JP2007272006A - Optical fiber cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fiber cable capable of reducing damages caused by cicadas laying eggs as much as possible and allowing a jacket to be easily peeled off. <P>SOLUTION: The optical fiber cable has optical fiber cores 2 and tensile strength wires 3 arranged in parallel with the optical fiber cores 2 in one plane 1A, coats the optical fiber cores and the tensile strength wires with one jacket 4, which has a pair of outside surfaces 4A parallel with the plane 1A, and forms jacket cutting notch grooves 5 extended in the axial direction of the optical fiber cores on the outside surfaces; where each notch groove 5 is extended from an aperture part 5A on the outside surface 4A into the jacket at a right angle to the plane 1A or in a direction separated from the optical fiber core 2 on a cross section vertical to the axial line and then bent and extended so as to be approached to the optical fiber core 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical fiber cable, and more particularly, to an optical fiber cable in which an optical fiber core wire and a tensile wire are covered with a single jacket, and a notch for tearing the jacket is formed on the outer surface of the jacket. .

  A cable drawn from an aerial optical fiber cable to each home or office is called a drop cable.

  Usually, the drop cable has a structure in which a single-core or multiple-core optical fiber and a tensile body positioned in parallel so as to sandwich the core are covered with a jacket. In order to make it easy to take out the internal optical fiber when connecting the cable to the device, the outer peripheral surface of the coating is provided with a notch for cutting with a V-shaped cross section extending in the longitudinal direction of the cable at a position directly above the optical fiber. A groove (notch) is formed.

  On the other hand, there are many cases in which the inner optical fiber core wire is disconnected due to the spawning behavior of such a cable laid.

  In particular, if the egg laying tube is pierced into the jacket at the deep part of the notch groove, the distance to the optical fiber core is short, or the notch groove is directed from the opening to the optical fiber core to facilitate tearing of the jacket. Therefore, there is a high risk that the laying tube reaches the optical fiber core, and the optical fiber is damaged by the laying tube.

  Therefore, in Patent Document 1, as shown in FIG. 4 of the accompanying drawings, a notch groove 52 opened in the outer peripheral surface of the cable jacket 51 is provided with an optical fiber core 53 and the optical fiber core so as to sandwich the optical fiber core 53. The deepest portion 52A of the notch groove 52 is shifted from the position of the optical fiber core wire 53 at a position on the outer jacket outer surface 55 parallel to a plane including the tensile body 54 positioned parallel to the line. Proposed.

According to Patent Document 1, even if the optical fiber core wire 53 is not positioned directly below the deepest portion of the cutout groove and a semi-vibration tube is pierced into the cutout groove, the spawn tube is traumatic to the optical fiber core wire 53. The risk of giving is reduced.
JP-A-2002-090593

  In the cable according to Patent Document 1, since the opening position of the notch groove is shifted from the position directly above the optical fiber core (the position closest to the optical fiber core), the risk that the egg laying tube damages the optical fiber core is reduced. .

  However, on the other hand, in the optical fiber cable, it is desirable that the position of the notch groove is closer to the position of the optical fiber core wire in order to facilitate the work of taking out the optical fiber core wire from the inside of the coating when connected. Therefore, in consideration of such circumstances, the notch groove cannot be so far from the position of the optical fiber core wire. In Patent Document 1, although the deepest part of the notch groove is deviated from the position of the optical fiber core, it is located as close as possible to the core position in consideration of the ease of peeling of the jacket, so that the above damage is possible. It is not separated enough to be safe enough for sex.

  Moreover, since it forms in the V-shape symmetrical with the notch groove | channel of the said patent document 1, there exists a high possibility that an egg-laying tube will stab in the orthogonal | vertical direction with respect to the outer surface of a jacket, As a result, the vicinity of optical fiber core wire In this respect, it is hard to say that it is sufficiently safe.

  In view of such circumstances, it is an object of the present invention to provide an optical fiber cable having a jacket that reduces the damage caused by cicada egg laying as much as possible and that facilitates the peeling operation of the jacket.

  An optical fiber cable according to the present invention has an optical fiber core wire and a tensile wire arranged parallel to the optical fiber core wire in one plane, and the optical fiber core wire and the tensile wire are formed by a single jacket. The outer cover has a pair of outer surfaces parallel to the one plane, and a notch groove for cutting the outer shell extending in the axial direction of the optical fiber core wire is formed on the outer surface.

