JPS62153809A - Branchable optical fiber cable and its laying method - Google Patents

Abstract

PURPOSE:To obtain a branchable optical fiber cable which can lay sets of optical fibers different in use in one construction, by constituting the optical fiber cable with plural optical fibers divided into plural sets and a synthetic resin coating which coats them and has constricted parts between sets of optical fibers. CONSTITUTION:Plural optical fibers 1a and 1b are divided into plural sets, for example, two sets A and B and are arranged on a plane in parallel. These optical fibers 1a and 1b are coated with a common synthetic resin coating 2, and a constricted part 3 continuous in the lengthwise direction is formed in the division part between two sets A and B of the coating 2. Two high-tensile strength members 4a and 4b are provided on both sides of optical fibers 1a of the set A or optical fibers 1b of the set B if necessary. Thus, the optical fiber cable is broken easily in the constricted part 3 of the coating in accordance with the use to separate sets A and B from each other.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a branchable optical fiber cable and its installation method.

<Prior Art> Various optical fiber cables have been proposed in the past. For example, an optical fiber cable disclosed in Japanese Patent Publication No. 58-54361 is known.

<Problems to be Solved by the Invention> However, in such conventional optical fiber cables, although a plurality of optical fibers are divided into groups, in order to branch these groups of optical fibers, it is necessary to coat the optical fibers. The fibers had to be carefully peeled off to extract the divided optical fibers inside, and the work involved in branching was extremely complicated and time-consuming. It is also conceivable to suspend, for example, two independent optical fiber cables, but the installation work would have to be done twice, making the work unavoidably complicated.

The present invention has been made in view of the deficiencies of the prior art, and has a structure in which sets of optical fibers for different uses can be easily branched, and a set of optical fibers for different uses can be laid in a single installation work. The purpose is to provide a fiber cable and its installation method.

Means for Solving the Problems〉 The configuration of the branchable optical fiber cable according to the present invention that achieves the above object includes a plurality of optical fibers divided into a plurality of groups, and a common connection between the plurality of optical fibers. It is characterized by comprising a synthetic resin coating having a constricted portion between the pairs of optical fibers. In addition, another optical fiber cable of the present invention has a structure in which a high tensile strength member is selectively interposed in each set of optical fibers, or a high tensile strength member is interposed in the coarse metal of the optical fiber. This is a characteristic feature.

Moreover, the configuration of the method for laying a branchable optical fiber cable according to the present invention is divided into a plurality of groups. Suspending 1jH optical fibers and a branchable optical fiber cable made of a synthetic resin that commonly coats the plurality of optical fibers and forms a constriction between the sets of optical fibers, At the branching position, the desired set of branchable optical fibers is separated by tearing the constriction of the coating, and the set of branched optical fibers forms a branched optical fiber cable, and the remaining branchable optical fibers are separated. This set is characterized in that it is held rounded at the branch position.

<Example> An example of the branchable optical fiber cable according to the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a branchable optical fiber cable according to the present invention. According to the branchable optical fiber cable according to the present invention, as shown in FIG.
and 1b are divided and arranged in a plane and in parallel. These optical fibers la and lb are commonly coated with a synthetic resin coating 2. The covering 2 forms a constricted portion 3 that is continuous in the longitudinal direction at a portion that separates the 82 pairs A. Furthermore, if necessary, two high tensile strength members 4a and 4b are interposed on both sides of the optical fibers 1a of group A or on both sides of the optical fibers 1b of group B, respectively, to increase the strength of the optical fiber cable. Guaranteed.

It should be noted that these high tensile strength members 4a and 4b are not necessarily required for all optical fiber pairs, and in some cases, they may consist of only optical fibers.

The branchable optical fiber cables according to the present invention may have the same installation route but different applications, and in such cases, it is desirable to complete the construction work only once.

According to the branchable optical fiber cable according to the present invention,
A plurality of pairs of optical fibers la and lb are connected in parallel in the width direction with a single coating, and between each pair, the coating is connected at a constriction 3.
It has a structure that allows it to be easily separated depending on the application because it is thin. Since multiple sets of optical fibers are used for different purposes, the locations where branch connections are desired may differ from each other. In such a case, a desired set of optical fiber cables integrally formed with a common sheath can be easily separated by tearing from the constriction 3 of the sheath, and the branched optical fiber cables can be pulled out and wired to an external circuit. be able to.

FIG. 2 is a diagram illustrating a method of laying a branchable optical fiber cable with branching according to the present invention. According to the method for laying a branchable optical fiber cable according to the present invention,
A. Tear apart the constriction 3 of the sheath provided between two sets of optical fiber cables that can be branched and have 82 sets of optical fiber cables, for example, the optical fibers of set A are split and branched. The optical fiber cables of the other group B wired to the junction box 5 have an extra length equal to the length of the optical fiber cables of the group A when they are pulled out at the branch point.
As shown in FIG. 2, the optical fiber cables of group B may be held at the branching position by rolling up the excess length. still,
It is possible to store the rolled optical fiber cables of group B and the branched optical fiber cables of group A, including the branch connection box, in a portion surrounded by a dotted line in one storage box.

FIG. 3 shows a sectional view of another embodiment of the branchable optical fiber cable of the present invention. The optical fiber cables 1 of the two sets A and B are coated with a common synthetic resin such as polyethylene, and the covering 2 forms a constricted part 3 in the middle part of the two sets. In the optical fiber cable of group A in FIG. 3, a high tensile strength member 6a is arranged at the center, and optical fibers 1a are arranged at equal intervals around the member. The outer periphery of the circularly arranged optical fibers 1a is filled with a cushioning material 7, and a tape 8 is wound around the material 7 to form the core of the A-all optical fiber cable.

Similarly, in the optical fiber cable of group B, the optical fibers 1b are arranged in a circle at equal intervals around a high tensile strength member 6b disposed inside, the outer periphery is filled with a cushioning material 7, and the outer periphery is filled with a tape 8. are wound to form the core of the 8-pair optical fiber cable. The cable cores of groups A and B are commonly molded with a synthetic resin coating 2.

Note that a constriction 3 of the coating 2 is formed at the intermediate portion of the two sets of optical fiber cables, making it easy to branch.

The method of installing the branchable cable of the present invention shown in FIG. 3 is carried out in the same manner as shown in FIG.

<Effects of the Invention> According to the branchable optical fiber cable according to the present invention,
In cases where the route is the same but the purpose is different, for example when used as an addition to an overhead power transmission line, one set of fiber optic cables is used for optical data communication, and the other set of fiber optic cables is used for the tower. It is convenient because it can be branched into each section and used to collect tower information. In addition, when installing the optical fiber cable according to the present invention, one optical fiber cable used for collecting tower information is branched at a necessary point and routed to a branch junction box, and the remaining optical fiber cable is routed to the branch position. By holding the fibers rolled up, the optical fiber installation work for the entire length of the long line can be done only once, making the work simple, and the cost required for it is also low, making it extremely economical.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of a branchable optical fiber cable according to the present invention, and FIG. 2 is an explanatory diagram for explaining a method for laying a branchable optical fiber cable according to the present invention.
FIG. 3 is a sectional view of another embodiment of the branchable optical fiber cable of the present invention. In the drawing, la and lb are optical fibers, 2 is a coating, 3 is a constriction, and 4 is an optical fiber.
a, 4b are high tensile strength members, 5 is a branch connection box, 6a, 6b
is a high tensile strength member, 7 is a cushioning material, and 8 is a tape.

Claims (8)

[Claims] (1) A plurality of optical fibers divided into a plurality of sets, and a synthetic resin coating that commonly covers the plurality of optical fibers and forms a constriction between the sets of optical fibers. A branchable optical fiber cable comprising: (2) The branchable optical fiber cable according to claim 1, wherein each set of optical fibers includes a plurality of optical fibers arranged in a plane and in parallel. (3) The branchable optical fiber cable according to claim 1, wherein a plurality of optical fibers are arranged in a circle for each set of optical fibers. (4) A plurality of optical fibers divided into a plurality of sets, and a synthetic resin coating that commonly covers the plurality of optical fibers and forms a constriction between the sets of optical fibers. A branchable optical fiber cable comprising: a high tensile strength member interposed in at least one of the sets of optical fibers in juxtaposition to the optical fibers. (5) The branchable optical fiber cable according to claim 4, wherein a plurality of optical fibers are arranged in a plane and in parallel for each set of optical fibers. (6) The branchable optical fiber cable according to claim 4, wherein a plurality of optical fibers are arranged in a circle for each set of optical fibers. (7) The branchable optical fiber according to claim 6, wherein in each set of optical fibers, a plurality of optical fibers are arranged in a circle around the high tensile strength member. cable. (8) A plurality of optical fibers divided into a plurality of sets, and a synthetic resin coating that commonly covers the plurality of optical fibers and forms a constriction between the sets of optical fibers. A branchable optical fiber cable made of A method for laying a branchable optical fiber cable, characterized in that the remaining set of the branchable optical fibers is rolled up and held at the branching position.