extend around the sides of the user's hips.
[0113] The first group 25 of connection regions 9a, 9b are positioned within an upper region of the airbag 1, and are orientated such that they extend generally or approximately parallel to the user's sagittal plane 16. The connection regions of the first group 25 are therefore configured to induce the first curvature to the airbagbending the airbag 1 around the user's vertical axis 19 so that the airbags 1 extend tightly around the sides of the user's hips instead of flaring outwardly as was observed in the single-bend arrangement of FIGS. 12 and 13.
[0114] The second group 26 of connection regions 9a, 9b are positioned within a lower region of the airbag 1, and are orientated such that they extend generally or approximately parallel to the user's transverse plane 17. The connection regions of the second group 25 are therefore configured to induce the second curvature to the airbagbending the airbag 1 around the user's sagittal axis 16 so that the airbags 1 also extend underneath the user's hips, thereby providing improved coverage underneath the user's hips compared to the single-bend arrangement of FIGS. 14 and 15. The features disclosed in the foregoing description, or in the following claims, or in 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 obtaining the disclosed results, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.
[0115] While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the scope of the invention.
[0116] For the avoidance of any doubt, any theoretical explanations provided herein are provided for the purposes of improving the understanding of a reader. The inventors do not wish to be bound by any of these theoretical explanations.
[0117] Any section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.
[0118] Throughout this specification, including the claims which follow, unless the context requires otherwise, the words have, comprise, and include, and variations such as having, comprises, comprising, and including will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.
[0119] It must be noted that, as used in the specification and the appended claims, the singular forms a, an, and the include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from about one particular value, and/or to about another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by the use of the antecedent about, it will be understood that the particular value forms another embodiment. The term about in relation to a numerical value is optional and means, for example, +/10%.
[0120] The words preferred and preferably are used herein refer to embodiments of the invention that may provide certain benefits under some circumstances. It is to be appreciated, however, that other embodiments may also be preferred under the same or different circumstances. The recitation of one or more preferred embodiments therefore does not mean or imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the disclosure, or from the scope of the claims.
