Manufacturing container or tube from paper; or other manufacturi – Bending – Folding
Reexamination Certificate
1998-03-11
2001-01-09
Vo, Peter (Department: 3721)
Manufacturing container or tube from paper; or other manufacturi
Bending
Folding
C493S243000, C493S451000, C493S458000, C493S940000, C280S728100, C280S743100
Reexamination Certificate
active
06171228
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to airbags, and more particularly to a method and apparatus for folding an airbag.
From German Patent No. DE 44 22 276 A1 an airbag is known for an airbag module where the collapsed airbag has main folds which run at least in part along closed paths around an imaginary center on the substantially empty spread-out airbag. The closed main folds preferably describe circular paths or ellipses of slight eccentricity. Secondary folds are also provided which arise naturally during collapsing of the airbag.
This path of the main folds has the advantage that the folded airbag can open very quickly and easily. Particularly during the unfolding of such an airbag there is not the danger that the inner pressure produced in partial areas of the airbag will impede the opening of further folds. This airbag can thereby be used for driver, passenger and side airbags. The drawback with this folding is that the expense for folding is considerable particularly if the folding is carried out mechanically.
Furthermore from U.S. Pat. No. 4,173,356 an airbag is known which is folded concertina-like in the direction of the blow-in mouth. The main folds thereby run along parallel straight lines. An airbag thus folded can unfold quickly and simply wherein it is only suitable for passenger or side airbags in this type of folding owing to its elongated shape which is essential for a sufficient volume. It could only be used as a driver airbag if the ends are turned in. There is then however the danger that the inner pressure impedes the opening of some folds.
From U.S. Pat. No. 3,876,272 an airbag is known which has several inner and outer main folds relative to a longitudinal axis. An airbag folded in this way can also unfold rapidly and quickly.
The objective of the invention is therefore to reduce the expense for folding in the case of a universal airbag which is folded so that the inner pressure does not impede the opening of the folds.
SUMMARY OF THE INVENTION
With a method for folding an airbag which has in the folded state at least one inner and one outer main fold wherein the latter runs at a greater distance from the longitudinal axis than the inner main fold, according to the invention the clamped airbag is pre-shaped so that it extends in the direction of a longitudinal axis on the sleeve face of the inner main fold or main folds provided. The airbag is then fixed in the area of the inner main fold or inner main folds provided and is pressed or drawn outwards in the area of the outer main fold or main folds provided. The airbag is then compressed in the direction of its clamping point.
With this method first the position of the sleeve face of the inner main fold or main folds is fixed. The outer folds are then formed by sliding or drawing to the outside the parts of the airbag not fixed there. The advantage is that the folding process can be readily mechanized and automated whereby the technical expense is reduced compared to known folding. Rapid folding is possible. This type of folding allows also a favorable storage of the gas generator which can also be inserted afterwards.
An alternative to the aforesaid method exists where the clamped airbag is pre-formed so that it extends in the direction of a longitudinal axis on the sleeve face of the outer main fold or main folds provided, that the airbag is then fixed in the area of the outer main fold or folds provided and pressed or drawn inwards in the area of the inner main fold or main folds and that the airbag is then compressed in the direction of its clamping point.
With this method thus first the position of the sleeve face of the outer main fold or main folds is fixed. The inner main fold or inner main folds are then formed by sliding or drawing inwards the parts of the airbag not fixed there.
In order to carry out the folding method the airbag is preferably clamped in the area of its blow-in mouth or inflation opening wherein the longitudinal axis about which the folding is carried out then runs approximately perpendicularly through the blow-in mouth.
The shaping and temporary fixing of the airbag in the area of the outer main fold or main folds provided is preferably carried out by means of compressed air and the shaping and fixing of the airbag in the area of the proposed inner main fold or main folds is preferably carried out by means of mechanical aids.
In a preferred embodiment the method is designed so that the airbag prefitted on a generator support plate is tensioned over one or more hollow cylinders until it adjoins same and is completely stretched. Folding elements are then fitted on the airbag in the area of the inner main fold or main folds provided. These folding elements fix the airbag at the points where the inner main fold or the inner main folds are provided. The hollow cylinder is then biased with compressed air wherein the airbag is pressed outwards at the non-fixed points. The outer main folds are then formed in these sections which have been pressed to the outside. These steps mentioned up until now substantially determine the sleeve faces in which lie the inner and outer main folds.
At the end of these aforementioned steps the hollow cylinder is then pushed with the folding elements in the direction of the generator support plate whereby the compressed air can escape. In this method step the final folding of the airbag takes place. At the end of the folding process the folding elements and the hollow cylinder are removed and then a cover cap and generator are fitted.
A device for carrying out the method is characterized in that a shaping body is provided for pre-forming the airbag and that displaceable folding elements are provided in a ring around these shaping bodies at a distance from the inner main fold or main folds provided across the longitudinal axis of the shaping body.
In a preferred embodiment a hollow body is provided which has through openings on its sleeve face and can be attached to a compressed air source. Compressed air is blown in through the openings into the airbag and this is then inflated in the areas of the outer main fold or main folds provided.
In a preferred embodiment a hollow cylinder is provided as a hollow body.
A further embodiment proposes that the shaping body is mounted in an underpressure or vacuum chamber. In this case the areas of the airbag in which the outer main fold or main folds are provided are then drawn outwards.
In a further embodiment a shaping body is provided which has on its sleeve face or outer surface grooves for blowing in compressed air or sucking out air. In this embodiment the shaping body need not be a hollow body for supplying compressed air into the airbag.
Folding plates are preferably provided as folding elements and have a forked section which matches the path of the sleeve face of the hollow body.
If several inner and outer main folds are provided the parts of the fork lie in one plane.
If only one inner and one outer main fold are provided the forked section of the folding plate has mutually restricted parts. These restricted parts form with an off-set arrangement of the folding plates a spiral shaped line which corresponds to the inner main folding line .
Cables or tongs can also be used as folding elements.
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Marotzke Thomas
Pausch Tobias
Christie Parker & Hale LLP
Harmon C.
Petri AG
Vo Peter
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