JP2000002811A - Structure of optical cable branching part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve workability of a connecting work of a prefabricated cable with a branching optical cable, a surplus length processing work of optical fibers, etc. SOLUTION: The structure of the optical cable branching part 10 comprises a connector fixing part 13 for fixing optical connectors 18, 18b for terminating a tip of optical fibers 16 led out of an optical cable 11 into a branching part protecting body 12 pre-arranged on the side of an optical cable 11 before laying so that the tip is connectable to optical fibers 20 on a branch cable 19 side, and a surplus length housing part 14 for curving and housing the surplus length of the optical fibers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an optical cable branching section for branching and connecting an optical cable to another branch optical cable.

[0002]

2. Description of the Related Art When laying an optical line inside a building or the like, a so-called prefabricated cable is frequently used. This prefabricated cable is an optical cable (or a so-called optical composite cable in which metal wires are composited) in which a branching section for branching and branching is provided in advance in each section or location where branching is planned. It is constructed by branch-connecting a branch cable to the branch part. In this prefabricated cable,
Since the drawing operation of the optical fiber (mainly the optical fiber core wire) and the metal wire is performed before the installation, only the connection operation needs to be performed after the installation at the branch portion, and the workability of the branch connection can be improved. For example, it is frequently used for laying a complicated optical line such as laying an optical line inside a building that requires connection between floors.

FIGS. 4A and 4B show a structure of a branch portion 1a of a conventional prefabricated cable 1. FIG. FIG.
As shown in (a), the branch portion 1a is formed in advance on the prefabricated cable 1 before laying, and is used to draw out an optical fiber 2 (mainly an optical fiber core) or a metal wire (not shown). The attachment of the optical connector 3 to the tip of the optical fiber 2, the attachment of the electrical connector to the tip of the metal wire, and the like are performed in advance. In general, the optical connector also serves as the optical connector 3 having the electric terminal. The branch portion 1a is installed at a target position by laying the prefabricated cable 1. After the prefabricated cable 1 is laid, an extra length 2a is secured in the optical fiber 2, an optical connector 3 at the tip of the optical fiber 2, an electrical connector for connecting a metal wire, and an optical connector adapter 4 to which the optical connector 3 is connected. To
Fix to fixed structures such as pillars of buildings. These operations are performed by workers on site. To the optical connector adapter 4, an optical connector 7 at the tip of an optical fiber 6 pulled out from the branch cable 5 pulled in is detachably connected, whereby the target optical fiber 2 on the prefabricated cable 1 side is connected.
The optical fiber 6 on the branch cable 5 side is optically connected.
Further, the metal wire drawn from the prefabricated cable 1 which is an optical composite cable is connected to the metal wire on the branch cable 5 side via an electrical connector at the tip thereof. When the connection between the optical fibers 2 and 6 and the connection between the metal wires are completed, as shown in FIG.
7 and the electrical connector are accommodated by a protective cover 8 covered from the outside. The protective cover 8 is fixed with a vinyl tape or the like.

[0004]

However, in the branching section 1a as described above, a worker brings in a large number of parts at the site where the optical cables 1 and 5 are connected to each other, so that the connector connection and the remaining space of the optical fiber 2 can be avoided. Work such as long processing, storage of the optical connector 3 and the optical connector adapter 4 by the protective cover 8, and fixing of the protective cover 8 must be performed. If the working space is narrow, it is difficult to improve workability. There was a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and can reduce the number of operations performed on site, and can efficiently perform operations such as processing excess length of an optical fiber even in a narrow work space. It is an object of the present invention to provide a structure of an optical cable branch that can be performed.

