JP2000249841A - Holding structure of optical fiber end - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a holding structure of optical fiber ends capable of improving working efficiency when connecting an optical fiber cable to a connecting box and is capable of decreasing the number of parts and lessening transmission loss. SOLUTION: The holding structure of the optical fiber ends is applied at the time of connection of the ends of the optical fiber cables 2 having the plural optical fibers 3 and tension members 5 at their axial centers to each other within the connecting box and is provided with optical fiber holding members 1 having elastic cylindrical body parts 6 fitted to the optical fiber coating cables 2 peeled of sheathes 4, fiber guide cylinders 8 which are integral with these elastic cylindrical body parts 6 and individually guide the optical fibers 3 and through-holes 9 through which the tension members 5 are passed when the elastic cylindrical bodies 6 are fitted to the optical fiber cables 2. The individual optical fibers 3 are inserted into the fiber guide cylinders 8 and the tension members 5 are inserted into the fiber guide cylinders 8 and in this state, the elastic cylindrical body parts 6 are fitted onto the optical fiber cables 2 peeled of the sheathes 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber end holding structure applied when connecting the ends of optical fibers to each other in a connection box.

[0002]

2. Description of the Related Art Hitherto, when an end of an optical fiber is connected in a connection box, an optical fiber holding structure as disclosed in Japanese Patent Application Laid-Open No. 6-208025 has been adopted. FIG.
As shown in FIG. 7 and FIG. 7, the optical fiber cable 36 is composed of a tension member 39 at the shaft core and a tension member 39.
And a groove 3 formed in the longitudinal direction of the outer peripheral surface.
1 and a groove 31 of the spacer 30
And an outer cover 37 covering the spacer 30.

The optical fiber holding structure A includes a short tube 33 fitted to an optical fiber 32 being separated from the groove 31 of the spacer 30, and an insulating member for holding the short tube 33 around the spacer 30. And an adhesive tape 34. Further, a holding member 35 for fixing an outer cover 37 of the optical fiber cable 36 to a frame provided at one end of a connection box (not shown), and an optical fiber 32 wound between the holding member 35 and the spacer 30 And a protective tape 38 for preventing damage to the tape.

As shown in FIG. 7, a plurality of optical fibers 32 are inserted into a short tube 33. The short tube 33 is fitted into the groove 31 of the spacer 30, and is fixed to a predetermined dimension inward from the end surface of the outer cover 37 of the optical fiber cable 36 that coincides with the inner end surface of the holding bracket 35. Thereby, the optical fiber 32 can be prevented from being curved and separated from the groove 31 of the spacer 30 at a sharp angle, and an increase in transmission loss can be prevented. In FIG. 7, four short tubes 3 are shown.
Although the fitting state of No. 3 is illustrated, the number of fittings is appropriately changed as needed. In addition, short tube 3
The outer diameter of 3 is set such that a part of the outer peripheral surface protrudes from the groove 31. Thereby, the short tube 33
Is securely fixed on the outer surface of the spacer 30 by the insulating adhesive tape 34.

[0005]

In the above-mentioned conventional optical fiber holding structure A, a plurality of optical fibers 32 separated from the groove 31 of the spacer 30 in the connection box are covered with a short tube 33 made of plastic or rubber. After
An insulating adhesive tape 34 is wrapped around and fixed to the groove 31 formed around the outer periphery of the spacer 30. After covering the optical fiber 32 with the short tube 33, an appropriate position is , And the insulating adhesive tape 34 must be wound.

However, when the number of optical fibers 32 is large, it is difficult to hold an appropriate portion by hand.
It is necessary to wrap the insulating adhesive tape 34 with the other hand while holding down the optical fiber 32 with one hand, and there is a problem that workability is poor. Further, when the number of the short tubes 33 increases in accordance with the number of the optical fibers 32, the number of components increases, and there is a problem that the workability is further reduced in combination with the winding operation of the insulating adhesive tape 34.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide an optical fiber end holding structure which has a small number of parts, is excellent in workability, and can reduce transmission loss.

