JP2007148181A - Optical fiber cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fiber cable that has a superior easiness for taking out coated optical fibers, in a structure in which a protective member is arranged on both sides of the coated optical fibers. <P>SOLUTION: The optical fiber cable 1 is equipped with coated optical fibers 3, two tape-like protective members 8a, 8b arranged in parallel on both sides of the coated optical fibers 3, and a cable sheath 2 covering the coated optical fibers 3 and the two protective members 8a, 8b. In the optical fiber cable 1, ripping notches 7 are formed in the longitudinal direction of the cable sheath 2 for the purpose of taking out the coated optical fibers 3. The protective members 8a, 8b are composed such that their respective one end mutually situated diagonally across the coated optical fibers 3 is each arranged near the end of the coated optical fibers 3 and that the width of the protective members 8a, 8b is designed to be wider than the width of the coated optical fibers 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical fiber cable such as a drop cable or an indoor cable provided with a tear notch for taking out an optical fiber.

  The drop cable is used for pulling an optical fiber, and a notch having a V-shaped cross section extending continuously in the longitudinal direction is provided at a substantially central portion of a cable jacket (sheath) constituting the optical fiber cable. Since the apex of the V-shape is close to the optical fiber core, it is possible to take out the optical fiber core in the sheath by manually tearing the sheath from the notch without using a special tool. For example, Patent Document 1 discloses a structure of an optical fiber cable in which a tensile body and an optical fiber core wire are accommodated in a sheath.

  In the optical fiber cable having the above structure, when the optical fiber core wire is taken out by opening the notch portion, a cut extending from the notches on both sides may pass through the same side of the optical fiber core wire. At this time, there is a problem that the optical fiber core wire is taken into the sheath remaining in the U-shaped cross section, and the take-out operation becomes complicated. Countermeasures such as shifting the position of the notch and changing the arrangement of the optical fiber core wire. Various are taken.

In addition, among such optical fiber cables, there are known ones provided with a protective material for protecting the optical fiber core wire in order to improve the reliability with respect to the damage caused by the cicada oviduct (for example, , See Patent Document 2). This is because, in the summer, the cicada may pierce the egg-laying tube into the notch and damage the optical fiber core contained therein. To prevent this, a protective material is provided to prevent cicada laying. The tube is blocked.
JP 2003-295011 A JP 2002-90591 A

  FIG. 9 is a diagram showing the structure of a conventional optical fiber cable disclosed in Patent Document 2. As shown in FIG. In the figure, reference numeral 100 denotes an optical fiber cable. The optical fiber cable 100 includes an optical fiber core wire 101, a tensile body 102 disposed in parallel with the optical fiber core wire 101 interposed therebetween, an optical fiber core wire 101, and a tensile strength. A sheath 103 that covers the body 102, a tear notch 104 formed in the longitudinal direction of the sheath 103, and two protective members 105a and 105b arranged in parallel on both sides of the optical fiber core wire 101. ing. Thus, by arranging the protective members 105a and 105b, it is possible to protect the optical fiber core wire 101 from the semi-nulling tube.

  However, when the protective materials 105a and 105b for semi-semiconductors are provided on both sides of the optical fiber core wire 101 in the arrangement as described above, a break due to tearing from the tear notch 104 passes through the same side of the optical fiber core wire 101. As a result, the optical fiber core wire 101 may be confined in the sheath 103 together with the protective members 105a and 105b. Since the protective members 105a and 105b are made of a highly rigid material because of the required performance, it is difficult to take out the optical fiber core wire 101 inside.

  The present invention has been made in view of the above-described circumstances, and is an optical fiber cable having a structure in which protective materials are arranged on both sides of an optical fiber core, and is excellent in the ability to take out the optical fiber core. The purpose is to provide.

  An optical fiber cable according to the present invention includes an optical fiber core, two tape-shaped protective members arranged in parallel on both sides of the optical fiber core, and a sheath covering the optical fiber core and the two protective members. With. A tear notch for taking out the optical fiber core is formed in the longitudinal direction of the sheath, and the two protective members have one end opposite to the end of the optical fiber core across the optical fiber core. The width of the two protective members is wider than the width of the optical fiber core.

  According to the present invention, when the optical fiber cable is pulled out by tearing the notch of the optical fiber cable, one end of the protective material is integrated with the sheath and separated from the optical fiber cable. It can be easily taken out.

