JPS63206708A - Pulling end of optical fiber cable - Google Patents

Abstract

PURPOSE:To effectively protect the surplus length part of optical fibers against external force and to reduce the length and diameter of a pulling end by housing the surplus length part of the optical fibers into a protective pipe and supporting the inside of the protective pipe by a surplus length protective frame. CONSTITUTION:The protective pipe 20 having flexibility is provided between a sheath holder 13 at the end of an optical fiber cable 2 and a cap 19 in the outside circumferential part of a plug 17 for connecting the end of a traction wire 16 to an eye nut 18. The optical fiber groups 7, 7... are housed in the protective pipe 20 and the surplus length protective frame 38 which contacts the inside peripheral face of the protective pipe 20 is provided in order to house the surplus length part 7a wound with the respective optical fiber groups to an elliptical shape into the inside space of the protective pipe 20. The external force, which acts diametrally on the pipe 20 during traction, etc., is, therefore, supported by the surface of an arc-shaped supporting plate 39 of the frame 38, by which the surplus length part 7a is effectively protected.

Description

DETAILED DESCRIPTION OF THE INVENTION INDUSTRIAL APPLICATION J Field of the Invention The present invention relates to a pulling terminal used when pulling and laying a fiber-optic cable.

"Prior Art" Generally, when an optical fiber cable is pulled by the so-called tip traction method and installed in a conduit, the outer sheath at the end of the optical fiber cable is It is necessary to tow the vehicle and the central ura tension member in a state where they are integrally fixed.

Conventionally, when the end of an optical fiber cable is fixed and pulled, a pulling terminal such as the one shown in FIG. 7 has been used. This tensioning terminal 50 is constructed by covering the tension member 3 exposed from the optical fiber cable 2 with a sleeve 51 and fixing it by caulking or the like, and by integrally fixing a cylindrical sheath gripper 52 to the sleeve 51. The outer sheath 9 of the optical fiber cable 2 is fixed to the gripper 52.

The sheath gripper 52 inserts an inner tube 53 between the outer sheath 9 peeled off from the end of the optical fiber cable 2 and the inner protector 11 that protects the optical fiber 7 inside the outer sheath 9, and Covering the outside of the sheath 9 with the outer cylinder 54,
The outer sheath 9 is held and fixed by these two cylinders 53 and 54. Further, the pulling line 16 is connected to the tip of the tension member 3 protruding from the sleeve 51 via the coupler 55, and the gap between the tip of the pulling line 16 and the outer surface of the outer sheath 9 of the optical fiber cable 2 is made of polychloride. It is covered with a flexible protection pipe 56 made of vinyl or the like, and the internal space of the protection pipe 56 is partitioned by a connector protection frame 57 attached to the traction line 16, and the optical fiber 7 is placed in the partitioned space. The connected connector 10 is housed at the tip. Then, the eye nut 58 attached to the tip of the towing line 16 is towed as shown by the arrow.

[Problems to be Solved by the Invention] By the way, when providing a sufficient extra length for the optical fiber 7 pulled out from the end of the cable 2 in the above-mentioned tensile terminal 50, it is necessary to provide the optical fiber 7 in the internal space of the protection pipe 56. It is possible to store the extra length, and in this case, the total length of the extra length and the tension end increases. However, during transportation, installation, etc., a long tension terminal becomes cumbersome to handle and causes trouble to the work. For this reason, the tension terminal 50
In order to suppress the overall length from increasing, it is conceivable to store the extra length in a state where it is wound multiple times.

However, when the optical fiber 7 is wound, a problem arises in that the optical fiber 7 is bent when an external force in the radial direction is applied to the protective pipe 56, such as when being pulled inside the conduit. For this reason, it is necessary to protect the extra length in some way, but it is necessary to avoid increasing the outer diameter of the extra length storage part due to the structure for protection, as this will impede towing work, etc. If that's the case.

The present invention was proposed in view of the above circumstances, and it effectively protects the extra length of the optical fiber from external forces, eliminates the problem of lengthening and increasing the diameter, and shortens and reduces the diameter of the tensile terminal. The purpose is to achieve the following.

"Means for Solving the Problems" In order to achieve such an object, the present invention allows the extra length of the optical fiber to be housed in the protection pipe, and also includes a An extra length protection frame is provided to support the inner peripheral surface of the protection pipe. and fixed by connecting members at intervals in the circumferential direction, and a space is formed between the connecting member and the protective pipe, through which a part of the extra length is inserted. do.

