U.S. patent application number 11/001772 was filed with the patent office on 2005-07-28 for airbag and method of producing an airbag.
Invention is credited to Berger, Johann, Huber, Norbert, Ruschulte, Jorg, Saint-Denis, Holger.
Application Number | 20050161919 11/001772 |
Document ID | / |
Family ID | 34796545 |
Filed Date | 2005-07-28 |
United States Patent
Application |
20050161919 |
Kind Code |
A1 |
Berger, Johann ; et
al. |
July 28, 2005 |
Airbag and method of producing an airbag
Abstract
The invention relates to a two-ply airbag consisting of a
textile surface structure, said plies lying opposite one another
and enclosing at least one chamber that can be filled with gas. The
piles have surfaces that face outwards. The airbag is characterized
in that coatings, which are suitable for sealing and reinforcing
the airbag, are applied to said surfaces.
Inventors: |
Berger, Johann; (Alfdorf,
DE) ; Saint-Denis, Holger; (Rheinfelden, DE) ;
Huber, Norbert; (Bad Sackingen, DE) ; Ruschulte,
Jorg; (Wehr, DE) |
Correspondence
Address: |
HARNESS, DICKEY & PIERCE, P.L.C.
P.O. BOX 828
BLOOMFIELD HILLS
MI
48303
US
|
Family ID: |
34796545 |
Appl. No.: |
11/001772 |
Filed: |
December 2, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11001772 |
Dec 2, 2004 |
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PCT/EP03/05697 |
May 30, 2003 |
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Current U.S.
Class: |
280/734 |
Current CPC
Class: |
B32B 5/08 20130101; B32B
5/26 20130101; B32B 5/24 20130101; B32B 2305/18 20130101; B32B
2310/14 20130101; D06N 3/0002 20130101; B32B 5/024 20130101; B32B
37/0053 20130101; B32B 2038/0024 20130101; B32B 38/0008 20130101;
B32B 5/022 20130101; B60R 21/235 20130101; B60R 2021/23514
20130101; B32B 38/00 20130101 |
Class at
Publication: |
280/734 |
International
Class: |
D03D 001/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 4, 2002 |
DE |
102 24 771.4-42 |
Claims
The invention claimed is:
1. An air bag comprising two non-gastight plies of a textile sheet
fabric, the plies facing each other and enclosing at least one
chamber that can be filled with gas, the plies having surfaces
facing outwards, comprising a fabric dictating the outer and inner
structure of the air bag and on each surface facing outwards one
coating is disposed for strengthening and rendering the air bag
resistant to leakage.
2. The air bag as set forth in claim 1, wherein said coatings
comprise films keyed to the surfaces chemically, thermally or
mechanically.
3. The air bag as set forth in claim 1, wherein the coatings
comprise plastics-sheathed threads of the fabric plies.
4. The air bag as set forth in claim 1, wherein said textile sheet
fabric is a woven.
5. The air bag as set forth in claim 1, wherein said textile sheet
fabric is a knit or a non-woven fleece.
6. The air bag as set forth in claim 4, wherein said textile sheet
fabric comprises bicomponent yarns.
7. The air bag as set forth in claim 1, wherein said textile sheet
fabric is a thinned fabric, whose surface is laminated with a
coating or film.
8. A method of producing an air bag comprising two woven plies
facing each other and enclosing at least one chamber that can be
filled with gas, the plies having surfaces facing outwards, on
which coatings, laminates, films or covering layers are deposited
suitable for strengthening and/or rendering the air bag resistant
to leakage, comprising the steps: weaving the air bag on a weaving
machine controlled particularly by a Jacquard device, hot rolling
thermoplastics films on the surfaces, the keying points in the
fabric being flattened by pressure in thus forming a larger contact
surface for the films.
9. The method as set forth in claim 8, wherein said surfaces and/or
coatings, laminates, films or covering layers are prepared at least
in part by a corona treatment or by a plasma treatment or by
fluorination before roll application of the films.
10. The method as set forth in claim 8, wherein films of polyamide,
polyester, silicone, neoprene or polyurethane are laminated to said
surfaces.
11. The method as set forth in claim 8, wherein said surfaces are
provided with a film of silicone which is in turn treated with
fluorine gas.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation of PCT Application No.
PCT/EP03/05697 filed on May 30, 2003, which claims priority to
German Application No. DE 102 24 771.4-42, filed on Jun. 4, 2002;
both of which are incorporated by reference herein.
BACKGROUND AND SUMMARY OF THE INVENTION
[0002] The invention relates to an air bag comprising two plies of
a textile sheet fabric, the plies facing each other and enclosing
at least one chamber that can be filled with gas, the plies having
surfaces facing outwards, the invention also relating to a method
of producing such an air bag.
