JP2003090943A - Optical fiber cable and method for drawing and anchoring the optical fiber cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the need to guide the support wire of a self-support type optical fiber cable, to easily draw and anchor it, and to make the radius of minimum bending small. SOLUTION: The optical cable fiber 1 comprises an optical element part 7 having a coated optical fiber 5 embedded in a sheath 3 and a cable support wire part 11 which is fixed in parallel to the optical element part 7. The cable support wire part 11 comprises the support wire 19 constituted by stranding a tensile strength body 17 made of a gathering body of nonconductive tensile strength fiber with a core material 15 made of a resin-based material and a sheath 21 covering the support wire 19. Consequently, the self-support type optical fiber cable 1 need not be guided and has a small radius of minimum bending.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber cable and a method for retaining the optical fiber cable, in which the supporting wire of a self-supporting optical fiber cable is made non-inductive and the flexibility of the supporting wire is improved.

[0002]

2. Description of the Related Art Conventionally, FTTH (Fiber to the Home)
That is, in order to be able to send and receive high-speed broadband information such as ultra-high-speed data at home or office, the optical fiber cable extended from the central office is dropped into the subscriber's home such as a general residence. A fiber optic drop cable suitable for wiring this is used. That is, the optical fiber drop cable (outdoor line) is a cable used when the optical fiber is pulled into the home from the pole.

An optical fiber drop cable of this type is disclosed in Japanese Patent Laid-Open No. 2001-83385.
That is, the structure of the optical fiber drop cable 101 is, as shown in FIG. 4, a pair of conductive metal wires, for example, a tensile strength member 105 made of steel wire on both sides of the optical fiber core wire 103 or the optical fiber tape core wire. Is attached. These are collectively a cable sheath 1 of thermoplastic resin.
Optical element portion 109 covered with 07 and a cable support wire portion 115 in which a support wire 111 made of a metal wire such as a steel wire is covered with a thermoplastic resin sheath 113.
And are integrally connected to each other via a neck portion 117 which is parallel to each other and is constricted.

Referring also to FIG. 5, when the optical fiber core wire 103 is pulled down from the optical fiber cable 119 extended from the telephone office to each home, the above optical fiber drop cable 101 is used. The optical element portion 109 and the cable support wire portion 115 are separated by partially tearing off the neck portions 117 at both end portions of the cable 101, and the separated one cable support wire portion 115.
115A of the outside of the telephone pole 121 of the telephone pole 121
, And the other end 115B is fixed to a part of the house through a retainer 123.

Further, one end 109A of the optical element portion 109 is provided with a cable branch box 125 on the electric pole 121.
(Cable closure), the other end 109
B is connected to an indoor OE converter or termination box 127.

[0006]

In the above optical fiber drop cable 101, the steel wire stranded wire or FRP is used for the supporting wire 111 of the cable supporting wire portion 115 in addition to the above-mentioned steel wire. Cable 101 using wire or steel wire
However, since it is a conductive metal wire, there is a problem in that it is guided during a lightning strike or guided from a power cable.

In addition, it is difficult to hold the cable 101 using the FRP for non-induction.
Since the minimum bending radius is large, there is a problem that the workability of laying is poor.

The present invention has been made in order to solve the above-mentioned problems, and an object thereof is to de-guide the support wire of a self-supporting optical fiber cable and easily hold it, and to reduce the minimum bending radius. (EN) A possible optical fiber cable and a method for retaining the optical fiber cable.

[0009]

In order to achieve the above object, an optical fiber cable of the present invention according to claim 1 has an optical element portion in which an optical fiber core wire is embedded in a sheath, and an optical element portion in the optical element portion. In an optical fiber cable composed of a cable supporting wire portion fixed in parallel, the cable supporting wire portion is formed by twisting a strength member made of an aggregate of non-conductive strength fibers on a core material made of a resin material. The present invention is characterized in that it is composed of a support wire that is configured together and a sheath that covers the support wire.

Accordingly, since the supporting wire is formed by twisting the strength member made of the non-conductive strength fiber group on the core material made of the resin material, the self-supporting optical fiber cable is non-inductive and has a small minimum bending radius. , Induction of lightning strikes and induction from power cables are avoided, and laying workability is improved.

The optical fiber cable of the present invention according to claim 2 is the optical fiber cable according to claim 1,
The strength member is made of aramid fiber or glass yarn.

