JP3942725B2 - Optical cable branching method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical cable branching method.
[0002]
[Prior art]
For example, in the so-called post-branching operation of branching the optical line from the middle of the laid optical cable, the work of drawing the optical fiber (optical fiber core wire) from the optical cable by drawing the optical cable to the target branching position and bending it. I need it. At this time, there are cases where the tension member of the optical cable is cut or not cut, but considering the effect on the actual line, the case where the tension member is not cut is superior in that it does not touch the optical fiber more than necessary. is there.
Further, in view of the demand for multi-core, an optical cable generally has a structure in which a multi-fiber ribbon is housed as an optical fiber, and this type of optical cable is a so-called SZ cable corresponding to a post-branching operation after installation. However, in view of cost and the like, most of the optical cables are mainly unidirectionally twisted in which a multicore tape core wire is wound in one direction and stored.
[0003]
[Problems to be solved by the invention]
By the way, in recent years, the number of cases where the optical fiber branched later is re-branched later is increasing.
As a method of branching optical cables so that they can be branched again,
(1) A method of branching using an SZ cable without cutting the tension member,
(2) There is a method of using a one-way twisted optical cable, cutting the tension member, drawing the extra length of the offset secured in advance to the branch position, bending the optical cable, and taking out the optical fiber.
[0004]
However, in the method (1), there is a disadvantage that the post-branching is impossible at a place where the SZ cable is not laid, and when the SZ cable is laid over the entire optical line, there is a problem that the cost is significantly increased.
In the method (2), when the tension member is cut, the influence on the optical fiber that is not subject to branching is great, and it is necessary to pay close attention to proceed without affecting the optical fiber. There is a problem that workability is reduced. In addition, after installing the optical closure at the tension member cutting position, the extra length of the offset of the optical cable is eliminated, so that it becomes impossible to deal with when re-branching near the optical closure becomes necessary. is there.
[0005]
The present invention has been made in view of the above problems,
(A) It is possible to perform branching work without cutting the tension member by using a one-way twisted optical cable, and to perform branching work efficiently without affecting the line that is not subject to branching.
(B) It is an object of the present invention to provide an optical cable branching method in which an extra length for an offset is secured in an optical cable even after branching work and re-branching work is possible.
[0006]
[Means for Solving the Problems]
In the present invention, an optical cable branching method for branching an optical cable after installation,
An attracting step of removing the outer sheath of the installed optical cable over a range of a target branching position, and drawing a surplus length for an offset reserved in advance in the optical cable to the branching position to form a curved portion in the optical cable; An optical fiber extraction step of taking out the target optical fiber to be branched from the portion of the curved portion from which the outer sheath of the optical cable is removed, and a position where an extra length for the offset is separated from the branch position after the optical fiber extraction step is completed. after moving to and a closure assembly process to complete the optical closure to the branch position, the optical cable branching method, characterized by comprising a solution of the above problems.
[0007]
As an optical cable, various configurations can be employed with respect to the type of optical fiber (optical fiber core) housed therein, the number of optical fiber cores, the twisted form of the optical fiber, and the like.
The optical closure may be partially assembled before the closure assembly process, that is, in the drawing process or the optical fiber extraction process. For example, if the connecting rod and the gripping parts at both ends of the connecting rod are assembled in advance, the optical cable is gripped and fixed by the gripping part, and used to maintain the curved portion formed in the drawing process. Thus, the optical fiber extraction process can be performed efficiently. However, in view of the movement of the extra length for the offset in the closure assembly process, the gripping component needs to be configured to be able to release the gripping and fixing state of the optical cable.
In addition, it is also possible to store separately the optical cable which cut | disconnected the tension member in the optical closure.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of an optical cable branching method of the present invention will be described with reference to the drawings.
[0009]
First, an example of an optical closure applied to the optical cable branching method of the present invention will be described with reference to FIGS.
1 and 2, the optical closure 1 includes a closure sleeve 1a attached to the outside of the optical cable 5, and an elongated plate-like connecting rod 2 disposed along the optical cable 5 in the closure sleeve 1a. A pair of gripping parts 3 and 3 are provided opposite to both ends of the connecting rod 2 in the longitudinal direction. A tray stand 4 is attached to the longitudinal center of the connecting rod 2, and a plurality of thin plate-like trays 6 are stacked on the top plate 4 a of the tray stand 4.
[0010]
The tray stand 4 has a frame shape and has a cable insertion portion 7 therein (see FIG. 3). In the cable insertion portion 7, a portion of the optical cable 5 that does not cut the tension member is removed in the middle, and a portion where the slot 5 a is exposed is accommodated in a state of being pulled through.
