Land vehicles – Wheeled – Attachment
Reexamination Certificate
1999-05-05
2001-06-26
Dickson, Paul N. (Department: 3618)
Land vehicles
Wheeled
Attachment
Reexamination Certificate
active
06250676
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a gas bag for an airbag module, as well as to a method and device for folding a gas bag.
The gas bag of an airbag module is folded in the rest position in the area of the gas generator and is covered from the passenger cell of the motor vehicle by means of a covering cap. The type of folding differs little irrespective of the position of the airbag, i.e. whether it is a driver, passenger or side airbag. Thus, in EP A 0 705 738 A1 a side airbag is described wherein the gas bag, as in the case of a driver airbag, is mounted at the side above the gas generator. A gas bag of a side airbag is also folded in a similar way, as is known from EP A 0 686 531 A. A gas bag folded in this way is extended during unfolding by the gas emerging from the gas generator. The outer folded edges are thereby moved to the side and forward until completely unfolded. Whereas with a driver airbag, as a rule, a free unfolding is guaranteed, in the case of a passenger and side airbag, unfolding can be impeded by external structural parts. These disadvantages particularly occur in the case of a side airbag which has to unfold substantially to the side and vertically and is thereby obstructed by parts of the door trim and by the seat. In the case of the side airbag there is the danger therefore that during unfolding it becomes hooked on obstructions and is deflected by these obstructions into an undesired direction. Apart from this faulty gas bag design and the faulty gas bag position, the unfolding time is also extended. The protection for the occupant is, therefore, incomplete and may even occur too late.
From specifications DE PS 195 16 494 C1, U.S. Pat. No. 5,496,061 and EP 0 523 704 A, it is known to fold the gas bag telescopically so that further telescopic folds extend around a telescopic fold stretching into the inside of the gas bag and run substantially across the unfolding direction.
SUMMARY OF THE INVENTION
The object of the invention is to fold the gas bag so that the risk of the gas bag being impeded by obstructions as it unfolds is at least considerably reduced.
A gas bag for an airbag module wherein the gas bag is folded telescopically in the rest position, in which further telescopic folds extend around a telescopic fold stretching into the inside of the gas bag and run substantially across the unfolding direction, has according to the invention, in addition to the telescopic folding, at least one section which is gathered and/or chaotically folded. With this type of folding the folds lie inside the gas bag and are protected from contacting obstructions located in the unfolding direction. The outermost fold is unfolded first. As unfolding continues, the remaining folds are released from outside inwards and are supported on any obstructions which may exist. The remaining fold parcel, which is to be unfolded, is moved in this way to the proposed position unimpeded.
In one embodiment it is proposed that the telescopic folds are enclosed at least in part by crumple folds.
Depending on the proposed unfolding direction and the existing obstructions it may be expedient that the telescopic folds have different depths and/or directions. The upper folded edges of the telescopic folds lie in one embodiment substantially in one plane. It can however be expedient if the upper folded edges of the telescopic folds lie in surfaces inclined towards each other or in one surface which is curved outwards or inwards in the direction of the folds. The sequence and speed at which the folded layers unfold can hereby be influenced.
The telescopic folds extend at least from one side of the gas bag into same.
When using a tubular gas bag such as is suitable for a side airbag the telescopic folds preferably extend around its longitudinal axis. The gas bag is with this type of folding severely shortened in length when in the folded state.
In a further embodiment of the invention it is proposed that an outflow opening is provided in at least one fold which can be closed.
Furthermore, at least one stitched or rip seam is provided for presetting the direction or defining individual gas bag areas inside one fold or between at least two folds.
With a method according to the invention for folding a gas bag it is proposed that the gas bag is placed telescopically in folds into the inner cavity of the gas bag step-wise, at least from one side, and that the gas bag is then compressed so that the remaining gas bag fabric which is not yet folded lies in folds about the telescopic folds.
In one embodiment of the method, the gas bag which is to be folded is biased with compressed air and then placed telescopically in folds, up to a predetermined depth, into the inner cavity of the gas bag. Subsequently or simultaneously the compressed air is let down. The first telescopic fold thereby formed is secured. The gas bag is then biased with compressed air again and is folded again telescopically into the inside of the gas bag in a ring round the first telescopic fold whereby the compressed air is let down simultaneously or subsequently. After securing the first and second telescopic fold the process described for the second telescopic fold is repeated until reaching the desired number of folds.
In a further development of the method, it is proposed that in successive steps of the telescopic folding, folds of different depth are provided and/or the telescopic folds are made in different directions.
With a tubular gas bag the telescopic folds are preferably made in the direction of the center line of the gas bag.
A device according to the invention for folding a gas bag is characterized in that a housing is provided wherein the gas bag can be fixed at one end of the housing inside, whereby a folding mandrel can be inserted from this end, while at the other end of the housing there is a packing ram, which can be moved into the housing, and a displaceable folding lance is mounted in the center of the ram whereby at least one folding element fixed on the packing ram extends round the lance and wherein the folding mandrel has a recess into which the folding lance can be inserted.
The cross section of the housing corresponds substantially to the cross section of the airbag module with folded airbag.
Furthermore it is expedient to provide at the edge of the packing ram a stripper element which adjoins the inner wall of the housing and ensures easy movement of the packing ram in the housing.
REFERENCES:
patent: 4178017 (1979-12-01), Ishi et al.
patent: 4235453 (1980-11-01), Lawson et al.
patent: 5178407 (1993-01-01), Kelly
patent: 5275435 (1994-01-01), Fisher
patent: 5300011 (1994-04-01), Budde et al.
patent: 5360387 (1994-11-01), Baker
patent: 5391137 (1995-02-01), DePoy et al.
patent: 5456651 (1995-10-01), Baker et al.
patent: 5496061 (1996-03-01), Brown
patent: 5531476 (1996-07-01), Kerner
patent: 5613707 (1997-03-01), Berti
patent: 42 27 559 A1 (1994-02-01), None
patent: 44 40 844 A1 (1996-05-01), None
patent: 195 05 507 A1 (1996-08-01), None
patent: 195 16 494 C1 (1996-10-01), None
patent: 296 09 703 U1 (1996-11-01), None
patent: 0 443 485 A1 (1991-08-01), None
patent: 0 523 704 A1 (1993-01-01), None
patent: 0 686 531 A1 (1995-12-01), None
patent: 0 705 738 A1 (1996-04-01), None
patent: 0 734 911 A1 (1996-10-01), None
patent: 2 279 046 (1994-12-01), None
Disclosed Anonymously, “Side Impact Air Bag and method for Folding”, pp. 329/330, Research Disclosure, May 1996.
Adomeit Heinz-Dieter
Malczyk Axel
Markfort Dieter
Sturm Andreas
Werstat Wolfram
Dickson Paul N.
Foley & Lardner
Petri AG
Winner Tony
LandOfFree
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