The present invention relates to a method of fastening
an airbag to a structural member of a motor vehicle, a motor vehicle, as well as
an airbag for a curtain airbag module.
Methods for fastening airbags to a structural member of
a vehicle are known from the prior art. US 6 073 961 teaches an airbag arranged
in a container, fastened to the structural member of a vehicle by a screw. During
the deployment of the airbag, the screw protrudes at least partly out of the container,
so that the airbag is securely connected to the structural member on the basis of
its connection to the container. The problem is that the airbag is connected to
the structural member prior to its installation by a hanger element, for instance
a container surrounding it. In this manner the airbag is initially to be mounted
on this hanger element, then subsequently to be fastened to the vehicle structure.
The result is an extremely cost-intensive installation, combined with an increased
time for the assembly of the unit comprising the airbag and the fastener.
JP-A-2002/104127 discloses a fixing structure of an airbag
(11) comprising a plurality of mounting parts (14) formed on an upper edge of the
airbag body. The airbag (11) is fixed to the vehicle body panel (13) by means of
a knob part (16, 19, 22) which is rotated into the locking member (17,20,23) through
the locking hole (15) provided within said mounting parts (14). According to this
closest prior art showing the features of the preamble of claim 1, the airbag body
is fitted onto the vehicle structural member by means of a locking member and a
knob, i.e. a fastener.
The present invention provides an airbag fastened to a
structural member a motor vehicle, and an airbag for a curtain airbag module, which
ensures a simple, cost-effective and secure mounting of an airbag to a structural
- Fig.1 is a side view of an airbag in a non-inflated state.
- Fig.2 is a sectional view of a preferred embodiment of the airbag according
to the invention in an inflated state, attached to a structural member of a vehicle.
An airbag module for a curtain airbag is shown in Fig.1.
An airbag 2 is in a non-inflated state. An inflator 4 is connected to the airbag
to supply the airbag 2 with gas during its deployment. During the inflation of the
airbag 2, the airbag deploys downwards, e.g. before the side windows of the vehicle.
The airbag 2 can be arranged at any other location in a vehicle, e.g. in the region
of the dashboard or in the knee or foot region. The airbag 2 can, in accordance
with the invention, also be used in applications other than in motor vehicles, e.g.
in any other vehicles, such as trains or aircraft.
In the fastening regions of the airbag 2, in which the
airbag 2 is to be connected with a structural member 12 of the structural member
of a vehicle, several straps 6 are located. The fastening region comprises a region
of the airbag in which a connection or a fastening to the structural member or an
element thereof is located. The straps are made out of essentially the same material
as the airbag 2. The fastening regions are presently foreseen along the longitudinal
extent of the airbag 2, but can also, or additionally, be arranged on its front
sides. The straps 6 can be designed such that two layers of the airbag 2 are stitched
and/or glued together in such a manner that in this region cannot be inflated with
gas. The straps 6 can also be sewn or welded to the airbag. To increase their strength,
the straps 6 can also be folded several times, sewn and/or welded. In addition or
alternatively, at least the fastening region can comprise a coating or impregnation
with a stiffening compound to increase resistance.
Within the straps 6 are portals 8, through which in an
assembled state parts of the structural member of a vehicle or hanger elements 10
for the fastening of the airbag 2 can extend along the latter. The portals 8 are
openings of polygonal shape, and are adapted so that an at least partly positive
locking is achieved with the hanger elements 10. This way it is avoided that the
airbag 2 slips from the hanger elements 10 during installation. Due to a polygonal
design of the portals 8 and the hanger elements 10 a twisting of the airbag 2 during
installation is avoided. In addition to this, eyelets could be located on the portals
8 to improve their resistance to wear.
Each portal 8 is a hole or opening in the airbag material,
made for example by stamping. In other words the airbag does not comprise any additional
fastener (i.e. fastener the airbag to or hanging the airbag from the structural
member, and which absorb a force during the deployment of the airbag or airbag),
but is immediately connected or brought into engagement with the hanger element
of the structural member, merely by portals located in the airbag material. According
to the invention additional secondary fasteners (e.g. clips, pins, double-sided
adhesive tape, etc.) can be foreseen which, despite essentially not absorbing any
force during the deployment of the airbag, suitably position the packed airbag or
the packed module during the mounting, e.g. for it not to come into contact with
a cover (e.g. a vehicle roof lining). The cover contributes to the secure positioning
of the airbag, wherein the cover can also be advantageously fastened to the fastener
on the vehicle structural member. In this manner a direct connection between the
airbag material and the structural member or hanger element is created, so that
in the fastening region the airbag material essentially absorbs the forces acting
upon the airbag. Due to the immediate arrangement of the airbag to at least one
hanger element, an advantageously simple and cost-effective fastening is achieved,
since no additional clips, interface structure or other connection elements are
necessary and the assembly time is significantly reduced. The immediate arrangement
of the airbag to the at least one hanger element is thus carried out by direct contact
or connection of the airbag material to the hanger element, so that no further additional
elements are required in or on the airbag or airbag material.
The fastener is 14 secured to the side of the hanger element
10 distal from the structural member, to secure the airbag 2 in its position between
the structural member and the fastener. By providing a fastener in this position,
the airbag can be securely held on the hanger element between the frame or the structural
member and the fastener, so that an advantageously operationally safe airbag or
airbag is provided.
The area of the portals 8 is larger than the cross section
of the hanger elements 10. In this way the airbag can be assembled on the hanger
element by a simple or smooth sliding or pulling over onto the hanger element.
The area of the portals 8 can be smaller or equal to the
cross section of the hanger elements 10, so that the portals or the airbag must
be tightly slid onto the hanger elements, so that a sufficient preliminary attachment
can be ensured.
The straps 6 are arranged on at least one border region
of the airbag. In this case the straps are made of the same material as the airbag
2, i.e. they are part of the airbag. As a result, the airbag can be hooked into
the present hanger elements with slightly larger, suitable straps without additional
fastener. The portals 8 are may be arranged in accordance with a gripping position.
It is thus advantageously possible to arrange the straps 6 and the hanger elements
10 in such a manner that on these one or several handles for the passenger compartment
can be fastened by the fastener. The portals 8 may be arranged in pairs with the
fastening elements 14 extending through the portals arranged in pairs and the fastener
14 is a handle for gripping by a vehicle occupant.
This type of fastening is shown in Fig.2. Through the portal
8 of the strap in this at least partly deployed airbag 2, a hanger element 10 extends,
and is connected with a structural member 12 of a vehicle or is itself a part of
the latter. The hanger element 10 has a polygonal cross section that is complementary
to, and essentially corresponds to the shape of the portal 8. The hanger element
10 may be a fastening block for a handle. In this case the airbag 2, in the region
of the portals 8, can be directly or immediately slid onto the hanger element 10
without further fastener, positioned between the airbag 2 and the hanger element
10. Additional secondary fastener (not shown) can be foreseen, ensuring a correct
positioning of the packed airbag 2. In contrast to the hanger element 10, these
secondary fastener (e.g. clips, pins, adhesive tape) do not absorb any significant
forces during the deployment of the airbag 2, but rather are used for the positioning
of the airbag 2 in a packed state, e.g. to avoid undesired contact with a cover.
To ensure the positioning of the airbag 2, a fastener 14
is arranged on the side of the hanger element 10 turned away from the structural
member 12, to secure the airbag 2 in its position between the structural member
12 and the fastener 14. The fastener 14 may extend beyond the hanger element 10,
i.e. it extends beyond the cross sectional surface of the hanger element 10 on at
least one side. The fastener 14 can be a screw, bolt or rivet, which extends through
the hanger element 10 and engages the structural member 12 and may comprise at its
side turned away from the structural member 12 a (plain) washer to ensure the positioning
of the airbag 2. Alternatively the fastener 14 can also be a locking element, which
can be locked or brought into engagement with the hanger element 10 and/or the structural
member 12. Due to the fastener 14, a casing or cover 16, e.g. a roof lining cover
or a dashboard cover, is secured to at least one part of the airbag 2 between the
hanger element 10 or the structural member 12 and the fastener 14, so that this
also contributes to the positioning and securing of the airbag 2.
At least one hanger element 10 may be essentially hook-shaped
and the step of the arrangement of the airbag on the at least one hanger element
is carried out by hooking the airbag onto the structural member of the vehicle by
placing at least one portal 8 in around the at least one hanger element. In this
case the at least one hanger element is essentially shaped like an upwards pointing
hook, so that the airbag can be hooked into the hanger elements. In this case the
corresponding portals on the hanger elements can show a slight allowance on the
hanger element, so that a hooking of the airbag can be facilitated, wherein a sufficient
preliminary attachment is achieved by the hook-shaped design of the hanger elements.
The step of the immediate arrangement of the airbag to
the at least one hanger element of the structural member is carried out by interlocking,
that is to say sliding of the airbag or the straps onto the hanger elements. To
this effect the hanger element is designed in such a manner that the airbag can
be slid onto it in a simple manner, wherein assembly costs can be advantageously
reduced. The hanger element is essentially polygonal. Due to the interlocking, by
sliding of the airbag or the portals onto the hanger elements, a sufficient preliminary
attachment can be advantageously ensured, since in this case the portals of the
airbag are dimensioned in such a manner that they are essentially slid onto the
tightening elements in a "tight" manner (i.e. with a slight interference fit).
Due to the direct sliding of the airbag 2 or its portals
8 onto the hanger element 10 without additional third means connected to the airbag
2, an advantageously simple and cost-effective method for fastening an airbag to
a structural member of a vehicle can be achieved.
In a further embodiment, the method for fastening an airbag
to a structural member comprises the step of arranging a cover between the fastener
and at least one part of the airbag. A cover, such as for instance a roof lining
cover, can in this case also be fastened to the vehicle structural member by the
fastener. In this case a smaller number of or else no additional fastener are required,
wherein assembly costs and times can be reduced. In addition, by the cover arranged
above the airbag (as seen from the vehicle inside), the latter can also be secured
in its position.
The straps 6 may advantageously be made out of the same
material as the airbag. In other words the straps or the region of the portals form
an integral part or one unit with the airbag. The straps may be strengthened by
seams, welds, glues and/or coatings to improve resistance, so that a tearing of
the portals during the activation of the airbag can be prevented. The fastening
region or the straps may be indicated by a seam or a glued part in the airbag. In
this way a region of the airbag does not inflate with gas during the inflation of