Package making – With contents treating – Reshaping
Reexamination Certificate
1998-12-29
2001-10-23
Tolan, Ed (Department: 3725)
Package making
With contents treating
Reshaping
C053S117000, C053S429000, C053S438000, C493S250000, C493S406000, C493S449000, C280S728100
Reexamination Certificate
active
06305150
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to airbag folding as well as to a method and device for folding airbags.
BACKGROUND OF THE INVENTION
In order to be able to stow the airbag of an airbag module in a steering wheel, or in the case of a passenger airbag module or side airbag module in the area of the dashboard or door, it is necessary to fold the airbag and press it into a container which is then closed. As well as other types of folding, there is one way of folding an airbag known from DE 44 22 276 A1 where the airbag has main folding lines which run at least in part along closed paths round an imaginary centre on the substantially empty spread out airbag. Folding the airbag down to the required packing density which is necessary for stowing the airbag in the steering wheel or on the dashboard is carried out so that in a first step folding is carried out along the said main folding lines and then this pre-folded airbag is folded or pressed, i.e. gathered up to the desired end shape through secondary fold lines which cross at least in part the main fold lines.
A device for producing this folding and gathering according to the said process preferably has a pot-like cylindrical part which can be inserted into the inflation opening of an airbag wherein the axial length of the cylindrical part corresponds at least approximately to the height of the airbag packet which is folded according to the first step. Furthermore a holding down member is provided which presses and holds the area of the airbag opposite the inflation opening on the bottom of the cylindrical socket part. Furthermore dish-like elements movable axially in the direction of the airbag are provided on opposite sides of the airbag and are arranged concentric with each other with different radii, with the radii of the opposing elements each being different.
Furthermore radial gathering elements are provided which can be brought together with the folded airbag into a packing device. A generator support can likewise be provided in this with the gas generator mounted in the support. The packing device furthermore has a device for pressing the folded airbag into the generator support.
If these folding, gathering and compacting elements are allotted known drives, e.g. pressure cylinders, then the cost of the drive is considerable.
SUMMARY OF THE INVENTION
The object of the invention is to provide a process and a device for rationally folding, gathering and compacting an airbag.
The airbag folding for an airbag used in an airbag module is characterized according to the invention in that the airbag is folded ring-shaped in the direction of an imaginary longitudinal axis wherein it has separate folds on the inside and on the outside of the ring. The imaginary longitudinal axis thereby preferably runs through the filling mouth of the airbag.
As opposed to the foldings known up until now, where the folds only run on the outer circumference of the folded airbag, the folding according to the invention represents a double folding where the airbag is folded again in addition directly adjoining the gas generator. This folding has the advantage that folding is produced free of rear cut sections which is important for the unfolding of the airbag and that only few method steps are required which can be carried out with a device which has few parts.
A further advantage is that the folding has an unfolding characteristic which is advantageous for the vehicle occupant. Thus during unfolding first only the inner or outer folds are stretched so that the airbag does not suddenly open fully in the direction of the occupant but full opening occurs with a slight time delay. This is designed so that on the one hand the occupant is not injured by the opening of the airbag whilst on the other hand the airbag does indeed open in good time to protect the occupant in the event of a crash.
A method for folding the airbag is designed according to the invention so that the empty airbag is stretched in the direction of a longitudinal axis running through the filling mouth and is gathered together within a boundary, preferably in a space with a ring-shaped cross-section in the direction of the longitudinal axis. Through stretching, the airbag is preshaped so that it obtains in rough strokes the circumference which it must have in the folded state in order to be stowed in a housing. Through the subsequent gathering which can take place for example through pressure action, the airbag then receives the height dimension which is required for stowing away the folded airbag. A rear-cut free folding is reached with this method without additional folding elements whereby this folding is called chaotic folding, i.e. the folds form naturally.
In one embodiment it is proposed that the spread out airbag is held in the area of its filling mouth and is drawn into a sleeve-shaped shaping body whilst at the same time an inner ram is introduced into the airbag and then the airbag is compressed in the sleeve-like shaping body by means of an outer ram. With this method the first significant step is a pulling process and the second significant step is a pressing process.
In another embodiment it is proposed that the spread out airbag is pressed through a ram into a sleeve-like shaping body and then is pressed in the direction of one end of the sleeve. Thus in this embodiment two pressing processes are carried out. As opposed to the embodiment described above here the spread out airbag in this embodiment requires no holder.
With first-mentioned embodiment of the process the spread out airbag is preferably both drawn into the shaping body and compressed from bottom to top. The airbag without a prefitted gas generator is thereby held in the spread out empty state at the filling mouth. When the gas generator is already fitted, the airbag is set in the spread out empty state on the gas generator.
In a further embodiment of the process it is proposed that the spread out airbag is held in its filling mouth area on an inner ram, that a sleeve-like shaping body is inverted over the airbag hanging down at the side of the ram and that then the airbag is compressed by means of an outer ram in the sleeve-like shaping body.
A device for folding an airbag is characterized in that a shaping body is provided, together with at least one device which stretches the airbag in a longitudinal axis running through the filling mouth and can introduce the airbag into the shaping body, as well as at least one device for compressing the airbag in the shaping body. In a preferred embodiment the shaping body is associated with a displaceable ram with smaller cross-section than the internal cross-section of the shaping body.
A sleeve is preferably provided as the shaping body. However a shaping body which is open on one or two sides can also be used.
A hollow cavity is provided between the displaceable ram and the shaping body and when using a sleeve as the shaping body the hollow cavity has a ring-shaped cross-section in which the airbag to be folded is introduced and compressed.
In a first embodiment a socket for the airbag is provided above the vertically mounted sleeve and can be inserted therein. Underneath the sleeve are two coaxial rams which can be inserted therein. The inner of the coaxial rams thereby represents the core for obtaining a ring-shaped hollow cavity whilst the outer ram is provided as a tool for compressing the airbag.
It is expedient if the inner contour of the shaping body corresponds to the outer contour of the folded airbag, that an inner ram is provided with an outer contour which matches the outer contour of a gas generator to be connected with the airbag, and that an outer ram is provided with an outer contour which corresponds to the inner contour of the shaping body.
The socket for the airbag or for the gas generator fixed on the airbag can be clamping tongs or a rod with foldable arm extensions.
In a further embodiment it is proposed that the shaping body formed as a sleeve is associated on one opening side with two rams which can be inserted coaxially into the sl
Foley & Lardner
Petri AG
Tolan Ed
LandOfFree
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