JP2001215340A - Connecting part and connecting member for optical cable having a small number of core wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a connecting member for an optical cable capable of miniaturizing and lightening a connecting part without using a conventional connecting box as a connecting point for the optical cable having a small num ber of core wires. SOLUTION: The connecting member 1 is made of an aluminum alloy or the like as shown by figures (A), (B), a supporting wire storing part 2 and a coated optical fiber storing part 3 are formed as recessed grooves in the longitudinal direction. In order to connect a self supporting type optical cable as shown by figure (C), a sheath is removed, taken-out coated optical fibers are fusion spliced, the connected part is stored in the coated optical fiber storing part, the coated optical fibers are set to be nearly linear while slightly pulling them to both sides so as to naturally extend the main body sides of both side cables, a supporting wire fixing screw 4 is turned, and the supporting wire is fixed to the connecting member. Thereafter, a heat shrinkable tube is heat shrunk, and a protective sheathing is composed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connecting portion and a connecting member of a small-fiber-number optical cable suitable for use in dropping an optical fiber to a subscriber's house.

[0002]

2. Description of the Related Art Conventionally, for connection of an optical cable outdoors, a connection box called a closure is fixed to an imaginary support line or a building, and an optical cable to be connected is introduced therein.
After fixing the optical cable to be connected to this connection box inside the connection box, take out multiple optical fibers to be connected with sufficient length, connect them, and then loosen the optical fiber. Was wound up and stored in the extra length storage part in the connection box. Until now, even a small number of optical cables, such as one or two cores, was connected using a connection box having such a structure, so the connection part was much larger than the optical cable. Placing a connection point at an intermediate point, such as between telephone poles or between a telephone pole and a house, causes a load on the optical cable such as wind pressure or snowfall.Therefore, it is difficult to provide a connection point without a supporting structure. there were.

[0003] In addition, when the connecting box is supported on a supporting line or a structure such as a building, there is also a problem of aesthetic appearance. On the other hand, conventionally, since the optical distribution network is limited to the trunk line, there is almost no need to connect a small number of optical cables. For this reason, it is difficult to make a connection in the middle, and if the cable length becomes insufficient in the installation route, prepare an optical cable having a small number of fibers having a sufficient length in advance and cut off the excess. When changing the route of an existing optical cable or changing the position of a terminal, a different number of optical cables are laid and the old optical cable is discarded.

However, in recent years, with the spread of the optical communication network, the application area of the optical cable has been expanded.
The use of optical fibers with a small number of fibers has been expanded, and the number of occasions of laying congested in the interior of a building with complicated installation locations or in a place where other cables including copper cables are intermingled has increased. In such a place, when it is necessary to change the terminal position of the existing small-fiber-count optical cable, the work of replacing the optical cable is very complicated, and the work of changing the existing wiring route is
There has been a demand for a technique in which an unnecessary part is left as it is, and only a changed part is replaced and connected. At this time, using a conventional connection box had many obstacles in terms of the cost of the box, securing and maintenance of the supporting place for the box, and the like.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has a small-sized connection portion without using a conventional connection box as a connection point of an optical cable having a small number of fibers. It is an object of the present invention to provide an optical cable connection portion and a connection member having a small number of fibers that can be reduced in weight.

[0006]

According to a first aspect of the present invention, there is provided a connecting portion for a small-fiber-count optical cable in which a low-fiber-count optical fiber and a tensile strength member are integrated by a thermoplastic resin coating. The strength members of the optical cable on both sides of the connection portion are connected by a connection member to form a tensile strength holding structure in the longitudinal direction, and the optical fibers on both sides of the connection portion are connected in a state substantially parallel to the strength member, A protective sheath is provided outside the connection member so as to cover the optical cables on both sides of the connection portion.

According to a second aspect of the present invention, in the connecting portion of the optical cable having a small number of fibers according to the first aspect, the connecting member holds the strength members on both sides of the connecting portion, respectively. It is characterized by having.

