JP2004252070A - Structure for connecting metal tube-type fiber optic cable with longitudinally added tensile strength fiber and optical connector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connection structure that allows an optical connector to easily and reliably be fitted to a metal tube-type fiber optic cable to which tensile strength fiber is longitudinally added. <P>SOLUTION: The tensile strength fiber 4 of the metal tube-type fiber optic cable 1 is exposed longer than a metal tube 3 by peeling the coating 5 of a terminal part. The exposed metal tube 3 is sheathed with sleeves 6 and 7 with the tensile strength fiber 4 put therein, the tensile strength fiber 4 is folded back to the outside of the sleeve 7 after caulking the sleeve 7 and inserted into the inside of the sleeve 6, and the sleeve 6 is caulked and fixed to the outer circumference of the metal tube 3. The terminal part of the metal tube-type fiber optic cable which is thus processed is fitted into a groove formed on a boot of the optical connector by locking the sleeve 6 in a fall-preventive state. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connection structure for attaching an optical connector to a metal tube type optical fiber cable having tensile strength fibers longitudinally attached.
[0002]
[Prior art]
When connecting a metal tube type optical fiber cable to a device with a connector, the metal tube that covers and protects the outer periphery of the optical fiber core wire is securely connected to the optical connector, and a strong pulling force is applied to the optical fiber core wire. In this state, it is required to provide a degree of freedom (flexibility) to the connection portion with the connector to facilitate connection to the device.
[0003]
As a prior art of a connection structure for this purpose, for example, there is one disclosed in Patent Document 1 below.
[0004]
[Patent Document 1]
JP-A-6-118272
In the connection structure disclosed in Patent Document 1, a plurality of holes are provided in the vicinity of the distal end of a metal tube for protecting a core wire, and further inserted into the optical connector or a connection component with the optical connector between the optical fiber core wire and the metal tube. An elastic piece having a cylindrical portion and an engaging claw is provided, and the engaging claw of the elastic piece is locked in the hole provided in the metal tube so that the metal tube is connected to the optical connector or a connection part with the optical connector. ing.
[0006]
In addition, the protective member at the cable end is replaced with a flexible tube (flexible tube), one end of the flexible tube is fixed to the cable jacket, and the optical connector is fixed to the other end with screws. Fiber processed products are commercially available.
[0007]
[Problems to be solved by the invention]
The outer diameter of the metal tube of the metal tube type optical fiber cable is generally very small, about several mm. In the connection structure of Patent Document 1, it is necessary to make a hole for engaging the engaging claw in the thin metal tube, and it becomes difficult to process the hole. In particular, since this hole requires dimensional accuracy and positional accuracy, it is difficult to machine the hole.
[0008]
In addition, since the terminal processing is performed in a state where the optical fiber core is stored in the metal tube, there is a possibility that the internal optical fiber core may be damaged or broken at the time of drilling.
[0009]
If the dimensional accuracy and positional accuracy of the hole provided in the metal tube become rough, the retaining of the optical connector becomes insufficient, and the effect of protecting the optical fiber core is reduced.
[0010]
In addition, the connection structure of Patent Literature 1 has a complicated shape of a connection component, which is disadvantageous in terms of manufacturing cost.
[0011]
In the case of using a flexible tube, since the flexible tube is fixed to the optical connector with small-sized screws, workability at the time of screw tightening is poor.
[0012]
An object of the present invention is to provide a connection structure for an optical connector that eliminates these problems.
[0013]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, in the present invention, a metal tube is arranged around the outer periphery of a single-core or multi-core optical fiber core, a tensile fiber is vertically attached to the outer periphery of the metal tube, and further coated on the outside. The metal tube type optical fiber cable having the structure in which the metal tube is exposed is processed by removing the coating of the terminal portion so that the tensile strength fiber is exposed longer than the metal tube. Then, a first sleeve and a second sleeve disposed closer to the distal end of the metal tube than the first sleeve are fitted through the tensile strength fiber inside, and the tensile strength fiber passing through the inside of the second sleeve is fitted to the outside of the second sleeve. And inserted into the inside of the first sleeve, and caulked the first and second sleeves and fixed to the outer periphery of the metal tube, or the first and second sleeves and the tensile strength fiber were bonded and fixed to the metal tube with an adhesive, Above Of the metal tube type optical fiber cable, which has been subjected to the above, is fitted into the groove provided in the boot of the optical connector by locking the first sleeve in a retaining state. Provided is a connection structure between a fiber cable and an optical connector. When caulking and fixing the second sleeve with this structure, it is preferable to caulk the second sleeve before folding back the tensile strength fiber.
[0014]
Further, the first sleeve is inserted through the inside of the tensile strength fiber into the metal pipe exposed to the end portion of the cable by performing the same terminal treatment as described above, and the tensile strength fiber passing through the inside of the first sleeve is passed through the first sleeve. After being folded back to the outside of the one sleeve, the second sleeve is laid over the outer periphery of the first sleeve, and the tensile strength fiber obtained by folding the second sleeve and the first sleeve is sandwiched therebetween and simultaneously caulked and fixed to the outer periphery of the metal tube. Then, the terminal portion of the metal tube type optical fiber cable which has been subjected to the above processing is fitted into the groove provided in the boot of the optical connector by locking at least one of the first and second sleeves in a retaining state. The present invention also provides a connection structure between an optical connector and a metal tube type optical fiber cable longitudinally attached with a tensile fiber.
