JP4094980B2 - Fiber optic cable - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical fiber tape in which a core wire containing groove extending along the length direction is formed on the outer periphery and a plurality of optical fiber core wires are integrally formed and housed in the core wire containing groove of the spacer A connector is attached to the cable end of the cable body including the optical fiber, and the optical fiber ribbon is branched in the connector, and each of the optical fibers is independent from the connector. It is related with the optical fiber cable pulled out.
[0002]
[Prior art]
Until now, in CATV (community antenna television system), coaxial cables have been mainly used as transmission cables for all trunk lines, branch lines, distribution lines, service lines, and indoor lines. Such a coaxial cable is attached to a connector receiver of an attachment side device via a C14 type connector of EIJA RC-5222A (Japan Electronic Machinery Manufacturers Standard) attached to the end of the cable, and branching or the like is caused inside the attachment side device Made.
[0003]
However, in recent years, as the number of broadcasting channels has been increasing, and higher quality and diverse video services are required, optical fiber cables are used for trunk lines and branch lines instead of coaxial cables. It is becoming.
[0004]
For example, in Patent Document 1, a cable fixing bracket that is fixed by sandwiching a tension member of an optical fiber cable is fitted inside a fixed adapter that is screw-tightly connected to a housing of an optical transmission device. The structure is fixed and held, and only the core of the optical fiber cable is pulled into the housing of the optical transmission device through the core hole formed in the cable fixing bracket. Further, the gasket is installed in the portion where the optical fiber cable is introduced into the fixed adapter. It is disclosed that the structure is airtight. And according to this, in order to draw the optical fiber cable into the optical transmission device arranged in the signal transmission path such as CATV, it is not necessary to provide the cable fixing bracket inside the optical transmission device, and the optical fiber cable is securely connected. It can be fixed and airtight and drawn in.
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-54912
[Problems to be solved by the invention]
By the way, in the optical fiber cable, a spacer is provided in the cable body, and an optical fiber tape core wire composed of a plurality of optical fiber core wires is accommodated in a core wire accommodation groove formed in the spacer, and In some cases, a connector is attached to a cable end of a cable body, and an optical fiber ribbon is branched in the connector, and each of a plurality of optical fibers is pulled out independently from the connector.
[0007]
In such an optical fiber cable, an optical fiber tape core is branched into a plurality of optical fiber cores in a connector having a small space. However, if an optical fiber tape core is branched into optical fiber cores in a spacer. There is a risk that the optical fiber core wire is broken at the corner of the spacer and broken.
[0008]
The present invention has been made in view of such points, and the object of the present invention is a structure in which an optical fiber ribbon is branched into a plurality of optical fibers in a connector. An object of the present invention is to provide an optical fiber cable in which breakage is suppressed.
[0009]
[Means for Solving the Problems]
The present invention includes a spacer in which a core wire receiving groove is formed so as to extend along the length direction, an optical fiber tape core wire made of a plurality of optical fiber core wires and housed in the core wire receiving groove of the spacer, A connector is attached to the cable end of the cable body having the optical fiber tape, the optical fiber ribbon is branched in the connector, and each of the optical fibers is independent from the connector. An optical fiber cable drawn out
In the cable end portion of the cable body, the optical fiber tape core wire branches out to the plurality of optical fiber core wires after being drawn out so as to protrude from the end of the spacer,
The connector has second and third members that are each formed in a cylindrical shape, and the cable main body is inserted through the screw structure to be coupled,
The cable main body is covered with tape so as to form a tapered shape having a larger diameter toward the distal end side, corresponding to the components of the screwed structure of the second and third members of the connector. An annular gasket and a metal ring are provided in an outer fit,
By screwing structure of the second and third members, characterized in that the annular gasket and the metal ring constitutes a pinched seal structure between said second and third members.
[0010]
According to the above configuration, although the optical fiber tape core wire is branched into a plurality of optical fiber core wires in the connector, a plurality of optical fiber tape core wires are drawn out so as to protrude from the end of the spacer. Since the optical fiber is branched into the optical fiber, the optical fiber is not broken at the corner of the spacer to be broken, and the breakage of the optical fiber is suppressed.
[0011]
The protruding length of the optical fiber ribbon from the end of the spacer is not particularly limited, but if it is 1 mm or more, contact with the corner of the end of the spacer of the optical fiber can reliably be avoided. .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0013]
FIG. 1 shows an optical fiber cable C according to an embodiment of the present invention. The optical fiber cable C constitutes a branch line drawn from the closure.
[0014]
The optical fiber cable C has a configuration in which a C14 connector 50 of EIJA RC-5222A (Japan Electronic Machinery Manufacturers Association standard) is attached to the cable end of the cable body 10.
