JPH0313904A - Water immersion sensor tool - Google Patents

Abstract

PURPOSE:To prevent a caulking force from being applied to a coated optical fiber and to prevent optical transmission loss from varying greatly by clamping the coated optical fiber elastically by an elastic body and fixing it at a specific position. CONSTITUTION:Fixtures 34' and 35' of the water immersion sensor tool consists of couples prismatic rubber elastic bodies respectively and clamp coated optical fibers 5 and 5a running through an insertion path. Then when the coated optical fibers 5 and 5a are fitted and fixed to a casing, one elastic body of each of fixtures 34' and 35' is pressed to one elastic body of each of the fixtures 34' and 35' against the spring elasticity of a spring member 51 to increase the interval between the couples of elastic bodies, the coated optical fibers 5 and 5a are inserted in said state, and the elastic bodies are released from being pressed to clamp the fibers by both elastic bodies elastically. Therefore, no caulking force is applied to the coated optical fibers and the optical transmission loss never varies greatly owing to the cracking of the optical fibers.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a water immersion sensor device used to detect water intrusion into a cylindrical closure housing a connecting portion of an optical fiber cable.

[Conventional technology]

Conventional communication networks use copper cables, and if the copper wires in the copper cables get wet, communication will be disrupted.
An important issue was to prevent the outer surface of the copper wire cable from being damaged and the internal copper wires from flooding. To prevent the above-mentioned flooding, a measure called the so-called "gas maintenance method" has usually been taken. This is because a certain amount of gas is always sealed inside the cable and kept at a certain pressure, and when the gas leaks out of the cable, the above pressure decreases, causing damage to the cable (and eventually water intrusion into the cable). The purpose is to detect the situation.

However, recently, optical fiber cables have been used instead of the copper wire cables mentioned above, and since the optical fiber core wires used for communication in these optical fiber cables are sufficiently protected, water intrusion etc. can only be detected at the connection part. It is now sufficient to maintain and manage the system.

[Problem that the invention seeks to solve]

This type of optical fiber cable end connection generally uses a cylindrical closure, in which one end of the optical fiber cable is introduced into the closure from one end face, and the other end of the optical fiber cable is inserted from the other end face. The optical fibers are introduced and pulled out from both ends and are connected with their ends butted against each other. It is not appropriate to use the conventional gas maintenance method for the connection portion of an optical fiber cable having such a structure because of problems such as structural problems and management costs. For this reason, the present inventors have developed and researched a water immersion sensor device that is easy to maintain, has a long life, and can be miniaturized, and has already filed a patent application (Japanese Patent Application No. 1-51768). As shown in FIG. 5, the water immersion sensor device 8 is disposed at the bottom of the cylindrical closure 6, and the optical fiber core wires 5, which are pulled out from a pair of left and right optical fiber cables 11a introduced into the closure 6, 5a
is housed inside. In Figure 5,
2 and 2a are cable gripping parts, 3.3a is a tension member, 4 and 4a are tension member gripping parts, 10 is a connection part storage part (excess length processing part) for optical fiber core wires 5 and 5a, and 7 is an end plate. be. The water immersion sensor device 8 according to this proposal is a lowermost optical fiber core 5 that is not used for optical communication.
, 5a, as shown in FIG. 6 and FIG. The casing 20 is
It is provided with a lid body 2'Oa with a through hole on the upper surface for removably covering the lid. The rectangular box-shaped casing 20 has a chamber block 22 on the left side from the center in the longitudinal direction, and a solid block 23 on the right side. As shown in FIG. 7, inside the chamber block 22 on the left side of the box-shaped casing 20, a central protrusion 25 with a first central groove 24 extends from one longitudinal end to the other end. The ridge 25 extends to the chamber block 2 of the casing.
The interior of 2 is divided into two chambers 26 and 27, left and right. Further, a second central groove 24 is provided in the solid block 23 of the casing 20 with the first central groove 24 of the central protrusion 25 extended.
A central groove 28 is formed extending to the end of the casing 20. In this case, one groove wall of the second central groove 28 is greatly hollowed out in an arch shape as shown in the figure, and that portion is formed into a large recess 29. At the entrance side portion of the second central groove 28, opposing groove walls are hollowed out so that the entire entrance is formed into an arch-shaped groove guide portion 30. Further, the outlet side portion of the second central groove 28 is formed into a rectangular fixture housing chamber 31a. In the two left and right chambers 26.27 divided by the central protrusion 25, water-absorbing and expanding materials 31 each having a shape that fits within the two chambers 26.27 are disposed. These water-absorbing and swelling materials at are composed of a water-absorbing and swelling rubber that has ethylene-propylene-diene rubber (EPDM) as its main component and has a water-swelling agent and a water-absorbing agent dispersed throughout. Reference numeral 32 denotes a fixed plate which is formed into a substantially U-shape, and both sides of the U-shape are connected to the left and right water-absorbing and expanding materials 3.
It is arranged in the chamber block 22 with the U-shaped vertical side aligned with the outer surface of the tube 1 and along the front end surfaces of both the water-absorbing and expanding materials 31 and the front end surface of the central protrusion 25. In this chamber block 22', the space between the boundary wall between the solid block 23 and the chamber block 22 and the U-shaped vertical side of the U-shaped fixing plate 32 is formed by water absorption and expansion of the water absorption and expansion material 31. This provides a movement space when the fixed plate 32 moves to the right in the drawing due to the pressing force. And the solid part block 23
A boundary wall 33 between the chamber block 22 and the chamber block 22 serves as a stopper for the movement of the fixed plate 32. Reference numeral 34 denotes a first fixing metal fitting, which is arranged in the first and second central grooves 24.28 and is inserted across the casing 20 in the optical fiber cores 5, 5a, and is attached to the front end of the water-absorbing and expanding material 31. The portion of the optical fiber core 5.5a corresponding to the surface is fixed on the fixing plate 32.
It is fixed to the front end surface of the water-absorbing and expanding material 31 via. 35 is a second fixture, which is located in the fixture housing chamber 3 of the solid block 23.
A portion of the optical fiber core 55a corresponding to 1a is fixed to a corner of the inner wall surface of the fixture storage chamber 31. In addition, 36 is a notch hole provided in the fixing plate 32 for passing the optical fiber core wires 5, 5a, and 37 is a protrusion that fits into the upper part of the fixing device storage chamber 31a when the lid is closed.

