Inflatable airbag

Abstract

An inflatable airbag (10) for a vehicle is disclosed. The airbag (10) comprises a pair of overlapping fabric layers (11, 12) interconnected by a peripheral seam (13), the peripheral seam (13) extends around the layers (11, 12) and defines boundaries (14) of a single inflatable chamber (15) between the layers (11, 12). The inflatable chamber (15) has an inlet region (20) including a fluid inlet (19) connected to an inflator (27). The first and second peripherally spaced regions (22, 23) of the surrounding core (13) are fixed to each other so that the inlet region (20) overlaps with at least one other region (21) of the inflatable chamber (15) to induce an inflated shape in the chamber (15) when the airbag (10) is inflated by the flow of gas from the inflator (27), and the inflated shape is characterized by at least one other region (21) of the inflatable chamber (15) that is placed adjacent to the inflator (27) when the airbag (10) is inflated.

Description

Technology Field

[0001] The present invention relates to an inflatable airbag. More specifically, the present invention relates to an inflatable airbag for an automobile safety device. Background Technology

[0002] It is currently very well known that airbags are provided in automobiles to protect occupants in the event of an accident, and more recently, that airbags are arranged to inflate across the exterior of the vehicle to protect pedestrians in the event of being struck by a vehicle. All types of airbags have become considerably more sophisticated over the years, and many airbags now have specific and somewhat complex shapes dictated by specific functions, required inflation characteristics, and the shape and configuration of the vehicle parts on which they are mounted or intended to inflate. These airbags are initially provided in the form of tightly folded and / or rolled packages within airbag modules mounted in the vehicle.

[0003] Typically, airbags are manufactured from fabric and typically comprise two or more fabric layers interconnected by seams. In many cases, the fabric layers are woven separately and then stitched together to provide stitched seams, but in some cases, the layers may be bonded with adhesive to form combined seams or heat-fused together to form fused seams. However, in some cases, two fabric layers may be woven simultaneously through a so-called one-piece-weaving technique in which the yarns of one fabric layer are interwoven with the yarns of the other fabric layer in some areas to create a woven seam that is integrated into the weave of the airbag fabric in these areas.

[0004] Airbags generally have an inlet that is typically directly connected to an inflator, such as a gas generator, and allows the inflow of inflation gas from the inflator to inflate the airbag. These inflators are configured to generate a large volume and aggressive flow of inflation gas, and thus the force applied to the area of ​​the airbag where the inlet is provided can be extremely large. In some situations, this can make it difficult to achieve the desired inflation characteristics for the airbag, especially if there are limitations on the possible positions of the inflator. Additionally, inflators can pose a risk of injury to vehicle occupants if they must be positioned very close to the occupants; for example, in the event of a collision, they can pose a risk of injury through impact with the inflator. Inflators can also become very hot during operation, which can pose a risk of burns to occupants located very close to the inflator. Therefore, for some airbag systems, it has been found that it can be difficult to properly position the inflator to ensure accurate inflation characteristics while guaranteeing that vehicle occupants located very close to the inflator are adequately protected from the risk of injury resulting from contact or impact with the inflator.

[0005] The present invention was devised in consideration of the above considerations.

[0006] According to a first aspect of the present invention, an inflatable airbag for an automobile is provided; the airbag comprises a pair of overlapping fabric layers interconnected by a peripheral seam, said peripheral seam extending around said layers and defining the boundaries of a single inflatable chamber between said layers; said inflatable chamber has an inlet region comprising a fluid inlet connected to an inflator; and the airbag is characterized in that first and second peripherally spaced regions of said peripheral seam are fixed to each other such that said inlet region overlaps with at least one other region of said inflatable chamber to induce an inflated shape in said chamber upon inflation of the airbag by a flow of gas from said inflator, said inflated shape is characterized by said other region of said inflatable chamber that is positioned adjacent to said inflator upon inflation of the airbag.

[0007] Optionally, the inflated shape is further characterized by at least one of the other regions of the inflatable chamber that is supported by the inflator during the inflation of the airbag.

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

[0009] Conveniently, the pair of the overlapping fabric layers comprises an upper fabric layer and a lower fabric layer, and the inlet area of ​​the inflatable chamber overlaps with one or each of the other areas so that when the airbag is inflated, the lower fabric layer of the inlet area is supported against the upper fabric layer of one or each of the other areas.

[0010] Optionally, the first and second regions of the surrounding periphery are fixed to each other such that the inlet region of the inflatable chamber overlaps with two separate regions of the inflatable chamber.

[0011] The inlet area of ​​the expandable chamber may be positioned above the first and second areas of the surrounding core.

[0012] According to a second aspect of the present invention, an inflatable airbag for a vehicle is provided; the airbag comprises a pair of overlapping fabric layers interconnected by a peripheral seam, said peripheral seam extending around said layers and defining boundaries of a single inflatable chamber between said layers; and the airbag is characterized in that: first and second peripherally spaced regions of said peripheral seam are fixed to each other to induce a three-dimensional inflated shape in said chamber upon inflation of the airbag such that said peripheral seam follows a non-planar path.

[0013] In some embodiments of the second aspect of the present invention, the first and second regions of the peripheral core are spaced apart from each other and fixed so that the first region of the inflatable chamber overlaps with at least one other region of the inflatable chamber, thereby providing a two-layer inflated configuration to at least a portion of the inflatable chamber when the airbag is inflated.

[0014] Optionally, the first region of the expandable chamber is placed over the first and second regions of the surrounding core.

[0015] For convenience, the first region of the inflatable chamber may define an inlet to the inflatable chamber, and the inlet is configured to engage with an inflator.

[0016] In some embodiments of the second aspect of the present 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 one or each of the other regions so that when the airbag is inflated, the lower fabric layer of the first region is supported against the upper fabric layer of one or each of the other regions.

[0017] Optionally, the first and second regions of the surrounding core are fixed to each other such that the first region of the expandable chamber overlaps with two separate regions of the expandable chamber.

[0018] In embodiments of the first or second aspects of the present invention having two distinct regions of the expandable chamber, these regions may have substantially the same shape and configuration.

[0019] In some embodiments of both aspects of the present invention, the first region of the peripheral core is bordered by a portion of one of the distinct other regions of the inflatable chamber, the second region of the peripheral core is bordered by a portion of the other of the distinct other regions of the inflatable chamber, and the two distinct other regions of the inflatable chamber are interconnected by the connection of the first region and the second region of the peripheral core.

[0020] Optionally, the two distinct regions of the expandable chamber may be substantially mirror-symmetric with respect to the connection between the first region and the second region of the peripheral core.

[0021] Embodiments according to both the first and second aspects of the present invention may be configured such that the peripheral core has an interconnection width in which the fabric layers are interconnected, and the first and second regions of the peripheral core are fixed to each other by a connection formed entirely within the interconnection width.

[0022] Optionally, the interconnect width varies along the periphery core and is larger in the first and second regions of the periphery core than elsewhere along the core.

[0023] Alternatively, the interconnect width varies along the periphery core and is narrower in the first and second regions of the periphery core than elsewhere along the core.

[0024] The connection may include stitching. Alternatively or additionally, the connection may include an adhesive or may be formed by the application of heat to fuse the first and second regions of the peripheral seam together. Alternatively or additionally, the connection may include one or more rivets or other mechanical fasteners to secure the first and second regions of the peripheral seam together.

[0025] Optionally, the first and second regions of the peripheral seam are secured to each other by stitching. Alternatively or additionally, the first and second regions of the peripheral seam may be secured to each other by one or more rivets or other mechanical fasteners.

[0026] The first and second regions of the surrounding deliberation may overlap.