  FIG. 1 is a diagram illustrating an example of an optical fiber cable according to an embodiment of the present invention. In the figure, 1 is an optical fiber cable, and the optical fiber cable 1 includes a cable sheath 2, an optical fiber core wire 3, a tensile body 4, a support wire 5, a support wire sheath 6, a tear notch 7, and a protective material 8a, 8b. The optical fiber cable 1 includes, for example, an optical fiber core wire 3 formed of two four-core tape core wires at a substantially central portion of the cable sheath 2, and the optical fiber core wire 3, the strength member 4, and the protection by the cable sheath 2. The material 8a, 8b is integrally covered. Here, a cross section of the optical fiber cable 1 when viewed with the support wire 5 facing upward is shown.

  The cable sheath 2 is formed of a thermoplastic resin such as polyvinyl chloride or polyethylene. The optical fiber core 3 used in the present invention is, for example, an optical fiber strand in which a glass fiber is protected with a coating resin or a tape core wire in which a plurality of optical fiber strands are formed in a tape shape. The strength member 4 is formed of a steel wire, FRP, or the like, and the support wire 5 is formed of a steel wire or the like. The support wire sheath 6 is formed by integral molding with the cable sheath 2 using a thermoplastic resin such as polyvinyl chloride or polyethylene. The protective members 8a and 8b are arranged in parallel on both sides of the optical fiber core 3 on the side where the slit notch 7 is formed, and are formed of two pieces of tape-like plastic or metal.

  The tear notch 7 is formed in a V-shaped cross section or a trapezoidal shape in the longitudinal direction of the cable sheath 2. The optical fiber core wire 3 in the optical fiber cable 1 is connected to a home appliance. At this time, the cable sheath 2 is torn and the notch 7 is torn by hand, and the inner optical fiber core wire 3 is taken out. By providing the slit notch 7, the optical fiber core wire 3 can be easily taken out without requiring a special tool.

  As shown in FIG. 1, the two protective members 8 a and 8 b have a width W1 wider than a width W2 of the tape core wire 3, and one end at a position diagonal to each other across the tape core wire 3. Located near the end of line 3. Specifically, the two protective members 8a and 8b cover the side surface of the tape core wire 3, while the lower end of one protective member 8a is disposed near the lower end of the tape core wire 3, and the other protective member 8b The upper end is disposed near the upper end of the tape core wire 3. Or, conversely, the upper end of one protective member 8 a may be disposed near the upper end of the tape core 3, and the lower end of the other protective member 8 b may be disposed near the lower end of the tape core 3.

  By configuring in this way, the portion connecting the lower end of the tape core 3 from the lower end of the protective material 8a and the portion connecting the upper end of the tape core 3 from the upper end of the protective material 8b are easily cut in the horizontal direction in the figure. be able to.

  When this optical fiber cable 1 is torn apart so as to separate the tear notches 7 on both sides, the cut C entering from the tear notch 7 on the left side of the figure spreads up and down along the side surface of the protector 8a, and the protector 8a It spreads so that the lower end of the optical fiber core wire 3 may be opened from the lower end. On the other hand, the cut C that has entered from the slit notch 7 on the right side of the figure spreads so as to open the upper end of the optical fiber core wire 3 from the upper end of the protective material 8b. Since the protective members 8a and 8b and the optical fiber core wire 3 are not bonded, the central portion of the optical fiber cable 1 including the optical fiber core wire 3 is not wrapped by the cable sheath 2. Thereby, the optical fiber core wire 3 can be taken out easily.

  FIG. 2 is a diagram showing another example of the optical fiber cable 1 of the present invention. In this example, the slit notch 7 of the optical fiber cable 1 having the structure shown in FIG. 1 is located at a position close to the ends of the protective members 8a and 8b (the lower end of the protective member 8a and the upper end of the protective member 8b in the figure). They are staggered. Since the ends of the protective members 8a and 8b and the slit notch 7 are close to each other, when the slit notch 7 is opened, the side surfaces of the protective members 8a and 8b widen and the optical fiber cores from the protective members 8a and 8b almost simultaneously. The optical fiber core wire 3 can be taken out more easily by extending to the end of the wire 3.

