JP2001337230A - Optical fiber cable closure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber cable closure with which the extra length segments of coated optical fibers are hardly movable in a tray. SOLUTION: This optical fiber cable closure has at least one tray 20 which has a spacer 34 having slots 36 on its outer periphery and a sheath 32 covering the spacer 34 and houses the extra length segments of the coated optical fibers 38 extending from the end of the optical fiber cable 2a disposed with the coated optical fibers 38 within the slits 36, a sleeve 10 which encloses the tray 20 and a supporting member 15 which fixes the optical fiber cable 2a to the sleeve 10. Further, the optical fiber cable closure has a region where the coated optical fibers 38 disposed in the slits 36 of the optical fiber cable 2a are exposed in the space from the supporting member 15 to the housing tray 20. A movement suppressing member 42 having compressibility is mounted at the outer periphery of the region where the coated optical fibers 38 are exposed. The coated optical fibers 38 are pressed to the spacer 34 within the slits 36 by the movement suppressing member 42.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical fiber cable closure (junction box) used at a branch point of an optical fiber cable or the like.

[0002]

2. Description of the Related Art At a branch point of an optical fiber communication network, an optical fiber cable closure (junction box) is used to connect optical fibers. FIG. 1 shows the appearance of a conventional optical fiber cable closure 1.

[0003] A closure 1 shown in FIG. 1 is a container that covers connection portions of a plurality of optical fiber cables 2a, 2b, 2c, and 2d. The connection of the optical fiber cables 2a to 2d is performed by fusing one end of an optical fiber core in one cable to one end of an optical fiber core in another cable. Since the fused portion is in a region where the coating of the optical fiber is stripped, it is weak against external stress and the like. The closure 1 is attached to the connection part of the optical fiber cables 2a to 2d so as to completely cover the fusion part.

A tray (not shown in FIG. 1) is usually provided in the closure 1, and a fusion portion of the optical fiber is located in the tray. In the tray, there is provided a space in which a part of the optical fiber is wound in a loop and stored. The portion of the optical fiber core housed in this space is referred to as the “extra length portion” of the optical fiber core. The extra length of the optical fiber core is not specifically fixed in the tray, and the movement of the optical fiber core is prevented only by the frictional resistance generated between the optical fiber core and the tray. For this reason, in the tray, the optical fiber core wire is likely to move due to vibration / impact or external force applied to the closure 1 or the fiber cables 2a to 2d.

[0005]

In recent years, tape slot type cable structures have been widely adopted. In this type of cable, a tape-shaped optical fiber core (tape core) is accommodated in a slot of a spacer having a slot (groove) extending long. The tape cores are not arranged so as to completely fill the slots, and a gap space is usually created in the slots. Therefore, when this type of cable is used, the optical fiber core wire tends to shift in the longitudinal direction of the cable, and as a result, the core wire movement within the tray is more likely to occur. When the extra length of the optical fiber core moves significantly in the tray, bending or side pressure of the optical fiber core causes a large distortion in a part of the optical fiber core, thereby increasing the transmission loss of the optical fiber core. There is a risk. If a stress equal to or less than the breaking stress is applied to the optical fiber for a long time, a defect or a scratch existing on or inside the glass grows and eventually breaks (static fatigue property).

The present invention has been made in view of the above points, and a main object of the present invention is to provide an optical fiber cable closure in which a surplus portion of an optical fiber core does not easily move in a tray.

[0007]

SUMMARY OF THE INVENTION An optical fiber cable closure according to the present invention comprises a spacer having a slot on the outer periphery, a sheath covering the spacer, and an optical fiber core disposed in the slot. A support member for fixing the optical fiber cable to the sleeve, the support member including at least one tray for storing an extra length of the optical fiber core extending from the end of the cable, a sleeve surrounding the tray, and the support member; A region from the member to the storage tray, in which the optical fiber core disposed in the slot of the optical fiber cable is exposed, wherein the optical fiber core is exposed; On the outer periphery of the is mounted a movement suppressing member having compressibility,
The optical fiber is pressed against the spacer in the slot by the movement suppressing member.

[0008] It is preferable that a gripping member surrounding the movement suppressing member and pressing the movement suppressing member toward the center of the optical fiber cable is further provided. The gripping member may be, for example, a binding band. It is preferable that the gripping member is formed of a plastic material or a metal material.