According to a third aspect of the present invention, in the connecting portion of the optical fiber having a small number of fibers according to the second aspect, the strength member accommodating portion is configured as a caulking portion deformable by an external force. It is assumed that.

According to a fourth aspect of the present invention, in the connecting portion of the optical fiber having a small number of fibers according to the second aspect, the strength member housing portion is configured as a fastening portion with a screw for pressing the strength member. It is characterized by the following.

According to a fifth aspect of the present invention, in the connecting portion for an optical cable having a small number of fibers according to any one of the first to fourth aspects, the connecting member includes an optical fiber housing portion for housing the optical fiber connecting portion. It is characterized by being integrally provided.

According to a sixth aspect of the present invention, there is provided a connection member for an optical cable having a small number of fibers, wherein a strength member housing portion for connecting the strength members on both sides of the connection portion and a connection portion of the optical fiber are housed. And an optical fiber accommodating portion.

According to a seventh aspect of the present invention, in the connecting member for an optical cable having a small number of fibers according to the sixth aspect, the strength member accommodating portion at least partially forms a caulking portion deformable by an external force. It is characterized by the following.

According to an eighth aspect of the present invention, in the connecting member for an optical cable having a small number of fibers according to the sixth aspect, a screw for tightening a strength member inserted into the strength member housing portion is provided. It is.

[0014]

FIG. 1 is a view for explaining a first embodiment of a connecting member for an optical cable having a small number of fibers according to the present invention. FIG. 1A is a perspective view of the connecting member, and FIG. 1B is a sectional view taken along line AA of FIG. 1A, and FIG. 1C is a perspective view for explaining an example of an optical cable having a small number of fibers. In the figure, 1
Is a connection member, 2 is a support wire accommodation portion, 2a is a support wire positioning portion, 3 is an optical core wire accommodation portion, 4 is a support wire fixing screw, 5 is an optical cable, 5a is an optical core wire, 5b is a support wire, 5c, 5d is a sheath, 5e is a neck, and 5f is a notch.

As shown in FIGS. 1A and 1B, the connecting member 1 is made of a metal material such as brass, in particular, a light metal such as an aluminum alloy, or HDPE (high-density polyethylene).
The support wire housing 2 and the optical fiber housing 3 are formed as concave grooves in the longitudinal direction.
The support wire fixing screw 4 is screwed into a screw hole formed in the connecting member 1 so as to be screwed toward the support wire positioning portion 2a formed in the support wire accommodation portion 2.
For fixing the support wire. The support line positioning part 2a formed in the support line accommodation part 2 is provided so that the support line can be easily accommodated in the support line accommodation part 2.
The support line is formed as a concave groove facing the support line fixing screw 4 so that the support line does not escape from the support line fixing screw 4 by tightening of the support line fixing screw 4. Further, if the screwing direction is set appropriately, it is not necessary to further form a concave groove of the support line positioning portion 2a in the concave groove of the support line housing portion 2, and the concave groove itself of the support line housing portion 2 is supported line positioning. It may be used as a unit. In the case where a synthetic resin is used as the material of the connection member 1,
If it is not preferable in terms of strength to directly form a screw hole in the connection member 1, a metal component having a screw hole such as a metal nut may be embedded when the connection member 1 is formed.

The optical fiber housing 3 is provided to protect the optical fiber connecting portion and the optical fibers before and after the optical fiber connecting portion from external force, and is formed in parallel with the support wire housing 2. As described later, when the tension is applied to the optical cable in a state in which the support wire of the optical cable is fixed to the support wire accommodating portion 2, a bending strain that causes a problem to the optical core wire is applied to the optical cable. That is, the distance is set such that the optical fiber is accommodated at a position substantially parallel to the axis of the support line.