"Function" The tensile terminal of the present invention can be stored in a state in which the extra length is wound a plurality of times inside the protective pipe to suppress the lengthening of the tensile terminal. The inner side of the protective pipe is supported by an extra length protection frame to increase the mechanical strength of the protection pipe, and when an external force in the radial direction is applied to the protection pipe during towing, etc., the external force is transferred to the support plate surface of the extra length protection frame. Therefore, the extra length can be effectively protected. and,
In this case, since the extra length protection frame is provided inside the protection pipe, it is possible to maintain the outer surface of the protection pipe in a straight shape without unevenness and to suppress an increase in the outer diameter of the protection pipe. It is.

"Embodiment" Hereinafter, an embodiment of the optical fiber cable tension terminal according to the present invention will be described based on FIGS. 1 to 5.

This tension terminal 1 is used to hold down a multi-core optical fiber cable 2 having up to 1000 optical fibers. First, this optical fiber cable 2 will be explained with reference to FIG. 6.

In this optical fiber cable 2, a tension member 3 is covered with a plastic sheath 4, and a plurality of rod-shaped spacers 5 are arranged around the sheath 4, and a groove 6 formed in the spacer 5 is inserted into the tension member 3. A plurality of optical fibers 7 are housed in each spacer, and a buffer layer 8 made of non-woven fabric or the like is provided to cover the spacers 5.
is covered with an outer sheath 9. As shown in FIG.
The optical fibers 7 are pulled out in a protruding state toward the distal end thereof, and each optical fiber 7 is exposed with a sufficient extra length, and a connector 10, which is a plurality of integrated optical fibers, is connected to the distal end of the optical fiber 7. Hereinafter, the buffer layer 8, spacer 5, and coating 4 inside the outer sheath 9 will be collectively referred to as an inner protector 11.

The tension terminal l attached to such an optical fiber cable 2 has a relatively thin reinforcing tube 12 inserted between an inner protector 11 and an outer sheath 9, as shown in FIG. a sheath gripper 13 that fixes the portion of the outer sheath 9 that is pulled out in a protruding state beyond the inner protector 11; and a sleeve 14 that is attached to the distal end of the tension member 3 and fixed by caulking or the like. A tow line 16 is connected to the sleeve 14 via a coupler 15, and an eye nut 18 is connected to the tip of the tow line 16 via a plug 17. A relatively hard cap 19 is provided on the outer periphery of the plug 17, and a flexible protective pipe 20 made of polyvinyl chloride or the like is placed between the cap 19 and the sheath grip 513. In the internal space of the protective pipe 20, there is an extra length storage section 2 for storing the extra length section 7a of the optical fiber 7.
1 and a connector storage section 22 for storing the connector 10, and the extra length storage section 21 has an extra length section 7 as described later.
An extra length protection frame 38 is provided to protect part a from external force.

To explain these details, the reinforcing tube 12 is as follows:
Between the inner protector 11 and the outer sheath 9, the inner protector 1
The optical fiber cable 2 is inserted into the optical fiber cable 2 so as to protrude from the tip thereof toward the distal end thereof, and a support frame 23 is provided inside the protruding portion.

The support frame 23 consists of a support rod 24 that is provided along the diameter direction of the reinforcing tube 12 and comes into contact with the inner peripheral surface, and a cylindrical portion 25 through which the tension member 3 is inserted. The optical fiber 7 is inserted through the space between the two.

In addition, the outer sheath 9 near the end of the optical fiber cable 2
A shrinkable tube 26 is wrapped around the surface, and the outer sheath 9 and the shrinkable tube 26 are fixed together by the sheath gripper 13.

As shown in FIG. 4, the sheath gripper 13 is provided at the front position of the reinforcing tube 12, and holds the outer sheath 9 and the contraction tube 26 between the double-cylindrical inner tube 27 and outer tube 28. The sheath fixing part 29 of the inner cylinder 27 is made smaller in diameter than the reinforcing cylinder 12, and the outer sheath 9 is attached to the sheath fixing part 29 so that the diameter of the outer sheath 9 is gradually reduced. A tapered portion 30 that communicates with the reinforcing tube 12
It is said that it has a structure in which it is connected. Note that the sheath fixing part 31 of the outer cylinder 28 is formed thin so that it can be plastically deformed by caulking, and the surface of the sheath fixing part 29 in the inner cylinder 27 is knurled, so that both the cylinders 27
- A sealing tape 32 is wrapped around the surface of the shrink tube 26 where it is clamped by the tubes 28. On the other hand, a plurality of O-rings 33 are provided on the outer circumference of the outer cylinder 28 to seal the space between the outer cylinder 28 and the protective pipe 20 .

