JP4043924B2 - Optical cable connection - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical cable connecting portion suitable for connection between an outdoor drop cable and an indoor optical cable.
[0002]
[Prior art]
An optical cable as shown in FIG. 5A or 5B is used for the outdoor drop cable and the indoor optical cable. The optical cable 10 in (A) is obtained by covering an optical fiber core wire 12 and a tension member 14 arranged in parallel on both sides with a common jacket 16. The cross-sectional shape of the jacket 16 is flat because the optical fiber core wire 12 and the tension member 14 are arranged in the same plane. Further, a tearing groove 18 is formed in the jacket 16 in order to make it easy to take out the optical fiber core wire 12 at the time of connection or the like.
[0003]
Further, in the optical cable 10 of (B), tension members 14 are arranged in parallel on both sides of the optical fiber core wire 12, and a tension member 20 that is thicker than the tension member 14 is arranged in parallel on the outside of one tension member 14. A common jacket 16 is put on. Grooves 18 and 22 are formed in the jacket 16.
[0004]
In the optical cable 10 shown in FIGS. 5A and 5B, the number of the optical fiber cores 12 is one, but the number of the optical fiber cores 12 may be two. In any case, this type of optical cable is a small-core optical cable having a small number of optical fiber cores.
[0005]
Conventionally, even when such a low-core optical cable is connected, the connection is performed using a closure that can accommodate the connection length of the optical fiber core wire.
[0006]
[Problems to be solved by the invention]
However, the conventional optical cable connecting portion using the closure has a problem that not only the installation space is required, but also the connecting work is troublesome and the cost is high.
[0007]
The objective of this invention is providing the optical cable connection part which solved the above subjects.
[0008]
[Means for Solving the Problems]
The optical cable connecting portion according to the present invention is a flat optical cable connecting portion covering a common jacket on a small number of optical fibers and tension members,
An elongated box provided with a slot into which an optical cable is press-fitted on both end walls, and a heat-shrinkable tube having a thickness that allows insertion of the elongated box and is longer than the elongated box and having a hot melt adhesive layer on the inner surface. use,
Connect the exposed optical fiber by stripping the jacket of the end of the optical cable to be connected, and cut the tension member.
The exposed optical fiber and its connecting portion are accommodated in the elongated box, and the jacket portions of both optical cables are press-fitted into the slots at both ends of the elongated box, and fixed.
Covering the elongated cable and the optical cable near its both ends with the heat shrinkable tube, heat shrinking at least both ends of the heat shrinkable tube, and adhesively fixing the elongated box and the optical cable near its both ends.
It is characterized by this.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0010]
Embodiment 1 FIG. 1 shows an embodiment of the present invention. In the figure, 10A and 10B are optical cables to be connected, 12A and 12B are optical fiber core wires 16A and 16B that are stripped and exposed at the ends of the optical cables 10A and 10B, 14A and 14B are tension members, and 24 is a tension member. It is a connection part of optical fiber core wire 12A, 12B. The tension members 14A and 14B are cut in the vicinity of the cut end faces (or cut end faces) of the jackets 16A and 16B, and the tip is removed. The optical fiber core connection part 24 removes the coating on the ends of the optical fiber cores 12A and 12B to expose the bare optical fiber, and after the bare optical fiber is fusion spliced, it is covered with a reinforcing sleeve and thermally contracted. It is a thing. The optical fiber core connection portion 24 may have a structure other than the above as long as the connection portion of the bare optical fiber is reinforced against tension or bending.
[0011]
Reference numeral 26 denotes an elongated box that accommodates the exposed optical fiber cores 12A and 12B and their connecting portions 24, and 28 denotes a heat-shrinkable tube that covers the elongated box 26 and the optical cables 10A and 10B near both ends thereof. .
[0012]
As shown in FIG. 2, the elongated box 26 is provided with slots 32 into which optical cables are press-fitted into the walls 30 at both ends. The elongated box 26 is formed of a high-strength material such as a metal (for example, stainless steel) so as not to be easily deformed. As shown in FIG. 1, the portions of the jackets 16A and 16B of the optical cables 10A and 10B are press-fitted into the slots 32 at both ends of the elongated box 26, respectively.
[0013]
Since the optical cables 10 </ b> A and 10 </ b> B are flat, the press-fitting is performed with the flat surface facing the depth direction of the slot 32. Since the width of the slot 32 is set slightly narrower than the thickness of the optical cables 10A and 10B, when the optical cables 10A and 10B are press-fitted into the slot 32, the edge portions on both sides of the slot 32 are in a state of biting into the jackets 16A and 16B.
As a result, the edge portions on both sides of the slot 32 grip the hard tension members 14A and 14B via the jackets 16A and 16B, so that the ends of the optical cables 10A and 10B are firmly fixed to both ends of the elongated box 26. Is done. Further, since the tension members 14A and 14B exist, there is no possibility that a strong lateral pressure is applied to the optical fiber core wires 12A and 12B. When the optical cables 10A and 10B are press-fitted into the slot 32, it is preferable to press-fit the optical fiber core wires 12A and 12B with some slack.
[0014]
As shown in FIG. 3, the heat-shrinkable tube 28 is thick enough to insert the above-mentioned elongated box 26, is longer than the elongated box 26, and has a layer of a hot-melt adhesive 34 on the inner surface. This heat-shrinkable tube 28 is inserted outside one optical cable 10A or 10B before connecting the optical fiber cores 12A and 12B to connect the optical fiber cores 12A and 12B and the slots of the optical cables 10A and 10B. After the press-fitting into 32, the thin box 26 and the optical cables 10A and 10B near both ends thereof are pulled back. Thereafter, both ends (or the entire length of the heat shrinkable tube 28) are heat shrunk. Then, the hot-melt adhesive 34 on the inner surface is melted by heat at the time of heat shrinkage, and both ends of the heat shrink tube 28 are bonded and fixed to the elongated box 26 and the optical cables 10A and 10B in the vicinity of both ends as shown in FIG. The As a result, the integrity of the optical cables 10A and 10B and the elongated box 26 becomes stronger, and the strength and water tightness of the connection portion against tension can be ensured.
[0015]
Embodiment 2 FIG. 4 shows another embodiment of the present invention. In this embodiment, one optical cable 10A has a thick tension member 20 as shown in FIG. In this case, the jacket 16A is cut between the thick tension member 20 and the adjacent thin tension member 14A, and only the cable main body portion including the thin tension member 14A and the optical fiber core 12A is made the same as in the first embodiment. To the other optical cable 10B (not shown). The thick tension member 20 is used to peel off the outer cover 16 and hold the optical cable 10A on the outer wall of a house. Since the configuration other than the above is the same as that of the first embodiment, the same portions are denoted by the same reference numerals and description thereof is omitted.
[0016]
【The invention's effect】
As described above, according to the present invention, since the connection portion of the optical cable can be configured to be elongated, the installation space can be reduced. Also, after connecting the optical fiber core, the optical fiber core connection can be protected simply by press-fitting the jacket part of the optical cable into the slots at both ends of the elongated box and covering it with a heat-shrinkable tube. Easy to work. Further, since the connecting member is structurally simple, the cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of an optical cable connecting portion according to the present invention.
2 shows an elongated box used in the optical cable connection portion of FIG. 1, (A) is a plan view, (B) is a partially cutaway side view, (C) is a bottom view, (D) is a front view, E) E-E line sectional view of (B).
3 shows a heat-shrinkable tube used in the optical cable connecting portion of FIG. 1, in which (A) is a partially cutaway side view, and (B) is a sectional view taken along line BB of (A).
FIG. 4 is a cross-sectional view showing another embodiment of the optical cable connecting portion according to the present invention.
5A and 5B are cross-sectional views showing typical examples of optical cables to be connected, respectively.
[Explanation of symbols]
10A, 10B: Optical cable
12A, 12B: Optical fiber core wire
14A, 14B: Tension members
16A, 16B: Jacket
24: Optical fiber core connection
26: Narrow box
28: Heat shrinkable tube
30: Walls at both ends
32: Slot
34: Hot melt adhesive

Claims (1)

A flat optical cable connecting part covering a small number of optical fibers and a tension member,
An elongated box provided with a slot into which an optical cable is press-fitted on both end walls, and a heat-shrinkable tube having a thickness that allows insertion of the elongated box and is longer than the elongated box and having a hot melt adhesive layer on the inner surface use,
Connect the exposed optical fiber by stripping the jacket of the end of the optical cable to be connected, and cut the tension member.
The exposed optical fiber and its connecting portion are accommodated in the elongated box, and the jacket portions of both optical cables are press-fitted into the slots at both ends of the elongated box, and fixed.
Covering the elongated cable and the optical cable near its both ends with the heat shrinkable tube, heat shrinking at least both ends of the heat shrinkable tube, and adhesively fixing the elongated box and the optical cable near its both ends.
A connecting portion of an optical cable characterized by that.

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