[0015]
[Action]
The connection structure of the present invention is the same as a general terminal treatment of an optical fiber cable, that is, stripping the coating, exposing the exposed tensile fiber and cutting off the excess length of the metal tube, and then using the sleeve to remove the tensile fiber. Since the sleeve is held down by crimping or bonding to the sleeve, there is no need to make a hole for locking in the metal tube, and there is no need for screws or tools that require a power supply, and the workability of optical connector connection is improved.
[0016]
Further, since the component used for retaining the tensile strength fiber is a sleeve having a simple structure, the production of the component is simple and the component price can be reduced.
[0017]
Furthermore, since the tensile strength fiber is retained using the two sleeves in a folded state, the fixing force of the tensile strength fiber is increased, and the tensile strength of the connection portion is increased.
[0018]
In addition, when the first and second sleeves are overlapped and caulked at the same time, the caulking operation may be performed once, and the workability is further improved.
[0019]
Since the sleeve is retained by the boot of the optical connector, the flexibility of the distal end side of the optical connector is secured, and the connection to the device can be performed without any trouble.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows an embodiment of the connection structure of the present invention. In the figure, reference numeral 1 denotes a metal tube type optical fiber cable, and reference numeral 20 denotes an optical connector having a boot 21 attached to a rear portion.
[0021]
As shown in FIG. 2, the metal tube type optical fiber cable 1 protects the outer circumference of a single-core or multi-core optical fiber core wire 2 by covering it with a metal tube 3. A tensile strength fiber 4 for increasing the tensile strength is provided in a longitudinally attached manner, and the outside thereof is further covered with a coating 5.
[0022]
A required length of the coating 5 at the end of the metal tube type optical fiber cable 1 is stripped off, and the exposed metal tube 3 and the extra length of the tensile strength fiber 4 are cut off to expose the optical fiber core 2 to the required length. Let it. At this time, the exposed portion of the tensile strength fiber 4 is left longer than the exposed portion of the metal tube 3.
[0023]
After performing the above processing, the tensile strength fiber 4 is stopped using two metal sleeves. This operation is performed according to the procedures shown in FIGS.
[0024]
In the terminal treatment of FIG. 3, the sleeve 6 having the locking piece 6a (the collar in the figure is a flange) and the simple cylindrical sleeve 7 are formed by passing the tensile strength fiber 4 peeled out inside the sleeve into the metal tube 3. First, the sleeve 7 is caulked and fixed to the outer periphery of the metal tube 3, and the tensile strength fiber 4 is sandwiched between the sleeve 7 and the metal tube 3. Next, the tip side of the tensile strength fiber 4 is folded back along the outer surface of the sleeve 7 and inserted into the inside of the sleeve 6 with the locking piece, and then the sleeve 6 is caulked and fixed to the outer periphery of the metal tube 3. After the tensile strength fiber 4 is fixed at the two locations, the end of the metal tube type optical fiber cable 1 is fitted into the groove 22 (see FIG. 1) provided in the boot 21 of the optical connector, and the locking piece 6a is engaged with the boot 21. Then, the terminal is stopped from the connector 20. The end of the optical fiber 2 is attached to the housing of the connector 20 with the ferrule 23 attached.
[0025]
In the terminal treatment in FIG. 4, the sleeves 6, 7 having the same shape as in FIG. 3 are used, and the sleeves 6, 7 are fixed with an adhesive without caulking. That is, after the sleeve 6 is fitted to the outside of the stripped metal tube 3, the adhesive 8 is applied to the portion a in the figure, then the sleeve 7 is fitted, and the tip side of the tensile strength fiber 4 is moved along the outer surface of the sleeve 7. Fold it back and insert it inside the sleeve 6 with the locking piece. Thereafter, the adhesive 8 is applied again to the portion b in the figure, and the sleeves 6 and 7 and the tensile strength fiber 4 are bonded and fixed to the metal tube 3. Also in this structure, the tensile strength fibers 4 are fixed at a plurality of locations, and the tensile strength fibers 4 are securely retained, thereby increasing the tensile strength of the connection portion. The terminal unit that has performed the processing of FIG. 4 is also connected to the optical connector 20 in the same manner as the terminal unit of FIG. The sleeves 6 and 7 used for the terminal portion in FIG. 3 are metal sleeves that can be caulked. However, the sleeves 6 and 7 used for the terminal portion in FIG. Not limited.
[0026]
5 is a modified sleeve 9 having a large-diameter portion 9a fitted to the end of the cable jacket 5 and a small-diameter portion 9b fitted to the outer periphery of the exposed metal tube 3, and a larger diameter than the sleeve 9 and a rear portion. The tensile strength fiber 4 is retained using a sleeve 10 having a locking piece 10a protruding both inside and outside.
