JP3384891B2 - Optical fiber cable terminal structure - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber cable terminal structure.

[0002]

2. Description of the Related Art In an optical fiber cable (hereinafter referred to as "cable"), a terminal is processed into a special structure because it needs to be pulled in a duct such as a duct at the time of laying. For example, the terminal structure shown in FIG. It has been known. That is, at the end of the cable 1, the sheath (jacket) 1a is split in the longitudinal direction so as to be divided into two or four, and the cylindrical cushioning member 2 is arranged between the sheath 1a and the exposed inner portion, and An elastic sealing material or a waterproof tape 3 is wound around the outer side of 1a for waterproofing, and then a gripping metal fitting 4 which is screwed to a buffer member 2 at a right portion (not shown) is attached to the outside of the gripping metal fitting 4 By reducing the diameter of the cushioning member 2, the sheath 1a and the waterproof tape 3 at the overlapping portion,
This is a structure for gripping the end portion of the sheath 1a.

Here, at the end of the cable 1, as shown in FIG. 13, the tension member 1b and the traction line 6 of the cable 1 are fixed via a fixing member 5 bolted to the end of the holding member 4. The grip 7 is attached. The grip 7 is designed to be prevented from coming off from the fixing 5 by a flange 7a provided at the left end. And cable 1
The terminal is protected by a protective hose 8 and a rear end component 9 attached to the cable 1 in advance. Some of the rear end parts 9 provided with slits may be attached last.

An extra length is processed in the protective hose 8,
A plurality of optical fibers of the cable 1 having an optical connector attached to the tip, a protective member for protecting the inside from an external lateral pressure that acts, and the like are housed, and the right end of the protective hose 8 is pulled by a pulling means. A member (not shown) is attached.

[0005]

By the way, in the above-mentioned terminal structure, it is necessary to tear the sheath in the longitudinal direction because the cushioning member is arranged between the sheath and the inner portion of the cable, and the sheath is wound outside the sheath. Since waterproof measures are taken by the rotating waterproof tape, the number of steps for processing the terminal is large, and the optical fiber core may be damaged when the sheath is torn.

Further, since the cable is laid around the inside of the pipe and installed, it is desired to suppress the increase in outer diameter as much as possible. However, in the above-mentioned terminal structure, there is a problem that the outer diameter is excessively increased because the waterproof tape is wound in addition to attaching the cushioning member and the gripping cylinder to the end portion of the cable. Further, the terminal structure of the cable described above can sufficiently withstand the pulling force acting through the pulling wire 6 and the tension member 1b. However, since the gripping metal fitting is only prevented from coming off from the fixing metal fitting by the left end flange, it is against the pushing force acting from the cable to the terminal side, that is, the pushing force acting through the cable sheath in the terminal direction. There is no resistance. Therefore, in the above-mentioned terminal structure, when the pushing force acts from the cable side, the tension member is loosened. Therefore, after pulling the cable, there is a problem that the tension member must be newly gripped when connecting with another cable.

The present invention has been made in view of the above points, and has a terminal structure of an optical fiber cable in which the number of processing steps is small, there is no fear of damaging the optical fiber core wire, and an excessive increase in outer diameter is suppressed. The primary purpose is to provide. A second object of the present invention is to provide a terminal structure of an optical fiber cable having a high resistance to both pulling and pushing directions.

[0008]

In the present invention, in order to achieve the above object , the ends of an optical fiber cable whose outer periphery is covered with a sheath are formed in a U-shape and are opposed to each other.
Have a chewing Komu protrusions on the sheath half inside, and the distal end side
A gripping member whose both edges are cut out to form a stepped portion, and an inner diameter of the gripping member is smaller than an outer diameter of the narrowing portion.
Is slightly smaller, and has a length that can be accommodated in the step,
It is configured such that a cylindrical regulating member that is fitted onto the narrow portions on both sides to regulate the expansion is attached.

[0009] good Mashiku, the gripping member, a member for gripping the tensile strength member of the optical fiber cable is arranged adjacent to the terminal side of the tensile strength member, and, connecting this member.

