JP2014115312A - Optical cable and single core separation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical cable and a single core separation method for being capable of safe, simple, and easy separation of a single core without using special tools on a work site while reducing manufacturing costs.SOLUTION: An optical cable 11' is configured such that a plurality of coated optical fiber ribbons 20 integrally composed of a plurality of coated optical fibers 21 to 24 with a batch covering 25 are aggregated and covered with an upper winding tape 13 to cover an outside thereof with a sheath 14. Notches 27 for exposing the coated optical fibers are formed between the coated optical fibers covered in a batch.

Description

  The present invention relates to an optical cable in which a plurality of optical fiber cores are integrated with a cover and an optical fiber tape core is covered with an overwound tape and the outside is covered with a sheath, and a method of separating the optical cable from a single core. .

  With the recent expansion of broadband services such as video distribution, IP telephony, and data communications, the number of subscribers to home-use data communications services (FTTH: Fiber To The Home) using optical fibers is increasing. In this FTTH, a drop optical cable is used to drop from an aerial or underground trunk optical cable to a subscriber's house. For example, an optical fiber is dropped to a subscriber's home by, for example, a trunk optical cable laid on a utility pole in a city is branched by a connection box usually called a closure, and a drop optical cable is dropped on the branched optical fiber. Are connected using fusion splicing or an optical connector.

  The branching operation for drawing the optical fiber from the middle portion of the trunk optical cable is also called intermediate post-branching. First, the sheath of the branch portion of the trunk optical cable is removed at a constant length of about 500 mm, for example. Next, the exposed upper winding tape is cut using a cutter such as a cutter. Subsequently, when the top wound tape is unwound and peeled off, and the optical fiber ribbon contained in the trunk optical cable is taken out, one to several optical fibers can be branched.

However, when a cutting tool such as a cutter is used to cut the sheath or the upper winding tape, the optical fiber ribbon may be damaged by the cutting tool.
On the other hand, for example, in Patent Document 1, a gutter plate that can hold the optical fiber tape core wire in the thickness direction is provided, and a spring is provided so that the gutter plate abuts on the optical fiber tape cord wire with a constant pressing force. A technique is disclosed in which the cover of the optical fiber ribbon is damaged by the scissors by sliding the tool in this state and sliding the tool in that state.

In Patent Document 2, a pair of tool bases are closed to make a cut at the center of the optical fiber tape core (four cores) supported in the support groove by the separating blade. A technique is disclosed in which a single core is separated by cutting in the center of the split optical fiber ribbon (two cores).
Further, in Patent Document 3, shear stress is generated in the collective coating by squeezing with an ironing member having an elastic modulus larger than the elastic modulus of the collective coating of the optical fiber ribbon and smaller than the elastic modulus of the optical fiber colored layer. A technique is disclosed in which only this collective coating is broken.

Further, Patent Document 4 includes a plurality of flexible members that abut on at least one surface of an optical fiber ribbon, and a single-fiber optical fiber separated from the optical fiber ribbon between the members. Has disclosed a technology that can accommodate one or more.
Further, in Patent Document 5, a protrusion having a Young's modulus larger than the Young's modulus of the batch coating of the optical fiber ribbon is provided on the upper tape, and the batch coating is broken by rubbing the batch coating with the upper tape. The technique made to do is disclosed.

JP-A-10-319251 Japanese Patent Laid-Open No. 2004-70060 JP 2004-317671 A JP 2006-106157 A JP 2011-141385 A

By the way, the branching operation of the optical fiber core wire is often performed in a poor working environment such as on a power pole or a bucket car, and it is desired to be as safe, simple and easy as possible. However, all of the techniques described in Patent Documents 1 to 4 require a dedicated single-core separating tool, and the operator must be familiar with how to use the dedicated tool. Can't meet.
In this case, according to the technique described in Patent Document 5, it is not necessary to use a special tool at the work site, and single-core separation can be performed safely, easily and easily. Since an overwound tape is required, it is difficult to reduce the manufacturing cost of the optical cable.

