MXPA99007153A - Woven airbag with flow barriers - Google Patents

Abstract

An inflatable airbag cushion (110) includes a face portion and a rear portion formed from first and second fabric layers. The cushion (110) further includes a number of straight line woven in joints (16) defining flow barrier elements (14). The flow barrier elements (14) serve to contain the inflation gases and to restrict inflation of the cushion (110).

Description

"WOVEN AIR BAG WITH FLOW BARRIERS" TECHNICAL FIELD The present invention relates to an inflatable cushion and more particularly, to a safety device for use in a motor vehicle. The present invention is particularly useful in an application as an inflatable side curtain to be placed between a vehicle occupant and the vehicle frame during a rollover event.

ANTECEDENTS OF THE TECHNIQUE Inflatable protective cushions used in passenger vehicles are a component of a relatively complex system. The main elements of this system are: a shock detection system, an ignition system, a gas producing device, a fixing device, a system enclosure and an inflatable protective cushion. Upon detecting a shock, the gas is released causing an explosive release of gas that fills the cushion to a deflated state that can cushion the shock of forward movement of a body. These cushions were initially used to protect the operator of a vehicle and were stored inside the steering column for this purpose. These driver's side cushions are described in U.S. Patent No. 5,533,755 issued to Nelsen et al. (Incorporated by reference). The cushions for the protection of the passengers of the vehicle have obtained acceptance and are typically stored in the dashboard in relation opposite to the passenger seat. Recently, the use of cushions for the protection of drivers and occupants in side impact collisions has gained general acceptance. A cushion configuration to be used in the protection of vehicle occupants during a side impact collision is the so-called side cushion configuration which is stored in the roof line and which is connected along the door frame. One embodiment of this side curtain is illustrated and described in U.S. Patent No. 5,788,270 issued to HAland et al., The teachings of which are incorporated herein by reference. As explained in the HAland et al patent, one of the objects of the side curtain configuration is to remain inflated for a relatively long period of time in order to provide protection to the vehicle occupants in the event of a rollover event. In this way, unlike the traditional side cushions for the driver and passenger who must deflate quickly during the crash by the occupant to be protected, the side curtain must remain inflated in order to be effective. Accordingly, the uncontrolled or excessive release of the inflation medium through the seams or other connecting links within the curtain is undesirable, of course. In addition to the need to control the inflation of the side curtain, it is also necessary that the curtain be of a configuration in such a way as to provide considerable protection through an extremely large area during its operation. As an example only, it may be necessary to cover the entire length of the passenger compartment to protect both the driver and any passengers seated in the rear, simultaneously in a crash. As will be appreciated, in order for the side curtain to perform its function, its configuration must be such as to provide an effective expanded profile while at the same time providing rapid efficient channeling of the inflation medium to all areas of the cushion that will inflate. In order to achieve these aims, the side cushions such as those described in the HAland patent and others, have been configured in order to have a relatively thin profile of approximately 30 to 40 millimeters during inflation. This thin profile is achieved by interlocking the fabrics that form the front and back of the curtain at selected locations during the formation of the curtain on a jacquard loom. The interlacing technique that is used by HAland is described in detail in International Patent Publication Number O / 90/09295 which corresponds to US Pat. Number 5, 685, 347 Graham et al., The teachings of which are incorporated herein by reference. As disclosed in the Graham patent, interlacing and consistent control of the shape of the airbag can be effected through the use of a loom having programming means such as a jacquard system. However, the use of these jacquard systems introduces a high level of complexity in the training process. As will be appreciated by those skilled in the art, a jacquard system utilizes a complex computer controlled process or a series of punched cards wherein each card perforation controls the action of a single warp yarn for the passage of a single pit. . A separate card is used for each bite in a certain pattern. In addition to the basic complexity, jacquard tissue also has the inherent deficiency and limitation of relying on relatively expensive equipment. In view of the above, it will be appreciated that there is a need for a side curtain configuration that can be formed on a non-jacquard loom and an efficient method for producing it. Accordingly, the present invention represents a useful advance in relation to the prior art known state.

