JPS6318161B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a boot for a joint box of optical submarine cables used for mechanically and optically connecting optical submarine cables to each other.

In the optical submarine cable system, an example of mechanically and optically connecting optical submarine cables to each other is repair work performed onboard a ship when a cable failure occurs. The transmission medium of an optical submarine cable is an optical fiber whose main component is quartz, which is a brittle material, and it is important to avoid stretching or bending it as much as possible. Further, for optical connection of optical fibers to each other, optical fiber core wires of several tens of centimeters to about 1 meter are required on both sides of the connection part as an extra length for the connection work. This connection must be accommodated without any tension and protected from the high water pressure at the seabed. Such requirements are
This is a problem that did not exist in the cable interconnection of conventional submarine coaxial cable systems, and can be said to be a problem unique to optical submarine cable systems that use optical fibers.

In order to meet this requirement, it is conceivable to house the connection part and the extra connection length in a pressure-resistant container similar to the optical submarine repeater case. However, since the casing only accommodates the interconnecting parts of the optical fibers and their extra length, it is desirable that the casing be as small as possible, and the internal space of the pressure-resistant cylinder is limited to the diameter.
It is thought to be about 10cm long with an axial length of around 15cm.
In addition, considering the cable retention part for mutually transmitting cable tension, the length of the rigid part of the housing is 50 mm.
The outer diameter is around 15 cm, and this is usually called the joint box of an optical submarine cable. With such a small casing, there is a possibility that it can be adapted to the drum-shaped laying mechanism of a cable laying ship without using the gimbaled universal joint used in the repeater casing. Furthermore, a structure without gimbal joints reduces costs and is economical.
On the other hand, if there are no gimbal joints on both sides of the casing, the optical submarine cable may bend locally at the end of the rigid part of the casing, causing transmission loss. It is important to know how smoothly it can be wrapped around the drum surface.

Figure 1 is for explaining the outline of a case where an optical submarine repeater housing with a gimbal joint is wound on a cable drum surface. 1 shows the curved surface of the cable drum, and 2 shows the optical submarine repeater housing. A pressure-resistant cylinder, 3 a universal joint called a gimbal, 4 a cable coupling housing, 5 a boot insert, 6 a rubber part of the boot, and 7 an optical submarine cable. The rigid part of the optical submarine repeater housing (corresponding to the length L between two gimbal pins) is approximately 1.5 m long, but the cable does not bend locally due to the gimbal bending around 50 degrees. It wraps around the drum surface without causing any transmission loss.

FIG. 2 is for explaining the boot of the optical submarine cable coupling shown in FIG. 1, where 5 is a boot insert, 6 is a rubber part of the boot, and 9 is a protector 8 fixed to the cable coupling housing 4 shown in FIG. It shows the threaded part to be screwed to the part called. Therefore, since the left side of C in the figure is continuously rigidly connected to the cable coupling housing 4, it is assumed that even if a load -P in the Z direction is applied, it will not be displaced and bent in the Z direction. good. On the other hand, since there is only the rubber part 6 of the boot on the right side of C, it is expected that local bending will occur at C, which is the end of the rigid part.

FIG. 3 is a schematic diagram of the boot shown in FIG. 2 fixed to both sides of a joint box of an optical submarine cable whose schematic structure is shown by a metal cylinder 10 and a protector 8, and wound around a drum curved surface 1. 5 is a boot insert, 6 is a rubber part of the boot, 7 is an optical submarine cable, 8 is a protector fixed with a threaded part 11 of a metal cylinder 10 called a protective cover, and 9 is a fixing of the boot insert 5 to the protector 8 The threaded part is shown. The boot insert 5 is embedded inside the boot when the rubber part 6 is made, so there is good adhesion between the boot rubber part 6 and the boot insert 5, and there is no peeling except for C' at the end of the rigid part. It is thought that this will not occur. However, in a joint box with such a boot structure, as the cable tension increases as it passes through the drum curved surface, the cable suddenly bends, or buckles, at the end of the rigid part of the C' section, and eventually breaks the cable. There is a fear. This is because the bending rigidity of the boot insert itself is significantly different from that of the rubber part of the boot and the cable.

