Air bag fabric possessing improved packed volume and stable air permeability

Abstract

A fabric for use in an air bag is provided. The fabric of the invention is produced by mechanically compressing a preliminary fabric constructed substantially of synthetic yarn such that the packed volume per unit area of the compressed fabric is less than the packed volume per unit area of the preliminary fabric. Air permeability is not adversely affected.

Description

RELATED APPLICATIONS[0001]This application is a continuation-in-part of our pending prior application Ser. No. 08 / 842,825, pending, filed on Apr. 17, 1997, for AIR BAG FABRIC POSSESSING IMPROVED PACKED VOLUME CHARACTERISTICS the contents of which are incorporated herein by reference.FIELD OF THE INVENTION[0002]The invention relates generally to synthetic filament yarn fabric for use in the manufacture of an air bag and more particularly to fabric structures which can be packed into small volumes without unduly affecting air permeability.BACKGROUND[0003]Fabrics used for manufacturing air bags are required in general to process a limited and controlled air permeability. As will be appreciated, such fabrics are generally woven structures formed from synthetic yarns made up of a plurality of individual filaments. Formation of such fabrics may be carried out on weaving machines using air-jet, water-jet or mechanical means for insertion of filling yarns between a plurality of warp yarns i...

AI Technical Summary

Benefits of technology

[0009]In recognition of the foregoing and other limitations in the prior art constructions, it is a general object of the present invention to provide an air bag fabric of improved foldability which may be constructed from a broad range of yarn types.

[0010]It is a further object of the present invention to provide an air bag fabric of improved foldability wherein such improved foldability is achieved by means of inexpensive mechanical treatment processes without substantially increasing air permeability characteristics of the fabric.

[0011]It is yet a further object of the present invention to provide an air bag fabric of improved foldability wherein such improved foldability is achieved by means of mechanical treatment processes which additionally reduce variations in physical properties across the width of the fabric as may be introduced during weaving.

[0012]It is a further object of the present invention to provide a woven air bag fabric which does not exhibit substantial increases in permeability when subjected to biaxial forces in the warp and fill directions.

[0013]Surprisingly, it has been found that the above objects of improved foldability as measured by packed volume under compressive loading and elimination of substantial increases in permeability can be achieved by mechanically compressing the fabric.

Problems solved by technology

However, the use of such coatings presents a disadvantage from both an economic as well as a functional standpoint.

Specifically, the use of coatings may add substantial cost while at the same time adding bulk to the finished product which translates to a greater folded volume of the final configuration thereby requiring a greater allocation of space within the vehicle deployment system.

While such calendering operations may reduce permeability, such operations also generally stiffen the fabric thereby increasing the volume requirements for a packed bag formed on such calendered material.

A problem associated with this practice is once again the fact that the fabric produced may have relatively poor foldability due to the very high number of threads per inch within the woven construction which increases the stiffness and hence the packed volume requirement.

Further, these issues of packing and trouble-free inflation become even more important as complex folding patterns are utilized to control initial impact in instances where an occupant may be directly facing the deploying cushion.

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