A safety arrangement

Abstract

An air-bag for incorporation into the squab of a vehicle seat, the air-bag comprising: a front edge, a rear edge and respective first and second side edges; an open or cut-out region at or near the rear edge; a top layer and an opposing bottom layer; and at each side of the air-bag, a fold arrangement formed between the top and bottom layers, the fold arrangement comprising a length of fabric that extends between the side edges of the top and bottom layers.

Description

[0001] A SAFETY ARRANGEMENT

[0002] This invention relates to a safety invention, and in particular concerns a pelvis restraint cushion.

[0003] It is known to provide pelvis restraint in vehicles such as motor cars. Existing pelvis restraint cushions are located within the squab of a vehicle seat, such as a driver’s seat or passenger seat. In the event of a collision, such a head-on collision, the cushion is inflated. Prior to inflation, the cushion is provided in a generally flat shape. Following inflation, the cushion expands to have a greater thickness across all or substantially all of the area of the seat squab. However, the increase in thickness is greater at the front of the squab (i.e. furthest from the seat back), and is less at the rear of the squab.

[0004] The inflation of the pelvis restraint cushion gives rise to benefits in protecting the occupant.

[0005] Firstly, the seat occupant is lifted generally upwardly with respect to the seat, and is therefore brought into firmer engagement with the seat belt and other parts of the seat structure. This will help to ensure that the occupant is effectively restrained by the seat belt during the crash.

[0006] Further, during a head-on collision, the occupant can be thrown forwardly with respect to the vehicle, and can slide under the seat belt into the region of the car footwell. This phenomenon is known as “submarining”, and can give rise to serious injuries.

[0007] By inflating to a greater additional thickness near the front of the seat squab, compared to the region at the rear of the seat squab, the pelvis restraint cushion is inflated into a shape which is generally wedge-like, and which will therefore tend to prevent the seat occupant from submarining.

[0008] Under the forces involved in a head-on or rear collision, this shape of the pelvis restraint cushion will also help to prevent lumber compression, and related injuries arising from forces acting on the seat occupant.

[0009] It is an object of the invention to provide an improved pelvis restraint cushion of the type described above.

[0010] Accordingly, one aspect of the present invention provides a safety device as set out in claim 1 .

[0011] Preferred features of the invention are set out in the dependent claims. In order that the invention may be more readily understood, embodiments thereof will now be described, with reference to the accompanying figures, in which:

[0012] Figure 1 is a schematic view of a known pelvis restraint cushion;

[0013] Figure 2 shows a first example of a pelvis restraint cushion embodying the invention;

[0014] Figures 3 and 4 show cutaway views through the cushion shown in figure 2;

[0015] Figures 5 to 9 show further examples of pelvis restraint cushions embodying the invention; and

[0016] Figures 10 to 13 show steps in a method of manufacturing a pelvis restraint cushion embodying the invention.

[0017] In some vehicles, a vent is formed in the seat squab, to allow circulation of air, to improve cooling in warm conditions. This vent will generally be located towards the rear of the seat squab, and centrally disposed with respect to the two sides of the seat squab.

[0018] To accommodate this, a pelvis restraint cushion for a seat of this type will be formed to include an open or cut-out region, which in use will be generally aligned with this vent, to prevent the cushion from blocking air passing through the vent.

[0019] Figure 1 shows a schematic view of a known pelvis restraint cushion 1 of this type, in place upon a seat squab 2, and seen from generally directly above. As discussed above, a vent 3 is formed in the squab 2, positioned towards the rear 4 of the squab 2.

[0020] The cushion 1 is anchored to part of the frame of the seat, near a rear portion of the seat squab 2, at spaced apart securing points 5, which are positioned on either side of the seat squab 2.

[0021] The cushion 1 has first and second connection regions 6, which extend forwardly from the securing points 5. The connection regions 6 extend on either side of the vent 3, and do not create any blockage, layer or obstruction immediately over the vent 3. As can be seen in figure 1 , the cushion 1 includes an open or cut out region 7, between the connection regions 6, which is aligned with the vent 3.