In this configuration, the optical fiber core wires 5, 5a are connected to the first casing 20 as shown in FIG.
positioned within the second central groove 24.28 and a predetermined portion thereof into the first. It is arranged in a fixed state with a second fixture 34,35. In this case, the inlet portion 30 of the second central groove 28
Since the area is wide, installation work is easy.

Next, the box-shaped casing 20 through which the optical fiber core wires 5 and 5a are passed is covered with M20a, and the water immersion sensor device 8 is covered with M20a.
This is arranged at the bottom of the closure 6 with the longitudinal direction of the casing 20 aligned with the axial direction of the closure 6 as shown in FIG. In this state, when water enters the closure 6, the water passes through the hole in the bottom of the box-shaped casing 20 and is absorbed by the water-absorbing and expanding material 31. In this case, the rectangular box-shaped casing 20 is arranged with its longitudinal direction aligned with the longitudinal direction of the cylindrical closure 6 (coaxially), and with its longitudinal direction perpendicular to the longitudinal direction of the closure 6. Since it is not disposed, the bottom surface of the casing 20 is relatively close to the bottom surface of the cylindrical closure 6. therefore,
This is advantageous for early detection of flooding. As the water absorption and expansion material 31 absorbs water, the water absorption and expansion material 31 swells rapidly and pushes the fixing plate 32 from the solid line position in FIG. 6 to the position shown by the chain line A to the stopper part 33. The optical fiber core wires 5, 5a, which were straight in the non-water absorption state, are bent as shown by the chain line B in the recess 29 of the second central groove 28, thereby increasing the transmission loss of light. Therefore, by detecting this, it becomes possible to quickly and accurately grasp water intrusion inside the closure 6. In this case, the bending of the optical fiber core wires 5, 5a is regulated by the action of the stopper part 33 at a stage before permanent deformation occurs, and the bending is made along the arch shape of the recess 29, so that the bending is performed inside the closure 6. When the water subsides and the state returns to normal, the optical fiber cores 5, 5a return to their initial shapes and do not cause any problems.

However, since the water immersion sensor device according to the above proposal uses a fixing device 34.35 made of a caulking member as shown in FIG. There is a problem in that the optical fibers of the optical fiber core wires 5, 5a are cracked during crimping, which causes large variations in optical transmission loss. In addition, since there are various types of optical fiber cores 5.5a such as single core, two cores, four cores, five cores, and multiple cores, prepare a caulking member with a size corresponding to each type and use it to fix it. There is also the issue of having to do this.

This invention was made in view of the above circumstances, and it does not cause cracks in the optical fiber when fixing the optical fiber core, and can be applied to optical fiber cores of any size without using special fixing tools. Its purpose is to provide a water immersion sensor device.

[Means for solving problems]

In order to achieve the above object, the water immersion sensor device of the present invention is disposed on the bottom part of a cylindrical closure that coaxially accommodates a connection part that connects the ends of one optical fiber cable and the other end of the optical fiber cable. and a box-shaped casing that accommodates any one of the plurality of optical fiber cores pulled out and connected from the end of the other optical fiber cable, the box-shaped casing having at least the bottom side formed as a water absorption part. , an optical fiber outlet formed opposite to each other on both end faces perpendicular to the axial direction of the casing, and an optical fiber outlet that is housed in the box-shaped casing with the axial directions aligned, and one end in the axial direction is located at one end of the casing. abutting,
a water-absorbing expandable material whose other end is a free end facing the other end of the casing with a space therebetween; a stopper portion provided between the other end of the casing and the free end of the water-absorbing expandable material; , a first fixing means for fixing to the free end a portion of the optical fiber core that traverses inside the box-shaped casing, and a portion of the optical fiber core that corresponds to the other end of the box-shaped casing; A second fixing means fixed to the other end is provided, and the fixing means includes an elastic body that elastically clamps the optical fiber core wire, and a fixing part that fixes the elastic body to the predetermined portion of the box-shaped casing. The structure is as follows.

[Effect]

That is, in this water immersion sensor device, the optical fiber core wire is fixed by elastically sandwiching the optical fiber core wire between elastic members, and then fixed to a fixing portion provided in a box-shaped casing. Therefore, when fixing the optical fiber core wire, there is no need for caulking work as in the above-mentioned proposal, so that cracks do not occur in the optical fiber. Furthermore, since the optical fibers are clamped and fixed using the elasticity of the elastic body, even if the optical fibers have different dimensions, this can be absorbed by the elasticity of the elastic body and can be adequately accommodated. Therefore, there is no need to use caulking members that match the dimensions of each optical fiber core wire, as in the case of the above-mentioned proposal.

Next, examples will be described.

〔Example〕

FIG. 1 is an exploded perspective view of an embodiment of the present invention. This water immersion sensor device has a sliding lid 20a with a sliding elongated hole 20b on its side, and fixtures 34' and 3.
5' is made of an elastic member such as rubber, and this is formed into a recessed part 34'.
a, 35' It is substantially the same as the water immersion sensor device shown in FIG. 6, except that it is housed and fixed in a. Therefore, the same or corresponding parts are given the same reference numerals and repeated explanation will be omitted.

The fixtures 34', 35' and their accommodation recesses 34'
a, 35' To explain a in more detail, the fixtures 34', 35' each consist of a set of two prismatic rubber elastic bodies, and are attached to the fixing plate 32 in the box-shaped casing and near the optical fiber outlet. Two IIJ are provided in the section with the insertion path for the optical fiber core wires 5 and 5a sandwiched between them.
The optical fiber cores 5 and 5a are accommodated in the recesses 34'a and 35'a of 1 and elastically sandwich the optical fiber cores 5 and 5a passing through the insertion path. Of the pair of rubber elastic bodies, one of the elastic bodies is biased by a spring member 51 via a stainless steel plate 50, as shown in FIG. 50
is a cylindrical hole provided for accommodating and fixing the spring member 51.