[0006]

The present invention has the following features to attain the object mentioned above. That is, the invention according to claim 1 has a structure of an optical cable branch portion provided at one or a plurality of positions in the longitudinal direction of the optical cable and for branching and connecting the optical cable to the branch optical cable, wherein the optical cable branch portion is provided in advance at the side of the optical cable before installation. In the provided branch part protection body, the optical fiber tip pulled out from the optical cable,
A connector fixing portion for fixing an optical connector that terminates to be connectable to the optical fiber on the side of the branch optical cable, and a fiber housing portion for storing the drawn optical fiber in a curved state. The structure of the optical cable branch section is a means for solving the above-mentioned problem. In the structure of the optical cable branch section, the optical fiber drawn out from the optical cable serving as the trunk is bent in advance in the fiber storage section, so it is not necessary to perform the bending processing again when connecting the connector to the optical fiber on the branch optical cable side. Work can be greatly reduced. In the bending process of the optical fiber at the connection site, the work space to be secured around is larger than other work, and if the extra length secured in the optical fiber is long, the bending process requires a larger working space. In the structure of the optical cable branch section, since the bending process is unnecessary, if the branch section formed in advance in the optical cable is drawn into the target branch work space, the optical fibers are connected to each other even if the work space is narrow. And other operations such as connector connection. In addition, since the optical connector is fixed at a fixed position in the connector fixing portion, the optical connector at the tip of the optical fiber on the branch optical cable side is simply connected to the optical connector fixed to the connector fixing portion. Both optical fibers on the branch optical cable side can be easily optically connected.

According to a second aspect of the present invention, in the structure of the optical cable branch portion according to the first aspect, the branch portion protection body is
A connector fixing portion for fixing the optical connector at the tip of the optical fiber drawn out of the optical cable to the resin of the branch portion protector, which is made of resin filled and solidified in the side portion of the optical cable, and the drawn out optical fiber And a fiber storage portion for embedding and fixing the embedded portion. According to the structure of the optical cable branch section, the branch section protection body can be formed extremely easily with resin, so that the construction time can be reduced and the cost can be reduced. In addition, since the optical connector and the optical fiber can be stably fixed by the branch portion protector, there is no fear that the optical cable may be displaced even when the optical cable is laid, and the laying workability can be further improved.

[0008] The invention described in claim 3 is claim 1 or 2.
In the structure of the optical cable branch section described above, the connector fixing section includes an electrical connector for electrically connecting metal wires to each other, and the metal drawn out of the optical cable into the branch section protection body through the electrical connector. The line is
It is characterized by being electrically connected to the metal wire on the branch optical cable side. The present invention is applied to a so-called optical composite cable containing an optical fiber and a metal wire. The electrical connector may be different from the optical connector.However, for example, it is also possible to incorporate a metal terminal into the optical connector so as to also function as an electrical connector. Thus, the number of connectors to be fixed can be reduced, so that the size and cost of the entire optical cable branch can be reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the structure of the optical cable branching portion of the present invention will be described with reference to FIGS. FIG. 1 is a front view showing the structure of the optical cable branching unit 10, and FIG. 2 is a front sectional view showing the internal structure of the optical cable branching unit 10. As shown in FIG. 1 and FIG. 2, the optical cable branch section 10 is an optical cable 11 (prefab cable).
A connector fixing portion 13 and a fiber housing portion 14 are provided inside a branch portion case 12 as a branch portion protector attached in the longitudinal direction of the connector, and further, the connector exposed on the side surface of the branch portion case 12. A detachable protective cover 15 that covers the fixing portion 13 from the outside is attached.

The optical cable 11 includes a plurality of optical fibers 1.
6 (mainly an optical fiber core) and a plurality of units 17 each housing a plurality of metal wires (not shown). Unit 17
From the outlet 11a formed by cutting the jacket, an optical fiber 16 to be branched is branched from the branch case 12
A plurality of optical connectors 18 which are drawn out into the optical fiber and terminate the ends of the optical fibers 16 so as to be connectable to the connectors are fixed to the connector fixing portions 13 respectively. The extra length 16a of the optical fiber 16 drawn into the branch part case 12 is stored in the fiber storage part 14, which is a space secured in the branch part case 12,
It is stored with a curvature radius (R30 or more) exceeding a specified value that does not affect optical characteristics. The cut portion of the unit 17 is subjected to a terminal treatment to prevent flooding or the like. Also,
It is also possible to pull out only a part of the plurality of optical fibers 16 housed in the unit 17 from the unit 17 and branch the optical fiber 16, and in this case, house the optical fiber 16 exposed at the outlet 11a in the reinforcing tube. Protect by doing. The optical fiber 16 drawn into the branch part case 12 does not necessarily need to secure the extra length 16a, and may be wired with a slight margin to the extent that no tension acts on the optical fiber 16 up to the connector fixing portion 13. In this case, the optical fiber 16 itself drawn from the outlet 11a is subjected to the bending process without any extra length.