[0022] The cushion also includes a main region 8, which is positioned forwardly of the two connection regions 6, and to which the two connection regions 6 are integrally attached. Overall, the main region 8 and connection regions 6 together form a generally U-shaped air-bag. In the event of a collision or accident in which inflation of the pelvis restraint cushion 1 is necessary, pressurised gas is introduced into the interior of the cushion from an inflator (not shown), which may be pyrotechnic, or take any other suitable form. In known arrangements, the inflator is positioned underneath the main region 8 of the cushion 1 , and gas is introduced into the interior of the cushion 1 through an aperture, which is formed in the underside of the main region 8.

[0023] For pelvis restraint cushions of the type shown in figure 1 , it has been found to be difficult to form the cushion so that it inflates to an adequate thickness to protect the seat occupant in the manner described above. Formation of the two spaced-apart connection regions 6 reduces the overall volume of the rear region of the cushion 1 , thus limiting the thickness to which the cushion 1 can expand in the vertical direction (i.e. the direction generally perpendicular to the plane of the seat squab).

[0024] Figure 2 shows a schematic view of a first embodiment of an air-bag 9 according to the present invention.

[0025] In common with the known air-bag 1 shown in figure 1 , the air-bag 9 of figure 2 has two connection regions 6, which extend forwardly from respective rear securing points 5. An open or cut out region 7 is formed between the two connection regions 6. Towards the forward side of the air-bag 9 there is a main region 8, which extends across the entire width of the air-bag 9. The main region 8 and connection regions are preferably formed together to create a single air-bag, with a single continuous internal space.

[0026] The air-bag 9 has a front edge 10 which, in use, will lie forwardmost, i.e. overlying or in the region of the front edge of a seat squab into which the air-bag 9 is installed.

[0027] The air-bag 9 also has left and right edges 11 , 12, which in use will lie close to the left and right sides of a seat squab into which the air-bag 9 is installed, respectively.

[0028] On figure 2 a first-line marked with “A” extends across the main region 8 of the air-bag 9. A second- line, marked with “B”, extends across the two connection regions 6 of the air-bag 9.

[0029] Cut-away views of the air-bag 9, taken at the positions of the first and second lines A, B, are shown in figures 3 and 4 respectively.

[0030] Turning firstly to figure 3, at the position of the first-line the air-bag 9 has an unbroken bottom surface

[0031] 13, formed from a single region of fabric. The bottom surface 13 extends to the left and right edges 11 , 12 of the air-bag 9.

[0032] At each of the left and right edges 11 ,12, the fabric of the air-bag 9 extends inwardly to an inner fold

[0033] 14, and then extends outwardly again to reach the respective first and second edge 11 ,12. More specifically, from each side edge of the bottom surface 13, the fabric of the air-bag 9 is folded inwardly at a first edge fold 24, and a first internal layer 25 extends inwardly to the inner fold 14. A second internal layer 26 extends outwardly from the inner fold 14, to a second edge fold 27, at which it joins the top layer 16. The first and second edge folds 25, 26 are preferably aligned or substantially aligned with each other, at an edge 11 , 12 of the air-bag 9.

[0034] At each side of the air-bag 9, therefore, there is a fold or pleat 20, which extends into the air-bag 9 from the side edge 11 , 12 by a distance 15.

[0035] In preferred embodiments, at any point along the length of the air-bag 9 (i.e. in the direction extending from the rear of the air-bag 9 towards its front edge 10) the distance 15 is the same on the left side and on the right side. However, this is not essential.

[0036] In the example shown, the top surface 16 of the air-bag 9 is formed from two regions of fabric, a first 16A of which extends inwardly from the left edge 11 , and a second 16B of which extends inwardly from the right edge 12. The two regions 16A and 16B meet and overlap one another at a region near the centre of the width of the air-bag 9, and are connected together by a central seam 17.

[0037] Overall, from the cutaway view shown in figure 3, it can be seen that the main region 8 of the air-bag 9 can be formed from a single piece of fabric having opposite edges, which is folded to form the two pleats, and has the two edges joined together at the central seam 17.

