JP2789092B2 - Optical fiber cable branch structure - Google Patents

Description

The present invention relates to a branch structure of an optical fiber cable. [Prior art and its problems] Generally, when an optical fiber core or an optical fiber unit of an optical fiber cable having a plurality of optical fiber cores or optical fiber units in a sheath is branched, After exposing the optical fiber core or the optical fiber unit from the sheath and taking out the branch fiber of the optical fiber core or the optical fiber unit, the sheath was sealed from the outside. However, since the cable is usually wired close to a wall or the like, it is extremely difficult to seal the cable, and there is a possibility that the branch fiber may be damaged. Accordingly, an object of the present invention is to provide a branch structure of an optical fiber cable that can easily and quickly branch a branch fiber of an optical fiber cable and that does not damage the branch fiber. [Means for Solving the Problems] The optical fiber cable branch structure of the present invention comprises an optical fiber cable of an optical fiber cable having a plurality of optical fiber cores or optical fiber units in a sheath. A branch structure for branching a wire or an optical fiber unit to outside the sheath; and covering an optical fiber core or an optical fiber unit exposed from a coated end of the sheath at a predetermined portion of the cable. Having a branch pipe for guiding the optical fiber core or the branch fiber of the optical fiber unit to the outside, and in which the base end of the branch fiber protection pipe is inserted into the branch pipe, A case body consisting of a pair of half bodies that can be fitted; removably fitted into a branch groove of the half body of the case body, and fitted into a concave groove and the concave groove in a branch pipe portion of the case body; From the convex part The branch fiber protection tube is inserted through the retaining fiber mechanism, and has an insertion hole through which the branch fiber is inserted, and the distal end is inserted and fixed to the base end of the branch fiber protection tube. And a connector attached to the case body. [Operation] With the configuration described above, since the branch fiber protection tube through which the branch fiber branched from the cable is inserted is attached via the connecting member, the branch fiber is always protected. Since it is housed inside the opening end of the case main body via the retaining mechanism, it does not fall out of the case main body. In addition, the case body is composed of a pair of half bodies that can be expanded or divided, and furthermore, since the connecting tool is detachable from the branch groove of the half body, the mounting of the protective tube to the case body is performed by the case. The half body of the main body is set to the expanded or divided state, and in that state, the connecting tool whose tip is inserted and fixed in the protective tube is fitted into one of the branch grooves of the half body, and thereafter, a pair of The halves may be overlaid and the halves may be integrated. EXAMPLES Hereinafter, the present invention will be described in detail with reference to the drawings showing examples. 2, 5, and 6, reference numeral 1 denotes an optical fiber unit 3 of an optical fiber cable 4 having a plurality of optical fiber units 3 in a sheath 2. A case main body 5 having a branch pipe section 10 for guiding a branch fiber F of an optical fiber unit 3 to the outside, and a protective tube 36 through which the branch fiber is inserted, which is an optical fiber cable branch section structure for branching. And a connector 35 for attaching to the branch pipe section 10 of the main body 5. Thus, the case body 5 is formed of a cylindrical body whose both ends 6, 7 are each reduced in diameter, and is provided with the branch pipe portion 10 protruding in a direction perpendicular to the axial direction at the center thereof. Also,
Recessed circumferential grooves 11 and 12 are formed in the ends 6 and 7, respectively, and tips of the ends 6 and 7 are formed in tapered tapered surfaces 13 and 14, respectively. Specifically, as shown in FIG. 2, the case main body 5 includes a main body groove 15 having a substantially semicircular cross section, and a branch groove 16 having a substantially semicircular cross section continuously provided from the main body groove 15. , And can be divided. In addition, the branch groove 16 has a so-called Mt.
