Land vehicles – Wheeled – Attachment
Reexamination Certificate
1997-11-25
2001-05-08
Swann, J. J. (Department: 3611)
Land vehicles
Wheeled
Attachment
C280S730100, C280S732000
Reexamination Certificate
active
06227568
ABSTRACT:
BACKGROUND
The invention relates to an airbag module.
The airbags used in known airbag modules have in the non-inflated state a circular, round, elliptical or similar shape. Passenger airbags use airbags which are generally three-dimensional structures comprised of several parts joined together. They are arranged so that in the fully inflated state they fill out the space between the dashboard and the occupant. During inflation, more particularly before reaching the final shape, these airbags have a substantially spherical shape. These known airbags expand in the event of a crash extensively both in the direction of the occupant and upwards so that a sufficiently large protective cushion is provided for the occupant.
The known airbags have, however, the disadvantage that they have, as a result of the even expansion in the inflated state, areas which are not necessary for the protection of the driver but which have to be inflated as well as those areas necessarily inflated for the protection of the driver in order to ensure the protective function of the airbag as a whole.
Furthermore there is the disadvantage that the airbag, more particularly in the case of an module for the passenger, cannot be effectively inflated and unfolded without additional measures. Moreover the windscreen has to undertake important support and directing functions during inflation of the airbag. The windscreen cannot however fulfil these functions if it is destroyed, for example in the case of a secondary impact.
In order to overcome this disadvantage, it is already known to arrange arrester straps in the airbag which define the expansion of the airbag in the direction of the windscreen. Arrester straps are however additional parts which increases the costs of the airbag.
From JP-A- 092746 (Patent Abstract) an airbag is known for a passenger seat which has a cross-section which is restricted in the middle. Airbag material is thereby saved. The drawback with this airbag is that it is supported on the front windscreen of the motor vehicle. This supporting function can however no longer be fulfilled if the windscreen is destroyed. A further disadvantage is that the restricted cross-section is located at a point where the force introduction through the moving occupant at impact is greatest, therefore this airbag provides only a restricted restraint action.
Furthermore from EP A 0 590 845 a side airbag is known which has a restriction in the area of the inflation mouth of the airbag. It is thereby divided into a lower and an upper area which are adapted in size to the provisions of the door. The restriction serves to supply the gas to the lower and upper areas and has no protective function. Since the lower and upper areas are inflated suddenly from area of the restriction, the seams and fabric are heavily stressed.
SUMMARY
According to an embodiment of the invention, it is possible to design and arrange an airbag so that large supporting faces are only provided where they are required for the occupant to impact and so that the airbag can unfold in a predetermined direction.
According to one embodiment of the invention, an airbag module for use in a motor vehicle is provided which includes a gas generator, and an airbag operatively connected to the gas generator, which has, in an inflated state, a restricted cross-section with substantially parallel sides and two opposite ends, and two enlarged sections, each adjoining a different one of the two opposite ends of the restricted cross-section such that the airbag is bone-shaped. One of the enlarged sections of the airbag is adapted to face an occupant of the motor vehicle.
Preferably, the airbag is mounted either underneath, above, or in the middle of the dashboard of the motor vehicle. The airbag may be installed in the driver's side of the motor vehicle.
According to another embodiment of the invention, an airbag module with airbag and gas generator, more particularly passenger airbag is provided, wherein the airbag has in the expanded position a restricted cross-section that it has at least approximately parallel sides adjoined on each side by enlarged sections so that the airbag is bone-shaped in the deflated state and in the inflated state. One of the enlarged sections of the airbag faces the occupant.
An airbag of this kind has the advantage that it accurately inflates in a certain direction without an arrangement of arrester straps since it can expand less in the areas with reduced cross-section than in the remaining areas. These restricted cross-sections serve in particular to receive the gas supply and are located in the areas of the airbag which are of secondary importance for the protection function. Through the omission of airbag sections which are not required for the protective function, it is possible to make the volume of the airbag smaller overall.
On the other hand, the airbag has a large volume in the front part facing the occupant which is of great importance for the protective function of the airbag. Furthermore due to this shape, the airbag inflates mainly in the direction of the occupant.
In one embodiment, the at least approximately parallel sides extend over approximately a third of the airbag length and the enlarged sections adjoining each side each extend likewise over about a third of the length. Furthermore it is expedient if an enlarged section of the airbag facing the occupant is larger than the other enlarged section.
In that the airbag has in the inflated state, in plan view, the shape of a bone, a central narrow section and two large-surface end sections are formed. In side view of this embodiment, facing the enlarged ends, a lens, or convex, shape is provided in the inflated state. This shape of the inflated airbag has in addition to the advantages already mentioned the further advantage that an improved support of the occupant's thorax is provided. This lens shape, i.e., the lower expansion of the airbag vertically, is thereby solely reached as a result of the cross-sectional shape of the airbag in the deflated state. Thus, neither an expensive sectional shape nor additional rip seams or arrester straps are required. This, airbag also expands more extensively horizontally than vertically without the need for rip seams.
An additional advantage exists in that the restriction reduces the airbag volume required. Thus a faster filling is possible and a smaller gas generator can be used, i.e., a gas generator with lower mass and smaller structural space.
The airbag preferably consists of two joined together parts having the same shape.
The gas generator should, when using the airbag according to an embodiment of the invention, be mounted below, above, or in the middle of the dashboard so that its main inflation direction runs substantially horizontally in the direction of the occupant.
The gas generator according to an embodiment of the invention is, in the case of a passenger airbag module, advantageously mounted underneath the dashboard so that its main inflation direction runs substantially horizontally in the direction of the occupant. This is furthermore assisted by the use of gathering folds in the airbag and an inflation diffusor. Through this arrangement of an airbag according to an embodiment of the invention, the advantages mentioned above are further intensified. Furthermore, the support of the airbag during inflation and in the inflated state is no longer provided by the windscreen, but rather, the dash board. A large support face is provided by the dashboard and the supporting forces are directed over a large surface into the dashboard. The airbag is thereby safer and can be better positioned and is also to be pressed up with more difficulty by the occupant, that is, it its more difficult for the occupant to bring the inflated airbag out of its natural position, which offers the occupant optimum protection. This better effectiveness of the airbag likewise allows a smaller airbag volume.
The advantages of the bone-shape airbag are also effective with a top and mid mounted installation position.
REFERENCE
Adomeit Heinz-Dieter
Braun Eleonore
Marotzke Thomas
Christie Parker & Hale LLP
Dunn David R.
Petri AG
Swann J. J.
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