  As the protective material 8a and 8b described above, a high-hardness plastic tape, a metal tape, or a tape made of a composite material thereof that is difficult to pass through a semi-vibrating oviduct can be used. For example, polyethylene terephthalate or polycarbonate can be suitably used as the plastic material, and stainless steel or aluminum can be suitably used as the metal material. In addition, the thickness of the protective material 8a, 8b is preferably at least 0.05 mm or more in order to reduce the trauma to the cicada oviposition tube.

  The illustrated optical fiber cable 1 accommodates two four-fiber ribbons in which four optical fibers having a thickness of about 0.32 mm and a width of about 1.10 mm are coated with an ultraviolet curable resin. As the core 3, various core structures such as a single core and a tape core can be used as will be described later, and the number of the cores 3 is also arbitrary.

  Further, the width W1 (in the height direction in the figure) of the protective members 8a and 8b is set so that at least the optical fiber core 3 in contact with the protective members 8a and 8b is in order to cope with damage to the optical fiber core 3 due to a semi-conductor. It is configured wider than the width W2. The width W1 of the protective material 8a, 8b is set so that the cable sheath 2 is less likely to be broken at one end of the optical fiber core 3 (the upper end of the protective material 8a and the lower end of the protective material 8b in the figure). It is desirable that the width is equal to or larger than twice the width W2 of the optical fiber core wire 3.

  Here, the strength member 4 is not necessarily required, and the cable sheath 2 at the upper and lower portions of the optical fiber core wire 3 only needs to have a strength that allows tearing using the tear notch 7. That is, it is only necessary that the cross section of these portions is wide like a dumbbell and can give a sufficient tearing force to the tear notch 7. The tear notch 7 is not necessarily provided on the surface of the cable sheath 2. For example, a substantially triangular space having a vertex that forms a tear point may be provided in the cable sheath 2.

  FIG. 3 is a diagram showing another example of the optical fiber cable 1 of the present invention. Thus, the ends of the protective members 8a and 8b that are diagonal to each other across the optical fiber core 3 (the lower end of the protective member 8a and the upper end of the protective member 8b in the figure) are the ends of the optical fiber core 3. Further, the other ends of the protective members 8a and 8b (the upper end of the protective member 8a and the lower end of the protective member 8b in the figure) are extended to the vicinity of the strength member 4, and the optical fiber core wires of the protective members 8a and 8b It is good also as a structure which embeds the part which is not in contact with 3 in the inside of the cable sheath 2. FIG.

  When the cable sheath 2 is torn from the notch 7 in the optical fiber cable 1 shown in FIG. 3A, the other ends of the protective members 8a and 8b (in the drawing, the protective member 8a are shown in FIG. 3B). And the lower end of the protective material 8b are integrated with the cable sheath 2 and away from the optical fiber core 3, so that the processing of the protective materials 8a and 8b after the optical fiber core 3 is taken out becomes easy.

  In the vicinity of the strength member 4, the strength of the strength member 4 is high and the thickness of the cable sheath 2 is thick, so that the deformation amount of the cable sheath 2 is small compared to the middle portion of the optical fiber cable 1. For this reason, the protective materials 8a and 8b are not easily peeled off from the cable sheath 2, and the protective materials 8a and 8b can be removed together with the cable sheath 2.

  The optical fiber cable 1 exemplified so far is a cable having a structure suitable for aerial laying provided with the support wire 5. However, the improvement of the take-out property of the optical fiber core, which is the main effect of the present invention, is achieved by the slit notch. The present invention can be applied to optical fiber cables having various structures for taking out a built-in optical fiber core wire. Examples of such optical fiber cables are shown in FIGS. 4 to 8 below.

  FIG. 4 is a diagram showing another example of the optical fiber cable 1 of the present invention. This example shows a configuration example used as an indoor cable in which a support line portion (a portion including the support wire 5 and the support wire sheath 6) is removed from the optical fiber cable 1 illustrated in FIGS. The optical fiber cable 1 includes a cable sheath 2, an optical fiber core wire 3, a strength member 4, a tear notch 7, and protective materials 8a and 8b.

