Textiles: spinning – twisting – and twining – Strand structure
Reexamination Certificate
1999-02-19
2001-02-06
Lindsey, Rodney M. (Department: 3741)
Textiles: spinning, twisting, and twining
Strand structure
C057S206000
Reexamination Certificate
active
06182432
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a linear and flexible article designed to pull in and dispose through a protective conduit a cable such as a power cable, a telephone line or an optical-fiber cable. The linear articles of this kind are called “hauling cords” or “fish tapes” in the industries (and the former name will be used herein).
2. Prior Art
FIG. 10
shows a typical example ‘T’ of such hauling cords, as disclosed in the Japanese Utility Model Publication No. Sho.61-22424 (issued in 1986). This hauling cord ‘T’ usually consists of three extruded and drawn polyester resin filaments
01
, wherein these filaments have been intertwisted and simultaneously hot set to permanently maintain their twisted configuration like a three-ply thread. Another Utility Model Publication No. Hei. 4-16566 (issued in 1992) discloses a modified hauling cord. The three filaments constituting this intertwisted hauling cord are bonded together along and at their regions that are in contact with each other, to thereby provide a substantially integral linear member.
FIG. 11
illustrates how to use such an intertwisted hauling cord ‘T’. A flexible wire ‘Y’ may be connected at its one end by a cylindrical joint ‘S’ to one end of the hauling cord. A guiding end ‘G’ having a hole ‘h’ for holding the cable may be attached to the other end of the relatively short flexible wire ‘Y’, to thereby form a finished hauling cord for commercial and practical use. However for the purpose of simpler and concise description, the unfinished cords to which any additional wire etc. have not yet been attached will herein be referred to simply as “hauling cords”.
Those three-ply type prior art hauling cords ‘T’ have been employed long, widely and conveniently since the application date of the first mentioned Utility Model first mentioned above. However, the protective conduits for the various cables have recently been increasing their length and nowadays those conduits are often bent in a complicated fashion. As a result, it has been required these days not only to elongate each hauling cord but also to render same lighter in weight and easier to use and improve its compression strength as well as its tensile strength.
SUMMARY OF THE INVENTION
The present inventor has made studies and conducted researches to meet such recent requirements. An object of the present invention is thus to provide a hauling cord whose overall weight and volume are not raised and whose compression strength is nevertheless improved as compared with the prior art three-ply cords so as to enable it to be forced in and through any elongated conduits.
In order to achieve this object, a synthetic plastic resin will be extruded to form a monofilament of a polygonal cross section and then drawn and self-twisted (not “intertwisted”) to provide a hauling cord in such a manner that the cord has a helical ridge along it and around an outer periphery thereof.
Preferably, the hauling cord may have at least one end region where a pitch of the helical ridge is smaller than that in other regions of said cord.
Alternatively, the hauling cord may have at least one end region made thinner than other regions of said cord.
In practice of the present invention, it is desirable that the polygonal cross section of the monofilament is of a regular configuration such as an equilateral triangle, a regular square, a regular pentagon, a regular hexagon or the like. However, the cross section of the body of hauling cord may alternatively be of an irregular configuration insofar as it has at least one helical ridge.
The region where the pitch of helical ridge is reduced by a stronger twisting may be disposed at either of or both the longitudinal ends of the cord.
Likewise, the thinner region may be disposed at either or both the longitudinal ends of the cord. Such a region or regions may be twisted more times than the remaining mediate region.
REFERENCES:
patent: 2799133 (1957-07-01), Rose
patent: 3023483 (1962-03-01), Steiner
patent: 3205648 (1965-09-01), Lohrke
patent: 4333306 (1982-06-01), Yamashita
patent: 4805393 (1989-02-01), Reta
patent: 4827708 (1989-05-01), Verrect
patent: 61-22424 (1986-07-01), None
patent: 4-16566 (1992-04-01), None
Jordan and Hamburg LLP
Lindsey Rodney M.
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