It is preferable that the movement suppressing member is formed of a gel material or a rubber material. Also, the gel material or rubber material forming the movement suppressing member may have a J shape.
The IS-A hardness is preferably in the range of 0 ° to 20 °, and more preferably in the range of 3 ° to 15 °.

The operation of the present invention will be described below.

In the optical fiber cable closure of the present invention, the optical fiber cable is fixed to the sleeve of the closure by a support member. The optical fiber core extending from the end of the optical fiber cable is stored in a storage tray. Each optical fiber core is connected to another optical fiber core in the storage tray as needed. In a region on the way from the support member to the storage tray, the sheath of the optical fiber cable is removed to form a region where the optical fiber is exposed in the slot. A movement suppressing member having compressibility is provided on the outer periphery of this area, and the movement suppressing member presses the optical fiber core wire in the slot against the spacer. The optical fiber core is prevented from moving with respect to the spacer by the pressing force of the movement suppressing member.

The movement suppressing member is preferably made of a material having high compressibility. For example, a material commercially available as gel or rubber can be suitably used. By using a gripping member such as a binding band to apply a pressing force in the direction of the spacer to a movement suppressing member (typically a film or plate) formed of a rubber material or a gel material, an optical fiber core is provided. Can be more effectively deterred.

The movement suppressing member is formed by using a material having high compressibility such as a gel material or a rubber material, and when a pressing force is applied to the spacer using the gripping member, the movement suppressing member is deformed, and the optical fiber cable is deformed. In this case, a part of the movement suppressing member projects into a space corresponding to a gap space formed between the groove in the spacer and the fiber, and a force for pressing the optical fiber core wire against the spacer acts strongly. This force can be applied by the elastic force of the movement suppressing member itself, for example, by providing the movement suppressing member (in the form of a rubber band) so as to surround the outer periphery of the spacer without providing the gripping member. Alternatively, it can be provided by separately providing (wrapping) a tape so as to surround the outer periphery of the movement suppressing member.

However, a gripping member is provided in a use condition in which the optical fiber core wire is likely to be displaced, for example, in a case where a long optical fiber cable is connected, in a use environment where a temperature difference is large, or in a use environment which is susceptible to vibration. Is preferred. The holding member is formed using a plastic material or a metal material.

[0015] As described above, the structure for suppressing the movement of the optical fiber core using the movement suppressing member can be easily formed and / or removed on the spot, so that the optical fiber cable closure already laid can be prevented. In addition to taking necessary measures, it is possible to cope with the addition and removal of optical fiber cables.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the optical fiber cable closure according to the present invention will be described below. Since the optical fiber cable closure according to the present invention has the same appearance as the conventional optical fiber cable closure 1 shown in FIG. 1, FIG. 1 is also used to describe the optical fiber cable closure of the present invention. FIG. 2 is a partially cutaway view of the optical fiber cable closure 1 shown in FIG.

As shown in FIG. 2, the optical fiber cable closure 1 of the present invention comprises a sleeve (housing) 10 and a tray 20 substantially surrounded by the sleeve 10 (see FIG. 3).
And a support member 15 for fixing the optical fiber cable 2a to the sleeve 10. The sleeve 10 has a substantially cylindrical shape, and is configured by combining a pair of semi-cylindrical portions. Optical fiber cable 2a
Is introduced into the inside of the sleeve 10 through the hollow portion of the ring-shaped grommet 50 provided at the circular openings formed at both ends of the sleeve 10. The tray 20 in the closure 1 is kept somewhat sealed from the outside by the grommet 50 and the sleeve 10. The tray 20 is fixed to the support member 15 by a connecting member 55 formed of, for example, metal. Note that the connecting member 55 may be omitted.

The optical fiber cable 2a has a tension member 33 at the center, and a spacer having a plurality of slots 36 on the outer periphery covers the tension member 33. An optical fiber core 38 is provided in the slot 36. Optical fiber cable 2 guided into closure 1
The sheath 32 is removed from the end of the spacer a between the support member 15 and the storage tray 20 and the spacer 34 is removed.
The optical fiber core wire 38 has an exposed area in the slot 36 of FIG. Further, the tension member 33 exposed at the distal end of the optical fiber cable 2a is fixed to the sleeve 10 by a tension member fixing member 57.

