JPH1010384A - Optical cable for subscriber - Google Patents

Abstract

(57) [Problem] To provide an optical cable to be connected to a subscriber such as a general home, which is easy to handle and can be manufactured at low cost. SOLUTION: A tension member 1 and an optical fiber core 2 are provided.
Are arranged in parallel with each other, and the connecting portion between the covering portion on the tension member and the covering portion on the optical fiber core is made of a plastic covering comprising a neck portion 5 and the like. Has a narrowed portion, and has a tear cord 3 embedded in the plastic coating near the optical fiber core 2 and on the side opposite to the side where the tension member is provided, parallel to the optical fiber core wire. ing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical cable connected to a subscriber such as a general home, and an object of the present invention is to provide an optical cable which can be easily handled and manufactured at low cost.

[0002]

2. Description of the Related Art At present, studies are underway to connect an optical fiber communication network to ordinary households.
Each home needs to have at least one optical fiber core. In order to provide such a purpose, a cable having a structure as shown in FIG. 5 has been studied as a subscriber optical cable. (See, for example, JP-A-8-75
In FIG. 5, reference numeral 51 denotes a tension member, 52 denotes an optical fiber core obtained by coating a glass fiber with a plastic, 53 denotes an outer coating made of vinyl chloride or the like, and 54 denotes a cut.

As another example, there is one having a structure shown in FIG. In FIG. 6, the tension member 60 with a cover is provided.
Is a plastic coating 6 such as vinyl chloride on the steel wire 61.
In the optical fiber main body portion 70, the coated optical fiber core wires 63 are arranged in two cores in parallel, a steel wire 64 thinner than the tension member is arranged on both sides thereof, and a spectacle type so as to cover them. And a plastic such as vinyl chloride. The central optical fiber core portion has cuts 66 from both sides so that the optical fiber core is exposed when the cut is cut off. The optical fiber main body 70 is twisted and wound around the coated tension member 60.

[0004]

In the case of such an optical cable for a subscriber, in the example of FIG.
The optical fiber core 52 is separated from the optical fiber core 52 by a knife or the like with the tension member and the optical fiber core coated, respectively, in accordance with the cut 54 at the cable end.
Separate, grasp each with your finger and pull
A predetermined length of separation can be achieved. However, in order to extract the optical fiber core, it is necessary to remove the vinyl chloride coating on the optical fiber core again using a coating remover or the like. In this case, when the removal of the vinyl chloride coating is short, the PVC coating can be removed with a simple tool, but when the length of the vinyl chloride coating removal is as long as 30 to 40 cm, the removal is not easy. .

In the example shown in FIG. 6, the coated tension member 60 and the optical fiber main body 70 are manufactured in separate steps, and the optical fiber main body is wound on the coated tension member. There is a problem that the manufacturing processing cost is high. In contrast to such a conventional technology, the present invention provides a subscriber optical cable having a tension member and an optical fiber, which can be manufactured at a low cost and facilitates taking out of the optical fiber. is there.

[0006]

That is, in the cable according to the present invention, the tension member and the optical fiber are arranged in parallel, and the optical fiber for the subscriber is integrally covered with plastic. The plastic coating of the connecting portion between the coated portion of the optical fiber and the coated portion on the optical fiber has a narrowed portion, and the plastic coated near the optical fiber and opposite to the side where the tension member is located. A tear string is embedded therein in parallel with the optical fiber core.

[0007] The portion where the width of the plastic coating at the connecting portion between the coating portion on the tension member and the coating portion on the optical fiber core is narrow may be a neck portion having a fixed width or from both sides. It may be a notch.
In addition, if a steel wire thinner than the tension member is embedded in the tension member side in the coating of the optical fiber core wire in parallel with the optical fiber core wire, when the tear cord is pulled to make a cut in the coating, the steel wire is used. Shares the tensile force of the other side, so that a large tensile force is not applied to the optical fiber core, and the optical fiber core is less likely to be damaged.

Further, if a cut is made from the outside in the covering of the portion in which the tear string is embedded, the covering portion can be more easily torn by the tear string, and the removal of the optical fiber core becomes easier. As the optical fiber core, a single-core glass fiber coated with a silicone resin, a nylon resin, or the like is often used. Those can also be used as optical fiber cores.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. In the figure, reference numeral 1 denotes a tension member made of a steel wire or the like, and 2 denotes an optical fiber core obtained by coating a glass fiber with a UV resin, a nylon resin, or the like. Reference numeral 3 denotes a high-strength fiber string such as a polyester string, a nylon string, and a Kevlar, a tear string formed of a steel wire or the like, and 4 denotes a coating made of a plastic such as vinyl chloride. The plastic coating of the connecting portion between the coating on the tension member and the coating on the optical fiber core has a narrow portion, but has a narrow width like a neck portion 5 having a constant width, or both sides. There is a shape in which the width is narrowed by the notch 6. Reference numeral 7 denotes a steel wire thinner than the tension member disposed in parallel with the optical fiber core.

Although the tear string 3 is arranged along the optical fiber 2, the tear string and the optical fiber do not necessarily have to be in contact with each other, and a material of a single integral coating enters between them. May be.

[0011]

EXAMPLE A 1.2 mm diameter plated steel wire was used as a tension member, and a single cored 0.9 mm nylon resin coated outer diameter was used as the optical fiber core, and was integrally formed with vinyl chloride. 1,2,
Three or four subscriber optical cables were prototyped. The dimensions of the integral coating were such that the outer diameter of the tension member portion was 3 mm and the outer diameter of the optical fiber core portion was 2 mm (3 mm in FIG. 4). In addition, a stretched polyester cord having a diameter of 0.25 mm was used as the tear cord, and was arranged along the optical fiber core. In addition, the width dimension of the part where the width of the connecting portion between the tension member coating and the optical fiber core coating was reduced was 0.5 mm in each of FIGS. Further, a 0.7 mm steel wire was used as the steel wire 7 in FIG.

Using a subscriber optical cable prototyped in the above-described structure, a notch is cut with a knife at the end of the portion where the width of the connecting portion between the tension member covering portion and the optical fiber core covering portion is reduced. The tension member portion and the optical fiber core portion were separated by a length of about 3 cm enough to be grasped with a finger, and each was pulled with a finger. As a result, separation was easily performed over a length of about 30 cm. Also, when the tear string was embedded in the portion where the tear string was embedded at the end, the tear string was taken out with a knife, and the tear string was pulled with a finger. Was made, and the optical fiber core was easily taken out from that part.

[0013]

In the optical fiber cable for a subscriber according to the present invention, a narrow portion is provided by a neck portion or a notch at a connecting portion between the covering portion on the tension member and the covering portion on the optical fiber core. By simply making a notch long enough to be grasped by a finger or the like with a knife or the like, a long separating portion can be obtained by simply pulling and pulling the tension member portion and the optical fiber core portion with a finger. In addition, since the tear string is arranged near the optical fiber core portion, it is possible to take out the tear string enough to be grasped with a knife or the like at the end of the cable and provide a tear portion in the covering of the portion only by pulling with a finger. The optical fiber cable can be easily removed therefrom. In addition, if the optical fiber and the tearing cord are brought into contact with each other and embedded in the coating, when the coating is cut off with the tearing string, a part of the optical fiber is exposed and the optical fiber is easily taken out. become.

When the cable is wound around a drum at the time of manufacturing a cable or the like, the cable is bent along the plane formed by the center line of the tension member and the center line of the optical fiber core, and the cable is bent around the tension member and the optical fiber core. Bends in a direction where no pulling or compressing force acts,
Since the position of the tear string is opposite to the side where the tension member is located, the tear string is also in the same plane of the bending, and no pulling or compressive force is applied to the tear string. The compression of the line does not deteriorate the transmission characteristics.

In some cases, it is necessary to take out the optical fiber core without separating the tension member portion and the optical fiber core portion. In this case, since the tear string is located on the opposite side of the position where the tension member is located, By pulling the tension member and the tear string to the opposite side, respectively, the work of tearing the coating with the tear string can be performed, so that a large force is not applied to the optical fiber core,
There is less risk of damaging the optical fiber.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a subscriber optical cable according to the present invention.

FIG. 2 is a diagram showing another embodiment of the optical fiber cable for a subscriber according to the present invention.

FIG. 3 is a diagram showing another embodiment of the optical fiber cable for a subscriber of the present invention.

FIG. 4 is a view showing another embodiment of the optical fiber cable for a subscriber of the present invention.

FIG. 5 is a diagram showing an example of a conventional optical fiber cable for a subscriber.

FIG. 6 is a diagram showing another example of a subscriber optical cable according to the related art.

[Explanation of symbols]

 1: tension member 2: optical fiber core 3: tear cord 4: covering 5: neck 6: cut 7: steel wire

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigeru Tanaka 1-chome, Taya-cho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Sumitomo Electric Industries, Ltd. Yokohama Works (72) Inventor Kazuo Hokari 3-9-1, Nishishinjuku, Shinjuku-ku, Tokyo No. Nippon Telegraph and Telephone Corporation (72) Inventor Shinichi Furukawa 3-19-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Nippon Telegraph and Telephone Corporation

Claims (7)

[Claims] In a subscriber optical cable in which a tension member and an optical fiber are arranged in parallel and integrally covered with plastic, a coated portion on the tension member and a coated portion on the optical fiber are provided. In the connecting part of the plastic coating has a narrower part,
An optical cable for a subscriber, wherein a tear string is embedded in a plastic coating near the optical fiber core and opposite to the side where the tension member is located, in parallel with the optical fiber core. 2. The narrow portion of the plastic covering of the covering portion on the tension member, the covering portion on the optical fiber cable, and the connecting portion is formed of a neck portion having a constant width. 2. The optical cable for subscribers according to 1. 3. The portion where the width of the plastic coating of the connecting portion between the coating on the tension member and the coating on the optical fiber core is reduced is formed by cutting from both sides. Item 1. An optical cable for a subscriber according to Item 1. 4. In a subscriber optical cable in which a tension member and an optical fiber are arranged in parallel and integrally coated with plastic, a coated part on the tension member and a coated part on the optical fiber are provided. The plastic covering of the connecting part has a narrowed portion, and is torn in parallel with the optical fiber in the plastic covering near the optical fiber and opposite to the side where the tension member is located. And a steel wire thinner than the tension member in parallel with the optical fiber core is embedded on the tension member side in the optical fiber core coating. 5. The optical fiber cable for a subscriber according to claim 1, wherein a cutout is provided from the outside at a portion where the tear string is embedded in a coating portion on the optical fiber core wire. 6. The optical cable for a subscriber according to claim 1, wherein the optical fiber core wire and the tear string are in contact with each other. 7. The optical fiber cable for a subscriber according to claim 1, wherein the optical fiber has a single-core or multi-core optical fiber.