  The present invention has been made in view of the above circumstances, and can reduce the manufacturing cost and can perform single-core separation safely, simply and easily without using a special tool at the work site. And to provide a single-core separation method.

  An optical cable according to the present invention is an optical cable in which a plurality of optical fiber ribbons integrated with a plurality of optical fiber cores are collectively covered and covered with an upper winding tape, and the outside is covered with a sheath, A notch for exposing the optical fiber core wire is formed between the optical fiber core wires of the collective coating.

  In addition, the optical fiber ribbon may have a recess extending along the longitudinal direction of the optical fiber core between the optical fiber cores that are collectively covered, and the notch may be formed in the recess. Further, the cutouts may not be provided on both sides of the same optical fiber core in the parallel direction of the optical fiber core. Moreover, it is desirable that the side edges in the longitudinal direction of the upper winding tape have intermittent cuts.

  In addition, the optical fiber single-core separation method described above is a method in which a plurality of optical fiber cores are integrated with a batch coating, and a notch that exposes the optical fiber core wire is formed between the batch-coated optical fiber core wires. An optical cable single-fiber separation method in which a fiber tape core is covered with an upper winding tape and the outside is covered with a sheath, the optical fiber tape being an upper winding tape that has been removed from the optical cable by a predetermined length and immersed in alcohol. By squeezing the core wire in the longitudinal direction, the optical fiber core wire can be separated from the optical fiber tape core wire.

  According to the optical cable of the present invention, a notch that exposes the optical fiber core wire inside the batch coating constituting the optical fiber tape core wire is formed, for example, alcohol is collectively covered through the notch. It is possible to penetrate between the optical fiber core wires. As a result, it is possible to perform single-core separation safely, easily and easily without using a special tool at the work site while reducing the manufacturing cost.

It is a figure explaining an example of the optical cable by this invention. It is a figure explaining an example of the optical cable by this invention. It is a figure explaining an example of an optical fiber tape cable core. It is a figure for demonstrating an example of the single core isolation | separation method by the optical cable of this invention.

  An embodiment of the present invention will be described with reference to FIGS. FIG. 1A shows an outline of an optical cable, and FIG. 1B is a diagram for explaining an application example to a slot type optical cable. In the figure, 11 and 11 'are optical cables, 12 is a collective core, 13 is an upper winding tape, 14 is a sheath, 15 is a slot, 15a is a storage groove, 15b is a rib, 16 is a tension member, and 20 is an optical fiber ribbon. Indicates.

  As shown in FIG. 1, the optical cable of the present invention is intended for optical cables 11 and 11 ′ having a structure in which the outer periphery of the collective core 12 in a state where a plurality of optical fibers are accommodated and bundled is covered with a sheath 14. The collective core 12 is a multi-core optical fiber ribbon that is assembled in a slotless manner, and the outside thereof is bundled with an upper winding tape (also referred to as a press-wound tape) 13 or the like, The optical fiber ribbon is stored in the slot 15 shown in FIG. 1B and is held by the upper winding tape 13 or the like.

A slot-type optical cable 11 ′ shown in FIG. 1B is a trunk optical cable that is widely used as a trunk optical cable laid in an underground conduit or the like. This optical cable 11 'is constituted by a resin slot (also referred to as a spacer) 15 in which a tension member (also referred to as a tensile body) 16 is embedded and integrated at the center and a plurality of storage grooves 15a are provided.
The storage grooves 15a have a bottom surface on the tension member 16 side, are arranged at substantially equal intervals along the circumferential direction of the slot 15, and adjacent storage grooves 15a are separated by ribs 15b.

