Method of producing laminated airbag and related laminated airbag

Abstract

A method of producing a laminated airbag is disclosed. The method is particularly configured to allow batch lamination of a plurality of airbag preforms formed within an initial flexible web, and which remain connected to each other in the form of a web throughout the lamination step. The proposed method provides a more convenient way to produce laminated airbags because it does not require separate lamination of individual airbags.

Description

Technical Field

[0001] In a first aspect, the present invention relates to a method of producing a laminated airbag. In a second aspect, the present invention relates to a laminated airbag produced by the method of the first aspect. Background Art

[0002] Inflatable airbags are well known, for example, in the field of safety equipment for motor vehicles. Such airbags are typically configured to deploy via inflation upon detection of an incident such as an impact or collision to provide cushioning protection to a motor vehicle occupant or a pedestrian, cyclist or other vulnerable road user. As will be appreciated, in order to provide effective protection, it is important that such airbags inflate quickly so that they will achieve substantially complete deployment very quickly.

[0003] Inflation times vary between specific airbag types, depending on their intended function. For example, so-called inflatable curtain airbags that are arranged to deploy across the side windows in the cabin of a motor vehicle to provide protection to the vehicle occupants in the event of a rollover accident actually need to be inflated very quickly. This is because the space between the occupants of the motor vehicle and the side windows of the motor vehicle is very limited, thereby reducing the time available for the inflatable air curtain to achieve full inflation and limiting the inflation depth of the airbag. These factors combine to require that the inflatable air curtain be inflated not only very quickly relative to other types of motor vehicle airbags, but also at a particularly high pressure. Moreover, due to the potentially extended period of time for rollover-type accidents for which the inflatable air curtain is intended to provide passenger protection, the inflatable curtain airbag is required to maintain a substantially fully inflated state for a significantly longer period of time than most other types of motor vehicle airbags. Therefore, inflatable curtain airbags are generally required to have the highest pressure retention performance of any type of motor vehicle airbag. For example, a typical inflatable curtain airbag may be required to have a pressure hold value in the region of 50% of peak pressure 5 seconds after initial inflation (e.g., providing an internal pressure of approximately 20 kPa 6 seconds after initial inflation compared to a peak inflation pressure of approximately 40 kPa).

[0004] The above-described performance characteristics of inflatable curtain airbags mean that the integrity of the seams of such airbags is very important to prevent leakage of inflation gas during the period of time during which the airbag is required to remain substantially fully inflated. Accordingly, it is known to construct inflatable curtain airbags (as well as some other types of high performance motor vehicle airbags) as so-called "one-piece woven" ("OPW") airbags, in which the seams (such as the perimeter seams) of the airbag are integrally formed from the woven structure of two layers of woven fabric that define the airbag. In such OPW airbags, the inflatable chamber of the airbag is defined between a pair of fabric woven layers, and the seams of the airbag are defined by areas where the yarns of the woven fabric of one fabric layer are interwoven with the yarns of the woven fabric of another layer, so that the seams are provided as an integral feature of the woven structure of the fabric. Such a structure provides very good seam integrity.

[0005] Air bags have also been proposed for use in personal protective equipment intended to provide specific protection to a specific body part by arranging the air bag in the vicinity of the specific body part to be protected. By wearing a garment or accessory comprising a suitably configured air bag arranged at a defined position on the wearer's body, the air bag can be inflated in the event of an impending or ongoing accident, thereby providing a cushioning effect to the specific body part. For example, it has been proposed to equip the driver of a motorcycle or other motorized two-wheeled vehicle with a motorcycle protective suit (such as a jacket, trousers or full-body suit) having one or more inflatable air bags arranged to be deployed when a fall or collision is detected to provide a cushioning effect and thereby reduce the impact forces acting on the wearer's body.

[0006] It has been found that airbags for use in personal protective equipment of the general type described above (such as, for example, motorcycle protective clothing) must have even higher pressure retention performance than current motor vehicle inflatable curtain airbags. In addition, while most motor vehicle airbags (such as inflatable air curtains) are required to be deployed only once, it is desirable for personal protective equipment to incorporate airbags that can be repackaged for subsequent use after deployment. For example, in some applications, it may be considered desirable for an airbag disposed within a motorcycle protective clothing to be able to be deployed up to three times (and repackaged between such deployments) with negligible reduction in inflation performance from one deployment to the next. Each deployment will impose considerable stress on the seams of such an airbag, and therefore the seam integrity of such a personal protection airbag may be even more troublesome than for a motor vehicle inflatable curtain airbag. It is therefore believed that OPW airbags are also particularly suitable for such personal protection airbags, but in some cases further steps may be necessary to further improve the seam integrity.