EXHIBITION OF THE INVENTION A basic object of the present invention is to provide an essentially non-sewn inflatable curtain of non-jacquard construction preferably of fabric suitable for use as a side curtain in a transport vehicle. A further object of the present invention is to provide a bag of a non-stitched construction of machine weave suitable for use as a side curtain shock protection cushion in a transport vehicle that retains gas pressure for a prolonged period of time. after inflation. In one aspect of the present invention, an inflatable air bag cushion is provided. The cushion is in the shape of an unsecured construction bag of machine weave. The bag includes a face portion and a back portion whose face and back portions are formed of first and second fabric layers. The fabric layers are woven simultaneously in the same loom according to the controlled fabric patterns by the manipulation of warp harnesses. Each of the fabric layers is defined by a multiplicity of warp yarns running in the warp direction interposed by a multiplicity of weft yarns running in the weft direction that is essentially transverse to the warp direction. In order to keep the bag in a relatively flat condition once it has been inflated, and to channel the inflation gases through the structure, the bag includes a multiplicity of tissues in joints. These gasket fabrics are placed in order to define connection joints and flow barriers between the face portion and the back portion of the bag such that during the introduction of a gas flow into the bag, the expansion is limited by the fabric in the joints thus channeling the gas to locations where inflation is desirable while simultaneously restricting the inflation of the bag in locations where these fabrics are present in the joints. At least a portion of the fabrics in the joints preferably extend in essentially straight lines both in the warp direction and in the weft direction. In accordance with another aspect of the present invention, there is provided a method for forming the bag for a side curtain protective cushion by weaving on a loom weaving loom whereby the straight line fabric patterns are repeated across the width of the fabric. loom in order to simultaneously form two layers of fabric with fabrics in the joints placed in selected locations across the length and width of the fabric, thereby defining the interconnections between the fabric layers. The additional objects and advantages of the invention will be pointed out in the description given below and in part will be evident from the description, or can be learned by practicing the invention. It should be understood that both the foregoing general description and the following detailed description are exemplary and for explanation only and in no way should be construed as constituting restrictions on the scope of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings that are incorporated and that constitute a part of this specification, illustrate various embodiments of the invention and together with the description serve to explain the principles of the invention. In these drawings and in the accompanying description, the term "face" portion is intended to designate the surface of the protective cushion that is intended to be in contact with the person to be protected. The term "after" is meant to refer to the surface of the cushion in contact with the transport vehicle during a crash event. Figure 1 illustrates a face portion of a cushion embodiment inflatable restriction formed in accordance with the present invention. Figure 2 illustrates the face portion of an embodiment of an inflatable restriction cushion formed in accordance with the present invention. Figure 3A illustrates a possible arrangement for a production of the loom of the inflatable restriction cushion as illustrated in Figure 2. Figure 3B illustrates a possible arrangement for the production in the loom of tubular structures having interwoven seams that seal the edges to along the warp direction.

Figures 4A-4D illustrate the four basic weaving patterns used in the formation of the bag in accordance with the preferred practice of the present invention. Figure 5 illustrates a potentially preferred embodiment of a gasket fabric extending along the warp direction of the inflatable restriction cushion in accordance with the present invention. Figure 6 illustrates a potentially preferred embodiment of a gasket fabric extending along the weft direction of the inflatable restriction cushion in accordance with the present invention. Figure 7 illustrates an exemplary fabric in seams that is formed across the surface of a fabric in accordance with the present invention. Figure 8 illustrates a bag of knitting fabric in accordance with the present invention that includes a multiplicity of vertical line connections formed by the fabric in seams extending through the interior of the bag. Figure 9 illustrates a bag in accordance with the present invention that includes a multiplicity of essentially spiky connections formed by short fabric in seams extending between the face and the back of the bag.