As shown in FIG. 2, the storage groove 15a is formed in a spiral shape or SZ shape along the longitudinal direction of the optical cable 11 ′, and a plurality of optical fiber ribbons 20 are stored in the storage groove 15a. .
The upper winding tape 13 is applied to the outer periphery of the slot 15 in a state where the optical fiber ribbon 20 is housed in the housing groove 15a. The upper-winding tape 13 holds the optical fiber ribbon 20 stored in the storage groove 15a so that it does not jump out. Therefore, a water absorbing agent can be added to function as a water absorbing layer.

The upper winding tape 13 is a non-woven fabric or a laminate including fibers of a low melting point thermoplastic resin (for example, polyester), and the tape width can be, for example, about 10 mm to 30 mm.
The upper winding tape 13 can be in a form of either a horizontal winding wound in a spiral shape or a vertical winding in the longitudinal direction of the optical cable 11 ′, and is assembled in a state where the upper winding tape 13 is applied. The core 12 is used.

The upper winding tape 13 is configured so that an operator can cut it by hand. For example, the upper winding tape 13 has a cut 13a. The cut line 13a shown in FIG. 2 is intermittently provided on the side edge in the longitudinal direction of the upper winding tape 13, so that the breaking tension in the longitudinal direction of the upper winding tape 13 is 100 N / 25 mm width or less, for example, Are set at intervals of about 150 mm for a tape width of 25 mm.
A rough winding 17 such as a nylon thread or a plastic tape may be applied outside the slot 15 and inside the upper winding tape 13.

  The collective core 12 is covered with an extruding sheath 14. The sheath 14 is formed by extruding, for example, a polyethylene resin or a flame-retardant polyethylene resin on the outside of the collective core 12. The sheath 14 is wound around the upper winding tape 13 by temporarily winding the assembly core 12 around a drum or the like, and is then formed around the upper winding tape 13 without being wound around the drum. In some cases, it is formed following the winding of 13.

The present invention is characterized in that the above-described optical fiber tape core wire 20 is provided with a notch that exposes the inside of the batch coating.
3A is an external perspective view of the optical fiber ribbon 20 and FIG. 3B is a cross-sectional view. The optical fiber ribbon 20 includes, for example, four optical fiber cores 21 to 24 arranged in parallel on a plane, and these four optical fiber cores 21 to 24 are covered with a common collective covering 25 and tape. It is formed in a shape. Note that the optical fiber ribbon can also be composed of 6 or 8 optical fibers.

  The optical fiber core in the present invention, the glass portion consisting of the core and the clad, what is referred to as an optical fiber strand simply provided with an optical fiber UV resin layer covering the glass portion, and As shown in the optical fiber core wire 21 shown in FIG. 3, the optical fiber UV resin layer 21b covering the glass portion 21a is coated with a colored layer 21c on the outer surface. The colored layer 21c of the optical fiber core 21 is colored blue, for example.

Similarly to the optical fiber core wire 21, the optical fiber core wires 22 to 24 have a glass portion and an optical fiber UV resin layer, and, for example, a white colored layer 22 c is formed on the outer surface of each optical fiber UV resin layer. , Brown colored layer 23c and gray colored layer 24c.
These four optical fiber core wires 21 to 24 are integrated with a collective coating 25 made of, for example, an ultraviolet curable resin. In FIG. 3B, T represents the tape thickness of the optical fiber ribbon 20 and D represents the outer diameter of the optical fibers 21 to 24. For example, the tape thickness T is about 0.28 mm, The outer diameter D is about 0.25 mm. For this reason, the coating thickness by the collective coating 25 is configured to be 0.02 mm or less, for example.

  Here, the collective coating 25 preferably has a recess 26 between the optical fiber core wires. Specifically, as shown in FIG. 3, the recess 26 is formed between the optical fiber core wire 21 and the optical fiber core wire 22, between the optical fiber core wire 22 and the optical fiber core wire 23, and the optical fiber core wire 23. They are respectively formed between the optical fiber core wires 24 and extend along the longitudinal direction of the optical fiber core wires 21 to 24.

