JPS5895302A - Manufacture of optical fiber cable - Google Patents

Abstract

PURPOSE:To protect a titled cable from external stress, by inserting an optical fiber with surplus length, into a groove of a metallic tensile force line of an H- type or that which has plural grooves in the circumference, fixing it by synthetic resin at a desired interval, and making the metallic tensile force line pass through a die. CONSTITUTION:An optical fiber 7 is inserted with surplus length, into a groove 6 of a metallic tensile strength line 5 of an H-type or that which has plural grooves 6 in the circumference. Subsequently, the optical fiber 7 is fixed so as not to move, at a prescribed interval, by use of fixing synthetic resin 8. After that, the metallic tensile force line 5 is made to pass through a die, so that the groove 6 is extrude-formed cylindrically and is closed. In this way, this cable becomes suitable for a submarine optical cable, etc. which receive strong tension. In this case, it is also possible to provide a housing on the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an optical fiber cable having a structure that protects an optical fiber and makes it difficult to transmit external tension to the optical fiber.

Optical fiber cables that are subjected to strong tension, such as conventional submarine optical cables, have a part that protects the optical fiber (optical fiber protection pipe J%), as shown in Figure 1, for example.
The optical fiber is separated into tensile strength parts (tensile strength iron wire 3, FRP, etc.) to prevent tension from being applied to the optical fiber, and these parts are covered with an outer covering. Therefore, the cable structure is complicated, the cable diameter is large, the number of manufacturing steps is increased, and the cost is increased.

In order to solve these drawbacks, the present invention manufactures an optical fiber cable by integrating a part that protects the optical fiber and a tensile strength part. The present invention will be explained in detail below with reference to the drawings.

FIG. 4 shows an embodiment of the present invention, and is a perspective view of an optical fiber cable before being passed through a die using an H-shaped metal tensile wire, and FIG. 3 is a perspective view of an optical fiber cable after being passed through a die having a circular hole. FIG. 2 is a perspective view of a fiber cable.

In FIGS. 2 and 3, on the left is a metal tensile strength wire with a plurality of grooves 6 (two in the figure) around the periphery, 7 is an optical fiber, and 7 is a synthetic resin for fixing the optical fiber.

The optical fiber cable shown in FIG. 3 is manufactured as follows.

Insert the optical fiber with extra length into the groove A of the H-shaped metal tensile strength line S in Fig. 2, and insert the optical fiber at regular intervals with synthetic resin grooves (foamed synthetic resin, a mixture of synthetic rubber and rosin modified material, etc.) for fixing the optical fiber. Fix the optical fiber back to the groove B of the metal tensile strength aS.

Next, pass the metal tensile strength wire S shown in FIG. 2 through a die with a circular hole to narrow or close the groove 6 of the metal tensile strength wire 5 - and if it is necessary to completely close the groove 6,
Electric welding is sufficient.In this case, it is necessary to cover the optical fiber 7 with a heat insulating material to prevent high heat from being applied to the optical fiber 7.This optical fiber cable is shown in FIG. The diagram does not include insulation.

The reasons for inserting the optical fiber 7 with an extra length as described above are as follows.

The first point is to prevent tension from being applied to the optical fiber bag due to the extension of the metal tensile strength wire S by passing it through a die, and the first point is to prevent the generation of stress due to tension from the outside of the optical fiber cable. This is done so that no tension is applied to the optical fiber 7. Therefore, even if a large tension is applied to the optical fiber cable, the tension is hardly applied to the optical fiber 7, and since the optical fiber protection part and the tensile strength part are integrated, the cable diameter can be reduced.

Fig. 4 shows another embodiment of the present invention, in which the metal tensile strength wire is H-shaped before being passed through the die, and the groove is U-shaped, and Fig. S shows the case in which the metal tensile strength wire is passed through the die with a circular hole. FIG. 3 is a perspective view of the optical fiber cable after it has been passed through. The symbols shown in Fig. 4 and St diagram and the manufacturing procedure of the optical fiber cable are as follows.
Since it is the same as that shown in FIG. 3 and FIG.