[0027] An embodiment according to both the first and second aspects of the present invention may be configured such that each of the fabric layers is woven and comprises a plurality of threads, and at least some of the threads of one fabric layer are interwoven with at least some of the threads of another layer to define the peripheral seam so that the peripheral seam is woven and integrated into the structure of the layers. Brief explanation of the drawing

[0028] In order to make the present invention more easily understood and to make its additional features understandable, embodiments of the present invention are now described by way of example with reference to the accompanying drawings. FIG. 1 is a top view of a partially assembled airbag according to both the first and second aspects of the present invention. FIG. 2 is a top view of the airbag of FIG. 1, illustrating a first inlet area of ​​the inflatable chamber that overlaps with two other areas of the inflatable chamber. FIG. 3 is a view of the airbag of FIG. 2 seen from below, illustrating the two different regions of the inflatable chamber in more detail. Figure 4 is a cross-sectional view taken along line VV of Figure 2. FIG. 5 is a schematic perspective view illustrating an airbag combined with an inflator before inflation. FIG. 6 is a top view illustrating the inlet area of ​​an expandable chamber in an expanded state. FIG. 7 is a perspective view illustrating the inlet area of ​​an expandable chamber in an expanded state. Specific details for implementing the invention

[0029] Now, aspects and embodiments of the present invention will be discussed with reference to the accompanying drawings. Further aspects and embodiments will be apparent to those skilled in the art.

[0030] The invention disclosed herein is suitable for implementation in a wide variety of airbags, such as, for example, driver airbags, front passenger airbags, rear passenger airbags, knee airbags, chest airbags, side airbags, inflatable side curtains, and pedestrian airbags of a type intended to inflate across the exterior of a vehicle to provide protection to a pedestrian in the event of being struck by a vehicle.

[0031] FIG. 1 shows an airbag (10) partially constructed according to the present invention, the airbag is shown in an uninflated state and is laid flat.

[0032] The airbag (10) is formed of two flexible fabric layers (11, 12) having substantially the same shape. The layers (11, 12) are shown in FIG. 1 as being arranged in an overlapping manner, with the upper layer (11) extending across the lower layer (12). The upper and lower layers (11, 12) are interconnected by a periphery seam (13), which extends around the two layers and defines the boundaries (14) of a single inflatable chamber (15) between the two layers.

[0033] In preferred embodiments of the present invention, it is proposed that interconnected layers (11, 12) of the airbag (10) be woven simultaneously on a single loom through a so-called “integral-weaving” technique in which threads of one layer of the layers are interwoven with threads of the other layer in specific areas to define a peripheral seam (13). In these embodiments, the resulting peripheral seam (13) is therefore integral with both of the fabric layers (11, 12) and woven as part thereof, while the layers are kept separate from each other within the boundaries of the peripheral seam (13) to define an inflatable chamber (15).

[0034] As illustrated in FIG. 1, the threads of the two layers (11, 12) may also be interwoven in other sections (16) to interconnect the two layers (11, 12) within the boundaries (14) of the surrounding seams (13). In the airbag illustrated in FIG. 1, the other interwoven sections (16) define an array of internal seams to create a series of generally parallel inflatable cells (17) within an inflatable chamber (15) formed between the layers (11, 12).

[0035] However, it should be understood that while the airbag of the present invention may be particularly suitable for manufacturing through the type of integral weaving technique described above, it is not limited to the use of such technique. In fact, it is conceived that any necessary inner seams, such as the peripheral seams (13) and those indicated in the zones (16) of FIG. 1 in other embodiments, may also be formed in other convenient ways that are obvious to those skilled in the art. For example, in some embodiments, the fabric layers (11, 12) may be formed completely individually from each other as separate sheets and then interconnected by seams that may be formed by conventional stitching to interconnect the fabric layers (11, 12) and / or created using an adhesive to bond the fabric layers (11, 12) together, or even formed by the application of heat to fuse the fabric layers (11, 12) together.