Further, a pair of arms 34 are provided on the inner cylinder 27 so as to project forward in the traction direction, and a ring 35 is fixed to the tips of these arms 34 concentrically with the inner cylinder 27. A portion of the sleeve 14 that fixes the member 3 is inserted through it.

The tip of the sleeve 14 is connected to the hole 35a of the ring 35.
The ring 35 is formed with an outer diameter that can be inserted through the ring 35 with a slight gap, and a large diameter part 36 larger than the hole 35a of the ring 35 is integrally provided at the base end of the ring 35. A spherical seat 36 having a convex surface toward the tip of 14
a is formed.

Further, the extra length storage section 21 stores the extra length section 7 of the optical fiber 7.
A is wound a plurality of times and placed in one or more storage bags 37 and stored in the internal space of the protective pipe 20, and at the center position in the length direction is a bag so as to support the protective pipe 20 from the inside. An extra-length protection frame 38 is provided in contact with the inner circumferential surface of the protection pipe 20. As shown in FIG. 2, the extra length protection frame 38 includes a pair of arc-shaped support plates 39 that are curved to have approximately the same curvature as the inner peripheral surface of the protection pipe 20;
The connecting member 40 concentrically connects the support plates 39 to the protection pipe 20 with the outer peripheral surfaces of both support plates 39 facing outward. Further, the connecting member 40 is formed in a plate shape, is provided along the length direction of the protective pipe 20, and is welded to the four inner circumferential parts of the support plate 39 to connect the inner circumferential recesses. The inside of the protection pipe 20 is divided into two spaces A on the left and right.

Therefore, the extra length 7a of the optical fiber 7 is divided into halves and stored in two or more storage bags 37, and each storage bag 37 is interposed in each of the spaces A. It is. In addition, a recess 40a is formed in the center of the connecting member 40 in the connecting direction by bending it into a U-shaped cross section, and a shaft 41 through which the traction wire 16 is inserted is screwed into the recess 40a. There is.

Further, the connector storage section 22 is divided into a plurality of sections by a plurality of connector protection frames 42 provided at intervals in the length direction in the internal space of the protection pipe 20, and each section space includes a plurality of connector protection frames 42. A connector holder 43 for holding each connector 1G is provided. The connector protection frame 42 includes a plate portion 44 formed in a disk shape with a slightly smaller curvature than the inner circumferential surface of the protection pipe 20, and a cylindrical portion through which the traction wire 16 is inserted through the center of the plate portion 44. 45, and as shown in FIG. 5, a plurality of notches 46 are provided on the outer periphery of the plate-like portion 44, through which the optical fibers 7 and connectors 10 are inserted. The connector holder 43 is
It is formed into a cylindrical shape using a cushioning material such as sponge, and is provided with a plurality of through holes (not shown) to hold the connector 10 inserted into the through holes.

When the optical fiber cable 2 is to be held by the tension terminal 1 configured in this manner, the reinforcing tube 12 is inserted between the inner protector 11 and the outer sheath 9 of the optical fiber cable 2, and the reinforcing tube 12 is After attaching the support frame 23 inside, the sleeve 14 is fixed to the tension member 3 exposed from the internal protector 11, and the tip of the sleeve 14 is inserted into the hole 35a of the ring 35 of the sheath gripper 13. The outer sheath 9 is fitted onto the inner tube 27 of the sheath gripper 13 with the ring 35 and the spherical seat 36a of the large diameter portion 36 of the sleeve 14 in contact with each other. Then, when the shrink tube 26 is placed over the outer sheath 9 and the shrink tube 26 is contracted, the outer sheath 9 is brought into close contact with the reinforcing tube 12, the tapered portion 30 of the inner tube 27, and the sheath fixing portion 29, The diameter of the portion covered by the sheath fixing portion 29 is reduced. After that, sealing tape 3 is applied to the outside of the outer sheath 9.
The outer sheath 9 and the like are firmly held between the two tubes 27 and 28 by caulking the outer tube 28 with the tube 2 interposed therebetween. In addition, in addition to attaching the coupler 15, tow line 16, eyeliner 18, etc. to the sleeve 14 in a connected state, an extra length protection frame 38 is attached to the tow line 16.
, the connector protection frame 42 and the connector holder 43 are attached, and the optical fiber 7 is passed between the arms 34 of the sheath gripper 13 and guided to the extra length storage section 21, and the extra length section 7a is put into each storage bag 37. The extra length protection frame 38
When each connector 10 is held by a connector holder 43 and is then entirely covered with a protective pipe 20, the state shown in FIG. 1 is obtained.

