JP2001066225A - Cover or door opening/closing detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve durability, reliability of a detector and also simplify a structure by inserting an optical fiber into a coiled spring. SOLUTION: An optical fiber 1 for giving a bending loss is inserted into a coiled spring 2 or a hard rubber tube, a first roller 3 is mounted at an end of a movable member moving in response to opening or closing of a cover or a door, and a plurality of second rollers 9 are disposed at both sides of the first roller 3 so as to sandwich the spring 2 or the tube containing the fiber 1. The spring 2 or the tube is constituted to be guided to the roller 3 so that the member 4 is biased by a compression spring 6, and moved to give bending of a curvature of the roller 3 to the spring 2 or the tube. For example, in a state such that a handhole cover is closed, the detector does not give bending to the fiber. In an opened state of the cover, the bending is given to the fiber to generate its loss.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lid or door opening / closing detecting device used for monitoring the opening / closing of a lid or a door installed at an entrance of an underground facility in a handhole or an electric wire common groove in an optical fiber line.

[0002]

2. Description of the Related Art Conventionally, for monitoring the opening and closing of a handhole cover or the like in an optical fiber line, an OTDR (Optical Time Domain Report) has been used.
The flectmeter method is widely known. In this OTDR method, as shown in FIG. 5, four handholes a, b, c, d
When the lids b and d are opened, the reflected light received by the OTDR changes abruptly at a position corresponding to the distance to b and d. Therefore, opening and closing of the handhole cover can be monitored by finding such a sudden change point of the reflected light power.

In the OTDR method, an open / close sensor using an optical fiber bending loss as shown in FIGS. 6 to 8 has been proposed. That is, in the open / close sensor shown in FIG. 8, when the drive rod 82 is removed by using the lid 81 of the handhole, the drive rod 82 moves upward due to the contraction of the spring 83, and the drive rod 8
The optical fiber 85 passed through the through hole 84 at the lower part of FIG.
A sharp bend as shown in (b) is generated, and the change in the reflection loss of the optical fiber is detected to detect the opening and closing of the handhole cover.

In the open / close sensor shown in FIG.
When the handhole cover 71 is opened (FIG. 7 (a) → FIG. 7).
(B)) The frame 72 is moved upward by the spring 73, and the optical fiber 70 is moved by the mandrel 74 attached to the frame 72.
It causes bending.

Further, in the open / close sensor shown in FIG. 6, an optical fiber core wire 60 wound around an elastically deformable fiber drum 62 is used as a sensor fiber, and a spring 63 is opened and closed by opening and closing a cover 61 such as a manhole. The fiber drum 62 is elastically deformed by the urging, and the change in the reflection loss of the optical fiber core caused by the deformation is detected.

[0006]

In such a conventional lid opening / closing sensor, even if the optical fiber is bent after being bent, the optical fiber does not return to the original state (a state in which loss is eliminated). There is a disadvantage that there is a possibility that recognition of opening and closing is not performed.

Further, the open / close sensor shown in FIG. 6 which solves this problem has a disadvantage that the structure is complicated and the sensor itself becomes large. Further, since all of the above open / close sensors apply an external force directly to the optical fiber, they are covered with an appropriate coating material, but mechanical damage such as breakage cannot be denied over a long period of use.

An object of the present invention is to provide a lid or door opening / closing detecting device which solves the conventional problems, improves durability and reliability, and has a simplified structure.

[0009]

According to the present invention, there is provided a lid or door opening / closing detecting device, comprising: a movable member which moves in accordance with opening / closing of a lid or a door; a supporting / fixing member which slidably supports the movable member; A spring that expands and contracts by the movement of the movable member, and a unit that bends the optical fiber by moving the movable member by urging the spring when the lid or door is open, to apply a bend to the optical fiber. A device for detecting a change in transmission loss or reflection loss of an optical fiber caused by the optical fiber, wherein the optical fiber is inserted into a coil spring. Further, the optical fiber is inserted into a hard rubber tube.

In the present invention, an optical fiber giving bending loss is inserted into a coil spring or a hard rubber tube, and a first roller is attached to the tip of a movable member which moves according to opening and closing of a lid or a door. A plurality of second rollers are arranged on both sides of one roller so as to sandwich a coil spring or a hard rubber tube containing an optical fiber, and the coil spring or the hard rubber tube is guided to the first roller. Is moved by being urged by the compression spring, so that the curvature of the first roller is given to the coil spring or the hard rubber tube.