FIG. 1C is a perspective view for explaining an example of a small-fiber-count optical cable connected by the connecting members described with reference to FIGS. 1A and 1B. An example of this optical cable is
It is a self-supporting optical cable, in which two optical fibers 5a are vertically arranged and a sheath 5c is provided. As the support wire 5b as a tensile strength member, a metal wire such as a steel wire or a steel twisted wire, a metal twisted wire, or a carbon fiber or an aromatic polyamide-based synthetic fiber (for example, Kevlar (registered trademark)) is known. ), The sheath 5d of the support wire 5b is provided. The sheath 5c, the sheath 5d, and the neck 5e are integrally formed so that the sheath 5c and the sheath 5d are connected by the neck 5e. The notch 5f formed in the sheath 5c of the optical fiber 5a is formed so that the sheath 5c can be easily cut open and the optical fiber 5a can be easily taken out.

FIG. 2 is a view for explaining a connecting portion using the connecting member described with reference to FIG. 1. FIG. 2 (A) is an explanatory view of a connected state, FIG. 2 (B) is an external view, FIG. (C), (D),
FIG. 2E is a cross-sectional view taken along line CC, DD, and EE in FIG. In the figure, the same parts as those in FIG. 6 is an optical cable, 6a is an optical fiber, 6b is a support wire, 6c and 6d are sheaths, 6e is a neck, 7 is an optical fiber connection part, and 8 is a protective sheath.

In the connection section in FIG. 2, the optical cable described in FIG. 1C is connected by the connection member shown in FIG. Support wires 5 from left and right optical cables 5 and 6
b and 6b are fastened and fixed by two support line fixing screws 4 in the support line accommodation section 2 of FIG. The number of support wire fixing screws 4 is not limited to two, and an appropriate number that can maintain the fixing strength is used.
The optical fibers 5 a and 6 a from the left and right optical cables 5 and 6 are connected as an optical fiber connection unit 7. The optical fibers 5a and 6a may be fusion-spliced, and the optical fiber connecting portion 7 may be configured by covering with a protective cover, or a structure in which the ends of the optical fibers are butted by a mechanical splice and optically coupled. An appropriate connection structure can be adopted. The difference from the conventional connection structure between optical cables is that no extra length is taken. The optical fiber connecting portion 7 is housed in the optical fiber housing 3 shown in FIG.

As shown in FIG. 2B, the protective sheath 8 is put on the connection portion where the optical cables on both sides are connected. The protective sheath 8 uses, for example, a heat-shrinkable tube. Before connecting the optical cable, in advance, through one of the optical cable and heat shrink tube, after the connection work is completed, cover the heat shrink tube and heat shrink to form a protective exterior, protecting the entire connection part I have.

As shown in FIG. 2 (C), the protective armor 8 is in close contact with the optical cable to protect rainwater and the like from entering from the end. Further, as shown in FIG. 2 (D), the support wire is fastened by a support wire fixing screw and fixed to the connecting member, and is protected by the protective sheath 8 together with the optical fiber. In FIG. 2 (E), the connection portion of the optical fiber is a protective sheath 8
Is shown to be protected.

A specific example of the first embodiment will be described. The connecting member 1 is formed by using a columnar member made of an aluminum alloy and forming a support wire housing 2 and a connection housing 3. The total length is about 80 mm, the height is about 15 mm,
The width is about 10 mm. The support wire is provided with a mechanism to be held down by the support wire fixing screw 4 as described above. The optical fiber accommodating portion 3 accommodates a fusion spliced portion of an optical fiber formed in a substantially cylindrical shape having a length of about 40 mm and a diameter of about 5 mm.