[0010]

The gripping member grips the sheath of the optical fiber cable. The cylindrical regulation member regulates the diameter expansion of the grasping member that grasps the sheath, and maintains the grasped state of the sheath by the grasping member. At this time, make sure that the inner diameter of the restriction member is
Gripping by making the diameter slightly smaller than the outer diameter of the narrow part
The elastic force acts on the regulating member when it is fitted onto the narrow portion of the member, and both ends are regulated by the stepped portion, so that it does not come off from the gripping member .

Further, the holding member has a holding metal fitting for holding the tensile strength member of the optical fiber cable, which is arranged adjacent to the terminal side of the tensile strength member, and when the both members are connected and integrated, a tensile force acting on the terminal or The amount of elongation of the tensile strength material and the sheath can be made equal to the pushing force. In addition, handling of the tensile strength material becomes easy when assembling the terminal structure .

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment relating to the terminal structure of an optical fiber cable of the present invention (hereinafter, simply referred to as "terminal structure") will be described in detail below with reference to FIGS. Here, in the following examples including the present example, the cables will be described using the same reference numerals as those of the cable 1 described in the above-mentioned related art, but the cable 1 is mainly arranged as shown in FIG. A polyethylene rod 1d having a plurality of slots 1c formed in the longitudinal direction is arranged on the outer side of the arranged tension member 1b, and the outer side is covered with a sheath 1a. Further, in each slot 1c, a plurality of tape fibers 1e formed by molding a plurality of optical fibers in a tape shape are stacked and accommodated.

Although not shown in the accompanying drawings, the cable 1 usually has a layer of a presser winding (not shown) formed on the outer periphery of the polyethylene rod 1d. Here, in the terminal structure 10 of the present embodiment, as shown in FIG. 1, the grasping metal fitting 11 and the restriction member 12 are attached to the end portion of the cable 1. As shown in FIG. 2, the grip fitting 11 is a U-shaped member having two grip arms 11a and a bridge portion 11b connecting the arms 11a and 11a. Each gripping arm 11a has a stepped portion 11c whose width is narrowed on the tip side.
Is formed, and a plurality of triangular protrusions 11d are provided on the inner front half side. Further, the bridge portion 11b has an opening 11e formed at the center.

Here, the holding metal fitting 11 is the holding arm 11
By bending the tips of a and 11a,
The diameter of the circumscribed circle determined by c and 11c can be reduced. At this time, the grasping metal fitting 11 has the regulating member 12
The diameter of the circumscribed circle before the arrangement of the
The length of the bridge portion 11b is determined so as to be larger than the inner diameter of the bridge portion 11b.

The restriction member 12 is a cylindrical member shown in FIG. 3, and is positioned on the stepped portion 11c of each gripping arm 11a to restrict the gripping arms 11a and 11a from expanding. Therefore, the regulating member 12 has an inner diameter of the gripping arm 11.
The diameter of the circumscribed circle determined by the stepped portions 11c and 11c of a and 11a is slightly smaller than that of the circumscribed circle, and the length that can be accommodated in the stepped portion 11c is used.

The gripping member 11 pulls out the tension member 1b extending from the end of the cable 1 from the opening 11e, and hooks the holding member 13 attached to the tension member 1b on the bridge portion 11b at the opening 11e. . Next, the distal end side of each gripping arm 11a is pressed down, and the plurality of protrusions 11d are made to bite into the sheath 1a of the cable 1.

Next, while maintaining this state, the end portion of the gripping metal fitting 11 is covered with the regulating member 12 to form the stepped portions 11c, 1c.
Move to 1c. Then, the regulating member 12 has the step portion 1
It is positioned by 1c and 11c and attached to the grip fitting 11. As a result, as shown in FIG. 4, the gripping metal 11 grips the cable 1 by the plurality of protrusions 11d provided on each gripping arm 11a biting into the sheath 1a, and the elastic force acting from each gripping arm 11a. The regulating member 12 does not move from the stepped portions 11c and 11c, and the grasping state of the sheath 1a is maintained by the regulating member 12.

Therefore, in the terminal structure 10 of this embodiment, since the sheath 1a is not torn, the tape fiber 1e is not damaged and it is not necessary to carry out waterproofing with a waterproof tape or the like. Therefore, in the terminal structure 10, the first object of the present invention is achieved, in which the number of processes is reduced, the workability in the terminal process is improved, and the increase in the outer diameter due to the waterproof treatment is suppressed.