With this configuration, the optical fiber core wire 55a can be attached and fixed to the casing by pressing one of the elastic bodies of the fixing members 34' and 35' against the spring elasticity of the spring member 51, and pressing the elastic bodies of the two IMi. This can be easily carried out by widening the gap, inserting the optical fiber core wires 5, 5a between them in that state, releasing the above-mentioned pressure, and making them elastically sandwiched between the above-mentioned elastic bodies. Therefore, optical fiber core wire 5.5a
When installing and fixing the optical fiber, there is no need to apply excessive force as with caulking, so there is no chance of cracks in the optical fiber. Moreover, even if optical fiber core wires have various sizes, the difference in size is absorbed by the elasticity of both the elastic bodies and the spring elasticity of the spring member 51, so that the present invention can be applied without any problems.

Incidentally, instead of the spring member 51, a screw member 53 as shown in FIG. 3 may be used, and the tightening degree may be adjusted to correspond to the difference in the dimensions of the optical fiber core wire. 54 is a knob.

FIG. 4 is a perspective view of another embodiment of the invention. That is, in this embodiment, in the box-shaped casing 26, a substantially semicircular water-absorbing and expanding material 55 is disposed between the stopper part 33 and the end of the box-shaped casing, and the optical fiber core wires 5, 5a
Also on the side surface, the water-absorbing and expanding material 55 absorbs water and expands to add a dove pattern. The other parts are the first
Same as the figure. Therefore, optical fiber core 5.5
Not only the compressive force in the axial direction but also the pressure in the direction perpendicular to the axis is applied to the optical fiber core 5,
5a begins to bend in a short period of time after the start of flooding. As a result, it becomes possible to shorten the time required to detect water intrusion.

〔Effect of the invention〕

The water immersion sensor device of the present invention is one in which the optical fiber core is elastically sandwiched between elastic bodies and fixed to a predetermined portion, and is not fixed using a caulking tool as in the above-mentioned proposal. Therefore, no caulking force is applied to the optical fiber core wire, and as a result, a situation in which the optical fiber is cracked and the optical transmission loss varies greatly does not occur. Furthermore, the difference in size can be absorbed by the elastic deformation of the elastic body for various types of optical fiber core wires having different sizes. Therefore, the complicated work of preparing caulking tools for each dimension of the optical fiber core wire and attaching them in accordance with the dimensions of the optical fiber core wire, as in the above-mentioned proposal, becomes unnecessary.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of an embodiment of the present invention with the lid removed, Fig. 2 is an explanatory view of the optical fiber core in a clamped and fixed state, Fig. 3 is an explanatory view of a modification thereof, and Fig. 4 5 is a perspective view of another embodiment with the lid removed, FIG. 5 is a cross-sectional view of the water immersion sensor device, which is the basis of this invention, housed in the closure, and FIG. 6 is the water immersion sensor device of FIG. 5. 7 is an exploded perspective view thereof, and FIG. 8 is a perspective view of the optical fiber core with a caulking member attached to the optical fiber core. 5.5a... Optical fiber core wire 20... Box-shaped casing 20a... Lid body 31... Water absorption and expansion material 3
2...Fixing plate 33...Stopper part 34', 3
5'...Fixing device 34'a consisting of a pair of rubber elastic bodies
. 35'a...accommodating recess

Claims (1)

[Claims] (1) Disposed on the bottom of a cylindrical closure that coaxially accommodates a connection part that connects the ends of one and the other optical fiber cables, and is pulled out and connected from the ends of the one and other optical fiber cables. A water immersion sensor device that accommodates any one of a plurality of optical fiber cores, which includes a box-shaped casing in which at least the bottom side is formed as a water absorption part, and two opposite end faces perpendicular to the axial direction of the casing. An optical fiber outlet formed in a facing state is housed in the box-shaped casing with their axial directions aligned, one end in the axial direction abuts one end of the casing, and the other end contacts the other end of the casing. A water-absorbing expandable material whose free ends face each other while maintaining a space, a stopper portion provided between the other end of the casing and the free end of the water-absorbing expandable material, and an optical fiber core that crosses inside the box-shaped casing. a first fixing means for fixing a portion of the wire corresponding to the free end to the free end; and a second fixing means for fixing a portion of the optical fiber core corresponding to the other end of the box-shaped casing to the other end. 1. A water immersion sensor device, characterized in that the fixing means comprises an elastic body that elastically clamps the optical fiber core, and a fixing part that fixes the elastic body to the predetermined portion of the box-shaped casing.