  5 to 8 are diagrams showing examples of the optical fiber cable 1 in which the core configuration of the optical fiber core 3 is different. FIG. 5 shows an optical fiber core wire 3 composed of a single core. FIG. 6 shows an optical fiber core wire 3 composed of two cores. FIG. 7 shows an optical fiber core 3 composed of a single four-core tape core. FIG. 8 shows an optical fiber core wire 3 composed of a plurality of cores. As described above, the two protective members 8a and 8b are wider than the width (or diameter) of the tape core wire 3, and one end of the tape core wire 3 at a diagonal position with the tape core wire 3 interposed therebetween is the tape core wire. The optical fiber core wire 3 having various core wire structures such as a single core wire and a tape core wire can be used, and the number of housings is arbitrary.

  In these examples, when a force is applied so as to separate the strength member 4, the thickness of the material of the cable sheath 2 is thin at a position near the end faces of the protective members 8 a and 8 b as shown by a broken line C in FIGS. Therefore, the cable sheath 2 is cut from the thinned position of the tearing notch 7 having a flat bottom, and the optical fiber core wire 3 is taken out. As shown in these examples, the slit notch 7 does not necessarily have an acute tip. Those with an acute tip have a low force when removing the cable sheath 2 due to stress concentration, while those with a curved or flat bottom surface of the tear notch 7 are notched due to the ironing during installation. 7 is advantageous in that it is difficult to break.

  In the above description, the cable structure in which the optical fiber core wire and the protective material are in direct contact with each other is shown as a specific example. However, even if there is an inclusion in this space (between the optical fiber core wire and the protective material). Good. The upper and lower ends of the optical fiber core are respectively positioned in the vicinity of the upper and lower ends of one protective material, and the optical fiber core and the sheath are connected so that these ends are connected when tearing by a notch. If it is separated, the effect of the present invention can be obtained. Examples of the inclusion include a cushioning material such as a thin-film nonwoven fabric or yarn arranged to improve transmission characteristics such as wraparound of the sheath material and lateral pressure characteristics.

As described above, according to the present invention, when the optical fiber cable is pulled out by tearing the notch of the optical fiber cable, one end of the protective material is integrated with the sheath and separated from the optical fiber cable, Only the optical fiber core wire can be easily taken out.
Note that the present invention is not limited to the above-described embodiments, and it is obvious that the embodiments can be appropriately changed within the scope of the technical idea of the present invention. In addition, the number, position, shape, and the like of the constituent members are not limited to the above-described embodiment, and can be set to a suitable number, position, shape, and the like in practicing the present invention.

It is a figure which shows an example of the optical fiber cable which concerns on embodiment of this invention. It is a figure which shows the other example of the optical fiber cable of this invention. It is a figure which shows the other example of the optical fiber cable of this invention. It is a figure which shows the other example of the optical fiber cable of this invention. It is a figure shown about the example of the optical fiber cable from which the core wire structure of an optical fiber core wire differs. It is a figure shown about the other example of the optical fiber cable from which the core wire structure of an optical fiber core wire differs. It is a figure shown about the other example of the optical fiber cable from which the core wire structure of an optical fiber core wire differs. It is a figure shown about the other example of the optical fiber cable from which the core wire structure of an optical fiber core wire differs. It is a figure which shows the structure of the conventional optical fiber cable currently disclosed by patent document 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,100 ... Optical fiber cable, 2 ... Cable sheath, 3,101 ... Optical fiber core wire, 4,102 ... Strength body, 5 ... Support wire, 6 ... Support wire sheath, 7,104 ... Rupture notch, 8a, 8b, 105a, 105b ... protective material, 103 ... sheath.

Claims (4)

An optical fiber core; two tape-shaped protective members arranged in parallel on both sides of the optical fiber core wire; and a sheath that integrally covers the optical fiber core wire and the two protective materials. An optical fiber cable having a notch for taking out the optical fiber core in the longitudinal direction of the sheath,
The two protective materials are arranged such that one end of the two protective materials diagonally located across the optical fiber core wire is disposed near the end of the optical fiber core wire, and the width of the two protective materials is the optical fiber core. An optical fiber cable characterized by being wider than the line width.   2. The thin portion of the sheath serving as a tear start point of the tear notch is provided in the vicinity of one end of the protective material located near the end of the optical fiber core wire. Fiber optic cable.   The optical fiber cable according to claim 1 or 2, further comprising two strength members arranged in parallel with the optical fiber core wire interposed therebetween.   4. The optical fiber cable according to claim 3, wherein the two protective members are arranged in the vicinity of the strength member at the other end opposite to each other across the optical fiber core wire.

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