JPS6025762B2 - Submarine optical cable bending protector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a structure in which a submarine optical cable is connected to a submarine optical repeater weight body or a submarine optical cable connection box, and when the submarine optical cable near the base or the subsequent box receives a severe bending force, the optical cable This invention relates to a submarine optical cable bending protector designed to prevent damage to the functional performance, etc. of submarine optical cables.

FIG. 1 is an overall schematic diagram of the submerged submarine coaxial repeater body.

In this Figure 1, numeral 1 is a submarine coaxial cable, 2 is a rubber boot, 3 is a gimbal connection, 4 is a bellows, and 5 is a rubber boot.
is a pressure-resistant body. FIG. 2 is a detailed structural drawing of the area around the boot No. 2 in FIG. 1. In FIG. 2, reference numeral 6 indicates a cable retaining portion crab body, and numeral 7 indicates a cable pulling crab portion. As shown in FIG. 2, the second rubber boot is made of conical homogeneous rubber, and a cylindrical hole having the same outer diameter as the submarine coaxial cable is passed through the center of the cone. In general, in a structure in which a submarine coaxial repeater weight body or cable connection box with a large diameter is simply connected to a submarine coaxial cable with a small diameter, there is a connection between the submarine coaxial repeater weight body or cable connection box and the pupil body or the connection box near the submarine coaxial cable. If the submarine coaxial cable did not have the boot 2 shown in FIGS. 1 and 2, the vicinity of the connection between the two would be discontinuous in size and structure, and the strength against bending force would be low. For this reason, the structure shown in Figures 1 and 2 is equipped with a rubber foot 2 to prevent the submarine coaxial cable from being bent beyond the allowable curvature due to severe bending force. This allows the connecting part to travel smoothly in the desired direction without any hindrance. By the way, in order to connect a submarine optical cable to a submarine optical repeater weight body and prevent damage to the submarine optical cable from severe bending force at the cable connection part under severe installation work environment conditions, the above-mentioned conventional method is required. The boot design method that has been applied to submarine coaxial cables is considered difficult to apply.

FIG. 3 is a diagram showing approximate values of the dimensional structure and bending rigidity of a known submarine coaxial cable and submarine optical cable.

The bending rigidity shown in the figure is based on the Young's modulus E and section modulus 1 of the material.
The greater the bending rigidity, the more the columnar body resists bending. From this figure 3, the amount of bending stiffness of submarine optical cable is approximately 1/1 of that of submarine coaxial cable.
It is clear that it is low and easy to bend. (If the two types of cables shown in the figure are cantilevered and the same load is applied to the tip, the amount of deflection (6) at the tip of the submarine optical cable is approximately one fold of the amount of deflection (6) at the tip of the submarine coaxial cable. ) For this reason, when connecting a submarine optical cable to a submarine optical repeater body or connection box, the submarine optical cable near the submarine optical repeater body or connection box must be wound on a drum during cable transportation. It is necessary to prevent damage to the cable's function from the severe bending forces generated during work processes such as installation and installation work. The present invention has been made in view of the above circumstances, and an object thereof is to provide a submarine optical cable bending protector capable of protecting a submarine optical cable from severe bending force. Alternatively, a protection body is attached around the submarine optical cable in the vicinity of the submarine optical cable connection box, taking into consideration the mechanical strength, shape, and permissible curvature of the cable.

Examples of the present invention will be described below.

FIG. 4 shows an embodiment of the present invention, in which 1 is a submarine optical cable, 2 is a rubber boot, 3 is a gimbal, 4 is a bellows, 5 is a pressure pupil body, 6 is a cable retaining body, and 7a is a cable. Crab part, 7b is polyethylene mold, 8a, 8b
is a cable bending protector that is harder than rubber.

In 8a and 8b, the outer fleas are gradually made thinner and the mechanical strength is lowered so that the tip portion of the cable protector has the same diameter as the submarine optical cable.

Further, the lengths (li) of 8a and 8b are gradually increased. The structural design of the cable bending protector shown in FIG.
Regarding the allowable curvature y of the submarine optical cable 1, R8a>R8
The relationship b>R≠y is applied, and the relationship L8a<L8b is applied to the length La of the portion 8a and the length Lb of the portion 8b.
With this configuration, the mechanical strength is reduced in the order of the cable bending protector 8a, the cable bending protector 8b, and the tip of the cable bending protector. By the above-described design method, it is possible to protect the function and damage of the submarine optical cable from severe bending force applied to the vicinity of the cable anchoring portion. FIG. 5 shows the state of bending of the tip of the cable pulling part in the case where the cable pulling part of the submarine optical repeater body is constructed using the conventional cable holding part structure Yoshihan Ju method. FIG. 6 shows a case in which a cable retaining portion is constructed according to the present invention. As explained above, in the submarine optical cable connection part attached to both ends of the submarine optical repeater crab body or the submarine optical cable connection box, the mechanical strength of the cable bending protector from the connection part to the tip of the boot is gradually reduced, Since the cable bending protector has a structure in which the permissible curvature at the tip matches the permissible curvature of the submarine optical cable, it is possible to use a drum-type laying machine or a bow seag of a laying ship during the installation work process to avoid damage to the seabed at the tip of the cable connection. This has the advantage of preventing the optical cable from becoming smaller beyond its permissible curvature and preventing damage to the submarine optical cable.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the sub-bottom submarine coaxial repeater screen, Figure 2 is a diagram showing details of the structure around the boot in Figure 1, and Figure 3 is a diagram showing dimensions of known submarine coaxial cables and submarine optical cables. Figure 4 is a diagram showing the structure and approximate values of bending rigidity, Figure 4 is a diagram showing an embodiment of the present invention, and Figure 5 is a diagram showing the case where the conventional submarine coaxial cable cable drag crab protection technology is applied to a submarine optical cable as is. FIG. 6 is a conceptual diagram of the bending of the cable tip when the present invention is applied to a cable retaining part of a submarine optical cable. 1... Submarine optical cable, 2... Foots, 3
・・・・・・．・Gimbal, 4... Bellows, 5・
...Pressure resistant lotus body, 6...Cable retention part bell body, 7a...Cable retention part, 7b...Polyethylene mold, 8a, 8b...Cable bending protector . Figure 5 Figure 6

Claims (1)

[Claims] 1. At the submarine optical cable connection part that connects the submarine optical repeater housing or the submarine optical cable connection box and the submarine optical cable and protects the vicinity of these connection points from external forces, the area around the submarine optical cable from the connection point to the tip of the connection part. The mechanical strength of a cable bending protector made of at least two layers of material attached along the cable is gradually reduced, and the protector is made smaller in diameter, so that the allowable curvature at its tip matches the allowable curvature of the submarine optical cable. A submarine optical cable bending protector characterized by: