JP2011169932A - Optical cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical cable composed of a slot rod having a single groove to house a coated optical fiber which is taken out from the optical fiber cable without being damaged. <P>SOLUTION: The optical cable 10 has a single groove 12b to house a plurality of optical fiber ribbons along the longitudinal direction of the slot rod 12 and the outside of the slot rod 12 is coated with a sheath 11. Protection members 14 for covering and protecting the optical fiber ribbons 13 housed in the groove 12b are provided at every prescribed pitch in the groove 12b projecting from the groove 12b, and the slot rod 12 is coated with the sheath 11 while the protection members 14 are provided, and the parts at which the protection members 14 are coated with the sheath 11 project from the circumference. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical cable in which a plurality of optical fiber cores are housed in a groove extending in the longitudinal direction of a slot rod, and the outside of the slot rod is covered with a sheath.

  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 imaginary trunk optical cable to a subscriber's house. For example, an optical fiber is pulled down to a subscriber's home, 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 core. Are connected using fusion splicing or an optical connector.

  As the trunk optical cable, for example, an optical cable using a slot rod having a plurality of grooves for accommodating optical fiber ribbons as disclosed in Patent Document 1 is frequently used. In this optical cable, a plurality of tape core wires are accommodated in a slot of a slot rod, and the outer side thereof is covered with a sheath (also referred to as a jacket) by extrusion molding. In order to draw an optical fiber from a middle portion of a trunk optical cable made of such an optical cable to a subscriber's house, etc., it is necessary to take out the optical fiber core housed in the cable. Is removed to a certain length (about 30 to 50 cm). Specifically, two cuts are made in the circumferential direction of the sheath of the optical cable with a blade, and further, a cut is made in the longitudinal direction so that the two cuts are tied, and the cut part is opened with a tool such as a nipper. Remove the sheath. Thereby, an internal tape core wire can be taken out.

JP-A-8-220393

  The conventional optical cable described above has a plurality of grooves in a slot rod and has 100 or more optical fibers. However, there is a demand for an optical cable having a relatively small number of cores of 100 or less. In this case, as shown in FIG. 3, it is assumed that the groove is one slot rod. 3A shows the appearance of the optical cable, and FIG. 3B shows a cross section (for example, AA cross section) at an arbitrary position of the optical cable in FIG. 3A. In the illustrated optical cable 1, a slot rod (also referred to as a spacer) 2 having a groove 2 a extending in the longitudinal direction is used. In the optical cable 1 using a slot rod with one groove, the slot rod 2 in which a plurality of tape core wires 3 are housed in the groove 2a is covered with a sheath 4 formed by extrusion molding, as in the conventional case. Is done.

  However, in the optical cable 1 of FIG. 3 described above, when the tape core wire 3 in the cable is taken out for intermediate branching, it is necessary to make a cut in the sheath 4 with a cutter such as a nipper. At this time, in the vicinity of the opening 2b of the groove 2a of the slot rod 2, the cutter may come into contact with the tape core wire 3 (optical fiber core wire) to damage the core wire.

  The present invention has been made in view of the circumstances as described above, and is an optical cable including a slot rod having a single groove for accommodating an optical fiber core wire (including a tape core wire), and the optical cable to the optical fiber. An object of the present invention is to provide a cord that does not damage the core when the core is taken out.

The optical cable of the present invention is an optical cable in which a single groove for housing a plurality of optical fiber cores is provided along the longitudinal direction of the slot rod, and the outside of the slot rod is covered with a sheath. A protective member that covers and protects the plurality of optical fiber cores housed is provided in the groove so as to protrude from the groove, and the slot rod is covered with a sheath in a state where the protective member is provided, A portion in which the protective member is covered with the sheath protrudes from the periphery.
Said predetermined space | interval is length required for an intermediate branch, for example, is 25-50 cm.

  According to the optical cable of the present invention, the portion protected by the protective member of the optical fiber housed in the groove of the slot rod protrudes even in the state covered with the sheath. If a break is made as a mark, the optical fiber core housed in the groove will not be damaged.

It is a figure explaining the outline of the optical cable of this invention. It is a figure explaining an example of the manufacturing apparatus of the optical cable of this invention. It is a figure which shows an example of the optical cable explaining the problem which should be solved of this invention.

  FIG. 1A is an external view showing an example of the optical cable of the present invention, FIG. 1B shows a BB cross section of the optical cable of FIG. 1A, and FIG. The CC cross section of the optical cable of A) is shown.

  The optical cable of the present invention is configured by covering the outside of a slot rod 12 containing an optical fiber ribbon 13 with a sheath 11 made of a thermoplastic resin such as polyethylene, as exemplified by reference numeral 10 in FIG. As illustrated in FIG. 1B, the slot rod 12 is formed by embedding and integrating a tension member (strength member) 12a and providing a single groove 12b, and is formed of a resin material such as polyethylene. . The groove 12b extends along the longitudinal direction of the slot rod 12, and a plurality of (five in the example in the figure) optical fiber ribbons (hereinafter referred to as the following) inserted through the opening 12c. 13 (referred to as a tape core) is stored. Note that the tape core wire 13 is formed by aligning a plurality of optical fiber core wires in a line and integrating them in a tape shape.