An outer flange 17 is formed at an opening edge except for both ends of the main body groove 15 and a front end of the branch groove 16, and a rear surface 17 a of the outer flange 17 to both ends of the main body groove 15 and a front end of the branch groove 16. Open end faces 18,19,
20 is a mating surface 21. And this half-body 5a, 5
A packing 22 made of rubber or synthetic resin is interposed between the mating surfaces 21 and 21 of a, and the half-pieces 5a and 5a are joined together, and the half-pieces 5a are applied to the surface 17b of the outer flange 17 of one half-piece 5a. A plate 25 is applied, and a fixing tool 23 such as a screw is inserted into a through hole 24 provided through the outer flange 17, so that the half bodies 5a, 5a are fixed to each other to be integrated. Then, the branch pipe portion 10 is formed by the superposed branch grooves 16,16. In this embodiment, the fixing tool 23 uses a screw 23a and a nut 23b, and the nut 23b is embedded in the through hole 24 of the other half 5a. Next, as shown in FIG. 1, the connecting member 35 is housed in the opening end 52 of the branch pipe section 10 via a retaining mechanism N, and has an insertion hole 53 through which the branch fiber F is inserted. The distal end portion 54 is inserted into the base end portion 55 of the branch fiber protection tube 36 to attach the branch fiber protection tube 36 to the case main body 5. That is, the coupling tool 35 is formed of a cylindrical body having an outer flange-shaped convex portion 34 at the base end, and the convex portion 34 fits into a concave groove 57 formed on the inner peripheral surface 56 of the open end of the branch pipe portion 10. And the branch pipe section 10
It is provided so that it does not fall out from the opening end 52 of the opening.
That is, in this case, the concave-convex portions 57 and 34 constitute a retaining mechanism. Further, a seal ring 58 such as an O-ring is attached to the projection 34. As shown in FIG. 7, the protective tube 36 is made of a metal flexible tube (that is, a metal spiral tube). When the tube is pulled in the longitudinal direction, the inner diameter D is reduced. D expands. That is, the protective tube 36 has one end bent in the inner diameter direction and the distal end folded in the axial direction to form a hook-shaped fitting portion 62, and the other end is bent in the outer diameter direction. At the same time, it is formed by combining a short tube 64 having a hook-shaped fitting portion 63 formed by folding the distal end side in the axial direction. Therefore, if the protection tube 36 in a contracted state is inserted into the distal end portion of the connector 36 and then the protection tube 36 is pulled, the inner diameter D of the protection tube 36 is reduced, and the protection tube 36 is Fixed to 35. It is preferable that the protective tube 36 is further covered with a coating layer made of a synthetic resin having flexibility. In addition, through-holes 28 through which the sheath ends 2a of the sheaths 2 of the cable 5 are removably inserted into both ends of the case body 5.
, Each of which has a cap. That is, as shown in FIG. 3, the cap 8 has concave peripheral grooves 11 and 12 formed on the end portions 6 and 7 of the case main body 5 on the outer peripheral surface 26 and a tapered surface.
A concave peripheral groove 50 and a tapered surface 29 corresponding to 13 and 14 are formed, and a tapered surface 30 is further formed on the base end side. In the present embodiment, the cap 8 is
The sheath 2 is formed so that the sheath 2 can be easily inserted into the insertion hole 26. In this case, it is also preferable that the cap 8 is not a pair of half-pieces 8a, 8a but an integral one having a slit formed so as to expand the insertion hole 28. Further, when forming this slit portion, it is preferable that the slit portion is formed in a linear shape or a bias shape. Then, the coated ends 2a, 2a of the sheath 2 of the optical fiber cable 4 are inserted into the caps 8, 8 configured as described above, and the caps 8, 8 are respectively inserted into the ends 6, 7 of the case body 5. The half-pieces 5a, 5a are put together so that the
a, 5a are integrated as described above, and the tightening bands 9, 9 are fitted in the concave circumferential grooves 11, 12 of the case body 5, respectively, and the tightening bands 9, 9 are tightened. In the portions 6 and 7, the inner peripheral surface 27 of the case body 5 and the outer peripheral surface 26 of the cap 8, and the inner peripheral surface 32 of the cap 8 and the outer peripheral surface 33 of the sheath end 2a of the sheath 2 are in close contact with each other. The case main body 5 is attached to the cable 4 so as to cover the optical fiber units 3 exposed from the covering ends 2a of the sheath 2 at predetermined portions (branch portions) of the cable 4. In this case, the branch pipe section 10
A connector 35 having a protection tube 36 inserted and fixed at the distal end thereof is provided at the open end of the connector 35. The branch fiber F is inserted through the protection tube 36 through the insertion hole 53 of the connection tool 35. The optical fiber unit 3 used in the embodiment is
As shown in FIG. 4, a coating layer 39, a tension member 40 contained in the coating layer 39, and six optical fiber cores 48 are provided.
And consisting of In this case, of course, the number of optical fiber cores 48 is free. Thus, the branch structure 1 configured as described above is
For example, as shown in FIGS. 9 and 10, the optical fiber unit 3 of the cables 4... Wired on the frame 38 attached to the wall surface 37 is used for branching. That is, in this case,
Although the dimension A between the wall surface 37 and the cable 4 is extremely small, if this structure 1 is used, as described above, it can be easily attached, and even if the dimension A is small, it does not matter. . FIG. 8 sequentially shows a method of branching the optical fiber unit 3 when the branch structure 1 is used.
