JPH0756064A - Method and apparatus for production optical fiber inserted into metallic pipe - Google Patents

Abstract

PURPOSE:To provide an apparatus for producing the optical fiber inserted into a metallic pipe capable of inserting the optical fiber into the pipe simultaneously with a stage for producing the pipe and controlling a surplus length rate. CONSTITUTION:A metallic tape 1 is formed to a tubular shape in a roll forming section 6 and is welded by a welding device 7, by which the metallic pipe is formed. The optical fiber 3 is supplied through an optical fiber introducing pipe 5 into the metallic pipe under forming. The metallic pipe in which the optical fiber is housed is passed through a die device 8, by which its outside diameter is reduced. The metallic pipe is pulled in nearly a straight form by a roller type capstan 11. A metallic pipe pulling device 9 arranged between a die 8 and the roller type capstan 11 adjusts the tension on its inlet side to the tension necessary for the die device 8 and the tension on its outlet side to the tension corresponding to the elongation rate of the metallic pipe to impart the prescribed surplus length to the optical fiber, thereby imparting the prescribed surplus length to the optical fibers of the optical fiber 13 inserted into the metallic pipe.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for manufacturing an optical fiber with a metal tube in which an optical fiber is housed in a metal tube and then the outer diameter of the metal tube is dropped to manufacture an optical fiber with a metal tube. Is.

[0002]

2. Description of the Related Art Conventionally, various techniques have been developed for manufacturing an optical fiber with a metal tube, in which an optical fiber is housed in a metal tube and then the outer diameter of the metal tube is dropped to manufacture an optical fiber with a metal tube. There is.

Japanese Patent Publication No. 4-51246 discloses a method of drawing a metal pipe containing an optical fiber, in which the optical fiber is fed while welding the metal tube and the metal tube is pulled down to reduce the outer diameter. ing. To reduce the diameter, prepare a floating plug and a die with a minimum hole diameter smaller than the maximum outer diameter of the floating plug, place the floating plug in the die hole, and place the optical fiber through the optical fiber through hole of the floating plug. The diameter is reduced while pulling it through.

On the other hand, in this type of optical cable, in order to secure the reliability of optical transmission characteristics and strength, it is also possible to arrange an optical fiber with a slack in the tube, so as to provide a so-called extra length. In the method of controlling the optical fiber extra length in the cladding tube described in Japanese Patent Laid-Open No. 3-267905, the ratio of the length of the optical cable to the length of the metal tube, that is, the extra length is increased to some extent so that the optical fiber is at a high temperature or a low temperature. However, the structure is adopted so that it is not stretched or bent and a large lateral pressure is not applied. The method of giving an extra length is to stretch the metal tube formed into a tubular shape to give tension to it, and then to give vibration to the optical fiber. The tube is contracted to give an extra length to the optical fiber.

However, the method disclosed in Japanese Patent Publication No. 4-51246 cannot control the surplus length of the optical fiber in the tube. Further, as described in Japanese Patent Laid-Open No. 3-267905, in the method of manufacturing the pipe in advance,
Pipe forming by welding and insertion of optical fiber are separate processes,
In addition to low manufacturability, there is a problem that the length of the manufacturable optical fiber containing a metal tube is restricted by the distance that the optical fiber can be transmitted.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an optical fiber can be inserted into a tube at the same time as the tube manufacturing process, and the surplus ratio can be controlled. It is an object of the present invention to provide a method and an apparatus for manufacturing an optical fiber containing a metal tube.

[0007]

SUMMARY OF THE INVENTION The present invention is a method for manufacturing an optical fiber containing a metal tube by storing the optical fiber in the metal tube and then dropping the outer diameter of the metal tube. A die device for pulling down, a first metal pipe pulling device using a roller type capstan for pulling the metal pipe so that the metal pipe from the die device is kept substantially straight, the die device and the first die A second metal pipe traction device that is disposed between the second metal pipe traction device and the metal pipe is grasped from the side surface and moves substantially linearly, and the tension on the inlet side of the second metal pipe traction device is the above-mentioned. The tension required to reduce the diameter of the metal pipe in the die device is used, and the tension on the outlet side of the second metal pipe pulling device is set as the tension corresponding to the elongation amount of the metal pipe that gives a predetermined optical fiber excess length. To manufacture tubed optical fiber It is an butterfly.

After the optical fiber is housed in the metal tube,
A metal tube-containing optical fiber manufacturing apparatus for manufacturing a metal tube-containing optical fiber by pulling down the outer diameter of a metal tube, wherein a mechanism for housing the optical fiber in the metal tube and a metal tube for pulling down the outer diameter of the metal tube are provided. A die device, a second metal pipe towing device that grips the metal pipe passing through the die device from the side surface and tow it in a substantially straight line, and a roller type provided on the outlet side of the first metal pipe towing device. It is characterized in that it has a first metal pipe traction device using a capstan, and that the gripping force of the second metal pipe traction device can be adjusted.

