Land vehicles – Wheeled – Attachment
Reexamination Certificate
2001-12-10
2003-07-29
Johnson, Brian L. (Department: 3618)
Land vehicles
Wheeled
Attachment
Reexamination Certificate
active
06598902
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method utilizing welds, reinforced with sewn seams, to adhere two fabrics together to form an inflatable airbag cushion. Although welded seams provide better and more easily produced attachment points between multiple layers of fabrics, not to mention improved manners of reducing air or gas permeability at such attachment points, the utilization of sewn seams adjacent to such welded areas provides stronger reinforcement, and thus more reliable nonpermeable fabrics. Seam welding generally concerns the utilization of a film on the underside of a fabric which, upon contact with a second, film-treated fabric and upon exposure to high frequency energy, forms a bead of polymeric material at the attachment point between the two fabric layers. Lower numbers of sewn seams may be utilized to permit sufficient reinforcement if the size of the formed polymeric bead is of sufficient size to permit thorough sealing and adhesion between the fabric layers. Such a specific reinforced fabric, as well as high bead-size welded airbag fabrics are encompassed within this invention.
BACKGROUND OF THE PRIOR ART
All U.S. patents cited herein are hereby fully incorporated by reference.
Inflatable protective cushions used in passenger vehicles are a component of relatively complex passive restraint systems. The main elements of these systems are: an impact sensing system, an ignition system, a propellant material, an attachment device, a system enclosure, and an inflatable protective cushion. Upon sensing an impact, the propellant is ignited causing an explosive release of gases filling the cushion to a deployed state which can absorb the impact of the forward movement of a body and dissipate its energy by means of rapid venting of the gas. The entire sequence of events occurs within about 30 milliseconds. In the undeployed state, the cushion is stored in or near the steering column, the dashboard, in a door, or in the back of a front seat placing the cushion in close proximity to the person or object it is to protect.
Inflatable cushion systems commonly referred to as air bag systems have been used in the past to protect both the operator of the vehicle and passengers. Systems for the protection of the vehicle operator have typically been mounted in the steering column of the vehicle and have utilized cushion constructions directly deployable towards the driver. These driver-side cushions are typically of a relatively simple configuration in that they function over a fairly small well-defined area between the driver and the steering column. One such configuration is disclosed in U.S. Pat. No. 5,533,755 to Nelsen et al., the teachings of which are incorporated herein by reference.
Inflatable cushions for use in the protection of passengers against frontal or side impacts must generally have a more complex configuration since the position of a vehicle passenger may not be well defined and greater distance may exist between the passenger and the surface of the vehicle against which that passenger might be thrown in the event of a collision. Prior cushions for use in such environments are disclosed in U.S. Pat. No. 5,520,416 to Bishop; U.S. Pat. No. 5,454,594 to Krickl; U.S. Pat. No. 5,423,273 to Hawthorn et al.; U.S. Pat. No. 5,316,337 to Yamaji et al.; U.S. Pat. No. 5,310,216 to Wehner et al.; U.S. Pat. No. 5,090,729 to Watanabe; U.S. Pat. No. 5,087,071 to Wallner et al.; U.S. Pat. No. 4,944,529 to Backhaus; and U.S. Pat. No. 3,792,873 to Buchner et al.
The majority of commercially used restraint cushions are formed of woven fabric materials utilizing multifilament synthetic yams of materials such as polyester, nylon 6 or nylon 6,6 polymers. Representative fabrics for such use are disclosed in U.S. Pat. No. 4,921,735 to Bloch; U.S. Pat. No. 5,093,163 to Krummheuer et al.; U.S. Pat. No. 5,110,666 to Menzel et al.; U.S. Pat. No. 5,236,775 to Swoboda et al.; U.S. Pat. No. 5,277,230 to Sollars, Jr.; U.S. Pat. No. 5,356,680 to Krummheuer et al.; U.S. Pat. No. 5,477,890 to Krummheuer et al.; U.S. Pat. No. 5,508,073 to Krummheuer et al.; U.S. Pat. No. 5,503,197 to Bower; and U.S. Pat. No. 5,704,402 to Bowen et al.
As will be appreciated, the permeability of an airbag cushion structure is an important factor in determining the rate of inflation and subsequent rapid deflation following the impact event. Different airbag cushions are utilized for different purposes. For instance, some airbag cushions are installed within inflation modules for driver protection within the steering column of an automobile. Others are utilized as protection for front seat passengers and are installed in and around the glove compartment and/or on the dashboard in front of such a passenger seat. Still others have been developed in an effort to protect all passengers during a long-duration impact event, such as, for example, a rollover collision. In those types of crashes, the target airbag cushion must inflate quickly under high pressure (such as between about 40 and 50 psi) and remain inflated at relatively high pressures in order to provide the greatest degree of protection to such passengers. Furthermore, such long-duration airbag cushions preferably comprise “pillow” formations created through the attachment of at least two different fabrics or fabric ends together and sealed, sewn, or the like, together. Upon inflation the free space between the attachment points inflate as well, thereby producing the desired cushioned “pillow” structures. Such long-duration, “pillowed” structures have been disclosed in the prior art as airbag cushions within U.S. Pat. No. 5,788,270 to Haland. However, in order to provide a suitable, effective airbag fabric and cushion comprising two or more points of attachment between fabrics or fabric ends, there has been a need to improve upon the structural integrity of the seams at such attachment points to prevent unwanted and potentially harmful leakage of gas or air from within the target airbag cushion. The prior art has discussed the development of coatings to place over the sewn seams at such attachment points in order to seal the potentially loose portions of such seams and/or to keep the individual yams of the airbag fabrics at the attachment points stationary in order to prevent yam shifting and thus possible openings for air or gas leakage. However, such coatings have not proven fully capable of providing such needed benefits. Most coatings comprise silicones which actually tend to act as yam lubricants and thus not only do not prevent, but permit deleterious yarn shifting. Also, the amount and/or thickness required of such coatings is relatively high which creates a tackiness problem between fabrics portions during storage in an inflation module. When the airbag cushion is packed tightly in such closed quarters, the coatings may tend to increase the adhesiveness between the contacting fabric portions which may consequently create difficulties in unfolding of the cushion upon inflation. Furthermore, such thick coatings are rather costly and thus increase the overall price passed on to the consumer. In recent years, there has been a tremendous push to producing highly effective airbag cushions while simultaneously lowering the costs associated with such production. Thus, some manner of providing proper, well-performing, cost-effective attachment points between airbag fabrics or airbag fabric ends is necessary to meet these industry requirements. To date, the prior art has not accorded such an improvement in performance and cost to the airbag cushion market.
SUMMARY OF THE INVENTION
In view of the foregoing, it is a general object of the present invention to provide an effective, reinforced, welded airbag fabric for incorporation within an airbag cushion for utilization within a vehicle restraint system. The term “vehicle restraint system” is intended to mean both inflatable occupant restraining cushion and the mechanical and chemical components (such as the inflation means, ignition means, propellant, and the like). It is a more particular o
Johnson Brian L.
Klebe G B
Milliken & Company
Moyer Terry T.
Parks William S.
LandOfFree
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