[0038] Turning to figure 4, at the location of the second line B, the cut-away view of the air-bag 9 comprises two separate sections, i.e. the left connection region 6 and the right connection region 6. The open or cut-out region 7 is between these two connection regions 6. Each connection region 6 includes a bottom layer 18, which extends from an inner edge 19 of the connection region 6 towards the left or right edge 11 , 12. At the edge 11 , 12, the fabric is tucked inwardly to form a fold or pleat 20, in a similar manner to that described above in relation to figure 3. Each fold or pleat 20 extends inwardly from the respective edge 11 , 12 of the air-bag 9 by a distance 21 .

[0039] A top layer 22 of each connection region 6 extends from the left or right edge 11 , 12 to the inner edge 19.

[0040] At the inner edge 19, the bottom and top layers 18, 22 are joined together by a connection seam 23.

[0041] Returning to figure 2, the air-bag 9 also includes a front seam 28, which is formed across the front edge 10 and secures all the layers of the air-bag 9 together. The front seam 28 preferably presents an airtight or substantially airtight join between the layers of the air-bag 9. The air-bag 9 also includes a rear seam 29, which extends across the rearmost part of each connection region 6, once again joining all of the layers of the air-bag 9 together. The rear seam 29 also preferably forms an airtight or substantially air-tight seal between the layers.

[0042] Overall, the skilled reader will appreciate that the air-bag 9 has an inflatable internal region defined between the top and bottom layers 16, 22; 13, 18, and secured by the front and rear seams 28, 29, and connection seam 23. At the edges 1 1 , 12 of the air-bag 9, the fabric of the air-bag 9 is folded to form the folds or pleats 20, and the air-bag 9 is therefore sealed at its edges 1 1 , 12.

[0043] In preferred embodiments the fabric of the air-bag 9 is not completely air-tight, and allows gas to escape therethrough at a particular rate. As with many other types of air-bag, this means that, following inflation, the air-bag will deflate relatively rapidly, typically within a few seconds or less.

[0044] Also visible in figure 2 are dashed lines 30, which indicate the position of the inner fold 14 of the fold or pleat 20 that is formed on each side of the air-bag 9.

[0045] As can be seen in figure 2, in this example there is a first distance between the inner fold 14 and the respective edge 1 1 , 12 of the air-bag 9 near the rear side of each connection region 6, and a second, greater distance near the front edge 10 of the main region 8. In other words, the depth of the fold or pleat 20 is greater near the front 10 of the main region 8 than it is at the rear of each connection region 6.

[0046] In the embodiment shown in figure 2, this distance increases at a constant rate from the rear of the airbag 9 towards its front edge 10. However, this is not essential, as will be explained in more detail below.

[0047] In the event of a crash or other situation which requires inflation of the air-bag 9, pressurised gas is introduced into the interior of the air-bag 9 from one or more suitable inflators (not shown). Figure 2 shows the possible location of an inflation aperture 31 , although the invention is not limited to this. The introduction of the pressurised gas will lead to rapid inflation of the air-bag 9.

[0048] When the air-bag 9 is inflated, the depth of the air-bag 9 will increase significantly, as gas fills the internal space and drives the top and bottom layers apart from each other. As this happens, the fold or pleat 20 at each side of the air-bag 9 will unfold, and the first and second internal layers 25, 26 of each fold or pleat 20 will form side walls of the inflated air-bag.

[0049] The skilled reader will appreciate that the presence of the folds or pleats 20 at each side of the air-bag 9 will greatly increase the depth of the inflated air-bag 9, compared to a situation where these folds or pleats 20 are not provided. The additional regions of fabric which form the first and second internal layers 25, 26 allow a significantly greater distance to be created between the top and bottom layers of the airbag 9 when it is inflated. The presence of the fold or pleat 20 on each side of the air-bag 9 therefore confers significant advantages with respect to the depth of the inflated air-bag. The benefits of this, with respect to the protection of an occupant of the seat, are discussed above.