[0009]

The inventor of the present invention has completed the present invention on the premise that the following phenomenon has been discovered and analyzed. The optical fiber housed in the metal tube comes into contact with the inner wall of the tube to generate a large frictional force in a curved tube that is wound around a roller-type capstan, resulting in a fixed state. What is possible is that the optical fiber housed in the metal tube can easily move inside the metal tube when the metal tube is straightened.On the other hand, when the metal tube is reduced in diameter by using a die, the metal tube is processed. Therefore, a very large traction force is required. In metal tubes used to house optical fibers,
This pulling force requires a force of 20 to 100 kg, and this acts as a tension on the metal pipe on the outlet side of the die.

The reason why the surplus ratio cannot be controlled by using the method disclosed in Japanese Patent Publication No. 4-51246 is that the optical fiber is fixed in a state where the metal tube is stretched by this large tension. It is considered that when the tension is released during actual use, a very large optical fiber extra length is given. In order to prevent this and to obtain an optical fiber with a metal tube with an appropriate extra length, it is necessary to apply a very large tension to the supplied optical fiber, so the mechanical strength of the optical fiber is There was a problem of being damaged.

According to the present invention, in order to pull the metal pipe, the first metal pipe pulling device using the roller type capstan is used, and the metal pipe between the first metal pipe pulling device and the die device is used. To make the movement of the optical fiber easy in this section, and at the same time, in this section, a second metal pipe pulling device for gripping the metal pipe from the side surface and moving it in a straight line and pulling it is provided. The tension on the inlet side to the tension necessary for diameter reduction in the die device, and the tension on the outlet side to give a predetermined optical fiber extra length when the tension is released. By giving it, it became possible to make the surplus length ratio to be a desired one.

That is, the die device side which requires a large tension of 20 to 100 kg, and 0 to 10 k required for winding.
The winder side, which requires a tension of about g, is separated by the second metal pipe traction device, and on this second metal pipe traction device,
By making the metal tube straight, the optical fiber is not fixed to the metal tube, the tension of the optical fiber is gradually reduced, and at the same time the elongation of the metal tube is reduced to give an appropriate extra length. Is. The extra length ratio can be adjusted by making the gripping force of the second metal pipe traction device adjustable.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic configuration diagram for explaining one embodiment of a method and an apparatus for manufacturing an optical fiber with a metal tube according to the present invention. In the figure, 1 is a metal tape, 2 is a metal tape supply, 3 is an optical fiber, 4 is an optical fiber supply, 5
Is an optical fiber introduction tube, 6 is a roll molding section, 7 is a welder,
Reference numeral 8 is a die device, 9 is a metal pipe pulling device, 10 is a tension measuring device, 11 is a roller type capstan, 12 and 13 are optical fibers containing a metal pipe, and 14 is a winder.

The metal tape 1 is supplied from the metal tape supply 2, formed into a tubular shape by a roll forming device (not shown) in the roll forming portion 6, and welded by a welder 7 with a connecting line called a seam to form a metal pipe. Become. As the material of the metal tape 1, SUS, aluminum or the like is used, but other metal materials can also be used. During this period, the optical fiber 3 supplied from the optical fiber supply 4 is supplied through the optical fiber introducing pipe 5 into the metal pipe being molded.

As described above, the metal tube containing the optical fiber is then passed through the die device 8 and the outer diameter of the metal tube is reduced to form the metal tube-containing optical fiber 12. The optical fiber 12 containing the metal tube is held in a substantially straight line from the die device 8 to the roller type capstan 11.

A metal tube traction device 9 is arranged between the die 8 and the roller type capstan 11. The metal tube pulling device 9 holds and pulls the metal tube of the optical fiber 12 containing the metal tube from both sides. In this embodiment, a belt capstan connected to a drive mechanism is used. The gripping force of the metal pipe pulling device 9 by the belt capstan can be controlled by the pressing force of the belt.

On the other hand, behind the metal pipe traction device 9, there is provided a tension measuring device 10 for measuring the tension of the metal pipe on the outlet side of the metal pipe traction device 9. The tension measuring device 10 is
A three-point tension measuring device was used. The gripping force of the metal tube traction device 9 can be adjusted by the measurement value of the tension measuring device 10. Of course, the gripping force of the metal tube traction device 9 may be automatically controlled by the output of the tension measuring device 10. By this adjustment, the tension of the metal pipe on the outlet side of the metal pipe traction device 9 can be set to a predetermined value. The optical fiber 13 containing the metal tube, which has exited the roller type capstan 11, is wound by the winder 14
The tension applied to the metal tube is released and the metal tube is shrunk at this point, so that the optical fiber of the optical fiber 13 containing the metal tube can have an extra length.

The tension applied to the metal pipe after the roller type capstan 11 can be set to the minimum level at which the metal pipe can be wound, and the winder 14 having a small torque can be used. It is possible to prevent accidents such as the optical fiber containing a metal tube bouncing after winding.