[0008]

SUMMARY OF THE INVENTION The above objects of the present invention can be applied to the case where the ends of an optical fiber cable having a plurality of optical fibers and a tension member of its axis are mutually connected in a junction box. In the holding structure of the optical fiber end portion, an elastic tubular body fitted to the optical fiber cable with the outer skin stripped, and a fiber guide tube integrated with the elastic tubular body and individually guiding the optical fiber. An optical fiber holding member provided with a through hole for penetrating the tension member when the elastic tubular body is fitted to the optical fiber cable. Can be solved by

According to the optical fiber end holding structure having the above-described structure, the elastic cylindrical portion of the optical fiber holding member is fitted to the optical fiber cable, and each optical fiber is inserted into the fiber guide tube of the optical fiber holding member. By doing so, the optical fiber can be branched from the position guided by the spacer without bending or twisting. Further, since the tension member protrudes from the through hole, the optical fiber cable and the holding structure can be stably held in the connection box by fixing the tension member in the connection box. Therefore, it is possible to obtain an optical fiber end holding structure having a small number of components and excellent workability.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical fiber end holding structure to which the present invention is applied will be described below in detail with reference to FIGS. FIG. 1 is a partially enlarged sectional view of a connection box showing a holding structure of an optical fiber end portion of the present embodiment, FIG. 2 is a perspective view showing a holding structure of an optical fiber end portion in FIG. 1, and FIG. FIG. 4 is a perspective view showing the configuration of the fiber holding member, and FIG.
Front view showing the appearance shape of the optical fiber holding member in the
FIG. 5 is a partially cutaway side view showing the optical fiber holding member in FIG.

As shown in FIG. 1, the optical fiber end holding structure according to the present embodiment has an extra length in which the ends of the individual optical fibers 3 constituting the optical fiber cable 2 are provided in a cylindrical connection box 11. It is applied when connecting inside the storage case 12. The connection box 11 is for linearly connecting or branching the ends of the optical fiber cable 2 inserted from both ends, and includes an end face plate 13 provided at both ends and an optical fiber cable 2. And an internal frame 14 for holding the connection portion. Then, one end of the optical fiber holding member 1 for forming the optical fiber end holding structure of the present embodiment is fitted to the end of the optical fiber cable 2, and the other end of the optical fiber cable 2 is tensioned from the other end. The member 5 is inserted.

More specifically, as shown in FIG. 2, the optical fiber cable 2 has the same configuration as the conventional one, and the individual optical fibers 3 are covered with an outer sheath 4, and the optical fibers 3 are not shown. The spacer 30 (see FIG. 6) is fitted into the groove, and the tension member 5 is provided on the axis of the spacer. Therefore, the optical fiber holding member 1 can branch the individual optical fibers 3 while holding the end of the optical fiber cable 2.

As shown in FIGS. 2 to 5, the optical fiber holding member 1 has an elastic cylindrical body 6 fitted to the end of the spacer.
A fiber guide tube 8 provided in an end face plate 7 for closing one end of the elastic tubular body 6, and a through hole 9 through which the tension member 5 passes. As shown in FIG. 5, the inside of the elastic tubular portion 6 is hollow, and its inner diameter is covered with the outer sheath 4 of the optical fiber cable 2 peeled off, in other words, with the optical fiber 3 fitted into the groove of the spacer. It is set so that it can be fitted. The arrangement position and the number of the fiber guide tubes 8 correspond to the positions and the number of the groove portions provided in the spacer, and the through hole 9 is opened at the center of the end face plate 7.

Then, the individual optical fibers 3 are connected to the connection box 11.
When connecting inside, the outer sheath 4 of the optical fiber cable 2 is peeled off, and the spacer is cut to a desired length. Next, the optical fiber 3 is cut to a length required for connection, and the tension member 5 is cut to a length longer than the spacer. Next, the tension member 5 is inserted into the through-hole 9, and the individual optical fibers 3 are inserted one by one into the fiber guide tube 8 corresponding to the position. It is put on the part.

