JPS6290604A - Method for terminating optical fiber cable - Google Patents

Abstract

PURPOSE:To make sure moisture-proofing treatment of the terminal of an optical fiber cable without damaging the optical fiber cores by inserting protective tubes onto the optical fiber cores, inserting a cylindrical body onto the optical fibers and packing a moisture-proof intimate mixture therein. CONSTITUTION:Sheaths 3 and cable cores 4 at the terminal of the optical fiber cable 1 are first stripped to expose the respective optical fiber cores 2 and tensile bodies 11 by a prescribed length. The protective tubes 5 cut to a prescribed length are respectively inserted onto the cores 2 and after the tubes 5 are adhered and united by an adhesive agent, an adhesive tape 6 is wound around the tubes to approximately the same diameter as the diameter of the cable 1. The cylindrical body 7 is fitted onto the cable 1 and thereafter moisture- proofing intimate mixture 10 is poured from the other end and is packed into the cylindrical body 7. A heat shrinkable tube 8 is finally put on the end of the cylindrical body 7 on the cable 1 side upon curing of the mixture 10 is heated to fix the cylindrical body 7 to the cable 1. The sure moisture-proofing treatment of the cable terminal is thereby executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for terminating an optical fiber cable formed by collecting a plurality of optical fibers.

[Prior art and its problems]

When transmitting data between station buildings using optical fiber cables, the optical cables are usually laid separately inside the station building and outside the station building, and the two are connected via a connector attached to the end of each cable. It is said that

When attaching a connector to an optical fiber cable, the outer sheath of the optical fiber cable terminal is peeled off to take out the optical fiber core, but if this cable terminal is left as is, moisture will enter the optical fiber cable. There is a problem in that dew condensation occurs within the cable due to subsequent temperature changes and the like, degrading the transmission characteristics of the optical fiber cable in the long wavelength band.

Therefore, as shown in Japanese Patent Application Laid-Open No. 52-55649, the terminals of optical fiber cables have been subjected to moisture-proofing treatment.

FIG. 2 is a sectional view showing a conventional optical fiber cable that has been subjected to terminal treatment.

In the figure, reference numeral 20 denotes an optical fiber cable, and at its terminal, the jacket 21 is peeled off, the cable core 22 and the optical fiber core 23 are exposed in stages, and a pipe 24 is fitted over the cable core 22 and the optical fiber core 23. ing.

A partition wall 25 is formed in the middle of the pipe 24,
The partition wall 25 is formed with a number of insertion portions 26 through which the optical fibers 23 are inserted, depending on the number of the optical fibers 23, and a terminal cap (not shown) or the like is provided on the outer periphery of the tip end thereof. A male screw 27 to be screwed is provided.

Then, a moisture-proof admixture is filled between the optical fiber cable 20 and the pipe 24, and the optical fiber cable 20
Moisture-proof protection inside.

However, in such a terminal structure, the partition wall 25
Since the moisture-proof admixture is not filled in the insertion part 26 of There was a risk that moisture could flow in, making it impossible to obtain a complete moisture-proofing effect and having an adverse effect on optical communication equipment.

Further, since the optical fiber coated wire 23 is inserted as it is through the insertion portion 26 of the partition wall 25, there is a problem that the optical fiber coated wire 23 comes into contact with the end portion of the insertion portion 26 and is easily damaged.

Further, an insertion portion 26 formed near the bottom of the pipe 24
Since it is very difficult to insert each optical fiber core 23 one by one through the cable, conventionally the manufacturer has delivered optical fiber cables whose terminals have been pre-processed as shown in FIG. 2. Therefore, there is an inconvenience in that it is not possible to cut the optical fiber cable at the site according to the installation situation and to freely perform terminal processing at the cut location.

[Purpose of the invention]

SUMMARY OF THE INVENTION Therefore, the present invention provides an optical fiber cable that can reliably moisture-proof the end of an optical fiber cable without damaging the optical fiber core, and can easily perform terminal treatment on a cut optical fiber cable at the site. The purpose is to provide a terminal processing method.

[Structure of the invention]

In order to achieve this object, the optical fiber cable terminal processing method according to the present invention involves peeling off the outer sheath of the optical fiber cable terminal and removing a plurality of optical fiber cores from the cable terminal by a predetermined distance from the cable terminal. Protective tubes of a predetermined length are fitted onto separate locations, and a rigid cylindrical body is fitted onto the outside to cover the space between the protective tubes and the cable end, and one end of the cylindrical body is heated. After fixing to the protective tube or cable terminal with a shrinkable tube and filling the moisture-proof admixture into the cylindrical body from the other end, the other end is fixed to the protective tube or the cable terminal with a heat-shrinkable tube. It is characterized by the following.

[Action of the invention]

According to the method of the present invention, since there is an exposed portion of the optical fiber core inside the cylindrical body, the moisture-proof admixture is filled into the cylindrical body without any gaps, and a protective tube is inserted through each optical fiber core. Therefore, the optical fiber core is reinforced, and both ends of the cylindrical body are tightly fixed to the optical fiber cable and protection tube with heat shrink tubes, so moisture-proofing can be reliably applied, and at the same time the cylindrical body is strong. will be installed on the

In addition, since it is a simple method of inserting a protective tube into each optical fiber core, fitting a cylindrical body around the outside, and filling it with a moisture-proof admixture, the optical cable can be cut at the site according to the installation situation, and the relevant Terminal treatment can be easily applied to the cut location.

〔Example〕

Hereinafter, the present invention will be explained based on specific embodiments shown in the drawings.

FIG. 1 is a cross-sectional view showing an optical fiber cable using the method of the present invention.

In the figure, reference numeral 1 denotes an optical fiber cable formed by covering a plurality of optical fiber cores 2 with a sheath 3 and a cable core 4, and the sheath 3 and cable core 4 are peeled off at the terminal end. The optical fiber cores 2.2.- are exposed.

Reference numeral 5 denotes a polyethylene protective tube that is fitted over and covers each optical fiber core 2 exposed from the optical fiber cable l, and is spaced a predetermined distance from the cut end of the cable core 4. They are positioned and fixed to each other with an adhesive, and an adhesive tape 6 is wound around them to integrate them.

Reference numeral 7 denotes a rigid cylindrical body such as an aluminum sleeve, which is fitted between the end of the optical fiber cable 1 and the protective tube 5, and one end of which is provided with a heat-shrinkable tube 8 that protects the optical fiber. The protective tube 5 is fixed to the end of the fiber cable 1 and is integrated with the heat shrinkable tube 9 from the other end by wrapping it with an adhesive tape 6.
Fixed.

The interior of the cylindrical body 7 is filled with a moisture-proof admixture 10 made of, for example, polyurethane resin without any gaps, thereby reliably moisture-proofing the end portion of the optical fiber cable 1.

Note that 11 is a tensile strength member called a tension member made of a steel wire or the like arranged in the center of the optical fiber cable 1 to prevent the optical fiber core 2 from breaking due to the tension acting on the optical fiber cable 1. .

The above is an example of the configuration of an optical fiber cable using the method of the present invention, and the terminal processing method thereof will now be described.

First, at the terminal end of the optical fiber cable 1, the jacket 3 and cable core 4 are peeled off, and each optical fiber core 2 is removed.
Then, the tensile strength member 11 is exposed for a predetermined length, for example, 5 to ioam).

Next, the protective tube 5 cut to a predetermined length is inserted into each exposed optical fiber core 2, and the cable core 4 is
are arranged around the tensile strength member 11 at a predetermined distance from the end of the optical fiber cable L, and after the protective tube 5 is glued and integrated with an adhesive, Adhesive tape 6 is wound around it.

After fitting the cylindrical body 7 on the outside of the optical fiber cable l, one end of the cylindrical body 7 is fixed to the optical fiber cable 1 or the protective tube 5 using a heat shrink tube 8 or 9. Then, the moisture-proof admixture 10 is poured into the cylindrical body 7 from the other end.

Here, when the cylindrical body 7 is first fixed to the protective tube 5, the cylindrical body 7 is fitted onto the outside so that the protective tube 5 protrudes from the tip of the cylindrical body 7, and the heat shrink tube 9 is placed over the cylindrical body 7. After heating and fixing, the moisture-proof admixture 10 is poured into the cylindrical body 7 from the end on the optical fiber cable 1 side and hardened.

At this time, since the protective tube 5 is located a predetermined distance away from the cut end of the cable core 4, an exposed portion of the optical fiber core 2 exists within the cylindrical body 7, and the optical fiber cable The end portion of No. 1 is reliably covered with the moisture-proof admixture lO without any gaps and is moisture-proofed.

Finally, after the moisture-proof admixture 10 has hardened, a heat shrink tube 8 is placed over the end of the cylindrical body 7 on the optical fiber cable 1 side and heated.
Fixed to.

If the tensile strength member 11 is made of a single wire, there is no problem even if it is exposed from the tip of the optical fiber cable 1 in the same way as the optical fiber core 2 as shown in FIG. If it is made up of stranded wires, moisture may flow into the optical fiber cable l through the gaps between the strands, so the tensile strength member 11 is cut short and the tip is attached to the moisture-proof admixture 11. It is better to bury it inside.

In addition, the optical fiber cable 1 that has been terminal-treated in this way
When connecting a connector, optical communication equipment, etc. to the connector, the optical fiber cable 1 can be fixed to the connector etc. via the cylindrical body 7, and the connection can be made without putting any burden on the optical fiber core 2. be able to.

In addition, in the description of the above-mentioned embodiment, only the case where the moisture-proof admixture 10 is poured into the cylindrical body 7 from the end on the optical fiber cable l side and filled, but the present invention is not limited to this, and the protection tube 5 It may also be filled by pouring from the side end.

〔Effect of the invention〕

As described above, according to the method of the present invention, since there is an exposed portion of the optical fiber core inside the cylindrical body fitted over the end of the optical fiber cable, when the moisture-proof admixture is filled into the cylindrical body, This has the effect of being able to cover the cable end without any gaps and ensuring moisture proofing.

Furthermore, since both ends of the cylindrical body are sealed and fixed by the heat-shrinkable tube, there is an effect that moisture will not enter into the cylindrical body filled with the moisture-proof admixture.

Furthermore, since each coated optical fiber is inserted into the protective tube, the coated optical fiber does not come into contact with the cylindrical body or the tip of the cured moisture-proof admixture and be damaged. The optical fiber core is reinforced at the tip of the cylindrical body and is less likely to be damaged by bending.

Furthermore, since the protective tube can be individually inserted into each optical fiber core, terminal processing can be easily performed, and therefore the optical cable can be cut according to the installation conditions at the optical cable installation site. There is an excellent effect that terminal treatment can be freely applied to the cut portion.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an optical cable using the method of the present invention, and FIG. 2 is a sectional view showing an optical cable which has been terminal-treated using a conventional method. Explanation of symbols 1--Optical cable, 2--Optical fiber core, 3--Sheath, 4--Cable core, 5--Protection tube, 6--
.... Adhesive tape, 7-.-Cylindrical body, 8, 9-.Heat shrinkable tube, 10-.-Moisture-proof admixture, 11-Tensile strength body.

Claims (1)

[Claims] A protective tube of a predetermined length is fitted over each of the multiple optical fiber cores taken out by peeling off the outer sheath of the optical fiber cable terminal at a predetermined distance from the cable terminal. A cylindrical body is fitted externally to cover between the protective tube and the cable terminal, one end of the cylindrical body is fixed to the protective tube or the cable terminal with a heat-shrinkable tube, and the cylinder is inserted from the other end. A method for processing an end of an optical fiber cable, which comprises filling a moisture-proof admixture into a shaped body and then fixing the other end to the protective tube or the cable terminal using a heat-shrinkable tube.