In the state shown in FIG. 1, the tensile terminal I is in a state where the optical fiber 7 is wound around the storage bag 37 multiple times and stored in the extra length storage section 21, so that the overall length can be shortened. It is something that can be achieved. In addition, optical fiber cable 2
Since the outer sheath 9 pulled out in the distal direction from the inner protector 11 is fixed in a reduced diameter state by the sheath gripper 13, the outer diameter of the sheath gripper 13, that is, the outer diameter of the outer cylinder 28, is relatively small. It can be made smaller, and the protection pipe 20 that covers the outer cylinder 28 can also be made smaller in diameter. In this case, the protective pipe 20 has an extra length storage section 2 at an intermediate position.
It is supported from the inside by the extra length protection frame 37 of 1 and each connector protection frame 41 of the connector storage part 22, and the outer surface is maintained in a straight shape without unevenness. Further, the reinforcing tube 12 inserted between the inner protector II and the outer sheath 9 is formed thin, and unlike the sheath gripper 13, no member is provided on the outside of the outer sheath 9. Therefore, the attachment of the reinforcing tube 13 can suppress the radially outward bulge of the portion. Hence the tensile terminal! This makes it possible to reduce the overall diameter.

On the other hand, when the eye nut 18 is pulled as shown by the arrow in FIG. Large diameter part 3
6 comes into contact with the ring 35 of the sheath gripper 13 and is prevented from being pulled out, and the traction force acting on the tension member 3 is transferred from the sleeve 14 through the ring 35 to the sheath gripper 1
3, the external sheath 9 integrated with the sheath gripper 13 can be pulled while also applying a traction force. That is, these sleeve 14 and sheath gripper 1
3 is a separate part, but the large diameter part 36 and ring 3
It has the function of integrally fixing the tension member 3 and the external spring 9 by the traction force transmission action with the tension member 5.

During this pulling, the reinforcing cylinder 12 and support frame 23 inserted between the outer sheath 9 and the inner protector 11 hold the sheath gripper 13 and the inner protector 11 in the vicinity of the end of the optical fiber cable 2. When the entire tension end l is bent, such as when pulling a bent part of a conduit, the bending of the optical fiber 7 near the end of the inner protector 11 is effective. You can prevent this.

Further, in the vicinity of the sheath gripper 13, as the pulling direction of the tension member 3 changes, the sleeve 14 forms a spherical surface in the range of the gap between the tension member 3 and the hole 35a of the ring 35 of the sheath gripper 113. 1 at seat 36a
0, the tension member 3 can be bent as if swinging.

Furthermore, in the extra length storage section 21 as well, since the support plate 39 of the extra length protection frame 38 is in contact with the inner surface of the protection pipe 20, the support plate 39 absorbs external force from outside the radius of the protection pipe 20.
The surface of the protective pipe 20 can be prevented from bulging, and the extra length portion 7a can be effectively protected. Similarly,
The connector storage portion 22 is also capable of supporting external forces from radially outward by the connector protection frame 42.

In addition, in the extra length protection frame of the present invention, the number of supporting plates,
The shape of the connecting member is not limited to one embodiment, and the design can be changed as appropriate.

"Effects of the Invention" As explained above, according to the tensile terminal of the optical fiber cable according to the present invention, the following effects can be achieved.

(i) Since the extra length of the optical fiber is wound several times and stored, the total length of the tension terminal can be shortened.

(ii) Is the extra length protection frame inside the protection pipe that stores the extra length of the optical fiber? Since it is supported in this way, the mechanical strength of the extra length storage section is increased, and even if an external force in the radial direction is applied to the protective pipe during towing, the external force can be absorbed by the surface of the support plate of the full length protective frame. can be obtained, and bending of the optical fiber can be effectively prevented.

