JP3181550B2 - Method and apparatus for manufacturing optical fiber coated with metal tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing method and a manufacturing apparatus for continuously manufacturing an optical fiber cable coated with a metal tube, and more particularly to an optical fiber for removing dust and the like adhering to an optical fiber cable and inserting the same into a metal tube. The present invention relates to protection of a cable and improvement in accuracy of control of extra length of an optical fiber.

[0002]

2. Description of the Related Art In order to secure the laying tension and water resistance of an optical fiber cable, a metal tube coated optical fiber cable in which an optical fiber cable is coated with a thin metal tube is used. Apparatuses for continuously manufacturing this metal tube-coated optical fiber cable are disclosed in, for example, JP-A-58-95304 and JP-A-57-95304.
No. 100402, and the like. The apparatus for manufacturing metal-coated fiber optic cables forms a continuous, fed flat metal strip into a metal tube having a longitudinal gap at the top. An introduction tube is inserted into the metal tube through the gap between the metal tubes, and the optical fiber is introduced into the metal tube by the introduction tube. After closing the gap between the metal tubes into which the optical fibers have been introduced, the butt portion is welded to a laser welding device or the like. Thereafter, the outer diameter of the metal tube containing the optical fiber cable is reduced to a predetermined size, and then wound around a capstan and continuously drawn to produce a metal tube-coated optical fiber cable. When the metal tube-coated optical fiber cable is manufactured in this manner, the introduction pipe is extended to a downstream side downstream from the welded portion to prevent the heat of welding from damaging the optical fiber.

The optical fiber used for the metal tube-coated optical fiber cable usually has a core wire coated with an ultraviolet curing resin, and static electricity is easily generated, so that dust in the air tends to adhere. If the optical fiber to which the dust adheres is passed through the introduction pipe as it is, dust remains in the introduction pipe during a long-term operation, and an extra backward tension is applied to the optical fiber. In particular, when the metal tube is filled with a gel or the like which is a viscous substance, dust adhering to the optical fiber is mixed into the gel and easily adheres and deposits on the tube wall of the introduction tube. Therefore, the tension of the optical fiber adjusted before inserting the introduction tube fluctuates in order to control the excess length of the optical fiber, and the excess length of the optical fiber cannot be controlled, so that a long metal tube-coated optical fiber cable cannot be used. It was difficult to manufacture.

In order to solve this problem, a method of manufacturing a metal tube-coated optical fiber cable by a clean room is disclosed in, for example, Japanese Patent Application Laid-Open No. Sho 57-123838 (Japanese Patent Publication No. 59-23838).
No. 3414). In this method, the core wire of an optical fiber drawn in a vacuum atmosphere is subjected to primary coating in the atmosphere, and then the metal tube is welded to the optical fiber by immediately introducing the optical fiber into the metal tube in a vacuum atmosphere. It prevents dust from adhering.

[0005]

As shown in the above-mentioned Japanese Patent Application Laid-Open No. 58-95304, when an optical fiber is introduced simply by using an introduction tube inserted into a metal tube, a butt portion at the lower portion of the metal tube is used. There is no particular problem when joining by brazing, but when welding the butted portion on the upper part of the metal pipe by TIG welding or laser welding to seal the metal pipe,
The welding spatter was deposited on the inlet pipe, and if the welding spatter was operated for a long time, the deposited welding spatter could come into contact with the inner wall of the metal pipe to cause poor welding. For this reason, in particular, there is a disadvantage that a long metal tube-coated optical fiber having a length of 5 km or more cannot be continuously manufactured.

In addition, since the introduction pipe is only inserted into the metal pipe and is not particularly positioned, the distance between the introduction pipe and the welding surface of the metal pipe sometimes becomes very small due to vibration of the metal pipe during traveling. turn into. In such a case, TI
There was also a danger that the heat of G welding or laser welding would cause burnout on the upper surface of the inlet pipe, resulting in a hole, causing thermal damage to the optical fiber passing through the inside or burning the gel.

