Inflatable airbag

Abstract

An inflatable airbag (10) for a motor vehicle is disclosed. The airbag (10) comprises fabric layers (11, 12) interconnected by a peripheral seam (13) that extends around and defines a boundary (14) of a single inflatable chamber (15) between the layers (11, 12). The inflatable chamber (15) has an inlet region (20) with a fluid inlet (19) connected to an inflator (27). The first and second circumferentially spaced regions (22, 23) of the peripheral seam (13) are secured together such that the inlet region (20) overlaps with at least one other region (21) of the inflatable chamber (15), thereby creating an inflated shape for the chamber (15) upon inflation of the airbag (10) by gas flow from the inflator (27), the inflated shape being characterized by at least one other region (21) of the inflatable chamber (15) being located adjacent the inflator (27) upon inflation of the airbag (10).

Description

[Technical Field]

[0001] The present invention relates to inflatable airbags, and more particularly to inflatable airbags for automotive safety devices. [Background technology]

[0002] It is now very common to provide airbags in automobiles to protect the vehicle's occupants in the event of an accident, and more recently, to provide airbags configured to inflate over an area outside the vehicle to protect pedestrians if they become trapped by the vehicle. Airbags of all types have been considerably refined over the years, and many now have specific, somewhat complex shapes determined by their particular function, their required inflation characteristics, and the shape and configuration of the portion of the vehicle in which they are mounted or intended to inflate. Such airbags were originally provided in the form of tightly folded and / or rolled packages mounted in airbag modules installed in automobiles.

[0003] Traditionally, airbags are manufactured from woven fabrics and typically comprise two or more fabric layers interconnected by a seam. Often, the fabric layers are woven separately and then sewn together to provide a sewn seam, but in some cases, the layers may be adhesively bonded to one another to form a bonded seam or heat-sealed together to form a fused seam. In some cases, however, the two fabric layers may be woven simultaneously by a so-called one-piece weaving technique, in which the yarns of one fabric layer interweave with the yarns of the other fabric layer in some areas, thereby creating woven seams in those areas that are integrated into the weave of the airbag fabric.

[0004] Airbags generally have an inlet, which is typically directly connected to an inflator, such as a gas generator, allowing inflation gas from the inflator to flow in and inflate the airbag. Such inflators are configured to generate a large, forceful flow of inflation gas, and therefore the force applied to the area of ​​the airbag where the inlet is located can be extremely large. In some situations, this can make it difficult to achieve the desired inflation characteristics of the airbag when there are limitations on the possible location of the inflator. Furthermore, if the inflator must be located in close proximity to the occupant, it can pose a risk of injury to the vehicle occupant, for example, from impact with the inflator during a collision. The inflator can also become very hot during activation, potentially posing a risk of burns to occupants in close proximity to the inflator. Thus, in some airbag installations, it can be difficult to properly position the inflator to ensure the correct inflation characteristics while ensuring that vehicle occupants in close proximity to the inflator are adequately protected from the risk of injury resulting from contact or impact with the inflator.

[0005] The present invention has been devised in consideration of the above. Summary of the Invention

[0006] According to a first aspect of the present invention, there is provided an inflatable airbag for a motor vehicle, the airbag comprising a pair of overlapping fabric layers interconnected by a circumferential seam extending around and defining a boundary of a single inflatable chamber therebetween, the inflatable chamber having an inlet region with a fluid inlet connected to an inflator, the airbag having first and second circumferentially spaced regions of the circumferential seam secured to one another such that the inlet region overlaps at least one other region of the inflatable chamber to thereby cause the chamber to assume an inflated shape upon inflation of the airbag by a flow of gas from the inflator, the inflated shape being characterized by the at least one other region of the inflatable chamber being located adjacent the inflator upon inflation of the airbag.

[0007] Optionally, said inflated shape is further characterized by said at least one other region of the inflatable chamber abutting said inflator upon inflation of the airbag.