Next, a second embodiment of the present invention will be described in detail with reference to FIGS. Terminal structure 20 of the present embodiment
As shown in FIG. 5, the holding metal fitting 2 is attached to the end of the cable 1.
1, the restriction member 22 and the holding metal fitting 23 are attached, and these are covered by the outer sleeve 24 and the rear end component 25. The grip 21 is the sheath 1a of the cable 1.
6 is a substantially cylindrical metal fitting that elastically grips
Further, as shown in FIG. 7, a slit 21b is formed in the main body 21a, and a plurality of triangular protrusions 21c protruding in the radial direction are provided in the circumferential direction on the inner surface of the main body 21a. Here, the grip fitting 21 elastically deforms due to the provision of the slits 21b, and the diameter is reduced to the extent that the restriction member 22 can be arranged on the outside, but at this time, in the state before the restriction member 22 is arranged on the outside, the outside The diameter is formed to be larger than the inner diameter of the restriction portion 22b, and the height of the protrusion 21c is set to be slightly lower than the thickness of the sheath 1a.

The restriction member 22 restricts the diameter of the grip fitting 21 and is arranged outside the grip fitting 21, as shown in FIG. The restricting member 22 has a flange 22a protruding outward in the radial direction at one end of a cylindrical member, and the restricting portion 22b on the other end side is formed to have a slightly larger inner diameter than the flange 22a side. Further, the regulation member 22 is
The tapered small diameter portion 22c is formed on the inner surface of the flange 22a side.
A concave groove 22d is formed in the circumferential direction of the outer surface. Further, the restriction portion 22b has a screw hole 22e.
And a plurality of openings 22f are formed.

The holding metal fitting 23 is the restriction portion 2 of the restriction member 22.
Attached to 2b, tension member 1b of cable 1
A cylindrical member that holds the end of the
A large-diameter portion 23a is formed on the side of the regulating portion 22b at one end, a small-diameter portion 23b is formed on the other end, and a flange 23c having a thin wall is provided on the large-diameter portion 23a side. Holding bracket 23
Abuts the tip of the flange 23c against the holding metal fitting 21,
It is connected to the restriction portion 22b of the restriction member 22 by a bolt 26 screwed through the opening 22f of the restriction member 22.

The outer sleeve 24 is a cover for covering the above-mentioned members 21 to 23 together with the rear end part 25, and a flange 24b protruding inward in the radial direction is integrally formed with one end of a cylindrical main body 24a having a thick wall. Has been formed. Rear part 25
Is a flange 25a on the flange 22a side of the regulating member 22.
Is a cylindrical member having a flange 25a, and is connected to the main body 24a of the outer sleeve 24 by a plurality of bolts 27 at the flange 25a via the flange 22a of the regulating member 22.
In addition, it is convenient that the rear end part 25 is provided with a slit so that it can be easily removed after laying the cable or divided into two.

At the time of connection, as shown in FIG. 5, a seal ring 28 having a wedge-shaped cross section and elasticity is arranged on the tapered small-diameter portion 22c formed on the restriction member 22, and the cable 1 and the restriction member are arranged. The gap formed between 22 and the rear end component 25 is sealed. The terminal structure 20 of this embodiment is configured as described above, and is assembled into the terminal of the cable 1 as follows.

In the cable 1, the terminal is processed in advance to cut the sheath 1a to expose the polyethylene rod 1d and the tension member 1b by a predetermined length, and the rear end part 25, the seal ring 28 and the regulating member 22 are provided on the terminal side. Insert them in this order. If the rear end component 25 is provided with a slit or is divided into two parts, it is not necessary to fit them in advance.

Next, the holding metal fitting 2 is placed at a desired position of the cable 1.
1 is arranged, and the outer side is pressed in the radial direction to reduce the diameter to cause the plurality of protrusions 21c to bite into the sheath 1a, and at the same time, as shown by the arrow in FIG. The grip metal fitting 21 is arranged inside the.
A cross-sectional view of this state is shown in FIG.
Since the height of the protrusion 21c is set slightly lower than the thickness of the sheath 1a, the tape fiber 1e is not damaged. Further, the grip 21 is elastically contracted by the slit 21b formed in the main body 21a,
The restriction member 22 is arranged outside. For this reason, the gripping metal fitting 21 does not easily come off from the restriction member 22 due to the elastic force acting on the restriction member 22.