[0036] In the embodiment illustrated in FIG. 1, in which the peripheral core (13) is formed through the aforementioned integral weaving technique, it will be observed that the peripheral core (13) has a transverse interconnection width (w) in which the threads of two layers (11, 12) are interwoven to interconnect the layers (11, 12). As will be observed, the interconnection width (w) may vary somewhat along the peripheral core (13) so that some areas of the peripheral core (13) are wider than other areas.

[0037] In the case of the specific airbag (10) illustrated in FIG. 1, it will be observed that the interconnected fabric layers (11, 12) have a very roughly elongated rectangular shape. More specifically, it will be observed that at one end (left end of FIG. 1), each of the fabric layers (11, 12) is shaped to define a centrally located and somewhat L-shaped formation (11a, 12a) positioned between a pair of protruding wings (11b, 12b) of substantially the same shape. The periphery seam (13) interconnects the two fabric layers (11, 12) around their entire periphery, including the wings (11b, 12b) and the L-shaped formations, except for a short distance along the aligned L-shaped formations (11a, 12a) that remains unconnected to define the fluid inlet (19) to the inflatable chamber (15). Aligned and interconnected L-shaped formations (11a, 12a) of two fabric layers (11, 12) cooperate to define a first region (20) of the inflatable chamber (15), while aligned and interconnected wings (11b, 12b) of two fabric layers (11, 12) cooperate to define each distinct wing region (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) configured to be connected to an inflator, as described in more detail below.

[0038] It will be observed in FIG. 1 that one pair of wings (11b, 12b) of the fabric layer is interconnected by the first straight region (22) of the peripheral core (13), while the other pair of wings (11b, 12b) is interconnected by the second straight region (23) of the peripheral core (13). The first and second straight regions (22, 23) of the peripheral core (13) may have the same length as each other and may each be bounded by a portion of the wing region (21) of the inflatable chamber (15). As is understood, the first and second regions (22, 23) of the peripheral core (13) are peripherally spaced apart from each other in the sense that they are each located at separate positions around the core (13). Additionally, in the specific airbag configuration illustrated in FIG. 1, it will be noted that the aforementioned first and second straight regions (22, 23) of the periphery seam (13) each have a greater interconnection width (w) than other places along the seam (13), such as the regions indicated by reference numeral 24 along the sides of the main central section of the inflatable chamber (15) having a relatively narrow interconnection width (w). However, this is not considered to be an essential aspect of the present proposal, and in other embodiments, it is conceived that the first and second straight regions (22, 23) of the periphery seam (13) may have a smaller interconnection width (w) than other places along the seam (13). For example, embodiments are conceived in which the interconnection width (w) of the periphery seam (13) varies around the seam as a function of distance from a reference point. An exemplary reference point X is shown in FIG. 1, located along the peripheral seam (13) at a central position along the length of the airbag (10), where the width of the airbag (10) is narrowest. It is conceived that the interconnection width (w) will be greater in the peripheral seam regions that are far from the reference point X than in the peripheral seam regions that are close to the reference point X.Accordingly, for example, in the case of particularly large airbags, embodiments are possible in which the regions of the surrounding seam (13) far from the reference point X actually have an interconnection width (w) greater than the interconnection width of the first and second regions (22, 23).

[0039] Now, considering FIG. 2, the airbag (10) is illustrated according to subsequent steps of its configuration. In particular, FIG. 2 illustrates 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 their respective first and second straight regions (22, 23) of the periphery seam (13) are placed over each other in an overlapping state. The overlapping relationship of the first and second straight regions (22, 23) of the periphery seam (13) is most clearly illustrated in the cross-sectional view of FIG. 4. In this configuration, it will be observed that a portion of the inlet region (20) of the inflatable chamber (15) overlaps across the top of each portion of the wing region (21). Additionally, it should be noted that in this configuration, the two wing regions (21) of the expandable chamber (15) are not rotated or folded on themselves, and thus the lower fabric layer (12) of the inlet region (20) is placed across the top of the upper fabric layer (11) of each wing region (21).

