JP3229539B2 - Pooling eye for optical fiber cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pooling eye for connecting a messenger wire to a connection end of a cable, and more particularly to a pooling eye for an optical fiber cable.

[0002]

2. Description of the Related Art When an optical fiber cable 20 is pulled by a messenger wire 21 and drawn into the ground to be extended,
As shown in FIG. 3, the optical fiber cable 20 and the messenger wire 21 are connected via the optical fiber cable pooling eye 22. This is because the optical fiber cable 20 is generally vulnerable to water infiltration into the cable interior and vulnerable to elongation.
2 prevents water from entering the inside of the cable and prevents the cable from stretching.

As shown in FIG. 5, an optical fiber cable 20 is formed by twisting an optical fiber core wire 24 around an outer periphery of a tension member 23 which is a tensile strength member, covering this with a presser winding 25 which is a cushioning material, and covering the sheath ( (Sheath) 26.

A pulling eye 22 for an optical fiber cable
As shown in FIG. 4, mainly, a compression sleeve 27, a can 28, a gasket 29, a cap 30, a hex nut 31
And an eye nut 32.

[0005] The compression sleeve 27 has a cylindrical caulking portion 33.
For inserting the tension member 23 of the optical fiber cable 20 therein, and fixing the hexagonal nut 31 and the eye nut 32 to the front end of the caulking portion 33 (the right side is the front in FIG. 4). Male thread 3
4 are integrally attached. The can 28 is for covering the connection end 35 of the optical fiber cable 20 so as to cover it, and has a cylindrical shape with a narrowed front end. The eye nut 32 is for connecting the messenger wire 21.

When attaching the pulling eye 22 to the optical fiber cable 20, first, the caulking portion 33 is compressed and fixed in the radial direction with the tension member 23 of the optical fiber cable 20 inserted into the compression sleeve 27. Next, the annular gasket 29, the can 28, and the cap 5 covering the front part of the can 28 are inserted into the male screw portion 34, respectively, and attached. The hexagon nut 31 is screwed into the male screw portion 34 to insert the component. And then tighten it. Further, the eye nut 32 is attached to the male screw portion 34.
Are screwed together, and the outer periphery of the can 28 is compressed into an annular shape and tightened to prevent water from entering between the outer cover 26 and the can 28.

[0007]

However, this pulling eye 22 for an optical fiber cable has seven parts.
Since there are many individual parts, it takes time to manage the parts, the production cost of the pooling eyes 22 is high, and the work time for attaching the pooling eyes to the optical fiber cable is long. Was causing it.

[0008] Further, in mounting the pulling eye, it is necessary to disassemble and arrange all the parts having many points once and to assemble them one by one as described above. However, there is a possibility that some parts may be mistakenly forgotten to be installed or may be installed by mistake, which may cause the waterproof effect of the pooling eye to be lost or the water to enter the optical fiber cable to damage the optical fiber cable. Was.

[0009] Further, depending on an error in the assembling / attaching operation, it is considered that the pulling eye may not come out of the cable due to the tension during the cable drawing operation without exhibiting sufficient performance as the pulling eye.

[0010] Therefore, an object of the present invention is to solve the above-mentioned problems and to provide the same connection performance and waterproof performance as conventional products,
An object of the present invention is to provide a pulling eye for an optical fiber cable which has extremely good workability in mounting and has a reduced number of parts.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an optical fiber cable for holding a connection end of an optical fiber cable from which a tension member is projected in a watertight manner and connecting it to a messenger wire. The pulling eye has a can that is fitted to the jacket of the connection end and surrounds the proximal end of the tension member, and has a caulked portion that is fitted to the tension member and extends from the can. A compression sleeve, and an eye nut fixed to the extension end of the compression sleeve and connected to the messenger wire. In this way, the number of parts of the optical fiber cable pooling eye is reduced, and after inserting the optical fiber cable into the optical fiber cable pooling eye, simply crimping the can and the caulking portion, respectively, the connection end of the optical fiber cable. An optical fiber cable pooling eye is fixed to the optical fiber cable. It is preferable that at least the can and the compression sleeve are integrally formed. As a result, the optical fiber cable pulling eye is fixed to the connection end of the optical fiber cable without performing any disassembly and assembly work.

Preferably, a seal packing is provided between the can and the compression sleeve. This prevents water from entering between the can and the compression sleeve.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, a pulling eye 1 for an optical fiber cable mainly comprises a can 2 and a compression sleeve 3.
And an eye nut 4, which is used in an assembled state in advance.