An optical cable having a small number of fibers described with reference to FIG. The two optical fibers of this optical cable have an outer diameter of 0.3 mm.
An outer diameter of 0.1 mm in which a 125 mm optical fiber is coated with a protective coating.
It is an optical fiber of 25 mm, and the height of the cable main body provided with a sheath surrounding the optical fiber is 4 mm. Support line 5b
Is a steel wire having a diameter of 1.2 mm, and is provided with a sheath and a common sheath at a height of 8 mm. At the ends of the two optical cables 5 and 6, the support wire and the cable main body including the optical fiber are separated over about 10 cm, and 5 cm from the end.
The covering of the supporting wires 5a and 6a having a small length is removed. After the optical fibers are fusion-spliced by a well-known method and a protective cover is applied, the optical cables on both sides including the connection points are linearly supported, and the support wires 5b and 6b do not overlap, and the connection points of the optical fibers are not overlapped. The support lines 5b and 6b are cut such that an interval of about several mm is left near the position corresponding to the above. Next, the optical fiber cable connecting portion 7 is housed in the optical fiber housing portion 3, the support wires 5b, 6b are housed in the support wire housing portion 2, and the both sides are pulled lightly so that the cable body sides on both sides naturally extend. While the optical fibers 5a, 6
a is substantially linear, and the support lines 5b and 6b on both sides are arranged in a straight line. In this state, the support wire fixing screw 4 is turned to connect the support wires 5b, 6b to the connection member 1.
Is fixed. Then, the heat-shrinkable tube previously covered on the optical cable is moved onto the connecting member 1,
Heat shrink to form a protective sheath.

By configuring the connecting portion in this manner, a very small connecting portion having a length of about 150 mm or less, a sectional height of about 17 mm, and a width of about 12 mm can be formed, and both aesthetic appearance and wind pressure load are good. Since a large structure such as a box is not required, there is no need to support the building, and the entire connection work can be reduced.

FIG. 3 is a view for explaining a second embodiment of a connecting member for an optical cable having a small number of fibers according to the present invention. FIG. 3 (A) is a perspective view of the connecting member, and FIG. 3 (B). 3C is a side view, and FIGS. 3C, 3D, and 3E are lines CC of FIG.
It is sectional drawing in the -D line and the EE line. In the figure, 1 is a connection member, 2 is a support wire housing, and 3 is an optical fiber wire housing.

In this embodiment, the connecting member 1 is provided with the support wire housing 2 at both ends and the optical fiber wire housing 3 at the middle. The support wire accommodating portion 2 is made of a material that is plastically deformed so as to form a space portion having a substantially U-shaped cross section, for example, a metal material, and is integrated with the optical core wire accommodating portion 3. I have. When the support wire of the optical cable is housed and fixed in the support wire housing portion 2, the optical fiber housing portion 3 may be subjected to bending strain that causes a problem to the optical fiber housed in the optical fiber housing portion 3. In such a manner, the axis of the support wire housing 2 and the axis of the optical fiber wire housing 3 are provided at positions where they are set. The cross-sectional shape of the optical fiber housing 3 is selected to be a shape suitable for housing the connection portion of the optical fiber. In this embodiment,
It is formed to accommodate two mechanical splices.

FIGS. 4A and 4B are diagrams for explaining a connecting portion using the connecting member described with reference to FIGS. 3A and 3B. FIG. 4A is a plan view of a connected state, FIG. 4C and 4D are cross-sectional views taken along lines CC and DD in FIG. 4B. In the figure, the same parts as those in FIG. Reference numerals 5 and 6 denote optical cables, and the reference numerals of the respective parts are the same as those described with reference to FIGS. 9 is a mechanical splice.

The optical cable described with reference to FIG. 1C is also connected by the connecting member 1 at the connecting portion shown in FIG. The supporting wires 5b, 6b from the left and right optical cables 5, 6 are shown in FIG.
Are accommodated in the support line accommodation section 2 and the support line accommodation section 2 is caulked and fixed. The optical fibers 5 a and 6 a from the left and right optical cables 5 and 6 are connected by a mechanical splice 9 and housed in the optical fiber housing 3. The mechanical splice 9 may be adhered to the optical fiber housing 3 with an adhesive or the like so that the mechanical splice 9 does not rattle with respect to the optical fiber housing 3. As described above with reference to FIG. 2B, the protective sheath 8 is provided on the connection portion where the optical cables on both sides are connected in this manner.
, But the description is omitted because it is the same as FIG.

A specific example of the second embodiment will be described. The connection member 1 was produced by press molding using a 1 mm thick stainless steel plate. The optical fiber housing 3 has a length of several mm so that the distance between the support fiber and the optical fiber does not greatly increase and bending strain is applied to the optical fiber.
It is formed so that it can be arranged close to the following. In this specific example, a mechanical splice manufactured by 3M Corporation was used as the mechanical splice.

