JP2002365499A - Self-supporting optical cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a self-supporting optical cable which is capable of effectively shutting off the infiltration of an electric current into a house through a cable in spite of a lightning strike to the cable and preventing the destruction of the apparatus in the house by suppressing the generation of eddy currents. SOLUTION: This self-supporting optical cable has coated optical fibers 11, an optical cable body 13 having a sheath 12 to protect the fibers and a supporting wire 14 for supporting the optical cable body 13 by being placed along the same. The supporting wire 14 is composed of a tensile body made of metal and the optical cable body 13 is composed of a non-metallic body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a self-supporting optical cable.

[0002]

2. Description of the Related Art In recent years, with the increase in communication speed, optical cables have been moved from a termination box near a telephone pole located outdoors to a house (in a house).
It has come to be pulled in and laid. Conventionally, a general structure of a self-supporting type optical cable (or a drop type optical cable) used for this kind of application is, as shown in FIG. An optical cable main body 3 having an outer jacket 2 for protecting the optical fiber main body 3 and a supporting wire 4 made of a steel wire, a steel stranded wire, an FRP rod or the like for supporting the optical cable main body 3 along the optical cable main body 3 are shown. It is provided.

[0003] In the jacket 2 of the optical cable main body 3, the optical fiber core 1 and the supporting wire 4 are located on a plane including the optical fiber core 1 and on both sides of the optical fiber core 1 at a predetermined interval.
Tensile members (tension members) 5 made of metal such as steel wires are arranged in parallel.
The optical transmission loss is prevented from increasing by suppressing the application of a tensile force exceeding an allowable range. The outer jacket 2 is provided by extruding a resin such as polyethylene or polyvinyl chloride in an oval shape around the optical fiber core wire 1 and the metal tensile strength wire 5. Further, the outer jacket 2 is also provided on the outer periphery of the support line 4 by simultaneously extruding and coating the same resin so as to straddle the outer periphery of the support line 4 so that the optical cable main body 3 and the support line 4 are integrally connected. It has become. Numerals 6 are formed on both outer surfaces of the jacket 2 of the optical cable main body 3 and both outer surfaces of the jacket 2 connecting the optical cable main body 3 and the support wire 4, respectively, and take out the optical fiber core 1 by cable connection or the like. A notch that cuts the outer cover 2 for the purpose.

[0004]

The above-mentioned optical cable is used by being laid and laid from a termination box near a telephone pole located outdoors to the house. When a lightning strike occurs on this cable, the optical cable is installed inside the optical cable main body 3. An electric current flows through the metal tensile strength wire 5 to generate an overcurrent, which easily causes an accident that destroys various devices installed in the house. Recently, in-home equipment has very few cable grounding spaces due to the demand for miniaturization.Therefore, there is a risk that accidents due to lightning strikes will occur frequently and the damage will be greater. I was under pressure.

The present invention has been made in view of the above, and effectively prevents current from entering a house through a cable even if a lightning strike occurs on the cable, suppresses the generation of eddy currents, and reduces equipment in the house. An object of the present invention is to provide a self-supporting optical cable that can prevent breakage.

[0006]

In order to achieve the above object, the present invention has the following arrangement. That is, in a self-supporting optical cable including an optical fiber core wire, an optical cable main body having an outer jacket for protecting the optical fiber core, and a support wire supporting the optical fiber main body along the optical cable main body, the support wire is made of a metal tensile strength. The optical cable body is made of a non-metallic body.

Since the optical cable body of the present invention is made of a non-metallic body as described above, even if a lightning strike occurs on this optical cable, it is possible to effectively block current from entering the house through the cable. In addition, the occurrence of eddy currents can be suppressed and accidents that destroy equipment in the house can be prevented, and damage can be prevented.

Further, since the supporting wire is made of a metal tensile strength member, even if a tensile force is applied to the optical fiber core wire in the optical cable body when laying the cable, most of the tensile force is reduced by the tensile strength. As a result of sharing with a large metal supporting wire, an excessive tensile force exceeding an allowable range is not applied to the optical fiber core wire, and an increase in optical transmission loss can be prevented.

Further, even if the lightning strike occurs and current flows through the metal support line, unlike the optical cable body, the support line can be easily cut, for example, under the eaves of a house. By cutting the support wire once, it is possible to effectively prevent the current from entering the house through the support wire, and it is possible to reliably prevent the equipment in the house from being broken.

[0010]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a first embodiment of a self-supporting optical cable according to the present invention. The self-supporting optical cable according to this embodiment includes a non-metallic optical fiber core wire 11 having about one or two cores (the illustrated example shows two cores) and a non-metallic sheath 12 for protecting the core. Non-metallic optical cable body 13 having the same
And a metal supporting wire 14 made of a steel wire, a steel stranded wire, or the like for supporting the wire.

