JPS60140205A - Terminal forming method of optical fiber cable - Google Patents

Abstract

PURPOSE:To simplify and facilitate the terminal processing of an optical fiber cable by using shape memory alloy stored with a specific curling shape previously for curling operation. CONSTITUTION:When an optical fiber unit 10 is curled, a linear shape memory alloy 13 is stored with the shape which is linear at low temperature T1 deg.C and curled at high temperature T2 deg.C. Then, the linear shape memory alloy 13 is sheathed with a plastic tube 14 which becomes plastic at T2 deg.C or T2 deg.C slightly higher than it and heated up to T2 deg.C to form a spacific curling shape; and they are cooled to T1 deg.C and the shape memory alloy 13 which is linear is extracted, so that the plastic tube 14 is in the curling shape of plastic deformation by the heating. This plastic tube 14 is drawn and the excessive-length part of the optical fiber unit 10 after terminal treatment is inserted into the tube, so that the excessive-length part is stored in a repeater or pressure-tight tube in the specific curling shape.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming an end of an optical fiber cable when connecting it to a repeater, a joint box, or the like.

Due to its transmission characteristics, original fiber cables are prohibited from changing direction with extreme curvature, so in particular, when connecting repeaters installed on the ocean floor to submarine optical cables, etc., the extra connection length is required in a narrow spatial area. It is necessary to apply a complicated curling shape to the part.

Figures 1 and 2 show an example of an optical fiber unit with a complicated curling shape or customization applied to the end of the optical fiber cable, and an example of a tail cable. Optical fiber unit 10° (10A, l
0B) shows the curled shape of the extra length.

In addition, FIG. 2 shows an optical fiber unit 1 at the connection part between the repeater side 8 and the coupling side C, which have a watertight structure.
0. and the curling shape of the tail cable 11, both of which are processed in a complicated shape so that the curvature does not become smaller than a predetermined curvature in a narrow space area.

In this case, the curling of the optical fiber unit 10 is performed by the third
As shown in the figure, tension member 1. optical fiber core 2. A curled plastic tube 4 is inserted into the assembly of 3 unit fillers, and a copper tube 5 is inserted into the tail cable 11 as shown in FIG. and polyethylene 6
Curl 1 row 5 by bending the coated material.
It is something.

Conventionally, in the terminal processing of such original fiber cable,
In the optical fiber unit 100 curling process, a skilled worker manually curls a nylon tube into an appropriate shape and uses a dryer. After heating and forming the nylon tube, the deformed nylon tube was stretched by hand, and then the optical fiber unit 1
Inserting 0.

Therefore, there is a problem in that the curling shape slightly differs depending on the work.

Further, in the curling work of the tail cable 11, the tail cable 11 is directly bent manually, so there is also a problem in that the curled shape varies depending on the work.

Therefore, it has been considered to use jigs for these forming operations, but it is especially important to use jigs for parts that have complex shapes, such as the part O shown in Figures 1 and 2. It is difficult to do this, and it is also difficult to use jigs when working on site.

This invention was made in view of the actual situation,
The present invention provides a method for simplifying the terminal processing of optical fiber cables by using a shape memory alloy.

Hereinafter, the optical fiber cable terminal forming method of the present invention will be explained.

In recent years, shape memory alloys 2 for which applied technology has been developed in various fields, such as Ti and Ni alloys, have a unique property called shape memory effect.

This is because an alloy that initially remembers a specific shape undergoes star-like deformation beyond its elastic limit, but it completely recovers to its original memorized shape by heating or cooling.
A unidirectional shape memory alloy having only a high temperature R state point t, and an omnidirectional (bidirectional) shape memory alloy having two shapes at a low temperature transformation point and a high temperature transformation point have been developed.

This invention utilizes the shape memory effect of such a shape memory alloy to form the end of the optical fiber cable described above. First, the case of curling the optical fiber unit 10 is shown in FIG. ) to (d).

For the linear bidirectional shape memory alloy 13, FIG.
), a linear shape is stored at a low temperature transformation point (T, °C), and a curled shape as shown in FIG. 1 is stored at a high temperature transformation point (T, 'C). Next, the high temperature transformation point (T
, 2°C) The support should be prepared with a plastic tube 14 that becomes plastic at a slightly higher point (T,°C) as shown in Figure 5(b).
), and then it is inserted into the shape memory alloy 13, which has become straight at low temperature, as shown in FIG. 5(c). Thereafter, when it is heated to a high temperature transformation point (T, "C) using a dryer or the like, it becomes the predetermined curling state that was initially stored, as shown in FIG. 5(d).

