JPH0452723Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] The present invention not only allows easy insertion of tape-shaped optical fiber cores into slots during manufacturing, but also avoids applying excessive force to the core wires and reduces construction work. The present invention relates to a slot type optical cable whose core wires can be easily taken out.

[Conventional technology and its problems]

Although optical fiber cables have excellent transmission characteristics compared to metal cables, they have problems in terms of strength, and various reinforcement measures have been taken.

On the other hand, in order to facilitate the identification and sorting of optical fibers, optical fibers are arranged in the length direction on a tape-shaped optical fiber or a sheet-like film, and the optical fibers are arranged in a grid-like manner. Wound fiber optic cables have been proposed, but all of these cables have problems in terms of tensile strength.

Therefore, a slot type optical cable was proposed as a cable that allows easy identification and sorting of core wires and has high mechanical strength such as tensile strength and lateral pressure. As shown in FIG. 9, this cable has a rod D made of an elastic material such as plastic having a tension member 1 in the center, and a slot 2 consisting of a spiral groove formed in the longitudinal direction of the outer surface of the rod D. One or more tape-shaped optical fiber cores a are stacked and inserted into the core, and a sheath is provided around the outer periphery.

However, traditional slot-type cables
As shown in the figure, the slot 2 has a U-shaped cross section. For this reason, the optical fiber core a must be inserted into it so that its width direction is lateral (tangential to the circumferential direction) and its length direction is spiral.
The closer it is to the bottom of the slot 2, the more difficult it is to insert it smoothly, and depending on the tension or guidance on the optical fiber core a, the optical fiber core a may become vertical or diagonal as shown in Figure 10. Problems may occur.

In addition, when connecting optical fiber core a during installation,
Since the core wires a are stacked horizontally in the deep slot 2 having a U-shaped cross section, it is not a problem to take out the core wires from the top, but it becomes more difficult to take them out from the bottom, resulting in poor workability.

Furthermore, if a bending force is applied to this cable during or after installation, for example, in FIG. However, since the bending direction of the upper and lower optical fiber core wires a is in the width direction, it is difficult to follow the bending, and there is a high risk of breakage.

[Purpose of invention]

In view of the above points, the present invention enables easy and reliable insertion of the tape-shaped optical fiber core without applying excessive force to the core during the process of inserting the core, and during and after installation. The purpose of this invention is to reduce the risk of damage to the core wires and to facilitate the removal and sorting of the core wires when connecting the core wires during installation work.

[Means for achieving the purpose of the invention]

In order to achieve the above object, in the slot type optical cable of the present invention, a tension member is arranged in the center and a groove of a plastic rod is spirally provided with a groove having a V-shaped cross section on the outer periphery. The structure is such that one or more optical fiber tapes are inserted along the inclined surface of the optical fiber.

[Effect]

In the slot-type optical cable according to the present invention constructed in this way, the tape-shaped optical fiber core wire is inserted along the slope of the V-groove, so it can move freely along the slope and is easy to insert. It is something. In addition, even if a bending force is applied to the cable during or after installation, the bending force will be applied to the cable due to the movement of the core wire along the inclined surface of the V-groove and movement in the circumferential direction of the rod within the V-groove. (see Figure 1).

〔Example〕

Next, one embodiment of the present invention will be described according to its manufacturing procedure.

First, the center tension member 1 is made of galvanized steel strands, and the galvanized steel strands are transferred to the nipple holder 2 of the extrusion molding machine A shown in FIG.
The material is then passed through the nipple 22 and through the center of the die 23, and the resin b is extruded around its outer periphery to obtain a round bar-shaped rod material D'.

This rod material D' is passed through the slot forming machine B shown in FIG. Six cutting blades 33a with a triangular cross section are provided at equal intervals on the inner surface, and the die 33 is made of a rod material.
When D' is inserted and pulled out, the die 33 is rotated by the pulling force and the slot 2 is cut by the cutting blade 33a to obtain the rod D shown in FIG. On this occasion,
The dice 33 may be rotated by other power depending on the take-up speed.

The cutting edge 33a is inclined corresponding to the helical direction of the slot 2, and the degree of inclination is different from that of the slot 2.
It is determined by the value obtained by dividing the diameter of the slot by the pitch of the slot 2. Therefore, as shown in FIG. 4, as in the well-known screw die, the degree of inclination of the cutting edge 33a increases from the trough b to the top t.

