Land vehicles – Wheeled – Attachment
Reexamination Certificate
2002-01-15
2004-06-08
Ilan, Ruth (Department: 3616)
Land vehicles
Wheeled
Attachment
C280S728300
Reexamination Certificate
active
06746042
ABSTRACT:
TECHNICAL FIELD
The invention relates to a method of producing a vehicle interior lining, especially a dashboard having a carrier part and, attached to the carrier part, a gas bag module containing a gas bag carrier and a gas bag that has a folded package section. The invention also relates to a vehicle interior lining.
BACKGROUND OF THE INVENTION
Vehicle interior linings are manufactured in the largest possible sections in order to save assembly costs. This also applies to the dashboard that has to contain a passenger-side gas bag in modern vehicles in order to protect the passenger against injury in case of an accident.
In order to make the interior of the vehicle more comfortable for an occupant, in some cases, parts of the vehicle interior lining, also including the dashboard, are covered with a soft, resilient foamed material. The foam layer alone is not dimensionally stable enough, as a result of which it is applied onto a carrier part that consists, for example, of a harder injection molded plastic or of pressed materials, and that defines the shape of the vehicle interior lining. Until now, a gas bag module, for example, for a passenger-side gas bag, has been mounted under the carrier part so that the outlet opening of the gas bag is covered by a section of the carrier part. This section of the carrier part, which can be configured, for instance, as a conventional flap, can be dispensed with if the carrier part is covered with a foam layer, since the dimensional stability of the foam layer that is applied onto the carrier part is sufficiently high to create an esthetically pleasing surface that protects the gas bag underneath from being damaged. This gives rise to the decisive advantage that it is possible to dispense with the otherwise necessary separate covering flap, which is made of a rigid plastic material and is attached to the carrier part either by means of complex hinge mechanisms or else which has to have predetermined breaking points that are complicated to create.
U.S. Pat. No. 5,711,545 describes such a vehicle interior lining. At the desired place, the carrier part forms a receptacle for the gas bag module in the form of an depression, the folded gas bag being placed in such a way that it fills the depression. A flexible protective layer, which can be, for example, a paper-based product and which does not contribute to the stability, is placed over the gas bag. A plastic layer, which forms the visible part of the lining and makes a one-piece transition to the cover of the gas bag module, is foamed over this flexible protective layer, which is supposed to prevent the foamed material from penetrating into the gas bag module. For this purpose, the gas bag module is premounted on the carrier part, covered with the flexible protective cover, inserted into a foaming mold and foamed. During the foaming process, it can happen that the folded gas bag package is compressed by the pressure that prevails in the foaming mold. When the pressure subsides, the gas bag package decompresses again, as a result of which the surface of the foam layer can be detrimentally affected.
Therefore, the object of the invention is to propose a method with which such a detrimental effect cannot occur. Moreover, a vehicle interior lining, especially a dashboard, is to be provided that allows an especially fast deployment of the gas bag, whilst nevertheless, only small forces are transmitted to the vehicle occupant by the unfolding gas bag.
BRIEF SUMMARY OF THE INVENTION
The method according to the present invention of producing a vehicle interior lining, especially a dashboard, provides that the lining has a carrier part and, attached to the carrier part, a gas bag module containing a gas bag carrier and a gas bag that has a folded package section (package-like folded section of the gas bag). The method comprises the following steps:
the gas bag, together with its package section, is placed into a gas bag receptacle that is formed on the gas bag carrier and that has an outlet opening for the gas bag;
the outlet opening is at least partially closed in an area of the package section by a rigid means;
an outside surface of the carrier part is foam-encapsulated with a plastic layer in a state in which the gas bag module is connected to carrier part.
By means of the rigid means, a compression of the package section of the gas bag is avoided during the foaming process so that no impairment of the surface of the foam layer can occur.
The carrier part advantageously has an opening for the unfolding of the gas bag, and the gas bag as well as the gas bag carrier lie in the projected area of the opening, i.e. in the opening or below it. Therefore, the foam layer is foamed onto the gas bag module directly, that is to say, without a stable intermediate layer.
The means preferably has such a strength that it is not substantially deformed by the pressure that is generated during the foaming process, so as to avoid a compression of the package section. The pressure in the foaming mold used is preferably between 2 and 10 bar, and especially preferably between 3 and 5 bar. Conventional foaming machines can be employed in this pressure range.
The deformation of the means is advantageously less than 5 mm and especially preferably less than 3 mm. A compression by this amount can be compensated for in the foam layer itself.
In order to prevent foam from penetrating into the gas bag module and in order to protect the gas bag module from environmental effects, a plastic foil is preferably arranged directly over the means before the carrier part is foam-encapsulated.
The method is especially well-suited for use with a gas bag carrier in which the gas bag receptacle is formed continuously along the edge of a middle plate of the gas bag carrier. Such a gas bag carrier can be used for modules that are particularly flat in shape and that have a relatively large lateral expansion, which is desirable for passenger gas bags. The middle plate is preferably flush with the outer surface of the carrier part and offers the necessary support for the foam layer in this area of the opening.
In order for the means not to interfere with the deployment of the gas bag out of the outlet opening of the gas bag receptacle during the unfolding of the gas bag, the means preferably has such a low strength that it frees the outlet opening in response to a force that is being exerted on the means by the unfolding gas bag when the gas bag module is activated. This can be achieved in that predetermined breaking points are provided at a suitable place in the means. Since the means can have much smaller dimensions and a lower weight than a conventional covering flap, the risk of injury to a vehicle occupant is low.
In a preferred embodiment of the method according to the invention, after the gas bag has been placed into the receptacle, the outlet opening is constricted in that the receptacle is compressed. In this case, the means is formed by the edge sections of the gas bag receptacle, which cause a constriction. No additional parts have to be used, which reduces the costs. Since the gas bag expands to a certain degree into the sections of the receptacle when it unfolds, thus freeing the outlet opening again, no loose parts are created that could be hurled into the vehicle interior. It is also possible for the gas bag receptacle to be compressed all the way down to just a narrow gap through which the gas bag can be pulled out of the gas bag receptacle when the gas bag unfolds. Thus, no additional force has to be used to free the outlet opening.
The invention also relates to a vehicle interior lining that is preferably made by a method according to the invention. In a preferred embodiment of such a vehicle interior lining, the means is a frame with a U-shaped profile that surrounds the gas bag receptacle, the open side of the U-shaped profile facing the inside of the frame and one leg of the U-shaped profile at least partially closing the outlet opening. After the package section of the gas bag is placed into the gas bag receptacle, the fra
Dannenhauer Reiner
Debler Jens
Hägele Bernd
Lang Norbert
Ritter Philipp
Ilan Ruth
Tarolli, Sundheim Covell & Tummino L.L.P.
TRW Occupant Restraint Systems GmbH & Co. KG
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