As shown in FIG. 8I, at predetermined positions, the optical fiber units 3 are exposed from the sheath 2 by a predetermined size.
As shown in FIG. 8 (II), a predetermined dimension is exposed at a part separated from the predetermined part. And then, FIG.
As shown in III, the optical fiber unit 3 to be branched is cut at the separated portion, the unit 3 is pulled out from the predetermined portion, and in this state, the branch portion structure 1 is attached to the predetermined portion, and Branch pipe part to the case body 41
The structure 42 having the same structure as that of the branch structure 1 except that the branch structure is not provided is attached, and the branching operation is completed. Thus, according to the embodiment described above, the sheath end of the sheath 2
Caps with 2a and 2a inserted through the insertion holes 28 can be easily installed at both ends 6 and 7 of the case body 5, respectively, and the optical fiber unit 3 can be inserted into the branch pipe section 10. When the tightening band 9 is tightened, the both ends 6, 7 of the case body 5 are completely sealed, so that the branching operation becomes extremely simple.
The branch structure 1 is excellent in drip-proof or waterproof. Further, since the base end of the branch groove 16 is curved, the optical fiber unit 3 guided from the branch pipe portion 10 to the outside of the case body 5 is not sharply bent. The unit 3 is not damaged. The radius of curvature of the curved portion 51 is set to be equal to or larger than the allowable bending radius of the unit 3 so that the unit 3 does not bend beyond the allowable bending radius. Also, ends 6,7
Since the recessed grooves 11 and 12 are formed in the end portions, the tightening bands 9 and 9 do not come off from the end portions 6 and 7, and furthermore, the caps 8 and 8
Since the outer peripheral surface 26 and the inner peripheral surface 27 of the end portions 6 and 7 have corresponding uneven shapes, the caps 8 and 8 do not come off from the case body 5 in a tightened state. . Then, as shown in FIG.
Using the connecting tool 35 not provided with 58, the outer peripheral surface of the open end 52 of the branch pipe portion 10 or the outer peripheral surface of the base end 55 of the protective tube 36 exposed from the open end 52, PVC tape, A seal ring tape 61 such as butyl rubber tape is wound around the branch pipe portion 10.
It is also preferable to seal from the open end 52 to the base end of the protective tube 36. FIG. 12 shows another embodiment of the retaining mechanism N. In this case, the retaining mechanism N includes a concave groove 59 formed at the base end of the connecting tool 35 and a branch pipe of the case body 5. A convex portion 60 is formed on the inner peripheral surface 56 of the opening end of the portion 10 and fits into the concave groove 59. Next, FIG. 13 shows another embodiment of the case main body 5. In this case, the case main body 5 is not splittable but expandable. That is, the corresponding outer flanges 17, 17 of the half bodies 5a, 5a are connected to each other to form a hinge portion 43. Also,
A concave groove 44 is formed on one of the hinge portions 43 and a convex portion is formed on the other.
The projection 45 is fitted into the concave groove 44 in a state where the half bodies 5a are fitted together as shown in the figure. Therefore, the case main body 5 can be developed as indicated by arrows X and Y, and the sheath ends 2a and 2a of the sheath 2 can be easily attached to both ends 6 and 7 of the case main body in the same manner as in the above-described embodiment. The caps 8, 8 in a state in which is inserted through the insertion hole 28 can be easily installed. If this case body 5 is used, the hinge
Since there is no need to fix the fixing member 23 as in the above embodiment to the 43, as shown in FIGS. 9 and 10, when the dimension A between the wall surface 37 and the cable 4 is extremely small, it is particularly optimal. It becomes something. In addition, the present invention is not limited to the illustrated embodiment, and the design can be freely changed without departing from the gist of the present invention.
