Land vehicles – Wheeled – Attachment
Reexamination Certificate
2000-08-31
2001-10-02
Culbreth, Eric (Department: 3611)
Land vehicles
Wheeled
Attachment
C280S728100
Reexamination Certificate
active
06296276
ABSTRACT:
TECHNICAL FIELD
The invention relates to a gas bag.
BACKGROUND OF THE INVENTION
A gas bag known from U.S. Pat. No. 5,464,250 has a zigzag-shaped section of fabric, sewn at the edge sections with the fabric layers, which section acts as a spacer. The effect of this spacer is to prevent the gas bag from bulging excessively, i.e. from becoming too thick between its edges. Other types of spacers are so-called tethers, the ends of which are sewn to the fabric layers and limit the spacing locally. The fitting of spacers is a very expensive and elaborate procedure and hinders inversion of the gas bag after sewing. The arrangement of the spacers is therefore very complicated, and for manufacturing reasons the spacers cannot be arranged at any site whatever. On the other hand, the inflated gas bags would become unnecessarily thick without spacers, which presents problems. Optimum restraint calls to some extent for no extreme thickness of the gas bag, so that an unnecessarily large amount of gas would be needed to completely fill the gas bag. Moreover, as the thickness becomes greater, the risk of the occupants being struck by the deploying gas bag also increases.
For this reason, side gas bags (known as “window bags”) are produced that have numerous, parallel, narrow chambers. Here, the fabric layers are interwoven in one piece on the outside contour of the gas bag and between the chambers. The numerous chambers, in some cases elongated and having a low cross-section, can increase the time to inflate the gas bag. Furthermore, these require precise delivery of the gas to the chambers themselves, e.g. by means of a gas lance which extends along the roof frame.
BRIEF SUMMARY OF THE INVENTION
The invention relates to a gas bag which has at least one chamber and which is distinguished by spacers that can be manufactured with extreme ease and at low costs, at the same time the spacers having less influence on the flow within the gas bag than those previously known. Furthermore, the gas bag proposed is distinguished by the possibility of having spacers at any sites and in any number without making the manufacture of the gas bag significantly more expensive or more difficult. This is accomplished with a gas bag which comprises at least two fabric layers arranged opposite one another and delimiting the at least one chamber which can be filled with gas. The fabric layers each form or define a surface area and consist of threads which comprise warp and weft threads. The gas bag further comprises at least one spacer which is joined to the fabric layers and, in an inflated state of the gas bag, limits a distance between the fabric layers. The spacer is made up of some of the threads which, related to the inflated state of the gas bag, depart from the surface area formed by their associated fabric layer and extend towards their opposite fabric layer to be joined to threads of the opposite fabric layer. The term “thread” used throughout the description stands for warp and/or weft threads of the gas bag fabric. In the proposed gas bag, the spacers are formed by several warp and/or weft threads which depart, so to speak, from the composite fabric and extend towards the opposite fabric layer. The spacer is, therefore, not a separate part that must be attached to the fabric layers, but an integral part of the fabric layers. The technique of partial interweaving of fabric layers permits the spacers to be positioned anywhere. Moreover, in the region where they function as spacers, the warp and/or weft threads hinder the flow of gas within the gas bag only slightly because they do not necessarily have to be designed as a sheet-like fabric in the region of the spacer. The gas can therefore flow between the individual threads and cause rapid deployment of the gas bag. Due to the inexpensive and variable technique of interweaving in one piece, the invention makes it possible for the first time to manufacture at low cost large-area gas bags that almost resemble mattresses.
The warp and/or weft threads that function as spacers can, after departing from the surface formed by the associated fabric layer (usually the outside wall of the gas bag) and after formation of the spacer, go into the opposite fabric layer and thus become an integral part of this fabric layer. Furthermore, after the spacers have been formed, they can go back into their associated fabric layer and integrate with it. However, they must then be joined to warp and/or weft threads of the opposite fabric layers in the region of the spacer. This can be accomplished, for instance, by also separating warp and/or weft threads from the composite arrangement of the opposite fabric layer and joining them between the two external walls of the gas bag to the warp and/or weft threads separated from the composite fabric of the opposite fabric layer.
In this way, spacers can be made that form an H shape, an X shape, or a Y shape when viewed in cross-section.
The warp and/or weft threads forming the spacer are missing present in the region of the spacer in the fabric layer associated with it. Consequently, the fabric layer is less gas-tight at this point. This can be used to deliberately provide the external wall of the gas bag with a specific gas permeability. If the gas permeability becomes too great, however, the fabric layer providing the warp and/or weft threads can also be coated, at least in the region where the spacer is provided. In the case of side gas bags, for instance, that should be filled completely for as long as possible, the fabric layers are coated with film, preferably on the outside. Numerous spacers can thus be provided because, due to the coating with film, it is no longer disadvantageous in terms of gas permeability for the external wall to have just a few threads in the region of the spacers. The fabric itself thus forms essentially a supporting structure only and the gas-tightness as such is provided by the film.
When the gas bag is a large-area side gas bag and has several chambers formed by interweaving into one piece the opposite fabric layers, the spacers described above are provided additionally within the chambers. Although the chambers themselves have a small cross-section, the thickness of the gas bag can be reduced once again by the spacers and be brought down to the dimension that is adequate for the purposes of restraint. The spacers can be of elongated and, for example, linear shape, i.e. form an elongated, gas-permeable wall. The spacers can, however, also be point-shaped or ring-shaped, rather like a bed mattress where knobs visible on the outer side form the end of spacers.
REFERENCES:
patent: 5464250 (1995-11-01), Sato
patent: 5566977 (1996-10-01), Wipasuramonton
patent: 5651395 (1997-07-01), Graham et al.
patent: 5685347 (1997-11-01), Graham et al.
patent: 6000442 (1999-12-01), Busgen
patent: 6113141 (2000-09-01), Baker
patent: 6152481 (2000-11-01), Webber et al.
patent: 6168191 (2001-01-01), Webber et al.
patent: 3903216 (1990-08-01), None
patent: 4324487 (1995-01-01), None
Culbreth Eric
Lum L.
Tarolli, Sundheim, Covell Tummino & Szabo L.L.P.
TRW Occupant Restraint Systems GmbH & Co. KG
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