On the outer periphery of the region where the optical fiber core 38 is exposed in the slot 36, a movement suppressing member 42 having compressibility is mounted. It is preferable that the movement suppressing member 42 is formed of a gel material or a rubber material. The movement suppressing member 42 is pressed toward the center of the optical fiber cable 2a by a holding member 44 provided so as to surround the outer periphery thereof. The gripping member 44 is designed to exhibit a stable gripping force (restraint force) over a long period of time in a wide temperature range.
It is preferable to use a plastic material or a metal material. The optical fiber core 38 is pressed against the spacer 34 in the slot 36 by the movement suppressing member 42, so that the optical fiber core 38 is prevented from moving. The position at which the movement suppressing member 42 is provided is located between the tension member fixing member 57 and the support member 15.
It is preferable that the side be closer to the support member 15. For example,
As the optical fiber cables 2a to 2d, 100 optical fiber cables 2a to 2d (outside the cables) each having five fiber cores 38 (for example, a four-core tape) arranged in five slots (grooves) 36, respectively. Diameter 14mm, sheath 32
When the thickness is 1.5 mm, the diameter of the spacer 34 is 8.5 mm, the depth of the slot 36 is 2.2 mm, and the diameter of the tension member 33 is 1 to 2 mm, for example, the length of the exposed portion of the spacer 32 is 30 mm, The length of the exposed portion 33 (the portion visible in FIG. 2) is 1 to 2 mm, the width of the movement suppressing member 42 is 13 mm, and the thickness of the movement suppressing member 42 is 5 m.
m, the width of the gripping member 44 is 2 to 10 mm, and the thickness of the gripping member 44 is 1 to 3 mm.
8 can be suppressed. The above is merely an example, and can be changed as appropriate. The operation and effect of this configuration will be described later in detail with reference to FIG.

One end of each of the optical fiber core wires 38 of the optical fiber cables 2a to 2d is in an interconnected state in the tray 20. 3A and 3B show an external configuration of the storage tray 20 suitably used in the present embodiment.

One optical fiber cable closure 1
Inside, usually, a plurality of storage trays 20 are used in an overlapping manner. Each of the storage trays 20 is a rectangular container formed from a material such as general-purpose engineering plastic. The storage trays 20 are rotatably interconnected by hinges 27 provided on one of the long side end surfaces.

On the pair of short side end surfaces of the storage tray 20,
Each is provided with openings 21a and 21b for receiving a plurality of optical fiber core wires 38 therein.
For example, in the case where a 100-fiber optical fiber cable in which five fiber cores (for example, four-core tape) are arranged in five slots (grooves) as the optical fibers 2a to 2d, one slot is used. 5 / five optical fiber cores 38
Are connected in each storage tray 20.

The optical fiber ribbon 38 inserted into the tray 20 from the opening (first opening 21a) on the left side of the drawing, and the optical fiber core wire 38 inserted into the tray 20 from the opening (second opening 21b) on the right side of the drawing. The fiber optic cable 38 is fused at the center of the tray, thereby achieving the connection of the fiber optic cable. The fusion splicing is performed while the cut surfaces of the fibers are heated by an arc-type high-frequency discharge method, a micro torch method, or the like after the optical fibers are aligned. A fiber protection sleeve 2 formed of, for example, a transparent heat-shrinkable tube is provided at a connection portion of the optical fiber core 38.
8 is covered. The fiber protection sleeve 28 contracts due to the heating, and comes into close contact with the fused portion.

As the optical fiber core wire 38, for example, one obtained by coating an optical fiber with an ultraviolet curable resin is preferably used. This resin coating is usually composed of a primary coating layer located inside and a secondary coating layer located outside. A tape core wire used in a tape slot type cable is a cable in which a plurality of optical fibers arranged in a horizontal line are collectively covered with a resin.

From the tray openings 21a and 21b, the tray 2
The extra length of the optical fiber core wire 38 inserted into the inner space 0 is housed in a space (space) provided between the fiber connection portion and the tray openings 21a and 21b in a state of being wound in a loop. You. Due to the extra length, even if the optical fiber core wire 38 moves in the long axis direction of the cable due to an external force, no unnecessary force is applied to the fiber connection portion. The space for accommodating the extra length of the optical fiber core 38 is designed so as not to generate a large strain and stress that may cause transmission loss in the optical fiber core 38. For example, the loop diameter is 30-60 mm
It is preferable to provide a space that falls within the range. In addition, members (projections) 24 a, 24 b, 24 c, and 24 d for gently guiding the optical fiber core 38 are provided in the tray 20 in order to adjust the loop shape of the optical fiber core 38. These fiber guide members 24a to 24d are composed of, for example, small plate-like portions projecting from the inner wall surface of the tray 20, and sandwich the optical fiber core wire 38 between the plate-like portion and the inner wall of the tray 20. Is preferable. Such plate-like projections
Also provided near the tray openings 21a and 21b, the optical fiber core 38 is gently supported near the tray openings 21a and 21b.

