JPH0688927A - Optical fiber cable with gas dam - Google Patents

Abstract

PURPOSE:To make the injection of compds. possible without moving optical fiber cables and a gas dam part by providing sheath end sides with injection port and blow-off ports for the compds., respectively and further providing these injection port near the center of the gas dam. CONSTITUTION:The end sides of the outer sheaths 3a and inner sheaths 3b of the optical fiber cables 3 are respectively provided with the injection port 8a and the blow-off ports of the compds. Further, the injection port 8a are provided near the center of the gas dam. The compds. are injected from the injection port 8a and are made to overflow from the blow-off port 8b. The compds. 6 are packed into the spacing parts between the optical fibers 1 and the tension members 2. The compds. 6a, 6b are packed into the part where the optical fiber cables 3 are peeled. As a result, the venting of bubbles is perfected and the need for the operation to perpendicularly move the optical fiber cable and the gas dam part for the purpose of expelling the bubbles is eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides an optical fiber cable with a gas dam in which a compound can be injected without moving the gas dam portion and the optical fiber cable while they are placed sideways.

[0002]

2. Description of the Related Art A conventional optical fiber cable with a gas dam is disclosed in Japanese Utility Model Publication No. 3-56903. As shown in FIG. 2, when the gas dam d is provided between the optical fiber a and the optical fiber cable c having the tension member b, the coating of the intermediate portion of the optical fiber cable c is stripped off and the tension member b is removed.
, The spacer e of the optical fiber a is removed, and the tension member b is connected via the joint metal fitting f. Next, the optical fiber cable is fixed by inserting the sealing tube g located on the left side in FIG. 2 into the case h, with the optical fiber cable c located on the left side facing down and the optical fiber cable c located on the right side facing up. To do. After that, the tension member b is inserted into the central hole of the image wall plate i through the split of the image wall plate i, and the optical fiber a is inserted into the outer groove. Then, at a predetermined position, the gap between the image wall slope i, the optical fiber a, and the tension member b is sealed with a quick-curing rubber compound j. Next, the case k is lifted up, and when the image wall plate i is positioned at the step inside the case k, the sealing tube g is fitted to fix the case h.
Then, a certain amount of the compound j is injected from the opening portion of the case h, and after the compound j is cured, a screwing portion of the lid m and the case h is filled with a sealing material (tape, oil, etc.), and both are fitted. At the same time, they are fixed together by fixing screws n. After that, the sealing tube g on the lid m side is fitted. The conventional optical fiber cable with a gas dam has the above-described configuration.

[0003]

In the prior art as described above, when the compound j is injected from the injection port provided in the gas dam, in order to prevent air bubbles from being mixed in the compound j, the gas dam d and the The optical fiber cable section c had to be kept in a vertically standing state. Further, in the case where the gas dam d part has the outlet of the compound j inclined to the side, there is a problem that the compound will blow out before the compound j is fully filled in the gas dam d part. is there. The present invention intends to solve such a conventional problem.

[0004]

The present invention is an optical fiber cable with a gas dam in which a gas dam is provided in the middle of the optical fiber cable.
a and the same outlet 8b are provided on both sheath end sides, respectively, and further, a compound injection port 8a is provided near the center of the gas dam, whereby the injection of the compound can be performed without moving the optical fiber cable and the gas dam part. The configuration is such that the inclusion of air bubbles is avoided.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention.
In the figure, 1 is an optical fiber, 2 is a tension member, 3 and 3 are optical fiber cables, 3a and 3a.
Is an outer sheath made of polyethylene, 3b and 3b are inner sheaths made of polyethylene, and 3c and 3c are spacers of the optical fiber 1. 3d and 3e adhesive interposition tape, wherein the outer sheaths 3a, 3a and the inner sheaths 3b, 3b are
However, since the adhesiveness to the compound described below is poor, it is intended to improve the adhesiveness by playing a relaying role in joining the both. The adhesive interposition tape 3e is also designed to have a sealing effect on the ends of the outer sheaths 3a and 3a.

Reference numeral 4 is a beam, 5 is a joint fitting for connecting the tension member 2, and 6 is a fast-curing compound for filling the gap between the optical fiber 1 and the tension member 2 to provide sealing. belongs to. 6a,
6b is a compound that is filled in the step-peeled portions of the optical fiber cables 3 and 3. 7 is a cylindrical case body,
Reference numeral 7a is a protective case housed inside. Although 8a is a compound injection port and 8b is a compound blowout port, which is omitted in the drawing, the injection port 8a and the blowout port 8b are each configured to be sealed by a screw.

Reference numeral 9 denotes a picture wall plate, and 9a denotes a picture wall cylinder, which is for fitting the picture wall plate 9 to the joint fitting 5 and then fitting it to the outside of the picture wall plate 9. The compound 6 is injected in the fitted state of the picture wall cylinder 9a. 10 is a sealing tube having heat shrinkability, and 11 is a sealing member provided near the tip of the sealing tube 10 and is formed of a tape material or a synthetic resin material. Reference numeral 12 is an O-ring, which is for respectively performing a sealing action on a required portion.

In the embodiment shown in FIG. 1, the optical fiber cable is cut at a predetermined design position, the tension member 2 arranged at the center thereof is fixed by a joint metal fitting 5, and the tension member 2 is Between the optical fibers 1 arranged in the circumferential direction and the optical fiber cable 3
Between the end portion of A and the position A shown in the figure, the filled and cured compounds 6, 6a, 6b are provided, and these are covered with a protective case 7a, and the whole case is removable by a cylindrical case body 7. It is configured to cover.

By the way, in the illustrated embodiment, the beam 4
By arranging three of them in the gas dam portion, the optical fiber cable is cut and fixed by the joint fitting 5, and then the cable is prevented from being twisted. That is, in the conventional case, the optical fiber cable is apt to be twisted during the work, and thus it took time and labor to fix it. However, based on the arrangement of the beam 4, such a problem is solved, In addition, the effect of preventing twisting after completion is achieved.

An important point in the present invention is the location of the compound injection port 8a and the compound injection port 8b. That is, in the present invention, the compound inlet 8a and the same outlet 8b are provided on both sheath end sides, respectively, and further, the compound inlet 8a is provided near the center of the gas dam. The technical point is that the injection portions are formed at a total of three locations on both ends of the sheath and the central portion of the gas dam. Based on the above configuration,
By injecting the compound from the injection port 8a and overflowing it from the ejection port 8b, it is possible to complete the removal of bubbles, and to move the optical fiber cable and the gas dam part vertically to eliminate bubbles as in the conventional case. Such work becomes unnecessary, and work can be continued in the same state as the previous process.

Regarding the internal structure of the gas dam,
By arranging the position where the compound inlet is connected to the compound outlet in the highest part, it is possible to prevent the inclusion of air bubbles.

[0012]

According to the present invention, the compound inlet 8a and the same outlet 8b are provided on both sheath end sides, respectively, and the compound inlet 8a is provided near the center of the gas dam. Therefore, as described above, the compound injection work can be performed in the same state as the process before the compound injection without vertically moving the gas dam portion and the optical fiber cable as in the conventional case. Therefore, the work time and labor can be reduced, and at the same time, the problem that the appearance of the optical fiber cable is damaged due to the movement is eliminated. Further, according to the present invention, since the injection portion of the gas dam is provided not only at the central portion of the gas dam but also at the end portions of both sheaths, the airtightness is remarkably improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a conventional optical fiber cable with a gas dam.

[Explanation of symbols]

 1 Optical fiber 2 Tension member 3 Optical fiber cable 3a Outer sheath 3b Inner sheath 3c Spacer 3d Adhesive intervening tape 3e Adhesive intervening tape 4 Beam 5 Joint metal 6 Compound 6a Compound 6b Compound 7 Case body 7a Protective case 8a Compound injection port 8b Compound blowing Outlet 9 Wall panel 9a Wall cylinder 10 Sealing tube 11 Sealing member 12 O-ring

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] September 17, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

[0012]

According to the present invention, the compound inlet 8a and the same outlet 8b are provided on both sheath end sides, respectively, and the compound inlet 8a is provided near the center of the gas dam. Therefore, as described above, the compound injection work can be performed in the same state as the process before the compound injection without vertically moving the gas dam portion and the optical fiber cable as in the conventional case. Therefore, the work time and labor can be reduced, and at the same time, the problem that the appearance of the optical fiber cable is damaged due to the movement is eliminated. Further, according to the present invention, since the injection portion of the gas dam is provided not only at the central portion of the gas dam but also at the end portions of both sheaths, the airtightness is remarkably improved.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a conventional optical fiber cable with a gas dam.

[Explanation of symbols] 1 optical fiber 2 tension member 3 optical fiber cable 3a outer sheath 3b inner sheath 3c spacer 3d adhesive intervening tape 3e adhesive intervening tape 4 beam 5 joint metal fittings 6 compound 6a compound 6b compound 7 case body 7a protective case 8a compound Inlet port 8b Compound air outlet 9 Drawing wall plate 9a Drawing wall tube 10 Sealing tube 11 Sealing member 12 O-ring

Front page continuation (72) Inventor Katsunori Nakano 5-1-1 Hidaka-cho, Hitachi City, Ibaraki Prefecture Hitachi Cable Co., Ltd. Hidaka Plant (72) Inventor Nobuaki Watanabe 5-1-1 Hidaka Town, Hitachi City, Ibaraki Prefecture No. 1 Hitachi Cable Co., Ltd. Hidaka factory

Claims (1)

[Claims] 1. An optical fiber cable with a gas dam in which a gas dam is provided in the middle of the optical fiber cable, the compound injection port (8a) and the compound air outlet (8b).
And a gas injection port (8a) near the center of the gas dam. An optical fiber cable with a gas dam.