JP2012083475A - Optical cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a slotless type optical cable allowing a coated optical fiber to be easily ejected and preventing an exterior covering and a tension member, such as a steel wire, from displacing during laying operation.SOLUTION: A slotless type optical cable 1 comprises a plurality of coated optical fibers, a protective layer 3 provided around the plurality of coated optical fibers, an exterior covering 4 for covering periphery of the protective layer 3, and a tension member 5. The tension member 5 is integrated with the inner surface of the exterior covering 4 in tape shape.

Description

  The present invention relates to an optical fiber cable that accommodates a plurality of optical fiber cores.

Conventional typical multi-core optical cables include a slot-type optical cable and a slotless-type optical cable.
For example, as shown in FIG. 5, the slot-type optical cable stores a plurality of optical fiber ribbons 101 in a plurality of slot grooves 102 a formed on the outer periphery of a slot rod (also referred to as a spacer) 102. The pressing tape 103 is wound around the outer periphery of the outer periphery, and the outer cover 104 is further covered. At the center of the slot rod 102, a steel wire 102b is provided as a strength member.

On the other hand, in the slotless type optical cable, as shown in FIG. 6, a plurality of optical fiber ribbons 201 are surrounded by a protective layer 202 such as a polypropylene yarn that protects against an external force and the outside is covered with a jacket 203. It is a thing. Further, unlike the slot-type optical cable, the slotless optical cable has a steel wire 203a embedded in the outer sheath 203.
Such a slotless optical cable can be manufactured at a low cost because it has fewer components than a slot-type optical cable.

JP 2001-66481 A

  The above-described multi-fiber optical cable has to be removed because it is necessary to take out the optical fiber ribbon from the jacket at the end of the cable or at the middle of the cable when connecting the cores. . In the case where the outer sheath does not have a steel wire as in the case of the slot type optical fiber cable of FIG. 5, this removal is performed after making an annular cut in the outer sheath using a tool such as an outer cutter (outer sheath). This is done after making a circle.

  FIG. 7 is a diagram for explaining an example of a procedure for cutting the outer cover of the optical cable. In the figure, reference numeral 300 indicates the cover cutter. The outer cutter 300 includes a tool main body 301 and a blade insertion screw 302. First, the operator sets the tool main body 301 at a position where the optical cable is to be cut (S101), and in this state, the blade insertion screw 302 is rotated in the direction shown in the figure to insert the blade 303 into the outer cover of the optical cable 1 (S102). ). Then, when the operator rotates the tool main body 301 in the illustrated direction (clockwise) in this state, the blade 303 is also rotated accordingly, and the outer cover is cut in a circle (S103).

  However, in the case of a structure in which two steel wires 203a are embedded in the jacket 203 as in the slotless optical cable 200 of FIG. 6, in the jacket cutter 300 of FIG. 7, the rotated blade 303 hits the steel wire 203a. Therefore, the outer cover 203 cannot be cut in a state where the blade 303 is inserted deeply. That is, the jacket cutter 300 cannot be used. For this reason, the removal of the jacket is performed using a cutter knife or the like, which is a problem in terms of safety and work efficiency.

  In addition, in the slotless type optical cable, a structure in which the steel wire is provided at the center of the cable instead of the jacket is also conceivable. However, with this structure, when laying, the steel wire is not integrated with the jacket when the central steel wire is gripped with a terminal tool such as a pooling eye, so there is an obstacle in the laying route. The outer sheath may be separated from the steel wire due to friction of an object or the like, and may be displaced in a direction opposite to the pulling direction of the optical cable.

  The present invention has been made in view of the above circumstances, and is a slotless optical cable in which an optical fiber core wire can be easily taken out and a sheath and a tension member such as a steel wire do not shift during laying work. The purpose is to provide.

  An optical cable of the present invention includes a plurality of optical fiber core wires, a protective layer provided around the plurality of optical fiber core wires, a jacket covering the periphery of the protective layer, and a tension member. The tension member is integrated with the inner surface of the outer cover in a tape shape.