The can 2 is fitted in a watertight manner on the jacket 26 of the connection end 35 of the optical fiber cable 20 to protect the connection end of the optical fiber cable 20 from external water. It is formed in a shape. The can 2 is configured such that the outer periphery thereof is crimped (tightened inward in the radial direction) to watertightly surround the jacket 26 of the connection end 35 of the optical fiber cable 20.

At the front end of the can 2 (the right side is the front in FIG. 1), a flange portion 5 is formed by bending the front end of the can 2 inward, and a compression sleeve fitted and provided inside the can 2 is provided. 3 so that water does not easily enter the fitting surface between the can 2 and the compression sleeve 3. Further, since the tension member 23 is inserted into the compression sleeve 3 as described later, the can 2 surrounds the base end (the base of the protruding tension member 23) of the tension member 23.

The compression sleeve 3 is for fixing the pulling eye 1 to the optical fiber cable 20 so as to be able to be pulled, and is formed in a cylindrical shape having a closed front end. The compression sleeve 3 is made of mild steel and has a connecting portion 6 fixedly connected to the can 2 and a caulking portion 7 fitted to the tension member 23 protruding from the connecting end 35 of the optical fiber cable 20. And a screw portion 8 for attaching the eye nut 4.

The connecting portion 6 is for connecting the compression sleeve 3 to the can 2 in a water-tight manner, and is located at the rear of the compression sleeve 3. As shown in FIGS. 1 and 2, the outer periphery of the connecting portion 6 is in close contact with the inner periphery of the can 2, and the front end of the connecting portion 6 is in close contact with the flange 5 of the can 2, and the compression sleeve 3 is locked so as not to fall forward. Further, the connection portion 6 and the can 2 are further connected to each other more firmly, and the compression sleeve 3 is connected to the can 2.
A locking portion 9 is provided to prevent the inside of the inside from moving backward. The locking portion 9 includes a male portion 10 formed on the can 2 so as to protrude radially inward, and a female portion 11 formed on the connecting portion 6 so as to be depressed inward in the radial direction. The can 2 and the compression sleeve 3 are integrated.

An O-ring 14 (seal packing) made of rubber is provided on the outer periphery of the front end of the connecting portion 6 which is in close contact with the inner periphery of the can 2, so as to prevent water from entering between the can 2 and the compression sleeve 3. Has become.

The caulking portion 7 is for caulking and fixing the tension member 23 with the tension member 23 inserted therein, and is formed integrally with the front portion of the connection portion 6. The caulking portion 7 extends from the front end of the can 2 and is provided so as to be exposed to the outside. The front end is formed so as to be closed watertight.

The screw portion 8 is formed integrally with the front end of the caulking portion 7 to form an extended end of the compression sleeve 3, and has a male screw 16 for screwing the eye nut 4 around the outer periphery. I have.

A tapered portion 15 whose diameter increases rearward is formed on the inner peripheral surface on the rear end side of the compression sleeve 3, and the tip of the tension member 23 of the optical fiber cable 20 is smoothly inserted into the compression sleeve 3. You will be guided.

The eye nut 4 is for connecting the messenger wire 21 to the pulling eye 1, and is provided at the front end of the nut portion 12 which is screwed and fixed to the screw portion 8 which is the extension end of the compression sleeve 3. The hook portion 13 for connecting the wire 21 is provided integrally. The eye nut 4 is made of steel in order to obtain a sufficient strength.

Next, the operation will be described.

Pulling eye 1 is connected to optical fiber cable 2
When the optical fiber cable 20 is attached, the jacket 26 and the optical fiber 24 are cut off so that the tension member 23 projects from the end of the optical fiber cable 20. Thereafter, the optical fiber cable 20 is inserted into the can 2 while the tension member 23 of the optical fiber cable 20 is inserted into the compression sleeve 3 as shown in FIG. At this time, since the tapered portion 15 whose diameter increases rearward is formed on the inner peripheral surface on the rear end side of the compression sleeve 3, the tension member 23 is smoothly guided into the compression sleeve 3 and inserted. Is done.

When the tension member 23 has been sufficiently inserted into the compression sleeve 3, the vicinity of the center of the caulked portion 7 of the compression sleeve 3 is swaged from the outside. By doing so, the pooling eye 1 is firmly fixed to the optical fiber cable 20, and does not come off from the optical fiber cable 20 even if the pooling eye 1 is pulled in the axial direction of the cable 20. Then, the can 2 is caulked in an annular shape so as to make at least one round from the outside. As a result, the can 2 and the jacket 26 of the optical fiber cable 20 are crimped in a watertight manner, so that water does not enter from between the can 2 and the jacket 26.

