Land vehicles – Wheeled – Attachment
Reexamination Certificate
1999-10-15
2001-04-10
Rice, Kenneth R. (Department: 3611)
Land vehicles
Wheeled
Attachment
C280S743100
Reexamination Certificate
active
06213500
ABSTRACT:
The present invention relates to an airbag for a vehicle safety restraint and particularly to a side impact airbag to protect a vehicle occupant from injury in the event of the vehicle sustaining a laterally inflicted impact, and to a method of folding a side impact airbag.
Side impact airbags are known and are for example described in applicant's own International application published under number WO 96/07563, the subject matter of which is incorporated by reference into the present application. A side impact airbag with two compartments to protect respectively the head and the thorax of an occupant, is also known from GB 2 229 061.
The object of the present invention is to provide an improved side impact protection device, in particular a side impact airbag and also to provide an improved method of folding the same.
A problem occurs in side impact airbags in that the occupant's door-side arm tends to interfere with and restrict the correct inflation of the airbag. This can result in injuries to the occupant's air and/or shoulder.
An object of one aspect of the present invention is to provide an improved side impact airbag which is shaped and mounted so as to inflate at such a speed and in such a direction as to reduce the risk of inflation induced injuries to the vehicle occupant.
According to a first aspect of the invention there is provided a side impact airbag comprising a first and a second inflatable compartment, the first compartment being adapted and mounted in a vehicle in a position from which it can inflate, on deployment in the event of a crash, to occupy an area generally adjacent to the thorax and the shoulder of a vehicle occupant, and the second inflatable compartment being adapted to inflate, on deployment, to occupy an area generally adjacent to the head of the vehicle occupant, wherein the first and the second compartments are separated one from the other by a dividing panel formed of airbag fabric and are pneumatically connected to each other by means of at least one vent hole formed in the panel, characterised in that fabric of a first weight is used for the lower compartment which protects the thorax and shoulder areas of the vehicle occupant, and the second, upper, compartment of the airbag, which protects the head of the occupant, is formed of fabric of a second, lower, weight.
Advantageously the lower compartment has a hole for receiving inflation gas from an inflation the event of airbag deployment, and the dividing panel is arranged so that it will be in a position approximately at the level of the occupant's shoulder when the airbag is fully inflated.
The lower compartment may thus be of increased size compared to known dual cavity airbags and this allows the airbag to inflate more quickly past the arm of an occupant and thus for the upper, second compartment to pass the shoulder and thus restrain the head earlier in a crash event. Traditional side impact airbags tend to have a problem of interference with a occupant's arm, whereas this invention reduces that problem.
According to one embodiment the airbag is formed of three pieces of fabric stitched together: a first piece forms one side wall of the airbag, a second piece forms a second side wall and a third piece forms the panel dividing the two compartments. Of course, additional material may be used for one/or more tethers, and or for reinforcing the gas inlet opening and/or for other strengthening.
Preferably the airbag is arranged and mounted so that as it inflates a rotational force is imparted to the upper, outer region of the airbag (relative to the vehicle occupant) to bias the airbag to move towards the occupant. This twisting motion may be imparted by mounting the airbag at an oblique angle to the horizontal, for example at an angle of between 10° and 40° to the horizontal.
Optionally the inflation profile of the airbag and the elongation of it towards the occupant during deployment is further controlled by retaining tethers within one or both inflatable compartments and/or by stitches either joining the side panels of the airbag together, or forming one or more tucks in one or both sides. The stitches may be tear stitches which burst at a predetermined pressure as the airbag inflates. The tethers may also have tucks in them by means of tear stitches.
The requirement for strength is not so important in the head bag as in the thorax bag, but is it preferable that the head bag deploys quickly to move past the arm and shoulder before movement of the occupant blocks its deployment path. The head bag is preferably formed of a low permeability and a low frictional fabric. For example fabric of 210 denier would be suitable for the upper head compartment and of 630 denier for the lower thorax compartment. The low denier fabric has the advantage, for the head compartment, of being of relatively low weight and will therefore move faster on deployment. The inflation characteristics of this airbag cushion gives the surprising result that there is less risk to the occupant who is out of position.
According to another embodiment this may advantageously be accomplished by forming the main side panels of the airbag together with the dividing panel from only two pieces of fabric. One piece, of a predetermined denier is folded in half and stitched at the sides and the top to form the upper head compartment. One or two vent holes are formed in the middle region and this forms the dividing panel. The second piece is folded and stitched at the sides, the open top being joined by stitching to the head section on either side of the vent hole or holes. The second piece of fabric can be of a different denier. For example 210 denier material may be used for the upper head section and heavier, less permeable 630 denier material for the lower thorax section. Of course the lower compartment may be formed first and stitched to the fabric for the upper compartment before the upper compartment is stitched.
Evidently further fabric pieces may be required for reinforcement, for example in the region of the inflation inlet, and for tethers and such like.
This arrangement requires less critical sewing lines than with the known arrangements, less pieces of fabric and is thus easier to sew, and produces overall a lighter airbag since a lighter fabric can easily be used for the upper section without prejudicing the performance of the lower compartment. The use of fabrics of different permeabilities also allows for tailoring the damping characteristics as appropriate to the body region to be protected. Previously this was only achievable by coating part of the bag which is expensive.
The airbag according to the first aspect of the invention may be mounted in a vehicle door, for example in the door trim or in the padded upholstery.
Alternatively the airbag may be mounted in the vehicle coat, either in the upholstery or in the structure of the seat itself.
According to a second aspect of the present invention there is provided a new method of folding a side impact airbag and particularly folding an airbag according to the first aspect. This folding method aims to overcome many of the disadvantages of the prior art folding methods by producing more consistent unfolding of a side impact airbag during deployment and more reliable positioning of the airbag and of the different compartments of the airbag in relation to the parts of the body of the vehicle occupant to be protected.
This new folding method comprises laying an uninflated airbag generally flat so that it presents a generally oblong shape in plan view with two opposing minor sides and two opposing major sides, the airbag having a gas inlet opening arranged at or in the region of a first minor side of the shape so formed, subsequently, folding or rolling the upper part of the airbag and folding the folded or rolled part to be on top of the lower part, and, as a first step: folding the two major sides inwardly towards a central major axis, preferably by folding the sides behind and underneath the body of the airbag; as a second step: rolling the
Bonsch Udo
Jost Markus
Jost Stefan
Kretschmar Albrecht
Priemer Peter
Breed Automotive Technology Inc.
Rice Kenneth R.
Seitzman Markell
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