  In such an optical fiber cable, according to the present invention, the cutout groove has a cross section perpendicular to the axis, and has a jacket in a direction perpendicular to the one plane from the opening on the outer surface or away from the optical fiber core. After extending inward, it is bent and extends so as to approach the optical fiber core wire.

  In the optical fiber cable of the present invention having such a configuration, the opening of the notch groove can be positioned far from the optical fiber core wire, and the opening is perpendicular to the one plane or near the outer surface of the jacket. Since it is facing away from the optical fiber core, even if the cicada pierces the lay tube at the opening, its position is away from the optical fiber core and the direction is not in the optical fiber core direction Therefore, there is no possibility of damaging the optical fiber core wire. Furthermore, since the cutout groove is bent in a different direction inside the outer cover and approaches the optical fiber core wire, the outer cover is easily peeled off.

  In the present invention, the notch groove preferably has a groove width smaller in the groove than in the opening. Since the groove width inside the groove is narrow, the cicada itself is prevented from entering the groove. Moreover, even if the groove width inside the groove is narrow for peeling of the outer cover, it is possible to secure the ease of peeling without any trouble.

  In the present invention, the opening of the notch groove is spaced apart from the position of the optical fiber core, and the opening is perpendicular to the outer surface of the jacket parallel to a plane including the optical fiber core and the tensile strength line. Since it is formed so as to be bent and approach the optical fiber core after extending, even if a cicada pierces the laying tube, the optical fiber core is not damaged. Even if the cicada pierces the laying tube deep in the notch groove, in this case, the laying tube will be stabbed at a position far from the optical fiber core, and the direction is perpendicular to the jacket and the optical fiber core The direction in which the cicada pierces the laying tube is guided in a direction perpendicular to the one plane, so that the optical fiber is not damaged. Also, even if the cicada pierces the egg-laying tube at a position directly above the optical fiber core, not at the opening of the notch groove, the inside of this position is thickly covered with a jacket, so the optical fiber core There is a sufficient distance until the optical fiber core wire is not damaged. Furthermore, in the present invention, the notch groove extends toward the optical fiber core, and the notch groove can be extended to a position directly above the optical fiber core. Can be easily done.

  Embodiments of the present invention will be described below with reference to FIGS. 1 and 2 of the accompanying drawings.

  An optical fiber cable 1 extending long in a direction perpendicular to the paper surface in FIG. 1 has two (two-core) optical fiber core wires 2 and two tensile strength wires 3 positioned so as to sandwich them, The optical fiber core wire 2 and the tensile strength wire 3 are covered and protected and supported by a sheath 4 made of an electrical insulating material. The optical fiber core wire 2 and the tensile strength wire 3 are arranged such that their axes are located on one plane 1A.

  As the tensile strength wire, for example, an iron wire, a steel wire, or FRP is used, and as the jacket material, for example, polyethylene, PVC (polyvinyl chloride), or the like is used.

  The outer sheath 4 has an outer shape in a cross section perpendicular to the axes of the optical fiber core wire 2 and the tensile strength wire 3, and an outer surface 4A parallel to the one plane 1A, as shown in FIG. It has a rectangular shape formed with the outer end surface 4B. In view of the relationship in which the optical fiber core wire 2 and the tensile strength wire 3 are arranged on the one plane 1A, in FIG. 1, the outer surface 4A parallel to this is longer than the outer end surface 4B.

  A cutout groove 5 having an opening 5A in the outer surface 4A is formed in the outer cover 4 so as to extend in a direction perpendicular to the paper surface. This notch groove 5 is provided in two places located on the diagonal of a rectangular cross section in FIG.

  The cutout groove 5 has an opening 5A located as close as possible to the end of the outer surface 4A, that is, as far as possible from the center line position near the outer surface 4B, and extends in a direction perpendicular to the outer surface 4A. The groove interior 5 </ b> B extends toward the optical fiber core wire 2.

  The tip of the groove interior 5B reaches just above the optical fiber core wire 2. In the present embodiment, the groove width of the cutout groove 5 is narrower than the opening 5A as a preferred form.

  In use of such an optical fiber cable 1, when the optical fiber cable 1 is used, an operator tears the groove inside 5 </ b> B of the notch groove 5 to reach the optical fiber core wire 2 to connect the optical fiber core wire 2. The fiber core wire 2 is exposed and connected to a predetermined cable or device.