Further, as disclosed in Japanese Patent Application Laid-Open No. Sho 57-123838, a method of manufacturing a metal tube-coated optical fiber cable using a clean room is a method in which dust in the air adheres to the optical fiber. Can be prevented. However, in the forming process of the metal tube, a duct or the like is generated from the brush of the motor of the drive mechanism and adheres to the optical fiber, and this dust is mixed into the gel and adheres and accumulates on the tube wall of the introduction tube. Stay longer in the tube. Since dust remaining in the introduction tube cannot be removed, an extra backward tension is given to the optical fiber, and the extra length, that is, the length of the optical fiber with respect to the length of the metal tube, is adjusted to each tension. In the case of controlling by the method, there is a disadvantage that it is difficult to uniformly produce the same quality, particularly a long product.

[0008] This disadvantage can be solved by blocking only the optical fiber passage with a clean gas curtain, but the opening at the boundary with the metal tube forming device is large, and outside air is entrained, and dust is introduced into the optical fiber. It was difficult to completely prevent the adhesion. In addition, each time the metal pipe forming apparatus is adjusted due to the curtain structure, airflow is turbulent, dust is likely to adhere to the optical fiber, and the adjusting operation of the forming apparatus is hindered.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned disadvantages, and it is intended to prevent dust from remaining in an introduction pipe and to surely protect the introduction pipe and optical fibers from welding heat of a metal pipe. It is another object of the present invention to provide a method and apparatus for manufacturing a metal tube-coated optical fiber that can be operated stably for a long time.

[0010]

A method of manufacturing a metal tube-coated optical fiber according to the present invention comprises forming a metal strip,
In a method for manufacturing a metal tube-coated optical fiber for introducing an optical fiber or an optical fiber bundle into a metal tube formed by welding a butt portion, a guide tube for guiding the optical fiber or the optical fiber bundle and either a gas or a filler. Or an optical fiber or an optical fiber bundle connected to a supply pipe that supplies both, and a straight pipe-type introduction pipe inserted into a metal pipe,
One or both either gas or filling Ri sent to the metal tube, metal tube introduced an optical fiber or optical fiber bundle
The metal tube and optical fiber at the entrance of the capstan
Make the fiber or optical fiber bundle have a different tension
Capstan for tension between tube and optical fiber or optical fiber bundle
The metal tube and light on the exit side of the capstan
To give a difference in elongation of fiber or optical fiber bundle
And controlling the extra length of the optical fiber or the optical fiber bundle .

Another method for manufacturing a metal tube-coated optical fiber according to the present invention is to form an optical fiber or an optical fiber bundle into a metal tube formed by forming a metal strip and welding a butt portion. In the manufacturing method of
An optical fiber or an optical fiber bundle is introduced into a straight tube-type introduction tube comprising a double tube consisting of an optical fiber introduction tube inserted into a metal tube and a filler introduction tube covering the optical fiber introduction tube. Ri feed the metal tube through a tube, also the optical fiber
Is a cap around which a metal tube with an optical fiber bundle is wound
Metal tube and optical fiber or optical fiber at the entry side of the tongue
Give a difference in the tension of the bundle, and
Reduce the tension of the fiber bundle with the capstan and
The metal tube and optical fiber or optical fiber on the exit side of the stan
By giving a difference in the amount of elongation of the bundle, the optical fiber or optical fiber
Control the extra length of fiber bundle . A gas is preferably sent from the optical fiber introduction tube together with the optical fiber or the optical fiber bundle.

It is preferable to use an inert gas or a cooling gas as the above gas. Also, it is preferable to use a waterproof material as the filler.

An apparatus for manufacturing a metal tube-coated optical fiber according to the present invention is for manufacturing a metal tube-coated optical fiber for introducing an optical fiber or an optical fiber bundle into a metal tube formed by forming a metal strip and welding a butt portion. In the apparatus, a guide tube for guiding an optical fiber or an optical fiber bundle, a supply tube for supplying one or both of a gas and a filler, and an optical fiber or an optical fiber bundle and a gas or a filler inserted into a metal tube. either one or the e Bei and a connecting portion for connecting the supply pipe and inlet pipe and inlet pipe and the guide tube straight tube type to be sent to the metal tube both optical fiber or optical fibers of the
The entrance side of the capstan where the metal tube with the bundle is wound
The tension between the metal tube and the optical fiber or optical fiber bundle at
Make a difference between the metal tube and the optical fiber or optical fiber bundle.
Of the capstan by reducing the tension of
Of the metal tube and optical fiber or optical fiber bundle on the side
The difference in the amount of the optical fiber or optical fiber bundle
It is characterized in that the extra length is controlled .

Another apparatus for manufacturing a metal tube-coated optical fiber according to the present invention is a metal tube-coated optical fiber for introducing an optical fiber or an optical fiber bundle into a metal tube formed by forming a metal strip and welding a butt portion. Production equipment,
A straight pipe that is inserted into the metal pipe and has a double pipe consisting of an optical fiber feed pipe for sending an optical fiber or a bundle of optical fibers into the metal pipe and a filler feed pipe for covering the optical fiber feed pipe and feeding the filler into the metal pipe. Has a tube-type introduction tube, optical fiber or
Capster around which a metal tube with an optical fiber bundle is wound
Tube and optical fiber or optical fiber bundle at the entry side
Between the metal tube and the optical fiber or optical fiber.
Reduce the tension of the fiber bundle with the capstan and
Metal tube and optical fiber or optical fiber at the exit side of the tongue
By providing a difference in the amount of elongation of the bundle,
It is characterized in that the excess length of the bundle is controlled .

The above-mentioned introduction pipe is pressed against the inner wall of the metal pipe at the welded portion opposite to the welded surface of the metal pipe, so that the distance from the welded surface is reduced.
It is preferable to keep at a position where the separation is always maximum .

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a straight pipe-type introduction pipe inserted into a metal pipe is used to send an optical fiber or a bundle of optical fibers and one or both of a gas and a filler into the metal pipe. The dust adhering to the surface of the optical fiber or the bundle of optical fibers is purged from the entrance of the guide tube by causing a part of the gas or the filling to overflow from the entrance of the guide tube for guiding the optical fiber or the bundle of optical fibers.

At the welded portion of the metal tube, the introduction tube is inserted and fixed so as to be pressed against the inner wall of the metal tube on the side opposite to the welding surface. , The introduction pipe is always located on the side opposite to the welding surface, and the distance between the introduction pipe and the welding surface is always kept constant.

Further, light passes through a straight-tube-type introduction tube composed of a double tube consisting of an optical fiber introduction tube inserted into a metal tube and a filler introduction tube covering the optical fiber introduction tube. Sending the filler from the filler introduction tube into the metal tube while sending the fiber or optical fiber bundle into the metal tube,
The optical fiber or the optical fiber bundle is prevented from being affected by the viscous resistance of the filler when passing through the introduction tube, and is inserted into the metal tube while maintaining a constant tension.

[0019]

FIG. 1 is a sectional view showing an embodiment of the present invention. As shown in the figure, an optical fiber introducing device 1 includes a guide tube 3 for guiding an optical fiber or an optical fiber bundle (hereinafter, referred to as an optical fiber) 2, a supply tube 5 for supplying a cooling gas 4, and a straight tube. It has an introduction pipe 6 and a guide pipe 3, a supply pipe 5, and an introduction pipe connection fitting 7 connecting the introduction pipe 6. The communication hole 8 of the introduction pipe connecting fitting 7 with the guide pipe 3 is provided in the introduction pipe 6.
Has a smaller inner diameter than the communication hole 9. The introduction tube 6 is formed of copper or a copper alloy having good heat conductivity, and is inserted into a metal tube 10 covering the optical fiber 2.

The metal tube 10 is formed by molding a continuously fed metal strip 10a. That is, the metal strip 10a fed via the pinch roll 11 is formed into a substantially U-shape while being raised from below by a break-down forming roll 12 which is arranged at an inclination.
3 to the forming roll 14. Both ends of a substantially U-shaped metal strip 10b are butted by a forming roll 14, and the butted portion is welded by a laser welding device 15 to form a metal tube 10. The introduction pipe 6 is inserted at the position of the metal strip 10b formed in a substantially U-shape, and a downward pressing force is applied to the introduction pipe 6 by the pressurizing mechanism 16, so that the metal on the opposite side to the welding surface 17 is formed. The tube 10 is pressed against and fixed to the inner wall of the tube 10.

