U.S. patent application number 09/751852 was filed with the patent office on 2001-11-15 for gas bag module.
This patent application is currently assigned to TRW Occupant Restraint Systems GmbH & Co.KG. Invention is credited to Ellerbrok, Norbert.
Application Number | 20010040362 09/751852 |
Document ID | / |
Family ID | 8083653 |
Filed Date | 2001-11-15 |
United States Patent
Application |
20010040362 |
Kind Code |
A1 |
Ellerbrok, Norbert |
November 15, 2001 |
Gas Bag Module
Abstract
The invention relates to a gas bag module, comprising a module
cover which has at least one opening flap movable upon activation
of the module. An axis is provided relative to which the opening
flap moves when it is opened, and a tether is provided between the
at least one opening flap and a part of the gas bag module. In an
open condition of the module cover the opening flap is fixed on the
one hand to the module by means of the tether and on the other hand
is fixed to the module cover via the axis. The axis and the tether
are arranged with respect to the opening flap in such a manner and
the opening flap has such a strength that its geometry is changed
by the tether when it is swivelled open so that the opening flap
moves outwardly by a smaller amount than without the tether.
Inventors: |
Ellerbrok, Norbert;
(Rudersberg, DE) |
Correspondence
Address: |
TAROLLI, SUNDHEIM, COVELL, TUMMINO & SZABO L.L.P.
1111 LEADER BLDG.
526 SUPERIOR AVENUE
CLEVELAND
OH
44114-1400
US
|
Assignee: |
TRW Occupant Restraint Systems GmbH
& Co.KG
|
Family ID: |
8083653 |
Appl. No.: |
09/751852 |
Filed: |
December 29, 2000 |
Current U.S.
Class: |
280/728.3 ;
280/743.2 |
Current CPC
Class: |
B60R 21/21656 20130101;
B60R 21/216 20130101; B60R 21/2155 20130101; B60R 2021/21543
20130101 |
Class at
Publication: |
280/728.3 ;
280/743.2 |
International
Class: |
B60R 021/20; B60R
021/16 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 30, 1999 |
DE |
299 22 987.4 |
Claims
1. A gas bag module, comprising a module cover which has at least
one opening flap movable upon activation of said module, an axis
being provided relative to which said opening flap moves when it is
opened, and a tether being provided between said at least one
opening flap and a part of said gas bag module, in an open
condition of said module cover said opening flap is fixed on the
one hand to said module by means of said tether and on the other
hand is fixed to said module cover via said axis, said axis and
said tether being arranged with respect to said opening flap in
such a manner and said opening flap having such a strength that its
geometry is changed by said tether when it is swivelled open so
that said opening flap moves outwardly by a smaller amount than
without said tether.
2. The gas bag module as claimed in claim 1, wherein between said
axis and said tether said opening flap has a predetermined bending
point, about which said opening flap is bent when opened.
3. The gas bag module as claimed in claim 1, wherein a plurality of
predetermined bending points is provided.
4. The gas bag module as claimed in claim 2, wherein a film hinge
is provided, said opening flap being bent about said film
hinge.
5. The gas bag module as claimed in claim 1, wherein said axis is a
stationary swiveling axis.
6. The gas bag module as claimed in claim 5, wherein said swiveling
axis is formed by said film hinge.
7. The gas bag module as claimed in claim 5, wherein in said bent
condition said opening flap swivels outwardly about said axis.
8. The gas bag module as claimed in claim 2, wherein said bending
point and said tether are arranged with respect to each other such
that an outer edge of said opening flap describes a substantially
elliptical path when said flap is opened.
9. The gas bag module as claimed in claim 1, wherein it has a gas
bag which is deployed such that it presses onto said tether and
effects a geometric deformation of said opening flap.
10. The gas bag module as claimed in claim 9, wherein at said gas
bag a deployment limiting means is provided, which at the beginning
of a deployment process directs a portion of said gas bag towards
said tether, in order to contact the latter.
11. The gas bag module as claimed in claim 10, wherein said
deployment limiting means is a strap wound around said folded gas
bag, which strap will tear during said deployment process.
12. The gas bag module as claimed in claim 1, wherein said tether
is so short that a force which leads to a change in the geometry of
said opening flap is already exerted on said opening flap via said
tether when said deployment opening is open for 20 to 50
percent.
13. The gas bag module as claimed in claim 1, wherein an emblem
mounted on an outside of said opening flap is provided, said tether
being mounted to an inner side of said opening flap in a region of
said emblem.
14. The gas bag module as claimed in claim 1, wherein an emblem
mounted on an outside of said opening flap is provided, said tether
being incorporated in said opening flap in a region of said emblem.
Description
TECHNICAL FIELD
[0001] This invention relates to a gas bag module comprising a
module cover.