Next, a screw 29 is attached to the screw hole 22e, and the holding metal fitting 21 is pushed inward in the radial direction to maintain the diameter reduced state. In parallel with this work or after mounting the screw 29, the holding metal fitting 23 is fitted from the tip side of the cable 1 and the tip of the flange 23c is abutted against the grip metal fitting 21,
The holding metal fitting 23 is connected to the restriction portion 22b of the restriction member 22 by a bolt 26 attached from the opening 22f. As a result, the holding metal fitting 23 is fixed to the regulation member 22.

Further, as shown in FIG. 5, the tension member 1b holds the holding metal fitting 2 by caulking the small diameter portion 23b while being pulled out from the small diameter portion 23b of the holding metal fitting 23.
3 is gripped. After that, the seal ring 28 and the rear end component 25 are moved to the regulating member 22 side, and the seal ring 28
Is arranged in the small diameter portion 22c, and the flange 25a of the rear end component 25 is abutted against the flange 22a of the regulating member 22. As a result, in the terminal structure 20, the seal ring 28 seals between the cable 1 and the restriction member 22 so that water or the like does not enter.

Next, the seal groove 22d of the regulating member 22 is filled with O.
The ring 22g is attached, and the outer sleeve 24 is fitted into the restriction member 22 and the holding metal fitting 23 from the tip side of the cable 1. Then, the end portion of the main body 24a is abutted against the flange 22a of the regulating member 22, and the rear end part 25 is fixed by the bolt 27.
Connect with. As a result, in the cable 1, the members 21 to 23 attached to the ends are the outer sleeve 24 and the rear end component 2.
While being covered with 5, the O-ring 22g similarly seals between the restriction member 22 and the outer sleeve 24.

Incidentally, in addition to the above-mentioned grip fitting 21, FIG.
It is also possible to use a split metal fitting 21 as shown in FIG. In the case of this grip fitting 21, the outer diameter thereof is larger than the inner diameter of the restriction member 22 before gripping the sheath 1a. Then, when the sheath 1a is gripped, the grip fitting 21 is protruded into the sheath 1a and the upper and lower gaps of the split grip fitting 21.
The outer diameter of the c is reduced by the amount of c, and the reduced diameter state is maintained by the restricting member 22 and the screw 29.

As described above, also in the terminal structure 20 of the present embodiment, since the sheath 1a of the cable 1 is not torn, the tape fiber 1e is not damaged and it is not necessary to carry out waterproofing with a waterproof tape or the like. Therefore, in the terminal structure 20, the first object of the present invention is achieved in which not only the number of processes is reduced and the workability in the terminal process is improved, but also the increase in the outer diameter due to the waterproof treatment is suppressed.

In the terminal structure 20, for example, as shown in FIG. 9, an optical connector 1f is attached to the tip of the extra length portion of each tape fiber 1e extending from the end of the cable 1, and the extra length portion is covered with a vinyl bag. 29, 30
Then, after the extra length processing, the extra length portions are collectively put in the vinyl bag 31. Next, the plastic bag 31
The extra length portion accommodated in (1) is accommodated in the metal corrugated pipe 33 having the holding member 32 attached to one end. The other end of the metal corrugated pipe 33 is connected to the right end of the outer sleeve 24 in advance by screwing, welding, or the like and serves as a pulling end. At this time, the metal corrugated tube 33 has the outer sleeve 24 and the hold member 32.
The ring members 34, 34 are attached to the respective connecting portions with the outer sleeve 2 through the ring members 34.
4 and the holding member 32 are integrated by welding.

Then, the cable 1 having the terminal structure 20.
When pulling in ducts such as ducts for laying,
The holding member 32 is held by the holding means and pulled. At this time, in the terminal structure 20 of the cable 1, the traction force is transmitted to the cable 1 via the hold member 32, the metal corrugated pipe 33, the outer sleeve 24, the restricting member 22, the grip fitting 21, and the holding fitting 23. In addition, the terminal structure 20
When a pushing force acts from the cable 1 side, the pushing force is transmitted to the holding member 32 through a path opposite to the above, the tension member 1b does not loosen, and the tension member 1b is not pulled in any direction. The above-mentioned second object of the present invention of exhibiting high resistance is achieved.