[0027]
The deformed sleeve 9 is fitted to the position where it abuts the cable jacket 5, and the tensile strength fiber 4 that has passed through the inside of the deformed sleeve 9 is folded back along the outer periphery of the sleeve 9. Thereafter, the sleeve 10 is fitted to the outside of the small diameter portion 9b, and the sleeve 10 and the small diameter portion 9b of the sleeve 9 are simultaneously caulked from the outside. In this terminal processing section, the two sleeves 9 and 10 are fixed only by performing caulking once, and the tensile strength fiber 4 is also provided between the small-diameter portion 9b of the sleeve 9 and the metal tube 3 and between the small-diameter portion 9b and the sleeve. 10 and is fixed at two places, so that the workability and the fixing force of the tensile strength fiber 4 are improved.
[0028]
In the metal tube type optical fiber cable 1 subjected to the processing of FIG. 5, the processed terminal portion is fitted into the groove 22 (see FIG. 1) provided in the boot 21 of the optical connector 20, and the locking piece 10a is connected to the boot 21 to prevent the connector from being pulled out. In the case of this structure, the locking piece 10a may be provided on the sleeve 9, and the locking piece may be provided on both the sleeves 9 and 10.
[0029]
【The invention's effect】
As described above, in the connection structure of the present invention, the tensile strength fiber vertically attached to the outer circumference of the metal pipe is fixed to the outer circumference of the metal pipe peeled off at the end portion of the cable using two sleeves, The optical connector is attached to the cable end by locking the sleeve used for fixing the tensile strength fiber to the boot of the optical connector.Therefore, a hole for engaging the metal tube is made, and the protective material at the end is replaced with a flexible tube. There is no need to screw the optical connector to the flexible tube, thereby facilitating the mounting of the optical connector, improving the fixing force of the tensile strength fiber, and thereby improving the reliability of the connection portion.
[0030]
In addition, the sleeve does not require complicated processing, can be manufactured at low cost, and connection cost can be reduced.
[0031]
In the case where two sleeves are overlapped and caulked at the same time, the caulking operation may be performed once, and the workability is further improved.
[Brief description of the drawings]
FIG. 1 is a partially broken plan view showing an embodiment of a connection structure according to the present invention; FIG. 2 is a perspective view of a metal tube type optical fiber cable to which tensile strength fibers are longitudinally added; FIG. FIG. 4 is a diagram showing a second embodiment of terminal processing of a metal tube type optical fiber cable. FIG. 5 is a diagram showing a third embodiment of terminal processing of a metal tube type optical fiber cable. Description】
DESCRIPTION OF SYMBOLS 1 Metal tube type optical fiber cable 2 Optical fiber core wire 3 Metal tube 4 Tensile fiber 5 Coating 6, 7 Sleeve 6a Lock piece 8 Adhesive 9 Deformed sleeve 9a Large diameter section 9b Small diameter section 10 Sleeve 10a Lock piece 20 Optical connector 21 Boots 22 Groove 23 Ferrule

Claims (2)

A metal tube type optical fiber cable having a structure in which a metal tube is arranged around the outer periphery of a single-core or multi-core optical fiber core, tensile strength fibers are vertically attached to the outer periphery of the metal tube, and a coating is further arranged on the outside thereof. The terminal portion is peeled off and treated so that the tensile strength fiber is exposed longer than the metal tube. The metal tube exposed at the terminal portion of the metal tube type optical fiber cable is provided with a first sleeve and a metal which is more metal than the first sleeve. A second sleeve disposed on the distal end side of the tube is inserted through the tensile strength fiber inside, and the tensile strength fiber that has passed through the inside of the second sleeve is folded back to the outside of the second sleeve and inserted inside the first sleeve. 1, the second sleeve is caulked and fixed to the outer periphery of the metal tube, or the first and second sleeves and the tensile strength fiber are bonded and fixed to the metal tube with an adhesive, and the metal tube type optical fiber cable which has been subjected to the above-described processing is used. Terminal And to fit with the first sleeve is engaged in the retaining state in a groove provided in the optical connector boots, vertical served with tensile strength fibers metal tube type optical fiber cable and connection structure of the optical connector. A metal tube type optical fiber cable having a structure in which a metal tube is arranged around the outer periphery of a single-core or multi-core optical fiber core, tensile strength fibers are vertically attached to the outer periphery of the metal tube, and a coating is further arranged on the outside thereof. The end portion is peeled off and treated so that the tensile strength fiber is exposed longer than the metal tube, and the first sleeve is passed through the metal tube exposed at the end portion of the metal tube type optical fiber cable so that the tensile strength fiber passes through the inside. After fitting, the tensile strength fiber passing through the inside of the first sleeve is folded back to the outside of the first sleeve, then the second sleeve is overlapped on the outer periphery of the first sleeve, and the tensile strength fiber is formed by folding the second sleeve and the first sleeve. The end portion of the metal tube type optical fiber cable, which has been processed as described above, is fixed to the outer circumference of the metal tube at the same time, and the first and second three ends are inserted into the grooves provided in the boot of the optical connector. Vertical served metal tube type optical fiber connection structure of the cable and the optical connector at least either one has to fit in to engage with the retaining state, the tensile strength fibers.

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