JPS6230639A - Production of core fiber for pipe-type optical fiber - Google Patents

Abstract

PURPOSE:To obtain the titled core fiber having high longitudinal uniformity and longer length than the sheath, easily, by coating an optical fiber with an anti-adhesion agent, extrusion-coating the optical fiber with a pipe to hold the fiber in loose state, taking up the coated product under cooling, removing the applied tension and heating the product. CONSTITUTION:A pipe-type optical fiber core 4 consisting of a pipe 1 and an optical fiber 3 having equal length to the pipe 1 is produced by a conventional extrusion coating apparatus devoid of a braking device 10. Concretely, the fiber 3 is unwound from the bobbin 5, coated (5) with an anti-adhesion agent 2, and extrusion-coated (7) with the pipe 1 which can hold the fiber 3 in loose state. The extrusion-coated fiber is taken up with a take-up capstan 9 under cooling (8) and wound up with a winding bobbin 11, etc. The tension applied to the core fiber 4 during the winding is removed, the core fiber 4 is introduced into the heating apparatus 12, and the pipe 1 is heated and annealed to remove the residual strain generated in the production process, and allowed to shrink. Accordingly, the length of the pipe 1 becomes shorter than the fiber 3 to form the objective pipe-type optical fiber core containing the optical fiber 3 having longer length than the pipe 1 and meandering in the pipe 1.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to the manufacture of a pipe-shaped optical fiber core, in which optical fibers are housed loosely and with extra length in the pipe via an anti-adhesive agent such as oil. It is about the method.

[Prior art]

Conventionally, as shown in FIG. 3, one or more optical fibers 3 are loosely inserted into a pipe 1 made of plastic such as polyethylene or polyvinyl chloride through an anti-adhesive agent 2 such as oil. A pipe-shaped optical fiber core 4 is known that is housed with extra length by meandering or the like. By the way, the pipe-shaped optical fiber core wire 4 has the effect of protecting the optical fiber 3 from external force by loosely covering the pipe 1, and the effect of making the optical fiber 3 meander within the pipe 1. By giving extra length to the optical fiber 3, even if a tensile force is applied to this core wire, the force will be received by the pipe 1 for a while and the load will not be applied to the optical fiber 3.
It has a kind of effect.

The anti-adhesion agent 2 is used to prevent the pipe 1 and the optical fiber 3 from adhering when the pipe 1 is coated by extrusion.

Now, as a method for manufacturing the above-mentioned pipe-shaped optical fiber core 4, the method described in Japanese Patent Publication No. 5B-29481 is generally used.

This method will be explained with reference to FIG. First, the optical fiber 3 is supplied by the optical fiber bobbin 5, and while the anti-adhesion agent 3 is applied thereto by the anti-adhesion agent application device 6, the optical fiber 3 is loosened (stored) by the extrusion coating a7.
That is, the optical fiber 3 is covered with a plastic pipe 1 having an inner diameter larger than the outer diameter. Thereafter, it is cooled in a cooling tank 8, taken up by a take-up capstan 9, and wound up on a winding machine via an accumulator (not shown) or the like. Here, the feature of this method is that a brake device 10 is provided between the cooling tank 8 and the take-up capstan 9 as shown in FIG. Tension is applied to the core wire 4 to stretch only the pipe 1, and then this pipe-shaped optical fiber core wire 4 is stretched.
After passing through the take-off capstan 9, the purpose is to remove the tension.

In this way, only the pipe 1 is pulled between the brake device 10 and the take-up capstan 9, and the lengths of the pipe 1 and the optical fiber 3 are made to match at this point, and after passing through the take-up capstan 9, the tension is removed. By doing so, only the pipe 1 is contracted, and as a result, the length of the optical fiber 3 inside the pipe 1 is made longer, that is, the extra length of the optical fiber 3 is maintained.

However, in this method, if the cross-sectional area of the pipe 1 is small, the braking force by the brake device IO will be a very small value, but in that case, since it is very small, it is difficult to adjust, and the pipe shape It becomes difficult to apply a uniform braking force to the optical fiber core wire 4 in the longitudinal direction.

[Purpose of the invention]

In view of the above-mentioned problems, an object of the present invention is to provide a method that can extremely easily manufacture a pipe-shaped optical fiber core having a uniform extra length in the longitudinal direction.

[Structure of the invention]

In order to achieve the above object, the method of the present invention includes extrusion coating one or more optical fibers coated with an anti-adhesion agent in advance with a pipe that loosely accommodates the one or more optical fibers; Then, when the pipe-shaped optical fiber core wire is produced by taking it while cooling it, the tension applied to the pipe-type optical fiber core wire is removed, and the pipe is heated to contract the pipe. It is characterized by

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below with reference to the drawings.