[0007] It has been discovered that by laminating a fabric airbag of the general type described above (optionally including a polyurethane coating on the outer surface of each fabric layer) between a pair of film layers, such as film layers of thermoplastic polyurethane ("TPU"), wherein the two film layers are sealed to each other around the periphery of the fabric airbag, leakage of inflation gas from the airbag can be greatly reduced, thereby allowing for significant improvements in pressure retention performance, even during multiple deployments.

[0008] OPW airbags are typically woven in one piece in an elongated web comprising two fabric layers, which are woven simultaneously on a specially constructed loom. The resulting web will include a pair of woven fabric layers that are interconnected in the region defining the seams of the multiple airbags. Individual fabric airbags are then cut from the web. The resulting fabric airbag can then be laminated between the two film layers to form a laminated airbag. In order for the laminated film layers to provide an effective and secure seal around the woven perimeter seams of the airbag, it is important that the two film layers are directly sealed to each other (e.g., via an adhesive) around the outer cut edges of each fabric airbag. This can be easily achieved if the lamination step is performed on each individual fabric airbag after each individual fabric airbag is cut from the web. However, laminating multiple individual fabric airbags separately is time consuming, and therefore may be expensive and / or inconvenient, and may introduce the possibility of manufacturing inconsistencies.

[0009] The present invention is designed based on the above considerations. Summary of the invention

[0010] According to a first aspect of the present invention, a method for producing a laminated airbag is provided, the method comprising: providing a flexible web comprising a pair of superimposed woven fabric layers and having a plurality of adjacent airbag preforms formed between the fabric layers, so that each of the airbag preforms comprises a corresponding peripheral seam interconnecting the woven fabric layers and defining the periphery of the corresponding airbag preform; an initial cutting step, in which a plurality of first incisions are formed through the two fabric layers outside the periphery of each airbag preform, the incisions cooperating to jointly surround the periphery of each airbag preform except for at least one uncut connection area of ​​the flexible web located between each corresponding adjacent pair of airbag preforms; a removing step, in which the first incisions at each airbag preform are removed from the flexible web The invention further comprises a step of laminating the reduced web between two film layers to form a laminated web, wherein the film layers are directly sealed to each other around each of the airbag preforms to form a corresponding peripheral seal extending around the peripheral seam of each of the airbag preforms except at the position of the or each of the connecting regions; and a second cutting step, wherein a corresponding peripheral cut is formed through the laminated web around each peripheral seam and in the region of the corresponding peripheral seal to separate the corresponding laminated airbag from the laminated web.

[0011] Each airbag preform can be defined within the flexible web by a corresponding peripheral seam formed by an area of ​​the web in which the yarns of the woven fabric of one layer are interwoven with the yarns of the woven fabric of another layer. In such a method and arrangement, the resulting airbags will each be a so-called "one-piece woven" (OPW) airbag, having a peripheral seam integrally formed as a part of the inherent structural woven fabric of the woven fabric. Compared with more conventional seams that are sewn, glued or otherwise combined, the airbag seams formed via such one-piece weaving techniques are particularly strong, which may be advantageous for some applications. For example, the one-piece woven seams of OPW airbags can provide very high leakage resistance, which is particularly advantageous in applications where the airbag must be inflated very quickly and / or inflated to high pressure and / or must be repeatedly inflated.

[0012] Optionally, the superposed woven fabric layers are not connected to each other in the or each connection zone. By keeping the two fabric layers not connected (e.g., not interlaced) in the connection zone, then (in the embodiment where the second cutting step is included in cutting through the fabric in the connection zone) the peripheral incision can be more easily formed in the second cutting step.

[0013] At least a portion of each first cut formed in the initial cutting step may be adjacent to the periphery of the airbag preform but spaced outwardly from the periphery of the airbag preform. In this way, each first cut will be positioned to leave the periphery seam of each airbag preform, thereby retaining the structural integrity of the periphery seam of the resulting airbag.