BACKGROUND OF THE INVENTION
[0002] Known module covers usually swing to the outside when they
are opened, the opening flap having a relatively large swiveling
radius. This swiveling radius might possibly hurt the occupant
sitting too close to the gas bag module, in particular in the case
of a so-called out-of-position (OOP) sitting posture of the
occupant or in case of a second crash.
BRIEF SUMMARY OF THE INVENTION
[0003] The invention provides a gas bag module which has an opening
flap that moves less far toward the occupant when it is opened.
This is achieved in a gas bag module which comprises a module cover
which has at least one opening flap movable upon activation of the
module. An axis is provided relative to which the opening flap
moves when it is opened, and a tether is provided between the at
least one opening flap and a part of the gas bag module. In an open
condition of the module cover the opening flap is fixed on the one
hand to the module by means of the tether and on the other hand is
fixed to the module cover via the axis. The axis and the tether are
arranged with respect to the opening flap in such a manner and the
opening flap has such a strength that its geometry is changed by
the tether when the opening flap swivels open. The opening flap
moves outwardly, i.e. toward a passenger compartment by a smaller
amount than without the tether. In the gas bag module according to
the invention it is the function of the tether to change the
geometry of the module cover. This is achieved in that a force,
acting on the opening flap e.g. by the deploying gas bag or by some
other means, produces a counterforce in the axis and in the tether.
The opening flap is preferably bent or even kinked by influencing
these forces and counterforces, and in this condition it is moved
away from the deployment opening for the gas bag. Caused by the
change in the geometry of the opening flap, the latter requires
less space during the opening process. When the axis for instance
is a pure swiveling axis, the opening flap will have a smaller
swiveling radius than without the tether. The term swiveling radius
may also be inaccurate in this context, because when the opening
flap changes its geometry during the opening movement, any path of
movement can be generated for the relevant outer edge of the
opening flap.
[0004] To ensure that these paths of movement can possibly be
predetermined, one or more bending or kinking points in the opening
flap have been predefined, which can for instance be produced by a
kind of film hinge or some other weakened portions in the
cover.
[0005] In accordance with the preferred embodiment, the axis is a
stationary swiveling axis, which is formed by a film hinge. This
formation of the axis is very inexpensive.
[0006] The gas bag will usually urge the opening flap, which is
formed integrally at the module cover, to the outside and tear open
the module cover. It may possibly deliberately press or move the
tether such that it causes the geometric deformation of the opening
flap. To ensure that this process, namely tearing open, moving the
opening flap and the large enough introduction of force to cause
the change in geometry, is effected in a predeterminable way, one
design of the invention provides a deployment limiting means at the
gas bag, which acts at the beginning of the deployment process and
directs portions of the gas bag to predetermined points of the
tether. The deployment limiting means may for instance be a strap
constricting the folded gas bag, which strap will tear during the
deployment process, but at the beginning of the deployment process
predetermines the initial deployment direction.
[0007] In the preferred embodiment, the tether is so short that it
exerts a restraining force on the opening flap, which restraining
force leads to the change in the geometry of said opening flap,
when the deployment opening for the gas bag is open for 20 to 50
percent. This is based on the opening cross-section. It should thus
be ensured that the opening flap is bent or kinked already in the
initial phase of the opening movement.
[0008] In the preferred embodiment, the module cover has an emblem
on its outside, the tether being mounted to the inner side of the
covering flap in the region of the emblem or so as to be
incorporated therein; thus, the tether being able of directly
retaining the heaviest part of the cover.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 shows a bottom view of a module cover as part of the
gas bag module according to the invention;
[0010] FIG. 2 shows a stylized cross-sectional view of a gas bag
module according to the invention, which has a module cover as
shown in FIG. 1;
[0011] FIG. 3 shows a stylized cross-sectional view of a second
embodiment of the gas bag module according to the invention, with
the cover closed;
[0012] FIG. 4 shows the gas bag module in accordance with FIG. 3,
shortly after the beginning of the opening process;
[0013] FIG. 5 shows the gas bag module in accordance with FIG. 3
with a farther open opening flap; and
[0014] FIG. 6 shows the gas bag module in accordance with FIG. 3
with completely open opening flap.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] FIG. 1 represents a module cover for a steering wheel gas
bag module. The module cover 3 has a front wall 5, which faces the
driver, and a surrounding side wall 7. On the outside of the front
wall 5 an emblem 9 is mounted, which is represented in broken
lines. On the rear side, a plurality of rivets 11 for fixing the
emblem 9 can be seen. The module cover has a plurality of opening
flaps 13 to 25 defined by tear lines (weakened portions in the
module cover), which are provided with the reference numeral 27. At
the transition of the opening flaps 13 to 25 to the side wall 7
film hinges 31 are provided, which serve as axes, more precisely as
swiveling axes.
