Land vehicles – Wheeled – Attachment
Reexamination Certificate
1999-04-23
2002-12-17
Rice, Kenneth R. (Department: 3627)
Land vehicles
Wheeled
Attachment
C280S731000
Reexamination Certificate
active
06494484
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to inflatable cushions used in vehicle occupant restraint systems. More particularly, this invention relates to a cushion constructed from fabric in the form of two congruent equiangular polygons that may or may not share a common side and that, during the construction process, are superimposed in congruent fashion and joined along their respective coincident edge portions to form a polygon-shaped cushion.
BACKGROUND OF THE INVENTION
An inflatable restraint cushion, or air bag, plays an important role in protecting the occupants of a vehicle from injury due to collision against the car body. Typically, the air bag is disposed within a supporting structure such as a dash panel, steering wheel, door panel, or other fixed portion of a car body in opposed or adjacent relationship to a seat in the vehicle. When inflated rapidly by the pressure of a reaction gas released from an inflator during a collision, the air bag serves as a protective barrier between the vehicle occupant and the steering wheel or other portion of the vehicle body against which the occupant might otherwise be thrown.
Air bags have been used in the past to protect both the vehicle operator and vehicle passengers. Systems for the protection of the vehicle operator are typically mounted in the steering column of the vehicle and utilize cushion constructions that deploy directly towards the driver. These driver-side air bags can be of a relatively simple configuration in that they function over a small, well-defined area between the driver and the steering column. Typically, driver-side air bags are circular or substantially circular in shape when viewed from the front or the back. Such circular air bags are frequently constructed by superimposing, aligning, and joining, along their respective coinciding edges, two generally circular fabric sections that are separately cut from a web or blank of air bag fabric. While such circular air bags are functionally effective, the circular shape of the front and back fabric sections or panels from which the air bags are constructed does not lend itself to the efficient utilization of fabric during the manufacturing process. Specifically, the arrangement of these circular pieces or panels on a given blank of air bag fabric does not result in efficient fabric utilization or yield. Fabric is wasted in producing such circular cushions since the circular templates do not have straight edges which can be aligned with the edges of the fabric blank or which can be juxtaposed in close proximity on the fabric to provide common or nearly common adjacent edges with minimal fabric waste between neighboring cut sections. Furthermore, because use of circular or other curved panels frequently results in oddly-shaped sections of fabric between neighboring cut panels, utilizing such inter-panel fabric to make other necessary parts of the air bag (e.g., various reinforcements, etc.) is often difficult.
As used herein, it is intended that the following terms be defined as indicated: The term “polygon” is a plane geometric figure having n sides and n vertices. An equiangular polygon is a polygon in which all the angles comprising the vertices are equal. A regular polygon is an equiangular polygon in which all sides are of equal length. A convex polygon is one for which no side, if extended, will enter the polygon. Unless otherwise specified, the term “polygon” shall refer to a convex, equiangular polygon. The term “congruent” shall be used to mean capable of being superimposed so as to have a perimeter that is coincident throughout. The term “fabric” shall be used in a broad sense to describe any woven or non-woven fabric, film, polymer, combinations or composites thereof, or other suitable material from which the individual panels comprising an air bag may be constructed.
It is common, particularly in air bags designed for the protection of vehicle drivers, to find such air bags fabricated from the seaming or joining of two similarly-dimensioned circular panels along their respective perimeter edges after such circular panels have been cut from a blank of suitable air bag fabric and superimposed in congruent fashion. The instant invention provides for the use of relatively simple polygonal starting geometries for the fabric panels in order to reduce air bag fabric waste by reducing the quantity of fabric between the panels on a fabric blank. Additionally, fabric waste may be reduced because, when such polygons are used, the inter-panel fabric (which might otherwise have to be discarded when circular panels are used) tends to have a straight-sided shape from which the fabrication of other components needed for air bag construction (e.g., reinforcements and the like) may be more easily constructed, thereby saving on the area of uncut fabric blank that must be used in the construction process.
It has been found that fabric utilization can be significantly improved by substituting polygon shapes, and particularly equiangular polygons having n sides, where n is at least five, for the circular-shaped panels of the prior art. In one preferred embodiment, two such panels are individually cut and the cushion is constructed by superimposing the panels in congruent fashion (i.e., with coincident edges) and joining each of the n sides of one of the polygon-shaped panels to the respective coincident n
th
side of the other panel. In another preferred embodiment, a single panel is cut in the form of a pair of abutting, congruent n-sided equiangular polygons that share a common uncut side, i.e., a single, dual-lobed panel, having a perimeter comprised of 2n−2 sides, in which each lobe resembles an n-sided polygon having n−1 cut edges. This single piece panel may be folded about an axis that coincides with the shared uncut side to allow the lobes to be superimposed in congruent fashion. By joining the respective n−1 coincident cut edges, a polygonal cushion similar to the two-panel cushion of the first embodiment may be formed, but without the need for a joining operation along the shared side due to the lack of any cut edge.
The polygon shapes can be placed in close proximity to one another on the fabric blank from which they are cut, thus minimizing fabric waste and cost, and providing a useful advancement over the present art. The fabric between polygon-shaped panels (the inter-panel fabric) tends to have straight sides and is therefore easier to utilize in the manufacture of other air bag components (e.g., reinforcements or other components). The advantages of the present invention include better fabric utilization and an overall simplification of the manufacturing process. By providing congruent polygonal fabric panels having linear edge segments, this invention facilitates seaming operations by improving in the ease, effectiveness, and efficiency with which the cut pieces can be aligned and joined during the seam formation process. Prior designs tend either to result in relatively poor material utilization due to the use of unusual panel shapes or to require more complex aligning, folding or sewing operations during the seaming process than is found in the instant invention. Accordingly, cost is lowered due to the improved yield per fabric blank as well as the increased efficiency with which the cutting and joining operations can be performed.
All of these advantages apply to the embodiment using two separate n-sided congruent polygon panels as well to the embodiment using a single, dual-lobed panel, with congruent lobes in the shape of the same n-sided polygon. However, an additional advantage of the latter embodiment of this invention is the additional simplification in cutting and sewing operations this embodiment provides. Because of the common uncut boundary shared by the n-sided polygons comprising the lobes, the number of coincident perimeter panel edges requiring joining (after the panel is folded and the lobes are superimposed in congruent fashion) generally is equal to n−1. Sewing along the entire length of
Bosgieter Lance M.
Keshavaraj Ramesh
Fisher George M.
Jasmin Lynda
Milliken & Company
Moyer Terry T.
Rice Kenneth R.
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