Figure 10 illustrates a horizontal and vertical interwoven connection arrangement extending through the interior of the restriction cushion in accordance with the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Referring now to the drawings and in particular to Figure 1 thereof, there is illustrated a non-stitched cushion generally designated by the reference number 10. As illustrated, the unstressed cushion 10 includes an opening 12 for introduction of a means of inflation in the interior. In the illustrated embodiment, positioned across the interior and along the perimeter of the cushion 10, there is a plurality of flow barrier elements 14. In the potentially preferred embodiment, these flow barrier elements 14 are formed by combinations of fabric in 16 joints that are placed in both directions of the fabric. That is, a portion of the fabric in joints of preference is placed in the vertical direction while a second portion of the fabric in joints is preferably placed in the horizontal direction. For purposes of disclosure, a second configuration of flow barrier elements for a cushion configuration 110 is illustrated in Figure 2 wherein each of the barrier elements 14 includes an extended box configuration 20 positioned adjacent to the shore portion. top of the cushion. These extended box configurations are believed to be useful for channeling the inflation medium through an extended-length cushion such as may be used in the side curtain application. As illustrated, the extended box configuration preferably includes a stepped corner profile to have two or more corners to distribute the inflation effort more evenly at these locations. It will be appreciated that while only a small number of flow barrier elements are illustrated, the presence of these elements can be duplicated numerous times throughout the length of the cushion. Furthermore, even though these flow barrier elements are illustrated as extending almost to the lower edge portion of the cushion 10, 110 it is also proposed that these elements may be in the form of islands or a series of islands that do not come into contact with the upper and lower edges of the structure of the bag. Finally, even though only the front surface of the cushion according to the present invention has been illustrated, it will be appreciated that the back side of the cushion has the same configuration.

