JP2745729B2 - Branch of optical fiber cord with connector - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a branch portion of an optical fiber cord with a connector.

[Prior Art] With the increase in the density of optical fiber cables, the demand for optical tape cables using optical fiber ribbons is increasing. When this optical tape cable is connected to a device using a termination box, an optical fiber cord with a connector has conventionally been used. The optical fiber cord accommodates a single optical fiber core, and the optical fiber cable has a structure in which a single optical fiber core is accommodated in a plurality of plastic spacers or the like. The optical fiber ribbon is obtained by covering a plurality of optical fibers at once, and when attaching a connector, it is necessary to separate and optically code each fiber. However, if this operation is performed in the termination box and optical coding is performed for each fiber, a huge number of connection parts must be accommodated in the termination box, and a huge number of optical codes must be distinguished and connected to the equipment with connectors. Need to connect. In order to solve this, means for reducing the splice and the optical cord by splicing each optical fiber tape and converting the optical fiber ribbon into an optical code, separating the optical fiber tape before entering the device and attaching a connector to each optical fiber. Is used.

FIGS. 3, 4 and 5 show an example of a two-core optical fiber cord. FIG. 3 is a cross-sectional view of an optical fiber cord, a longitudinal section of a branch portion of an optical fiber cord with a connector, and a cross-section of a protective tube. The figure is shown.

In these figures, 1a is an optical fiber, 1b is an ultraviolet curable resin, 1 is an optical fiber 1a, an optical fiber wire formed of an ultraviolet curable resin 1b, 2 is a two-core optical fiber 1 and an ultraviolet curable resin. 3 is an optical fiber cord core formed by the conductive resin 1b, 3 is an optical fiber cord core 2, a high-tensile fiber Kevlar (trade name of DuPont), 4 is a sheath for covering the Kevlar 3, and 5 is The optical fiber cord to be formed, 6 is a sleeve for covering the end of the optical fiber cord 5, 7 is a heat-shrinkable tube for bringing the optical fiber cord 5 into close contact with one end of the sleeve 6, and 8 is a fixing for fixing the Kevlar 3 together. A metal fitting, 9 is an end face plate fixed to the other end of the sleeve 6, 10 is a protective tube that penetrates and protects the optical fiber 1, 1a is a nylon pipe for covering the optical fiber 1, and 10b is a nylon pipe. Kevlar to the exterior of the pipe 10a, 10c sheath for sheathing the Kevlar 10b, 11 is an optical connector is attached to the distal end side of the protective tube 10, 12 is a fixing member for fixing the protective tube 10 to the end plate 9.

In FIGS. 3 to 5, the outer circumference of the optical fiber 1a is formed by coating the outer periphery of the optical fiber 1a with the ultraviolet curing resin 1b. Line 2 is formed. Next, a Kevlar 3 is longitudinally attached as a tension member to the outer periphery of the optical fiber cord 2 and the sheath 4 is covered to form an optical fiber cord 5. When attaching the optical connector 11 to the optical fiber cord 5, the sheath 4 at the end of the optical fiber cord 5 is removed to expose the Kevlar 3 and the optical fiber cord 2, and the optical fiber cord 2 is separated for each fiber. Optical fiber 1
Perform in the state of. A portion where the optical fiber cord 2 is separated into the optical fiber 1 is covered with a sleeve 6 for protection. The sleeve 6 is fixed to the sheath 4 of the optical fiber cord 5 with a heat-shrinkable tube 7. The Kevlar 3 is collectively swaged to the fixing bracket 8 and fixed by a method such as bonding. The fixing bracket 8 is fixed to the end face plate 9 fixed to the sleeve 6. On the other hand, the optical fiber 1 is passed through a hole provided in the end plate 9, pulled out of the sleeve 6, and inserted into the protective tube 10. The terminal of the protective tube 10 is fixed to a protective tube fixing bracket 12, and the optical connector 11 is attached to the other terminal. In this way, the optical fiber 1 is connected to the nylon pipe 10a of the protective tube 10.
And is protected from external forces (Fig. 5).

[Problem to be Solved by the Invention] As described above, the branch portion of the optical fiber cord is formed, but in this case, some problems still remain.
That is, there are many parts constituting the branching part, and much time is required for assembly. Further, since a space for fixing the high-tension fiber Kevlar is required, the space and weight of the branch portion are increased, which makes handling inconvenient. Furthermore, since the arrangement of the optical fiber cannot be observed during the assembling work, even if twisting or bending occurs, it cannot be corrected, and there is a tendency to lower the reliability.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned disadvantages of the prior art, to reduce the size and cost of the branch, and to greatly improve the assembling workability to improve the reliability of the branch with the optical fiber tape cord with connector. Is to provide.