In another aspect of the present invention, an optical fiber giving bending loss is inserted into a coil spring or a hard rubber tube, and a roller is attached to the tip of the movable member.
The coil spring or the hard rubber tube is fixed to both ends so that the coil spring or the hard rubber tube is suspended by the roller to form an inverted U shape, and the coil spring or the hard rubber tube containing the optical fiber is such that the movable member is When the compression spring is moved in the direction of compressing, the roller is released from the restraint by the roller, and when the movable member is moved by being urged by the compression spring, bending of the curvature of the roller is applied to the coil spring or the hard rubber tube. It is characterized by the following.

[0012]

Embodiments of the present invention will be described with reference to the drawings. FIGS. 1A, 1B and 2 show an embodiment of the present invention. FIG. 1 is a view showing a state when a handhole lid is closed, and FIG. It is the A arrow view of (a). FIG. 2 shows a state where the lid is opened.

An optical fiber 1 for giving a bending loss is provided in a coil spring 2 so as to bend by a roller 3 as a first roller. One end of the coil spring 2 containing the optical fiber 1 is fixed by a fixing portion 12, and the other end is a free end protruding outside the case through the through hole 11 of the case 10. The optical fiber 1 is guided to the outside of the case 10 through the through holes 11 and 13 of the case 10, is connected to an optical fiber cable (not shown), and is connected to a similar device or a monitoring center installed in another handhole.

Next, a specific embodiment of the apparatus will be described with reference to FIGS. The movable member 4 that moves up and down in response to opening and closing of the handhole cover is movably supported by a supporting and fixing member 5 through which the movable member 4 penetrates, and a compression spring 6 is inserted through the movable member 4. The movable member 4 is provided with a guide rod 7 for movement, and the lower end of the movable member 4 is provided with a roller 3 for bending. A roller 8 for smoothly transmitting the vertical movement force is attached to the upper end of the movable member 4, but this is not an essential component.

Two sets of rollers 9 are arranged on both sides of the roller 3 so as to sandwich the coil spring 2 having an optical fiber inserted therein.

Next, the operation of the apparatus will be described. For example, when the handhole cover is closed, the apparatus is in the state shown in FIG. 1 and does not bend the optical fiber. When the lid is open, the apparatus is in the state shown in FIG. 2, and the optical fiber is bent to generate a loss. Next, when the optical fiber is closed again as shown in FIG. 1, the bent optical fiber becomes a linear state due to the restoring force of the coil spring, and the loss is completely eliminated.

As described above, in the present apparatus, since the bending is given through the coil spring, no mechanical damage is given to the optical fiber. In addition, since the coil spring is bent by the roller, the coil spring is not damaged.
Further, the coil spring can be smoothly bent by the guide of the roller. Furthermore, it is structurally simple.

FIGS. 3 and 4 show another embodiment of the present invention. FIG. 3 is a view showing a state where the handhole lid is closed, and FIG. 4 is a view showing a state where the handhole lid is opened. Indicates the status.

An optical fiber 31 for giving a bending loss is passed through a coil spring 32, and both ends of the coil spring 32 are fixed to a case 30 by a fixing portion 39 such that the coil spring 32 has a substantially inverted U shape. ing.

A compression spring 36 is inserted through a movable member 34 which moves up and down in response to opening and closing of the handhole cover.
A guide rod 37 for moving up and down is provided.
A roller 33 that is movably supported through a through hole 40 provided in the supporting and fixing member 35 and that applies a bending loss to the lower end of the movable member 34 is attached. A roller 38 for smoothly transmitting the vertical movement is attached to the upper end of the movable member 34. The roller 38 is not an essential component.

Next, the operation of the apparatus will be described. For example, when the handhole cover is closed, the apparatus is in the state shown in FIG. 3, and the bending of the optical fiber (coil spring 32) in this state is caused by bending loss. Is not given.

In the state where the cover is opened, as shown in FIG. 4, the movable member 34 is urged by the compression spring 36 to move upward, so that the optical fiber 3 is moved by the roller 33.
1 is bent until a bending loss occurs, causing a loss.

Next, when the lid is closed again, the state shown in FIG. 3 is obtained. However, the optical fiber 31 that has been bent until the loss occurs is initially bent without loss due to the restoring force of the coil spring 32. And the loss is completely eliminated.

In this manner, the optical fiber is bent via the coil spring 32, so that the optical fiber is not mechanically damaged.
Further, since the coil spring 32 is bent by the roller 33, the coil spring 32 is not damaged. In terms of structure, it becomes even simpler than the above-described opening / closing detection device of FIG.

In each of FIGS. 1 and 3, the magnitude of the applied loss can be adjusted by adjusting the outer diameter of the coil spring and the roller and the movable range of the roller. The materials of the coil spring and the roller are not particularly limited.