In this specific example, the supporting wires of the two optical fibers having a small number of fibers to be connected are cut in advance by several cm shorter than the optical fibers, so that the optical fiber connecting work does not become an obstacle near the optical fiber connecting point. I did it. The two mechanical splices having a length of 50 mm are connected to a 70 mm long optical core housing 3.
And the cable jacket is protected inside the side wall together with the removed optical fiber. Next, the support wire is accommodated in the support wire accommodation portion 2, and the optical fibers 5a, 5b are lightly pulled to both sides so that the cable body sides on both sides are naturally extended.
6a is made substantially linear, and the support lines 5b and 6b on both sides are arranged in a straight line. In this state, the support wires 5b and 6b are fixed to the support wire housing 2 by strongly caulking the support wire housing 2 with a nipper or the like.

FIG. 5 is a perspective view for explaining a third embodiment of a connecting member for an optical cable having a small number of fibers according to the present invention. In the figure, 1 is a connection member, 2 is a support wire accommodation part, 3 is an optical fiber accommodation part, and 10 is a cut.

Also in this embodiment, the connection member 1 is formed by bending a single metal plate. The shape of the bend is
The support wire accommodating portion 2 formed in the upper portion has an S-shape in cross section, and is bent into a substantially circular shape so that a support wire (not shown) can be inserted and caulked. Notches 10 are formed at a plurality of places in consideration of ease of caulking. The optical fiber core housing 3 formed at the lower part has a connection part for optical fibers (not shown) and a space for housing optical fibers before and after the optical fiber core, and has a substantially circular cross section. But,
An appropriate cross-sectional shape may be used depending on the shape and size of the optical fiber connection portion to be housed. The method of connecting an optical cable using this connection member is similar to that of the connection member of the second embodiment, in which the optical fibers are connected to each other, and the optical fiber connection portion is housed in the optical fiber housing portion 3. Then, the support wire is accommodated in the support wire accommodation portion 2, the support wire accommodation portion 2 is crimped, and the support wires of the optical cables on both sides are connected via the connection member 1.

FIG. 6 is a view for explaining a connecting portion using a connecting member according to a fourth embodiment of the present invention.
FIG. 6A is an explanatory view of a connection state, and FIG. 6B is an external view. In the figure, the same parts as those in FIGS. 11 is a caulking part.

In this embodiment, the connecting member 1 is provided only with a portion for accommodating the support wire, and is not provided with a portion for accommodating the optical fiber. That is, the connecting member 1 is a metal pipe and a support wire accommodating portion. The supporting wires 5b and 6b inserted into the connecting member 1 are fixed by caulking a metal pipe. Caulking part 11
There may be one place for each support line, but a plurality of places can increase the fixing strength. From the periphery of the parallel optical fiber connection portion 7 to the ends of the optical cables 5 and 6, the connection portion is formed by covering the protective sheath 8.

In the connecting member according to the above-described embodiment, the axes of the supporting line accommodating portions for fixing the optical cables on both sides are arranged in a straight line so that the tensile members are connected linearly in series. This is not necessary, and the support wire housing portion may be configured so that the axial position of the support wire housing portion is shifted and the strength members are partially arranged in parallel and fixed to the connection member. The support wire can be fixed to the connection member at a longer distance, and the reliability of the connection can be improved.

In the present invention, the number of optical fibers to be connected is not limited to two. One core or three or more cores may be used, but it is effective for connecting an optical cable having a small number of cores because the core wire connecting portion is not required to be large. Further, the present invention can also be applied to an optical fiber having a core connecting portion formed by collective connection, such as a tape-shaped optical fiber core.

[0037]

As is apparent from the above description, according to the present invention, the cable connecting portion can be reduced in size, diameter, weight and simplification, so that the cost is reduced and the workability is improved. Is possible. In addition, since the connection is made without providing the extra length of the optical fiber, a meat, tray, etc. for storing the extra length is not required, no connection box is required, and the optical cable can be connected at any position. It is. In particular, even with an optical cable using a small-diameter, low-tensile strength member such as a drop cable, there is an advantage that it is possible to connect in a free space without having to fix and hold the connecting portion to a utility pole or a building.

