JP2001221938A - Flexible cable protective tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible cable protective tube, especially a flexible cable protective tube which is simple in structure and is easy to handle an optical fiber without damaging it. SOLUTION: The tube is provided with a main body part in which a hollow threaded body is formed by helically winding a wire rod and extending it and a coating part consisting of synthetic resin coated on the outer surface of the main body part or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible cable protection tube, and more particularly, to a flexible cable protection tube which has a simple structure and can be easily handled without damaging an optical fiber. About pipes.

[0002]

2. Description of the Related Art In recent years, quartz, plastic or the like has been used as an optical fiber of an optical fiber cable. Since the material of these strands is weak in strength, the optical fiber cable uses a reinforcing material such as Kevlar (trade name of aromatic polyamide fiber) or a tension member, and is made of PE.
A coated polymer-cable optical cable or optical fiber (element wire, core wire, cable, etc.) coated with a metal tube is used. However, the above configuration is hard, inflexible, and poor in workability in consideration of strength safety. For this reason, Japanese Patent No. 2698203 has been proposed as one of the flexible cable protection tubes.

[0003]

As shown in FIG. 2 of Japanese Patent No. 2698203, this cable protection tube is obtained by bending a single band-like plate into an S-shaped cross-section, performing primary processing, and further performing primary processing. A spirally wound protective tube is formed, and an optical fiber is inserted into the protective tube as shown in FIG. 1 of the publication. With this configuration, when an optical fiber cable is manufactured by simultaneously performing the steps of forming the protective tube and inserting the bare fiber into the protective tube, as one example, the inner diameter of the protective tube to be manufactured is substantially equal to the inner diameter of the protective tube to be manufactured. A mandrel having the same diameter is selected, a fiber strand is inserted into an insertion hole provided in the mandrel, and the above-mentioned temporarily processed strip is spirally wound from the periphery of the mandrel.

However, as a result of spirally winding the bent band-shaped plate, the band-shaped plate is again bent. Therefore, when forming a protective tube having a small diameter, there is no difference between the inner diameter of the protective tube and the diameter of the fiber strand, that is, there is no extra width (thickness) for forming the insertion hole provided in the mandrel. It is difficult to manufacture the flexible cable protection tube by simultaneously performing the steps of forming and inserting the fiber strand into the protection tube.

[0005] Therefore, once the protective tube is manufactured, it is necessary to carry out a step of passing a bare fiber through the protective tube by another apparatus disclosed in Japanese Patent Application Laid-Open No. 62-44010.

The present invention has been made in view of the above-mentioned problems, and has a simple structure, can maintain sufficient flexibility, can be sufficiently cut off even under a high tensile force, and has a small diameter. It is an object of the present invention to provide a cable protection tube capable of simultaneously forming a protection tube and passing a bare fiber through the protection tube even for a protection tube.

[0007]

In order to solve the above-mentioned problems, in order to solve the above problem, a wire is spirally wound and extended to form a hollow threaded body, and the outer surface of the body is coated. And a covering portion made of a synthetic resin or the like.

Further, the inner diameter of the main body is x, the diameter of the wire is y, and the thickness of the main body is z, and 0 <y <x and 0 <z <x and 2.75y ≦ z and x ≧ 0 .5 ・
(Y + z) and a loop forming radius satisfying 25 mm or more.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic perspective view of a main part of the cable protection tube, FIG. 2 is a side sectional view of FIG. 1, and FIG. 3 is a front sectional view of FIG.

[0010] The cable protection tube is formed by winding a wire 11 in a helical shape and extending the body to form a hollow threaded body.
And a covering portion 20 made of rubber, synthetic resin, or the like, which covers the outer surface of the main body 10. Coating part 20
Is a main body 1 having a predetermined thickness and a threaded body formed of a resin such as a vinyl chloride resin, a rubber synthetic resin, a polyurethane resin, or a coating material such as an organic polymer material.
0 is coated on the outer surface so that the inner and outer surfaces have a flat annular shape.