Further, the top plate 4a of the tray stand 4 can be rotated by a hinge 4b (see FIG. 3). As shown in FIG. 1, the cable insertion portion 7 can be opened and closed by manually operating the knob 4c. . The tray 6 accommodates an optical connection portion (a fusion connection portion, a connector connection portion, etc.) between the optical fibers 9 taken out from the optical cable 5 or another optical cable 8 separately drawn into the optical closure 1. Further, since the adjacent stacked trays 6 and 6 are rotatably connected by a hinge portion 10 (see FIG. 2), the upper tray 6 is separated from the lower tray 6 and rotated upward. When moved, the work surface of the lower tray 6 can be opened.
[0011]
As shown in FIG. 1, a thin plate-like coupler tray 11 is accommodated in the lower portion of the tray stand 4. As shown in FIG. 3, the coupler tray 11 is guided by a guide portion 12 protruding from the lower portion of the tray stand 4 so as to be horizontally movable, and can be pulled out and stored at the side of the tray stand 4 as shown in FIG. It has become. Further, since the coupler tray 11 housed in the tray stand 4 is positioned below the optical cable 5 in the cable insertion portion 7, it is easy to connect the optical fibers 9 to each other via the optical coupler in the coupler tray 11. Yes, even when the number of optical fibers 9 taken out from the optical cables 5 and 8 is large, it becomes easy to connect these optical fibers 9 while comparing them. The optical fiber 9 taken out from the optical cables 5 and 8 is routed via the coupler tray 11, or the optical fiber drawn from the optical coupler in the coupler tray 11 is drawn into the tray 6, and the optical cables 5 and 8 are inserted into the optical fiber. The optical fiber 9 taken out from is connected. Needless to say, the optical connection portion between the optical fibers 9 taken out from the optical cables 5 and 8 may be directly stored in the tray 6.
The coupler tray 11 configured to be stored in the tray stand 4 can effectively use the volume of the optical closure 1 and can increase the number of cores of the optical closure 1.
[0012]
As shown in FIG. 1, the gripping part 3 includes an I-shaped support part 13 fixed to the connecting rod 2 and a plurality of demon parts 14 screwed to the support part 13. The optical cable 5 or 8 inserted through the component 13 is held and fixed from both sides by a pair of demon components 14 and 14, respectively.
In FIG. 1, the gripping part 3 has two pairs of demon parts 14, 14, and the optical cable 5 that does not cut the tension member is gripped and fixed to one pair of demon parts 14, and the other part of the demon part 14 is held. The optical cable 8 with the tension member cut is held and fixed to the pair. The slot 8 a exposed at the end of the optical cable 8 with the tension member cut is fixed to a slot fixture 15 fixed to the connecting rod 2 between the gripping component 3 and the tray stand 4. The slot 8 a is not inserted into the cable insertion portion 7.
In this optical closure 1, it is not necessary to introduce the optical cable 8 from both sides, and it is possible to introduce the optical cable 8 from only one side as shown in FIGS.
Further, since the demon parts 14 and 14 are both screwed to the bearing part 13 so as to be able to rotate forward and backward, when the space between the pair of demon parts 14 and 14 facing each other is expanded, the optical cables 5 and 8 are connected. The holding and fixing state can be released.
[0013]
Next, an optical cable branching method according to this embodiment will be described.
First, as shown in FIG. 4, an optical cable 17 is laid while securing an extra length 16 for an offset at an appropriate location. In FIG. 4, reference numerals 18a and 18b denote struts, and the optical cable 17 is laid so as to be suspended from a support line 19 installed between the struts 18a and 18b. Further, it is preferable to secure the extra length 16 for the offset in the vicinity of the columns 18a and 18b.
Next, the outer sheath of the optical cable 17 is removed over the range of the target branching position 20 in the vicinity of the column 18a to expose the slot 21a (see FIG. 5), and as shown in FIG. 6 and FIG. The length 16 is drawn from the vicinity of the support column 18a to the branch position 20 to bend the slot exposed portion 21 of the optical cable 17 to form a curved portion 22 (attraction process).
[0014]
Next, as shown in FIG. 8, the target optical fiber 23 (optical fiber core wire) branched from the slot exposed portion 21 of the bending portion 22 is taken out (optical fiber take-out step).
At this time, if the optical closure 1 shown in FIG. 1 is partially assembled and the optical cables 17 at both ends of the bending portion 22 are held and fixed by the holding parts 3 and 3 at both ends of the connecting rod 2, the bending portion 22 is Can be maintained. The bending portion 22 is accommodated in the cable insertion portion 7 or is disposed so as to protrude outside the cable insertion portion 7 by opening the top plate 4a. When the gripping parts 3 and 3 are used, one worker can take out the optical fiber 23, which is significantly larger than the conventional case where a worker for maintaining the curved portion 22 is separately required. It is possible to reduce the cost.
Further, after the optical fiber 23 taken out is cut, an optical connection portion with another optical fiber is accommodated in the tray 6 or pulled into the coupler tray 11 and connected to the optical coupler.