Further, a third embodiment of the present invention, in which the diameter is further reduced as compared with the terminal structure 20 according to the second embodiment, will be described in detail with reference to FIGS. 10 and 11. As shown in FIG. 10, in the terminal structure 40 of this embodiment, a grip fitting 41, a restricting member 42, and a holding fitting 43 are attached to the end of the cable 1, which are an outer sleeve 44 and a rear end component 45.
It is covered by and.

Here, in the terminal structure 40, the restriction member 42 and the rear end component 45 have no flange, the outer sleeve 44 is attached to the restriction member 42 by the bolt 50, and the seal ring 48 is the pressing ring. 51
With the exception of being held by the small-diameter portion 42c of the restriction member 42 by means of, the structure is substantially the same as each component of the terminal structure 20.

Therefore, the components corresponding to the components of the terminal structure 20 are denoted by the corresponding reference numerals including the details in the accompanying drawings, and the detailed description will be omitted. Here, as shown in FIG. 11, the restriction member 42 includes the small-diameter portion 4
A female screw portion 42h is formed on the inner surface on the outer end side adjacent to 2c. Further, the pressing ring 51 is attached to the female screw portion 42h by the male screw portion 51a formed on the outer periphery,
It is fixed to the female screw portion 42h by a fixing screw.

The terminal structure 40 of this embodiment is subjected to terminal treatment in advance, and the rear end component 45, the pressing ring 51, the seal ring 48, and the regulating member 42 are fitted to the terminal side in this order. It is assembled as follows. First, similarly to the second embodiment, the grip metal fitting 41 is attached to a desired position of the cable 1, the grip metal fitting 41 is arranged inside the restricting portion 42b, and the screw 49 is attached to the screw hole 42e to attach the grip metal fitting 41. Is held in a reduced diameter state.

In parallel with this work or after mounting the screw 49, the holding metal fitting 43 is fitted from the tip side of the cable 1,
The tension member 1b of the cable 1 is pulled out forward from the small diameter portion 43b, and in this state, the holding metal fitting 43 is fixed to the tension member 1b by caulking or the like. And the flange 4
The tip of 3c is abutted against the holding metal fitting 41, and the holding metal fitting 43 is connected to the restriction portion 42b of the restriction member 42 by the bolt 46 attached from the opening 42f. As a result, the holding metal fitting 43 is fixed to the regulating member 42.

After that, the seal ring 48 and the pressing ring 51 are moved to the regulating member 42 side, the seal ring 48 is arranged in the small diameter portion 42c, and then the pressing ring 51 is attached to the female screw portion 42h and fixed by the fixing screw 52. . As a result, in the terminal structure 40, the seal ring 48 seals between the cable 1 and the restriction member 42 so that water or the like does not enter.

Next, the rear end component 45 is moved to the regulating member 42 side and abutted against the end portion of the regulating member 42. Next, an O-ring 42g is attached to the seal groove 42d of the regulating member 42, the outer sleeve 44 is fitted into the regulating member 42 and the holding metal fitting 43 from the tip side of the cable 1, and the main body 44a is fixed to the regulating member 42 with a plurality of bolts 50. . This allows
The cable 1 is sealed between the restriction member 42 and the outer sleeve 44, and the members 41 to 4 attached to the terminals.
3 is covered by the outer sleeve 44 and the rear end piece 45.

As described above, also in the terminal structure 40 of this embodiment, since the sheath 1a of the cable 1 is not torn, the tape fiber 1e is not damaged and it is not necessary to carry out waterproofing with a waterproof tape or the like. Therefore, in the terminal structure 40, the first object of the present invention is achieved in which not only the number of processes is reduced and the workability in the terminal process is improved, but also the increase in the outer diameter due to the waterproof treatment is suppressed.