An optical connector 21 at the tip of an optical fiber 20 on the side of the branch optical cable 19 is connected to the optical connector 18. Then, the optical fiber 16 on the optical cable 11 side,
The optical fiber 20 on the branch optical cable 19 side is optically connected. As the optical fiber 16, either a single core or a multiple core can be adopted. In addition, a metal wire is also drawn from the outlet 11a. The ends of these metal wires are connected to metal terminals built in or adjacent to the optical connector 18,
By connecting an optical connector 21 to which a metal wire on the branch optical cable 19 side is connected to the optical fiber 16, electrical continuity between the metal terminals of the optical connectors 18 and 21 is ensured, and not shown on the branch optical cable 19 side. It is electrically connected to the metal wire. The optical fibers 16 and 20 are
Either the one integrated with the metal wire or the one separate from the metal wire can be adopted. If the integrated one is used, if the optical fibers 16, 20 taken out from the optical cables 11, 19 are compared with each other, the two optical cables 11, 20 are used. The contrast between the metal wires is determined between 19, and the connection work becomes easy. The electrical connector is not limited to the one integrated with the optical connector 18 but may be another one.

Various configurations can be adopted as the optical connector 18. FIG. 2 shows a configuration in which an optical connector plug 18 a attached to the tip of a single-core optical fiber 16 is connected to an optical connector adapter 18 b fixed to the connector fixing portion 13. As the optical connector plug 18a and the optical connector adapter 18b applied to the single-core optical fiber 16, an SC type optical connector (Single fiber Coupling optical fibre) specified in JIS C 5973 is used.
ber connector). Optical connector plugs and optical connector adapters applied to multi-core optical fibers include, for example, M
The PO optical connector 18c (Multifiber Push On) is applied (see FIG. 1). An MPO-type optical connector 21a that terminates the multi-core optical fiber 20a on the branch optical cable 19 side so that the connector can be connected to the MPO-type optical connector 18c adopted as the multi-core optical connector. In the optical connector 18 including the optical connector plug 18a and the optical connector adapter 18b, since the optical connector plug 18a is connected to the optical connector adapter 18b fixed to the connector fixing portion 13, a cable is used. If the branching section 10 is disassembled, the connection of the optical fiber 16 to the optical connector adapter 18b can be switched. At the time of assembling the cable branch portion 10, the optical fiber 16 can be easily compared with the optical connector adapter 18b, and the assembling workability is improved.

The connection direction of the optical fiber 16 to the optical connector 18 (specifically, the connection direction of the optical connector plug 18a to the optical connector adapter 18b in this embodiment) is parallel to the longitudinal direction of the optical cable 11. In this case, the optical fiber 16 pulled out from the outlet 11a is substantially parallel to the optical cable 11 and
Since the wiring is carried out up to that point, the generation of the extra length 16a can be reduced, and the fiber housing portion 14 and the branch portion case 12 can be downsized. Further, since the curvature of the optical fiber 16 is small, there is an advantage that the optical characteristics of the optical fiber 16 can be easily maintained. If the branch case 12 is reduced in size, the work of pulling the optical cable branch 10 into a target installation becomes easier.
Further, the connection direction of the optical fiber 16 to the optical connector 18 may be perpendicular to the longitudinal direction of the optical cable 11.
However, in this case, a sufficient extra length 16a is required
6, it is necessary to increase the size of the fiber housing section 14 and the branch section case 12.