[0050] Further, the increased depth of the fold or pleat 20 - i.e. the distance between the inner fold 14 and the respective edge 1 1 , 12 of the air-bag 9 - leads to an increased depth of the inflated air-bag 9 near the front edge 10 thereof, compared to the depth of the air-bag 9 at its rear end. This will help to create a “wedge” shape for the inflated air-bag, with the thickness of the air-bag 9 being greater towards the front edge 10. Once again, this confers significant benefits with respect to protection of a seat occupant, which are discussed above.

[0051] The skilled reader will understand that the air-bag shown in figures 2-4 will be effective in protecting the occupant of a seat during a collision, particularly a head-on or rear collision.

[0052] As discussed above, in the example shown in figure 2 the depth of the pleat or fold 20 increases constantly, and in a linear manner, from the rear end of the air-bag 9 to its front edge 10. However, this is not essential.

[0053] In other embodiments, the increase in depth from the rear of the air-bag 9 to the front edge 10 may not be consistent or linear.

[0054] Figure 5 shows a further embodiment, with lines indicated by reference numeral 32 showing the depth of the fold or pleat 20 on each side of the air-bag 9. In this embodiment, the depth is at a minimum near the rear of the air-bag 9, increases relatively gradually over a first portion of the length of the air-bag 9 (which is closer to the rear part of the air-bag 9), and then increases more rapidly over a second portion of the length of the air-bag 9 (which is closer to the front edge 10 thereof).

[0055] This embodiment may have advantages, in that it can produce a wedge shape for the resulting inflated air-bag which has a relatively sharp increase in thickness near the front edge of the air-bag 9. This may have additional benefits in preventing submarining of the seat occupant.

[0056] Figure 6 shows a further embodiment, in which lines indicated by reference numeral 33 again indicate the depth of the fold or pleat 20 on each side of the air-bag 9. In this embodiment, the depth is the same, or substantially the same, over the entire length of the air-bag 9.

[0057] Embodiments of this type may be necessary where, due to other constraints arising from the construction of the seat, or through other requirements of the manufacturer, the depth of the inflated airbag should be more uniform over its length. It should be appreciated that embodiments like those shown in figure 6 will still confer significant advantages with respect to the prior art, relating to increased overall depth of the inflated air-bag.

[0058] The examples discussed above involve a single fold or pleat on each side of the air-bag, with the depth of this fold or pleat being variable over the length of the air-bag. However, in further embodiments, other techniques can be used to give rise to the required depth for the inflated air-bag.

[0059] With reference to figure 7, a further air-bag embodying the invention is shown. First lines indicated by reference numeral 34 designate the depth of a first fold or pleat that is formed at each side of the airbag. As with the example shown in figure 6, this first fold or pleat has a depth which is the same or substantially the same over the length of the air-bag.

[0060] Second lines, indicated by reference numeral 35, indicate the depth of a second fold or pleat, which is formed only in a region which is nearer the front edge of the air-bag, and is not formed in a further region towards the rear of the air-bag. This second fold or pleat lies above or below the first fold or pleat.

[0061] A cut-away view of the air-bag of figure 7, at the line indicated by B, would resemble that shown in figure 4. At this point on the length of the air-bag (which crosses the connection regions 6) there is a single fold or pleat formed at each side of the air-bag.

[0062] However, a cut-away view at the line indicated by A, which passes across the main region 8 of the airbag, is as shown in figure 8. Similar to the cutaway view of figure 3, at line A the air-bag of figure 7 has a bottom surface which extends to a first edge fold 24, from which a first internal layer 25 extends inwardly to a first inner fold 36. From the first inner fold 36 a second internal layer 26 extends outwardly to a second edge fold 27.

[0063] However, from this second edge fold 27, a third internal layer 37 extends inwardly to a second inner fold 38, from which a fourth internal layer 39 extends outwardly to a third edge fold 40. The top surface 16 of the air-bag extends inwardly from the third edge fold 40. In this example, as before, the top surface 16 is formed from two layers that are joined together at a central seam 17.

[0064] When the air-bag shown in figure 7 is inflated, the front region which has two folds or pleats will expand to have an increased depth, because the first to fourth internal layers 25, 26, 37, 39 will unfold to form side walls of the air-bag. Forming a second fold or pleat in a region at or near the front of the air-bag therefore allows the front of the air-bag to have extra depth when inflated, compared to the rear of the air-bag.

