JP2012098583A - Optical cable - Google Patents

Abstract

An optical cable capable of safely tearing a sheath without damaging an optical fiber and without requiring operator skill or a tear string.
An optical cable in which a sheath is coated on the outer periphery of an aggregate core that accommodates a plurality of optical fibers, and tearing members that reach the outer surface of the sheath from the inner surface of the sheath along the longitudinal direction of the sheath are provided. It is provided. It is preferable that the tear members 18a to 18d protrude outward from the outer surface of the sheath. Further, the tearing member is preferably formed of a resin different from the sheath, and can be provided with a previously formed member attached vertically. The collective core 12 preferably has a slot rod 15 that accommodates a plurality of optical fibers and a press-winding tape 13 that covers the outer periphery thereof, and the tearing members 18a to 18d are in contact with the press-winding tape.
[Selection] Figure 1

Description

  The present invention relates to an optical cable that is used for indoor and outdoor optical wiring and in which a sheath is coated on the outer periphery of a collective core that accommodates a plurality of optical fibers.

An optical cable containing a plurality of optical fibers is laid as an optical cable for a trunk line, but the optical fiber is branched (also referred to as an intermediate branch) in order to be pulled down to a user at an arbitrary point. In this case, the optical cable sheath is cut and peeled off within the length range necessary for branching (for example, about 50 cm), and some of the stored optical fibers are taken out and branched using a closure or drop cable. ing.
For example, as shown in Patent Document 1, a tear string is arranged on the inner surface side of a sheath in an optical cable so that the sheath can be torn and peeled off easily.

  FIG. 3 is a diagram illustrating an example of a conventional sheath tearing method disclosed in Patent Document 1 described above. When the optical fiber is taken out from the intermediate portion of the optical cable 1, first, as shown in FIG. 3A, the cutter 4 is used in the intermediate portion, and two cuts 3 a are cut into the cable sheath 2 in a ring shape. Next, as shown in FIG. 3B, a cut 3b connecting the two cuts 3a is inserted in the cable axial direction, and the loop-shaped sheath portion 2a generated by the cut is removed. When the loop-shaped sheath portion 2a is removed, as shown in FIG. 3C, the collective core 5 composed of a bundle or slot of optical fibers is exposed. At this time, the tear string 6 arranged in the cable is exposed and can be pulled out. As a result, as shown in FIG. 3 (D), the tear 3c is inserted into the sheath 2 by the tear string 6, and the sheath in a predetermined range is removed.

  FIG. 4 is a diagram showing an example of another method for tearing the sheath. First, as shown in FIG. 4 (A), one notch 3a is cut into the cable sheath 2 in a ring shape by using a cutter 4 at an intermediate portion thereof. Next, as shown in FIG. 4 (B), two cuts 3b (for example, a distance of 6 to 8 mm and a length of about 100 mm) are made in the cable axial direction with the cut 3a as the starting end, and the strip 2b formed by this cut. Tear off. When the strip 2b is peeled off, as shown in FIG. 4 (C), the aggregate core 5 composed of a bundle or slot of optical fibers is exposed, and the tear string 6 disposed in the cable is exposed and pulled out. be able to. Next, as shown in FIG. 4D, the tear string 6 is cut to form a tear end, and the sheath 2 is torn like the example of FIG.

JP 2008-158368 A

  As shown in FIGS. 3 and 4, when the sheath 2 of the optical cable is removed using the cutter 4, it is necessary not to damage the optical fiber with the blade of the cutter 4, particularly when the axial cut 3 b is made. There is also a method of gradually scraping the cable sheath from the outside so as not to damage the internal optical fiber, but this is not reliable and requires time. Normally, the surface of the collective core 5 is wound with presser foot tape, so it is necessary to stop the cutting depth of the cutter 4 just before it reaches the presser foot tape. There was a problem that was not good.

  The present invention has been made in view of the above-described situation, and an object of the present invention is to provide an optical cable that can safely tear the sheath without damaging the optical fiber and without requiring the operator's skill or tear string. And

An optical cable according to the present invention is an optical cable in which a sheath is coated on the outer periphery of a collective core in which a plurality of optical fibers are accommodated, and a tearing member that extends from the inner surface of the sheath to the outer surface of the sheath is provided along the longitudinal direction of the sheath. It is characterized by that. It is preferable that the tearing member protrudes outward from the outer surface of the sheath. Further, the tearing member is preferably formed of a resin different from that of the sheath, and can be provided with a previously formed member attached vertically.
Further, the aggregate core preferably has a slot rod that accommodates a plurality of optical fibers and a press-winding tape that covers the outer periphery thereof, and the tearing member is in contact with the press-winding tape.

