EP2040959A1

EP2040959A1 - Method for producing a seam

Info

Publication number: EP2040959A1
Application number: EP07765195A
Authority: EP
Inventors: Hans-Albert Graefe; Ralf Krause
Original assignee: Global Safety Textiles GmbH
Current assignee: Global Safety Textiles GmbH
Priority date: 2006-07-14
Filing date: 2007-07-13
Publication date: 2009-04-01
Also published as: CN101448684A; ZA200809040B; WO2008006612A1; DE102006032805A1; CA2650252A1

Abstract

A method for producing an additional seam in a single-layer seam structure of a one-piece-woven-airbag (OPW bag), wherein the single-layer seam structure, which merges at least on one side into a two-layer chamber region, has an upper surface (O) and a lower surface (U), the method being characterized in that the two surfaces (O, U) are sealed thermally to each other in a gastight manner in an additional seam (3, 13).

Description

SCHROETER LEHMANN FISCHER & NEUGEBAUER

Patent Attorneys European Patent Attorneys European Trademark Attorneys Wolfratshauser Str 145, 81479 Munich, Germany

New international patent application

BST Safety Textiles GmbH 13th July 2007

Our sign: 28-634a-where Fi / ni

Method of making a seam

The present invention relates to a method for making an additional seam in a single-ply seam construction of a one-piece woven airbag (OPW bag), the single-ply seam construction having an upper surface and a lower surface.

There are air bags, which are sewn together from textile fabrics, as well as in one piece woven air bags, known as one-piece woven or OPW air bags, which have single and multi-layer areas and on the outer upper and lower surfaces of a pad z. B. a film is applied. The overlay here serves the purpose of avoiding escape of a fluid or gas from the multilayer region of chambers formed between the layers of the airbag. Although the pads used have a very low to no air permeability, the air bags just described are not sufficiently dense. Especially in the tissue plane, d. H. Inside the tissue surface, air can flow between the supports through the "seam area" lying between the supports. One speaks of a horizontal air loss. As a result, today required by the industry lifetimes of airbags or airbags, especially side or curtain airbags are difficult to achieve or only by very expensive generators that nachfördern example, in several stages the escaped gas, or be compensated by supplying larger amounts of propellant , which compensate for the gas loss.

In addition, the air bags just described have the disadvantage that can leak through gas into the interior of a relevant motor vehicle, in which such an airbag is used. This can lead to health damage from the gas itself or its high temperature for the vehicle occupants. 28-634a-where - 2 - July 13, 2007

DE 103 26 757 A1 (BST) discloses a method for producing an airbag, which is characterized in that single-layered regions are sealed in such a way that they are substantially impermeable to fluids. As practice has shown, even this method is not yet sufficiently satisfactory to meet the specifications required by industry.

The invention has for its object to provide a method for producing an additional seam in a single-layer seam construction of a one-piece woven airbag (OPW bag), wherein the single-layer seam construction has an upper surface and a lower surface, with which from the Prior art known disadvantages avoided or at least greatly reduced.

The object is achieved by a method for producing an additional seam in a single-layer seam construction of a one-piece woven airbag (OPW-bags), wherein the single-layer seam construction, which merges at least to one side in a two-layer chamber area, an upper surface and a having lower surface, wherein the method is characterized in that the two surfaces are sealed together thermally gas-tight. An additional seam produced by the method according to the invention has the particular advantage that it prevents the escape of gas from the OPW bag through the single-layered seam construction and does not damage the OPW bag, e.g. is perforated by a sewing thread of an additional seam. This is particularly advantageous if the woven circumferential seam of the OPW bag is provided with such an additional seam. By means of the additional seam produced according to the method of the invention, no gas can escape from the OPW bag in the tissue plane of the single-layered seam construction. The disadvantages described above, such as a short service life of the inflated OPW bag or the need for increased gas refills during the purging, are eliminated. There is no more "horizontal air loss".