[0014] Optionally, each first cut formed in the initial cutting step is looped to define a respective area of ​​each fabric layer for removal from the flexible web in the removal step, thereby defining a respective window in the reduced web. By forming looped cuts that define respective windows in the reduced web, the area of ​​fabric removed from the flexible web can be reduced, thereby leaving a larger area of ​​fabric in the reduced web. This can help improve handling of the reduced web, for example by making it easier to wind onto or into a roll in a subsequent step of the process.

[0015] The initial cutting step may provide a plurality of said connection regions at spaced locations around the perimeter of each air bag preform, each connection region being defined between an adjacent pair of windows in the reduced web.

[0016] In embodiments where windows are created in the reduced web, the laminating step may include sealing the film layers directly to each other through each window formed in the reduced web.

[0017] Optionally, the initial cutting step comprises forming the first cut through two layers of woven fabric simultaneously.This simplifies the cutting step and ensures that the first cut formed through the two layers of fabric is accurately aligned, which in turn helps to define a consistent edge to the fabric, thereby defining a corresponding air bag.

[0018] The peripheral cuts formed in the second cutting step can each be formed in a spaced relationship with the corresponding peripheral seam and outside the peripheral seam. This ensures that sufficient width of the peripheral seal (i.e., the area where the two film layers are sealed to each other) will remain around the peripheral seam of each fabric airbag to ensure a good seal around the seam.

[0019] In a preferred embodiment, it is contemplated that the cuts made during the first and / or second cutting steps will be made via laser cutting.

[0020] Optionally, each peripheral incision extends through the or each connection area, thereby dividing the or each connection area. Preferably, each connection area will be narrow (as considered along the path of the peripheral incision), so that the interruption in the peripheral seal portion caused by the surrounding connection area will be small. This helps to minimize the leakage of inflation gas through the peripheral seal portion when the airbag is inflated. In an embodiment in which the peripheral incision is formed via laser cutting, the power and / or speed of the laser when the laser cuts through the or each connection area can be adjusted relative to the power and / or speed used when the laser cuts through the laminated peripheral seal portion. For example, the power of the laser can be increased and / or the speed at which the laser moves through the laminated web can be reduced during the laser cutting through the or each connection area relative to the power / speed of the laser during cutting through other areas of the laminated peripheral seal portion.

[0021] Optionally, the method further comprises a winding step in which the reduced web is wound onto or into a roll, the winding step being performed between the removal step and the lamination step. This is facilitated by the connection region, which is used to interconnect the airbag preforms in the reduced web. The integrity of the reduced web is thus retained, thereby allowing it to be wound onto or into a roll for easier handling and / or movement and / or storage before the subsequent lamination step of the process. In this way, the plurality of airbag preforms remain as part of a flexible web that can subsequently be laminated as a whole, rather than having to separately laminate discrete airbag preforms. This allows a plurality of airbag preforms to be laminated in a batch process rather than one by one.

[0022] Optionally, the method further comprises a winding step in which the laminated web is wound onto or into a roll, said winding step being performed between the laminating step and the second cutting step. Again, this allows easier handling and / or movement and / or storage of the laminated web (comprising a plurality of laminated airbag preforms) prior to the subsequent second cutting step in which the respective final laminated airbags are separated from the web.

[0023] Preferably, i) the flexible web is coated with a coating on at least one side prior to said initial cutting step, or ii) the reduced web is coated with a coating on at least one side prior to said laminating step. In preferred embodiments, it is contemplated that the coating may comprise polyurethane. The coating may be applied to both sides of the flexible web or the reduced web.

[0024] The laminating step may include laminating the reduced web between two film layers of thermoplastic polyurethane ("TPU").

[0025] According to a second aspect of the present invention, a laminated airbag produced according to the method of the first aspect is provided. In some embodiments, the airbag may be characterized in that it includes a pair of overlapping woven fabric layers defining an inflatable chamber therebetween, the two fabric layers interconnected around the periphery of the airbag to define a peripheral seam, and wherein the overlapping fabric layers are laminated between a pair of film layers, the film layers are sealed to each other to define a peripheral seal extending around the outside of the peripheral seam. The peripheral seal may extend substantially completely around the peripheral seam, except for the area retaining the remainder of the connection area. In some embodiments, the peripheral seam of the airbag may be formed by an area where the yarns of the woven fabric of one of the fabric layers are interwoven with the yarns of the woven fabric of another of the fabric layers. The fabric layer may include a coating (e.g., a polyurethane coating) on ​​its outwardly facing surface. The film layer may be formed by thermoplastic polyurethane ("TPU"). BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order that the present invention may be more readily understood and in order that further features thereof may be appreciated, embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0027] Figure 1 is a schematic diagram showing a flexible web including a pair of stacked fabric layers and a plurality of airbag preforms;

[0028] Figure 2 is similar to Figure 1 Schematic diagram of , but showing a region of the flexible web after an initial cutting step;

[0029] Figure 3 is shown after the cutting step Figure 2 Schematic diagram of further detail of an enlarged area of ​​the web depicted in FIG.

[0030] Figure 4 is similar to Figure 2 , but showing a reduced web formed from a flexible web after a subsequent removal step;

[0031] Figure 5 is similar to Figure 4 , but showing a laminated web formed from the reduced web after a subsequent lamination step;

[0032] Figure 6 is a schematic diagram showing an enlarged area of ​​a laminated web after a second cutting step;

[0033] Figure 7 is similar to Figure 4 Schematic diagram of , but showing an alternative form of the reduced web formed after an alternative cutting and removing step;

[0034] Figure 8 is shown after the subsequent lamination step from Figure 7 A schematic diagram of a laminated web formed by a reduced web;

[0035] Fig. 9 It is shown Figure 8 A schematic diagram of further detail of an enlarged area of ​​the laminate web shown in ;

[0036] Fig.10 is shown after the second cutting step Figure 8 A schematic diagram of a laminated web of

[0037] Fig.11 is a schematic diagram showing more detail of an enlarged area of ​​the laminate web shown after the second cutting step. DETAILED DESCRIPTION

[0038] Various aspects and embodiments of the present invention will now be discussed with reference to the accompanying drawings. Additional aspects and embodiments will be apparent to those skilled in the art.

[0039] First look Figure 1 , shows a length region of an elongated flexible web 1 comprising a pair of superposed woven fabric layers 2, 3. The two fabric layers 2, 3 are woven on a specially constructed loom (of a type known per se) from warp yarns 4 and weft yarns 5 (in Figure 1 2, 3) are woven simultaneously. Over the main area of ​​the web 1, the two fabric layers 2, 3 are formed to be different and separate from each other and are therefore not connected. However, in a predetermined area of ​​the web 1, the yarns 4, 5 of the two layers 2, 3 are interwoven to define the seams of a plurality of airbag preforms 6. Each airbag preform 6 is thus confined within the flexible web 1 to be formed between the two fabric layers 2, 3 and includes at least a peripheral seam 7 that interconnects the fabric layers and defines their periphery. The peripheral seam 7 (and optionally also one or more internal seams 8) of each airbag preform 6 is thus formed by an area of ​​the flexible web in which the yarns 4, 5 of the woven fabric of one fabric layer 2 are interwoven with the yarns 4, 5 of the woven fabric of another fabric layer 3, for example via a so-called one-piece weaving technique. An exemplary one-piece weaving technique is described in more detail in International Patent Publication WO199009295A.

[0040] As will be observed, the airbag preforms 6 are each arranged along Figure 1 The longitudinal length of the flexible web 1 is shown aligned. However, it should be understood that the airbag preforms 6 can be distributed differently within the flexible web 6, for example to more efficiently utilize the area of ​​the web. However, an important aspect is that the airbag preforms 6 are all spaced apart from each other within the web 1.

[0041] In the specific embodiment shown, each of the airbag preforms 6 is provided in a shape and configuration suitable for producing a finished laminated airbag for installation in a garment such as a jacket or suit to provide protection to the torso and upper body of a wearer (e.g., a motorcyclist). Each airbag preform 6 thus includes a pair of chest portions 9, a pair of shoulder regions 10 (each shoulder region includes three "wings" to facilitate deployment around the curve of the occupant's shoulders) and a pair of back portions 11. As will be seen, a central opening 12 is defined by the peripheral seam 7, which will accommodate the neck of the wearer in the finished airbag. Each airbag preform 6 also includes a pair of inlet sections 13, which will define an inlet channel for receiving inflation gas, such as from an inflator incorporated into the garment. However, it should be understood that the present invention is not limited to providing this particular type of airbag and may alternatively be implemented in the production of other types of airbags. In addition, all airbag preforms 6 disposed in a single flexible web 1 do not have to be of the same type or have the same configuration. Therefore, a single elongated flexible web 1 may include a plurality of airbag preforms 6 of different configurations.