[0040] Then, the overlapping first and second straight regions (22, 23) of the surrounding seam (13) are fixed to each other. In preferred embodiments, this is achieved by creating one or more stitching (25) lines to form a connection that interconnects the first and second regions (22, 23) of the surrounding seam (13).

[0041] This is most clearly illustrated in FIG. 3, which illustrates the end regions of the airbag (10) as can be seen below. The connection of the first and second regions (22, 23) of the peripheral seam (13) to each other also interconnects the two wing regions (21) of the inflatable chamber (15). However, it should be noted that in alternative embodiments, the regions (22, 23) of the peripheral seam (13) are conceived to be secured to each other in other convenient ways that are obvious to those skilled in the art. For example, in some embodiments, the regions (22, 23) are conceived to be secured to each other by using an adhesive to join the regions (22, 23) together, or even fused together using the application of heat. In other embodiments, the regions (22, 23) are conceived to be secured to each other through the use of rivets or other such fasteners.

[0042] It should be understood that FIG. 3 illustrates a pair of optional mounting tabs (26) of an airbag (10) that are not illustrated in FIG. 1 and FIG. 2 at this point. Each mounting tab (26) protrudes outward from each wing area (21). The mounting tabs (26) may be provided to facilitate the securing of the airbag (10) to the structure of the vehicle. As is understood, in other embodiments, the mounting tabs (26) may be provided at other locations around the airbag.

[0043] It is considered desirable that one or each stitching (25) line that secures the first and second regions (22, 23) of the surrounding seam (13) to each other be formed entirely within the interconnection width (w) of the surrounding seam in these regions.

[0044] With reference to FIG. 2, it should be noted that in the illustrated embodiment, the two wing regions (21) of the expandable chamber (15) are substantially mirror-symmetric with respect to the connection formed by stitching (25) that interconnects the first and second regions (22, 23) of the surrounding core.

[0045] Now, considering FIG. 5, the finished airbag (10) is illustrated in combination with an inflator (27), which may be, for example, a gas generator of a type known as itself. The inflator (27) is elongated and generally cylindrical in shape and is connected to the fluid inlet (19) of the airbag (10) by inserting it through the inlet area so that most of the length of the inflator is seated inside the inlet area (20) of the inflatable chamber (15). A clamp (28) is provided around the fabric of the inlet area (20) adjacent to the fluid inlet (19) to secure the inflator to the airbag (10). As understood by those skilled in the art, the inflator (27) thus includes a series of gas outlets located inside the inlet area (20) of the inflatable chamber (15), while the exposed end of the inflator includes an electrical connector (29) for connecting to a circuit that will typically include a collision sensor and an electronic control unit and can operate to detect the occurrence of an impact or collision and transmit an operating signal to the inflator to operate the inflator upon the occurrence of an impact or collision. The operation of the inflator is effective in directing the flow of expansion gas into the inlet area (20) of the inflatable chamber (15), and the expansion gas is directed from the inlet area to the main area of ​​the inflatable chamber (15) and from the main area into the two wing areas (21) to inflate the airbag (10), as generally indicated by the arrows in FIG. 5.

[0046] Now, with reference to FIGS. 6 and FIGS. 7, the aforementioned airbag (10) is illustrated in an inflated state representing the shape and configuration of the airbag after the operation of the inflator (27) and the subsequent inflation of the inflatable chamber (15). As illustrated, both the inlet region (20) and the two wing regions (21) achieve an inflated configuration in which the fabric layers (11, 12) are forced to be separated by the inflation gas from the inflator (27).