[0008] In some embodiments, the expanded shape optionally has a two-tiered configuration in which the inlet region abuts at least one of the other regions.

[0009] Advantageously, the pair of overlapping fabric layers comprises an upper fabric layer and a lower fabric layer, and the inlet region of the inflatable chamber is overlapped with the or each other region such that when the airbag is inflated, the lower fabric layer of the inlet region abuts the upper fabric layer of the or each other region.

[0010] Optionally, the first and second regions of the peripheral seam are secured to one another such that the inlet region of the inflatable chamber overlaps two other separate regions of the inflatable chamber.

[0011] The inlet region of the inflatable chamber may overlap the first and second regions of the peripheral seam.

[0012] According to a second aspect of the present invention, there is provided an inflatable airbag for a motor vehicle, the airbag comprising a pair of superimposed fabric layers interconnected by a peripheral seam extending around and defining a boundary of a single inflatable chamber therebetween, the airbag being characterized in that first and second peripherally spaced regions of the peripheral seam are secured to one another, thereby causing the peripheral seam to follow a non-planar path and impart a three-dimensional inflated shape to the chamber upon inflation of the airbag.

[0013] In some embodiments of the second aspect of the invention, the first and second regions of the peripheral seam are secured in spaced relation to one another such that the first region of the inflatable chamber overlaps at least one other region of the inflatable chamber, thereby providing at least a portion of the inflatable chamber with a two-stage inflation configuration upon inflation of the airbag.

[0014] Optionally, said first region of the inflatable chamber overlies said first and second regions of the peripheral seam.

[0015] Conveniently, the first region of the inflatable chamber may define an inlet to the inflatable chamber, the inlet configured to engage an inflator.

[0016] In some embodiments of the second aspect of the invention, the pair of overlapping fabric layers comprises an upper fabric layer and a lower fabric layer, and the first region of the inflatable chamber is overlapped with the or each other region such that the lower fabric layer of the first region abuts the upper fabric layer of the or each other region when the airbag is inflated.

[0017] Optionally, the first and second regions of the peripheral seam are secured to one another such that the first region of the inflatable chamber overlaps two other separate regions of the inflatable chamber.

[0018] In embodiments of either the first or second aspect of the invention having two separate regions of the inflatable chamber, these regions may be of substantially the same shape and configuration.

[0019] In some embodiments of both aspects of the invention, the first region of the peripheral seam bounds a portion of the other separate region of one of the inflatable chambers, and the second region of the peripheral seam bounds a portion of the other separate region of the other of the inflatable chambers, and the two other separate regions of the inflatable chambers are interconnected by connecting the first and second regions of the peripheral seam to each other.

[0020] Optionally, the two separate other regions of the inflatable chamber are between a first region and a second region of a peripheral seam. Connection of The connecting portion may be substantially mirror symmetrical with respect to the connecting portion.

[0021] Embodiments according to both the first and second aspects of the invention may be configured such that the peripheral seam has an interconnect width across which the fabric layers are interconnected, and the first and second regions of the peripheral seam are secured to one another by a connection formed entirely within the interconnect width.

[0022] Optionally, the interconnect width varies along the peripheral seam, being larger in the first and second regions of the peripheral seam than elsewhere along the seam. Alternatively, the interconnect width varies along the peripheral seam, being smaller in the first and second regions of the peripheral seam than elsewhere along the seam.

[0023] The connection may include stitching. Alternatively or additionally, the connection may include an adhesive or may be formed by fusing the first and second regions of the peripheral seam together with heat. Alternatively or additionally, the connection may comprise one or more rivets or other mechanical fasteners to secure the first and second regions of the peripheral seam together.

[0024] Optionally, the first and second regions of the peripheral seam are secured together by stitching. Alternatively or additionally, the first and second regions of the peripheral seam may be secured together by one or more rivets or other mechanical fasteners.

[0025] The first and second regions of the peripheral seam may be overlapped.