  The collective covering 25 is provided with a notch 27. The notch 27 shown in FIG. 3 is formed only on one surface side of the optical fiber ribbon 20 and is provided in the recess 26 of the collective coating 25, but the optical fibers 21 to 24 are arranged in parallel. It is arranged not to be provided on both sides of the same optical fiber core wire in the direction. Specifically, the notch 27 is formed only between the optical fiber core wire 21 and the optical fiber core wire 22, and between the optical fiber core wire 23 and the optical fiber core wire 24. It is not formed between the optical fiber core wire 23.

  The cutout 27 is formed so that the colored layer is exposed. From the cutout 27 provided between the optical fiber core wire 21 and the optical fiber core wire 22, for example, a blue colored layer 21 c and a white color layer are formed. The colored layer 22 c can be seen from the outside of the collective coating 25 through the notch 27. Further, from the notch 27 provided between the optical fiber core wire 23 and the optical fiber core wire 24, a brown colored layer 23 c and a gray colored layer 24 c are connected to the collective coating 25 via the notch 27. It can be seen from the outside.

The portions where the cutouts 27 are formed are intensively crushed as will be described later, and pulled in a direction in which they are separated from each other (a direction perpendicular to the longitudinal direction of the optical fiber core wire), thereby making it easier to tear the collective coating 25 be able to.
The notches 27 are intermittently formed along the longitudinal direction of the optical fiber core, and the cut portions and the non-cut portions having a predetermined length are alternately provided. The cut portion can be formed in various patterns. In FIG. 3, the positions of the adjacent notches 27 in the parallel direction of the optical fiber core wires 21 to 24 are formed to coincide with each other. However, the positions of the adjacent notches may be different.

  In addition, the length of the cut portion and the length of the non-cut portion can be arbitrarily set.For example, when importance is attached to the single fiber separation of the optical fiber core wire, the length of the cut portion is set to be longer than that of the non-cut portion. Lengthen. On the other hand, when importance is attached to the integrity of the optical fiber ribbon, the length of the non-cut portion is made longer than the cut portion. Alternatively, when balancing single-core separation and unity, the lengths of the cut portion and the non-cut portion may be equal.

  The notch 27 is cut with a cutter blade after the optical fiber core wires 21 to 24 are integrated with the batch coating 25. Alternatively, the batch coating may be extruded so that a cut portion can be formed. Moreover, although the notch demonstrated in FIG. 3 was intermittently formed along the longitudinal direction of an optical fiber core wire, it can also be continuously formed along the longitudinal direction of an optical fiber core wire. .

FIG. 4 is a diagram for explaining an example of the single-core separation method using the optical cable of the present invention.
In branching the optical cable, first, the operator removes a portion of the sheath 14 of the optical cable 11 ′ that is desired to be branched at an intermediate length. In the portion where the sheath 14 is removed, the upper winding tape 13 is exposed.
Since the upper tape 13 has a cut line 13a, the operator can easily stand the cut line 13a by scratching with a nail or the like.

And as shown to FIG. 4 (A), if the part of the standing cut 13a is picked with a finger and it pulls in the formation direction of the cut 13a, the continuously wound upper tape 13 can be cut. . By unwinding the upper winding tape 13 cut at the cut line 13a, the upper winding tape 13 can be peeled off for a predetermined length.
Next, the upper winding tape 13 of a predetermined length is immersed in, for example, ethanol, while the optical fiber ribbon 20 is taken out from the optical cable 11 ′.

  Thereafter, the upper winding tape 13 having a predetermined length shown in FIG. 4B is folded in two to sandwich the optical fiber ribbon 20, and the upper winding 13 is laid in the longitudinal direction of the optical fiber ribbon 20. As a result, ethanol enters the optical fiber tape core wire 20 from the notch 27 between the optical fiber core wires 21 and 22, and between the cover 25 and the colored layer 21c shown in FIG. And soaks between the collective coating 25 and the colored layer 22c. Further, when ethanol enters the optical fiber ribbon 20 from the notch 27 between the optical fibers 23 and 24, the ethanol is between the collective coating 25 and the colored layer 23c, and between the collective coating 25 and the colored layer 24c. Immerse in.