[0047] As is understood, with the two wing regions (21) of the inflating chamber (15) interconnected below the inlet region (20), if the peripherally spaced regions (22, 23) of the peripheral seam (13) were not interconnected and fixed as described above, the airbag (10) would naturally achieve a generally flat two-dimensional inflated shape with the peripheral seam (13) following a generally flat path around the airbag (10) upon inflation. However, due to the way the peripherally spaced regions (22, 23) of the peripheral seam (13) are actually interconnected and fixed adjacent to the inlet region (21), the effect of their interconnection is to induce a three-dimensional inflated shape in the inflatable chamber (15) upon inflation of the airbag, in which the peripheral seam (13) instead follows a non-flat path. This is most clearly illustrated in FIG. 7, where the inlet region (20) of the inflatable chamber (15) is supported against the wing regions (21) in their inflated configurations, thereby i) forcing the wing region (21) slightly downward and ii) forcing the inlet region (20) slightly upward, so that the surrounding deep regions extending around and bounded by the wing regions (21) of the inflatable chamber extend out of plane together with the surrounding deep regions extending around and bounded by the inlet region (20). By this, the inflated shape of the inflatable chamber (15) achieves a two-layer configuration in the regions of the inflator (27), the inlet region (20), and the wing regions (21), wherein the inflated shape of the inlet region (20) represents the upper layer and the inflated shape of the wing regions (21) represents the lower layer. Additionally, since the expanded inlet area (20) is supported against the expanded wing areas (21), the inlet area (20) can provide some support to the wing areas (21) and vice versa.

[0048] Also, as will be understood from FIGS. 6 and 7, when the airbag (10) is inflated, the inlet region (20) of the inflatable chamber is placed over the interconnected first and second regions (22, 23) of the surrounding seam (13) and overlaps with the two wing regions (21) so that the lower fabric layer (12) of the inlet region (20) is supported against the upper fabric layer (11) of the wing regions (21). Also, with reference to FIG. 5, when the airbag (10) is inflated, one of the wing regions (21) of the inflatable chamber (15) will adopt an inflated configuration that is placed adjacent to and supported by the inflator (27), thereby providing the possibility to support the inflator (27) and providing a cushioning effect to protect the vehicle occupant from potential injury impacts caused by the inflator (27) in the event of an accident. The fact that the wing area (21) is positioned adjacent to the inflator (27) also provides some protection to the occupant (or pedestrian) from the risk of burns, as this helps prevent contact with the inflator (27), which can become very hot during operation.

[0049] Features or methods or processes for obtaining disclosed results disclosed in the foregoing description, the claims set forth below, or the attached drawings, which are expressed in a specific form or expressed as means for performing the disclosed function, may be utilized appropriately, separately, or in any combination of such features to realize the present invention in various forms.

[0050] Although the present invention has been described in relation to the exemplary embodiments described above, a number of equivalent modifications and variations will be apparent to those skilled in the art as the present disclosure is provided. Accordingly, the exemplary embodiments of the present invention described above are illustrative and are not to be considered restrictive. Various modifications to the described embodiments may be made without departing from the spirit and scope of the present invention.

[0051] To eliminate any doubt, any theoretical descriptions provided herein are provided for the purpose of improving the reader's understanding. The inventors do not wish to be bound by any of these theoretical descriptions.

[0052] Any section titles used in this specification are for organizational purposes only and should not be construed as limiting the subject matter described.

[0053] Throughout this specification, including the following claims, it will be understood that, unless the context otherwise requires, variations such as the words “have,” “compose,” and “include,” and “having,” “compose,” “composing,” and “include,” imply the inclusion of a specified 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. It should be noted that the singular forms “one” and “above,” as used in this specification and in the appended claims, include multiple references unless the context clearly indicates otherwise. A range may be expressed in this specification as “about” from one specific value and / or “about” another specific value. When such a range is expressed, other embodiments include from one specific value and / or another specific value. Similarly, when values ​​are expressed as approximations using the preceding word “about,” it will be understood that a specific value constitutes another embodiment. In relation to numerical values, the term "about" is optional and means, for example, + / - 10%.

[0054] The terms "preferred" and "preferably" refer to embodiments of the invention that may provide specific advantages under certain circumstances in this specification. However, it should be understood that other embodiments may also be preferred under the same or different circumstances. Accordingly, the reference to one or more preferred embodiments does not imply or suggest that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of this disclosure or the claims.