Therefore, when a wedge-shaped gripping tool is used to grip the cable supporting wire portion, it is easily gripped by deforming the tensile strength member in the portion where the aramid fiber, glass yarn and the like are twisted together.

The optical fiber cable of the present invention according to claim 3 is the optical fiber cable according to claim 1,
The diameter of the core material is 0.2 times or more and 0.7 times or less the inner diameter of the sheath, and the outer diameter of the sheath is 1.2 times or more and 2.0 times or less the inner diameter of the sheath. It is characterized by becoming.

Therefore, when the ratio of the diameter of the core material of the cable supporting wire portion to the inside diameter and the outside diameter of the sheath is within the above range, the gripping force of the gripping tool becomes optimum.

According to a fourth aspect of the present invention, there is provided an optical fiber cable retaining method, wherein an optical element portion having an optical fiber core wire embedded in a sheath and a cable supporting wire portion fixed in parallel to the optical element portion. When holding the optical fiber cable composed of and using a gripping tool, the cable supporting wire portion is twisted with a strength member made of an aggregate of non-conductive strength fibers and a core material made of a resin material. It is characterized in that the outer periphery of the strength member is covered with a sheath, and the cable supporting wire portion is deformed and held by a wedge-shaped gripping tool.

Therefore, when a wedge-shaped gripping tool is used to grip the cable supporting wire portion, it is easily gripped by deforming the tensile strength member of the portion where the Kevlar, the glass yarn and the like are twisted together.

The optical fiber cable retaining method according to a fifth aspect of the present invention is the optical fiber cable retaining method according to the fourth aspect, wherein the diameter of the core is 0.2 times or more the inner diameter of the sheath and 0.7. The outer diameter of the sheath is 1.2 times or more and 2.0 times or less of the inner diameter of the sheath.

Therefore, the operation is the same as that of claim 3, and when the ratio of the diameter of the core material of the cable supporting wire portion to the inner diameter and the outer diameter of the sheath is within the above range, the gripping force of the gripping tool is optimal. It becomes something.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

Referring to FIGS. 1 and 2, as an optical fiber cable according to this embodiment, for example, an optical fiber drop cable 1 has a sheath 3 in which an optical fiber single core wire or an optical fiber tape core wire (hereinafter referred to as Collectively referred to as an optical fiber core wire 5) and a long optical element portion 7 embedded therein, and a neck portion 9 constricted in parallel with the optical element portion 7 for continuous or intermittent fixation. The long cable support wire portion 11 is formed.

The optical element portion 7 sandwiches the optical fiber core wire 5 and has at least a pair of long tensile strength members 13 on both sides thereof.
Are arranged in parallel, and these are covered with a cable sheath 3 made of a thermoplastic resin such as polyethylene or polyvinyl chloride (PVC) to form a long optical element portion 7.

The tensile strength member 13 is a non-conductive tensile strength fiber having high tensile strength, for example, aramid fiber such as Kevlar (trademark), or polymer fiber such as PBO fiber spun with polyparaphenylenebenzobisoxazole (PBO). ,
Fibers made of glass fibers, other aramid fibers, PBO fibers, or composite materials in which glass fibers and a synthetic resin are used as a matrix are assembled.

The long cable supporting wire portion 11 is integrally connected to and attached to the long optical element portion 7 via a neck portion 9 constricted in parallel.

The cable supporting wire portion 11 is made of FRP.
A support wire 19 formed by twisting a strength member 17 made of an aggregate of non-conductive strength fibers to a core material 15 made of a resin material such as (glass fiber reinforced plastic) or engineering plastic (engineering plastic), and a support wire 19 for supporting the strength. It is composed of a sheath 21 covering the wire 19.

The tensile strength member 17 is made of, for example, Kevlar (trademark) or glass yarn. A sheath 21 is coated on the outer periphery of the strength member 17 with a thermoplastic resin such as polyethylene or polyvinyl chloride (PVC).

It should be noted that a common thermoplastic resin may be collectively extruded and coated as the cable sheaths 3 and 21 of the optical element portion 7 and the cable support wire portion 11 so that they are integrally fixed. That is, when the optical fiber core wire 5 and the tensile strength body 13 are covered with the cable sheath 3, the support wire 19 may be covered with the sheath 21 at the same time in the mold. In this case, the cable sheath 3 of the optical element portion 7 and the sheath 21 of the cable support wire portion 11 are common sheaths. The support wire 19 may be coated with the sheath 21 in advance.