[0003] Air bag fabrics are in use whose technical properties are
dictated by the dense structure of the fabric. To attain the needed
strength and airtightness the fabric must be fabricated suitably
high set which because of the high material consumption results in
fabrication being expensive. Fully fabricated or one-piece woven
(OPW) air bags need to satisfy the crash withstanding performance,
in other words it is vital that the pressure in the air bag is
maintained for the critical duration, i.e. the air bags must not
leak. For this purpose such air bags are woven extremely dense,
major efforts being made to change the weave in the transition of
two-ply portions into single-ply portions in attaining, for
example, a high fabric tear strength or comb withdrawal force.
[0004] Since in many cases the air bag fabric made in this way
still fails to exhibit an adequate leakage resistance, additional
thin films are added in an expensive process with the sole
objective of sealing the fine pores of the fabric to achieve the
necessary leakage resistance. Air bags fabricated as such are, on
the one hand, because of the weaving method very expensive. On the
other, the expense of the air bags is further increased by the
complicated coating process. Because of its high density, finishing
such a fabric is a slow and thus cost-intensive process.
[0005] Known air bag fabrics have the further drawback that because
of the dense set and involving the slower weaving process the load
on the yarn is correspondingly higher. Thus, during the transition
in weaving the threads from the upper into the lower position and
vice-versa the threads rub against each other all the more often
and intensified because of the dense set, to the detriment of the
quality in weaving (capillary damage, fluffing, conglomerations,
thread breakage and the like) resulting in a high degree of
spoilage. Moreover, thread damage in weaving results in many cases
in downtime of the weaving machine, also due to machine speeds
needing to be increasingly higher causing a serious loss of
efficiency which in turn further adds to the already high costs of
production. Another drawback of the air bags as discussed is that
due to the high set and because of the correspondingly high fabric
thickness of the air bag fabric a certain packing volume of the
finished air bag needs to be assured in the folded condition.
Because of the high set the fabric or air bag becomes stiffer,
further adversely influencing working the fabric.
[0006] The present invention is based on the objective of producing
a low-cost air bag in avoiding or at least greatly diminishing the
drawbacks of prior art, as well as proposing a method for producing
such an air bag. This objective is firstly achieved by an air bag
as it reads from claim 1. This air bag in accordance with the
invention can now be fabricated significantly cheaper than air bags
as known from prior art. By arranging the coatings on the surfaces
of the fabric plies of the air bag facing outwards as suitable for
forming the leakage resistance and strengthening of the air bag,
the textile sheet fabric of the air bag can now be woven relatively
loosely. Strengthening the air bag in this sense is meant as
coating the air bag to achieve particularly high strength, leakage
resistance and keying to the fabric. The fabric itself is
responsible so-to-speak for forming the outer and inner structure
of the air bag and its at least one chamber, i.e. it not primarily
contributing towards leakage resistance and strength of the fabric
as handled namely by the coating e.g. also in the form of a film.
Now, because of this, the set of the fabric can be strongly
redimensioned. Thus, for instance, the single-ply portions in a
one-piece woven (OPW) can now be executed solid and tight in a
(simpler) plain weave instead of a panama weave as hitherto. This
greatly reduces the load on the fabric by shear forces at critical
transitions from single-ply to two-ply portions with the same weave
as achieved by the plain weave as proposed in this case, resulting
in a drastic reduction in the risk of the coating becoming detached
or damaged as arranged on the fabric, i.e. risk of leakage. By
satisfying the required airtightness the air bag in accordance with
the invention thus ensures the vital pressure withstanding
duration.
[0007] Another advantage materializes from the smoother surface of
the plain weave permitting better adhesion of the coating in
further reducing the risk of leakage. Because of the lower set and
the resulting higher output of the weaving machine, the air bag
fabric and one-piece wovens (OPW) in the shop and finishing can now
be produced and worked to advantage substantially cheaper. Due to
the fewer shed changes as well as due to the lesser attrition of
the threads against each other the load on the yarn material is
significantly reduced, resulting in a drastic reduction in
impairments (capillary damage, fluffing, conglomerations, thread
breakage and the like) in thus immensely enhancing product quality.
Since this involves the weaving machine being down far less because
of yarn impairment, efficiency is boosted substantially.
[0008] Yet another advantage of the air bag in accordance with the
invention materializes from the reduced packing volume in the
folded condition. The reduction in set as made possible by the
invention now makes it possible to reduce the cover factor and
result in a fabric with a softer feel with added flexibility. As a
result of this, the fabric coming from the weaving machine can now
be worked much better in the subsequent steps in the process.