[0065] Overall, in preferred embodiments there is a fold arrangement formed on each side of the air-bag in its uninflated state. At any point, the air-bag has a top layer and a bottom later, which each have a side edge. The fold arrangement comprises a length of air-bag fabric which is positioned between the side edges of the top and bottom layers. When the air-bag is inflated, the length of fabric of the fold arrangement becomes a side wall of the air-bag, allowing a certain depth of the air-bag.

[0066] The length of fabric of each fold arrangement is preferably positioned between the top and bottom layers, i.e. within the overall footprint of the top and bottom layers.

[0067] The fold arrangement may take the form of a single pleat or fold, as is the case for the examples shown in figures 2, 5 and 6. Alternatively, at at least some points along the length of the air-bag, the fold arrangement may take the form of two or more folds or pleats, as shown in figure 7. The invention is not limited to this, however, and any suitable configuration of fold arrangement is possible.

[0068] In preferred embodiments, the fold arrangements on each side of the air-bag have a first length of fabric at a rear side of the air-bag, and a second, greater length of fabric at a front side of the air-bag.

[0069] It is also envisaged that the fold arrangements may extend over only a part of the length of the air-bag. An example of this is shown schematically in figure 9. In this figure lines indicated by reference numeral 41 show the depth of a single fold or pleat formed on each side of the air-bag. As can be seen in this figure, over a first region 42 of the length of the air-bag, closer to the rear of the air-bag, there is no fold arrangement.

[0070] The fold arrangement begins at a point 43, partway along the length of the air-bag. From this point, the depth of the fold increases over a second region 44, which is closer to the front edge 10 of the air-bag than the first region 43. The fold has a maximum depth at or near the front edge 10 of the air-bag.

[0071] The air-bags shown in all of the examples can be formed from a single piece of fabric, which is folded in a suitable way, and then joined by seams to form an enclosed internal region. While this is preferred to minimise cost and weight, and the number of processing steps to produce the air-bag, this is not essential. In other examples the air-bag can be formed from two or more separate regions of fabric which are joined together in any suitable way, for instance by sewing.

[0072] In the embodiments shown in the figures the connection regions 6 are narrowest at their rear ends, and become wider as they extend forwardly towards the main region 8. However, this is not essential, and the connection regions can take any suitable shape. In other examples the connection regions may have a generally constant width along their lengths.

[0073] With reference to figures 10-12, an alternative method of forming an air-bag similar to the air-bag 9 shown in figures 2-4 is shown.

[0074] With reference to figure 10, a first region of fabric 45 is shown. This first region 45 overlays a second, generally identical, region of fabric. The shape of the first region of fabric 45 is similar to that of the air-bag 9 shown in figure 2, having first and second connection regions 6 with a cut out region 7 therebetween, and a main region 8. However, the width of the main region 8 increases towards the front edge 10.

[0075] The two regions of fabric are sewn together along their left and right edges 1 1 , 12 by lines of stitching (which are indicated by reference numeral 46).

[0076] The two layers of fabric are also joined together around the perimeter of the cut out region 7.

[0077] Turning to figure 1 1 , as a next step the left and right edges 1 1 , 12 are tucked in, so that they lie between the two layers of fabric. In the example shown, the left and right edges 1 1 , 12 are tucked in along their lengths, so that the width of the resulting structure is generally constant along its length. As the skilled reader will understand, since the regions of fabric 45 become wider towards the front end 10, this means that the distance by which the sewn edges are tucked in increases correspondingly towards the front edge 10.

[0078] In the view shown in figure 1 1 , the location of the sewn edges is indicated by dashed lines 47.

[0079] Turning to figure 12, finally further lines of stitching 46 are formed to join the two regions of fabric together at or near the front edge 10, and at or near the securing points 5 of the connection regions 6. It will be understood that these further lines of stitching 46 will serve to retain the folded configuration of the finished air-bag 48.

[0080] Figure 13 shows a cross-section through the air-bag 48, taken along the line D-D in figure 12.

