JP2002333559A - Optical fiber unit and its pressure transport method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber unit which makes the insertion by pressurized air flow into the pipe easier and which exhibits excellent force-feeding characteristics by maintaining a straight state without bends when the optical fiber unit is supplied from a bobbin, and to provide its force-feeding method. SOLUTION: In the optical fiber unit and pressure transport method therefor, an optical fiber unit 11 in which a plurality of coated optical fiber tapes 12 are stacked is inserted by the pressurized air flow into a pipe laid in advance. The outermost jacket 14 of the optical fiber unit 11 is formed of a rectangular circumferential surface matching the rectangular outer shape formed by the stack of the coated optical fiber tapes 12. The coated optical fiber tapes 12 are wound so that the stack direction C of the coated optical fiber tapes 12 and the body surface of the bobbin are in parallel and run out of the bobbin into the pipe.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber unit which is laid by being inserted into a pipe by a pressurized air flow, and more particularly to an optical fiber unit for pressure feeding using a plurality of tape cores and a method of feeding the same.

[0002]

2. Description of the Related Art In order to lay an optical fiber indoors or the like, there is known a pressure feeding method in which an optical fiber unit is inserted into a previously laid pipe by a pressure air flow. As the optical fiber unit used for this, a plurality of optical fiber cores are twisted or a plurality of optical fiber tape cores are laminated, and a coating (outer sheath) having a circular cross section with a resin material such as foamed polyethylene. Is known. Recently, an optical fiber unit in which optical fiber tape cores are laminated has been frequently used, but a problem in use has arisen because the outer shape of the jacket is circular.

FIG. 5 is a diagram showing an example of an optical fiber unit in which conventionally used optical fiber ribbons are laminated. In the figure, 1 is an optical fiber unit, 2 is an optical fiber tape core, 3 is a primary coating, 4 is a secondary coating (jacket), and 5 is a drawstring. As the optical fiber ribbon 2 (hereinafter, referred to as a tape ribbon), one obtained by arranging a plurality of optical fibers in a line in parallel and integrating them with a common coating is used. As the optical fiber unit 1, a plurality of four-core tapes 2 are laminated, a primary coating (skin layer) 3 is formed with a coating material such as nylon having a relatively large Young's modulus, and a secondary coating 4 is formed. It prevents the contraction stress from affecting the optical fiber. The outer periphery of the primary coating 3 is formed by forming a secondary coating 4 having a circular outer surface with a resin material such as foamed polyethylene.

The optical fiber unit 1 configured as shown in FIG. 5 is wound around a bobbin 6 and stored until laying.
When the optical fiber unit 1 on which the tape cores 2 are laminated is wound around a bobbin, the optical fiber on the outer side is subjected to elongation strain. However, as shown in FIG. 6, if the lamination direction C of the tape core wire 2 is wound parallel to the body surface 6 a of the bobbin 6 in the winding around the bobbin 6, the length of the optical fiber on the outside and the inside is reduced. Although a difference occurs, each tape core is subjected to the same elongation distortion, so that there is no difference in tape core length between the tape cores 2.
Further, at the time of pressure feeding into the pipe, since the elongation strain of the optical fiber is released and the optical fiber is straightened, there is no particular problem.

However, although the laminated state of the tape cores 2 of the optical fiber unit 1 has directionality, the outer shape of the secondary coating 4 of the optical fiber unit 1 is a circular shape having no directionality. For this reason, it is usually difficult to make the lamination direction C of the tape core wire 2 and the direction of the body surface 6a of the bobbin 6 uniform. FIG.
Indicates a normal winding state, in which the winding direction C of the tape core wire 2 is wound in parallel with the body surface 6a of the bobbin 6 in the entire winding on the bobbin 6, and the stacking direction C is the bobbin. 6, a portion (E) wound at a right angle to the body surface 6a of the bobbin 6, and a portion (G) wound at an angle with the body surface 6a of the bobbin 6 exist. Therefore, the tape core 2
In the portion (F) where the laminating direction C is wound at right angles to the body surface 6a of the bobbin 6, there is a difference in elongation between the outer tape core 2a and the inner tape core 2b.

As a result, as shown in FIG. 8, if there is a winding portion (F) in which the tape core 2 has a difference in elongation, when it is extended linearly, it is located outside at this portion. The tape core length difference between the tape core 2a and the tape core 2b located inside appears. Therefore, when the optical fiber unit 1 is pulled out from the bobbin to be inserted into the pipe, the optical fiber unit 1 itself bends in a meandering manner. If meandering exists in the optical fiber unit itself, meandering in the pipe is further increased, frictional force with the inner wall of the pipe is increased, and it may be difficult to feed and insert the pipe into a long-distance pipe.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and facilitates the insertion of a pressurized airflow into a pipe in a straight state without bending when unreeled from a bobbin. It is an object to provide an optical fiber unit having excellent pumping characteristics and a pumping method thereof.