[0042] After weaving, the flexible web 1 may be coated with a thin surface coating of polyurethane. The polyurethane coating may be applied by spraying techniques and is preferably applied to both sides of the flexible web 1.

[0043] Figure 2 1 shows a subsequent stage in the method of the invention and shows a region of the flexible web 1 after an initial cutting step. For example, a plurality of first cuts 14 are made simultaneously through the two fabric layers 2, 3, for example by laser cutting techniques. Figure 2 As shown, the first cutouts 14 are formed outside the perimeter of each airbag preform 6 defined by the perimeter seam 7. It should also be understood that the first cutouts 14 can be formed adjacent to the perimeter of each airbag preform 6 but spaced outwardly from the perimeter of each airbag preform 6 (e.g., approximately 1 cm), and can generally follow the shape of the perimeter seam 7. However, some of the first cutouts 14 can be configured so that they can have an area that is slightly more spaced from the perimeter seam 7, such as to define a fabric mounting tab for the finished airbag - such as Figure 2 As shown in 15.

[0044] Figure 3 An enlarged area of ​​the flexible web 1 after the initial cutting step is shown (at Figure 2 1 and 2 ), and particularly shows the construction of a first cut 14 formed in the region between a pair of adjacent airbag preforms 6. The first cut 14 is constructed to surround the periphery of each airbag preform 6 together, except for a pair of (in this embodiment) uncut connection areas 16 of the flexible material sheet 1 located between the pair of adjacent airbag preforms 6. Figure 3A very narrow uncut connection area 16 is shown (eg 5 mm in width measured in the weft direction of the flexible web 1 ), but in other embodiments the uncut connection area 16 may be wider (eg up to 50 mm in width in the weft direction).

[0045] After the initial cutting step described above, a removal step follows in which the Figure 2 and Figure 3 The flexible web 1 shown has regions of the two textile layers 2 , 3 removed outside the periphery of each airbag preform 6 , and these regions are separated by a first cut 14 . Figure 4 represents the result of the removal step, and specifically shows that by removing Figure 2 1 . As will be appreciated, large side areas of the fabric layers 2, 3 are removed from the flexible web. Figure 3 1, it will be appreciated that the area of ​​each fabric layer 2, 3 between two adjacent airbag preforms 6 and between two uncut connection areas 16 is also removed. As will be appreciated, all of the outer fabric outside the airbag preform 6 is thus removed from the flexible web 1, except for the narrow area extending around the periphery of the airbag preform 6 and the uncut connection areas 16 between adjacent airbag preforms 6. However, the airbag preforms 16 remain interconnected by the connection areas 16 extending between adjacent airbag preforms 6, and therefore, the reduced web 17 remains attached. Therefore, after the above-mentioned removal step, the reduced web 17 can be rolled onto or into a roll.

[0046] As will be understood, Figure 2 The reduced web 17 shown has a reduced width in the weft direction compared to the initial flexible web 1 shown in FIG. As will also be understood, because the fabric layers 2, 3 of the initial flexible web 1 are separated from each other except where they are interwoven to define the seams 7, 8 of the airbag preform 6, the edge regions and also the connection regions 16 of the resulting reduced web 17 each comprise two layers of unconnected fabric.

[0047] Where the flexible web 1 is not coated with polyurethane prior to the initial cutting step, the reduced web 17 may be coated with a thin surface coating of polyurethane after the above cutting and removal steps. The polyurethane coating may be applied by spraying techniques and is preferably applied to both sides of the reduced web 17.

[0048] The reduced web 17 may then be laminated as a whole between two film layers 18, 19 to form a laminate web 20, such as Figure 5Schematically shown in FIG. The film layers 18, 19 are preferably formed of thermoplastic polyurethane (TPU). As will be noted, the film layers 18, 19 have a width greater than the width of the reduced web 17, so that during the lamination step, the reduced web 17 is received in its entirety between the film layers 18, 19. The two film layers 18, 19 are directly sealed to each other in all areas where they are in contact with each other, thereby forming a peripheral seal 21 extending around the peripheral seam 7 of each airbag preform 6, except at the location of the connection area 16.

