JPS6054646B2 - Method for accommodating extra core length of optical fiber cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for accommodating extra core length of connected optical fiber cables.

When connecting optical fiber cables, be sure to keep excess core wires before and after the fiber connection because it is necessary to perform the work at a distance from the axis of the cable due to the arrangement of the connection jig and reinforcement work at the connection. produce length. It is also necessary to secure the necessary extra length for reconnecting and repairing the splice, but this extra length is determined by the allowable bending radius (hereinafter referred to as allowable bending radius) that can be given to the fiber due to the characteristics of the optical fiber. It must be processed by bending more than that. Therefore, it is necessary to reduce the overall size while ensuring an allowable bending radius, and several methods have been invented, one of which is the conventional method shown in Figure 1. The invention overcomes the drawbacks of conventional methods. First, the conventional method will be explained. In Fig. 1, 1 and 1' are the outer sheaths of the optical fiber cables, 2 and 2' are the optical fiber cores, 3 is the connection part of the optical fiber cores, and 4 and 4' are the optical fiber cables 1, respectively.
, 1' are tension members, 5 is a connection sleeve of the tension member, 6 is a retainer of the connecting portion 3, and the retainer 3 is held by the connecting portion sleeve 5 of the tension member. Reference numeral 7 denotes a protective cylinder for the connection portion, and 8 and 8' denote supporters of the protective cylinder 7, which are supported by the cable sheaths 1 and 1', respectively.

Reference numeral 9 denotes a sheath connecting cylinder, which is connected to the cable jackets 1 and 1', respectively.

Next, a conventional connection method will be explained with reference to FIG. First, the tension member 4 | 4' is connected by inserting the tension member connecting sleeve 5 from both ends and curling the outer periphery of the connecting sleeve 5 or by pouring adhesive into the hole of the connecting sleeve 5.Next, connect the tension member connecting sleeve 5. A holder 6 is attached to the outer periphery of the optical fiber 5. Next, the core wires 2 and 2'' of the optical fibers to be connected are connected, and the connecting portion 3 is fixed to the holder 6. The extra length of the core wires 2, 2'' is distributed in the longitudinal direction as shown in FIG. 1, and the ends A and A'' are bent by a bending radius greater than the allowable bending radius and accommodated. Next, the supports 8 and 8'' are attached to the cable jackets 1 and 2'', respectively, and the protective cylinder 7 is attached to the outer periphery of the supporters to protect the connection portion and adjust the form of the core wire in the excess length accommodation portion. Next, the connection part is covered with a sheath connection cylinder 9, and both ends of the connection cylinder 9 are connected to the cable jacket 1. The problems with the conventional method are as follows: (1) Although FIG. 1 shows the connection form of one optical fiber for simplicity, in reality, many fibers are connected. In that case, there will always be a difference in the length of the extra length of each core wire, so the core wires 2 and 2'' will converge at the excess length accommodation ends A and A'', and in extreme cases, Sudden bending that is less than the bending radius may occur. (2) There are few places that hold the optical fiber, so vibrations or movement of the core (when the cable expands or contracts due to temperature differences, etc.)
(Movement of the core wire) may cause the surplus length storage form of the core wire 2 to collapse, or vibration may cause the core wire to wear. The present invention
The purpose is to solve these problems (1) and (2), and specifically, to provide a method that can completely hold multiple locations of the extra length core wire without causing the excess length storage end to sag. It is something.
Next, the structure of the present invention will be explained with reference to FIGS. 2 to 6.

Here, Fig. 2 is a structural sectional view, Fig. 3 is a sectional view taken along A-N in Fig. 2, Fig. 4 is a sectional view taken along B-B'' in Fig. 2, and Fig. 5 is a sectional view taken along
Part of the detailed view of the figure, Figure 6, is shown in the rest. This is a developed view of the long storage space. 1
is the outer sheath of the optical fiber cable, 2 is the optical fiber core, 3
The connecting parts 4 and 4'' of the optical fiber cable are respectively the tension member 5 of the optical fiber cable, the connection sleeve of the tension member, and the reference numeral 10 a spacer for holding the extra length of the cable (hereinafter referred to as ".").
It is arranged on the outer periphery of the tension members 4, 4'' connected by a lower spacer).