The optical fiber cable shown in FIG. S has the advantage that the distortion due to external force in the radial direction can be reduced compared to FIG. 3 because the hole in which the optical fiber 7 is inserted is circular.

In Figures 2 to 5 shown above, powder of a magnetizable substance (iron, ferrite, etc.) is mixed into the synthetic resin g for fixing the optical fiber, and the metal tensile strength line j is further mixed with a magnetizable substance such as steel. When the optical fiber 7 is magnetized as This can be done by simply pulling out an excess amount of the optical fiber so that it does not come out of the groove of the tensile strength wire.Another method is to take advantage of the fact that the synthetic resin for fixing the optical fiber does not harden quickly. , adding a twist to the tensile strength wire after it comes out of the die or while passing through the die.Furthermore, after the synthetic resin hardens, at least part of the amount of twist applied to the tensile strength wire is returned to give the optical fiber an extra length. Can be done・S
ru.

FIG. 6 is a cross-sectional view of another embodiment of the present invention, showing the optical fiber cable shown in FIG. 5 with a sheath added thereto, in which the tensile strength wire 3 is prevented from being scratched by an external force.

FIG. 7 shows an example of an assembled optical fiber cable in which seven optical fiber cables shown in FIG. 3 are assembled, a good electrical conductor tape 10 (copper, aluminum, etc.) is wrapped, and a jacket 9 is attached around the tape. The optical fiber cable shown in FIG. 7 has a low electrical resistance due to the attachment of the electrically conductive tape 10, and can be used as a power feeder for a long-distance relay transmission line.

As explained above, according to the method for manufacturing an optical fiber cable of the present invention, the tensile strength wire can be used to protect the optical fiber, the structure of the optical fiber cable is simple, the diameter of the optical fiber cable can be reduced, and The key is to economically produce high-strength fiber optic cables.

In the explanation of Figures 1 to 7, the tensile strength line has a number of grooves, but it is possible to increase the number of grooves. A cable with the number of optical fibers can be realized.

Further, although an example in which the cross-sectional shape of the tensile strength wire is H-shaped has been described, an E-shaped cross-sectional shape is also possible.

In order to use it as a submarine optical fiber cable, it is necessary to place tensile strength wires around the optical fiber cable shown in Figures 6 and 7, taking into account fishing obstacles, but the internal cable diameter is small. Therefore, it is possible to realize a submarine optical cable with less tensile strength wires, making it economical.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a conventional high-tensile strength (for submarine use) optical fiber cable, FIG. 2 is a perspective view of an optical fiber cable according to an embodiment of the present invention before being passed through a die, and FIG. FIG. 7 is a perspective view of the optical fiber cable after it has been passed through a die, as shown in FIG.
゛Figure 3 is a perspective view of the optical fiber cable shown in Figure 7 after passing it through the die, and Figure 6 is a perspective view of the optical fiber cable shown in Figure 7.
Figure 7 is a cross-sectional view of the optical fiber cable shown in Figure S with a sheath attached to it. FIG. 3 is a cross-sectional view of the cable. S...Metal tensile strength wire, 6...Groove, Ri...Optical fiber, T...Synthetic resin for fixing optical fiber, ? ...Outer sheath, IO...Good electrical conductor tape. Patent applicant Nippon Telegraph and Telephone Public Corporation Figure 1 Figure 2 Figure 3 Figure 4 Figure 51 Figure 6 Figure 71

Claims (1)

[Claims] 1. An optical fiber is inserted into a groove of a metal tensile strength wire having an H shape or a plurality of grooves around the circumference, with an extra length, and a synthetic resin for fixing the optical fiber is inserted into the groove at desired intervals, and the optical fiber is inserted into the groove. A method for manufacturing an optical fiber cable, which comprises fixing a fiber in a groove and passing the metal tensile wire through a die to narrow or close the groove portion containing the optical fiber. An optical fiber cable characterized in that a magnetizable substance is mixed into the synthetic resin for fixing the optical fiber, and the synthetic resin for fixing the optical fiber and the metal tensile strength wire are fixed by the adhesive force and magnetic force of the resin. Production method. 1. A method of manufacturing an optical fiber cable, which comprises covering the fiber with an electrical insulator.