As the optical connector 18, in addition to the above-described configuration, for example, various optical connectors having a female housing, such as an optical connector receptacle, can be adopted. In this case, the optical connection between the optical fiber 16 on the optical cable 11 side and the optical fiber 20 on the branch optical cable 19 side can be performed without the intervention of the optical connector adapter 18b, and the number of components can be reduced. Further, a mechanical splice type optical fiber connector described in Japanese Patent Application No. 208478/1996 filed by the present applicant is also applicable. In this type of optical fiber connector, for example, the optical fiber 16 on the optical cable 11 side is inserted and fixed in advance in the optical fiber connector, and the optical fiber 20 on the branch optical cable 19 side is separately inserted into the optical fiber connector. , Optical fiber 1
6, 20 are butt-connected by an alignment mechanism in the optical fiber connector. In this type of optical fiber connector,
The split-structured element sandwiching the optical fibers 16, 20 to be butt-connected can be opened and closed by an opening member such as a wedge.
Switching connection between the two is possible. The branch optical cable 19
Needless to say, the number of cores of the optical fiber 20 on the side and the optical connector 21 at the tip of the optical fiber 20 are appropriately changed according to the configuration of the optical fiber 16 on the optical cable 11 side and the configuration of the optical connector 18.

The optical connector 18 comprising the optical connector plug 18a and the optical connector adapter 18b is connected by inserting the optical connector 21 at the tip of the optical fiber 20 on the branch optical cable 19 side into the optical connector adapter 18b. 16 and 20 can be easily connected to each other, and good connection workability can be obtained. The same applies to the multi-core optical connector such as the MPO optical connector 18c. As shown in FIG. 1, the optical connectors 18 are fixed to the connector fixing portion 13 in a plurality of arrangements, and when the protective cover 15 is opened, all of the optical connectors 18 are exposed. Optical fiber 20
By simply selecting the target optical connector 18 and connecting the optical connector 21, the optical connection to the optical fiber 16 on the optical cable 11 side can be easily performed, and the connection workability is improved.
In addition, since the optical connectors 18 and 21 are detachable, the switching connection can be easily performed.

In the structure of the optical cable branching section, the optical cable 11 is installed at a target place by laying the optical cable 11 by assembling the optical cable 11 beforehand at the target place. Then, the optical connector 21 at the end of the optical fiber 20 pulled out from the branch optical cable 19 for branching and branching separately is connected to the target optical connector 18 of the connector fixing part 13, and the optical cable 11 side, the branch optical cable 1
The optical cable 11 is branched and connected to the branch optical cable 19 by connecting the optical fibers 16 and 20 on the 9 side to each other.
At this time, the optical connector 18 of the connector fixing portion 13 is not displaced because it is fixed to the connector fixing portion 13, and the surplus length 16a in the fiber storage portion 14 does not change. There is no need for the extra-length processing related to No. 16. Therefore, there is no need to secure a work space for extra length processing around the optical cable branching section 10, and even in a narrow work space, the work of connecting the optical fibers 16, 20 can be performed efficiently. it can.

When the optical cable 11 is laid, the protective cover 15 is closed to cover the connector fixing portion 13, so that
The optical connectors 18 and 18c of the connector fixing portion 13 can be protected.
It can be performed by the same operation as the optical cable without the optical cable branching section 10. Optical fibers 16, 20
When the connectors are connected to each other, the protection cover 15 is opened (removed), and after the connection operation is completed, the protection cover 15 is closed again (attached) to protect the optical connectors 18 and 21. Therefore, in this optical cable branching section 10, the protection cover 15 is attached to the connector fixing section 13, instead of the work of attaching and fixing the protection cover to a fixed structure or the like, which is conventionally performed.
By simply attaching and detaching the connector, the connector fixing portion 13 can be protected and exposed very easily, and it is not necessary to separately secure a fixing structure for fixing the connector and a work space. Various configurations that can be easily attached and detached and opened and closed, such as a configuration that is opened and closed by rotating with a hinge or the like, can be adopted as the protective cover. As described above, according to the structure of the optical cable branch portion, the connection between the optical fibers 16 and 20 of the optical cables 11 and 19, the extra length processing, and the attachment / detachment of the protective cover 15 can be performed extremely easily. In addition, the number of components and tools to be brought to the connection site is extremely small, so that the workability can be improved and the connection work time can be reduced.

FIG. 3 shows the structure of an optical cable branch section according to a second embodiment of the present invention. In the drawings, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof will be simplified. The optical cable branching section 30 includes an optical fiber 1 in a branch protection body 31 formed of a resin provided to the side including the optical cable 11 near the outlet 11a.
6, the extra length 16a, and the optical connector 18 are embedded and fixed.