Under thermal sealing, according to the invention, a fusion of individual packages z. B. a woven seam construction understood. This process is described, inter alia, in "Dictionary of Man-Made Fibers", Hans J. Koslowski, Ist Edition 1998, published by International Business Publishers, Frankfurt am Main, ISBN 3-87150-583-8 on page 119. In the "melting point", the transition of polymers from a crystalline to a liquid state takes place. As a result, several yarn packages can at least partially connect to one another via the liquid state-depending on the intensity of the thermal seal-and form a barrier against a horizontal air loss. The upper surface 28-634a-where - 3 - July 13, 2007

and the bottom surface of the single-ply-woven seam construction thus provide a "wall" of fused yarns or filaments after thermal sealing.

The term "single-ply seam construction of a one-piece woven airbag (OPW-Bags)" includes all woven seam constructions of the OPW, in particular also seams with "mating tube" construction, as known to the person skilled in the art.

In an advantageous development of the present invention binding yarn-floating yarn packages of the single-layer seam construction are combined under thermal influence. By this measure, a textile gas bag is provided to produce a low-cost adaptive airbag module (without elaborate generator technology).

The achievable due to the invention cost-effective reduction of the use of material results in particular as a result of the now possible lower thread density of the OPW bag. By means of the invention, it is also possible to seal off a weave seam which is no longer sufficiently dense by the reduction of the thread densities in the surface in terms of horizontal air loss.

In an advantageous development of the present invention, both surfaces are welded together by means of at least one weld. Although ultrasound or laser welding equipment for joining thermoplastically deformable textile fabrics and at the same time the problem of so-called horizontal air loss between two assembled fabrics is well known, this inventive solution has not been found. The great advantage achievable by applying the method according to the invention is that it can be used to create a seam for the gas-tight sealing of two textile surfaces of a single-layered fabric, in particular for producing an OPW bag, with which a horizontal gas barrier is guaranteed. As a result, required by the prior art specifications such as life and Lnungsackfestigkεit are much easier maintained than in air bags from the prior art, in which the degree of tightness is insufficient due to the air-permeable seams.

An advantageous development of the present invention is that the two surfaces are coated before the thermal sealing with a / a gas-tight coating, film or laminate. This results after the thermal sealing a cost-produced all-round gas-tight OPW bag, which is already ready for final assembly in the module. 28-634a-where - 4 - July 13, 2007

In another advantageous embodiment of the invention, the method is refined to the effect that the weld is produced by means of laser or ultrasonic welding. The methods mentioned are economically feasible and proven reliable method.

Briefly, the technology underlying the method according to the invention consists in the fact that the tightness of an airbag in the seam area in the application case, i. H. in the moment in which the air bag is inflated in a very short time under high pressure, is ensured after use of the method according to the invention. On the other hand, in the case of OPW bags known from the prior art, the tightness of a previously woven seam is reduced due to the pressure built up in the airbag, so that a horizontal air barrier actually formed by the seam dissolves, since the pressure in the airbag due to the load is the two Pressing surfaces of the woven single-layer seam area apart. Of course, then the inflation gas is the path of least resistance namely through the seam area, d. H. horizontally or between the two surfaces - "in the tissue plane" - and escape in this way from the airbag.

In an advantageous development of the method according to the invention, the two textile surfaces are laminated prior to sealing. The advantage for this has already been mentioned above. When using laminates or other sealing layers, it is possible to use loose fabric structures, for example also leno fabrics, which in such cases then rather have a geometry-forming and structure-forming function than a sealing function. This would indeed taken over in accordance with the training just described of airtight pads, which lead in combination with the weld seam according to the invention to an almost dense airbag in use.

For a better understanding of the invention, this will be described briefly with the aid of a drawing below with reference to an embodiment.

Fig. 1 shows a highly schematic of a sectional view of an airbag.

Fig. 2 shows a highly schematic of a sectional view of an airbag in the manufacture of an additional seam according to the inventive method. 28-634a-where - 5 - July 13, 2007

Fig. 3 shows a section of an airbag and an associated additional seam, which was produced by the method according to the invention.