The rod D manufactured in this way is introduced into a cage rotating type twisting machine shown in FIG. Insert multiple sheets side by side. That is, as shown in FIG. 5, the rod D is fed out from the supply stand 10 and the straightening roll 1
1, passes through the hollow shaft of the twisting machine 12, and passes through the die 1.
3, the 18 tape-shaped optical fiber cores a from the twisting machine 12 are inserted into the six slots 2 in a stack of three in the optical fiber core insertion section 14 in the middle of the process. A cable core 15 shown in FIG. 1 is obtained. This cable core 15 is wound onto a take-up stand 17 through a taping machine 20, a dancer roller 16, etc.

In this manufacturing process, as shown in Figure 6,
A support frame 18 is coaxially protruded from the hollow shaft 12a of the wire stranding machine 12, and the stranding machine 1
Guide roller 19 for optical fiber core a from 2
is provided. This guide roller 19 is arranged so that each optical fiber core wire a is inserted in an overlapping manner along the inclined surface 2a of the slot 2,
As a result, each optical fiber core a is inserted into slot 2.
It is inserted smoothly into the inside.

When the optical fiber core a is inserted in a spiral manner, a force in the width direction is applied to the core fiber a, causing it to rotate or stand up. However, if it is inserted obliquely as in this example, The degree of resistance to force in the width direction is small, and the position of the guide roller 19 can be determined easily.

In addition, even if the core wire a is twisted, the
The twist is absorbed by the movement of the core wire a along the slope of the slot 2, shown by the chain line, and the movement within the slot 2, as shown in b in the figure, and the core wire a is smoothly inserted into the slot 2. . This movement of the core wire a in the slot 2 is also carried out in the same way when bending force is applied to the cable, and the bending force is absorbed.

In the above embodiment, the slot 2 is cut by cutting.
However, the slot 2 can also be formed simultaneously with the extrusion molding of the rod material D'. That is,
In the extrusion molding machine A shown in FIG. 2, FIG.
As shown in FIG. 8, the inner surface of the die 23 has a cross section 3.
Six square projections 23a are provided at equal intervals, and during extrusion molding, the die 23 is rotated by the motor 24 via a pinion 25 and a gear 26 integrated with the die 23, forming a V-shaped cross section on the outer periphery of the rod D. The grooves are formed in a spiral shape. That is, the slot 2 shown in FIG. 1 is formed. The rotation speed of the die 23 is determined by dividing the take-up speed of the rod D (extrusion speed of the resin b) by the helical pitch of the slot 2. Furthermore, the protrusion 23a is inclined in accordance with the helical direction of the slot 2, similar to the cutting blade 33a.

[Effect of idea]

As can be understood from the above explanation, the present invention is
Since the slot has a V-shaped cross section and the optical fiber is inserted into the slot along the inclined surface, the manufacturability of the rod and the workability of inserting the optical fiber are improved.

Furthermore, when connecting the optical fibers during installation, the optical fibers can be easily guided along the inclined surface of the slot, resulting in good workability.

Furthermore, since the optical fiber core can move freely within the slot, there is less risk of damage to the core due to bending of the cable or the like.

[Brief explanation of the drawing]

Fig. 1 is a partial cross-sectional view of one embodiment of the slot-type optical cable according to the present invention, a and b are diagrams of its working modes, and Figs. 2 and 3 are cross-sectional views for explaining the rod manufacturing of the same embodiment. Figure 4 is an explanatory diagram of the shape of the cutting blade in Figure 3, Figure 5 is a schematic diagram for explaining the manufacturing of the above embodiment, Figure 6 is a perspective view of the main part of Figure 5, Figures 7 and 8. The figures are a schematic sectional view and a partially cutaway right side view of another manufacturing example of the rod, FIG. 9 is a partial sectional view of the conventional example, and FIG. 10 is an explanatory view of the working part of the conventional example. D... Rod, a... Optical fiber core, 2...
...Slot, 2a... Inclined surface, 19... Guide roller, 23, 33... Dice, 33a... Cutting blade.

Claims (1)

[Scope of utility model registration request] A tension member is placed in the center and the cross section is V on the outer periphery.
A slot type characterized in that one or more tape-shaped optical fiber cores are inserted into the groove of a rod made of plastic having spiral grooves along the inclined surface of the groove. optical cable.