JP2572640B2 - Optical fiber cable and method of forming terminal portion thereof - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber cable used for wiring of office automation equipment and the like, a method of forming a terminal portion thereof, and a protective tube used in the method.

[Conventional technology and its problems]

The optical fiber cables include a layered optical fiber cable and a cord-assembled cable.

In the former, as shown in FIG. 3, an optical fiber core wire 2 is twisted around the outer periphery of the tension member 1, and a presser-wound tape 4 is wound around the outer periphery of the tension member 1 via a yarn 3, and then polyvinyl chloride (PVC). ), Polyethylene (PE) or the like, and a cable jacket 5 is provided. In some cases, the tension member jacket 1a is not provided.

This cable has a small (thin) outer diameter and is advantageous when laid in free access or floor ducts, etc.
The allowable bending radius is also small. However, in a terminal portion which is a connection portion with the device, the cable jacket 5 is peeled off to expose and connect the optical fiber core wire 2. The optical fiber core 2 is
It is susceptible to tension, bending, torsion and the like, and is easily damaged. Therefore, special care is required at the time of wiring, resulting in a decrease in work efficiency.

On the other hand, in the latter, as shown in FIG. 6, an optical fiber cord 8 in which an optical fiber core 2 is coated with PVC 7 through a high tensile strength fiber 6 around a jacket 1a of a tension member 1 is made of polypropylene (PP). It is arranged with a yarn 9 interposed therebetween, wound around a holding tape 10 and then covered with a PVC jacket 11.

In this cable, the optical fiber cord 8 is exposed at the terminal portion, but the optical fiber cord 8 is rich in tension resistance, bending resistance, and torsion resistance, so that it is damaged like the former. There is no reduction in work efficiency during wiring due to easiness. However, since the cable outer diameter is large (thick), it is disadvantageous when laid in a free access or a floor duct as compared with the former. In addition, since it is thick, the allowable bending radius naturally becomes large.
Therefore, a lot of space is required for wiring, which leads to a reduction in wiring work efficiency.

The present invention has been made in view of the above points, and an object of the present invention is to make the terminal portion of the former optical fiber cable excellent in tensile strength, bending resistance, torsion resistance, etc., that is, excellent in mechanical properties. And

[Means for solving the problem]

To achieve the above object, according to the present invention, first, a protective tube is formed by providing a plastic sheath around the outer periphery of a cylindrical high tensile strength fiber layer. A required length of the cable jacket is stripped from the end surface of the optical fiber cable in which the fiber cores are twisted, and the protective tube is inserted through the entire length of the exposed optical fiber core, and the insertion end of the protective tube is The plastic sheath is peeled off, and the exposed high tensile strength fiber is fixed to the cable jacket, the tension member or both so as to cover the outer periphery thereof, and the outer periphery of the cable jacket end and the plastic sheath of the protective tube are provided. The configuration was such that a protective layer was provided on both sides of the outer periphery.

The end portion of the optical fiber cable thus configured is such that the protective tube covers the optical fiber core wire from which the cable jacket is stripped, and the high tensile strength fiber is fixed to the cable jacket and the tension member. Therefore, the mechanical strength is excellent, and the handling is also improved.

At the end of the optical fiber cable, an optical fiber core wire with a protective tube is wound around the outer periphery of the tension member at an appropriate pitch, and an insulating tape is wound and fixed at a required lengthwise interval. The length may be different for each or a plurality of the optical fibers, and a connector may be attached to a tip of each of the optical fibers.

The end portion of the optical fiber cable configured as described above has a protective optical fiber core wire wound at an appropriate pitch.Therefore, when a cable is laid, a stress applied to the optical fiber when bending is applied is reduced. small. In addition, since the length of each optical fiber core wire with a protective tube is different for each or a plurality thereof, a large number of connectors are not located at the same position on the cable axis, so that the mounting portions of the connectors overlap. There is no possibility that the layers cannot be arranged in layers, and there is no possibility that a failure may occur due to bending.

Further, the method of the present invention for forming the above-mentioned optical fiber cable comprises the steps of stripping a required length of a cable jacket of an optical fiber cable in which optical fibers are twisted like the above-mentioned layered optical fiber cable, and tension members and optical fibers. Along with exposing the fiber core, the plastic sheath of the protective tube is stripped off for a required length, and the protective tube is inserted through the stripped end of the plastic sheath through the entire exposed optical fiber core, thereby exposing the exposed high tensile strength. The fiber is covered on the outer circumference of the cable jacket, the tension member or both, and fixed with an adhesive, so that the outer circumference of the cable jacket end and the outer circumference of the protective tube plastic sheath are both covered.
The protective layer was provided by covering the heat-shrinkable tube and shrinking by heating, or by winding an insulating tape.

With this configuration, the optical fiber cable of the present invention can be obtained.

Further, the optical fiber core wire with the protective tube of the optical fiber cable is cut so that the length is different for each or a plurality of wires, and after attaching a connector to each of the cut ends, tension is applied at an appropriate pitch. It can be wound around the outer periphery of the member, and the insulating tape can be wound and fixed at a required portion in the length direction of the wound optical fiber.

With this configuration, it is possible to obtain a terminal portion of the optical fiber cable of the present invention.

In addition, the above-mentioned protective tube may be formed by sequentially providing a cylindrical high tensile strength fiber layer and a plastic sheath on a plastic tube. In this case, since the inner surface of the protective tube is smooth, the work of inserting the exposed optical fiber into the core becomes easy. When inserting this protective tube into the optical fiber, strip the plastic sheath for the required length, insert the plastic tube into the optical fiber, and bring the end of the plastic tube to the stripped end surface of the cable.
Thereafter, a terminal portion is formed in the same manner as described above.

〔Example〕

First, as shown in FIG. 3 described above, the cable main body 20 is formed by twisting the optical fiber core wire 2 around the outer circumference of the jacket 1a of the tension member 1 and holding the outer circumference thereof through the yarn 3 as shown in FIG. After the winding tape 4 is wound, a cable jacket 5 is provided by coating with PVC.

As shown in FIG. 2, at a terminal portion serving as a connection portion of the cable main body 20 to the device, the jacket 5 and the presser winding tape 4 are removed (removed) by a required length, for example, about 2 m.

On the other hand, as shown in the figure, as shown in Table 2, 12 protective tubes 23 provided with a plastic sheath 22 on the outer periphery of the cylindrical high tensile strength fiber layer 21 are prepared, and the plastic sheath 22 at one end is required length. For example, remove about 5 cm (peel off).

Next, as shown in FIG. 1, the protection tube 23 is peeled off, and the exposed optical fiber core wire 2 is inserted from the stripped end side.
The high-strength fiber 21 of the protective tube 23 is put on the outer periphery of the cable jacket 5 by reaching the stripped end surface of the cable jacket 5. After the high tensile strength fiber 21 of each protective tube 23 covering the cable jacket 5 is bound by a binding material 24, the cable is fixed to the cable jacket 5, the tension member 1 or both 5, 1 by an adhesive 25, and Wrap the vinyl chloride tape 27
To temporarily prevent the adhesive portion 25 from sagging. Subsequently, a heat-shrinkable tube is slid over the protection tube 23 to cover the fixed portion, and the heat-shrinkable tube is shrunk to provide the protection layer 26, thereby completing the formation of the terminal portion. The protective layer 26 can be formed by molding with an epoxy resin or the like, or can be formed by winding an insulating tape.

The cable end portion thus configured has the optical fiber core 2 covered with the protective tube 23, that is, is optically coded, and the high tensile strength fiber 21 is covered with the cable jacket 5, the tension member 1 and the like. , It has high mechanical strength, and as shown in FIG.
Each optical fiber core 2 is cut to an appropriate length, and a connector C is mounted. At this time, as shown in the figure, three sets of the optical fiber cores 2 with the protection tube 23 are grouped, and the length of each group is about 1.7 m, 1.8 m, 1.9 m, and 2.0 m. When you let
Connector _{C (C 1, C 2,} C 3, C 4) overlaps the can be reduced in the mounting portion of.

As shown in FIG. 4, each of the optical fiber cores 2 with the protective tube 23 is wound around the outer periphery of the tension member 1 at an appropriate pitch, and the wound optical fiber cores 2 are provided at required positions in the length direction. The insulating tape 28 can be wound. In this way, the stress applied to the optical fiber 2 is small even when bending is applied at the time of laying or the like. As shown in the figure, this terminal unit is housed in a well-known pooling eye B and guided to a required position. The protective cover 31 of this pulling eye B is
As a flexible pipe, for example, a metal-made spiral flexible pipe with a plastic coating facilitates installation at a bent portion at a guide point, a bending is applied to a cable terminal portion along with the bending.

As shown in FIG. 5 and Table 3, the protective tube 23 can be formed by sequentially providing a high tensile strength fiber layer 21b and a plastic sheath 22 on a plastic tube (hollow tube) 21a. In this case, the insertion of the optical fiber 2 is facilitated.

As in the present embodiment, an optical cord aggregated cable having 12 optical fiber cores 2 was manufactured with the configuration shown in Table 4 and FIG. 6, and its outer diameter was about 21.0 mmφ. It was about twice that of From this, it can be understood that the embodiment is much thinner than the optical cord aggregate type cable at the same communication capacity, and is advantageous in laying free access, floor ducts and the like.

[Effects of the Invention] Since the present invention is configured as described above, the outer diameter of the cable main body is small, and the installation space can be saved, and in the terminal portion, each optical fiber core is optically coded. In addition, since the high tensile strength fiber is fixed to the cable jacket and the tension member, the mechanical strength is large and the wiring is easy. Further, since the structure is simple, its formation is also easy.

[Brief description of the drawings]

1 is a cutaway front view of an essential part of an embodiment of an optical fiber cable according to the present invention, FIG. 2 is a perspective view for explaining the production of the embodiment, and FIG. 3 is a cross section of the optical fiber cable main body of the embodiment. FIG. 4 is a sectional front view for explaining the operation of another embodiment, and FIG.
The figure is a cross-sectional view of the protection tube, and FIG. 6 is a cross-sectional view of the optical cord assembly type cable main body. DESCRIPTION OF SYMBOLS 1 ... Tension member, 2 ... Optical fiber core wire, 5 ... Cable jacket, 21a ... Plastic tube (hollow tube), 21, 21b ... High tensile strength fiber (layer), 22 ... Plastic sheath, 23 ... Protective tube, 24 ... Binding material, 25 ... Adhesive, 26 ... Protective layer.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshio Katsui 2-3-1, Iwatacho, Higashiosaka-shi, Osaka Tatsuta Electric Wire Co., Ltd. (72) Inventor Isao Miyazaki 2-3-3, Iwatacho, Higashiosaka-shi, Osaka No. 1 Tatsuta Electric Wire Co., Ltd. (72) Inventor Yuji Uchida 2-3-1, Iwatacho, Higashi Osaka City, Osaka Prefecture

Claims (5)

(57) [Claims] An optical fiber cable is twisted around an outer periphery of a tension member together with an interposition as required, and a cable jacket is provided outside thereof. A protective tube provided with a plastic sheath at least around the outer periphery of the cylindrical high tensile strength fiber layer is inserted through the entire length of the optical fiber core wire thus exposed, and the inserted end portion of the protective tube is exposed to the high tensile strength fiber. Is secured to the cable jacket, the tension member or both so as to cover the outer periphery thereof, and a protective layer is provided over the outer periphery of the cable jacket end and the outer periphery of the plastic sheath of the protective tube. Fiber optic cable. 2. The protective tube for an optical fiber cable according to claim 1, wherein the core of the optical fiber is wound around the outer periphery of the tension member at an appropriate pitch, and an insulating tape is wound at a required interval in the longitudinal direction. A terminal portion of an optical fiber cable, which is fixed and has a different length for each or a plurality thereof, and a connector is attached to a tip of each of the optical fiber core wires. 3. An optical fiber cable comprising an optical fiber cable twisted around an outer periphery of a tension member together with an interposition as required, and a cable jacket provided outside thereof. Then, the tension member and the optical fiber core wire are exposed, and on the other hand, the plastic sheath at one end of a protective tube provided with a plastic sheath on the outer periphery of the cylindrical high tensile strength fiber layer is stripped off by a required length, and the exposed optical fiber is exposed. The protective tube is inserted into the entire length of the cord from the stripped end of the plastic sheath, and the exposed high tensile strength fiber is covered on the outer periphery of the cable jacket, the tension member or both, and is fixed with an adhesive, and the cable is fixed. Cover the outer periphery of the outer sheath and the outer periphery of the plastic sheath of the protective tube with a heat-shrinkable tube and heat-shrink or insulate. Method of forming an optical fiber cable, characterized in that by winding-loop providing a protective layer. 4. The optical fiber core wire with a protective tube of the optical fiber cable according to claim 1 is cut so that its length differs for each or a plurality of wires, and a connector is provided at each cut end. A method of forming an end portion of an optical fiber cable, comprising, after mounting, winding around an outer periphery of a tension member at an appropriate pitch, and winding and fixing an insulating tape at a required position in the length direction of the wound optical fiber core wire. . 5. A protective tube used in the forming method according to claim 3, wherein a cylindrical high tensile strength fiber layer and a plastic sheath are sequentially provided on the plastic tube.