Further, as shown in FIG. 1C, the optical cable 10 covers and protects the tape core wire 13 accommodated in the groove 12b while closing the opening 12c (see FIG. 1B) of the groove 12b of the slot rod 12. The protective member 14 is provided at predetermined intervals in the longitudinal direction. The predetermined interval is a length necessary for the intermediate branch, and is, for example, 25 to 50 cm.
The protective member 14 has a length of about 2 cm, and protrudes from the groove 12b at a stage where the protective member 14 is provided in the groove 12b, that is, before the slot 11 is covered with the sheath 11. As shown in FIG. 1A, after the covering, the portion covered with the protective member 14 protrudes from the surrounding portion to form a convex portion 11a. Therefore, the operator can know in which part of the optical cable 1 the protective member 14 is provided.

  In order to take out the tape core wire 13 from the optical cable 10, for example, first, a circumferential cut passing through the convex portion 11a is made in the sheath 11, and a circumferential cut passing through the adjacent convex portion 11a is made. Put in. Further, the sheath 11 is cut in the longitudinal direction so that these two cuts are connected. At this time, since there is a groove 12b in which the tape core wire 13 is accommodated below the straight line connecting the convex portions 11a, the longitudinal cut is made to avoid the straight line. Then, the sheath 11 is removed by opening the cut portion with a tool such as a nipper. Thereby, the internal tape core wire 13 can be taken out.

  As described above, in the optical cable 10, the portion where the tape core wire 13 housed in the groove 12 b of the slot rod 12 is protected by the protective member 14 protrudes from the surrounding portion even in the state covered with the sheath 11. The convex portion 11 a is recognized from the appearance of the optical cable 10. Therefore, if the cut is made with the convex portion 11a as a mark when the sheath 11 is removed, the tape core wire 13 accommodated in the groove 12b is not damaged.

Further, in the optical cable 10, by providing the protective members 14 at predetermined intervals, the tape core wire 13 can be taken out from the slot rod 12 without removing the protective member 14 after the sheath 11 is removed. Are better. Furthermore, since it is provided at predetermined intervals as described above, the optical cable 10 can be easily bent even if the protection member 14 is provided.
As a material for the protective member 14, an elastomer material that is not softened by heat when forming the sheath 11 and has elasticity is suitable. If the material has elasticity, a large lateral pressure is not applied to the tape core wire 13 in a state where the material is covered with the sheath 11, and an increase in transmission loss of the optical fiber can be suppressed.

FIG. 2 is a schematic diagram illustrating an example of an apparatus for manufacturing the optical cable 10 of FIG.
As illustrated by the reference numeral 20 in FIG. 2A, the optical cable 10 manufacturing apparatus includes a slot rod feeding portion 21, a plurality of tape core wire feeding portions 22, a collecting portion 23, and a protective member mounting portion 24. The covering portion 25, the cooling portion 26, and the winding portion 27 are arranged in order.

  The slot rod feeding portion 21 feeds the slot rod 12 toward the collecting portion 23, and the tape core wire feeding portion 22 feeds the tape core wire 13 toward the collecting portion 23. The assembly portion 23 is arranged so that a plurality (5 in the illustrated example) of the tape core wires 13 are aligned and overlapped in the groove 12b of the slot rod 12 (see FIGS. 1B and 1C). The slot rod 12 and the tape core wire 13 inserted into the portion 23 are aligned and sent to the protective member mounting portion 24. Thereby, the tape core wire 13 is accommodated in the groove 12b.

  The protective member attaching portion 24 attaches a pre-molded protective member 14 having a length of about 2 cm, which matches the size of the groove 12b, to the groove 12b in which the tape core wire 13 is accommodated at predetermined intervals. The covering portion 25 covers the slot rod 12 to which the protection member 14 is attached with the sheath 11. The covering portion 25 defines a shape of the sheath 11 (forms), and a thermoplastic resin as a material of the sheath 11. And an extruder 25b that heats the material and supplies it to the crosshead 25a. The cooling unit 26 cools the sheath 11 formed around the slot rod 12 by the covering unit 25. The winding unit 27 winds the completed optical cable 10 passing through the cooling unit 26.

  In the above example, a plurality of optical fiber cores are housed in a tape shape, but a plurality of single fiber optical fibers can also be housed.

DESCRIPTION OF SYMBOLS 10 ... Optical cable, 11 ... Sheath, 11a ... Convex part, 12 ... Slot rod, 12b ... Groove, 13 ... Tape core wire, 14 ... Protection member, 20 ... Manufacturing apparatus, 21 ... Slot rod feeding part, 22 ... Tape core wire Feeding part, 23 ... collecting part, 24 ... protective member attaching part, 25 ... covering part, 25a ... crosshead, 25b ... extruder, 26 ... cooling part, 27 ... winding part.

Claims (2)

A single groove that houses a plurality of optical fiber cores along the longitudinal direction of the slot rod is provided, and an optical cable is formed by covering the outside of the slot rod with a sheath,
A protective member that covers and protects the plurality of optical fiber cores housed in the groove is provided in the groove at predetermined intervals so as to protrude from the groove,
The slot rod is covered with the sheath in a state where the protection member is provided;
An optical cable characterized in that a portion of the protective member covered with the sheath protrudes from the periphery.   The optical cable according to claim 1, wherein the predetermined interval is 25 to 50 cm.

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