In the flexible cable protection tube having such a configuration, a hollow threaded body is formed by spirally winding and extending the wire member 11 of the main body 10, and thereafter, the hollow body is formed. The coating portion 20 is formed by coating the above-described coating material on the outer surface of the threaded body. With such a manufacturing method, the main body 10 can be formed only by spirally winding the wire 11, and the main body 10 having a small diameter can be formed. Along with this, by extending the formed main body 10, a fiber line (not shown) can be sent out at the same time as the above-described steps, and the fiber line as described in the conventional example can be manufactured. There is no need for a separate step of passing through a mandrel having substantially the same diameter as the inner diameter of the main body 10 to be intended.

The above-described method of coating the outer surface of the main body 10 with a coating material is performed by a known method of coating a conduit tube with a coating material. That is, the covering portion 20 is
The outer surface of the formed screw body is coated with the above-described coating material, and the coated coating material is cooled to form the coating portion 20. The covering portion 20 is cooled to form a flexible cable protection tube in a state in which the covering portion 20 is reduced to such a degree that the covering portion 20 slightly bites into the main body 10, that is, in a state where the covering 20 is pressed against the outer surface of the main body 10. The main body 1 due to bending of the flexible cable protection tube.
The buckling of 0 is prevented, and even a high tensile force is sufficiently eliminated. Further, by appropriately selecting the coating material of the covering portion 20, the flexibility of the flexible cable protection tube against bending can be increased.

With such a configuration, when the flexible cable protection tube is subjected to bending deformation, the inside of the flexible cable protection tube is covered with concave and convex concave portions formed on the outer surface of the main body 10. Part of the part 20 is in a state of further biting,
The bite portion regulates the inner shrinkage portion by elastic force which is a part of the material property.

Further, the outside of the flexible cable protection tube is
The portion where the coating material has bitten is locked to the periphery of the concave portion of the main body 10, restricting excessive partial bending (preventing buckling of the main body 10), Irrespective of this, a space in which the fiber wire can move freely is formed.
As a result, the fiber wire comes into contact with the inner wall surface of the main body 10 with a degree of freedom, so that tensile stress is not applied to the fiber wire inserted into the main body 10, and the flexible cable protection tube is repeatedly bent and deformed. Breakage of the fiber wire can be prevented.

The above effects are achieved by the diameter of the main body 10, the material of the coating material to be the coating 20, and the coating 20.
It is determined by the thickness or the like of the main body 10. Particularly, when the inner diameter of the main body 10 is x, the diameter of the wire 11 is y, and the thickness covering the main body 10 is z, 0 <y <X and 0 <z <x and 2.75 · y ≦ z and x ≧ 0.5 · (y + z)
It is desirable to satisfy the condition (1), and by entering the range of this condition, it is possible to make the loop forming radius 25 mm or more. The loop forming radius means the minimum radius of curvature at the time of forming a loop by the method shown in FIG. 4 of Japanese Patent No. 2698203. Specifically, x = 1.5 mm, y = 0.2 mm and z
Assuming that 0.55 mm, the loop forming radius was 35 mm.

[0016]

According to the present invention, it is possible to form a protective tube even when a protective tube having a small diameter can be sufficiently cut off even with a high tensile force while maintaining a simple structure and flexibility. And the step of passing the fiber through the wire at the same time.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a main part of a cable protection tube.

FIG. 2 is a side sectional view of FIG.

FIG. 3 is a front sectional view of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Main body part 11 Wire rod 20 Coating part x Inner diameter of main body part y Diameter of wire rod z Thickness which coats a main body part

Claims (2)

[Claims] 1. A main body in which a wire is spirally wound and extended to form a hollow threaded body, and a coating portion made of a synthetic resin or the like coated on an outer surface of the main body portion. A flexible cable protection tube characterized by the above-mentioned. 2. The internal diameter of the main body is x, the diameter of the wire is y, and the thickness of the main body is z. 0 <y <x, 0 <z <x, and 2.75y ≦ z
2. The flexible cable protecting tube according to claim 1, wherein x ≧ 0.5 · (y + z) and a loop forming radius satisfy 25 mm or more.