Package making – Methods – With contents treating
Reexamination Certificate
1999-06-22
2001-07-17
Gerrity, Stephen F. (Department: 3721)
Package making
Methods
With contents treating
C053S116000, C280S743100, C493S450000
Reexamination Certificate
active
06260330
ABSTRACT:
TECHNICAL FIELD
The invention relates to a method and to an apparatus for the folding of an inflatable airbag for motor vehicles.
BACKGROUND OF THE INVENTION
Methods and apparatuses of this kind serve to fold together an inflatable airbag to a size which permits the folded airbag to be mounted in a vehicle as a part of an airbag module for example as a driver's, a passenger's or a side airbag. It is known that the airbag should be folded in such a manner that it can unfold as quickly as possible in the event of a collision.
In the prior art, numerous machines have been provided for folding such air bags in fan style folds using paddles to create the folds of the airbag.
SUMMARY OF THE INVENTION
One object of the invention is to provide a method and an apparatus for the folding of an inflatable airbag by means of which an airbag can be folded rapidly and economically and nevertheless in such a manner that it can unfold readily in the event of a collision.
These advantages take place through the features of the invention which relate to the folding method, and in particular in that the method comprises the steps that an airbag to be folded is fixed in a housing with its closed end at an upper part of the housing and is fastened with its open end at a base element lying opposite to the upper part in such a manner that the base element seals off the interior of the airbag against the inner space of the housing; that the housing and the base element are moved relative to one another; and that the pressure within the airbag and/or the housing is varied during the relative movement.
The invention makes available a particularly simple folding method in which substantially only a housing and a base element which is relatively movable with respect to it are required. Moreover, the method can be carried out largely automatically. A further advantage of the invention consists in that the folding of the airbag takes place practically without contact so that the danger of damage to the airbag is small.
In accordance with a preferred embodiment of the invention the pressure is varied only within the airbag and in such a manner that the pressure is alternatingly higher and lower than an average value P
0
, which preferably corresponds to the ambient pressure. Through this it is achieved that the not yet folded region of the airbag is alternatingly pressed outwardly in the direction of the inner wall of the housing and is drawn or sucked respectively away from the inner wall of the housing in the direction towards a centre axis of the housing. In this way the airbag is laid in folds in meander shape in the region between the centre axis of the housing and its inner wall.
In accordance with another embodiment of the invention the pressure within the airbag and the housing is varied in such a manner that it is always higher in the airbag and always lower in the housing than an average value P′
0
, which preferably corresponds to the ambient pressure, or in such a manner that it is alternatingly higher and lower in the airbag than in the housing, but however is higher both in the housing and in the airbag than a value which preferably corresponds to the ambient pressure.
In the first alternative of this embodiment both pressures act fundamentally in the same direction in such a manner that the airbag is both pressed against the inner wall of the housing and is also sucked from the direction of the inner wall of the housing. In addition the pressures are varied in a definite way, which is dependent on the concrete design of the base element and of the housing, in such a manner that the airbag can be folded in the desired manner.
In the second alternative of this embodiment the two pressures work counter to one another, with the airbag being either pressed in the direction of the inner wall of the housing or away from the latter depending on which pressure is the higher at the moment.
In accordance with a further preferred exemplary embodiment of the invention an inhomogeneous pressure distribution is produced within the airbag and/or the housing. Through this the not yet folded region of the airbag can be brought into any desired shape at any time point during the relative movement of the housing and the base element.
The folding method in accordance with the invention thus enables a given fold structure to be intentionally produced, with the airbag preferably being laid together in the manner of a sleeping bag.
The object of the invention also takes place through the features relating to the folding apparatus, and in particular in that a housing and a base element are provided, with it being possible to fix an airbag to be folded in the housing with its closed end at an upper part of the housing lying opposite to the base element and to fasten it with its open end at the base element in such a manner that the base element seals off the interior of the airbag against the inner space of the housing, with the housing and the base element being movable relative to one another and the base element being provided with at least one control opening via which the pressure within the airbag to be folded can be varied.
Through the invention a particularly simply constructed folding apparatus is provided which enables a largely automatic and non contact folding of an airbag.
In accordance with a preferred embodiment of the invention the space bounded in a final position by the housing and the base element corresponds at least approximately to the space which is available in an airbag module housing for the folded airbag, which preferably has the final packing size. Through this the airbag which is folded with the apparatus in accordance with the invention can be integrated into an airbag module immediately after the completion of the folding process, through which the time required for the manufacture of the airbag module is shortened.
In accordance with a further preferred exemplary embodiment of the invention the edge which faces the base element of an upper part of the housing, which is formed as a cap, is formed as an abutment surface which cooperates in a final position with the base element or with an airbag module which is arranged on the base element, with it preferably being possible to fasten the airbag to be folded at the base element in the state connected to a holder element and/or a base plate of an airbag module. Thus in this embodiment an airbag module housing is simulated by the upper part of the housing, which is formed as a cap. In the final position the abutment surface of the cap comes to lie against an airbag module, in particular a holder element at a base plate, which is arranged on the base element. Thus after the removal of the airbag module having the folded airbag from the housing of the folding apparatus, only the airbag module housing need still be placed on.
If in accordance with a further preferred exemplary embodiment the cap which forms the upper part of the housing is made releasable from the housing wall, the connection between the housing wall and the cap can be released after the folding process and the complete airbag module, which is ready for installation, and of which the housing is formed by the cap, can subsequently be taken out. Then only a connection between the cap and the holder element or the base plate of the airbag module respectively need still be produced. For the next folding process then a new cap is connected as an upper part to the remaining housing wall.
In accordance with a further exemplary embodiment of the invention the housing is surrounded by a hood, with an intermediate space being formed, and is provided with at least one control opening to the intermediate space via which the pressure in the inner space of the housing can be varied. This embodiment enables the airbag to be folded to be acted on additionally from the outside in that a pressure and/or vacuum source is connected to the space formed between the housing and the hood by the intermediate space. The possibilities of producing different fold structures are hereby exte
Borowski Joachim
Varcus Johannes-Alexander
Delphi Technologies Inc.
Gerrity Stephen F.
Marra Kathryn A.
LandOfFree
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