Subsequently, the operator peels the collective coating 25 from the colored layers 21c to 24c and takes out the optical fiber core wires 21 to 24 therein. As a result, it is safe, simple and easy to connect the optical fiber cores 21 to 24 from the optical fiber tape core 20 without using a special tool at the work site while reducing the manufacturing cost by using the general-purpose upper winding tape 13. Single core separation can be performed.
If it demonstrates based on a specific example, as mentioned above, optical cable 11 'will be produced using the tape width 25mm and the upper winding tape 13 (nonwoven fabric) of 150 mm of gap | intervals of a break | interval.

When the single core is separated, the sheath 14 is removed from the optical cable 11 ′ by about 500 mm, and a piece having a length of 150 mm is taken out from the upper winding tape 13 along the exposed cut 13 a of the upper winding tape 13.
When this piece of the upper wound tape 13 is immersed in ethanol and applied to the optical fiber ribbon 20 taken out of the storage groove 10 times with a stroke of about 50 mm in the longitudinal direction, the optical fiber is damaged. Without being separated. Moreover, if the upper winding tape 13 immersed in ethanol is used, the collective coating 25 partially remaining around the optical fiber core wire can be wiped off and easily removed.

The optical fiber ribbon 20 is of the type having the recess 26 and the notch 27 described in FIG. 3, and the optical fiber ribbon 20 has a tape thickness T of about 0.28 mm and optical fibers 21 to 24. Has an outer diameter D of about 0.25 mm.
On the other hand, for reference, an optical fiber ribbon having no notch was rubbed with a similar nonwoven fabric soaked in ethanol, but it could not be separated into a single core even after squeezing 30 times or more.

  In FIG. 4, the example in which the upper winding tape is immersed in ethanol is described. However, ethanol may be applied to the batch coating of the optical fiber ribbon taken out from the optical cable without immersing the upper winding tape in ethanol. Also in this case, ethanol enters the optical fiber ribbon from the notch, and the batch coating can be easily peeled off from the optical fiber.

DESCRIPTION OF SYMBOLS 11, 11 '... Optical cable, 12 ... Collective core, 13 ... Top wound tape, 13a ... Cut, 14 ... Sheath, 15 ... Slot, 15a ... Storage groove, 15b ... Rib, 16 ... Tension member, 17 ... Coarse winding, 20 ... optical fiber ribbon, 21-24 ... optical fiber, 21a ... glass part, 21b ... UV resin layer for optical fiber, 21c-24c ... colored layer, 25 ... collective coating, 26 ... depression, 27 ... notch .

Claims (5)

An optical cable in which a plurality of optical fiber ribbons, in which a plurality of optical fiber cores are integrated with a single coating, are gathered and covered with an upper winding tape, and the outside is covered with a sheath,
An optical cable characterized in that a notch for exposing the optical fiber core wire is formed between the optical fiber core wires covered in batch.   The optical fiber ribbon has a recess extending along the longitudinal direction of the optical fiber between the batch-coated optical fibers, and the notch is formed in the recess. The optical cable according to claim 1.   3. The optical cable according to claim 1, wherein the notch is not provided on both sides of the same optical fiber in the parallel direction of the optical fiber. 4.   4. The optical cable according to claim 1, wherein a side edge in a longitudinal direction of the upper winding tape is intermittently cut. 5. A plurality of optical fiber cores are integrated with a single coating, and a notch that exposes the optical fiber core covers the optical fiber tape core formed between the optical fiber cores of the batch coating with an overwrapping tape. , A method of separating a single core of an optical cable having an outer sheath coated with a sheath,
Separating the optical fiber core from the optical fiber ribbon in a single direction by squeezing the optical fiber ribbon in the longitudinal direction with an upper winding tape that has been removed from the optical cable by a predetermined length and immersed in alcohol. A single-core separation method characterized by the above.

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