Next, a specific manufacturing example will be described.
The metal tube after welding was manufactured as a stainless steel tube having an outer diameter of 2.8 mm and a wall thickness of 0.2 mm. As the die device, five stages of existing cassette roller dies were used, and the outer diameter of the stainless steel pipe was reduced to 1.8 mm. On the other hand, a single-mode coated optical fiber having an outer diameter of 250 μm was housed inside. Here, the tension required for the above-described drop-down molding is determined by the amount of shrinkage and the sliding friction of the cassette roller die, but in this specific example, 30 kg was required.

For comparison, when the present optical fiber is supplied with a tension of 20 g and one traction device is manufactured as in the conventional case, a very large value of 0.14% is obtained as a surplus ratio of the product. It was This optical fiber with a metal tube has a loss increase of 0.6 dB / km in the 1.55 μm band at a low temperature of −40 ° C.
And the transmission characteristics were abnormal.

On the other hand, when the gripping force of the belt capstan is increased and the tension on the outlet side is increased by using the method of this specific example, the tension measured by the tension measuring device gradually decreases, When the tension was 20 kg, a product having a surplus length ratio of 0.07% was obtained, and when the tension was 10 kg, a product having a surplus length ratio of 0.03% was obtained. In each case, it was possible to obtain an optical fiber containing a metal tube, which does not cause an increase in transmission loss at -40 ° C. The relationship between the tension and the excess length ratio did not change even if the manufacturing conditions were repeatedly changed.

FIG. 2 is a schematic configuration diagram for explaining another embodiment of the manufacturing method and manufacturing apparatus for a metal tube-containing optical fiber of the present invention. In the figure, the same parts as those in FIG. 8a and 8b are dice devices.

In this embodiment, as the metal pipe pulling device 9 provided on the outlet side of the die device 8a, a driving roller whose pressing pressure can be changed by a spring mechanism is used. Further, a second dice device 8b is provided between the metal tube pulling device 9 and the roller type capstan 11 so as to give a tension capable of adjusting a predetermined optical fiber extra length. It is desirable not to increase the diameter reduction amount in the second die device 8b. Second
A metal tube pulling device may be provided between the die device 8b and the roller type capstan 11.

The winding device and the roller type capstan may be combined. However, the roller diameter changes depending on the winding amount, and the frictional force for fixing the optical fiber to the metal tube changes. Therefore, in order to stabilize the surplus length ratio, it is desirable to provide the both separately.

[0025]

As is apparent from the above description, according to the present invention, an optical fiber with a metal tube having a desired extra length ratio can be continuously and stably manufactured as a long product. The effect is that you can do it.

Further, an optical fiber containing a long metal tube can be controlled and provided so as to have a predetermined optical fiber extra length over the entire length, and in particular, an optical cable for long-distance outdoor communication in which a change in operating environment temperature is large. Is effective in the production of

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram for explaining an embodiment of a method and an apparatus for manufacturing an optical fiber with a metal tube according to the present invention.

FIG. 2 is a schematic configuration diagram for explaining another embodiment of the manufacturing method and the manufacturing apparatus for a metal tube-containing optical fiber of the present invention.

[Explanation of symbols]

 1 Metal Tape 2 Metal Tape Supply 3 Optical Fiber 4 Optical Fiber Supply 5 Optical Fiber Introducing Tube 6 Roll Forming Section 7 Welding Machine 8, 8a, 8b Die Device 9 Metal Pipe Traction Device 10 Tension Measuring Device 11 Roller Capstan 12, 13 Optical fiber with metal tube 14 Winder

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Onishi 2-48, Himegaoka, Yasakoma, Kani, Gifu Prefecture

Claims (2)

[Claims] 1. A method of manufacturing an optical fiber containing a metal tube by storing the optical fiber in the metal tube and then reducing the outer diameter of the metal tube, and a die device for reducing the outer diameter of the metal tube, and the die device. Between a first metal pipe towing device using a roller type capstan for pulling the metal pipe so that the metal pipe from the above is kept substantially straight, and the die device and the first metal pipe towing device. A second metal pipe traction device which is disposed on the side and grips the metal pipe from a side surface to move the metal pipe in a substantially straight line, and the tension on the inlet side of the second metal pipe traction device is reduced by the diameter of the metal pipe in the die device. To produce an optical fiber with a metal tube by setting the tension required for this purpose to be the tension on the outlet side of the second metal tube pulling device and the tension corresponding to the extension amount of the metal tube that gives a predetermined excess length of the optical fiber. Optical fiber with metal tube Method of manufacturing iba. 2. A metal tube-containing optical fiber manufacturing apparatus for manufacturing an optical fiber containing a metal tube by storing the optical fiber in the metal tube and then reducing the outer diameter of the metal tube. Mechanism, a die device through which the outer diameter of the metal pipe is dropped, and a metal pipe that has passed through the die device is grasped from the side surface and pulled substantially linearly.
And a first metal pipe towing device using a roller-type capstan provided on the outlet side of the first metal pipe towing device, and gripping the second metal pipe towing device. A device for manufacturing an optical fiber with a metal tube, wherein the force is adjustable.