[0049] The laminate web 20 may then be rolled onto or into a roll prior to subsequent steps in the process.

[0050] After the above-mentioned lamination step, the laminated web 20 is subjected to a second cutting step in which a peripheral cut 22 is formed through the laminated web 20. Figure 6 This is most clearly shown in Figure 6 An enlarged area of ​​the laminate web 20 between adjacent airbag preforms 6 is shown (in Figure 5 Each peripheral cutout 22 extends around the outer side of the peripheral seam 7 of the corresponding airbag preform 6 . Figure 6 Thus, parts of two such peripheral cutouts 22 are shown - an uppermost peripheral cutout 22' extending around a first airbag preform 6 and a peripheral cutout 22' extending around a second ( Figure 6 The peripheral cuts 22 are each formed in a spaced relationship with and outside the corresponding peripheral seam 7. Preferably, the peripheral cuts 22 will generally follow the shape of the peripheral seam 7, or alternatively (at least in some areas, such as the mounting tab area 15) may follow the shape of the first cut 14 around the airbag preform 6. It is proposed that the peripheral cuts 22 may be spaced approximately 1 cm from the initial cut 14 (now defining the edge of the fabric).

[0051] like Figure 6 As shown, the peripheral cutouts 22 extend through the connection areas 16 used to interconnect the airbag preforms 6 in the web during the previous lamination step. The peripheral cutouts 22 thus separate the connection areas 16, thereby separating the airbag preforms 6 from each other and thus providing discrete laminated airbags.

[0052] Each resulting laminated airbag will be understood to have a peripheral edge seal 23 defined by the sealing film layers 18, 19 around the outside of its peripheral seam 7. The peripheral edge seal 23 will extend around the entire periphery of the finished airbag, except where the remainder of the connection area 16 is located. At these locations, the remainder of the connection area 16 will extend across the edge seal 23 of the airbag and may optionally be sealed by a post-production step, which may, for example, include bonding the two fabric layers of the remainder of the connection area to each other.

[0053] Now turn to consider Figures 7 to 11 , an alternative method for implementing the present invention will be described. This method is similar to the above reference Figures 1 to 10 The described methods share several steps and features, therefore the same or similar steps and features are not described in detail again, and the same reference numerals are used to denote corresponding features.

[0054] Figure 7 is similar to Figure 2 , but it shows an alternative way of forming the first cuts 14 through the fabric layers 2, 3 of the initial flexible material 1. In this embodiment, each first cut 14 is looped to define a corresponding area 24 of each fabric layer 2, 3. It will therefore be seen that each first cut 14 follows a continuous path around the corresponding area 24. However, each loop first cut 14 is also formed outside the periphery of the airbag preform 6 defined by the peripheral seam 7, and has an area that generally follows the shape of the peripheral seam. And the loop first cuts 14 also surround the periphery of each airbag preform 6 together. The loop first cuts 14 are arranged at spaced positions around the periphery of each airbag preform 6, thereby defining an uncut connection area 16 (similar to those uncut connection areas of the previous embodiment) between each adjacent pair of loop cuts 14.

[0055] After forming the loop first cut 14 in the manner described above, the defined area 24 of the fabric layers 2, 3 is then removed from the flexible web 1 to form a reduced web 17 including the corresponding window defined by the loop first cut 14. As will be appreciated, because in this embodiment the area of ​​fabric 2, 3 removed from the flexible web 1 is limited to the area defined by the loop first cut 14, the resulting reduced web 17 is more compact than the previous embodiments (such as Figure 4 The reduced material 17 (shown) retains significantly more fabric. In fact, from Figure 7 As will be seen in the figure, the reduced web 17 retains the same width (in the weft direction) as the flexible web 1 from which it is formed. This retention of more fabric in the reduced web 17 makes the reduced web 17 easier to handle as it will retain more integrity. For example, Figure 7 The reduced web 17 can be more easily rolled into or onto a roll.