[Means for Solving the Problems] The present invention provides an optical fiber which is formed by coating a multi-core optical fiber with a resin at a time, coating the optical fiber with a high-tensile fiber, and then covering the optical fiber with a sheath. The optical fiber comprises a fiber cord, a protective tube formed of an insulating pipe, a high-tensile fiber and a sheath and protecting the penetrating optical fiber from external force, and an optical connector attached to a distal end of the protective tube and connected to an external device. In the branch portion of the optical fiber cord with connector for connecting and fixing the optical fiber cord and the protective tube and branching light passing through the optical fiber cord through a connector, the high-tensile fiber in the protective tube is placed on the protective tube. It is folded back at a certain length, and the high-tensile fiber in the optical fiber tape cord is vertically attached on the high-tensile fiber, and heating is applied on both high-tensile fibers. A heat-shrinkable tube that shrinks and presses both the high-tensile fibers and the protective tube is coated, and a transparent plastic pipe is disposed outside the tip of the heat-shrinkable tube and the optical fiber cord so as to straddle both of them, Outside the plastic pipe,
It is characterized by a transparent heat-shrinkable tube that shrinks by heating and fixes the optical fiber cord and the protective tube together through a plastic pipe to form a branch part. The goal is achieved by making it easier and more reliable.

[Operation] In the branch portion of the optical fiber cord with connector of the present invention, after arranging the optical fiber cord and the protective tube so as to face each other, the kevlar of the protective tube is turned over and arranged on the sheath of the protective tube. A kevlar of the cord is laid vertically on top of this, a plurality of protective tubes constructed in this way are wrapped together with a heat-shrinkable tube, and the tip of the optical fiber cord is also surrounded with a heat-shrinkable tube. Heat shrink the tube and fix it, then pass one optical fiber wire through each protective tube, cover the transparent Teflon tube so as to straddle both heat shrink tubes, and further put a transparent heat shrink tube on top The optical fiber cord and protective tube are covered with Kevlar, heat-shrinkable tube, and Teflon It can be fixed integrally by the heat shrink tube on the outside and the outermost circumference, which makes assembly work easier and the branch part can be firmly fixed. Performance can be greatly improved.

Example An example of the present invention will be described below with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing one embodiment of a branch portion of an optical fiber cord with a connector according to the present invention, and FIGS. 2 (a) to 2 (e) show an assembly work process of the branch portion shown in FIG. In the drawings, the same parts as those in FIGS. 3 to 5 are denoted by the same reference numerals.

In both figures, 13 is a Kevlar folded over the protective tube 10, 14 is a Kevlar vertically attached on it, 15 is a heat-shrinkable tube covered on both Kevlars 13 and 14, and 16 is an optical fiber cord Heat-shrinkable tube over the tip of 5, 17
Is a transparent Teflon pipe fitted so as to straddle both heat-shrinkable tubes 15 and 16, and 18 is a transparent heat-shrinkable tube further covered thereon.

Hereinafter, an operation process for assembling the branch portion will be described with reference to FIG.

(1) Strip the end portion of the optical fiber cord 5 on the optical connector 11 side by a required length to expose the two-core optical fiber core wire 2 and the Kevlar 3. Next, the two-core optical fiber core 2 is separated for each core to obtain the optical fiber 1. The Kevlar 3 is cut to a length necessary for fixing (FIG. 2A).

(2) Prepare the necessary length of the optical fiber 1 and the protective tube 10 separated for each core, peel off the sheath 10c at one end to the required length, and remove the nylon pipe 10a and Kevlar 10b.
To expose. The nylon pipe 10a and the Kevlar 10b are cut to required lengths (FIG. 2 (b)).

(3) The optical fiber cord 5 and the two protection tubes 10 are opposed at an arbitrary interval, and the Kevlar 10b of the protection tube 10 is provided.
Is folded evenly around the outer periphery of the sheath 10c to form a folded portion 13,
Further, the Kevlar 3 of the optical fiber cord 5 is connected to the protective tube 10.
The sheath 10c is uniformly longitudinally attached to the outer periphery of the sheath 10c to form a longitudinal attachment portion 14 (FIG. 2 (c)).