Reference numeral 11 denotes a guide for the extra length core wire (hereinafter referred to as a core wire guide), and is arranged on the outer periphery of the spacer 10.

The outer circumferential portion of the spacer 10 has a groove 12 for accommodating an end opening for accommodating the extra length of the core wire, a fitting groove 13 for the core wire guide 11, and a housing portion 14 for the core wire connection portion 3, and both ends 15 thereof are , has a conical shape so that the core wire led from the cable end 22 can be lengthened without difficulty. Further, one side wall 16 of the groove 12 has a curved surface (for example, a spherical surface), and the other side wall 17 has a flat surface. Note that the curved surface 16 corresponds to the core wire connection portion accommodating portion 14.
at the side wall in the direction of. Further, the side walls 16 and 17 are connected by a cylindrical portion 18, and the outer diameter D of the cylindrical portion 18 is as small as possible. Further, the core wire guide 11 has core wire receiving holes 19 equally divided near the outer periphery, so that the core wire can be inserted through the slits 20 from the outer periphery. 7 is a protective cylinder for the connection part, 8
are supports of the protective cylinder 7, which are supported by the cable jackets 1 and 1''j, respectively.

Next, the connection method according to the present invention will be explained with reference to the drawings. First, the tension members 4, 4'' are connected with the tension member connecting sleeve 5 (as in the conventional method), and then the spacer 10 is placed over the outer periphery of the tension member.The spacer 10 is divided into two parts in the longitudinal direction of the tension member. The cage is easy to attach.Next, the core wire guide 11 is attached to the outer periphery of the spacer 10.Next, the core wires are connected, and the connecting portion 3 thereof is housed in the accommodating portion 14.Next, the excess length of the core wire is accommodated. However, if we explain the route of the extra-long core wire, as shown in Figure 2, the cable end 2
2, passes through the fiber guide 11, detours around the curved surface 16 of the omitted part shown in FIG. to the end of the cable. As mentioned above, when connecting a plurality of core wires, the position of the end opening for accommodating the core wires will vary due to the uneven length of the core wires, making it difficult to accommodate the surplus length. In the present invention, as shown in FIG. 6, the irregularities in the extra length of the fibers are absorbed by the intermediate fiber guides 1" and 11", that is, the extra lengths are accommodated by wrapping the irregular lengths around the outer periphery of the spacer 10 in a spiral shape. All the core wires can be aligned at the end opening. Therefore, sudden bending of the core wire due to unevenness of the opening can be prevented, and the characteristics of the optical fiber will not be adversely affected. Further, since important points of the extra length core wire 2 are held down by the core wire guide 11, and the spacer wall 16 of the opening part accommodation part is formed into a curved surface, the extra length accommodation form will not collapse due to vibration or movement of the core wire. , there is no wear on the core wire. Furthermore, in FIG. 1, the opening of the bent portion of the core wire is accommodated at the left end of the spacer 10, but if the excess length of the core wire is shortened due to reconnection of the core wire, the grooves 12'', 12'' closer to the connecting portion 3 It is also possible to sequentially move to ``. Therefore, there is a feature that the excess cable length can be accommodated in an orderly manner in any case.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventional surplus length storage device, FIG. 2 is a sectional view of the device according to the present invention, and FIG. 3 is a sectional view of FIG.
FIG. 4 is a cross-sectional view taken along the line B-B'' in FIG. 2, FIG. 5 is a partially enlarged view of FIG. 2, and FIG. 6 is a developed view of accommodating the extra length according to the present invention.

Claims (1)

[Claims] 1. A plurality of circumferential grooves are provided in the length direction to accommodate the extra length of the connected optical fibers, and the optical fibers and the connecting portion are held along the circumference. In a configuration that has a guide and a connection part accommodating part, the optical fiber is detoured from one groove through the guide and the other groove in a loop shape, and is further wrapped around a spacer provided in the groove to accommodate the excess length. , a method for accommodating excess core length of an optical fiber cable. 2. A method for accommodating extra length of an optical fiber cable according to claim 1, characterized in that a hole is provided at the center in the longitudinal direction for passing through the tension member.