Claims

Claim 1 As an inflatable airbag (10) for a vehicle, the airbag (10) comprises a pair of overlapping fabric layers (11, 12) interconnected by a peripheral seam (13), the peripheral seam (13) extends around the layers (11, 12) and defines the boundaries (14) of a single inflatable chamber (15) between the layers (11, 12); The airbag (10) has an inlet region (20) including a fluid inlet (19) connected to an inflator (27), wherein the airbag (10) has first and second regions (22, 23) peripherally spaced apart from the surrounding shim (13) are fixed to each other such that the inlet region (20) overlaps with at least one other region (21) of the inflatable chamber (15) to induce an inflated shape in the chamber (15) when the airbag (10) is inflated by the flow of gas from the inflator (27), and the inflated shape is characterized in that when the airbag (10) is inflated, at least one of the other regions (21) of the inflatable chamber (15) is positioned adjacent to the inflator (27). Claim 2 In claim 1, the airbag (10) is characterized in that, when the airbag (10) is inflated, at least one of the other regions (21) of the inflatable chamber (15) is supported against the inflator (27). Claim 3 In claim 1 or 2, the inflated shape is an airbag (10) having a two-tiered configuration in which the inlet region (20) is supported by at least one other region (21). Claim 4 In claim 1, 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) overlaps with one or each of the other regions (21) such that when the airbag (10) is inflated, the lower fabric layer (12) of the inlet region (20) is supported against the upper fabric layer (11) of one or each of the other regions (21), airbag (10). Claim 5 In claim 1, the first and second regions (22, 23) of the surrounding shim (13) are fixed to each other so that the inlet region (20) of the inflatable chamber (15) overlaps with two separate other regions (21) of the inflatable chamber (15), airbag (10). Claim 6 In paragraph 5, the two distinct regions (21) of the inflatable chamber (15) are substantially the same shape and configuration, airbag (10). Claim 7 In claim 5 or 6, the first region (22) of the peripheral seam (13) is bounded by a portion of one of the separate other regions (21) of the inflatable chamber (15), the second region (23) of the peripheral seam (13) is bounded by a portion of the other of the separate other regions (21) of the inflatable chamber (15), and the two separate other regions (21) of the inflatable chamber (15) are interconnected by the connection of the first and second regions (22, 23) of the peripheral seam (13) to each other, airbag (10). Claim 8 In claim 7, the two distinct regions (21) of the inflatable chamber (15) are substantially mirror-symmetric with respect to the connection between the first and second regions (22, 23) of the surrounding seam (13), airbag (10). Claim 9 In claim 1, the inlet region (20) of the inflatable chamber (15) is placed over the first and second regions (22, 23) of the surrounding shim (13), airbag (10). Claim 10 In claim 1, the peripheral seam (13) has an interconnection width (w) in which the fabric layers (11, 12) are interconnected, and the first and second regions (22, 23) of the peripheral seam (13) are fixed to each other by a connection formed entirely within the interconnection width (w), airbag (10). Claim 11 In item 10, the interconnect width (w) varies along the surrounding seam (13) and is larger in the first and second regions (22, 23) of the surrounding seam (13) than elsewhere along the seam (13), airbag (10). Claim 12 In claim 10 or 11, the connection comprises stitching (25), airbag (10). Claim 13 In claim 1, the first and second regions (22, 23) of the surrounding seam (13) are fixed to each other by stitching (25), airbag (10). Claim 14 In claim 1, the first and second regions (22, 23) of the surrounding seam (13) overlap, airbag (10). Claim 15 An airbag (10) according to claim 1, wherein each of the fabric layers (11, 12) is woven and comprises a plurality of threads, and at least some of the threads of one fabric layer (11) are interwoven with at least some of the threads of another layer (12) to define the peripheral seam (13), so that the peripheral seam (13) is woven and incorporated into the structure of the layers (11, 12).

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