The branch part protection body 31 is integrally formed as a whole, and is provided by, for example, filling or curing a mold provided around the outlet 11a. The optical connector 18 is fixed in a semi-buried state to a connector fixing portion 31a which is one side portion of the branch portion protecting body 31, and a portion exposed from the connector fixing portion 31a has a light at the tip of the optical fiber 20 on the branch optical cable 19 side. The connector 21 is connectable. The plurality of optical connectors 18 are fixed to the connector fixing portion 31a in an array state. A detachable protective cover 15 is attached near the connector fixing portion 31a.
8 and the optical connector 2 connected to the optical connector 18
As in the first embodiment, the protection storage and exposure of 1 can be easily switched. Although not shown, in the structure of the optical cable branching section also, a multi-core optical fiber is pulled out from the unit 17 and the end of the multi-core optical fiber is connected to the connector fixing section 3.
Needless to say, it may be fixed to 1a.

The extra length 16a of the optical fiber 16 depends on the length of the fiber housing 3 between the connector fixing portion 31a and the outlet 11a.
Since it is embedded and fixed in 1b, the bending radius is stably maintained as long as the branch part protection body 31 is not deformed or broken. In addition, since the water blocking property is almost completely secured by the branch portion protection body 31, the optical characteristics of the optical fiber 15 and the electrical characteristics of the metal wire can be stably maintained for a long period of time. By embedding the branch portion protection body 31 in the resin, the oxidation resistance and chemical resistance of the metal wire can be obtained. The stability of the optical characteristics and the electrical characteristics obtained by the water stopping property and the like is the same for the optical cable 11.

According to the structure of the optical cable branch section, the branch section protection body 31 can be easily formed simply by filling the resin in a predetermined area defined by a mold or the like provided around the outlet 11a. Since the extra length 16a of the optical fiber 16, the optical connector 18 and the like can be fixed at a stroke, the assembling workability is greatly improved and the assembling can be performed in a short time. In addition, since the number of parts can be reduced, it is possible to further shorten the assembling time and reduce the cost by reducing the number of assembling work steps. The connection between the optical fibers 16 and 20 of the two optical cables 11 and 19, the extra length treatment, and the attachment / detachment of the protective cover 15 can all be performed extremely easily, and the number of components and tools brought to the connection site is extremely small. This is similar to the first embodiment in that the workability can be improved and the connection work time can be reduced.

Further, since the extra length 16a of the optical fiber 16 is embedded and fixed in the fiber housing portion 31b, for example,
The bending radius of the extra length 16a is prevented from fluctuating due to vibration or the like of the drawing operation of the optical cable 11 to the target laying position, and the optical characteristics can be stably maintained. When the branch part protection body 31 is formed from a plurality of divided bodies, a configuration in which the extra length 16a can be taken out can be adopted.

In the vicinity of the outlet 11a, the unit 17 is cut off when the optical fiber 16 is pulled out, and so on.
In some cases, the strength of the optical cable 11 near the outlet 11a is low.
Since the strength near 1a can be ensured, there is an advantage that inconveniences such as generation of twist due to the pulling force at the time of pulling and laying the optical cable 11 can be prevented, and the laying operation can be stably performed.

Incidentally, the structure of the optical cable branching portion of the present invention is not limited to the above embodiment, and it goes without saying that various modifications are possible. For example, the optical cable 11 can employ various configurations other than the optical composite cable, such as an optical cable that does not have a built-in composite metal wire. Further, in the embodiment, a plurality of units 17 are used as the optical cable 11.
However, the optical cable is not limited to this, and for example, has no unit,
A structure in which a number of optical fibers and metal wires are accommodated in one sheath can also be adopted. In this case, a so-called slot-type optical cable having a configuration in which a large number of optical fibers and metal wires are arranged and accommodated by slots accommodated in the cable can be adopted. Further, as an optical cable including the unit, a so-called air balloon type optical cable in which an optical fiber or a metal wire is fed by pressurized air or negative pressure into the unit can be adopted. Various configurations can also be adopted for the branch optical cable. The branch optical cable includes a single-core or multi-core optical cord and the like. Further, in the above embodiment, the shapes of the branch case and the molding resin employed as the branch protector are not limited to those shown in the drawings, and various shapes can be employed.