[0026] Embodiments according to both the first and second aspects of the invention may be configured such that each of the fabric layers is woven and comprises a plurality of yarns, and at least some of the yarns of one of the fabric layers interweave with at least some of the yarns of the other of the layers to define the peripheral seam, the peripheral seam thereby being woven and integrated into the structure of the layer. [Brief explanation of the drawings]

[0027] In order that the invention may be more readily understood and further features thereof may be appreciated, embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, in which: [Figure 1] FIG. 1 is a top plan view of a partially assembled airbag according to the first and second embodiments of the present invention. [Figure 2] 2 is a top plan view of the airbag of FIG. 1 showing the first inlet region of the inflatable chamber overlapping with the other two regions of the inflatable chamber. [Figure 3] 3 is a bottom view of the airbag of FIG. 2 showing the two other regions of the inflatable chamber in more detail. [Figure 4] FIG. 3 is a cross-sectional view taken along line VV in FIG. [Figure 5] 1 is a schematic perspective view showing an airbag in combination with an inflator prior to inflation; [Figure 6] FIG. 10 is a top view illustrating the inlet region of the inflatable chamber in an inflated state. [Figure 7] FIG. 10 is a perspective view illustrating the inlet region of the inflatable chamber in an inflated state. DETAILED DESCRIPTION OF THE INVENTION

[0028] Aspects and embodiments of the present invention will now be described with reference to the accompanying drawings, in which: Further aspects and embodiments will be apparent to those skilled in the art.

[0029] The inventions disclosed herein are suitable for implementation in a variety of different types of airbags, such as driver airbags, passenger airbags, rear seat passenger airbags, knee airbags, thorax airbags, side airbags, inflatable side curtains, and pedestrian airbags of the type intended to inflate over a portion of the exterior of a vehicle to provide protection to pedestrians in the event of a vehicle collision.

[0030] Illustrated in FIG. 1 is an airbag 10 partially constructed in accordance with the present invention, the airbag being shown laid out flat in an uninflated condition.

[0031] Airbag 10 is formed from two substantially identical flexible fabric layers 11, 12. Layers 11, 12 are shown in an overlapping arrangement in Figure 1, with upper layer 11 extending over lower layer 12. Upper layer 11 and lower layer 12 are interconnected by a peripheral seam 13 that extends around and defines a boundary 14 of a single inflatable chamber 15 between the two layers.

[0032] In a preferred embodiment of the present invention, the interconnected layers 11, 12 of the airbag 10 are proposed to be woven simultaneously on a single loom by a so-called "one-piece weaving" technique, in which the yarns of one layer are interwoven with the yarns of the other layer in specific areas to define the peripheral seam 13. In such an embodiment, the resulting peripheral seam 13 is thus woven as an integral part of both fabric layers 11, 12, while the layers remain separated from one another inside the boundary of the peripheral seam 13, thereby defining the inflatable chamber 15. As shown in FIG. 1 , the yarns of the two layers 11, 12 may also be interwoven in other areas 16 to interconnect the two layers 11, 12 inside the boundary 14 of the peripheral seam 13. In the airbag shown in FIG. 1 , the other interwoven areas 16 define an internal seam arrangement, thereby creating a series of generally parallel inflatable cells 17 within the inflatable chamber 15 formed between the layers 11, 12.

[0033] It should be understood, however, that the airbags of the present invention may be particularly suited for manufacture by one-piece weaving techniques of the type described above, but are not limited to the use of such techniques. Indeed, in other embodiments, it is contemplated that peripheral seam 13, and any necessary interior seams, such as those shown in area 16 of FIG. 1, may be formed in other convenient ways apparent to those skilled in the art. For example, it is contemplated that in some embodiments, fabric layers 11, 12 may be formed entirely separately from one another as separate sheets and then interconnected by seams that may be formed by conventional stitching to interconnect fabric layers 11, 12, and / or may be made using an adhesive to bond fabric layers 11, 12 together, or may further be formed by the application of heat to fuse fabric layers 11, 12 together.