[0056] The reduced web 17 may then be laminated between two film layers 18, 19 to form a laminate web 20, such as Figure 8 Schematically shown in . Again, the film layers are preferably formed of thermoplastic polyurethane (TPU). As will be noted, in this embodiment, the film layers 18, 19 may have a width slightly less than the width of the reduction sheet 17. However, the film layers 18, 19 should be wide enough to cover all of the windows defined within the loop cutout 14. As will be appreciated, the two film layers 18, 19 will therefore contact each other through each window in the reduction sheet 17, and thus be sealed to each other in those areas, as shown in FIG. Fig. 9 As schematically shown in Fig. 9 An enlarged area of ​​the laminate web 20 is shown (at Figure 8 denoted C in the figure). The resulting sealed areas of the film layers 18 , 19 thus cooperate to jointly form a peripheral seal 21 extending around the peripheral seam 7 of each airbag preform 6 , also except at the location of each connection area 16 .

[0057] The laminate web 20 may then be rolled onto or into a roll prior to subsequent steps in the process.

[0058] After the above-mentioned lamination step, the laminated web 20 is subjected to a second cutting step in which a peripheral cut 22 is formed through the laminated web 20. Fig.10 in and Fig.11 This is most clearly shown in Fig.11 An enlarged area of ​​the laminate web 20 is shown (at Fig.10 The peripheral cutout 22 extends around the outside of the peripheral seam 7 of the airbag preform 6 in a spaced relationship therewith. Fig.10 and Fig.11 As shown, the peripheral cut 22 generally follows the shape of the peripheral seam 7. It should be noted that the peripheral cut 22 follows a path extending along and within the window through which the film layers 18, 19 are sealed together. However, between adjacent windows, the peripheral cut 22 extends through the connection area 16. The peripheral cut 22 thus separates the connection area 16, thereby separating the airbag preforms 6 from each other and from the laminate web 20, and thus providing discrete laminated airbags.

[0059] Therefore, as will be understood, from the above reference Figures 7 to 11Each laminated airbag resulting from the described alternative method will likewise be understood to have a peripheral edge seal defined by the sealing film layers 18, 19 around the outside of its peripheral seam 7. The peripheral edge seal will extend around the entire periphery of the finished airbag, except where the remainder of the connection area 16 is located. At these locations, the remainder of the connection area 16 will extend across the edge seal of the airbag and may optionally be sealed by a post-production step which may, for example, include bonding the two fabric layers of the remainder of the connection area to each other.

[0060] It is contemplated that in variations of both of the above methods, the initial flexible web 1 may be woven such that the area of ​​the fabric layers 2, 3 that will define the connection area 16 may have a slightly different weave structure (i.e., warp / yarn pattern) than the rest of the flexible web. For example, it is contemplated that the area of ​​the fabric layers 2, 3 that will define the connection area 16 may be specifically woven to have a surface finish that is optimized for adhesion to the respective film layers 18, 19. This may help improve the sealing effect at the remainder of the connection area 16 where the edge seal 23 of the finished airbag is interrupted.

[0061] The features disclosed in the foregoing detailed description or in the appended claims or in the drawings, expressed in their specific form or according to means for performing the disclosed functions or methods or processes for obtaining the disclosed results, may, where appropriate, be used alone or in any combination of such features to implement the invention in various forms.

[0062] Although the present invention has been described in conjunction with the above exemplary embodiments, many equivalent modifications and variations will be apparent to those skilled in the art when this disclosure is given. Therefore, the exemplary embodiments of the present invention set forth above are considered to be illustrative and not restrictive. Various changes may be made to the described embodiments without departing from the scope of the present invention.

[0063] For the avoidance of any doubt, any theoretical explanations provided herein are intended to enhance the reader's understanding. The inventors do not wish to be bound by any of these theoretical explanations.

[0064] Any section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.

[0065] Throughout this specification, including the following claims, unless the context requires otherwise, the words "have", "comprise" and "include" and variations such as "having", "comprises", "comprising" and "including" will be understood to imply the inclusion of stated integers or steps or groups of integers or steps but not the exclusion of any other integers or steps or groups of integers or steps.

[0066] It must be noted that, as used in the specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from "about" one particular value and / or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when a value is expressed as an approximation by using the antecedent "about", it should be understood that the particular value forms another embodiment. The term "about" in relation to a numerical value is optional and means, for example, + / - 10%.