[0015]
FIG. 2 shows a cross section of the cable body 10.
[0016]
The cable body 10 has a tension member 11 made of a steel wire provided at the center of the cable covered with a resin spacer 12, and the outside thereof is covered with a presser winding 13 made of a nonwoven fabric. The structure is covered with a sheath 14. The wrap sheath 14 is obtained by attaching an aluminum tape 14b to the inner peripheral surface of a sheath body 14a made of a flexible resin. A tear string 15 is provided along the length direction between the presser winding 13 and the wrap sheath 14, and the wrap sheath 14 is peeled by a predetermined length by pulling the lace sheath 14 and longitudinally tearing the wrap sheath 14. Can be done. On the outer peripheral surface of the spacer 12, a pair of U-shaped core wire receiving grooves 12a are formed so as to sandwich the tension member 11 in the cross section so as to form a double helix along the length direction. The four optical fiber tape core wires 20 are accommodated in one of the core wire accommodation grooves 12a. As shown in FIG. 3, the optical fiber ribbon 20 is formed by coating four optical fiber cores 30 arranged in parallel with a coating layer 21 made of an ultraviolet curable resin or the like. Each optical fiber core 30 is obtained by coating an optical fiber 31 made of a quartz or resin core 31a and a clad 31b with a coating layer 32 made of an ultraviolet curable resin or the like.
[0017]
FIG. 4 shows a longitudinal section of the cable end of the cable body 10.
[0018]
At the cable end of the cable body 10, as shown in FIG. 5, the wrap sheath 14 is peeled off by a predetermined length by the tear string 15 so that the spacer 12 protrudes, and the optical fiber ribbon 20 is After being pulled out from the end of the spacer 12 by 1 mm or more, it is branched into four optical fiber cores 30. The optical fiber ribbon 20 is branched into four optical fibers 30, each extending as a single-core cord 40 that is independent of each other. Further, the tension member 11 protrudes and extends from the end of the spacer 12 to about half the length of the single-core cord 40. As shown in FIG. 6, each single-core cord 40 is coated with a fiber coating layer 41 made of a tubular woven fabric made of high-strength fibers such as aramid fibers, and an optical fiber core wire 30 provided at the center of the cord. The outside is covered with a resin sheath 42 made of a flexible resin such as vinyl chloride resin. A single-core connector 43 is attached to the end of each single-core cord 40.
[0019]
A cylindrical sleeve is provided at the cable end of the cable body 10 so as to accommodate the end point of the wrap sheath 14 and the start point of the single core cord 40, that is, the branching portion of the optical fiber ribbon 20 to the optical fiber 30. 16 is covered. A sealing tape 17 is wound around the end point of the wrap sheath 14 so as to have an outer diameter substantially equal to the inner diameter of the sleeve 16, and about half of that portion is fitted into the sleeve 16. As shown in FIG. 7, the sleeve 16 is provided with four screw holes 16 a at equal intervals in the circumferential direction corresponding to the wound portion of the sealing tape 17 fitted in the sleeve 16. A screw 16b is screwed into the hole 16a, and the cable main body 10 is locked by a screw tip via a sealing tape 17, thereby preventing the cable main body 10 from coming off from the sleeve 16. Further, a rubber tape 18 such as a butyl rubber tape is wound around the end portion of the sleeve 16 and a portion of the sealing tape 17 that is not fitted into the sleeve 16 so as to form a tapered shape. Further, a resin tape 19 such as a vinyl chloride tape is wound around the sleeve 16 and the rubber tape 18. The sleeve 16 is filled with an elastic resin made of an elastic epoxy resin or the like. As described above, the branch portion in which the optical fiber tape core wire 20 is branched into the optical fiber core wire 30 to form the single core cord 40 is accommodated in the sleeve 16, and the portion is hardened with an elastic resin. Thus, exposure and deformation of the low-strength optical fiber core wire 30 are prevented.
[0020]
This C14 type connector 50 has a configuration in which the first to third members 51, 52, 53 are sequentially coupled in the length direction, and has a regular hexagonal cross section as a whole and a cylindrical shape having a cylindrical hole. belongs to. The first member 51 is configured to be short, and male screws are formed on the outer sides of both ends. The second member 52 is configured to be long, and an internal thread is formed inside one end of the first member 51 to be engaged with one external thread, and an external thread is formed outside the other end. The third member 53 has a female screw that is screwed into the male screw of the second member 52 inside one end, and a cable insertion hole 53 a that is substantially equal to the outer shape of the cable body 10 at the other end. Synthetic rubber O-rings 54 are externally fitted to the base end sides of the male threads of the first and second members 51 and 52 so that a sealing effect can be obtained when a threaded structure is formed. It has become.