[0034] 1, peripheral seam 13 is formed by the one-piece weaving technique described above, and it will be observed that peripheral seam 13 has a lateral interconnect width w where the yarns of the two layers 11, 12 interweave, thereby interconnecting layers 11, 12. As will be observed, interconnect width w may vary somewhat along peripheral seam 13, such that some areas of peripheral seam 13 are wider than other areas.

[0035] For the particular airbag 10 shown in Figure 1, the interconnected fabric layers 11, 12 are observed to have a very approximate elongated rectangular shape. More particularly, at one end (the left end in Figure 1), the fabric layers 11, 12 are each observed to be shaped to define a centrally located, somewhat L-shaped structure 11a, 12a positioned between a pair of substantially identically shaped protruding wings 11b, 12b. A peripheral seam 13 interconnects the two fabric layers 11, 12 around their entire periphery, including the wings 11b, 12b and the L-shaped structures, except for a short length along the aligned L-shaped structures 11a, 12a, which remains unconnected, thereby defining a fluid inlet 19 to the inflatable chamber 15. The aligned and interconnected L-shaped structures 11 a, 12 a of the two fabric layers 11, 12 cooperate to define a first region 20 of the inflatable chamber 15, while the aligned and interconnected wings 11 b, 12 b of the two fabric layers 11, 12 cooperate to define respective separate wing regions 21 of the inflatable chamber 15. More specifically, the first region of the inflatable chamber 15 defines an inlet region of the inflatable chamber 15 that is configured to connect to an inflator, as described in more detail below.

[0036] 1, it can be seen that one pair of wings 11b, 12b of the fabric layers are interconnected by a first linear region 22 of the peripheral seam 13, and the other pair of wings 11b, 12b are interconnected by a second linear region 23 of the peripheral seam 13. The first and second linear regions 22, 23 of the peripheral seam 13 may be of equal length to one another and may be respective boundary portions of respective wing regions 21 of the inflatable chamber 15. As can be appreciated, the first and second regions 22, 23 of the peripheral seam 13 are peripherally spaced from one another in the sense that they are each located at respective spaced locations around the seam 13. Further, in the particular airbag configuration shown in FIG. 1 , the aforementioned first and second linear regions 22, 23 of the peripheral seam 13 each have a larger interconnect width w than elsewhere along the seam 13, such as the region indicated by reference numeral 24 along the side of the main central area of ​​the inflatable chamber 15, which has a relatively narrower interconnect width w. However, this is not considered an essential aspect of the present proposal, and it is contemplated that in other embodiments, the first and second linear regions 22, 23 of the peripheral seam 13 may have a smaller interconnect width w than elsewhere along the seam 13. For example, embodiments are contemplated in which the interconnect width w of the peripheral seam 13 varies around the seam as a function of distance from a reference point. An example reference point X is shown in FIG. 1 , located along the peripheral seam 13 at approximately the longitudinal center along the length of the airbag 10, where the airbag 10 is at its narrowest width. It is envisioned that the interconnect width w will be greater in regions of the circumferential seam distal to reference point X than in regions of the circumferential seam proximal to reference point X. Thus, for example, particularly for larger airbags, embodiments are possible in which regions of circumferential seam 13 away from reference point X may actually have a larger interconnect width w than the interconnect widths of the first and second regions 22, 23.

[0037] Referring now to FIG. 2, the airbag 10 is shown according to a subsequent step in its construction. In particular, FIG. 2 shows the airbag 10 after the two wing regions 21 of the inflatable chamber 15 have been manipulated and moved below the inlet region 20 so that the respective first and second linear regions 22, 23 of the peripheral seam 13 overlap one another. The overlapping relationship of the first and second linear regions 22, 23 of the peripheral seam 13 is most clearly illustrated in the cross-sectional view of FIG. 4. In this configuration, it can be observed that a portion of the inlet region 20 of the inflatable chamber 15 overlaps over a portion of each wing region 21. Note further that in this configuration, the two wing regions 21 of the inflatable chamber 15 are not rotated or folded over themselves; thus, the inlet region wing fabric layer 12 is positioned over the top of the upper fabric layer 11 of each wing region 21.