Accordingly, the individual optical fibers 3 are branched from the optical fiber cable 2 in a state where there is no sharp bend, no disorder in the arrangement, and no twist, etc.
You can connect to The tip of the tension member 5 protruding from the through hole 9 is inserted into the tension member fixing portion 15 (see FIG. 1). Therefore, one end of the optical fiber cable 2 is fixed by the end face plate 13 and the internal frame 14, and the tension member 5 is supported by the tension member fixing portion 15, so that the vibration at the position where the optical fiber holding member 1 is covered, etc. Prevented fiber guide tube 8
The optical fiber 3 pulled out of the optical fiber is stably held.

As described above, the structure for holding the end of the optical fiber according to the present embodiment includes the optical fiber holding member 1 at the end of the spacer.
The individual optical fibers 3 can be branched without being twisted or crossed by merely covering them, and can be pulled out and connected to the extra length storage case 12. Therefore, no troublesome work such as covering a short tube on each of the optical fibers 3 constituting the optical fiber cable 2 or winding an insulating adhesive tape is required, thereby improving workability and reducing the number of parts. Can be. Further, since the optical fiber 3 is not bent sharply and hardly vibrates,
Transmission loss due to bending and vibration can be reduced.

In the above-described embodiment, the elastic cylindrical portion 6 is formed in a cylindrical shape. However, the elastic cylindrical portion 6 may be formed in a rectangular shape, and can be freely changed according to the shape of a spacer or the like.
The inner diameter of the elastic tubular portion 6 is also changed according to the outer diameter of the optical fiber cable 2 and the spacer. In addition, the fiber guide tube 8
Can be changed according to the number of optical fibers 3 and the like. That is, a plurality of types of optical fiber holding members 1 in which the inner diameter of the elastic cylindrical portion 6 and the number of fiber guide tubes 8 are different.
May be prepared and used as appropriate. In this case, there is no problem even if the fiber guide tube 8 is empty.

[0018]

As described above, the structure for holding the end of the optical fiber according to the present invention comprises an elastic tubular body fitted on the optical fiber cable whose outer sheath has been peeled off, and an integral unit with the elastic tubular body. An optical fiber holding member is provided which has a fiber guide tube for individually guiding optical fibers and a through hole for penetrating the tension member when the elastic tube is fitted on the optical fiber cable. Therefore, the optical fiber cable is fitted with the elastic tubular body, and the individual optical fibers are inserted into the fiber guide tube, whereby the optical fiber is branched from the position guided by the spacer without being bent or twisted. be able to. Therefore, workability when connecting the optical fiber to the connection box can be improved, and the number of parts can be reduced. Further, since the optical fibers are connected in the connection box without being sharply bent or twisted, transmission loss due to connection, vibration, or the like can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part of a connection box showing an optical fiber end holding structure according to the present invention.

FIG. 2 is a perspective view of a main part showing a holding structure of an optical fiber end in FIG. 1;

FIG. 3 is a perspective view showing a configuration of an optical fiber holding member in FIG.

FIG. 4 is a front view of the optical fiber holding member in FIG.

FIG. 5 is a partially cutaway side view of the optical fiber holding member in FIG. 3;

FIG. 6 is a perspective view showing a conventional optical fiber holding structure.

FIG. 7 is a sectional view in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical fiber holding member 2 Optical fiber cable 3 Optical fiber 4 Outer sheath 5 Tension member 6 Elastic cylinder part 7 End plate 8 Fiber guide cylinder 9 Through hole 11 Connection box 14 Internal frame 15 Tension member fixing part

Claims (1)

[Claims] 1. A holding structure for an end portion of an optical fiber, which is applied when connecting ends of an optical fiber cable having a plurality of optical fibers and a tension member having a shaft core to each other in a connection box, An elastic tubular body fitted on the optical fiber cable from which the optical fiber cable has been peeled off, a fiber guide barrel integrated with the elastic tubular body and individually guiding the optical fibers, and the elastic tubular body covered with the optical fiber cable An optical fiber holding member, comprising: an optical fiber holding member having a through hole through which the tension member passes when fitted.