In the present invention, first, in FIG.
A pipe-shaped optical fiber core wire 4 in which the optical fiber 3 has no extra length with respect to the pipe 1 is manufactured using a so-called existing extrusion coating apparatus without a pipe 1. That is, the optical fiber 3 is supplied by the optical fiber bobbin 5 around which the optical fiber 3 is wound,
An anti-adhesive agent 2 such as oil is applied to this by an anti-adhesive agent application device 6.
to prevent the optical fiber 3 from adhering to the pipe 1 during extrusion coating of the pipe 1, which will be described later, and then loosely store the optical fiber 3 with the anti-adhesion agent 2 in the optical fiber 3 with the anti-adhesion agent 2. extrusion coating machine 7
Cover with This is taken up by a take-up capstan 9 while being cooled by a cooling tank 8 such as a water tank, and wound onto a take-up bobbin or a take-up drum by a take-up machine via an akinemulator or the like (not shown). Note that packets may be taken without being wound onto a bobbin or the like. In this state, the optical fiber 3
is the same length as pipe 1 and has no extra length. Next, the tension applied during take-up and winding is removed from the pipe-shaped optical fiber core wire 4 wound onto the winding bobbin or drum.

For example, when the fiber is wound onto the winding bobbin 11, the collar 12 of the winding bobbin 11 is removed as shown in FIG.
Just take them out and make them into a bundle as shown in Figure 2. Of course, if you take the bucket, you can do it as shown in Figure 2 from the beginning, which is preferable. That is, in this case, the tension applied by the take-up capstan 9 is immediately removed after passing through the take-up capstan 9.

Once the tension applied during manufacture is released from the pipe-type optical fiber core wire 4, it is then placed in a heating device 12 such as a heating chamber, and if the pipe 1 is made of polyethylene or nylon, for example, the tension applied during manufacturing is released. The pipe 1 is annealed by heating at about 80°C, or about 120'C in the case of polypropylene, to remove residual strain from manufacturing, or to promote recrystallization of the resin, resulting in to contract. Therefore, the length of the pipe 1 becomes shorter than the optical fiber 3, and at this time, due to contact friction between the inner surface of the pipe 1 and the outer surface of the optical fiber 3, the optical fiber 3 becomes shorter than the pipe 1.
The extra length is added by meandering within.

In the above embodiment, an example was shown in which only one optical fiber 3 was housed in the pipe 1, but the same applies to the case where a plurality of optical fibers 3 are housed. The temperature at which the pipe 1 is heated varies depending on the material of the pipe 1, but in any case, it must be at a temperature that removes the residual strain in the pipe 1 and causes the resin to recrystallize, but at the same time the temperature must be such that the resin starts to melt. It goes without saying that even high temperatures should not be used. Furthermore, by controlling the heating temperature within the above-mentioned temperature range, it is also possible to control the amount of contraction of the pipe 1, thereby controlling the extra length of the optical fiber 3.

In this way, in the present invention, unlike the conventional method of controlling the extra length by the braking force of the brake device, even if the cross-sectional area of the pipe l is small, the pipe type has a uniform extra length in the longitudinal direction of the core wire. Optical fiber core wires can be manufactured extremely easily. Furthermore, although a separate heating device is required, the existing extrusion device can be used as is.

That is, in the past, if there was no space for installing the brake device in the existing extrusion =ri, it was sometimes necessary to rearrange the entire extrusion device.

〔Effect of the invention〕

As described above, according to the present invention, even when the cross-sectional area of the pipe is small, it is possible to extremely easily manufacture a pipe-shaped optical fiber core in which the remaining length of the optical fiber is uniform in the longitudinal direction of the core wire.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the tension removing method according to the present invention, FIG. 2 is a perspective view showing an embodiment of the present invention, and FIG.
The figure is a perspective view of a pipe-type optical fiber core, and FIG. 4 is a schematic diagram showing a conventional method for manufacturing a pipe-type optical fiber core. 1 - Pipe 2 - Anti-adhesion agent 3 - Optical fiber
4 - Pipe type optical fiber core wire 6 - Anti-adhesion agent coating device 7 - Extrusion coating machine 12 - Heating device Fig. 1 Fig. 2 Fig. 3 Fig. 4

Claims (1)

[Claims] One or more optical fibers that have been coated with an anti-adhesive agent in advance are extruded with a pipe that loosely accommodates the one or more optical fibers, and this is taken out while cooling to produce a pipe-shaped optical fiber. A method for manufacturing a pipe-shaped optical fiber core, which comprises manufacturing a core, then removing tension applied to the pipe-type optical fiber core, and heating the core to shrink the pipe. .