Land vehicles – Wheeled – Attachment
Reexamination Certificate
1998-07-01
2001-01-09
English, Peter C. (Department: 3619)
Land vehicles
Wheeled
Attachment
C280S728100
Reexamination Certificate
active
06170870
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to an airbag and a method for folding airbags.
BACKGROUND OF THE INVENTION
In airbag modules the airbags are arranged in a folded state in their rest position in the area of a gas generator. For this it is necessary inter alia to arrange the folding and positioning in the area of the gas generator so that after the gas generator is detonated the airbag unfolds easily unhindered and can be rapidly filled with gas.
The so-called continuous fan-fold method of folding is already known. Here the spread-out airbag is placed concertina-like in folds starting from a central (imaginary) centre line and extending each side of this line so that an oblong roughly rectangular strip is produced. Then this strip itself is folded several times in its longitudinal direction by placing the ends over the middle area or by rolling in the ends. An example is shown in EP 0 614 786 A1.
The drawback with this type of folding is that after detonation of the gas generator and with the gas pressure which thereby arises in the centre of the airbag the outer folds which have been formed by cross-folding hinder the unfolding of the longitudinal folds and at first the cross folds which have been turned in last and whose outer areas can only be reached with difficulty at first by the gas pressure arising in the centre have to unfold first before the longitudinal folds which were the first to be folded when collapsing the airbag can themselves be unfolded.
Furthermore there is the drawback that the airbags folded in this way have still to be folded by hand at least in part.
From DE 41 38 645 A1 an airbag is known which is first folded in zig-zag fashion into a number of longitudinally aligned folding paths on opposite side areas of the airbag. The airbag is then folded in zig-zag fashion into a number of transversely-aligned folding paths from the rear end of the airbag outside of the socket area towards the front end of the airbag.
Furthermore an airbag is known from DE 43 43 026 A1 which is first turned in to the inside from the sides. The centers of the turned-in parts are then drawn to the outside. The airbag prefolded in this way is again folded cross-wise to the first folding direction.
Even with these types of folding there is the disadvantage that the airbags can only be mechanically folded at extremely high cost and that the folds intersect so that they impede each other as they unfold.
It is also known from DE 44 22 276 A1 to fold the airbag along main fold lines which run at least in part along closed paths round an imaginary centre on the substantially empty spread-out airbag. Thus starting from an imaginary centre of the spread-out airbag a type of concentric zig-zag or concertina-type folding is produced. The main fold lines preferably form concentric circles or ellipses.
With the airbag folded in this way, folding individual sections of the airbag over each other is no longer necessary. Furthermore by gathering up the airbag it is possible to collapse the airbag into a compact unit. The airbag folded in this way can then unfold quickly and unhindered in all directions once the gas generator is detonated and folding can also be carried out substantially automatically.
SUMMARY OF THE INVENTION
The object of the present invention is in the case of a straight-line concertina-type folding of an airbag to achieve faster unfolding after detonation of the gas generator and to achieve automatic folding of the airbag.
In the case of an airbag for an airbag module where the airbag is folded in the rest state concertina-like in the area of a gas generator, the airbag packet which is formed by the concertina-type folds is additionally bent down at least once in a plane which runs perpendicular to the fold surfaces and parallel to the fold edges. More particularly the airbag packet formed by the concertina type folds is additionally bent down at least once in a plane which runs in relation to the concertina type folds perpendicular to the fold surfaces, parallel to the two planes in which each lower and upper fold edges lie, and parallel to the front side of the airbag module facing the occupant in the installed state.
The airbag packet is thereby folded, starting from two opposite sections relative to the gas generator, repeatedly in the direction of the ends of the airbag packet.
In a preferred embodiment the airbag packet is folded repeatedly so that a concertina-type fold is likewise provided in the second folding direction.
An airbag folded in this way can be easily unfolded in the same way as an airbag which is folded concentric according to the gathered folding mentioned above, since no section of the airbag is folded over another. Furthermore there is the advantage that only one layer of airbag lies above the gas generator. During inflation of the airbag this layer is moved in the direction of the vehicle occupant and draws the folds of the airbag packet behind it. The same favorable unfolding is reached here as with gathered folding. As opposed to this in the case of other known types of folding where the folded packet lies above the gas generator the airbag is pressed out during inflation.
This folding can be used with particular advantage in the case of a driver airbag module where the airbag is folded round a pot-shaped gas generator wherein the height of the folded airbag packet corresponds roughly to the height of the gas generator. Also in this embodiment the same advantages are produced as in the case of an airbag with concentric gathered folding.
In one embodiment for a driver airbag the airbag is bent down on both sides on either side of the gas generator. The strips of the concertina type folded airbag packet thereby formed are stored in the area of the spokes of the steering wheel.
In one embodiment where a tubular gas generator is mounted inside or underneath the airbag the airbag is folded at least approximately parallel to the longitudinal axis of the tubular gas generator. The strips of the folded airbag protruding over the ends of the tubular gas generator are bent down in opposite directions and placed against the middle sections or against the centre part of the airbag.
In one embodiment where the airbag is arranged asymmetric relative to a tubular gas generator the airbag folded at least approximately parallel to the longitudinal axis of the tubular gas generator protrudes only at one end of the tubular gas generator and the protruding strip lies on one side against the tubular gas generator. Also in this case the tubular gas generator is arranged inside or underneath the airbag.
The folding according to the invention is carried out in such a way that the airbag is placed in a first step in straight at least roughly parallel folds and that the airbag packet thus formed is then bent down additionally at least once from its middle area out towards the ends of the folds in a plane which runs parallel to the two planes in which the lower and upper fold edges each lie and parallel to the front side of the airbag module facing the occupant in the installed state. The airbag packet is then likewise folded concertina-like in this plane.
In a preferred use of the folding for a driver airbag module the airbag is folded on each side of a pot-shaped gas generator in a first step in straight parallel folds in the direction of the gas generator. In a second step the areas of the airbag protruding at the gas generator are compacted into a packet which is then folded up concertina-like against the gas generator.
In an embodiment for an airbag module where a tubular gas generator is mounted inside or underneath an airbag the airbag is folded at first at least approximately parallel to the longitudinal axis of the tubular gas generator. The ends of the folded airbag protruding over the ends of the tubular gas generator are bent down in opposite directions and placed against the middle sections or against the middle part of the airbag.
In a further embodiment with an airbag module where a tubular gas generator is mounted asymmetric inside or underneath t
Christie Parker & Hale LLP
English Peter C.
Petri AG
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