[0016] The opening flap 17 is the one to which the emblem 9 is
fixed and which by no means should come in contact with the
occupant. The opening flap 17, which extends from the two parallel
portions of the tear line 27 up to the side wall 7, has a
predetermined bending or kinking point 43 parallel to the
associated axis 31 of the opening flap 17 in the area between the
side wall 7 and the emblem 9, which kinking point has been formed
by a weakened portion of the opening flap 17 in a line-shaped
area.
[0017] The rivets 11 not only serve to mount the emblem 9 at the
front wall 5, but also a tether 51, which is shown in FIG. 2, at
the opening flap 17. FIG. 2 furthermore illustrates the gas
generator 61 and the folded gas bag 63 as parts of the gas bag
module. In the area below the tear line 27, i.e. at the transition
between the opening flaps 13, 15 and the opening flap 17, the gas
bag 63 has a strap 65 surrounding it, which strap acts as
deployment limiting means and will tear during the deployment
process, as will be explained below. In the left-hand half of the
gas bag module represented in FIG. 2, several phases during the
opening movement of the opening flap 17 are shown.
[0018] Upon activating the gas generator 61, gas will enter the gas
bag 63 and the gas bag will unfold. The strap 65 divides the gas
bag 63 in two halves, so that at the beginning of the deployment
process these two halves will unfold separately, namely toward the
center of the respective opening flap 17 or 13, 15. Due to the
pressure applied onto the opening flaps the front wall 5 will tear
in the region of the tear lines 27, and the opening flaps are
formed. At the beginning, the opening flap 17 swivels as a rigid
unit about its swiveling axis 31 toward the passenger compartment,
with respect to FIG. 2 in upward direction. After a small swiveling
angle, not even half the deployment opening 67 is open, it already
happens that the gas bag exerts such a force on the tether 51 that
the opening flap 17 kinks in the region of the kinking point 43.
The opening flap 17 then swivels further in anti-clockwise
direction, but this swivel movement takes place in the kinked
condition. Due to such kinking, the opening flap 17 moves
outwardly, i.e. toward the driver or the passenger department P by
a smaller amount r than without kinking. When the opening flap 17
is opened about the swiveling axis 31, the swiveling radius r
thereof is thus smaller in the present case than the amount (in the
form of the swiveling radius R) by which the opening flap 17 would
move without kinking during the opening movement. This means that
the hazard potential for the occupant is also smaller. The location
of the swiveling axis 31, the length of the tether 51 and its
attachment to the opening flap 17 on the one hand and to the gas
bag module on the other hand (e.g. to the module cover or a housing
part such as a gas generator mounting plate) as well as the
direction of deployment of the gas bag 63 and the stability of the
opening flap must be matched with each other such that the opening
flap 17 is kinked during the opening process and thus undergoes a
change in its geometry.
[0019] A kinking of the opening flap need not necessarily be
effected, and it is possibly sufficient when the same is bent.
Moreover, the path of movement described by the outer end of the
opening flap 17 during the opening process is not a circle, but
preferably a kind of elliptical path. In this case, the reference
numeral r indicates the largest distance which a portion of the
opening flap 17 has from the swiveling axis 31 during the opening
process. In the course of the further deployment of the gas bag 63
the strap 65 will finally tear, and the gas bag can fully deploy
and emerge from the then completely exposed deployment opening
67.
[0020] In the embodiment shown in FIGS. 3 to 6, a plurality of
kinking points is provided, i.e. between the kinking point 43 and
the swivel axis 31 there is defined a second kinking point 81 in
the opening flap 17 in the region of the transition between the
front wall 5 and the side wall 7. Due to the additional kinking
point 81 is possible that the opening flap 17 is moved even less
far toward the occupant, when it is opened. The individual phases
of the opening movement are represented in FIGS. 4 to 6. With this
embodiment, too, portions like the halves of the gas bag 63
described above with reference to FIG. 2 exert forces on the tether
51 at predetermined times at predetermined points, which forces
lead to the kinking of the opening flap 17. As is shown in FIG. 4,
the kinking point 81 is practically not employed and the kinking
point 43 is hardly employed at the beginning of the opening
process, so that the opening flap 17 swivels to the outside about
the swiveling axis 31 virtually without a change in geometry. When
the deployment opening 67 opened less than 50 percent of the
completely open state (FIG. 6), a kinking at the kinking point 43
can clearly be recognized (FIG. 5).
[0021] The amount by which the opening flap provided with two
kinking points moves toward the occupant can again distinctly be
reduced by this embodiment. Moreover, it is not absolutely
necessary that the gas bag presses onto the tether 51 during
deployment and leads to the kinking of the opening flap 17. The
tether 51 may just as well be very short, so that the outer edge of
the free end of the opening flap 17 cannot completely swivel to the
outside, as is represented in FIG. 2 with reference to the radius
R. In this case, the gas bag would directly press onto the opening
flap 17 and kink the same between its supports (tether 51 and
swiveling axis 31).
* * * * *