[0038] The overlapping first and second linear regions 22, 23 of the peripheral seam 13 are then secured to one another. In a preferred embodiment, this is accomplished by creating one or more stitches 25 to form a connection interconnecting the first and second regions 22, 23 of the peripheral seam 13. This is most clearly shown in FIG. 3, which shows an end region of the airbag 10 from below. By connecting the first and second regions 22, 23 of the peripheral seam 13 to one another, the two wing regions 21 of the inflatable chamber 15 are also interconnected. However, it is contemplated that in alternative embodiments, the regions 22, 23 of the peripheral seam 13 may be secured to one another in other convenient ways apparent to those skilled in the art. For example, in some embodiments, it is contemplated that the regions 22, 23 may be secured to one another by bonding the regions 22, 23 together using an adhesive, or may be fused together using heat. In other embodiments, it is contemplated that the regions 22, 23 may be secured to one another via the use of rivets or other such fasteners.

[0039] It should be understood that Figure 3 illustrates a pair of optional mounting tabs 26 of the airbag 10, which are not shown in Figures 1 and 2. Each mounting tab 26 projects outward from a respective wing region 21. The mounting tabs 26 may be provided to facilitate securing the airbag 10 to the vehicle structure. It should be understood that in other embodiments, the mounting tabs 26 may be provided at other locations around the airbag.

[0040] It is believed that the or each suture line 25 securing the first and second regions 22, 23 of the peripheral seam 13 together is preferably formed entirely within the interconnect width w of the peripheral seam in those regions.

[0041] With reference to FIG. 2, it should be noted that in the illustrated embodiment, the two wing regions 21 of the inflatable chamber 15 are substantially mirror images across the connection formed by the stitching 25 that interconnects the first and second regions 22, 23 of the peripheral seam.

[0042] 5, the completed airbag 10 is shown in combination with an inflator 27, which may be, for example, a gas generator of a type known per se. The inflator 27 has an elongated, generally cylindrical shape and is connected to the fluid inlet 19 of the airbag 10 by inserting it into the inlet region 20 of the inflatable chamber 15 so that the majority of the inflator's length is located inside the inlet region 20. A clamp 28 is provided around the fabric of the inlet region 20 adjacent the fluid inlet 19, thereby securing the inflator to the airbag 10. As will be understood by those skilled in the art, the inflator 27 includes a series of gas outlets positioned inside the inlet region 20 of the inflatable chamber 15, and the exposed end of the inflator includes an electrical connector 29 for connection to a circuit, typically including a crash sensor and an electronic control unit, operable to detect the occurrence of an impact or collision and, based thereon, transmit an activation signal to the inflator to activate the inflator. Actuation of the inflator is effective to direct a flow of inflation gas into the inlet region 20 of the inflatable chamber 15, from which the inflation gas is directed into the main region of the inflatable chamber 15 for inflating the airbag 10, and from there into the two wing regions 21, as generally indicated by the arrows in FIG. 5.

[0043] 6 and 7, the airbag 10 described above is illustrated in an inflated state, depicting its shape and configuration after activation of the inflator 27 and, therefore, inflation of the inflatable chamber 15. As shown, the inlet region 20 and two wing regions 21 achieve an inflated configuration in which the fabric layers 11, 12 are forced apart by inflation gas from the inflator 27.