In the jacket 12 of the optical cable main body 13, a predetermined distance is set between the two sides of the optical fiber core 11 on a plane including the optical fiber core 11 and the support wire 14. A non-metallic tensile wire (tension member) 15 made of a lightweight and high tensile strength material, such as fiber reinforced plastic (FRP), polyester (PET), or polyaramid fiber, is arranged in parallel with the light source. The tensile force applied to the fiber core 11 by laying a cable or the like is reduced so that the optical transmission loss does not increase.

When the tensile strength wire 15 is formed of, for example, a fiber-reinforced plastic material, its Young's modulus (longitudinal elastic modulus) is about 5000 kg / mm ² (4.9 × 10 ⁴ MPa).
Is about 210, which is the Young's modulus when formed of a conventional steel material.
It becomes smaller than 00 kg / mm ² (20.6 × 10 ⁴ MPa). In order to maintain the same tensile strength as that of the conventional cable, the cross-sectional area of the tensile strength wire 15 needs to be approximately four times larger than that of the conventional cable, and the outer diameter of the cable increases accordingly. In the present invention, since the supporting wire 14 is made of a metal having a large tensile strength as described above, a large amount of tensile force is applied to the optical fiber core 11 in the optical cable main body 13 when the cable is laid. Is backed up by the metal supporting wire 14, so that an excessive tensile force exceeding an allowable range is not applied to the optical fiber core, and an increase in optical transmission loss can be prevented.

The nonmetallic jacket 12 is provided by extruding a resin such as polyethylene, polyvinyl chloride or the like into an oval shape around the optical fiber core wire 11 and the nonmetallic tensile wire 15. Further, the outer cover 12 is simultaneously extrusion-coated so that the same resin straddles the outer periphery of the support wire 14 and is also provided on the outer periphery of the support wire 14 so as to have a substantially round shape as a whole. The wires 14 are connected together. Numeral 16 denotes both outer surfaces of the jacket 12 of the optical cable main body 13 and the optical cable main body 13 and the support wire 14.
Are formed on both outer surfaces of the jacket 12 at the portion connecting the optical fiber and the notch (notch) that cuts the jacket 12 to take out the optical fiber 11 by cable connection or the like.

In the self-supporting optical cable of the above embodiment, since the optical cable body 13 is made of a non-metallic body as described above, even if a lightning strike occurs in this optical cable, it is necessary to prevent current from entering the house through the cable. It is possible to effectively cut off, prevent the occurrence of accidents that destroy equipment in the house by suppressing the generation of eddy currents, and eliminate the occurrence of damage.

In addition, when the lightning strike occurs, a metal support wire 1 is formed.
4, unlike the case of the optical cable body 13, the support wire 14 can be easily cut, for example, under the eaves of a house.
By cutting 4 once, it is possible to block the current from entering the house through the support wire 14.
It is possible to reliably prevent equipment in the house from being destroyed. In addition, by cutting the support line 14 once under the eaves, the support line 14 can also be drawn into the house, so that the workability is improved.

FIG. 2 is a cross-sectional view showing a second embodiment of the self-supporting optical cable according to the present invention. The self-supporting optical cable of this embodiment has a single-core (single-core) non-metallic optical fiber core 17 and a non-metallic sheath 12 for protecting the same.
And a non-metallic optical cable main body 18 having the following structure, and the metal supporting wire 14 that supports the optical cable main body 18 along the optical cable main body 18. Then, in the jacket 12 of the optical cable main body 18, a predetermined side is provided on the side opposite to the support wire 14 of the optical fiber core 11 in a plane including the optical fiber core 17 and the support wire 14. The one non-metallic tensile strength wire 15 is arranged in parallel at an interval. Other configurations and functions are the same as those shown in FIG. The self-supporting optical cable having the configuration shown in FIG. 2 has the same effect as the optical cable shown in FIG.

FIG. 3 is a cross-sectional view showing a third embodiment of the self-supporting optical cable according to the present invention. The self-supporting optical cable of this embodiment includes a non-metallic optical cable main body 23 having a non-metallic tape-shaped optical fiber core 19 and a non-metallic jacket 20 for protecting the same. And a supporting line 14 made of metal for supporting it along. And this jacket 20
A non-metallic sheath made of a non-metallic hollow pipe 21 made of fiber reinforced plastic material and having high tensile strength, and a resin such as polyethylene, polyvinyl chloride or the like extruded and coated in an elliptical shape around the hollow pipe 21. There are 22 composite structures. Further, the tape-shaped optical fiber core wire 19 is drawn into the hollow pipe 21 by a lead wire or an air blow through the hollow pipe 21 and stored therein. Further, the sheath 22 of the outer cover 20 is simultaneously provided on the outer periphery of the support wire 14 by simultaneously extruding and covering the resin so as to straddle the outer periphery of the support wire 14, and the optical cable main body 23 and the support wire 14 are integrally connected. It has become so. Other configurations and functions are described in FIG.
And the description is omitted. The self-supporting optical cable having the configuration shown in FIG. 3 has the same effect as the optical cable shown in FIG.