When the above optical fiber drop cable 1 is laid, the cable branch connection box (closure) attached to the end of the aerial optical fiber cable on the telephone pole extended from the telephone station and the subscriber's house The above-mentioned optical fiber drop cable 1 is wired in between, and the optical fiber is dropped from the overhead optical fiber cable into the home. Since this method is almost the same as that shown in the conventional description, detailed description thereof will be omitted, and different points will be described below.

As an outdoor detaining tool for gripping the cable support wire portion 11 of the optical fiber drop cable 1, as shown in FIG. 3, for example, a taper 23 having a conical shape is used.
A wedge-shaped grasping tool 27 having a slidable wedge-shaped wedge member 25 therein is used, and the tensile strength body 17 of the cable support wire portion 11 is deformed to obtain a grasping force. At this time, the core material 15 of the cable support wire portion 11
The ratio of the diameter of the grip 21 to the inner diameter and the outer diameter of the sheath 21 is set within the following range, so that the gripping force of the gripping tool 27 is optimized.

Referring to FIG. 2, the cable support wire portion 11
The diameter of the core material 15 is a, the inner diameter of the sheath 21 is b,
When the outer diameter of the sheath 21 is c, 0.2b ≦ a ≦ 0.7
By setting the range to b and the range to 1.2b ≦ c ≦ 2.0b, the grasping tool 27 can easily grasp the cable support wire portion 11.

More specifically, the above 0.2b ≦ a ≦ 0.
In the range of 7b, the grip is performed by the repulsive force against the deformation of the tensile strength body 17 between the core material 15 and the sheath 21. When the core material 15 is thinner than the above range, the grip is not stable, and when the core material 15 is thicker than the above range, the gripping force is weak.

Since the above range of 1.2b ≦ c ≦ 2.0b is converted into 0.2b ≦ (c−b) ≦ 1.0b, the sheath thickness (= c−b) is equal to the inner diameter of the sheath. 0.2 times to 1.0 times. When the sheath thickness is smaller than the above range, the sheath 21 is cut and the gripping portion is displaced. On the contrary, when the sheath thickness is larger than the above range, the deformation amount of the sheath 21 is small and the gripping force is small. Get smaller.

Examples will be shown below.

(Embodiment) In the optical fiber drop cable 1 shown in FIGS. 1 and 2, the core material 15 of the support wire 19 is 0.
4 mm (= a) glass FRP, the strength member 17 is Kevlar, and various cables are used as shown in Table 1 below with the inner diameter (= b) and outer diameter (= c) of the sheath 21 as parameters. I made a prototype.

That is, in Table 1, the diameter a of the core material is 0.4.
mm and the sheath inner diameter b is 0.5 mm, 0.57 mm,
The sheath outer diameter c is 0.60 mm, 0.68 mm, 0.96 mm for 0.8 mm, 2.0 mm, and 2.2 mm, respectively.
1.14mm, 1.60mm, 2.40mm, 2.65mm,
Various cables for 4.00 mm, 4.40 mm, and 5.00 mm were made as prototypes.

The inner diameter of the sheath 21 is adjusted by the amount of Kepler.

[0036]

[Table 1] A grip evaluation was made for each cable in Table 1 above,
The results are shown in Table 2. As an evaluation method of gripping in Table 2, a tensile test between the gripping tool 27 and the support wire 19 is performed, and when the deviation of the gripping tool 27 occurs before the breakage of the support wire 19, the gripping tool is indicated by x. When the support line 19 breaks before the deviation of 27, it is indicated by a circle.

[0037]

[Table 2] From Table 2 above, the range of 0.2b ≦ a ≦ 0.7b and the range of 1.2b ≦ c ≦ 2.0b make it easy to hold the cable support wire portion 11 by the holding tool 27. It turns out that

As described above, in the self-supporting optical fiber cable, the core material 15 such as FRP or engineering plastic having a small diameter is used.
By using, as the support wire 19, a material obtained by twisting a tensile strength member 17 such as Kevlar or glass yarn is used.
Since it is a self-supporting optical fiber cable that is non-inductive and has a small minimum bending radius, it is possible to avoid induction at the time of lightning strike and induction from the power cable, and improve the laying workability.

Further, in the self-supporting optical fiber cable of the present invention, the wedge-shaped grasping tool 27 is used, so that the tensile strength body 17 in the portion where the Kevlar, the glass yarn, etc. are twisted together is deformed and easily grasped. It becomes possible.

The present invention is not limited to the above-described embodiment, but can be implemented in other modes by making appropriate changes.

In the above-mentioned embodiment, the optical element portion is an optical fiber drop cable, but it may be, for example, a slot cable, a yarn tube cable, an LT cable, a unitube cable, a loose tube cable, or any other cable. I do not care.

[0042]

As can be understood from the above description of the embodiments of the present invention, according to the invention of claim 1, the support wire is a core material made of a resin-based material, and a non-conductive tensile fiber group is attached to the core material. Since the strength members composed of the body are twisted together, it is possible to obtain a self-supporting optical fiber cable which is non-inductive and has a small minimum bending radius.

According to the second aspect of the invention, by using the wedge-shaped gripping tool for gripping the cable supporting wire portion, the tensile strength body k of the portion where the aramid fiber, the glass yarn and the like are twisted is deformed. Can be easily grasped.

According to the third aspect of the invention, the gripping force of the gripping tool can be optimized by setting the ratio of the diameter of the core material of the cable supporting wire portion to the inner diameter and outer diameter of the sheath within a predetermined range. .

According to the invention of claim 4, by using the wedge-shaped gripping tool for gripping the cable supporting wire portion, it is easy to deform the tensile strength member in the portion where the aramid fiber, the glass yarn and the like are twisted together. Can be gripped.

According to the invention of claim 5, which has the same effect as that of claim 3, gripping is performed by setting the ratio of the diameter of the core material of the cable support wire portion to the inner diameter and outer diameter of the sheath within a predetermined range. The gripping force of the tool can be optimized.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention and is a schematic cross-sectional view of an optical fiber drop cable.

FIG. 2 is an enlarged cross-sectional view of the cable support wire portion of FIG.

FIG. 3 is a cross-sectional view of a state in which the cable support wire portion of FIG. 1 is held by a gripping tool.

FIG. 4 is a schematic sectional view of a conventional optical fiber drop cable.

FIG. 5 is an explanatory diagram showing a state of implementation of a conventional cable.

[Explanation of symbols]

1 Optical fiber drop cable (optical fiber cable) 3 Sheath (of optical element portion 7) 5 Optical fiber core wire 7 Optical element portion 9 Neck portion 11 Cable support wire portion 13 Strength member (of optical element portion 7) 15 Core material 17 Strength Body (of cable support wire portion 11) 19 Support wire 21 Sheath (of cable support wire portion 11) 23 Taper 25 Wedge member 27 Grasping tool (outdoor wire pulling and holding tool)

Continued front page    (72) Inventor Kazunaga Kobayashi             1440 Rokuzaki, Sakura City, Chiba Prefecture Fujikura Ltd.             Sakura office (72) Inventor Suehiro Miyamoto             1440 Rokuzaki, Sakura City, Chiba Prefecture Fujikura Ltd.             Sakura office F term (reference) 2H001 BB15 BB19 BB27 DD06 HH02

Claims (5)

[Claims] 1. An optical fiber cable comprising an optical element portion in which an optical fiber core wire is embedded in a sheath, and a cable support wire portion fixed in parallel to the optical element portion, wherein the cable support is provided. The wire portion is composed of a support wire composed of a core material made of a resin material and a strength member made of an assembly of non-conductive strength fibers twisted together, and a sheath covering the support wire. Optical fiber cable characterized by. 2. The optical fiber cable according to claim 1, wherein the strength member is made of aramid fiber or glass yarn. 3. The diameter of the core material is configured to be 0.2 times or more and 0.7 times or less the inner diameter of the sheath, and the outer diameter of the sheath is 1.2 times or more and 2.0 times the inner diameter of the sheath. The optical fiber cable according to claim 1, which is configured as follows. 4. An optical fiber cable comprising an optical element portion in which an optical fiber core wire is embedded in a sheath and a cable supporting wire portion fixed in parallel to the optical element portion using a gripping tool. At the time of retaining, the cable supporting wire portion is formed by twisting a strength member made of an aggregate of non-conductive strength fibers to a core made of a resin-based material, and covering the outer circumference of the strength member with a sheath. A method for retaining an optical fiber cable, characterized in that the cable supporting wire portion is retained by deforming the strength member with a wedge-shaped grasping tool. 5. The diameter of the core material is 0.2 times or more and 0.7 times or less the inner diameter of the sheath, and the outer diameter of the sheath is 1.2 times or more and 2.0 times or less the inner diameter of the sheath. The method for retaining an optical fiber cable according to claim 4, wherein