In order to suppress the movement of the cord, a rubber pipe 22 may be attached to a part of the outer circumference of the extra length of the optical fiber cord 38. When the rubber pipe 22 is attached, the rubber pipe 2
Friction occurs between the tray 2 and the tray 20, and the movement of the cord can be suppressed by the friction. Rubber pipe 22
Is formed of, for example, silicone, and is spirally wound around the optical fiber core 38. The thickness of the rubber pipe 22 is set such that a part of the rubber pipe 22 is compressed between the optical fiber ribbon 38 and the plate-shaped protrusion near the tray openings 21a and 21b. Further, by forming the rubber pipe 22 so as to spirally wind around the plurality of optical fiber core wires 38, such a rubber pipe 22 can be connected to the existing closure already fused and connected in the tray 20. It can be easily applied to the optical fiber cores in the field.

The effect of suppressing the movement of the core wire by attaching the rubber pipe 22 to the optical fiber core wire 38 (resistance to pull out the core wire: about 100 g) is to press the optical fiber core wire 38 into the slot 36 by the movement suppressing member 42. Since the effect obtained by the configuration is lower than the effect obtained by the configuration (cord pull-out resistance: about 200 g or more), in a situation where the core wire movement occurs and is cheap,
It is preferable to use the movement suppressing member 42 together.

Next, with reference to FIG. 4, a configuration in which the optical fiber core 38 is pressed against the slot 36 by the movement suppressing member 42 and the operation and effect thereof will be described.

FIG. 4A is a schematic view of the end of the optical fiber cable 2a as viewed from the direction along the arrow in FIG. FIG. 4B is a schematic view illustrating another example of the gripping member 44.

Optical fiber cable (for example, 100 cores) 2
The optical fiber cores (for example, five four-core tapes in each slot 36) 38 in which the sheath 32 of FIG. Is pressed by the spacer 34.
The movement suppressing member 42 is pressed toward the center of the optical fiber cable 2a by a holding member 44 provided so as to surround the outer periphery thereof.

The movement suppressing member 42 is made of a material having high compressibility,
That is, it is preferable to use a gel material or a rubber material. Movement suppressing member 4 made of a material having high compressibility
When a compressive force is applied to the optical fiber cable 2a toward the center of the optical fiber cable 2, a part of the movement suppressing member 42 is deformed so as to fill a gap between the optical fiber cable 2a and the optical fiber core wire 38 in the slot 36,
A protrusion 42a is formed. That is, the gap formed between the sheath 32 of the optical fiber cable 2 a (holding tape when holding tape is provided) and the optical fiber core wire 38 in the slot 36 is formed by the movement suppressing member 4.
The optical fiber core 38 is substantially pressed by the two protrusions 42 a and pressed against the spacer 34.

Examples of preferable materials for forming the movement suppressing member 42 include gel materials such as silicone gel and polyethylene gel, EPDM (ethylene propylene rubber), silicone rubber, and polyethylene rubber. Among these, a material having a JIS-A hardness in the range of 0 ° to 20 ° is preferable because of its excellent adhesive strength.
Materials having an SA hardness in the range of 3 ° to 15 ° are more preferred. In particular, a polyethylene rubber and a polyethylene gel obtained by adding a paraffin oil to the polyethylene rubber are preferably used. The shape and size of the movement suppressing member 42 are not particularly limited, and may be appropriately set in consideration of the amount to be projected into the slot 36 so that the movement of the optical fiber core 38 in the slot 36 can be effectively suppressed. Good.

By providing the gripping member 44, about 7
A core wire pull-out resistance of 00 g to 800 g can be obtained. If there is a core wire pull-out resistance of about 700 g or more, the core wire movement can be suppressed even in a use environment where vibration is severe. As the holding member 44, a plastic or metal binding band or a hose band can be suitably used. For example, a binding band made of MC nylon may be used. Further, the clamp 46 as shown in FIG. 4B can be used instead of the gripping member 44. The clamp 46 is preferably made of plastic or metal. For example, a clamp 4 made of a plastic material such as MC nylon or PVC.
6 may be used. The shape and size of the gripping member 44 are not particularly limited, and are appropriately set so that the movement suppressing member 42 can be efficiently pressed toward the center of the optical fiber cable 2a.