(4) Optical fiber cord 5 and protective tube
The heat-shrinkable tubes 16 and 15 (with an inner adhesive) passed through the two heat-shrinkable tubes 10 and 16 are arranged at predetermined positions, and the heat-shrinkable tubes 15 and 16 are heat-shrinked to form the Kevlar 3 and 10b and the protective tube 10. The two are fixed and integrated. In this case, the heat-shrinkable tube 16 on the side of the optical fiber cord 5 serves as a dummy for adjusting the outer diameter of the heat-shrinkable tube 16 to the facing protective tube 10. Thereafter, the optical fiber 1 is inserted into the nylon pipe 10a of the protective tube 10 one by one (FIG. 2 (d)).

(5) (T)
(FIG. 2 (e)).

(6) The heat-shrinkable tube 18 (with the inner surface adhesive) passed through in advance is placed on the Teflon pipe 17 and shrunk by heating. The length of the heat-shrinkable tube 18 is longer than that of the Teflon pipe 17 and is substantially the same as the length of the heat-shrinkable tubes 15 and 16 to the ends.

Thus, the branch portion is completed (FIG. 1). Thereafter, the connector 11 is attached to the end of the protective tube 10 to complete the optical fiber cord with the connector.

In the above-described embodiment, the case where the number of the optical fiber cords is two is described. However, this can be applied to the case where the number of the optical fiber cords is multiple. Further, a Teflon pipe is used as a pipe for protecting the branch portion, but any material may be used as long as it has heat resistance and the inside can be visually checked. Also,
As a method of fixing the Kevlar, the Kevlar is fixed to the protective tube side and fixed by the heat shrink tube, but may be fixed to the optical fiber cord side collectively. In this case, a good result can be obtained by covering a heat-shrinkable tube for fixing a plurality of protective tubes at once.

[Effects of the Invention] As described above, according to the present invention, the following effects can be obtained.

(1) By integrating the protective tube with the heat-shrinkable tube and fixing the Kevlar at the same time, the practical tensile strength of the branch portion and the handleability of the protective tube can be improved.

(2) Since the inside of the Teflon pipe that protects the branching portion is visible, abnormalities such as twisting and bending of the optical fiber at the time of assembly can be grasped. Further, the influence of heat during the heat shrinkage of the heat shrinkable tube placed on the outer periphery of the Teflon pipe can be prevented by the Teflon pipe, and the characteristics of the optical fiber can be maintained.

(3) The reliability can be improved by reducing the size and cost of the branch portion.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a branch portion of an optical fiber cord with a connector according to the present invention, FIG. 2 is an explanatory view of an assembling work process of the branch portion shown in FIG. 1, and FIG. FIG. 4 is an explanatory view of a conventional optical fiber cord with a connector, and FIG. 5 is a transverse sectional view of the protective tube shown in FIG. 1: Optical fiber strand, 1a: Optical fiber, 1b: UV curable resin, 2: Optical fiber cord core, 3: Kevlar, 4: Sheath, 5: Optical fiber cord, 10: Protective tube, 10a: Nylon pipe 10b: Kevlar, 10c: Sheath, 11: Optical connector, 13: Folded part of Kevlar 10b, 14: Vertical attachment part of Kevlar 3, 15, 16: Heat shrink tube, 17: Teflon pipe, 18: Heat shrink tube.

Claims (1)

(57) [Claims] 1. An optical fiber cord formed by coating a multi-core optical fiber with a resin at a time and coating and covering an optical fiber cord with a high-tensile fiber and a sheath, an insulating pipe, a high-tensile The optical fiber cord comprises: a protective tube formed of a fiber and a sheath for protecting the penetrating optical fiber wire from external force; and an optical connector attached to a distal end of the protective tube and connected to an external device. At a branch portion of the optical fiber cord with connector for connecting and fixing a tube and branching light transmitted through the optical fiber cord through the optical connector, the high-tensile fiber in the protective tube has a predetermined length on the protective tube. The high-tension fiber is vertically attached to the high-tension fiber, and the high-tension fiber is heated by heating. A heat-shrinkable tube that shrinks and presses the high-tensile fibers and the protective tube is coated, and a transparent plastic pipe is disposed outside the distal end of the heat-shrinkable tube and the optical fiber cord so as to straddle both. The plastic pipe is covered with a transparent heat-shrinkable tube which shrinks by heating and integrally fixes the optical fiber cord and the protective tube via the plastic pipe. Branch of optical fiber cord with connector to be used.