[0081] As can be seen in figure 13, at this point the cross-section of the air-bag 48 comprises a top surface, formed from the first region of fabric 45, and also a bottom surface 49 formed from the opposing second region of fabric.

[0082] Between the top and bottom surfaces there are folds 50 which protrude inwardly between the top and bottom surfaces. The lines of stitching 46 are positioned at the inner ends of these folds 50.

[0083] The skilled person will realise that constructing an air-bag in accordance with the invention may be done in many different ways, including the constructions shown in figures 2-4 and figures 10-13. The skilled person will be aware of other ways in which this may be achieved, however.

[0084] The skilled reader will appreciate that air-bags embodying the invention will confer significant advantages, with respect to known air-bags, relating to depth of the inflated air-bag, and control over the depth of the inflated air-bag over the length of the air-bag. In practice, air-bags embodying the invention may be provided as an air-bag unit, in which the air-bag is folded into a generally flat configuration to be incorporated into the squab of a vehicle seat. The airbag may be entirely or partially enclosed within a housing or cover prior to inflation. The housing or cover may be formed with one or more lines or regions which are weaker than the remaining parts, so that these regions preferentially break or rupture during inflation to allow the air-bag to assume its fully inflated configuration.

[0085] The air-bag unit may also include an inflator, along with suitable connections to allow pressurised gas generated by the inflator to be directed into the interior of the air-bag.

[0086] When used in this specification and the claims, the term “comprises” and “comprising” and variations thereof mean that specified features, steps or integers and included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

[0087] The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilized for realising the invention in diverse forms thereof.

[0088] The invention may also broadly consist in the parts, elements, steps, examples and / or features referred to or indicated in the specification individually or collectively in any and all combinations of two or more said parts, elements, steps, examples and / or features. In particular, one or more features in any of the embodiments described herein may be combined with one or more features from any other embodiment(s) described herein.

[0089] Protection may be sought for any features disclosed in any one or more published documents referenced herein in combination with the present disclosure.

[0090] Although certain example embodiments of the invention have been described, the scope of the appended claims is not intended to be limited solely to these embodiments. The claims are to be construed literally, purposively, and / or to encompass equivalents.

Claims

CLAIMS1 . An air-bag for incorporation into the squab of a vehicle seat, the air-bag comprising: a front edge, a rear edge and respective first and second side edges; an open or cut-out region at or near the rear edge; a top layer and an opposing bottom layer; and at each side of the air-bag, a fold arrangement formed between the top and bottom layers, the fold arrangement comprising a length of fabric that extends between the side edges of the top and bottom layers.

2. An air-bag according to claim 1 wherein, in a first region at or near the rear edge of the air-bag, the fabric of the fold arrangement has a first length, and at a second region near the front edge of the air-bag, the fold arrangement has a second length which is greater than the first length.

3. An air-bag according to claim 2, wherein the length of fabric of the fold arrangement increases in a linear or substantially linear manner from the first region to the second region.

4. An air-bag according to any preceding claim 1 , wherein the fold arrangement comprises, over all or some of the length between the rear edge and the front edge, a single fold, in which the length of fabric extends inwardly from the side edge to an inner fold.

5. An air-bag according to claim 4, wherein the fold arrangement comprises a single fold, in which the length of fabric extends inwardly from the side edge to an inner fold, over all or substantially all of the length between the rear edge and the front edge.

6. An air-bag according to claim 1 or 2, wherein over all or some of the length between the rear edge and the front edge, the fold arrangement comprises a double fold, in which the length of fabric of the fold arrangement extends inwardly from the side edge to two separate inner folds.

7. An air-bag according to claim 6, wherein the fold arrangement comprises a double fold over only part of the length between the rear edge and the front edge.

8. An air-bag according to claim 7, wherein over a first portion of the length of the air-bag, the fold arrangement comprises a single fold, and over a second portion of the length of the air-bag, the fold arrangement comprises a double fold, the second portion being closer to the front edge of the air-bag than the first portion.

9. An air-bag unit comprising an air-bag according to any preceding claim.

10. A squab for a seat, comprising an air-bag according to any one of claims 1 to 8 or an air-bag unit according to claim 9

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