As illustrated, in the potentially preferred embodiment, the fabric at the seams forming the flow barrier elements 14 are of essentially straight line configuration. It has been found that even relatively complicated geometries, such as those illustrated in Figure 2, can be formed at the point of the fabric of the fabric by controlling a small number of fabric harnesses, without the need to use an essentially more complicated and costly jacquard fabric system. By way of example only, it has been found that knitting machines with thirty-six or smaller number of harnesses are suitable for making even very complex structures. The structure shown in Figure 2 can be manufactured on a loom of 20 harnesses or a smaller number thereof. In accordance with the practice of the present invention, two layers of woven fabrics 24 are formed simultaneously (Figure 3A) on a loom that feeds the weft yarns between a plurality of warp yarns by well-known insertion means, such as jet streams. air, water jets or projectiles, while intermittently raising and lowering the plane of the warp yarns with respect to the path of the weft yarns, so as to form an interwoven structure, as it is well known to those persons experts in the art. This fabric is described, for example, in U.S. Patent Number 5,421,378 issued to Bower et al., The teachings of which are incorporated herein by reference. By way of further explanation, two different layers of fabric can be formed on the same loom simultaneously by threading the harnesses of the loom with two sets of warp threads and alternating the opening between the two sets of warp threads as each stitch is inserted ( that is, weft thread). The joints between the two layers of fabric can be formed both in the warp direction and in the weft direction by threads crossed from one layer to the other, as will be more fully described below. In potentially preferred practice, a gasket running in the warp direction may be formed by moving the weft yarns from the upper fabric layer to the lower layer, while a gasket may be formed in the weft direction by crossing the warp yarns. Since looms controlled by machine sheave are provided with multiple harnesses, it is possible to form multiple seams across the full width and length of the fabric. Combining these joints allows complex tissue patterns to develop. A potential project for the formation of loom pockets including barrier element configurations is illustrated in Figure 3A, as illustrated in Figure 2. It will be appreciated that each joint constituting the flow barrier elements 14 is formed by a displacement of the thread between the layers of cloth. In addition, the creation of these joints can be initiated and stopped at will by simply controlling the harnesses during the weaving operation. The required control of the weaving process to form the joints in desired locations is achieved by dividing the width of the fabric into a multiplicity of zones of width which depends on the final desired geometry of the element to be produced. In preferred practice, the warp yarns for each of these zones are attached to a different set of control harnesses than the warp yarns of the adjacent zone. Since two layers of fabric are being formed, a minimum of four harnesses controls the movement of the warp yarns in each zone. As will be appreciated by those skilled in the art, it is the nature of some types of weaving equipment that the distance of the harness from the fabric forming point can affect the attention of the warp yarn. In order to avoid the tension imbalance within each zone across the width of the fabric, it is proposed that the warp yarns for each tissue area can be dispersed through the depth of all the harnesses. By way of example only and not limitation, in case there are three areas of tissue that require the use of dpce harnesses; a quarter of the warp yarns of the first weaving area will be worn by harness number 1, a quarter of the warp yarns for the first weaving area will be carried by harness number 4, a quarter of yarns of Warp for the first weaving area will be carried by the harness number 7 and a quarter of the warp yarns for the first weaving area will be carried by the harness number 10. The warp yarns for the second and third weaving zones can distributed in a similar way among the available harnesses. In the preferred practice of the present invention, two woven fabric layers 24 are formed simultaneously from a polymeric yarn such as polyester, nylon 6 or nylon 6.6, using four repeating patterns each of which incorporates four warp yarns and four yarns. of plot. Repeat patterns using four threads in each fabric direction allow for the simultaneous formation of two layers of the potentially preferred fabric configuration using a single knitting machine. In addition, the repetition of a tissue pattern determined across the length and width of the fabric results in two layers that are uniform and independently of one another. Subsequent to the formation, the portions of the fabric may be coated with permeability blocking materials including by way of example only, silicone, polyamides, polyurethane, polyacrylates and mixtures thereof. In preferred practice, these coatings will be present at levels no greater than 33.49 grams per square meter of fabric, more preferably, no greater than about 20.69 grams per square meter of fabric, and especially preferably not greater than about 13.40 grams per square inch of fabric. square meter of fabric in such a way that the coating remains in the interstitial gaps between the threads without essentially covering the threads themselves. It has been found that by shifting from one basic fabric pattern to another through the width and / or length of the fabric that controlled formation of fabrics can occur in joints extending between the layers of the fabric 24 both in the warp direction as of plot. Figures 4A-4D illustrate the potentially preferred four-wire repeat patterns useful in accordance with the present invention. In illustrated and potentially preferred practice, the warp yarns 1 and 3 in each fabric pattern will be placed in the same fabric layer 24 while the warp yarns 2 and 4 are placed in the other layer. Likewise, the warp yarns? "And" C "must remain in one layer while the weft threads • B '' D 'are placed in another layer.Therefore, when the pattern fabric conforms to Figure 4A when the warp yarn "A" is inserted and passed over the warp threads 1, 2, 3 and under the warp yarn 4 to form part of the first cloth layer When the warp yarn "B" it is inserted, passes over the warp yarn 1 and under the warp yarns 2, 3 and 4 so as to be part of a second layer of fabric When the warp yarn "C" is inserted, it passes over of the warp threads 1, 3 and 4 while passing under the warp yarn 2. Finally, when the weft yarn "D" is inserted, it passes under the warp threads 1, 2 and 4 and above the yarn 3 of warp to complete a fabric interaction in the second layer of fabric.Thus, a first or upper layer of fabric is formed of the yarns 2 and 4 of warp and weft threads "A" and "C" and a second or lower fabric layer are formed from warp threads 1 and 3 and weft threads "B" and "D" Similarly in practice preferred, when knitted according to the diagram in Figure 4B, the first or upper layer contains the warp yarns 1 and 3 and the weft yarns "A" and "C" while the second or lower layer contains the yarns of warp 2 and 4 and the weft threads "B" and "D". When knitting according to Figure 4C, the first or upper layer contains the warp yarns 2 and 4 and the weft threads "B" and "D" and the second or lower layer contains the warp threads 1 and 3 and the weft threads "A" and " C ". When knitting according to the pattern in Figure 4D, the first or upper layer contains the warp yarns 1 and 3 and the weft threads "B" and "D" and the second or lower layer contains the warp yarns 2. and 4 and the "A" and "C" weft threads. A two-layer fabric 24 having an upper layer 30 and a lower layer 32 (Figures 5 and 6) each of which includes a multiplicity of interwoven warp yarns with a multiplicity of weft yarns as illustrated in Figures 5 and 6 can therefore be formed by combining the fabric patterns illustrated in Figures 4A-4D. According to one aspect of the present invention, it has been determined that through the manipulation of the knitting patterns, the interconnection joints 16 of a nature essentially impermeable to gas can be formed between