In FIGS. 1 and 12, a seal ring tape 61 is preferably wound around the open end 52 of the branch pipe portion 10 to the base end of the protective tube 36, as shown in FIG. In the figure, it is also preferable to interpose a seal ring 58 between the convex portion 60 and the concave groove 59. It is also preferable that the ends 6, 7 of the case body 5 are straight, and the outer peripheral surface of the cap 8 provided inside the ends 6, 7 is straight. In this case, a pair of ribs are formed on the outer peripheral surfaces of the ends 6, 7,
Concave peripheral grooves 11, 12 into which the tightening bands 9 fit are formed. Further, an uneven portion is formed on the inner peripheral surface 27 of the end portions 6 and 7 to make it difficult for the cap 8 to come off from the case body 5, and a Labins groove or an uneven strip portion is formed on the inner peripheral surface 32 of the cap 8. It is also free to prevent the cap 8 from coming off the sheath 2. It is also free to apply the contact plate 25 to the surface 17b of the outer flange 17 of each of the half bodies 5a, 5a. Note that the cap 8 is preferably formed from an elastic material such as rubber or synthetic resin. Further, in the illustrated example, the number of the branched fibers F is one, but it is needless to say that the number of the branched fibers F may be two or more. Further, in the illustrated example, the optical fiber units 3 are included in the sheath 2. Although the optical fiber cable 4 is used, it is also preferable to use an optical fiber cable 4 having an optical fiber core wire 48 in a straight line in the sheath 2. Further, the protective tube 36 may be formed of a long tubular body made of a flexible synthetic resin, rubber, or the like without using a metal flexible tube. Thus, it is also preferable that the protective tube 36 and the connecting member 35 are bonded. [Effects of the Invention] Since the present invention is configured as described above, the following effects can be obtained. The connecting member 35 does not fall out of the branch pipe portion 10 of the case main body 5 and the branch fiber protection tube 36 can be securely held in the case main body 5. It is protected and will not be damaged. The protection tube 36 with the connecting member 35 can be easily and reliably attached to the case body 5, and the cable branching operation is extremely easy. Since the retaining mechanism N is composed of a concave groove and a convex portion fitted into the concave groove, the structure is simple and reliable.
36 can be prevented from coming off. The retaining mechanism N including the concave groove and the convex portion can be easily provided, and the manufacture of the branch portion structure is easy.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an enlarged sectional view of an essential part showing an embodiment of the present invention, FIG.
The figure is a side view of the case body in a separated state, FIG. 3 is a perspective view of the cap, FIG. 4 is an enlarged sectional view of the optical fiber unit,
FIG. 5 is a side view, FIG. 6 is a rear view, FIG. 7 is an enlarged sectional view of a branch fiber protection tube, FIG. 8 is a simplified view for sequentially explaining a branching method, and FIG. FIG. 10 is a simplified side view showing an attached state, FIG. 10 is a front view thereof, FIG. 11 is an enlarged sectional view showing another embodiment of the retaining mechanism, and FIG. 12 is an enlarged view showing another embodiment of the retaining mechanism. FIG. 13 is a sectional view showing another embodiment of the case body. 2 ... sheath, 2a ... coated end, 3 ... optical fiber unit,
4 ... optical fiber cable, 5 ... case body, 10 ... branch tube part, 28 ... insertion hole, 35 ... connector, 36 ... protective tube, 48 ... optical fiber core wire, 52 ... open end, F ... branch fiber N: retaining mechanism.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Kaneko 4-3 Ikejiri, Itami City Mitsubishi Cable Industries, Ltd. Itami Works (58) Fields investigated (Int. Cl. ⁶ , DB name) G02B 6/00 336

Claims (1)

(57) [Claims] A branch structure for branching the optical fiber core or the optical fiber unit of the optical fiber cable having a plurality of optical fiber cores or optical fiber units inside the sheath, outside the sheath; A branch tube section for covering an optical fiber core or an optical fiber unit exposed from a coating end portion of the sheath at a predetermined portion of the cable, and guiding the optical fiber core or the branch fiber of the optical fiber unit to the outside. Has,
And a case main body comprising a pair of deployable or dividable half halves into which the base end of the branch fiber protection tube is inserted into the branch pipe portion, Fit freely,
A branch pipe portion of the case body is housed via a retaining mechanism comprising a concave groove and a convex portion fitted into the concave groove, and
It has an insertion hole through which the branch fiber is inserted, and the tip is inserted and fixed to the base end of the branch fiber protection tube,
A connector for attaching the branch fiber protection tube to the case main body. 2. A groove formed on the inner peripheral surface of the opening end of the branch pipe portion of the case main body, a projection formed at the base end of the connecting tool and fitted into the groove, 2. The optical fiber cable branch structure according to claim 1, wherein the optical fiber cable branch structure comprises: 3. The retaining mechanism, a concave groove formed at the base end of the coupling tool, and a convex portion formed on the inner peripheral surface of the open end of the branch pipe portion of the case body and fitted into the concave groove; 2. The optical fiber cable branch structure according to claim 1, wherein the optical fiber cable branch structure comprises: