JPS6330602B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for branching light guides in an optical cable.

After the optical cable is laid, the optical conductor may be branched to add terminals, etc. At the branching point, the cable jacket is removed and the optical conductor to be branched is taken out and connected to the optical guide for local wiring.

By the way, when connecting light guides, a connecting device is installed at a stable position near a branch point of the optical cable, and the light guides to be connected are guided to the connecting device.

In this case, in order to provide enough space to prevent unnecessary tension or bending from being applied to the light guide, an extra length is required for branching and connecting, which can be approximately 1 to 2 meters.

Therefore, when branching a light guide at the middle of an optical cable, the cable jacket must be removed for a corresponding length to provide extra length for the branch connection. In other words, the part where the cable jacket has been removed is covered with a protective body in place of the cable jacket after the branch connection work, but when a branch box is used as the protector, the shape of the branch box becomes elongated, resulting in high costs and inconvenience in handling. etc., which makes it undesirable. In addition, all the light guides of the existing optical cable are once cut, and the light guides to be branched are branched and connected there. On the other hand, in order to restore the line, an optical cable is inserted into the remaining optical fibers that have not been branched as extra connection length, and the optical fibers of the split optical cable and the optical fibers of the cut cable are connected.

According to this branch connection method, the cable sheath removal length per location can be made shorter than in the above-mentioned branch connection method.
However, since it is necessary to temporarily cut the non-branching optical conductor and connect it at two places to restore it, the number of connections increases, which not only causes deterioration of transmission characteristics but also requires a lot of effort to connect. Undesirable.

The present invention has been made in view of the above, and is capable of reducing the length of the removed portion of the cable jacket without requiring a split optical cable when branching a light guide at the middle part of an optical cable in which the light guide is housed in a removable manner. The present invention provides a method for branching a light conductor of an optical cable, which can shorten the length and facilitate branch connection work, by removing the outer jacket, etc. of the optical cable at the branch point of the light guide of the optical cable, in which the light guide is housed in a removable manner. After exposing the light guide to be branched and removing the jacket etc. of the optical cable at a position at least an extra length of light guide connection from the branch point and cutting the light guide to be branched, the light guide to be branched is cut. The extra length of the light guide is pulled back to the branch point.

Embodiments of the present invention will be described in detail below with reference to the drawings.

The drawings are explanatory diagrams for explaining a method for branching optical conductors in an optical cable according to the present invention.

In the figure, reference numeral 1 denotes an optical cable having a light guide 10, which is of a known type and has a core, a cladding layer, a protective layer, etc. in order from the center outward. Reference numeral 11 denotes a pipe made of polyamide resin or the like that accommodates the light guide 10. The light guide 10 is loosely inserted into the pipe 11 so as to have a space 12. The light guide 10 can be pulled out. Reference numeral 13 denotes a cable sheath, which is provided on the assembly of the light guides 10 and is made of a restraining layer, a metal sheath, a plastic sheath, or the like. In the above embodiment, the optical cable 1 in which the optical conductor 10 is retractably housed is shown as one in which the optical conductor 10 is loosely inserted into the pipe 11 with a space 12 therebetween. In addition to the above-mentioned optical cable 1, the present invention can be applied to any optical cable in which a light guide is retractably housed.

100 is a light guide to be branched, 100a is an extra length for connection work of the light guide 100 to be branched, and 110 is a pipe through which the light guide 100 is inserted. 2 is a branch point provided for expansion, etc., 3 is a light guide for local wiring, and 4 is a connection portion between the light guide 100 to be branched and the light guide 3 for local wiring. The light guide 100 to be branched is long, including an extra connection length 100a required for connection with the light guide 3, and in order to avoid applying excessive bending or tension to the light guides 100 and 3, the branch box 20 is It is stored in a loop.

5 is a cutting position of the light guide 100 to be branched, which is provided at a position separated by the length of the extra connection length 100a from the branch point 2, and the cable jacket 13 is removed and the light guide 100 to be branched is exposed. It will be cut off.
Reference numeral 6 denotes a sleeve provided to cover the removed portion of the cable sheath 13 after cutting the optical conductor 100 to be branched as described above in order to repair and protect the portion. 7 is a filler such as a compound provided inside the sleeve 6.

Next, the procedure for forming this embodiment will be explained.

First, the cable sheath 13 of the optical cable 1 is removed at the branching point 2, and the pipe 110 housing the light guide 100 to be branched is removed from the inner light guide 100.
Cut into rounds using a knife, etc., being careful not to damage the
110' indicates the cutting point of the pipe. Next, in order to provide an extra connection length 100a for the light guide 100 to be branched, the cable jacket 13 at a position 5, which is a distance equivalent to the extra connection length 100a from the branch point 2, is removed, and the light guide 100 to be branched is stored. The light guide 100 together with the pipe 110 is cut using a suitable cutting tool such as nippers.

The extra connection length 100a cut at position 5, which is separated by the extra connection length 100a, is pulled back at the branch point 2. The light guide 100 with the extra connection length 100a is guided to a connecting device (not shown) installed at a stable position near the branch point 2 of the optical cable 1, and connected to the light guide 3 for local wiring. Although not shown, suitable pipes can be inserted through the light guides 100a and 3 for protection. As described above, at the cutting position 5 of the optical guide 100, the removed portion of the cable sheath 13 is protected by a sleeve 6 and a known method such as a compound.

In the present invention, the length of the cable sheath that is removed in order to branch the light guide 100 and to cut the light guide 100 is extremely short, for example, about 10 to 30 cm, as is clear from the above description. good.

In addition, although the above description has been made regarding a method for branching optical conductors in an optical cable having only optical conductors, an optical cable including an electric conductor may also be used.
When the light guide is housed in a pipe as in the embodiment, it can be pulled out for quite a long time, so the light guide for wiring to the terminal device etc. can be pulled back at the branch point without connecting to the light guide for local wiring. It is also possible to cover the branched light guide with a pipe member other than the pipe described above and guide it to a location away from the branch point.

As described above, the method for branching optical conductors in optical cables according to the present invention does not require split optical cables, does not require time and effort for connection, and can shorten the cable sheath removal portion, making the work easier.
Furthermore, since there are few connection points, the transmission characteristics do not deteriorate.

[Brief explanation of the drawing]

The drawings are explanatory diagrams for explaining a method for branching optical conductors in an optical cable according to the present invention. In the figure, 1 is an optical cable, 2 is a branch point, and 5 is an optical cable.
is the cutting position of the light guide to be branched away from the branch point by the length of the extra connection; 100 is the light guide to be branched; 1
00a indicates the remaining length of the connection work of the light guide 100 to be branched.

Claims (1)

[Claims] 1. At a branch point of an optical cable in which a light guide is housed in a removable manner, the outer sheath, etc. of the optical cable is removed to expose the light guide to be branched, and at least a surplus for connecting the light guide is removed from the branch point. An optical cable characterized in that, after removing the outer sheath or the like of the optical cable at a long distance position and cutting the optical conductor to be branched, the extra length of the optical conductor to be branched is pulled back to the branching point. Light guide branching method in.