[0044] As will be appreciated, if the circumferentially spaced apart regions 22, 23 of the circumferential seam 13 were not interconnected and secured as described above, and the two wing regions 21 of the inflatable chamber 15 were interconnected below the inlet region 20, the airbag 10 would naturally achieve a generally flat, two-dimensional inflated shape upon inflation, with the circumferential seam 13 following a generally flat path around the airbag 10. However, because of the manner in which the circumferentially spaced apart regions 22, 23 of the circumferential seam 13 are actually interconnected and secured to one another adjacent the inlet region 21, the effect of their interconnection is to produce a three-dimensional inflated shape for the inflatable chamber 15 upon inflation of the airbag, with the circumferential seam 13 instead following a non-planar path. This is most clearly illustrated in Figure 7, where it can be seen that the inlet region 20 of the inflatable chamber 15 abuts the wing regions 21 in the inflated configuration, thereby i) biasing the wing regions 21 slightly downward and ii) biasing the inlet region 20 slightly upward, such that the region of the peripheral seam extending around and bounding the wing regions 21 of the inflatable chamber extends out of plane with the region of the peripheral seam extending around and bounding the inlet region 20. The inflated shape of the inflatable chamber 15 thereby achieves a two-tiered configuration in the area of ​​the inflator 27, the inlet region 20, and the wing regions 21, with the inflated shape of the inlet region 20 representing the upper tier and the inflated shape of the wing regions 21 representing the lower tier. Furthermore, because the inflated inlet region 20 abuts the inflated wing regions 21, the inlet region 20 can provide some support to the wing regions 21, and vice versa.

[0045] 6 and 7, when the airbag 10 is inflated, the inlet region 20 of the inflatable chamber overlaps the interconnected first and second regions 22, 23 of the peripheral seam 13 and is overlapped with the two wing regions 21 such that the lower fabric layer 12 of the inlet region 20 abuts the upper fabric layer 11 of the wing regions 21. Furthermore, with reference to FIG. 5, it should also be understood that when the airbag 10 is inflated, one of the wing regions 21 of the inflatable chamber 15 is positioned adjacent to the inflator 27 and assumes an inflated configuration abutting the inflator 27, thereby providing potential support for the inflator 27 and providing a cushioning effect to protect the vehicle occupant (or pedestrian, in the case of a pedestrian airbag) from potentially harmful impact with the inflator 27 in the event of an accident. The fact that the wing region 21 is positioned adjacent to the inflator 27 also helps prevent contact with the inflator 27, which can become very hot when activated, thereby providing some protection to the occupant (or pedestrian) from the risk of burns.

[0046] The features disclosed in the above description or the following claims or the accompanying drawings, whether presented in a particular form or in terms of means for performing a disclosed function or methods or steps for conveniently obtaining a disclosed result, may be used separately or in any combination of such features to realize the invention in diverse forms thereof.

[0047] While the present invention has been described in conjunction with the exemplary embodiments set forth above, many equivalent modifications and variations will be apparent to those skilled in the art given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various modifications to the described embodiments may be made without departing from the scope of the invention.

[0048] For the avoidance of doubt, any theoretical explanations provided herein are provided for the purpose of enhancing the understanding of the reader, and the inventors do not wish to be bound by any of these theoretical explanations.

[0049] Any section headings used herein are for organizational purposes only and should not be construed as limiting the subject matter described.

[0050] Throughout this specification, including the claims that follow, unless the context requires otherwise, the words "have," "comprise," and "include," as well as variations such as "having," "comprises," "comprising," and "including," are understood to refer to the inclusion of a stated integer or step or group of integers or steps, but not to the exclusion of any other integer or step or group of integers or steps. It must be noted that as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural references unless the context requires 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 use of the antecedent "about," it will be understood that the particular value forms another embodiment. The term "about" in reference to numerical values ​​is optional and means, for example, + / - 10%.

[0051] The terms "preferred" and "preferably" are used herein to refer to embodiments of the invention that may provide certain benefits, under some circumstances. It is understood, however, that other embodiments may also be preferred, under the same or different circumstances. Thus, the recitation of one or more preferred embodiments does not mean or imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the present disclosure or from the claims.