Then, when it is further cooled to the low temperature transformation point (T, "C), it returns to the state shown in FIG. It returns to the curled shape when it was plastically deformed by heating (Fig. 5e).

Therefore, the plastic tube 14 having a predetermined curled shape is stretched, and the original fiber unit 10 is terminated as shown in FIG. 1 or 2.
When the extra length of the optical fiber unit 10 is inserted through the extra length of the optical fiber unit 10, the extra length of the optical fiber unit 10 forms a predetermined curling shape and is connected to the repeater.
Alternatively, it can be stored in a pressure-resistant tube.

In this case, the fifth phase after returning to the low temperature transformation point (TloC)
The shape memory alloy 13 may be formed into a curled shape by inserting it into the extra length of the optical fiber unit 10 and removing only the shape memory alloy 13 in the state shown in Figure (C). Also, Fig. 5 (C) after returning to the low temperature transformation point (T, “C)
In this case, the optical fiber unit 10 may be connected to one end of the shape memory alloy 13 as shown by the dotted line, and drawn into the plastic tube 14 to be formed into a predetermined curled shape.

In addition, since it is easy to return the state shown in FIG. 5(d) to the straight state shown in FIG. 5(c) manually, a unidirectional shape memory alloy 13 may also be used. I can do it.

Next, the tail cable 1 in which the copper tube etc. are nuclided
The molding method No. 1 will be explained with reference to FIGS. 6(a) to 6(d).

Since the tail cable 11 has relatively high rigidity, the following J5 molding method is preferable.

First, it is linear at the low temperature transformation point (T, “C), and the high temperature transformation point (
A shape memory alloy 15 (FIG. 6(a)) is prepared in which a predetermined curling shape is memorized at , T, and ``C''.

Next, the straight shape memory alloy 15 is overflowed onto the part of the tail cable 11 that has been terminally processed to be curled, and several parts are bound with wires 16, etc., as shown in FIG. 6(b). or wrap them together with strong adhesive tape.

The tail cable is then heated to a high temperature transformation point (T, ``C) using a hair dryer, etc., and the tail cable is forcibly bent at 11V.
Make a trap curling shape as shown in c). Thereafter, when the bind or adhesive tape is released and the shape memory alloy 15Y is removed, the tail cable 11 is formed into a predetermined curled shape as shown in FIG. 6(d).

In the method of forming the tail cable 11, the stress required for plastic deformation 1 due to the coated copper tube is large (therefore, it is necessary to use a thick shape memory alloy that has a large shape recovery force).

Furthermore, as shown in FIG. 6(e), if a part of the cross section of the shape memory alloy 1-5 is made flat or concave, and a cable is bound over the flat or concave surface, the repeater The curling direction for the connection can also be in any desired direction.

The high temperature transformation point (T, °C) of shape memory alloy 13.15 is 1
Since products with temperatures below 00°C are commercially available, the optical fiber core 2 is almost never damaged.

As explained above, in the optical fiber cable terminal forming method 5 of the present invention, the curling operation is performed using a shape memory alloy in which a predetermined curling shape is memorized in advance, so the curling operation is extremely easy. This has the advantage that it can be carried out without special engineers.

Furthermore, since the curling shape is made uniform by the shape memory alloy, it can be expected that variations in the transmission characteristics of the optical fiber cable will be reduced.

[Brief explanation of drawings]

Figures 1 and 2 are side views showing an example of curling the extra length of the optical fiber unit or tail cable as a terminal treatment for optical fiber cables, Figure 3 is a cross-sectional view of the optical fiber unit, and Figure 1M4 is the tail Cross-sectional view of the cable,
FIGS. 5(a) to 5(e) are explanatory diagrams of a method for forming an extra length of an optical fiber unit, and FIGS. 6(a) to (e) are explanatory diagrams of a method of forming an extra length of a tail cable. Figure A, 10.1OA, 10B are optical fiber units, 1
1 is the tail cable, 13.15 is the shape Figure 2 Figure 5 Figure 3

Claims (2)

[Claims] (1) A thermoplastic plastic tube is inserted into a shape memory alloy that assumes a predetermined shape at a high temperature transformation point, and then heated to the high temperature transformation point, and the thermoplastic plastic tube formed into a predetermined shape is exposed to light. A method for forming an end of an optical fiber cable, the method comprising inserting the fiber unit F into the extra length thereof and forming the optical fiber unit F into a predetermined shape. (2) A shape memory alloy that assumes a predetermined shape at a high temperature transformation point,
A method for forming an end of an optical fiber cable, characterized in that the tail cable is formed into the predetermined shape by fixing the extra length 'tG of the tail cable and heating it to the temperature of the high temperature transformation point.