[0030] First refer to figure 2 , showing a representation of the traditional non-inflatable region of an IC airbag, such as can be used in figure 1 In the known airbag 1 shown.
[0031] figure 2 A grid of cells 8 is shown, with some cells represented by white 9 and others shaded 10. figure 2 Schematic representation of the weaving of one of the fabric layers to make the non-inflatable region of the airbag. The grid of cells corresponds to the warp and weft threads of the fabric layer, with the vertical columns of the grid representing the warp threads and the horizontal rows of the grid representing the weft threads (or, vice versa).
[0032] if figure 2 The layer shown is considered to be the upper layer of a two-ply fabric, the shaded cells 10 represent the intersections where the warp threads pass above the weft threads, and the white cells represent the intersections where the warp threads pass below the weft threads. Technically savvy readers should recognize figure 2 The entire pattern represented is a standard plain weave pattern.
[0033] exist figure 2 In some of the cells 11, shaded cells 10 can be expected where white cells appear (with the normal routing of the weave pattern). These units 11 represent where one of the yarns extends across another fabric layer (not shown), thus forming a connection between the two fabric layers.
[0034] figure 2 is a grid of 180 x 152 cells (representing 180 "warps" and 152 "fills"), or 27360 cells, representing 180 warps and 152 wefts, with 27360 intersections between the yarns ( For the purposes of this document, the point of intersection is the location where the warp and weft threads cross each other when the fabric layer is viewed in a direction perpendicular to the plane of the layer). In this mesh, a connection is formed between the two layers of fabric. A connection is preferably defined as a position in which a yarn of one layer extends across and around the distal side of a yarn of the other layer.
[0035] If a yarn of one of the layers extends across to the other layer and around the distal side of two successive yarns of the other layer, this is preferably defined as a double connection.
[0036] exist figure 2 In the example shown, there are 144 connection points 11 between layers. Thus, of all the intersections of the warp and weft of the layers shown, an intersection of 0.0052 (approximately) represents the connection between the two layers. Therefore, it can be said that figure 2 The connection density in the pattern shown is 0.0052. It should be understood that if the non-inflatable regions of the airbag are made repeatedly of such patterns (i.e. figure 2 repeating the pattern end-to-end and edge-to-edge any number of times), the non-inflatable region will have an overall connection density of approximately 0.0052.
[0037] For clarity purposes, image 3 for figure 2 A close-up view of the area of the style shown.
[0038] figure 2The weave pattern shown is a known weave pattern that has been used in non-inflatable regions of IC-type airbags. When testing non-inflatable regions woven in this manner, the average stiffness of the non-inflatable regions (ie, the average stiffness after multiple measurements) was found to be in the interval 100 to 140 N, measured on the King stiffness table (according to ASTM D 4032 is used to perform these measurements). In the stiffness values given below, the same measurement method is used and the different non-inflatable regions in question are made in substantially the same way, i.e. there are yarns of the same type and density, and the The interval or spacing is the same. The stiffness values can therefore be directly compared with each other.
[0039] Figure 4 Another grid of cells 8, this grid represents a first weave pattern embodying the present invention. exist Figure 4 In, relatively short "lines" form cell 11, representing the connection between the two layers. exist Figure 4 In the embodiment shown, the threads are oblique (ie, oblique with respect to the directions of the warp and weft) and are arranged at 45° to both the directions of the warp and weft. Each of the connected lines is generally straight, and the lines are arranged to follow a zigzag configuration.
[0040] one more time, Figure 4 A grid of 180x152 cells is shown with 22 connections within the grid. Thus, this pattern represents a connection density of 0.00080 (approximately).
[0041] Subsequent testing found that the non-inflatable regions made with this weave pattern had a King stiffness in the range of 40 to 80N. It is understandable that this is figure 2 The traditionally braided style shown in is much less rigid.
[0042] go to Figure 5 , this figure shows another grid of cells 8 representing a second weave pattern embodying the present invention. exist Figure 5 In , a substantially continuous line of cells 11 is formed, representing the connection formed between the two layers. In the example shown, the line is in a zigzag configuration. one more time, Figure 5 A grid of 180x152 cells is shown, and within this grid there are 90 connections. Therefore, this pattern represents a connection density of 0.0033 (approximately).
[0043] Subsequent testing found that non-inflatable regions made with this woven pattern also had a King stiffness range of 40 to 80N. Again, this is better than figure 2 The conventional braided style shown is much less rigid.
[0044] Figure 5 The connection density of the pattern shown is believed to be the maximum connection density of the pattern embodying the present invention. If the connection density exceeds this value, the resulting non-inflatable area may have an undesirably high stiffness, making it difficult to crimp the airbag for packaging and installation.
[0045] refer to Image 6 , this figure shows another grid of cells 8 representing a third weave pattern embodying the present invention. This style and image 3 Similar to that shown in , but instead of the short lines of connections 11 following a zigzag pattern, there are separate, spaced-apart connections 11 that follow a zigzag pattern. one more time, Image 6 A grid of 180×152 cells is shown, and there are 11 connections in the grid. Thus, this pattern represents a connection density of 0.0040 (approximately).
[0046] Subsequent testing found that the non-inflatable regions made with this weave pattern again had a King stiffness range of 40 to 80N. This is also better than figure 2 The conventional braided style shown is much less rigid.
[0047] Image 6 The connection densities of the patterns shown are considered to be the minimum connection densities of the patterns embodying the present invention. It is predicted that if the connection density is less than this value, the two layers of the airbag will not be adequately connected to each other and the airbag will not maintain its correct configuration during crimping/packaging and during deployment. It was also found that with a lower number of connection points, these connection points may be mistaken for defects in the weaving pattern during quality inspection.
[0048] In a preferred embodiment of the present invention, in the region of 180 yarns of one type interwoven with 152 yarns of the other type (as discussed above), there are approximately 15 to 40 connections, corresponding to The connection density is between about 0.00055 and 0.0015.
[0049] In the examples given above, the connection points are arranged in lines that follow a zigzag or zigzag pattern. This was found to give the woven pattern the desired stiffness.
[0050] Additionally, arranging the connection points in this manner makes it relatively easy to distinguish the connection points from unwanted defects in the weave pattern. In the final stages of production, the woven material is usually scrutinized for defects. The detection can be performed by a human operator, or by a machine with one or more cameras. In either technique, arranging the connection points in a predictable pattern minimizes the possibility of mistaking the connection points for defects, and the camera system can be trained to recognize that the lines of these connection points are not checked as defects. As can be expected, this inspection step would be more difficult if the connection points were evenly distributed over the braided pattern.
[0051] A zig-zag or zig-zag pattern provides a repeating and predictable pattern that remains generally "level" for the weave pattern.
[0052] In use, an airbag comprising a non-inflatable region according to the above may be produced by any suitable method. For example, conventional looms for weaving OPW airbags can be used, with the appropriate weave pattern for one or more non-inflatable regions of the airbag being programmed into a computer system that controls the operation of the loom. Readers who know the technology will easily understand how this can be achieved. Part or all of the fabric of the airbag is then coated (as is well known in the art), eg, to reduce the permeability of the fabric and/or to impart thermal/flame retardancy to the fabric.
[0053] The completed airbag is rolled and/or folded for installation in the vehicle in the usual manner.
[0054] It will be appreciated that embodiments of the present invention provide airbags with improved characteristics, particularly with respect to crimping and packaging, without any loss of performance during inflation and deployment.
[0055] When used in this specification and in the claims, the terms "comprises" and "comprising" and variations thereof are meant to include the specified features, steps, or integers. This term should not be interpreted as excluding the presence of other features, steps or elements.
[0056] The foregoing or the following claims or drawings are disclosed, in their specific forms or in terms of means for performing the disclosed functions, or in terms of methods or processes for achieving the disclosed results. The features expressed may, as appropriate, be implemented in different forms, separately or in any combination of these features.