[0067] The words "preferred" and "preferably" used herein refer to embodiments of the present invention that may provide certain benefits in some circumstances. However, it should be understood that other embodiments may also be preferred under the same or different circumstances. Therefore, the statement 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 scope of the claims.

Claims

1. A method for producing a laminated airbag, the method comprising: A flexible web (1) is provided, the flexible web (1) comprising a pair of superposed woven fabric layers (2, 3) and having a plurality of adjacent airbag preforms (6) formed between the fabric layers (2, 3), such that each of the airbag preforms (6) comprises a respective peripheral seam (7) interconnecting the woven fabric layers (2, 3) and defining a periphery of the respective airbag preform (6); an initial cutting step, in which a plurality of first cuts (14) are formed through the two fabric layers (2, 3) outside the periphery of each airbag preform (6), the cuts (14) cooperating to collectively surround the periphery of each airbag preform (6) except for at least one uncut connection area (16) of the flexible sheet (1) between each corresponding adjacent pair of airbag preforms (6); a removal step in which regions of the fabric layers (2, 3) outside the periphery of each airbag preform (6) and separated by the cutouts (14) are removed from the flexible web (1) to form a reduced web (17) in which the airbag preforms (6) remain interconnected via the or each connecting region (16); a lamination step in which the reduced web (17) is laminated between two film layers (18, 19) to form a laminated web (20), wherein the film layers (18, 19) are directly sealed to each other around each of the airbag preforms (6) to form a respective peripheral seal (21) extending around the peripheral seam (7) of each of the airbag preforms (6), except at the location of the or each connecting region (16); and A second cutting step, in which a respective peripheral cut (22) is made through the laminate web (20) around each peripheral seam (7) and in the region of the respective peripheral seal (21), thereby separating the respective laminate airbag from the laminate web (20).

2. A method according to claim 1, wherein each of the airbag preforms (6) is defined within the flexible sheet (1) by a corresponding peripheral seam (7), the peripheral seam (7) being formed by an area of ​​the sheet (1) in which the yarns (4, 5) of the woven fabric of one layer (2) are interwoven with the yarns (4, 5) of the woven fabric of another layer (3).

3. A method according to claim 1 or claim 2, wherein the superposed woven fabric layers (2, 3) are not connected to each other in the or each connection region (16).

4. A method according to any preceding claim, wherein at least a portion of each first cut (14) made in the initial cutting step is adjacent to but spaced outwardly from the periphery of the airbag preform (6).

5. A method according to any preceding claim, wherein each of the first cuts (14) formed in the initial cutting step is circumferential so as to define a corresponding area (24) of each of the fabric layers (2, 3) for removal from the flexible sheet (1) in the removing step, thereby defining a corresponding window in the reduced sheet (17).

6. A method according to claim 5, wherein the initial cutting step provides a plurality of the connection areas (16) at spaced locations around the periphery of each of the airbag preforms (6), each of the connection areas (16) being defined between an adjacent pair of the windows in the reduced sheet (17).

7. A method according to claim 5 or claim 6, wherein the laminating step comprises sealing the film layers (18, 19) directly to each other through each of the windows formed in the reduced web (17).

8. A method according to any preceding claim, wherein the initial cutting step comprises making the first cut (14) through two layers of woven fabric (2, 3) simultaneously.

9. A method according to any preceding claim, wherein the peripheral cuts (22) formed in the second cutting step are each formed in a spaced relationship from and outside the respective peripheral seam (7).

10. A method according to any preceding claim, wherein each said peripheral cut (22) extends through the or each said connection region (16) thereby dividing the or each said connection region (16).

11. A method according to any preceding claim, further comprising a winding step in which the reduced web (17) is wound onto or into a roll, the winding step being performed between the removing step and the laminating step.

12. A method according to any preceding claim, further comprising a winding step in which the laminate web (20) is wound onto or into a roll, the winding step being performed between the laminating step and the second cutting step.

13. A method according to any preceding claim, wherein: i) the flexible web (1) is coated on at least one side with a coating prior to the initial cutting step, or ii) the reduced web (17) is coated on at least one side with a coating prior to the lamination step, wherein the coating optionally comprises polyurethane.

14. A method according to any preceding claim, wherein the laminating step comprises laminating the reduced web (17) between two film layers (18, 19) of thermoplastic polyurethane ("TPU").

15. A laminate airbag produced according to the method of any preceding claim.

Images