  According to the above optical cable according to the present invention, since no tear string is required, the process of taking out the tear string can be eliminated, the workability can be improved, and the cutting with the cutter in the cable axial direction can be eliminated. The sheath can be safely cut.

It is a figure explaining embodiment of the optical cable by this invention. It is a figure explaining an example of the sheath tearing of the optical cable by this invention. It is a figure explaining a prior art. It is a figure explaining other prior art.

  An embodiment of the present invention will be described with reference to FIG. 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. FIGS. 1C to 1F are diagrams showing various examples of the tearing member used in the present invention. In the figure, 11, 11 ′ are optical cables, 12 are collective cores, 13 are press-wound tapes, 14 are sheaths, 15 are slot rods, 15a are slot grooves, 16 are tension members, 17 are optical fibers, and 18-18d are torn. The member is shown.

  As shown in FIG. 1 (A), an optical cable 11 according to the present invention is an optical cable having a structure in which the outer periphery of a collective core 2 in a state where a plurality of optical fibers are accommodated and bundled is covered with a sheath (also referred to as a jacket). Is targeted. The aggregate core 12 in the present invention is a state in which a plurality of optical fiber cores are aggregated using interposition or the like, and the outside thereof is bundled using a press-wound tape (also referred to as an upper winding tape), Or the thing of the state which accommodated the some optical fiber tape core wire etc. in the slot rod 15 shown to FIG.

  A slot-shaped optical cable 11 ′ shown in FIG. 1B is an optical cable that is frequently used as an optical cable for a trunk line laid in an underground pipeline or the like. The optical cable 11 ′ includes a slot rod (also referred to as a spacer rod) 15 made of a plastic material in which a tension member (also referred to as a tensile body) 16 is embedded and integrated at the center and a plurality of slot grooves 15 a are provided. The slot groove 15a of the slot rod 15 is formed in a spiral shape or an SZ shape. In the slot groove 15a, a plurality of optical fiber core wires or a tape-shaped optical fiber core wire (hereinafter including a tape core wire, Simply referred to as an optical fiber).

In a state where the optical fiber 17 is housed in the slot groove 15a, the press-wound tape 13 is applied to the outer periphery of the slot rod 15. This press-winding tape 13 holds the optical fiber 17 accommodated in the slot groove 15a so that it does not jump out, and absorbs water to stop water in the heat insulating layer when the sheath 14 is molded or in the optical cable. An agent may be added to function as a water absorbing layer. In addition, the presser winding tape 13 can be in a form of either a horizontal winding wound in a spiral shape or a longitudinally attached winding in the longitudinal direction, and is described above with the presser winding tape 13 applied. Thus, the aggregate core 12 is obtained.
The sheath 14 is formed to have a thickness of about 1.5 mm to 2 mm by extruding polyethylene or a flame retardant polyethylene resin on the outer periphery of the collective core 12.

  The present invention is characterized in that, in the above-described optical cables 11 and 11 ′, a tearing member 18 that reaches from the inner surface of the sheath to the outer surface of the sheath is embedded in at least one portion of the sheath 14 along the longitudinal direction of the cable. In the present invention, when the tearing member 18 reaches the outer surface of the sheath from the inner surface of the sheath, it means that the tearing member 18 is substantially in contact with the inner surface of the sheath and the outer surface of the sheath while being embedded in the sheath 14. The tearing member 18 may be provided at one location on the sheath 14, but may be provided at two locations facing each other.

  As shown in FIG. 1C, the tearing member 18 is preferably slightly protruded from the outer surface of the sheath 14 so that a part thereof is exposed. Thereby, the embedding position of the tearing member 18 can be clearly shown, and the drawing can be facilitated. In addition to the circular member 18a shown in FIG. 1C, the tearing member 18 has a rectangular member 18b shown in FIG. 1D, a triangular member 18c shown in FIG. Various shapes such as a trapezoidal member 18d shown in FIG. 1 (F) can be used. In any shape, by exposing a part of the tearing member from the outer surface of the sheath 14, it is possible to clearly indicate the embedded position of the tearing member, and from the sheath 14 of the tearing member. Can be easily pulled out.

  The tear members 18 to 18d can be made of a resin material different from the sheath 14 such as polyamide, polypropylene, or polyurethane, or can be made of a string or rope such as vinylon in advance. When the tear member 18 is a resin material, it can be formed simultaneously with the extrusion molding of the sheath 14 using a two-color molding technique. When a previously formed string or rope-like member is used for the tearing member 18, the sheath 14 is vertically attached so as to be in contact with the outer surface of the press-wound tape 13 of the assembly core 12 when the sheath 14 is formed, and the side surface portion is the sheath 14. It is buried so as to be covered with. By using a resin material different from the resin material of the sheath 14 as described above for the tearing member 18, the adhesive force with the sheath 14 is weak, and the tear member 18 can be easily peeled off from the sheath 14 when being pulled out.

FIG. 2 is a diagram for explaining an example in which the intermediate portion of the optical cable 11 is cut and peeled off. An optical cable in which a part of the circular tearing member 18a is exposed from the outer surface of the sheath 14 shown in FIG. I will explain it.
First, as shown in FIG. 2 (A), a cutter (for example, an electric cutter) 21 is used to make a circular cut 20 in the sheath 14 of the optical cable 11 and also cut the tearing member 18a. Next, as shown in FIG. 2B, an end portion of the cut tearing member 18a is picked out using a nipper or the like, and a tearing member 18a ′ having a predetermined length is pulled out along the longitudinal direction. The pull-out length of the tearing member 18a ′ is a sheath range to be peeled off (for example, a length range required for an intermediate branch, which is about 50 cm). By pulling out the tearing member 18 a ′, a tear 19 is generated in the sheath 14.

Next, as shown in FIG. 2C, a ring-shaped cut 20 is made by the cutter 21 so as to be connected to the end of the tear 19 generated by pulling out the tearing member 18a ′, and the pulled tearing member 18a ′ is also cut. In addition, when the tearing member 18a is provided at two places, as shown in FIG. 2 (C), both ends of the tear 19 produced by pulling out the tearing member 18a 'as a result of pulling out the other tearing member as well. It is only necessary that the two ring-shaped cuts 20 are connected to each other, so that the ring-shaped cuts 20 are first inserted at both ends of the sheath area to be peeled off, and then the tearing member 18a between the two ring-shaped cuts 20 at both ends is pulled out. May be.

Thereafter, as shown in FIG. 2 (D), the sheath piece 14a divided by the ring-shaped cut 20 and the tear 19 generated in the longitudinal direction is pulled from the surface of the collective core 12 by pushing the tear 19 open with a nipper or the like. Peel off and expose the press-wound tape 13 of the collective core.
Thereafter, the press-wound tape 13 of the aggregated core 12 that has been exposed is cut and removed, and the accommodated optical fiber is taken out.

  As described above, by pulling the tear member 18a out of the sheath 14, a tear 19 can be formed in the longitudinal direction of the sheath 14, and the sheath 19 can be easily peeled off by widening the tear 19. As a result, it is not necessary to cut with a cutter in the longitudinal direction of the sheath without using a conventional tear string, the sheath can be safely torn and workability can be improved. .

DESCRIPTION OF SYMBOLS 11,11 '... Optical cable, 12 ... Collective core, 13 ... Pressing winding tape, 14 ... Sheath, 14a ... Sheath piece, 15 ... Slot rod, 15a ... Slot groove, 16 ... Tension member, 17 ... Optical fiber, 18-18d ... tearing members, 19 ... tears, 20 ... circular cuts, 21 ... cutters.

Claims (5)

  An optical cable in which a sheath is coated on the outer periphery of a collective core in which a plurality of optical fibers are accommodated, and a tearing member that extends from the sheath inner surface to the sheath outer surface along the longitudinal direction of the sheath is provided. Optical cable.   The optical cable according to claim 1, wherein the tear member protrudes outward from the outer surface of the sheath.   The optical cable according to claim 1, wherein the tearing member is formed of a resin different from the sheath.   The optical cable according to any one of claims 1 to 3, wherein the tearing member is formed of a string formed in advance.   The aggregate core includes a slot rod that accommodates the plurality of optical fibers and a press winding tape that covers an outer periphery of the slot rod, and the tear member is in contact with the press winding tape. The optical cable according to any one of the above.

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