JPH01271708A - Method of laying winding type aerial optical fiber cable - Google Patents

Abstract

PURPOSE:To maintain reliability over a long period of time by winding a winding type aerial optical fiber cable by such winding tension as to eliminate the slack of optical fibers generated by winding to an aerial wire without untwisting the cable, thereby laying the cable. CONSTITUTION:Plural pieces of the optical fibers 2 which are disposed with a central tensile body 10 at need at its center and has a covering thereon are double and twisted in, for example, left-hand lay, and are applied with retaining winding, etc. The winding type aerial optical fiber cable 4 provided with a sheath 3 is wound around the aerial wire 5 in right-hand lay, reverse from the doubling and twisting direction of the optical fibers 2 without untwising. The winding tension of the winding type aerial optical fiber cable to the aerial wire 5 is adjusted to such value as to release the doubling and twisting state of the optical fibers 2 and to eliminate the slack thereby by reversing the doubling and twisting and winding direction of the optical fibers 2. The generation of the tensile strain of the optical fibers 2 and the deterioration in the temp. characteristics after laying is thereby eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method of winding and laying an optical fiber cable around an overhead line such as an overhead power transmission line or an overhead ground wire.

[Prior art]

Conventionally, as shown in FIG. 2, for example, a wrapped-type aerial light beam is constructed by twisting together a plurality of optical fiber cores 2 having a coating around a central tensile strength member 10 made of FRP or the like, and applying a sheath 3 or the like to this. When installing the fiber cable 4 by wrapping it around the overhead wire 5 as shown in FIG. 3, it is usually untwisted as shown in FIG. The optical fibers 2 are wound in such a way that the twisted state, etc. of the optical fibers 2 are not changed as much as possible. In this figure, reference numeral 1 denotes a supply bobbin around which a wrapped aerial optical fiber cable 4 is wound.The supply bobbin is usually used in an aerial manner, and the wrapped aerial optical fiber cable 4 is rotated around vI5 while twisting 360°. A fiber cable 4 is supplied and wound around an overhead wire 5. Note that although four supply bobbins 1 are drawn in this figure, this shows the locus of one supply bobbin 1.

However, in the above-mentioned method, since it is necessary to twist the yarn back, there is a problem in that the mechanism of the entire device becomes complicated and large in size. In addition, when wrapping the existing overhead wire 5, the large-scale wrapping requires transporting the device to the steel tower, which poses problems in that this work is large-scale and highly dangerous.

On the other hand, in order to simplify the equipment, the winding is done without twisting the overhead wire 5.
For example, when trying to wrap a wrap-type aerial optical fiber cable 4 around a wrap-type overhead optical fiber cable 4, for example, the twisting direction of the optical fiber cores 2 in the wrap-type overhead optical fiber cable 4 and the cable 4
When the directions of winding around the overhead wire 5 are the same, the twisted state of the optical fiber coated wire 2 is tightened, and as a result, tensile strain is generated in the optical fiber coated wire 2.

If extra tensile strain is already present at the time of installation,
When a tensile force or the like is applied to the wrapped overhead optical fiber cable 4 after installation, there is a problem in that the transmission loss of the optical fiber increases rapidly.

- If the twisting direction of the destination fiber coated wire 2 and the winding direction around the overhead wire 5 are opposite, the twisted state of the optical fiber coated wire 2 will become loose, and the temperature of the optical fiber coated wire 2 after installation will increase. There was a problem that the properties, especially the low temperature properties, deteriorated.

The reason for this is that when the strands are loosely twisted, the shrinkage force caused by the contraction of the coating of the optical fiber core 2 at low temperatures tends to accumulate locally, compared to when the strands are tightly stranded. Buckling becomes more likely to occur in the optical fiber.As a result, it is assumed that the transmission loss of the optical fiber increases.

[Object of the Invention] In view of the above-mentioned problems, the object of the present invention is to provide a method for installing a wrapped overhead optical fiber cable onto an overhead line without twisting it back.
It is an object of the present invention to provide a laying method that does not cause tensile strain in an optical fiber core wire due to winding and also does not cause deterioration of temperature characteristics after laying.

[Structure of the invention]

In order to achieve the above-mentioned object, the present invention involves winding a wrapped overhead optical fiber cable formed by twisting a plurality of optical fibers around the overhead wire in a direction opposite to the direction in which the optical fibers are twisted together. In the installation method, the above-mentioned wrapped overhead optical fiber cable is not twisted, and the winding is carried out using tension to eliminate the slack of the optical fiber core wire caused by winding it around the above-mentioned overhead wire. It is characterized by being wrapped and laid.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below with reference to the drawings.

In the installation method of the present invention, for example, as shown in FIG. 2, a central tensile strength member 10 such as FRP is arranged at the center as necessary, and a plurality of coated optical fibers 2 are attached to this central tensile strength member 10, and
Now, for example, after twisting the left-handed twisted fibers and applying pressure winding or the like as necessary, a wound type aerial optical fiber cable 4 with a sheath 3 made of polyethylene, polyvinyl chloride, etc. is made as shown in Fig. 1. As shown, the optical fiber core wire 2 is twisted clockwise around the overhead wire 5, opposite to the direction in which it is twisted.
Moreover, the winding is performed without untwisting, and at this time, the winding type overhead optical fiber cable 4 is wound around the overhead wire 5 under tension, and the twisting direction and winding of the optical fiber core wire 2 are adjusted. Considering that the twisted state of the optical fiber coated wire 2 is loosened by reversing the direction, and sag occurs in the optical fiber coated wire 2, a value that eliminates this slack,
In other words, it is characterized in that it is set to a value that substantially cancels out this slack.

Although four supply bobbins 1 are depicted in FIG. 1, this is drawn to show the locus of one supply bobbin. As shown in this figure, winding without twisting means rotating the supply bobbin 1 around the overhead wire 5 with the collar 18 of the supply bobbin 1 always facing the overhead wire 5. There is.

As described above, in the method for installing a wrapped overhead optical fiber cable of the present invention, the twisting direction of the optical fiber core wires in the wrapped overhead optical fiber cable is changed when the cable is wound around the overhead wire. By reversing the direction, the twisted state of the optical fiber core wires is prevented from tightening, that is, the generation of tensile strain caused by winding around the overhead wire is prevented, and on the other hand, when this winding loosens, The expected twisting state of the optical fibers is also canceled out by selecting an appropriate winding tension.

As a result, no tensile strain occurs in the optical fiber core wire due to winding, and the low-temperature characteristics after installation are not deteriorated.

In the above embodiment, the optical fibers are twisted in the left-handed direction, and the winding around the overhead wire is twisted in the right-handed direction, but the same effect can be obtained even if the former is twisted to the right and the latter is twisted to the left It goes without saying that this effect can be obtained.

〔Effect of the invention〕

As described above, according to the method for installing a wrapped overhead optical fiber cable of the present invention, the twisted state of the optical fiber cores in the cable does not become tight or loosen even when wrapped around an overhead wire. Therefore, no tensile strain occurs due to wrapping around an overhead wire, and the temperature characteristics after installation do not deteriorate. That is, high reliability can be maintained over a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of a winding method for wrapping an overhead optical fiber cable around an overhead line according to the present invention;
The figure is a cross-sectional view showing an example of a wrap-type overhead optical fiber cable according to the present invention, FIG. 3 is a schematic diagram showing a state in which the wrap-type overhead optical fiber cable is wound around an overhead line, and FIG. Conventional winding is a schematic diagram illustrating the method. 2 ~ Optical fiber core wire 4 ~ Wound type overhead optical fiber cable 5 ~ Overhead wire patent applicant Furukawa Electric Co., Ltd. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A method of installing a wrapped overhead optical fiber cable formed by twisting a plurality of optical fiber cores around an overhead wire in a direction opposite to the direction in which the optical fiber cores are twisted together, A winding type characterized in that the optical fiber cable is laid without being twisted, but with a winding tension that eliminates the slack in the optical fiber core wire caused by winding it around the overhead wire. How to install aerial fiber optic cables.