JPH02240603A - Aerial laying method for optical cable - Google Patents

Abstract

PURPOSE:To allow the easy and safe laying of an optical cable by first laying a pipe along the existing aerial wire, then introducing the optical cable therein. CONSTITUTION:Split bobbins 2 are first mounted on the outer periphery of the existing aerial wire 1 and the pipe 3 of the required length is wound on this bobbin 2. A rope 4 for taking off and a counter weight 5 for preventing rotation are mounted to the front end of the pipe 3 and the rope 4 is pulled toward the aerial wire 1 and is laid in the form of winding the pipe 3 spirally on the aerial wire 1. The bobbin 2 is removed from the aerial wire 1 after the laying of the pipe. The optical cable 6 is thereafter introduced by a pneumatic feeding method, etc., into this pipe 3. The easy and safe aerial laying of the optical cable is executed in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for laying optical cables over the air, and particularly to a method suitable for laying thin optical cables over the air.

[Prior art]

One method for installing optical cables overhead is to attach the optical cables to existing overhead lines.

This method uses already installed overhead lines such as power lines, communication lines, and mensenger wires, and attaches the optical cable there vertically using lashing wires or hangers, or wraps it using a machine. It is something to do.

〔assignment〕

However, since this method involves directly attaching an optical cable to an overhead line, optical cables with low mechanical strength are likely to be damaged. For example, optical fiber cables for subscribers that are drawn into each home from utility poles have a small number of fibers and are not strong, so if you try to attach them to power lines using the method described above, it is difficult to handle them without damaging them. Not only that, but in some cases, too much tension may be applied, causing an increase in transmission loss or breakage.

(Means for Solving the Problems and Their Effects) In view of the problems of the prior art as described above, the present invention provides a method for installing an optical cable overhead without causing any damage to the optical cable. When installing an optical cable overhead along an overhead line, this special method is characterized by first installing a pipe along the overhead line and then introducing the optical cable into the pipe. By attaching an optical cable to an overhead line, there is no risk of damage to the optical cable due to various external forces that occur during attachment, and by later introducing the optical cable into the attached vibe, the optical cable can be easily and safely installed overhead. It is designed so that it can be installed.

The pipe attached to the overhead line only needs to have at least one hole for introducing the optical cable. The number of pipes to be added may be one or more. The optical cable may be introduced into the pipe by any method such as a pulling method, a pushing method, or a pressure feeding method using a fluid.
The air pressure feeding method disclosed in Japanese Patent Laid-Open No. 59-104607 is suitable.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. In this method, first, a halved bobbin 2 is attached to the outer periphery of an existing overhead line 1, and a pipe 3 of a required length is wound around this bobbin 2. Next, a lobe 4 for take-up and a counterweight 5 for preventing rotation are attached to the tip of the pipe 3, and the lobe 4 is pulled in the direction of the overhead line 1, so that the pipe 3 is wound around the overhead line 1 in a spiral shape. erect it. The bobbin 2 is removed from the overhead wire 1 after the vibrator is installed. It is recommended that both ends of the installed pipe 3 be fixed to the overhead line 1 using appropriate tightening members to prevent it from coming apart.After that, the pipe 3 is inserted into the pipe 3 using an air pressure feeding method or the like as shown in Figure 4. An optical cable 6 is introduced. This completes the overhead optical cable installation.

A normal pipe can be used as pipe 3, but as shown in Fig.
As shown in 3(a), a plastic molded body 9 having a 68 for introducing an optical cable is integrally formed around the outer periphery of a central tension member 7 made of FRP or the like, or a A plastic sheath 1 is placed around the outer periphery of a plastic spacer 11 having a plurality of grooves 10.
It is also possible to use a device in which 2 are provided integrally.

In order to make it easier to pull out the pipe 3 from the bobbin 2, the bobbin 2 should omit the collar on the side from which the pipe 3 is pulled out, and the body should have a taper that decreases in diameter in the direction in which the pipe 3 is pulled out. . In addition, it is possible to make the pipe 3 easier to pull out by constructing the bobbin 2 and the pipe 3 with a material with good slipperiness, or by applying a slippery material such as oil or powder to the bobbin 2 and the pipe 3. This is effective.Furthermore, if a pipe 3 with high rigidity or with a spiral shape memorized in advance is used, the friction between the overhead wire 1 and the pipe 3 will be reduced, and the pipe 3 can be laid over a long distance.

In addition, since the optical cable 6 is only subjected to a slight external force during installation, it can be constructed by covering a plurality of optical fiber cores 13 with a plastic sheath 14 as shown in Figure 4(a), or by covering it with a plastic sheath 14 as shown in Figure 4(G). As shown, a relatively simple structure can be used, such as one in which a plurality of optical fiber cores 13 are held down at 15.

FIG. 2 shows another embodiment of the present invention. This embodiment is a laying method when a branch line 1a is connected to the middle of the overhead line 1. Here, pipe 3 has a memorized spiral shape.
Wind the pipe 3 on one side of the branch line 1a around the split bobbin 2 attached to the overhead line 1, and when it has been wound halfway, position the winding start end of the pipe 3 on the opposite side of the branch line 1a. , Wrap pipe 3 around bobbin 2.

Then, a coiled bundle of pipes 3 is formed on both sides of the branch line 1a, so if both ends of the pipe 3 are pulled in opposite directions by the lobe 4, a continuous pipe 3 is wound around the overhead wire l on both sides of the branch line 1a. can be installed. After that, the optical cable is introduced into the vibrator 3.

In the above embodiments, the pipe was laid so as to be wound around the overhead line in a spiral manner, but the present invention is not limited to this. For example, the pipe may be laid by a method such as wrapping a lancing wire while vertically supporting the pipe around the overhead line. You can also do it.

〔Effect of the invention〕

As explained above, according to the present invention, a pipe is first laid along an existing overhead line, and then an optical cable is introduced into the pipe, so that the optical cable can be laid easily and safely. It is extremely effective for laying optical cables, which are particularly weak in strength, overhead without damaging them.

[Brief explanation of drawings]

Figures 1 and 2 are explanatory diagrams showing an embodiment of the optical cable overhead installation method according to the present invention, and Figure 3 is a fat (b
) is a sectional view showing a specific example of a vibrator used in the installation method, and FIG. 4: Rope, 6: Optical gable. Figure 3

Claims (1)

[Claims] 1. A method for installing an optical cable overhead along an existing overhead line, which is characterized in that a pipe is first installed along the above-mentioned overhead line, and then the optical cable is introduced into the pipe. Method.