[0021]
When the C14 connector 50 is attached to the cable body 10, first, the third member 53, the synthetic rubber annular gasket 55 and the metal ring 56 are inserted into the cable body 10 before fixing the sleeve 16 and the like. To do.
[0022]
Next, after fixing the sleeve 16 or the like to the cable body 10, the second member 52 is provided so as to cover the sleeve 16, and the male screw of the third member 53 is screwed into the second member 52. At this time, the gasket 55 and the metal ring 56 are sandwiched between the end of the second member 52 and the third member 53, whereby a sealing action is obtained.
[0023]
Next, one male screw of the first member 51 is screwed into the female screw of the second member 52.
[0024]
Then, the attachment of the optical fiber cable C to the attachment-side device 60 is performed by screwing the other male screw of the first member 51 into the female screw formed in the connector receiver 61 as shown in FIG. The ratio of the screwing torque between the first member 51 and the connector receiver 61, the screwing torque between the first member 51 and the second member 52, and the screwing torque between the second member 52 and the third member 53 is as follows. , Preferably 10 to 5 to 1.
[0025]
According to the optical fiber cable C having the above configuration, although the optical fiber ribbon 20 is branched into a plurality of optical fibers 30 in the C14 connector 14, the optical fiber ribbon 20 is the spacer 16. Since the optical fiber core wire 30 is branched to the plurality of optical fiber core wires 30 after being drawn out from the end, the optical fiber core wire 30 is not broken and broken at the end corner of the spacer 16, and the optical fiber core The breakage of the wire 30 will be suppressed.
[0026]
In the above embodiment, the optical fiber cable C constituting the branch line is used. However, the present invention is not particularly limited to this, and a trunk line, a distribution line, a lead-in line, and an indoor wiring may be formed.
[0027]
Moreover, in the said embodiment, although it shall have one 4 optical fiber tape core wire 20, it is not limited to this in particular, A multi-fiber optical fiber tape core wire may be sufficient, It may have a plurality of optical fiber ribbons.
[0028]
【The invention's effect】
As described above, according to the present invention, the optical fiber core wire is not broken and damaged at the corners of the spacer, and the optical fiber core wire is prevented from being damaged.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an optical fiber cable according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the cable body.
FIG. 3 is a cross-sectional view of the optical fiber ribbon.
FIG. 4 is a longitudinal sectional view of a cable end portion of a cable body.
FIG. 5 is a side view of the main part of the cable end of the cable body.
FIG. 6 is a cross-sectional view of a single core cord.
FIG. 7 is an explanatory diagram of the locking of the cable body by a sleeve.
FIG. 8 is an explanatory view showing an optical fiber cable mounting structure.
[Explanation of symbols]
C optical fiber cable 10 cable body 11 tension member 12 spacer 12a core wire receiving groove 13 holding winding 14 lap sheath 14a sheath body 14b aluminum tape 15 tear string 16 sleeve 16a screw hole 16b screw 17 sealing tape 18 rubber tape 19 resin tape 20 optical fiber Tape core wire 21 Cover layer 30 Optical fiber core wire 31 Optical fiber strand 31a Core 31b Clad 32 Cover layer 40 Single core cord 41 Fiber cover layer 42 Resin sheath 43 Single-core connector 50 C14 connector 51 First member 52 Second Member 53 Third member 53a Cable insertion hole 54 O-ring 55 Gasket 56 Metal ring 60 Mounting side device 61 Connector receiver

Claims (2)

A cable comprising a spacer in which a core wire receiving groove is formed so as to extend along the length direction, and an optical fiber tape core wire made of a plurality of optical fiber core wires and housed in the core wire receiving groove of the spacer A connector is attached to the cable end of the main body, the optical fiber ribbon is branched in the connector, and each of the plurality of optical fibers is pulled out of the connector independently of each other. Optical fiber cable,
In the cable end portion of the cable body, the optical fiber tape core wire branches out to the plurality of optical fiber core wires after being drawn out so as to protrude from the end of the spacer,
The connector has second and third members that are each formed in a cylindrical shape, and the cable main body is inserted through the screw structure to be coupled,
The cable main body is covered with tape so as to form a tapered shape having a larger diameter toward the distal end side, corresponding to the components of the screwed structure of the second and third members of the connector. An annular gasket and a metal ring are provided in an outer fit,
By screwing structure of the second and third members, the optical fiber, characterized in that the annular gasket and the metal ring constitutes a pinched seal structure between said second and third members cable. The optical fiber cable according to claim 1,
The optical fiber cable, wherein the optical fiber ribbon is drawn out so as to protrude 1 mm or more from the end of the spacer and then branched into the plurality of optical fibers.

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