[Brief description of the drawings]

FIG. 1A is a view for explaining a first embodiment of a connecting member of the present invention. FIG. 1A is a perspective view of the connecting member, and FIG.
FIG. 1B is a cross-sectional view taken along line AA of FIG. 1A, and FIG. 1C is a perspective view illustrating an example of an optical cable having a small number of fibers.

2 (A) is an explanatory view of a connection state, FIG. 2 (B) is an external view, and FIG. 2 (C) is a view for explaining a connecting portion using the connecting member described in FIG. , (D) and (E) show FIG.
It is sectional drawing in the CC line, DD line, and EE line of (B).

3 (A) is a perspective view of the connecting member according to a second embodiment of the present invention, and FIG.
(B) is a side view, and FIGS. 3 (C), (D) and (E) are FIG.
It is sectional drawing in the CC line, DD line, and EE line of (B).

4 (A) is a plan view of a connection state, FIG. 4 (B) is a side view, and FIG. 4 (C) is a view for explaining a connection portion using the connection member described in FIG. , (D) are cross-sectional views taken along lines CC and DD in FIG. 4B.

FIG. 5 shows a third connection member of the optical fiber having a small number of fibers according to the present invention.
It is a perspective view for describing Embodiment of this invention.

6A and 6B are diagrams for explaining a connection portion using a connection member according to a fourth embodiment of the present invention, wherein FIG. 6A is an explanatory view of a connection state, and FIG. 6B is an external view. is there.

[Description of Signs] 1 ... Connecting member, 2 ... Support line accommodation section, 2a ... Support line positioning section, 3 ... Optical core line accommodation section, 4 ... Support line fixing screw, 5, 6
... optical cable, 5a, 6a ... optical core wire, 5b. 6b: Supporting wire, 5c, 5d, 6c, 6d: Sheath, 5e, 6e: Neck, 5f: Notch, 7: Optical fiber connection, 8: Protective armor,
9 ... mechanical splice, 10 ... cut, 11 ... caulking part.

Claims (8)

[Claims] 1. A connecting portion of an optical cable having a small number of optical fibers, wherein the optical fiber having a small number of optical fibers and a tensile strength member are integrated with a thermoplastic resin coating, wherein the tensile strength members of the optical cable on both sides of the connecting portion are connecting members. To form a tensile strength holding structure in the longitudinal direction, optical fibers on both sides of the connecting portion are connected in a state substantially parallel to the tensile strength member, and optical cables on both sides of the connecting portion outside the connecting member. A connection portion for an optical cable having a small number of fibers, wherein a protective sheath is covered so as to cover the optical cable. 2. The connection section for an optical cable having a small number of fibers according to claim 1, wherein the connection member has a strength member receiving section for locking the strength members on both sides of the connection section. 3. The connection section for an optical cable having a small number of fibers according to claim 2, wherein the tensile strength member housing section is configured as a caulking section deformable by an external force. 4. The connection portion for an optical cable having a small number of fibers according to claim 2, wherein the strength member housing portion is configured as a fastening portion with a screw pressing the strength member. 5. The connection section for an optical cable having a small number of fibers according to claim 1, wherein the connection member integrally includes an optical fiber housing section for housing the connection section of the optical fiber. 6. A connecting member for an optical cable having a small number of fibers, comprising: a strength member housing portion for connecting the strength members on both sides of the connection portion; and an optical fiber housing portion for housing the connection portion of the optical fiber. A connection member for an optical cable having a small number of fibers, comprising: 7. The connection member for an optical cable having a small number of fibers according to claim 6, wherein the strength member housing portion forms a caulking portion which can be deformed at least partially by external force. 8. A screw for tightening a strength member inserted into the strength member housing portion.
2. A connection member for an optical cable having a small number of cores according to item 1.