  It is preferable that the inner surface of the jacket is formed in an oval shape in a sectional view, and a tension member is disposed on the short diameter side, and the jacket and the tension member are intermittent in the longitudinal direction of the optical cable. It is also preferable to be adhesively fixed to. It is preferable that a notch be provided along the longitudinal direction of the optical cable on the outer side or the inner side of the jacket of the portion where the tension member does not exist.

  According to the optical cable of the present invention, since the tension member is bonded or welded to the inner surface of the jacket, the jacket can be easily cut using a tool such as a jacket cutter, and during installation work. In addition, the outer cover and the tension member are not displaced.

It is sectional drawing explaining an example of the optical cable of this invention. It is sectional drawing explaining the other example of the optical cable of this invention. It is a side view which shows another example of the optical cable of this invention. It is sectional drawing explaining another example of the optical cable of this invention. It is a figure explaining an example of a general slot type optical cable. It is a figure explaining an example of the conventional slot type optical cable. It is a figure explaining the process performed when making an annular cut | interruption in an optical cable.

  Hereinafter, preferred embodiments of the optical cable of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing an example of an optical cable according to the present invention, in which 1 denotes the optical cable. The optical cable 1 includes an optical fiber core assembly, that is, an optical fiber core bundle 2, a protective layer 3, a jacket 4, and a tension member 5.

  The optical fiber core bundle 2 is formed, for example, by stacking a plurality of optical fiber core wires arranged in parallel in a tape shape by arranging them in an ultraviolet curable resin. The optical fiber core bundle 2 is not limited to a tape core, but may be a plurality of single optical fiber cores arranged side by side. Below, this is demonstrated as the tape core wire bundle 2. FIG. The protective layer 3 is formed of polypropylene yarn or the like, and protects the tape core bundle 2 from an external force or the like. The jacket 4 is made of a thermoplastic resin such as an olefin resin (for example, polyethylene).

  In the present invention, as the tension member (also referred to as a tensile body) 5, a tape-shaped member in which a wire having resistance to tension and compression is covered with a thermoplastic resin such as polyethylene is used. In addition, as said wire, a steel wire, FRP (Fiber Reinforced Plastics), etc. are used, for example. Hereinafter, the tension member 5 is referred to as a tension member tape 5.

  The main feature of the present invention is to facilitate the removal of the outer cover of the slotless optical cable and to prevent the outer cover and the tension member from shifting during the laying operation. As a configuration for that purpose, the slotless optical cable 1 includes a tape core bundle 2, a protective layer 3 provided around the tape core bundle 2, a jacket 4 covering the periphery of the protective layer 3, and a tension member tape 5. The tension member tape 5 is integrated with the inner surface of the outer cover 4 and enters the protective layer 3. In the illustrated example, two tension member tapes 5 are provided so as to oppose each other with the core wire bundle 2 interposed therebetween.

  As described above, since the tension member tape 5 is integrated with the inner surface of the outer cover 4, that is, disposed inside the outer cover 4, a sufficient depth is provided in the outer cover 4 using a tool such as the outer cover cutter. An annular cut can be made. After two such cuts are made, the tension member tape 5 at that location is cut with a nipper or the like, and the outer cover and the tension member tape 5 are removed by making a cut in the cable longitudinal direction in the outer cover 4 to remove the tape core. The line can be taken out. As described above, the slotless optical cable 1 is easy to take out the tape core wire.

In addition, since the tension member tape 5 and the outer cover 4 are integrated, even when the tension member tape 5 is gripped by a terminal tool such as a pooling eye and attached tow, the outer cover 4 and the outer cover 4 are tensioned during the attaching operation. The member tape 5 is not displaced.
In addition, as a method of integrating the tension member tape 5 and the jacket 4, a method of melting polyethylene around the tension member of the tension member tape 5 by heat and welding the jacket 4 to the jacket 4 when the jacket 4 is extruded. There is.