Claims

1. 1. An inflatable airbag (10) for a motor vehicle, the airbag (10) comprising a pair of superimposed fabric layers (11, 12) interconnected by a peripheral seam (13) extending around and defining a boundary (14) of a single inflatable chamber (15) between the layers (11, 12), the inflatable chamber (15) having an inlet region (20) with a fluid inlet (19) connected to an inflator (27), the airbag (10) comprising: an inflatable airbag (10) wherein first and second circumferentially spaced apart regions (22, 23) of the peripheral seam (13) are secured to one another so as to overlap one other region (21) and thereby create an inflated shape for the chamber (15) upon inflation of the airbag (10) by a flow of gas from the inflator (27), the inflated shape being characterized by at least one other region (21) of the inflatable chamber (15) being located adjacent to the inflator (27) upon inflation of the airbag (10).

2. 2. The airbag (10) of claim 1, wherein the inflated shape is further characterized by at least one other region (21) of the inflatable chamber (15) abutting the inflator (27) upon inflation of the airbag (10).

3. 3. The airbag (10) according to claim 1 or 2, wherein the inflated shape has a two-stage configuration in which the inlet region (20) abuts against at least one of the other regions (21).

4. 4. The airbag (10) according to claim 1, wherein the pair of overlapping fabric layers (11, 12) comprises an upper fabric layer (11) and a lower fabric layer (12), and the inlet region (20) of the inflatable chamber (15) is overlapped with the or each other region (21) such that the lower fabric layer (12) of the inlet region (20) abuts the upper fabric layer (11) of the or each other region (21) when the airbag (10) is inflated.

5. 5. The airbag (10) of claim 1, wherein the first and second regions (22, 23) of the peripheral seam (13) are secured to one another such that the inlet region (20) of the inflatable chamber (15) overlaps two other separate regions (21) of the inflatable chamber (15).

6. 6. The airbag (10) of claim 5, wherein the two separate other regions (21) of the inflatable chamber (15) are of substantially the same shape and configuration.

7. 7. The airbag (10) of claim 5 or 6, wherein the first region (22) of the peripheral seam (13) bounds a portion of the separate other region (21) of one of the inflatable chambers (15), and the second region (23) of the peripheral seam (13) bounds a portion of the separate other region (21) of the other of the inflatable chambers (15), and the two separate other regions (21) of the inflatable chambers (15) are interconnected by connecting the first and second regions (22, 23) of the peripheral seam (13) to each other.

8. 8. The airbag (10) of claim 7, wherein the two separate other regions (21) of the inflatable chamber (15) are substantially mirror images of each other across a connection (25) between the first region (22) and the second region (23) of the peripheral seam (13).

9. The airbag (10) of any one of claims 1 to 8, wherein the inlet region (20) of the inflatable chamber (15) overlies the first and second regions (22, 23) of the peripheral seam (13).

10. 10. The airbag (10) according to any one of claims 1 to 9, wherein the peripheral seam (13) has an interconnection width (w) along which the fabric layers (11, 12) are interconnected, and the first and second regions (22, 23) of the peripheral seam (13) are secured to one another by a connection (25) formed entirely within the interconnection width (w).

11. 11. The airbag (10) of claim 10, wherein the interconnect width (w) varies along the peripheral seam (13) and is greater in the first and second regions (22, 23) of the peripheral seam (13) than elsewhere along the seam (13).

12. 12. The airbag (10) according to claim 10 or 11, wherein the connection comprises a stitch (25).

13. The airbag (10) according to any one of the preceding claims, wherein the first and second regions (22, 23) of the peripheral seam (13) are secured to one another by stitching (25).

14. The airbag (10) according to any one of the preceding claims, wherein the first and second regions (22, 23) of the peripheral seam (13) are overlapped.

15. 15. The airbag (10) of any one of claims 1 to 14, wherein each of the fabric layers (11, 12) is woven and comprises a plurality of yarns, at least some of the yarns of one of the fabric layers (11) interwoven with at least some of the yarns of the other of the layers (12) to define the peripheral seam (13), the peripheral seam (13) thereby being woven and integral with the structure of the layers (11, 12).

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