(City) The extra length protection frame is provided inside the protection pipe, and is composed of a support plate and a connecting member to ensure a space inside the protection pipe for storing the extra length. It is possible to suppress an increase in the outer diameter of the protection pipe, and to achieve a reduction in the overall diameter.

(iv) Because the extra length protection frame was provided inside the protection pipe,
The outer circumferential surface of the protection pipe can be maintained in a straight shape without unevenness, and when the pipe is towed inside the pipe, the protection pipe and the inner surface of the pipe can be uniformly contacted in the length direction, and the towing can be carried out smoothly. At the same time, it is possible to reduce local rubbing and prevent damage to the protection pipe.

[Brief explanation of the drawing]

FIG. 1 is an overall vertical cross-sectional view showing an embodiment of an optical fiber cable tension terminal according to the present invention, and FIG. 2 is a cross-sectional view of FIG.
3 is a sectional view taken along line III-Iu in FIG. 1, FIG. 4 is an enlarged view of the vicinity of the sheath gripper in FIG. 1, and FIG. 5 is a sectional view taken along line III-Iu in FIG. FIG. 6 is a cross-sectional view showing an example of an optical fiber cable, and FIG. 7 is a partially cut-away front view showing a conventional example of a tension terminal. l...Tension terminal, 2...Optical fiber cable, 3...Tensicon member, 4...Coating, 5...Spacer, 6...
Groove, 7... Optical fiber, 7a... Excess length, 8... Buffer layer, 9... Outer sheath, 10... Connector, 11... Internal protector, 12... Reinforcement cylinder, 13... Sheath gripping vessel, I4
... Sleeve, 15 ... Coupler, 16 ... Traction line, 17
...Plug, 18... Eye nut, 19... Cap,
20... Protective pipe, 21... Excess length storage section, 22... Connector storage section, 23... Support frame, 24... Support rod, 25
... Cylindrical part, 26 ... Shrink tube, 27 ... Inner cylinder, 2
8... Outer cylinder, 29... Sheath fixing part, 30... Taper part, 31... Sheath fixing part, frame, 24... Support rod, 25... Cylindrical part, 26...Shrinkable tube, 27...Inner tube, 28...Outer tube, 29...Sheath fixing part, 30...Taper one Part, 31...Sheath fixing part, 32...Sealing tape, 33...O ring, 34...Arm,
35... Ring, 35a... Hole, 36... Large diameter part, 36
a...Spherical seat, 37...Storage bag, 38...Extra length protection frame,
39... Support plate, 40... Connection member, 40a... Recessed part,
41... Mandrel, 42... Connector protection frame, ... Recess, 41... Mandrel, 42...
... Connector protection frame, 43 ... Connector holder, 44
... Plate-shaped part, 45 ... Cylindrical part, 46 ... Notch, A ... Blank space.

Claims (1)

[Claims] 1) A protective pipe (2) at the end of the optical fiber cable (2).
0) are integrally connected, and optical fiber groups (7, 7,...) are housed inside this protection pipe (20), and each of these optical fiber groups (7, 7,...) is long. The optical fibers are wound in a circle to form extra length portions (7a, 7a, . . .), and a connector (10) is attached to the terminal of each optical fiber group (7, 7, . . .). A tension terminal for an optical fiber cable, characterized in that the end of the pipe (20) is sealed with a cap (19). 2) Attach the protective pipe (2) to the end of the optical fiber cable (2).
0) are integrally connected, and optical fiber groups (7, 7,...) are housed inside this protection pipe (20), and each of these optical fiber groups (7, 7,...) is long. The optical fibers are wound in a circle to form extra length portions (7a, 7a, . . .), and a connector (10) is attached to the terminal of each optical fiber group (7, 7, . . .). The end of the pipe (20) is sealed with a cap (19), and the extra length (
An extra length protection frame (38) is provided on the outside of the protection pipe (7a, 7a,...).
A plurality of arc-shaped support plates (39) formed to have approximately the same curvature as the inner peripheral surface of the pipe (20) are fixed by a connecting member (40) concentrically with the protection pipe (20) and spaced apart from each other in the circumferential direction. A space (A) is formed between the connecting member (40) and the protective pipe (20), through which a part of the extra length part (7a) is inserted. Fiber optic cable tension terminal.