The metal tube 10 continuously fed as described above
2, the tension of the optical fiber 2 is adjusted by a dancer roll 21 provided at the preceding stage of the optical fiber introducing device 1 as shown in FIG. Is sent to the metal tube 10 while being guided by the guide tube 3 and the introduction tube 6. At the same time, the cooling gas 4 is continuously supplied from the supply pipe 4 at a constant pressure. Then, the butted portion of the metal tube 10 is welded by the laser welding device 15. This metal tube 10
Is welded to the inner wall of the metal tube 10 on the side opposite to the welding surface 17 when the butt surfaces of the metal tubes 10 are welded, the metal tube 10 is continuously formed and fed. Therefore, even if vibration occurs, the introduction pipe 6 can always be located on the side opposite to the welding surface 17, and the distance between the introduction pipe 6 and the welding surface can always be kept constant. Therefore, the introduction pipe 6 and the optical fiber 2 guided by the introduction pipe 6
Can reduce the thermal influence of welding. Further, the cooling pipe 4 continuously supplied from the supply pipe 4 cools the introduction pipe 6 and the optical fiber 2 in the vicinity of the welded portion, so that the thermal effect of welding can be further reduced. Although the case where the butt portion of the metal tube 10 is laser-welded has been described, the thermal effect of welding can be similarly reduced when welding is performed by TIG welding or the like.

Further, the introduction pipe 6 is pressed against the inner wall opposite to the welding surface 17 so that its position does not move and the distance from the welding surface can always be kept at a maximum. Even if welding spatter is deposited on the upper surface, it does not come into contact with the metal tube 10 and can be operated for a long time.

The metal tube 10 containing the optical fiber 2 with the butted portion welded thereto is reduced in diameter to a predetermined diameter by the drawing means 22 and sent to the capstan 23. The tension between the metal tube 10 and the optical fiber 2 on the entrance side of the capstan 23 is made different, and the tension between the metal tube 10 and the optical fiber 2 is reduced by the capstan 23 so that the metal tube on the exit side of the capstan 23 is reduced. The difference between the length of the optical fiber 10 and that of the optical fiber 2 is provided to control the surplus length. The metal-fiber-coated optical fiber cable 25 whose surplus length is controlled is wound around a winder 27 through a dancer roll stand 26.

When the metal tube-coated optical fiber cable 25 is manufactured in this way, the optical fiber 2 sent to the guide tube 3 has the dust in the air remaining on the surface coating. Then, a part of the cooling gas 4 supplied from the supply pipe 5 is sent to the inlet side of the guide pipe 3 through the communication hole 8 with the guide pipe 3 of the inlet pipe connection fitting 7 and is ejected from the inlet of the guide pipe 3. By the ejection of the cooling gas 4, dust adhering to the coating surface of the optical fiber 2 is removed to the outside. Therefore, no dust adheres to the optical fiber 2 entering the introduction tube 6, and dust adheres to the inner wall of the introduction tube 6.
Accumulation and remaining in the pipe can be prevented.

Although the above embodiment has been described with reference to the case where the cooling gas 4 is supplied from the supply pipe 5, the welding portion is protected by supplying an inert gas, and the introduction pipe 6 and the optical fiber 2 are cooled. In addition, dust attached to the optical fiber 2 can be eliminated. Further, even when a filler for waterproofing is supplied from the supply pipe 5 to fill the metal pipe 10 and a part of the filler overflows from the entrance of the guide pipe 3, the same operation as in the above-described embodiment is obtained. Can play.

Although the above embodiment has been described with respect to the case of using a single-tube introduction tube, as shown in FIG. 3, an optical-fiber introduction tube 51 through which the optical fiber 2 passes, and an optical-fiber introduction tube An introduction pipe 53 composed of a double pipe of a filling introduction pipe 52 covering the filler 51 may be used. Then, the guide pipe 3 is connected to the gas supply pipe 41 and the optical fiber introduction pipe 51 by the introduction pipe connection fitting 7, and the supply pipe 5 for supplying the filler and the filler introduction pipe 52 are connected to each other. While introducing the optical fiber 2 and a cooling gas or an inert gas or the like into the metal tube 10 by the fiber introduction pipe 51, dust adhering to the surface of the optical fiber 2 by a part of the gas can be eliminated. In this case, the filler supplied from the supply pipe 5 is sent into the metal pipe 10 through the space between the optical fiber introduction pipe 51 and the filler introduction pipe 52, so that the optical fiber 2 passes through the thin introduction pipe. The optical fiber can be inserted into the metal tube 10 while maintaining a constant tension without being affected by the viscous resistance of the filler, and the extra length of the optical fiber controlled by the capstan 23 can be controlled with high precision. You can also. Further, even if a large pressure is applied to the filler, the filler does not leak from the guide tube 3 of the optical fiber 2, and the yield of the filler can be improved.

In the embodiment shown in FIG. 3, the case where the gas supply pipe 41 is connected to the introduction pipe connection fitting 7 has been described. However, as shown in FIG.
Are connected, the same operation as the above embodiment can be achieved.

Although the above embodiment has been described with reference to the case of using the straight pipe-type introduction pipe 6, an introduction pipe which is curved in a substantially L-shape with a constant curvature may be used.

FIG. 5 shows an introduction pipe 61 curved substantially in an L-shape.
Here is an example in the case of using. As shown in the figure, a curved introduction pipe 61 is connected to the guide pipe 3 and the supply pipe 5 by an introduction pipe connection fitting 7, and while the optical fiber 2 is sent from the vertically arranged guide pipe 3, the supply pipe 5 is used for cooling or cooling. Supply gas for purging or gel which is a packing for waterproofing. The optical fiber 2 and gas are introduced into the metal tube 1 through the introduction tube 61.
When the gas was introduced into the container, a part of the gas was ejected from the inlet side of the guide tube 3 or the filling material was caused to overflow into the container 31 so that the gas adhered to the surface of the optical fiber 2 sent to the guide tube 3. Dust can be removed. The filling material overflowing in the container 31 is collected by the suction pipe 32.

When the introduction pipe 61 which is curved in a substantially L-shape with a constant curvature as described above is used, when the introduction pipe 61 is inserted into the metal pipe 10, the entire introduction pipe 61 is pressed downward.
When the elastic force of the curved portion bent at a constant curvature is used, the introduction pipe 61 is placed near the welded portion on the inner wall opposite to the welded surface of the metal tube 10 without the need for a pressurizing mechanism for applying a downward pressing force. Can be pressed against.

Further, in each of the above embodiments, the case where the gas or the filler is separately supplied from the supply pipe 5 has been described. However, the gas and the filler can be supplied simultaneously. For example, as shown in FIG. 6, a gas introduction joint 43 to which a gas supply pipe 42 is connected is provided above a guide pipe 3 a having an overflow hole 41 of the filling material. Then, while sending the optical fiber 2 to the curved introduction pipe 61 through the gas introduction joint 43 and the guide pipe 3a, a gel as a waterproofing filler is supplied from the supply pipe 5 and sent into the metal pipe 10 through the introduction pipe 61. . The gas is supplied from the gas supply pipe 42 while overflowing a part of the filler from the overflow hole 41 of the guide pipe 3a, and the optical fiber 2
Is injected from the inlet of the gas introduction joint 43 into which the gas is introduced. By simultaneously supplying the gas and the filler as described above, after dust adhering to the optical fiber 2 is removed by jetting out the gas, the remaining dust can be further removed by overflow of the filler. Dust can be more reliably prevented from entering.

Further, in each of the above embodiments, the case where the introduction tube 61 made of a single tube is used has been described. However, as shown in FIG.
Alternatively, an introduction tube 63 composed of a double tube of a filling tube 62 for covering the optical fiber introduction tube 61 may be used.
Then, the guide pipe 3 and the gas supply pipe 4 are connected by the introduction pipe connection fitting 7.
2 and the introduction pipe 61 for optical fiber, and the supply pipe 5 for supplying the filler and the introduction pipe 62 for the filler are connected, so that the optical fiber 2 and the cooling gas or the non- While introducing an active gas or the like into the metal tube 10,
Dust adhered to the surface of the optical fiber 2 by a part of the gas can be eliminated. In this case, the filler supplied from the supply pipe 5 is divided into an optical fiber introduction pipe 61 and a filler introduction pipe 6.
The optical fiber 2 is fed into the metal tube 10 through the space between the two tubes, and is not affected by the viscous resistance of the filler when the optical fiber 2 passes through the thin inlet tube. It can be inserted, and the extra length of the optical fiber can be controlled with high precision.

In the embodiment shown in FIG. 7, the case where the gas supply pipe 42 is connected to the introduction pipe connecting fitting 7 has been described. However, as shown in FIG.
Are connected, the same operation as the above embodiment can be achieved.