[0025]

As described above, according to the structure of the optical cable branch portion according to the first aspect, the optical fiber drawn from the optical cable is stored in the fiber storage portion in the branch portion protection body provided in advance in the optical cable. At the time of connection with the optical fiber on the branch optical cable side, the optical fiber on the branch optical cable side is only connected to the optical fiber on the connector side, and the optical fiber in the fiber storage section is not pulled out. This eliminates the need for the bending process, so that work such as connector connection between optical fibers can be performed even in a narrow work space. In addition, since the optical connector is fixed at a fixed position in the connector fixing portion, the optical connector at the tip of the optical fiber on the branch optical cable side is simply connected to the optical connector fixed to the connector fixing portion. It is possible to easily optically connect both optical fibers on the branch optical cable side, and to achieve an excellent effect that connection workability is improved.

According to the structure of the optical cable branch part according to the second aspect, the branch part protection body is made of resin which is filled and solidified on the side of the optical cable, and the resin of the branch part protection body is attached to the optical cable. Since the connector includes a connector fixing portion for fixing the optical connector at the tip of the optical fiber drawn out of the connector and a fiber housing portion for burying and fixing the drawn out optical fiber, it is possible to extremely easily form the branch portion protective body with resin. As a result, the optical connector and the optical fiber can be stably fixed, resulting in excellent effects such as lower cost and easier improvement of the work of laying the optical cable.

According to a third aspect of the present invention, the connector fixing portion of the branch portion case includes:
Equipped with an electrical connector for electrically connecting metal wires,
Through this electrical connector, the metal wire built into the cable main body is electrically connected to the metal wire on the branch optical cable side. Similarly, the connector connection provides an excellent effect that the connection operation can be performed in a short time.

[Brief description of the drawings]

FIG. 1 is a front view showing a first embodiment of the structure of an optical cable branch section of the present invention.

FIG. 2 is a front sectional view showing the structure of the optical cable branch part of FIG.

FIG. 3 is a front sectional view showing the first embodiment of the structure of the optical cable branch section of the present invention.

4A and 4B are diagrams showing a structure of a conventional optical cable branching unit, wherein FIG. 4A is a front view showing a state where the optical cable branching unit is drawn into a target position and installed, and FIG. It is a front view which shows a branch connection state.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Optical cable branch part, 11 ... Optical cable (optical composite cable, prefabricated cable), 12 ... Branch part protection body (branch case), 13 ... Connector fixing part, 14 ... Fiber storage part, 16 ... Optical fiber, 16a ... Light Fiber (extra length), 18: Optical connector, 18a: Multi-core optical connector (M
PO type optical connector), 19 ... branch optical cable, 20 ... optical fiber, 30 ... optical cable branch part, 31 ... branch part protection body (resin), 31a ... connector fixing part, 31b ... fiber storage part.

Claims (3)

[Claims] 1. An optical cable branching portion provided at one or a plurality of locations in a longitudinal direction of an optical cable (11), for branching and connecting the optical cable to a branching optical cable (19), wherein the optical cable branch portion is provided on a side of the optical cable before laying. An optical connector in which a distal end of an optical fiber (16) drawn out of the optical cable is connected to an optical fiber (20) on the branch optical cable side so as to be connectable to an optical fiber (20) on the branch optical cable in a branch unit protector (12, 31) provided in advance. An optical cable branching section comprising: a connector fixing section (13, 31a) for fixing (18, 18c); and a fiber storage section (14, 31b) for storing the drawn optical fiber in a curved state. Structure (10,
30). 2. The branch part protector (31) is made of a resin that is filled and solidified on the side of the optical cable, and the resin of the branch part protector is provided with light at the tip of the optical fiber drawn out of the optical cable. The structure of an optical cable branch section according to claim 1, further comprising a connector fixing section (31a) for fixing a connector, and a fiber storage section (31b) for burying and fixing the drawn optical fiber. 3. The connector fixing portion includes an electrical connector for electrically connecting metal wires to each other, and the metal wire drawn out of the optical cable into the branch portion protection body through the electrical connector is provided. 3. The structure of the optical cable branch section according to claim 1, wherein the optical cable branch section is electrically connected to a metal wire on the branch optical cable side.