JPH0652738A - Manufacture of optical fiber composite overhead earth wire - Google Patents

Abstract

PURPOSE:To prevent an increase in transfer loss by preventing a metal tube disposed inside from being contracted in the longitudinal direction by means of a metal wire as an outer layer after an optical fiber composite overhead earth wire has been twisted, and preventing fine bending of optical fiber. CONSTITUTION:When a metal wire 3 is twisted around a metal tube 2 containing optical fiber therein so as to manufacture an optical fiber composite overhead earth wire 11, feed-out capstans 10 are interposed between a supply drum 5 and a wire twisting machine 6. The feed-out capstan 10 applies a back tension to the metal tube 2 in such a manner as to provide the same extension as that due to back tension of the metal wire 3 and an increase in temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical fiber composite overhead ground wire used as an overhead ground wire for an overhead power transmission line.

[0002]

2. Description of the Related Art A general example of an optical fiber composite overhead ground wire is shown in FIG. This optical fiber composite overhead ground wire 11 is obtained by twisting a metal wire 2 having a cable-shaped optical fiber 1 twisted around a metal wire 3 having a segmented cross section, and twisting a metal wire 4 having a circular cross section around the metal wire 2. Is.

An aluminum tube is generally used as the metal tube 2, and an aluminum-coated steel wire is generally used as the metal wires 3 and 4. In the example of FIG. 2, the metal wire has two layers, but the metal wire may have only one layer. When the metal wire has two layers, the metal wire 4 of the outer layer may be a metal wire having a segmented cross section.

Next, a conventional method of manufacturing such an optical fiber composite overhead ground wire will be described with reference to FIG. When there is only one layer of metal wire (when there is no outer layer metal wire 4 in FIG. 2)
Sends out the metal tube 2 accommodating the optical fiber 1 from the supply drum 5, and the metal wire 3 is wound around the metal tube 2 by the twisting machine 6.
Are twisted together to form the optical fiber composite ground wire 11,
The optical fiber composite overhead ground wire 11 is taken up by a capstan 7 and wound around a winding drum 8.

When the metal wire has two layers (in the case of FIG. 2)
Sends out the inner layer stranded wire 9 in which the metal wire 3 is twisted to the outer circumference of the metal tube 2 accommodating the optical fiber 1 from the supply drum 5, and twists the metal wire 4 by the twisting machine 6 to the outer circumference thereof. A composite overhead ground wire 11 is formed, and this optical fiber composite overhead ground wire 11 is taken up by a capstan 7 and wound on a winding drum 8.

[0006]

When twisting a metal wire around the outer circumference of a metal pipe or inner layer stranded wire, a preform or a strong back tension is applied to the metal wire in order to make the twist firm and firm. Further, when the metal wires to be twisted have a cross-section segment type, a forming process from a wire having a circular cross-section to a wire having a cross-section segment shape is performed at the time of twisting, so that the temperature of the metal wire rises.

For this reason, the metal wires of the outer layer are twisted in a stretched state due to back tension and temperature rise. On the other hand, since the metal tube or the inner layer stranded wire is supplied in a state of almost no tension, when twisted up, the phenomenon that the inner metal tube or the inner layer stranded wire is contracted in the longitudinal direction due to the contraction of the outer layer metal wire. . This phenomenon is a preferable phenomenon in that the extra length of the optical fiber is relatively increased, but if the extra length becomes too large, the optical fiber is bent and accommodated in a fine state, and the optical transmission loss increases. .
It is difficult to suppress the increase of the transmission loss by the conventional manufacturing method.

[0008]

SUMMARY OF THE INVENTION The present invention provides a method for manufacturing an optical fiber composite overhead ground wire which solves the above-mentioned problems, and has a structure in which an outer circumference of a metal tube accommodating an optical fiber is provided. In a method for manufacturing an optical fiber composite overhead ground wire by twisting one or more layers of metal wires, a supply drum for supplying the metal tube or an inner layer twisted wire in which the metal wires are twisted around the outer circumference of the metal tube, A sending capstan is installed between the metal pipe or the inner layer stranded wire and the twisting machine for twisting the metal wires, and the metal pipe or the inner stranded wire is twisted around the outer circumference by the sending capstan. The feature is that the back tension is applied so as to give the same degree of elongation as the back tension of the wire and the increase due to the temperature rise.