[0034]

According to the present invention, as described above, the optical fiber
Key around which a metal tube into which a fiber bundle or optical fiber bundle is introduced is wound.
Metal tube and optical fiber or optical fiber at the entry side of the capstan
Give the fiber bundle a difference in tension, and
Or reduce the tension of the optical fiber bundle with a capstan,
Metal tube and optical fiber or light at the exit side of the capstan
By giving a difference in the elongation of the fiber bundle,
By controlling the extra length of the optical fiber bundle,
The excess length of the bus can be controlled with high precision. In addition, a straight pipe-type introduction pipe inserted into the metal pipe, while sending one or both of the optical fiber or the optical fiber bundle and the gas or the filler into the metal pipe, illuminates a part of the gas or the filler. The dust adhering to the surface of the optical fiber or the optical fiber bundle is purged from the guide tube entrance by overflowing from the entrance of the guide tube for guiding the fiber or the optical fiber bundle. Since it can be prevented from remaining in the introduction pipe, the optical fiber can be smoothly passed through the introduction pipe even after long operation. Further, since no dust remains in the introduction pipe, no extra backward tension is applied to the optical fiber passing through the introduction pipe, and the extra length of the optical fiber can be controlled with high accuracy.

In the welded portion of the metal tube, the introduction tube is inserted and fixed so as to be pressed against the inner wall of the metal tube on the side opposite to the welding surface. Even if the occurrence occurs, the introduction pipe is always located on the side opposite to the welding surface, so that the distance between the introduction pipe and the welding surface can always be kept constant and guided by the introduction pipe and the introduction pipe. The thermal effect of welding on the optical fiber and the filler can be reduced, and damage due to heat can be reliably prevented.

Further, an optical fiber or an optical fiber is passed through an optical fiber introducing tube of a double tube consisting of an optical fiber introducing tube inserted into a metal tube and a filler introducing tube covering the optical fiber introducing tube. By feeding the filler into the metal pipe from the filler introduction pipe while feeding the bundle into the metal pipe, the optical fiber or the optical fiber bundle is prevented from being affected by the viscous drag of the filler when passing through the introduction pipe, The optical fiber can be inserted into the metal tube while maintaining a constant tension, and the extra length of the optical fiber can be accurately controlled without applying extra backward tension to the optical fiber passing through the introduction tube.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is an overall configuration diagram of the embodiment.

FIG. 3 is a sectional view showing a second embodiment of the present invention.

FIG. 4 is a sectional view showing a third embodiment of the present invention.

FIG. 5 is a sectional view showing a fourth embodiment of the present invention.

FIG. 6 is a sectional view showing a fifth embodiment of the present invention.

FIG. 7 is a sectional view showing a sixth embodiment of the present invention.

FIG. 8 is a sectional view showing a seventh embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 optical fiber introduction device 2 optical fiber 3 guide tube 5 supply tube 6 introduction tube 7 introduction tube connection fitting 10 metal tube 51 introduction tube for optical fiber 52 introduction tube for filling 53 introduction tube

Continuation of the front page (72) Inventor Yuji Matsuoka 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Inventor Nobuyuki Yonezawa 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Inventor Isamu Komine 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Inventor Nozomi 1-1-2, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Invention Person Kazunari Inoguchi 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Inventor Yasunori Yoshie 1-1-2, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (56) References JP 58-95304 (JP, A) JP-A-57-100402 (JP, A) JP-A-61-17447 (JP, A) JP-B-62-47606 (JP, B2) (58) Fields investigated (Int .Cl. ⁷ , DB name) G02B 6/44

Claims (11)

