JP3237901B2 - Iron wire armored cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an iron wire armored cable in which a hollow wire containing an optical fiber ribbon is twisted in a twisted layer of an armored iron wire.

[0002]

2. Description of the Related Art A submarine power cable and a submarine water pipe are generally in the form of an iron wire armored cable in which an outer periphery of a cable body is provided with an iron wire armor. In order to provide a communication function to the iron wire armored cable, an iron wire armored cable having a structure in which a hollow wire containing an optical fiber core is twisted together with an iron wire for armoring has been proposed (Japanese Patent Application No. Hei 1-1990). 35998).

[0003]

In the case of an iron-sheathed cable having such a structure, there is no problem if the optical fiber core housed in the hollow wire is an optical fiber core having a circular cross section. It has been found that a large increase in transmission loss occurs in the optical fiber when the optical fiber is a tape-shaped optical fiber.

Next, the result of studying the cause will be described. FIG.
Shows a conventional iron wire armored cable in which a tape-shaped optical fiber core is compounded. Reference numeral 11 denotes a power cable, which includes a conductor 13, an insulator 15, a lead sheath 17, and the like. 21 is an iron wire for armor twisted around the outer periphery of the power cable main body 11 through the seat 19, 23 is a hollow iron wire twisted together with the iron wire 21, 25
Denotes a tape-shaped optical fiber core housed in a hollow iron wire 23.

[0005] In the manufacture of this type of iron wire armored cable, it is common to twist the iron wire 21 by twisting it in order to make the twisted layer of the iron wire 21 with high rigidity difficult to collapse. For this reason, the hollow iron wire 23 twisted together with the iron wire 21 is also twisted. As a result, the tape-shaped optical fiber core 25 stored in the hollow iron wire 23
If the position shown in FIG. 5 is in the state shown in FIG.
At the position where the twist is further advanced by 90 °, the state is as shown in FIG. 7, and at the position where the twist is further advanced by 90 °, the state is as shown in FIG. That is, the tape-shaped optical fiber core 25 is formed in a spiral shape without changing the upper and lower surfaces.

However, with such a twisted structure, the tape-shaped optical fiber core 25 has a structure shown in FIG.
After being twisted, the wire housed in the hollow iron wire 23 is deformed as shown in FIG. 10, and this causes a large loss increase in the optical fibers particularly located on both sides of the tape-shaped optical fiber core wire 25. It was the cause.

[0007]

SUMMARY OF THE INVENTION The present invention provides an iron-clad armored cable which solves the above-mentioned problems. The cable comprises a power cable or a water supply pipe or the like on the outer periphery of a cable body. In an armored cable made by twisting a hollow wire containing a tape-shaped optical fiber core with an iron wire, the iron wire for the armor is twisted, and the hollow wire containing the tape-shaped optical fiber core is not twisted. It is characterized by being twisted.

[0008]

In this manner, the tape-shaped optical fiber core is formed into a spiral shape so that the tape is normally wound around the cable body, and no excessive force is applied and a large increase in loss is caused. Will not occur. In addition, since the iron wire is twisted, the armor is hardly collapsed as before.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIGS. 1 to 4 show an embodiment of the present invention, and the same parts as those in FIGS. 5 to 8 described above are denoted by the same reference numerals. The features of this iron wire armored cable are
An iron wire for armor is placed on the outer circumference of the power cable 11 via a seat 19.
Numeral 21 indicates that the hollow iron wire 23 containing the tape-shaped optical fiber core wire 25 was twisted without being twisted.

As a result, if the tape-like optical fiber 25 accommodated in the hollow iron wire 23 is in the state shown in the position of FIG. In the position where the twist is further advanced by 90 °, the state is as shown in FIG. 3 (upper and lower surfaces are inverted from those in FIG. 1). 4
(The left and right surfaces are inverted from those in FIG. 2). That is, the tape-shaped optical fiber core 25 is in the same state as when it is naturally wound around the power cable main body 11. For this reason, an excessive force is not applied to the tape-shaped optical fiber core 25, and a large increase in loss does not occur.

Although the above embodiment has described the case where the cable body is a power cable, the cable body may be a water pipe or the like.

[0012]

As described above, according to the present invention, the transmission of a tape-shaped optical fiber core in an iron-sheathed cable in which a hollow wire containing a tape-shaped optical fiber core is twisted together with an armoring iron wire. There is a very useful effect in practical use that an increase in loss can be prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view at a certain position of an iron wire armored cable according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the iron wire armored cable of FIG. 1 at a position where the twist of the iron wire armor is advanced by 90 °.

FIG. 3 is a cross-sectional view of the iron wire armored cable of FIG. 1 at a position where the twist of the iron wire armor has advanced by 180 °.

FIG. 4 is a cross-sectional view of the iron wire armored cable of FIG. 1 at a position where the twist of the iron wire armor is advanced by 270 °.

FIG. 5 is a cross-sectional view of a conventional iron wire armored cable at a certain position.

FIG. 6 is a cross-sectional view of the iron-wire armored cable of FIG. 5 at a position where twisting of the iron-wire armor is advanced by 90 °.

7 is a cross-sectional view of the iron wire armored cable of FIG. 5 at a position where the twist of the iron wire armor has advanced by 180 °.

8 is a cross-sectional view of the iron wire armored cable of FIG. 5 at a position where the twist of the iron wire armor is advanced by 270 °.

FIG. 9 is a sectional view showing a normal state of the tape-shaped optical fiber core housed in the hollow iron wire.

FIG. 10 is a cross-sectional view showing a state of a tape-shaped optical fiber core housed in a hollow iron wire in a conventional iron wire armored cable.

[Explanation of symbols]

11: Power cable 19: Seat floor 21: Iron wire for armor
23: Hollow iron wire 25: Tape-shaped optical fiber core

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-216710 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01B 11/22 H01B 7/18 H01B 7 / 00 310 G02B 6/44 361 H01B 7/22

Claims (1)

(57) [Claims] An iron wire armored cable obtained by twisting a hollow wire containing a tape-shaped optical fiber core together with an iron wire for armor around the outer periphery of a cable body such as a power cable or a water pipe. An iron-sheathed cable characterized in that a hollow wire containing a twisted, tape-shaped optical fiber core wire is twisted without being twisted.