The object of the present invention is to use a boot insert that can be fixed to a protector with a flexible structure so that the boot insert itself is slightly bent, so that optical submarine cables and joint boxes for optical submarine cables can be wrapped around the curved surface of the drum easily. An object of the present invention is to provide a boot for a joint box for an optical submarine cable, which can be used in a joint box for an optical submarine cable.

The present invention will be explained in detail below using the drawings.

Figures 4a and 4b show a boot structure for explaining one embodiment of the present invention, and Figure 5 shows a boot structure for explaining a case where the joint box of an optical submarine cable is wound around a cable drum using this boot. It is something. FIG. 4b is a sectional view taken along line AA in FIG. 4a. In the embodiment shown in FIG. 4, 5, 5a, and 5b constitute a boot insert, and the second rigid ring 5a is connected to the insert body ring (first rigid ring) 5 by the wire rod 5b. connected to.
6 is a rubber part of the boot, 9 is a threaded part for fixing the ring 5 to the protector 8, and 12 is a wire 5b attached to the 5
13 indicates a threaded section for fixing the wire 5b to the ring 5a, 14 indicates a nut, and 15 relieves bending stress near the threaded section 12 even when the wire 5b is bent. It is an escape section for doing things. A cable 7 is passed through the ring 5 of the first rigid structure and the ring 5a of the second rigid structure, and the wire 5b is arranged so as to surround the cable. The boot insert of the present invention has a portion 5 fixed to the protector 8 with a rigid structure and through which the submarine cable passes;
Since it is composed of a ring 5a having a rigid structure and a ring 5a having a rigid structure fixed by a wire rod 5b which is a flexible structure, it can withstand external forces perpendicular to the axis that act when winding the cable onto the cable drum surface 1. Since the cable 5b of the flexible structure is present, the cable does not bend excessively at the c' end, and the cable bends without excessively bending near the ring 5a of the second net structure. is smoothly wound around the drum as shown in Figure 5. The length of the wire can be as short as 10 cm or less since the boot insert only needs to be bent slightly, and the thickness of each wire is around 10 mm, so the boot insert itself is not very large. Further, the material of the wire 5b may be the same as that of the rings 5, 5a.

As described above, the joint box for optical submarine cables has a boot insert inside which connects a ring-shaped rigid structure with a slightly bendable wire rod, and the joint box can be wound around the cable drum easily. . Although this example has been explained with a drum-type installation mechanism in mind, if it is compatible with the drum-type, it can also be used as a boot for joint boxes of optical submarine cables, which can also be compatible with caterpillar-type and tire-type linear cable engines. I can do that.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view showing a conventional optical submarine cable connected to an optical submarine repeater housing using a gimbal joint and wound around a cable drum.
Figure 3 is a longitudinal sectional view for explaining the cable coupling boot used in the conventional example of Figure 2.
FIGS. 4a and 4b are longitudinal sectional views and transverse sectional views showing embodiments of the present invention; FIGS. 5 is a longitudinal sectional view showing a state in which an optical submarine cable joint box using a boot according to the present invention is wound around a cable drum. 1... Curved surface of cable drum, 2... Pressure-resistant cylinder of optical submarine repeater housing, 3... Universal joint, 4... Cable coupling housing, 5... Boot insert (first rigid structure ring), 5a... Second rigid structure ring, 5b... Wire rod, 6... Rubber part of boot, 7... Optical submarine cable, 8... Protector, 9... Threaded part, 10... Metal cylinder, 1
1, 12, 13...Screw, 14...Nut, 15
...Escape club.

Claims (1)

[Claims] 1. In a boot for a joint box of an optical submarine cable, which is fixed to both sides of the joint box of the optical submarine cable and used to protect the connection part of the optical submarine cable with the joint box, one end of the joint box a ring of a first rigid structure fixed to and through which the submarine cable passes; and a ring of the first rigid structure so as to surround the optical submarine cable that has passed through the ring of the first rigid structure. The boot insert includes a plurality of wire rods having a flexible structure and a ring having a second rigid structure attached to the free end side of the wire rods. A joint box for an optical submarine cable, characterized in that the boot insert is embedded in a rubber material so that it can be bent without excessive bending due to the elastic force of the rubber boot around it. boots.