(57) [Claims] 1. A method of manufacturing a metal tube-coated optical fiber, comprising: introducing an optical fiber or an optical fiber bundle into a metal tube formed by forming a metal strip and welding a butt portion.
An optical fiber or an optical fiber is connected to a guide tube for guiding an optical fiber or an optical fiber bundle and a supply tube for supplying one or both of a gas and a filler, and is connected to a straight tube-type introduction tube inserted into a metal tube. and flux, one or both either gas or filling Ri sent to the metal tube, the light-off
Metal tube with fiber or optical fiber bundle wound
Metal tube and optical fiber or light at the entrance of the capstan
Give a difference in the tension of the fiber bundle, and
Reduce the tension of the fiber or fiber optic bundle with the capstan.
And the metal tube and optical fiber or
Optical fiber bundles by providing a difference in the amount of expansion of the optical fiber bundle.
A method for manufacturing a metal tube-coated optical fiber, comprising controlling an excess length of a fiber or an optical fiber bundle . 2. A method of manufacturing an optical fiber coated with a metal tube, comprising introducing an optical fiber or an optical fiber bundle into a metal tube formed by forming a metal strip and welding a butt portion,
An optical fiber introducing pipe of a straight pipe introducing pipe comprising an optical fiber or an optical fiber bundle, and a double pipe consisting of an optical fiber introducing pipe inserted into a metal pipe and a filler introducing pipe covering the optical fiber introducing pipe. feeding the metal tube through Ri, optical fiber or
Capster around which a metal tube with an optical fiber bundle is wound
Tube and optical fiber or optical fiber bundle at the entry side
Between the metal tube and the optical fiber or optical fiber.
Reduce the tension of the fiber bundle with the capstan and
Metal tube and optical fiber or optical fiber at the exit side of the tongue
By providing a difference in the amount of elongation of the bundle,
A method for manufacturing a metal tube-coated optical fiber, characterized by controlling an extra length of an iba bundle . 3. The method according to claim 2, wherein a gas is sent from the optical fiber introduction tube together with the optical fiber or the optical fiber bundle. 4. The method according to claim 1, wherein the gas is an inert gas. 5. The method according to claim 1, wherein the gas is a cooling gas. 6. The method for producing a metal tube-coated optical fiber according to claim 1, wherein said filler is a waterproof material. 7. The distance between the introduction pipe and a welding surface of a metal pipe.
Is always held at the position where the maximum value is obtained .
7. The method for producing a metal tube-coated optical fiber according to 4, 5, or 6. 8. An apparatus for manufacturing an optical fiber coated with a metal tube, wherein an optical fiber or an optical fiber bundle is introduced into a metal tube formed by forming a metal strip continuously fed and welding a butt portion. A guide tube for guiding a fiber bundle, a supply tube for supplying one or both of gas and filling, and a metal tube inserted into the metal tube to connect the optical fiber or optical fiber bundle and one or both of gas and filling. Bei example a connecting portion for connecting the supply pipe and inlet pipe and inlet pipe and the guide tube straight tube type to be sent to the metal tube, light
A metal tube into which a fiber or optical fiber bundle is introduced is wound
Metal tube and optical fiber at the entry side of the capstan
Give a difference in the tension of the optical fiber bundle, and
Reduce the tension of the fiber or fiber bundle with the capstan.
And the metal tube and optical fiber or
Optical fiber bundles by providing a difference in the amount of expansion of the optical fiber bundle.
An apparatus for manufacturing a metal tube-coated optical fiber, characterized by controlling an excess length of a fiber or an optical fiber bundle . 9. An apparatus for manufacturing an optical fiber coated with a metal tube for introducing an optical fiber or an optical fiber bundle into a metal tube formed by forming a metal strip and welding a butt portion,
A straight pipe that is inserted into the metal pipe and has a double pipe consisting of an optical fiber feed pipe for sending an optical fiber or a bundle of optical fibers into the metal pipe and a filler feed pipe for covering the optical fiber feed pipe and feeding the filler into the metal pipe. e Bei a tubular inlet tube, an optical fiber or
Capster around which a metal tube with an optical fiber bundle is wound
Tube and optical fiber or optical fiber bundle at the entry side
Between the metal tube and the optical fiber or optical fiber.
Reduce the tension of the fiber bundle with the capstan and
Metal tube and optical fiber or optical fiber at the exit side of the tongue
By providing a difference in the amount of elongation of the bundle,
An apparatus for manufacturing a metal tube-coated optical fiber, characterized by controlling a surplus length of a fiber bundle . 10. The method according to claim 9, wherein a gas is sent from the optical fiber introduction tube together with the optical fiber or the optical fiber bundle. 11. The distance between the introduction pipe and a welding surface of a metal pipe.
The apparatus for producing a metal tube-coated optical fiber according to claim 8, 9 or 10, wherein the apparatus is held at a position where the separation is maximized .