  In addition, when the optical fiber cable 1 is installed in the air with a utility pole or the like, it may be damaged by a semi, especially a bear jemi. Kumazemi often stays in fiber optic cables and lays eggs. The egg-laying tube is inserted into the jacket 4 of the optical fiber cable.

  In the optical fiber cable 1 of the present embodiment, it is conceivable that the bearfish pierces the egg-laying tube at the opening 5A where it is easy to stay. Since the opening 5 </ b> A is located near the end of the outer surface 4 </ b> A of the jacket 4, it is far from the optical fiber core 2 and the laying tube does not reach the optical fiber core 2. In addition, since the opening 5A extends in a direction perpendicular to the one plane 1A, the laying tube is guided so as to be pierced in this direction, so that the laying tube is directed toward the optical fiber core wire. There is nothing. Also from this point, the optical fiber core wire 2 is not damaged by the laying tube. If the notch groove is provided so that the opening is located on the outer end surface 4B as shown in FIG. 3 because it is simply the farthest from the optical fiber core as shown in FIG. 3, the opening is formed on the outer end surface. Since it faces in the direction perpendicular to 4B, that is, toward the optical fiber core wire, the egg-laying tube faces in that direction, which is not preferable. Therefore, the position of the opening should be on the outer surface 4A as far as possible from the optical fiber core as in this embodiment.

  Furthermore, in the present embodiment, as a preferred form, the groove interior 5A has a groove width narrower than that of the opening 5A, and therefore, the bearfish does not allow the body to enter the groove interior 5B. Therefore, the bearfish will lay eggs in the opening 5A.

  Even if the koma-zemi stays on the outer surface 4A of the jacket 4 at the position closest to the optical fiber core 2, that is, the position just above the optical fiber core 2 in FIG. Therefore, there is a sufficient distance from the outer surface 4A to the optical fiber core 2 so that the laying tube does not reach the optical fiber core 2.

  In the present embodiment, the notch groove 5 is not limited to the position and form indicated by the solid line in FIG. 1, and various changes can be made. For example, the notch groove 5 may be provided on the same side in the left-right direction instead of the diagonal position in the figure. You may consist of the notch groove 5 shown as the continuous line in the upper right part, and the notch groove 5 'shown as the dashed-two dotted line in the lower right part. Further, the groove inner portion 5 ″ B may be inclined toward the optical fiber core 2 instead of being bent at a right angle like a cutout groove 5 ″ indicated by a two-dot chain line in the lower left portion.

  Furthermore, for example, the opening 5A of the notch groove 5 shown in the upper right part of FIG. 1 is formed so as to be inclined away from the optical fiber core wire 2 without extending at right angles to the outer surface 4A. May be. Also in this case, the inside of the groove can be bent and extended as shown by 5B or 5 ″ B.

  In the present invention, the optical fiber core wire is not limited to the two cores illustrated in FIG. 1, and may be a single core or a plurality of core wires of three or more cores. It may be a tape core 2 'in which the cores are collected with a tape.

It is sectional drawing in the surface orthogonal to the axis line of the optical fiber cable of one Embodiment of this invention. It is sectional drawing of the optical fiber cable of other embodiment. It is sectional drawing of the optical fiber cable which shows the unpreferable form contrasted with this invention. It is sectional drawing of the conventional optical fiber cable.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical fiber cable 1A One plane 2 Optical fiber core wire 3 Tensile wire 4 Outer sheath 4A Outer side surface 5 Notch groove 5A Opening 5B Inside groove

Claims (2)

  An optical fiber core wire and a tensile wire arranged in parallel to the optical fiber core wire in one plane, and the optical fiber core wire and the tensile wire are covered with one outer sheath, In an optical fiber cable having a pair of outer surfaces parallel to a plane, and having a notch groove for cutting the outer shell extending in the axial direction of the optical fiber core wire, the notch groove is formed with respect to the axis. In a vertical cross section, it extends from the opening on the outer surface to the outer surface in a direction perpendicular to the one plane or away from the optical fiber core, and then bent so as to approach the optical fiber core. An optical fiber cable characterized by   The optical fiber cable according to claim 1, wherein the notch groove has a groove width smaller than that of the opening in the groove.

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