[0015]
Next, the extra length 16 for the offset is moved to the original position (near the column 18a), and the optical closure is completed at the branch position 20 (closure assembly process). As a result, as shown in FIG. 10, the slot exposed portion 21 of the optical cable 17 is unbent and becomes straight. Since the optical cable 17 does not cut the tension member, the length variation hardly occurs in the extra length 16 for the offset after moving to the vicinity of the column 18a.
When the gripping component 3 of the optical closure 1 is used in the optical fiber extraction process, the gripping and fixing by the gripping component 3 on the column 18a side is once released, the extra length 16 is moved to the column 18a side, and then the optical cable 17 is gripped again. The component 3 is held and fixed. At this time, the optical cable 17 can be held at a predetermined position only by re-fixing the optical cable 17 with the gripping component 3 on the support 18a side by maintaining the gripping and fixing state of the optical cable 17 with the gripping component 3 on the opposite side (supporting column 18b). Thus, the connecting rod 2 can be easily attached to the optical closure 1, and the assembly workability of the optical closure 1 is improved. When the optical cable 17 is re-gripped and fixed, the optical cable 17 passes the slot exposed portion 21 through the cable insertion portion 7 so as to be in the same state as the optical cable 5 shown in FIG. At this time, since the slot exposed portion 21 is housed and protected in the tray stand 4, it is possible to prevent inconvenience such as interference of surrounding members with the optical fiber 23 in the slot 21a, and the influence on the actual line can be reduced as much as possible.
In this closure assembly process, the surplus length 16 can be moved to a place other than the vicinity of the column 18a.
[0016]
The optical cable branching method described above can be similarly performed in the vicinity of the support column 18b. When a new branching operation is performed at or near the branching position 20, the branching operation can be similarly performed by using the surplus length 16 secured in the vicinity of the support column 18a.
Also in this new branching operation, it is possible to repeat the branching operation in the same manner by moving the surplus length 16 to a place away from the branching position after the operation.
[0017]
【The invention's effect】
As described above, according to the optical cable branching method of the present invention,
(B) The extra length reserved for the optical cable in advance is drawn to the target branch position by the drawing process and moved to a position away from the branch position after the branching work. Even if it is a branching work, it can be done efficiently without cutting the tension member.
(B) By the above (a), it is possible to perform branching work efficiently without affecting the line (optical fiber) that is not subject to branching.
(C) Since the extra length of the offset moved from the branch position to the position separated from the branch position in the closure assembly process can be used for new branch work, re-branch work can be efficiently performed.
(D) Since the branching work can be performed without cutting the tension member, the influence on the actual line can be reduced, and an excellent effect that the branching work can be advanced efficiently is achieved.
[Brief description of the drawings]
FIG. 1 is an overall perspective view showing an optical closure used in an optical cable branching method according to the present invention.
FIG. 2 is a plan view showing the optical closure of FIG. 1;
FIG. 3 is a front view showing the optical closure of FIG. 1;
FIG. 4 is a diagram showing an embodiment of an optical cable branching method according to the present invention, and is a process diagram showing an installed state of the optical cable.
FIG. 5 is a process diagram showing a process of removing the outer cover of the optical cable to expose the slot in the optical cable branching method of the present embodiment.
FIG. 6 is a process diagram showing a drawing process in the optical cable branching method of the embodiment.
7 is a front view showing a curved portion formed in the drawing step of FIG. 6 in the optical cable branching method of the present embodiment.
FIG. 8 is a process diagram showing an optical fiber extraction process in the optical cable branching method of the present embodiment;
FIG. 9 is a process diagram showing a process of cutting the optical fiber taken out in the optical fiber take-out process in the optical cable branching method of the embodiment.
FIG. 10 is a front view showing the optical cable in the vicinity of the branch position after moving the extra length for the offset in the closure assembly process in the optical cable branching method of the present embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Optical closure, 16 ... Extra length for offset, 17 ... Optical cable, 20 ... Branch position, 21 ... The part which removed the cable sheath of the curved part (slot exposed part), 22 ... Curved part, 23 ... Optical fiber (light Fiber core).

Claims (1)

An optical cable branching method for branching an optical cable (17) after installation,
The outer sheath of the installed optical cable is removed over the range of the target branching position (20), and the extra length (16) reserved in advance for this optical cable is drawn to the branching position , and a curved portion ( 22) forming a drawing step;
From the portion (21) by removing the outer skin of the optical cable of the bending portion, and an optical fiber taking-out step of taking out the object of the optical fiber (23) that branches,
A closure assembly process for completing the optical closure (1) at the branch position after moving the extra length of the offset to a position spaced from the branch position after completion of the optical fiber extraction step ;
An optical cable branching method comprising the steps of:

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