the upper and lower layers 30, 32 of the fabric structure 24. The strength and gas imperviousness of the gaskets is believed to be greatly improved by the fact that the gaskets formed in accordance with the present invention essentially prevent so-called "floats" of yarn from occurring at the point of gasket formation. . A yarn flotation for this object is defined as having occurred that a warp or weft yarn passing either above or below two or more consecutive transverse yarns in such a way that it does not pass between these transverse yarns. That is, in the preferred embodiment, the interwoven relationship above and below between the warp yarns and the weft yarns is maintained through the seal 16 even when either the warp yarns or the weft yarns were moved from the warp yarns. upper layer 30 to lower layer 32. This displacement of preference occurs within the space of a single thread. This feature of the present invention is believed to represent a considerable and important advantage in relation to the above interwoven connections that typically provide raised yarns and / or require the use of fairly significant interwoven areas where the upper layer and the lower layer they form in a single thick voluminous layer during at least several wire positions to provide an interconnection. As illustrated, at least a portion of the flow barrier elements 14 are formed of gaskets 16 spaced relatively narrowly to protect against undue slip which is believed to increase permeability and to protect against breakage. In potentially preferred practice, no more than twelve threads in each fabric layer (twenty-four threads in total) will be placed in the region between the closely spaced seams. In especially preferred practice, no more than eight threads in each layer of fabric will be placed between closely spaced joints. In especially preferred practice only about two to four threads in each layer of fabric will be placed in the region between closely spaced joints (Figures 5 and 6). As will be appreciated, in addition to the straight line configurations, closely spaced complementary gaskets that are separated by two independent layers of fabrics in accordance with the present invention may also be formed in a curved format if a jacquard fabric system is used. The use of very closely spaced seals is believed to be particularly useful in forming the flow barrier elements 14 that define the perimeter of the cushion. This use of closely spaced seals 16 can be particularly beneficial for forming elongated and inflatable tubes in accordance with the practice of the invention wherein the seals 16 run in the warp direction essentially along the length of the tubes, thus forming a connecting barrier edge with one or both of the ends of this tube that remains open. It is proposed that using the gasket structure in accordance with the present invention that these tubes with interconnect barrier seals 16 extending in the warp direction as illustrated in Figure 3B, can be formed on a loom on a base essentially continuous. In accordance with the potentially preferred practice of the present invention, joints that are formed between the upper layer 30 and the lower layer 32 are achieved between complementary tissue patterns such as those illustrated in Figures 4A-4D. In an important aspect of the present invention it has been found that even complex designs of finished woven articles can be achieved by repeating multiples of a relatively small number of basic weaving patterns by controlling the movement of the harnesses that move the warp threads upwardly. and downwards opening the shed for the insertion of the warp threads in this way. An example is illustrated in Figure 5 where the first pattern 40 such as the pattern 4A is a zone of tissue adjacent to another tissue region using a second pattern 42, as illustrated in Figure 4D to effect a displacement. of the weft yarns from the upper layer 30 to the lower layer 32. A similar gasket is then formed in close proximity by commuting back to the first pattern 40. In Figure 6 a pair of gaskets extending in the weft direction between the upper layer 30 and the lower layer 32 of the woven fabric is illustrated. . This preferential meeting is formed by weaving the pattern as illustrated in Figure 4C in an area between the areas where the pattern illustrated in Figure 4B is used. As can be seen, in the illustrated and preferred embodiment the joints 16 are formed without interruption, the basic joints 16 are formed without interrupting the basic weaving pattern of the threads moving from one layer to another. As will be recognized, the application of the present invention allows joints to be applied that extend both down the length of the fabric as well as across the width using a series of repeating fabric patterns. For purposes of disclosure, Figure 7 illustrates some of a number of possible connections along both the length and width of the fabric as they may be formed by practicing the present invention. As illustrated, the fabric may include a number of warp zones across the width controlled by the harnesses that carry the warp yarns that are coupled as desired in different fabric sections along the length that are formed . As will be recognized, the designation of areas through Figure 7 corresponds to the basic fabric patterns illustrated in Figures 4A-4D used in those sections. While it is believed that fabric patterns other than those illustrated herein may be used, it is nevertheless believed that in order to obtain the most desirable results in terms of strength and maintenance of air impermeability, the placed fabric patterns adjacent to each other along their length of their width of the formed fabric must be complementary to each other in such a way that the warp and weft threads are intertwined through the transition as illustrated in the Figures 5 and 6. That is, the relationship is maintained whereby each thread passes over and under the successive threads in an alternative manner while skipping the interlacing relationship with threads as they meet. The importance of avoiding these skipped yarns or "floats" is that the skipped yarns tend to loosen the structure of the fabric thus providing a potential outlet for the inflation gases in the air pocket formed in accordance with the present invention. In addition to the generation of relatively complex flow barrier elements through a non-stitched bag as shown in Figures 1, 2 and 3A, it is possible within the scope of the present invention to form restraint cushions of simpler configuration using joints of essentially straight line geometry formed in the manner described above. By way of example only and not limitation, an inflatable cushion 210 is illustrated in Figure 8 which includes a number of essentially straight line barrier elements 314 positioned vertically across the width of the cushion. As will be recognized, these barrier elements may be of any length and may be of joint construction either single or multiple as may be required for strength in a particular application. By way of example, it may be desirable to use closely spaced double seal lines as used in the illustrated barrier elements and as described above. In addition, of the extended line connections established between the layers of the woven fabric construction 24, it will also be appreciated that the application of the present invention allows the establishment of essentially spiky connections as may be desired for certain configurations. A potential embodiment of the spike connections as may be used is illustrated in Figure 9 where the flow barrier elements 414 adopt a double box cross configuration which may be useful for distributing the load at those points. It is also proposed that it is within the scope of the present invention to use combinations of horizontal and vertical connections in order to channel the inflation medium to all desired locations. One of these arrangements is illustrated in Figure 10. Although certain potentially preferred embodiments have been illustrated and described, other embodiments of the invention will become apparent to those skilled in the art when taking into account the aforementioned specification and the practice of the invention disclosed herein. It is intended that the specification be considered as explanatory and to be explained only within the true scope and spirit of the invention will be indicated only by the claims allowed.

