JPS609761Y2 - optical cable - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an optical cable using a vertically attached tape that is attached vertically on a cable core and wraps the cable core in a pipe shape.

BACKGROUND ART Conventionally, communication cables have been widely used, in which a cable core made up of a plurality of core wires is covered with tape longitudinally, the cable core is wrapped in a pipe shape, and an outer sheath is applied on top of the cable core.

In communication cables with this type of structure, especially in optical fiber cables, which have recently been attracting attention, it is known that when an optical fiber receives pressure (lateral pressure) from its surroundings in a direction perpendicular to its axis, the transmission characteristics, especially the transmission loss, change. As a countermeasure, a cable structure that is less susceptible to lateral pressure is required.

The conventional longitudinally attached tape and cable core described above are as shown in FIG.
The core 2 is formed into a pipe shape so that they butt against each other and surround the core 2.

A cable core using such longitudinal tape has both edges 1
There is a drawback that the abutting portions 1 and 12 are unstable, which tends to result in the situation shown in Fig. 2 (A) 9.

In other words, the butt condition is poor. In such a situation, when the presser tape is wound horizontally onto the tape 1, the tape 1 is tightened, and as a result, lateral pressure is exerted on the cable core.

Therefore, in the case of optical fiber cables, the transmission characteristics change as the cable is made, which is a bad result.

The present invention is an optical cable that eliminates these drawbacks by using a vertical splicing tape that has recesses and protrusions that engage with each other on both edges that vertically wrap and join the optical cable core.

The present invention will be explained in detail with reference to the drawings.

As shown in FIG. 3, the edge 11 of the polyethylene tape 1 is formed in a convex shape, and the edge 12 is formed in a concave shape (Figure A).

Next, a core 2 made up of a plurality of coated optical fibers is assembled.
A tape is longitudinally attached to the top so that it has a larger inner diameter than the core, and when the core is wrapped, both edges 11 and 12 are interlocked.

(frontage). Even if another presser tape is wound horizontally on top of this with a slightly stronger tension, the tape 1 will not be compressed and exert no lateral pressure on the cable core 2 because the butt portions of the tapes are interlocked.

FIG. 3 (to the figure) shows a cross section of an optical cable of the present invention using such a longitudinally attached tape, where 4 indicates a polyester holding tape and 5 indicates a plastic jacket.

In the above, the presser tape may be omitted.

The optical cable of the present invention as described above has no steps in the vertically attached tape that wraps around the cable core, so the shape of the plastic jacket is smooth, and since both edges of the tape are engaged, the shape of the tube is stabilized. Moreover, since there is a gap between the core and the tape, no lateral pressure is applied to the cable core during the cable manufacturing process, post-manufacturing installation, and maintenance, and stable transmission characteristics can be obtained.

In the present invention, the vertically attached tape 1 may be one in which a reinforcing material 3 is embedded vertically in the tape 1 as shown in FIG. Kevler fiber (trademark of DuPont, USA, aromatic polyamide), etc.), which is particularly useful in optical cables etc. because it protects the cable core from tension in the longitudinal direction of the cable core. It is.

Further, the shapes of both edges 11 and 12 of the tape 1 are not limited to the shapes shown in FIGS. 3 and 4, but may be rounded as shown in FIG. 5.

Furthermore, in the present invention, the vertically attached tape is generally easily realized when a thick plastic tape is used.

[Brief explanation of the drawing]

The drawings all show cross sections; Figure 1 is an explanatory diagram of a state in which a cable core is wrapped with a conventional vertical splicing tape, Figure 2 is an explanatory diagram of the defects that are likely to occur when using a conventional vertical splicing tape, and Figure 3 is an explanatory diagram of the state in which the cable core is wrapped with the vertically attached tape according to the present invention. Explanatory diagrams C, 4 and 5 of the optical cable of the present invention
The figures each illustrate illustrations of other examples of vertically attached tapes used in the present invention. 1...Vertical attachment tape, 2...Cable core, 5...Outer sheath.

Claims (1)

[Scope of utility model registration request] A plastic tape is attached vertically in a pipe shape on top of the cable core, which is made up of multiple coated optical fibers.
In an optical cable in which the outer periphery of the plastic tape is coated with a plastic sheath by extrusion either directly or once through a pressure-wrapping tape, the plastic tape has concave portions and convex portions provided within the tape thickness on each of both edges. An optical cable, characterized in that the plastic tapes are interlocked and attached vertically in the shape of a pipe, and that the inner diameter of the plastic tape attached vertically in the pipe shape is larger than the outer diameter of the cable core.