The gripping member 44 can be omitted.
By providing the movement suppressing member 42 so as to surround the outer periphery of the spacer (in the form of a rubber band), a force for pressing the optical fiber cable 2a in the center direction can be given by the elastic force of the movement suppressing member 42 itself. Further, it can be provided by separately providing (wrapping) a tape so as to surround the outer periphery of the movement suppressing member 42. Even with the configuration in which the gripping member 44 is omitted, the value of the pull-out resistance of the optical fiber core wire 38 can be obtained from about 200 g to 400 g.

In the above embodiment, the present invention has been described with respect to a 100-fiber optical fiber cable provided with four-fiber ribbons, but the present invention is not limited to the above example. However, a tape slot type optical fiber cable having 100 fibers or less and being unidirectionally twisted particularly tends to move the core wire, so that a particularly great effect can be obtained by applying the present invention. Since an optical fiber cable having 200 or more cores has a large diameter of the spacer, the twisting force of the optical fiber core wire 38 is large, and the core wire misalignment is relatively unlikely to occur. Also, in the SZ twisted optical fiber cable, since the twisting force of the optical fiber core wire 38 is large, the core wire shift is relatively unlikely to occur.

[0036]

According to the present invention, even when a tape slot type optical fiber cable is used, the optical fiber core wire does not move easily. As a result, a large distortion does not occur in a part of the optical fiber core due to bending or lateral pressure of the optical fiber core, and a reduction in loss of the optical fiber core can be suppressed.

[Brief description of the drawings]

FIG. 1 is a diagram showing an appearance of an optical fiber cable closure 1. FIG.

FIG. 2 shows an optical fiber cable closure 1 according to the present invention.
FIG.

FIG. 3A is a front view of a tray used for the optical fiber cable closure of the present invention, and FIG. 3B is a perspective view thereof.

FIG. 4A is a schematic view of an end of an optical fiber cable installed in an optical fiber cable closure according to the present invention, as viewed from a direction along an arrow in FIG. 2;
(B) is a schematic diagram showing another example of a holding member used for the optical fiber cable closure according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Closure 10 Sleeve 15 Supporting tool 20 Storage tray 21a Tray opening 21b Tray opening 22 Rubber pipe 24a Optical fiber core guiding part 24b Optical fiber core guiding part 24c Optical fiber core guiding part 24d Optical fiber core guiding part 28 Fiber Protective sleeve 32 Sheath 33 Tension member 34 Spacer 36 Slot (groove) 38 Optical fiber core 42 Movement suppressing member 42a Movement suppressing member protrusion 44 Holding member (tie band) 46 Holding member (clamp) 50 Grommet 57 Tension member fixing member

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroaki Murata 4-3 Ikejiri, Itami-shi, Hyogo Mitsubishi Electric Cable Industries Co., Ltd. Itami Works (72) Inventor Takao Naito 6-2-7 Nakanoshima, Kita-ku, Osaka-shi, Osaka No. Osaka Media Port Co., Ltd. (72) Inventor Atsuto Ban No. 27, Nakanoshima 6-chome, Kita-ku, Osaka-shi, Osaka F-term (reference) 2H036 MA11 RA14 RA25 2H038 CA37 CA38

Claims (4)

[Claims] 1. An optical fiber core having a spacer having an outer peripheral slot and a sheath covering the spacer, the optical fiber core extending from an end of an optical fiber cable having an optical fiber core disposed in the slot. At least one tray for storing the extra length of the tray, a sleeve surrounding the tray, and a support member for fixing the optical fiber cable to the sleeve, between the support member and the storage tray. A region where the optical fiber core disposed in the slot of the optical fiber cable is exposed, and wherein a movement suppressing member having compressibility is provided on an outer periphery of the region where the optical fiber core is exposed. Is attached, and the optical fiber core wire is pressed by the movement suppressing member into the slot in the slot against the spacer. Ja. 2. The optical fiber cable closure according to claim 1, further comprising a gripping member surrounding the movement suppressing member and pressing the movement suppressing member toward a center of the optical fiber cable. 3. The optical fiber cable closure according to claim 1, wherein the movement suppressing member is formed of a gel material or a rubber material. 4. The JIS-compliant gel material or rubber material
The optical fiber cable closure according to claim 3, wherein the A hardness is in a range of 0 ° to 20 °.