As described above, the pulling eye 1 is fitted to the jacket 26 of the connection end 35 of the optical fiber cable 20 and the can 2 surrounding the base end of the tension member 23 and the tension member 23. Compression sleeve 3 having a caulked portion 7 extended from can 2
And the eye nut 4 fixed to the extension end of the compression sleeve 3 and connected to the messenger wire 21, so that the number of parts can be reduced, the manufacturing cost can be reduced, and the assembling and attaching work can be simplified. Further, the components of the pooling eye 1 can be attached to the optical fiber cable 20 in a state where the components are assembled in advance.

Also, since the can 2 and the compression sleeve 3 are integrated, the work of attaching the pulling eye 1 can be made easy and the working time can be shortened. Pooling eye 1 always reliably and with high accuracy because there is no mounting
Can be attached to the optical fiber cable 20.

Since the O-ring 14 is provided between the can 2 and the compression sleeve 3, the can 2 and the compression sleeve 3
It is possible to reliably prevent inundation from occurring.

Further, since the engaging portion 9 is provided between the connecting portion 6 and the can 2, the connecting portion 6 and the can 2 can be firmly connected to each other, so that the compression sleeve 3 moves backward inside the can 2. Can be prevented.

Further, since the tapered portion 15 whose diameter increases rearward is formed on the inner peripheral surface on the rear end side of the compression sleeve 3,
When the pulling eye 1 is attached to the optical fiber cable 20, the tip of the tension member 23 can be smoothly guided into the compression sleeve 3, and
Can be made easier.

The material of the can 2 and the compression sleeve 3 is not limited as long as it has both watertightness and plasticity and has a necessary strength even after caulking.
May be formed of steel.

The optical fiber cable 20 in which the pooling eye 1 can be used is not limited to the structure shown in FIG. 5, but is used for all cables having a tension member 23 serving as a tensile member at the center and a jacket 26. Is also good.

[0034]

In summary, according to the present invention, the following excellent effects can be obtained.

(1) According to the configuration of the first aspect, the number of parts of the pooling eye can be reduced, and the pooling eye can be attached to the optical fiber cable in a state where it is assembled in advance.

(2) According to the configuration of the second aspect, the work of attaching the pulling eye can be facilitated.

(3) According to the configuration of the third aspect, it is possible to reliably prevent water from entering between the can and the compression sleeve.

[Brief description of the drawings]

FIG. 1 is a side view of a pulling eye for an optical fiber cable, showing a preferred embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a schematic diagram showing a drawing operation of an optical fiber cable using a pooling eye.

FIG. 4 is a side view showing a conventional pooling eye.

FIG. 5 shows a schematic structure of an optical fiber cable, V in FIG.
FIG. 5 is a sectional view taken along line -V.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pulling eye for optical fiber cables 2 Can 3 Compression sleeve 4 Eye nut 7 Caulking part 14 O-ring (seal packing) 20 Optical fiber cable 21 Messenger wire 23 Tension member 26 Jacket 25 Connection end

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshi Sato 5-1-1, Hidaka-cho, Hitachi City, Ibaraki Pref. Inside Hidaka Works, Hitachi Cable Co., Ltd. (72) Inventor Shoichi Wakuda Takada, Toshima-ku, Tokyo No. 3, 18-14, Hakusan Manufacturing Co., Ltd. (56) Reference: Japanese Utility Model 1983-115703 (JP, U) Japanese Utility Model 5-81804 (JP, U) Japanese Utility Model 63-178802 (JP, U) 63-80505 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02B 6/44 G02B 6/46 H02G 1/06

Claims (3)

(57) [Claims] 1. A pulling eye for an optical fiber cable for holding a connection end portion of an optical fiber cable having a protruded portion in a watertight manner and connecting the same to a messenger wire, wherein the tension member is fitted to a jacket of the connection end portion. And a can surrounding the base end of the tension member.
A compression sleeve fitted to the tension member and having a caulked portion extending from the can; and an eye nut fixed to an extension end of the compression sleeve and connected to the messenger wire. Pooling eye for optical fiber cable. 2. The pulling eye for an optical fiber cable according to claim 1, wherein at least the can and the compression sleeve are integrated. 3. The pulling eye for an optical fiber cable according to claim 1, wherein a seal packing is provided between the can and the compression sleeve.