[0009]

[Function] By applying back tension to the metal tube or inner layer stranded wire that accommodates the optical fiber and giving the same degree of extension as the extension of the metal wire to be twisted to the outer circumference, the contraction after twisting up causes the inside of the stranded wire to shrink. Since it is almost the same outside, it is possible to prevent fine bending of the optical fiber and increase in transmission loss.

As a means for applying back tension to the metal pipe or the inner layer stranded wire, a method of applying a brake to the supply drum can be considered. However, if a metal pipe containing an optical fiber is supplied by this method, the supply drum will be damaged due to the tension. The metal pipe may be bitten or the metal pipe may be crushed. Further, when supplying the inner layer stranded wire, it is necessary to apply a large back tension, but the supply drum cannot apply a large back tension. Therefore, in the present invention, a delivery capstan is installed between the supply drum and the twisting machine, and back tension is applied to the metal pipe or the inner layer twisted wire by the delivery capstan.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to FIG. In the manufacturing method of the present invention, the sending capstan 10 is installed between the supply drum 5 and the twisting machine 6, and the sending capstan 10 is provided with the metal tube 2 containing the optical fiber or the inner layer twisting sent from the supply drum 5. Wrap the wire 9 several times and send out the capstan 10
Back tension is applied to the metal tube 2 or the inner layer stranded wire 9 by applying a brake to the. In this way, the metal wire 3 or 4 is twisted by the twisting machine 6 around the outer circumference of the metal tube 2 or the inner layer twisted wire 9 which is back tensioned, and the twisted optical fiber composite overhead ground wire 11 is taken up by the capstan 7. It is taken up and wound on the winding drum 8.

The magnitude of the back tension applied to the metal tube 2 or the inner layer stranded wire 9 depends on the size of the metal wire 3 to be twisted thereon.
Alternatively, the metal tube 2 or the inner-layer stranded wire 9 has a size similar to the expansion caused by the back tension and the temperature rise of No. 4 described above. In this way, since the contraction after being twisted up is approximately the same inside and outside the twisted wire, it is possible to prevent fine bending of the optical fiber and prevent an increase in transmission loss.

[0013]

As described above, according to the present invention, a feeding capstan is provided between the supply drum and the twisting machine, and the feeding capstan causes back tension to the metal tube or the inner layer twisted wire containing the optical fiber. And
Since the elongation is controlled so as to be approximately the same as the metal wire twisted on it, the inner metal tube or the inner layer twisted wire will not be contracted in the longitudinal direction by the outer layer metal wire after twisting, Therefore, there is an advantage that fine bending of the optical fiber can be prevented and an increase in transmission loss can be prevented.

[Brief description of drawings]

FIG. 1 is a line configuration diagram showing an embodiment of a method for manufacturing an optical fiber composite overhead ground wire according to the present invention.

FIG. 2 is a cross-sectional view showing an example of an optical fiber composite overhead ground wire.

FIG. 3 is a line configuration diagram showing a method of manufacturing a conventional optical fiber composite overhead ground wire.

[Explanation of symbols]

 1: Optical fiber (cable form) 2: Metal tube 3, 4: Metal wire 5: Supply drum 6: Stranding machine 7: Take-up capstan 8: Winding drum 9: Inner layer twisted wire 10: Sending capstan 11: Light Fiber composite overhead ground wire

Claims (1)

[Claims] 1. A method for producing an optical fiber composite overhead ground wire by twisting one or more layers of metal wires around the outer circumference of a metal tube accommodating an optical fiber, wherein the metal tube or the outer circumference of the metal tube has a metal. A supply drum is provided between the supply drum for supplying the inner-layer twisted wire in which the wires are twisted, and a twisting machine for twisting the metal wires on the outer periphery of the metal pipe or the inner-layer twisted wire, and the sending capstan is used to Manufacture of an optical fiber composite overhead ground wire characterized by applying back tension to a metal tube or an inner layer stranded wire so as to give the same degree of elongation as the back tension of a metal wire twisted around its outer circumference and the temperature rise. Method.