1 shows a part of a piece-wound airbag or OPW-bag 9, consisting of a woven single-layered seam construction or woven seam 20 having an upper surface O and a lower surface U, wherein the seam construction 20 to the right side (in FIG. 1) merges into a two-layered chamber region with an upper fabric layer 22 and a lower fabric layer 23, which enclose a chamber 24. The exemplary width of the single-ply seam construction 20 is marked with the reference numeral 17. In the inflated state of the OPW bag 9, the pressurized gas in the chamber 24 urges u.a. in the direction of arrow 6 and tries to escape in the direction indicated by a dotted line tissue plane 25.

2 shows, by way of example, a schematically illustrated thermal sealing device 2 with a sealing head 4, by means of which the additional seam 3 (see also FIG. 1) is formed. By means of this device, yarn packages of the single-layer seam construction 20 which bond with respect to binding technology under thermal action can be bonded under thermal action. The strength of the woven seam 20 is achieved by differentiated stepped floats in the woven seam 20. The weave can go in extreme cases to the plain weave L 1/1.

The upper fabric layer 22 and the lower fabric layer 23 enclosing the chamber 24 may each be coated with a gas-tight overlay such as a coating, film or laminate. This should be indicated by the reference numerals 1 and Ia. By means of the coating just mentioned, the OPW bag 9 is sealed gas-tight to the outside. The sealing of the OPW bag 9 in the fabric plane 25 is taken over by the additional seam 13 produced by the method according to the invention. This results in a completely gas-tight sealed OPW Rag with all its, here several disparate advantages.

The sealing device may also be a laser welding machine used according to the invention, for example with a laser welding machine (not shown) which welds the upper surface O and the lower surface U in the seam construction 20 gas-tightly together. 28-634a-where - 6 - July 13, 2007

The course of an additional seam 13 shown by way of example in FIG. 3 in the edge region 17 of a schematically illustrated airbag 9 is shown in dotted lines in FIG.

FIGS. 1 and 2 qualitatively show sections of the method according to the invention which are necessary for understanding the invention, the focus being on the method for producing an additional seam which seals two textile surfaces.

In addition to the advantages already mentioned, the use of the method according to the invention leads to further advantages, for example reduction of the use of material and thus the weight of an airbag treated by the method according to the invention, as well as reduction of the installation space due to the possible use of thinner textile fabrics. Due to the now advantageously possible lower yarn density results in a higher running meter per unit time in the weaving, which contributes to the reduction of costs. Since the use of the inventive method allows a much better detectable performance of the airbag in the application, for example, an adaptive vent and the bag pressure can vote much better.

Last but not least, there is the advantage that lighter OPW bags can be produced with the method according to the invention. Due to the now possible lower weight of the airbag, it is advantageously possible to disarm the nevertheless somewhat aggressive bag-opening behavior.

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Claims

28-634a-where - 7 - July 13, 2007PATENTIAL CLAIMS

A method for producing an additional seam in a single-layer seam construction of a one-piece woven airbag (OPW-Bags), wherein the single-layer seam construction, which merges at least to one side in a two-layer chamber area, an upper surface (O) and a lower Surface (U), characterized in that the two surfaces (O, U) in an additional seam (3, 13) are sealed with each other thermally gas-tight.

2. The method according to claim 1, characterized in that bonding technically floating yarn package of the single-layer seam construction (20) are connected under thermal action.

3. The method according to claim 1 or 2, characterized in that the two surfaces (O, U) by means of at least one weld (3, 13) are welded together.

4. The method according to claim 1, 2 or 3, characterized in that the two surfaces (O, U) before the thermal sealing with a / a gas-tight coating, film or laminate (1, Ia) are coated.

5. The method according to claim 3 or 4, characterized in that the additional seam (3, 13) is produced by means of laser or ultrasonic welding.

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