[0008]

An optical fiber unit according to the present invention is an optical fiber unit in which a plurality of optical fiber tape cores inserted through a pipe laid in advance by a pressurized airflow are laminated, and the outermost layer is provided outside the outermost layer. The cover is formed with a rectangular outer peripheral surface conforming to a rectangular outer shape formed by laminating the optical fiber ribbons.

Further, the method of pumping an optical fiber unit according to the present invention is a method of pumping an optical fiber unit in which an optical fiber unit having a plurality of optical fiber tapes laminated therein is inserted into a pipe laid in advance by a pumping airflow. The outermost layer of the optical fiber unit is formed with a rectangular outer peripheral surface conforming to a rectangular outer shape formed by laminating optical fiber ribbons, and the laminating direction of the optical fiber ribbon and the bobbin body surface are parallel. It is characterized by being wound into a pipe and fed out into a pipe.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a cross section of the optical fiber unit.
Reference numeral 11 denotes an optical fiber unit, 12 denotes an optical fiber tape core, 13 denotes a primary coating, 14 denotes a secondary coating (sheath), 15 denotes a drawstring, and 16 denotes a bobbin. Optical fiber tape 1
2 (hereinafter referred to as a tape core wire) is one in which a plurality of optical fiber wires are arranged in parallel in a row and integrated with a common coating.

The optical fiber unit 11 is formed by laminating a plurality of four core fibers 12 and forming a primary coating (skin layer) 13 with a resin such as nylon having a relatively high Young's modulus. The shrinkage stress of the coating 14 is prevented from affecting the optical fiber. Also, a drawstring 15 is inserted inside the primary coating 13 so that the coating can be easily removed at the time of terminal processing such as branching and connection of an optical fiber. A secondary coating 14 is formed on the outer periphery of the primary coating 13 with a lightweight and foamed polyethylene having a large surface area. The secondary coating 14 is formed so as to conform to the rectangular outer shape obtained by laminating the tape core wires 12, and is formed by coating so that the outer peripheral surface becomes rectangular.

As a sample of a specific example of the present invention, a tape core wire 12 is obtained by coating a glass optical fiber having an outer diameter of 0.125 mm with an ultraviolet curable resin having an outer diameter of 0.25 mm.
The optical fiber strands were arranged in a line in parallel, integrated with a common coating of an ultraviolet curing resin, and taped to a thickness of 0.31 mm and a width of 1.1 mm. Further, for the drawstring 15, stretched polyethylene terephthalate (PET) having an outer diameter of 0.25 mm was used. Six tape cores 12 were laminated without twisting, and covered with a primary coating 13 having a thickness of 0.1 mm with a nylon resin together with the drawstring 15 to form an integral structure.

1. The outer periphery of the primary coating 13 is made of foamed polyethylene (PEF) so as to conform to the rectangular outer shape of the tape core wire 12 laminated in a rectangular shape (same in the width direction of the tape core wire). 2. 7 mm, height (the direction of lamination of the tape core wire)
A secondary coating 14 having a rectangular outer shape of 1 mm was molded as a jacket. The mass of the optical fiber unit 11 after molding is
It was 4.6 g / m.

FIG. 2 shows a view in which the optical fiber unit 11 according to the present invention is wound on a bobbin 16. The optical fiber unit 11 is densely wound on the bobbin 16 so that the laminating direction C of the tape cores 12 is parallel to the body surface 16 a of the bobbin 16. Since the outer shape of the secondary coating 14 is rectangular and has directionality, it can be wound on the bobbin 16 in an aligned winding in which predetermined surfaces of the optical fiber unit 11 are aligned. Note that the laminating direction C of the tape core wire 12 is the body surface 1 of the bobbin 16.
6a to be wound in parallel with the optical fiber unit 11
Any one of the rectangular surfaces may be provided with a color or a streak for identifying the winding surface.

As described above, by winding the optical fiber unit 11 so that the lamination direction C of the tape cores 12 and the body surface 16a of the bobbin 16 are parallel, the winding state of each tape core 12 is changed. Since it is uniform, no irregular twisting occurs. Therefore, the optical fiber unit 11 is connected to the bobbin 1
When it is fed out from 6, it returns to a straight straight line with little meandering bend, and it is possible to perform good insertion without deteriorating the pumping characteristics into the pipe.

FIG. 3 is a diagram showing a comparison between the conventional optical fiber unit 1 and the optical fiber unit 11 according to the present invention in a meandering state when the optical fiber unit is extended from a bobbin.
Shows a comparison diagram, and FIG. 3B shows a definition diagram of the meandering amount measurement.
The meandering amount (width of meandering peaks and valleys) when the optical fiber unit is extended straight from the bobbin is shown in FIG.
As shown in (B), the measured length of the optical fiber unit is 3
m, one end was fixed to a horizontal measuring table, and a 10 g weight was attached to the other end and hung, and the amount of meandering swinging left and right was measured and compared.

As in the case of the embodiment of the present invention, in the sample of the conventional product, the tape core wire 2 was formed by coating a glass optical fiber having an outer diameter of 0.125 mm with an ultraviolet curing resin having an outer diameter of 0.25 mm. Four optical fiber strands are arranged in a line in parallel, integrated with a common coating of ultraviolet curing resin, and have a thickness of 0.3.
1 mm and a 1.1 mm width tape were used.
Further, as the drawstring 5, stretched polyethylene terephthalate having an outer diameter of 0.25 mm was used. And tape core 2
Is laminated without twisting, covered with a primary coating 3 having a thickness of 0.1 mm with nylon resin together with the drawstring 5 to form an integral structure, and the outer periphery is covered with a foamed polyethylene as shown in FIG. A secondary coating 4 having a circular outer shape with a diameter of 2.9 mm was formed as a jacket. The mass of the optical fiber unit 1 after molding was 4.6 g / m, which was the same as the specific example of the product of the present invention.

As a result of measuring a conventional product having the above-mentioned optical fiber unit having a circular jacket by the method shown in FIG. 3B, the meandering amount was 62 mm to 78 mm. On the other hand, the meandering amount of the product of the present invention in which the outer sheath of the optical fiber unit was rectangular was improved significantly from 11 mm to 18 mm, which is 1/4 of the conventional product.

FIG. 4 is a diagram comparing pumping characteristics using the sample product of FIG. Outer diameter 8m for pressure feed pipe
m and an inner diameter of 6 mm were placed in a horizontal state, and the distance that could be inserted by the compressed air flow was measured. As a result,
In the case of the conventional optical fiber unit 1 for pressure feeding, 200 m
I could only pump it for a distance of 300m,
In the pressure feeding of the optical fiber unit 11 of the present invention, the distance of 1500 m could be pumped, and the distance of the pressure feeding could be greatly extended.

[0020]

As is apparent from the above description, according to the present invention, since the covering outer shape of the optical fiber unit is a rectangular shape along with the lamination of the tape core wire, the winding direction on the bobbin is directional. Can be held. This makes it possible to wind the optical fiber unit in parallel with the laminating direction of the tape core wire and the body surface of the bobbin over the entire length, thereby minimizing meandering of the optical fiber unit during pressure feeding into the pipe. Can be suppressed, and the pumping distance can be greatly increased.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an optical fiber unit showing an embodiment of the present invention.

FIG. 2 is a diagram showing a wound state of the optical fiber unit of the present invention.

FIG. 3 is a diagram comparing the meandering amounts of a product of the present invention and a conventional product.

FIG. 4 is a diagram comparing the pumping distance of a product of the present invention and a conventional product.

FIG. 5 is a sectional view of a conventional optical fiber unit.

FIG. 6 is a diagram showing an ideal winding state of a conventional optical fiber unit.

FIG. 7 is a diagram showing a normal winding state of a conventional optical fiber unit.

FIG. 8 is a diagram showing a state where a conventional optical fiber unit is extended from a bobbin.

[Explanation of symbols]

11: Optical fiber unit, 12: Optical fiber ribbon, 13: Primary coating, 14: Secondary coating (jacket), 15:
Drawstring, 16 ... bobbin.

Claims (3)

[Claims] An optical fiber unit in which a plurality of optical fiber ribbons are inserted into a pipe laid in advance by a pressurized air flow, and an outermost layer is formed of a rectangular shape formed by laminating the optical fiber ribbons. An optical fiber unit characterized by being formed with a rectangular outer peripheral surface conforming to the outer shape. 2. The optical fiber unit according to claim 1, wherein the optical fiber unit is wound so that the laminating direction of the optical fiber ribbon and the bobbin surface are parallel to each other. 3. A method of pumping an optical fiber unit in which an optical fiber unit in which a plurality of optical fiber tape cores are stacked is inserted into a pipe laid in advance by a pressurized air flow, wherein the outermost layer of the optical fiber unit is The jacket is formed with a rectangular outer peripheral surface conforming to a rectangular outer shape formed by laminating the optical fiber ribbons, and wound so that the laminating direction of the optical fiber ribbons and the body surface of the bobbin are parallel. A pressure feeding method for an optical fiber unit, wherein the method is fed into a pipe.