Moreover, in the terminal structure 40 of this embodiment, the pulling force acting on the outer sleeve 44 along with the pulling is transmitted to the cable 1 via the restricting member 42, the grip fitting 41 and the holding fitting 43, and The pushing force acting from the cable 1 is transmitted to the outer sleeve 44 through the opposite route, and does not loosen the tension member 1b. Therefore, also in the terminal structure 40 of the present embodiment, the second object of the present invention that high resistance is exerted in both the pulling and pushing directions can be achieved.

[0042]

As is apparent from the above description, according to the present invention, the number of processing steps is small, there is no fear of damaging the optical fiber core wire, and the optical fiber cable which suppresses an excessive increase in outer diameter is provided. A terminal structure is provided. Moreover, since the gripping member is formed such that the outer diameter thereof is larger than the inner diameter of the regulating member in the state before the cylindrical regulating member is externally fitted , the gripping member is elastically fitted when the regulating member is externally fitted. The force acts on the regulating member and does not easily come off the regulating member.

Further, since the member for holding the tensile strength member of the optical fiber cable is arranged adjacent to the terminal side of the tensile strength member and is connected to this member, the holding member is assembled at the time of assembling the terminal structure. Easy handling of the tensile strength material .

[Brief description of drawings]

FIG. 1 is a front view showing a first embodiment of the terminal structure of an optical fiber cable according to the present invention.

FIG. 2 is a perspective view of a holding member used in the terminal structure of FIG.

FIG. 3 is a perspective view of a regulating member used in the terminal structure of FIG.

4 is a cross-sectional view of the terminal structure of FIG. 1 taken along line IV-IV.

FIG. 5 is a front view showing a second embodiment relating to the terminal structure of the optical fiber cable of the present invention and having an upper half side of the terminal structure as a cross section.

6 is a side view of a holding member used in the terminal structure of FIG.

FIG. 7 is a perspective view showing an arrangement of a holding member and a restricting member attached to the end of the optical fiber cable.

8 is a sectional view taken along the line VIII-VIII of FIG.

9 is a front view showing an example of a state in which the terminal structure shown in FIG. 5 is processed into a towing end.

FIG. 10 is a front view showing a third embodiment relating to the terminal structure of the optical fiber cable of the present invention and showing the upper half side of the terminal structure in section.

11 is a seal ring used in the terminal structure of FIG.
It is a front view which made the upper half the cross section the principal part of a presser ring and a regulation member.

FIG. 12 is a half sectional view showing a terminal structure of a conventional optical fiber cable.

13 is a front view showing the main part of the terminal structure shown in FIG. 12 processed into a towing end.

[Explanation of symbols]

1 optical fiber cable 1a sheath 1b Tension member (tensile strength material) 10 terminal structure 11 Grip 12 Control member 20 terminal structure 21 grip 22 Control member 23 Holding bracket 24 Outer sleeve (first cover) 25 Rear end parts (second cover) 40 terminal structure 41 grip 42 Control member 43 Holding bracket 44 Outer sleeve (first cover) 45 Rear part (second cover)

Front page continued (72) Inventor Etsuo Tanabe 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (72) Shinji Nagasawa 1-1-6 Uchisaiwai-cho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Incorporated (72) Inventor Mikio Tsutsumi 1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Within Nippon Telegraph and Telephone Corporation (56) Reference JP-A-7-218791 (JP, A) Mitsuihei 5-90405 (JP, U) S. 35-10972 (JP, Y1) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02B 6/46 G02B 6/44

Claims (2)

(57) [Claims] To 1. A fiber optic cable coated with a sheath outer peripheral terminal, without a U-shaped, have a protrusion biting into the sheath on both sides the first half interior facing, and cut the edges of the distal end Missing
And a gripping member that is a narrow portion that forms a step, and the inner diameter is slightly smaller than the outer diameter of the gripping member in the narrow portion.
It is small and has a length that fits in the stepped portion, and both side portions
A terminal structure for an optical fiber cable, characterized in that a cylindrical regulating member that is fitted onto the narrow portion of the casing and regulates expansion is attached. Wherein said gripping member, member for gripping the tensile strength member of the optical fiber cable is disposed adjacent to the terminal side of the tensile strength member, and is coupled with the member, according to claim 1 fiber optic cable Terminal structure.