Claims (7)

1. CLAIMS: 1. An inflatable airbag cushion comprising: a non-jacquard construction bag wherein the bag comprises a face portion and a back portion formed of a first layer of fabric and a second layer of fabric, each of the first and second fabric layers are defined by a plurality of polymeric warp yarns running in the warp direction interposed by a plurality of polymeric weft yarns running in the warp direction essentially transverse to the warp direction; the bag further comprises a plurality of fabrics in the gaskets, the fabrics in the gaskets are placed in order to define flow barriers between the face portion and the back portion in such a way that during the introduction of a gas into the bag, the flow of gas within the bag is limited by the fabric in the gaskets thus containing the gas from locations where inflation is desired if inflation of the bag is restricted in locations where the fabric in the joints is present; at least a portion of the fabric in the joints extends at least in the warp direction between the face and the back portion and all the woven joints essentially consist of one or more segments of straight line. The invention according to claim 1, wherein the flow barriers comprise box structures placed through the interior of the bag. 3. The invention according to claim 2, wherein the box structures are multi-cornered construction. The invention according to claim 1, wherein the warp yarns and the weft yarns are formed of a polymer that is selected from the group consisting of polyester, Nylon 6 and Nylon 6.6. The invention according to claim 1, wherein the fabric in the joints maintains the interlacing through its widths in such a way that they are essentially free of the yarn floats. The invention according to claim 1, wherein at least a portion of the flow barriers comprises tissue essentially parallel to the joints separated from one another by a connecting portion comprising two separate layers of woven fabric where The width of this connection portion is such that each of the two layers has a width that covers eight or a smaller amount of threads. 7. The invention according to claim 1, wherein the bag further comprises a porosity blocking coating.