FIG. 2 is a cross-sectional view showing another example of the optical cable according to the present invention, in which 10 denotes an optical cable. In addition, about the part similar to the optical cable 1 of FIG. 1 of this optical cable 10, the same referential mark is attached | subjected and the description is abbreviate | omitted.
In the optical cable 10 of FIG. 2, unlike the optical cable 1 of FIG. 1, the shape of the hollow portion 11a of the jacket 11 is an ellipse having a long diameter in the direction perpendicular to the opposing direction of the tension member tape 5. Since the locus of the tip of the blade of the jacket cutter is close to a perfect circle (refer to the dotted line in the figure), the hollow portion 11a of the jacket 11 of the optical cable 10 has an elliptical shape as described above, so that it is The biting of the blade of the cutter is deepened, and the portion other than the portion where the tension member tape 5 of the jacket 4 is welded can be reliably cut.

FIG. 3 is a side view showing another example of the optical cable according to the present invention, in which 20 denotes an optical cable. Similarly to the optical cable 1 of FIG. 1 and the optical cable 10 of FIG. 2, the optical cable 20 also has a tension member tape integrated with the inner surface of the outer cover 21.
In the example of FIG. 1, as a method of integrating the tension member tape and the outer cover, a method of welding the two is given. However, the present invention is not limited to this method. For example, the material covering the wire of the tension member tape is thermoplastic. It is also possible to use a material other than resin. In this case, an adhesive is applied to at least the surface of the outer cover side of the covering portion, and the tension member tape and the outer cover can be integrated by bonding. .

When the above integration is performed by adhesive fixing as described above, it is preferable that the tension member tape and the protective layer side of the jacket, that is, the inner surface are intermittently bonded and fixed in the longitudinal direction of the optical cable. If an annular cut is made using a jacket cutter at a location where the tension member tape and the outer cover are not bonded, the outer member and the tension member tape are not integrated at that point, so the tension member can be easily The tape can be cut.
As a method of intermittently bonding and fixing as described above, a method of intermittently applying an adhesive to a tension member tape supplied at the time of manufacturing an optical cable can be considered.

  In the case of this configuration, for example, as shown in FIG. 3, the shape of the outer cover 21 of the portion 21 a that is not bonded and fixed may be convex in a side view so that a portion that is not bonded and fixed can be distinguished from the outside. Further, it may be possible to make a distinction by coloring a portion that is not bonded and fixed.

In order to facilitate tearing of the optical cable of the above example in the longitudinal direction, a tearing string may be provided although illustration is omitted. Moreover, it is good also as a structure as shown in FIG. 4 instead of providing a tear string.
FIG. 4 is a cross-sectional view showing another example of the optical cable according to the present invention, in which 30 and 40 indicate optical cables. In addition, about the part similar to the optical cable 1 of FIG. 1 of these optical cables 30 and 40, the description is abbreviate | omitted by attaching | subjecting the same referential mark.

The optical cable 30 in FIG. 4A has a notch extending in the longitudinal direction at a position displaced from the tension member tape 5 outside the outer cover 31. 4B has a notch extending in the longitudinal direction at a position displaced from the tension member tape 5 inside the jacket 41.
As described above, the notch 31a is provided on the outer side of the outer cover 31 or the notch 41a is provided on the inner side of the outer cover 41. , 41 can be torn.

DESCRIPTION OF SYMBOLS 1,10,20,30,40 ... Optical cable, 2 ... Tape core bundle, 3 ... Protective layer, 4, 11, 21, 31, 41 ... Outer sheath, 5 ... Tension member tape.

Claims (4)

An optical cable comprising a plurality of optical fiber cores, a protective layer provided around the plurality of optical fiber cores, a jacket covering the periphery of the protective layer, and a tension member,
The optical cable, wherein the tension member is tape-shaped and integrated with an inner surface of the jacket.   2. The optical cable according to claim 1, wherein an inner surface shape of the jacket is formed in an oval shape in a cross-sectional view, and the tension member is disposed on a short diameter side thereof.   The optical cable according to claim 1, wherein the jacket and the tension member are intermittently bonded and fixed in the longitudinal direction of the optical cable.   The optical cable according to any one of claims 1 to 3, wherein a notch is provided along a longitudinal direction of the optical cable on an outer side or an inner side of the jacket of a portion where the tension member does not exist.

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