Further features and advantages of the invention read from the
sub-claims.
[0009] The objective is further achieved by a method as it reads
from claim 8. For this purpose, particular mention is made to the
advantages of hot rolling thermoplastic films to the surfaces,
resulting in the keying points in the fabric being flattened by the
pressure in thus providing a more expansive receiving surface for
the roll-applied films. In other words, this relatively simple
trick now makes it possible to achieve a smoother surface for
better keying between coating and fabric. As a rule the surfaces of
e.g. of woven, knitted or netted textile sheet fabrics as
representing the aforementioned surfaces, for example, are not
smooth in structure but "bumpy", resulting in no continuous flat
contact surface being available for a coating, e.g. in the form of
a film. The threads of the textile sheet fabric merely "ripple"
from the surface thereof in a bumpy structure, whereby in a knit,
for example, the peaks of the loops protrude from the surface
whilst the valleys of the loops are located deeper in the knit.
[0010] It is known to coat textile sheet fabrics with fluids,
films, film-like materials or laminates and the like, serving e.g.
to enhance the resistance to ageing and/or leakage and/or to reduce
permeability and/or friction, etc. When such textile sheet fabrics
are overtaxed mechanically, hydraulically or pneumatically the key
between the textile sheet fabric and the coating is disrupted which
may even result in a total malfunction of the textile sheet
fabric.
[0011] In another advantageous aspect of the method in accordance
with the invention as it reads from claim 9, a low-cost method of
coating textile sheet fabrics, especially where wovens, air bag
wovens and air bags are involved in achieving a better adhesion
between the textile sheet fabrics and their coatings. A substantial
improvement in the adhesion of the textile sheet fabric is achieved
both by corona treatment and by plasma treatment as well as by
fluorination. In the corona and plasma processes as described and
discussed e.g. in German utility model DE 298 05 999 U1
electrostatic forces of attraction are activated to greatly enhance
the adhesion of the substances applied to the textile sheet fabric.
In fluorination of a textile sheet fabric, a reproducible, dry
chemical reaction takes place at the surface in which hydrogen
atoms are substituted by fluorine, creating a longer-active surface
permitting mechanical and chemical bonding.
[0012] In still another advantageous aspect of the method in
accordance with the invention the textile sheet fabric is coated
with a film of silicone whose surface facing away from the textile
sheet fabric is treated with fluorine gas. This fluorination
produces a near totally smooth surface practically cancelling any
silicone/silicone adhesion. This advantage is put to use
particularly for air bags to be folded, since it does away with the
need for a parting agent as required hitherto.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The invention will now be briefly explained in the following
by way of an example embodiment with reference to the drawing in
which:
[0014] FIG. 1 is a diagrammatic cross-section through a fabric ply
of an air bag in accordance with the invention.
[0015] FIG. 2 is a diagrammatic illustration of how thermoplastic
films are rolled on to a fabric ply for producing a textile sheet
fabric for the air bag in accordance with the invention.
DETAILED DESCRIPTION
[0016] Referring now to FIG. 1 there is illustrated a fabric
including weft threads 6 and (not shown true to scale) warp threads
7. Indicated are so-called keying points 2 to which a film 1
optimized as to adhesion, resistance to leakage and strength is
applied to a fabric 3 formed by weft and warp threads 6 and 7
respectively. Due to the fabric 3 being compressed by a pair of nip
rollers 4 as shown in FIG. 2 the warp threads 7 are squeezed
together so that they become elliptical cross-sectionally. Likewise
evident from the arrangement as shown in FIG. 1 simply
diagrammatical is how the keying "points" 2 become flattened
between film/coating and fabric.
[0017] Referring now to FIG. 2 there is illustrated a pair of nip
rollers 4 between which the film 1 as cited above and the backing
fabric 3 thinned in the thread densities is guided and keyed. The
resulting key of film/coating and fabric is achievable, chemically,
thermally or mechanically, resulting in so-to-speak a
textile-strengthened plastics surface 5 which can be additionally
compounded by making use of bicomponent yarns. In a loose fabric
setting the ondulation of the fabric is less. The keying points 2
of the textile-strengthened plastics surface 5 are flattened by the
pressure in rolling and offer a larger contact surface for the film
1.
[0018] The air bag may also be configured as it reads from claim 3,
whereby the advantages as discussed with reference to claim 1 are
likewise provided. By thermally treating the air bag after weaving
the necessary leakage resistance and strength are attainable due to
cross-linking of the components of the plastics sheathing the
threads of the fabric plies.
* * * * *