FIG. 4 is a cross-sectional view showing a fourth embodiment of the self-supporting optical cable according to the present invention. The self-supporting optical cable of this embodiment comprises a non-metallic multi-core tape-shaped optical fiber core 24 and a non-metallic sheath 25 for protecting the same.
And a metal supporting wire 14 for supporting the optical cable main body 26 along the optical cable main body 16.

The jacket 25 of the optical cable main body 26
Has an S-type, Z-type or SZ-type helical shape formed on the outer peripheral surface thereof by extrusion-coating a resin such as polyethylene on a nonmetallic tensile wire 15 made of a fiber-reinforced plastic material or the like at the center. A plastic spacer 28 having a circular cross section having a plurality of spiral grooves 27 formed thereon and a non-metal tape holding layer 29 formed by lap winding of a polyester tape or the like on the outer periphery thereof, such as polyethylene, polyvinyl chloride, or the like. It has a composite structure of a non-metallic sheath 30 provided by extrusion coating of a resin. In each spiral groove 27 of the grooved plastic spacer 28, a plurality of optical fiber cores 24 are housed in a stacked state before the tape holding layer 29 is provided on the outer periphery of the spacer 28. . Further, the sheath 30 of the outer cover 25 is simultaneously extruded and covered with the resin so as to straddle the outer periphery of the support wire 14, and is also provided on the outer periphery of the support wire 14, so that the sheath 30 has a substantially barrel shape as a whole. And the support wire 14 are integrally connected. The self-supporting optical cable having the configuration shown in FIG. 4 can provide the same effects as those of the optical cable shown in FIG.

The self-supporting optical cables of the four embodiments are all optical cable bodies 13, 18, 23, 26.
And the support wire 14 are simultaneously extruded and coated with the same resin so as to be substantially in the shape of a whole, and the optical cable body 13 is formed.
And the support wire 14 are integrally connected, but this extrusion coating does not need to be continuously applied in the longitudinal direction of the optical cable main body 13,. It is also possible to form a window in the portion, or to allow the optical cable main body 13,... At the portion of the window to have an extra length, to meander to the side with respect to the axis, and to give a slack. . Also, instead of extruding and covering the optical cable main bodies 13,... And the support wires 14 along the optical cable main bodies with resin, and connecting them integrally, a bind wire (not shown) is spirally wound around them. Both may be connected, and the connecting means of both is not limited only to one-shot extrusion coating. Further, in the embodiments shown in FIGS. 1, 2 and 4, the non-metallic tensile wire 15 is provided. However, when the optical cable main body does not receive a large tension due to the laying conditions and the use state of the optical cable. Since the tension can be sufficiently borne by the metal supporting wire 14, the use of the tensile strength wire 15 can be eliminated.

[0021]

As described above, according to the present invention,
In a self-supporting type optical cable including an optical fiber core wire, an optical cable main body having an outer jacket for protecting the optical fiber core, and a support wire supporting the optical fiber main body along the optical cable main body, the support wire is made of a metal tensile member. Since the optical cable body is made of a non-metallic body, even if a lightning strike occurs on this optical cable, it is possible to effectively block the current from entering the house through the cable, and suppress the occurrence of eddy currents. An accident that destroys equipment in the house can be prevented from occurring, and damage can be prevented.

Further, since the supporting wire is made of a metal tensile strength member, even if a tensile force is applied to the optical fiber core wire in the optical cable body when laying the cable, most of the tensile force is reduced by the tensile strength. As a result of being shared by the large metal supporting wire, an excessive tensile force exceeding an allowable range is not applied to the optical fiber core wire, and an increase in optical transmission loss can be prevented.

Furthermore, unlike the case of the optical cable main body, the support line can be easily cut under the eaves of a house, for example, even if the lightning strike causes a current to flow through the metal support line. By cutting the support wire once, it is possible to block the current from entering the house through the support wire, and it is possible to reliably prevent the equipment in the house from being broken.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a self-supporting optical cable according to the present invention.

FIG. 2 is a cross-sectional view showing a second embodiment of the self-supporting optical cable according to the present invention.

FIG. 3 is a cross-sectional view showing a third embodiment of the self-supporting optical cable according to the present invention.

FIG. 4 is a cross-sectional view showing a fourth embodiment of the self-supporting optical cable according to the present invention.

FIG. 5 is a cross-sectional view showing a conventional self-supporting optical cable.

[Explanation of symbols]

 11, 17, 19, 24 Optical fiber core wire 12, 20, 25 Jacket 13, 18, 23, 26 Optical cable body 14 Support wire 15 Tensile wire 16 Notch 21 Hollow pipe 22, 30 Sheath 27 Spiral groove 28 With groove Plastic spacer 29 Tape holding winding layer

Claims (1)

[Claims] 1. A self-supporting type optical cable comprising: an optical cable main body having an optical fiber core wire, an outer sheath for protecting the optical fiber core, and a support line for supporting the optical fiber main body along the optical cable main body. A self-supporting optical cable, wherein the optical cable body is made of a non-metallic body, and is made of a tensile strength member made of stainless steel.