Textiles: weaving – Fabrics – Materials
Reexamination Certificate
2002-08-07
2004-08-10
Calvert, John J. (Department: 3765)
Textiles: weaving
Fabrics
Materials
C139S4260TW, C442S203000, C297S464000
Reexamination Certificate
active
06772797
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to webbing for a seat belt, which is woven in a belt like configuration by making warp yarns cross with weft yarns.
More particularly, the invention relates to a technique of obtaining a thin and light webbing having a high strength per unit numbers of warp yarns and maintaining abrasion resistance, which is woven by using, as warp yarns, polyester multifilament yarns each made by very-strong, fine single filament yarn which are not typically used in a conventional seat belt and are highly twisted very much with a twisting condition, unlike in the conventional seat belt.
2. Description of Related Arts
Generally, a webbing for a seat belt has specifications assuring characteristics such as specified tensile strength, elongation, and durability or the like, and it mainly uses, as warp yarns, multifilament yarns made of polyester or polyamide filament yarns or fibers and, as weft yarns, multifilament yarns or monofilament yarns made of polyester or polyamide filament yarns of fibers, and is woven into a belt like narrow fabric by making the warp and weft yarns intercrossed with each other on a loom for a narrow fabric.
Conventionally, most of webbings are woven into a belt like narrow fabric on a power loom for a narrow fabric by making warp and weft yarns intercrossed with each other by reciprocating a shuttle for weft yarns along a shedding portion provided within the warp yarns and formed by an upper warp yarn group and a lower warp yarn of the total warp yarn group and separated from each other, on the loom.
During the weaving operation of the power loom for a narrow fabric, due to abrasion to the warp yarn group by the shuttle for weft yarns which passes through the shedding portion formed by the upper warp yarn group and a lower warp yarn of the warp yarns on the loom, damage such as a breakage in a filament often occurs on the warp yarn group.
To prevent the breakage in a filament of the warp yarn group, conventionally, a multifilament yarn made of polyamide, which has a single yarn fineness of about 8 deniers and a strength thereof being about 8 g per denier and is twisted up to about 80 turns/m, had been generally used as a warp yarn in a webbing.
After that, a weaving process for making webbing by utilizing a needle loom for a narrow fabric has become popular. In the weaving, by reciprocating a needle for weft yarns along the shedding portion formed by separated upper warp yarn group and lower warp yarn group on the loom, the warp yarns and the weft yarns are intercrossed with each other so as to farm a belt like configuration.
Abrasion to the warp yarn group caused by the needle for weft yarns, which passes through within the shedding portion formed by the separated upper warp yarn group and lower warp yarn group, on the loom, during the weaving operation by the needle loom for narrow belt like fabric, is much smaller than that to the warp yarns caused by the shuttle for weft yarns used in a power loom.
Therefore, without maintaining binding characteristics of yarns by giving certain numbers of twist in the warp yarns, the damages such as the breakage in a filament does not occur so much on the warp yarn group. Consequently, the tendency of reducing the cost of a webbing by eliminating the coat of the twisting process by skipping the twisting process of the warp yarns, which is conventionally performed, became stronger.
Further, along with the above-mentioned tendency of not performing the twisting process, a new method for sec wing abrasion resistance of a webbing by performing a surface finishing process using a resin, oil, or the like on the webbing woven by using, as warp yarns, multifilament yarns of which single yarn fineness is large, was created and this technique has been often used.
As a result, it became common to use, as a warp yarn, a multifilament yarn made of polyamide or polyester, almost without being twisted, and having a single yarn fineness of about 11 deniers and a strength of about 8.5 g per denier.
Note that, recently, a polyester fiber is used in most of webbings and thus it becomes a mainstream in manufacturing a webbing, to weave a webbing on a needle loom for a narrow fabric by using, as a warp yarn, a polyester multifilament yarn having a single yarn fineness of about 11 deniers and a strength of about 9 g per denier.
Further, recently, with advance in the technique of making polyester yarns in which the yarn can maintain conventional yarn strength although a single yarn fineness thereof is large, and in which filaments are seldomly broken, in order to omit a surface finishing process to the yarns for maintaining abrasion resistance of the webbing, there is a tendency to further enlarge the mingle yarn fineness of a fiber used for a warp yarn in the webbing.
It is recommended to use, as a warp yarn in a webbing, a polyester multifilament yarn having a single yarn fineness of about 14 deniers and a yarn strength of about 9 g per denier with an almost no-twist.
As in the transition of the conventional technique, the needle loom for a narrow fabric has come to be generally used for weaving of webbing. As the yarn-spinning technique advances and as a fiber manufacturer has come to be able to supply a polyester multifilament which is hardly broken and has a large single yarn fineness, that was difficult to be achieved in the past, the webbing manufacturing technique has been shifted to the direction of omitting the process of twisting the warp yarn in a webbing to reduce the cost of the webbing and of increasing the fineness of a single yarn of a polyester filaments or fibers used for a warp yarn to secure abrasion resistance by omitting a surface finishing treatment process.
On the other hand, the higher the drawing ratio of a filament or fiber becomes, the higher the strength becomes. On the contrary, occurrence of breakages in a filament increases.
As the fineness of a single yarn is increased, the drawing process in a yarn spinning process becomes difficult. It is that the yarn speed of yarn spinning process decreases to keep a predetermined quality.
Even by utilizing the present yarn-spinning technique which is the to be highly advanced, it is very difficult to further improve the strength of the fiber by increasing the drawing ratio or to further reduce the cost of a source yarn by increasing the yarn-spinning speed without increasing the occurrence of failures, for example, generation of yarn break or the like in the filament of the polyester multifilament yarn or fiber having an increased single yarn fineness which is being often used recently as the warp yarn in a webbing.
On the other hand, in a weaving process, a polyester multifilament yarns having a large single yarn fineness and almost without being twisted, is used for the warp yarns in a webbing.
Therefore, the drawback caused by yarn breakages in the filaments becomes a drawback of a webbing in that a cut cad portion of a single filament or fiber having a relatively large fineness is projected from the surface of the woven webbing, and is apparent as a failure in the appearance of the webbing.
From the viewpoint of suppressing a failure in the webbing, frequent occurrence of the failure of yarn breakages in the filament in the yarn-making process cannot be accepted, while, it is difficult to pursue reduction in the cost of the source yarn by increasing the strength of the filament or the fiber or by increasing the yarn-making speed.
Therefore in the direction of the recent webbing weaving technique of increasing the fineness of a single yarn as well as of omitting the process of twisting the polyester yarns used for the warp yarns of a webbing, it is difficult to reduce the cost of the source yarn by improving the speed of spinning a yarn in the yaw-spinning process or to reduce the cost of the source yarn by improving the strength of the source yarn by increasing the drawing ratio. The techniques have reached the highest limit and the next task is to develop a novel technique to look for a remar
Calvert John J.
Greer Burns & Crain Ltd.
Kikuchi Kogyo Co., Ltd.
Muromoto Jr. Robert H.
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