Another embodiment of the present invention is that the coil springs 2 and 32 in FIGS. 1 and 3 are hard rubber tubes. In this case, the operation and effect of the present invention described above do not change.

In the above-described embodiment, the case where the movable member is moved up and down has been described. However, it is needless to say that the present invention can be implemented with exactly the same configuration when the movable member is moved left and right.

[0028]

The present invention has the following effects.

1) Since the optical fiber is contained in the coil spring or the hard rubber tube, even if the optical fiber is once bent, the optical fiber returns to the linear state or the original state due to the restoring force of the coil spring or the hard rubber tube, and the bending loss. Completely disappears.
Therefore, the detection accuracy is improved.

2) The optical fiber is bent by applying an external force to the coil spring or the hard rubber tube by a roller, so that the optical fiber is not damaged and the coil spring or the hard rubber tube is not damaged. Therefore, it is excellent in durability.

3) Since the strength of the loss can be adjusted by the outer diameter of the coil spring or the hard rubber tube and the roller, the sensitivity can be easily adjusted when there are a plurality of monitored objects.

4) Since the optical fiber is accommodated in a coil spring or a hard rubber tube and subjected to loss bending by a roller, the structure is not complicated.

[Brief description of the drawings]

FIG. 1 is a front view showing a state when a handhole cover is closed according to an embodiment of the present invention.

FIG. 2 is a front view showing a state where the state of FIG. 1 is changed to a state when a handhole cover is opened.

FIG. 3 is a front view showing a state when a handhole cover is closed according to another embodiment of the present invention.

FIG. 4 is a front view showing that the state of FIG. 3 has changed to the state when the handhole cover is opened.

FIG. 5 is an explanatory diagram of the OTDR method according to the present invention.

FIG. 6 shows an example of a lid opening / closing sensor for a manhole or the like in the prior art.

FIG. 7 shows another example of a lid opening / closing sensor for a manhole or the like in the prior art.

FIG. 8 shows still another example of a cover opening / closing sensor for a manhole or the like in the prior art.

[Explanation of symbols]

 1,31 Optical fiber 2,32 Coil spring 3,33 Roller 4,34 Movable member 6,36 Compression spring 7,37 Guide rod 10,30 Case

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masao Saito 42-1 Shintomi, Futtsu-shi, Chiba F-term in Fujikura Futtsu Works (reference) 2G086 CC02 DD05 2H038 AA05

Claims (5)

[Claims] A movable member that moves in accordance with opening and closing of a lid or a door, a supporting and fixing member that slidably supports the movable member, a spring that expands and contracts by the movement of the movable member, and a lid or a door that opens. Means for bending the optical fiber by moving the movable member by the bias of the spring at the time of detecting the change in transmission loss or reflection loss of the optical fiber caused by bending the optical fiber. A lid or door opening / closing detecting device, wherein the optical fiber is inserted into a coil spring. 2. A movable member that moves in accordance with opening and closing of a lid or a door, a supporting and fixing member that slidably supports the movable member, a spring that expands and contracts by the movement of the movable member, and a lid or a door that opens. Means for bending the optical fiber by moving the movable member by the bias of the spring at the time of detecting the change in transmission loss or reflection loss of the optical fiber caused by bending the optical fiber. A lid or door opening / closing detecting device, wherein the optical fiber is inserted into a hard rubber tube. 3. A movable member that moves in accordance with opening and closing of a lid or a door, a supporting and fixing member through which the movable member penetrates, and an optical fiber disposed in a moving direction of the movable member.
A compression spring is inserted through the movable member, and when the lid or door is closed, the optical fiber is released from bending by moving the movable member by compressing the compression spring by the lid or door, When the lid or door is open, the compressed member is urged by the compressed spring to move the movable member in the opposite direction, thereby bending the optical fiber to cause transmission loss or reflection of the optical fiber. An apparatus for detecting a change in loss, wherein the optical fiber is inserted into a coil spring or a hard rubber tube, and a first roller is attached to a tip of the movable member,
A plurality of second rollers having a rotation axis parallel to the rotation axis of the first roller are arranged on both sides of the first roller so as to sandwich a coil spring or a hard rubber tube containing the optical fiber, A cover or a hard rubber tube, wherein the movable member is biased by the compression spring and moved to apply a curvature of the first roller to the coil spring or the hard rubber tube containing the optical fiber. Door open / close detector. 4. The lid or door opening / closing detecting device according to claim 3, wherein one end of the coil spring or the hard rubber tube containing the optical fiber is fixed, and the other end is slidable. 5. A movable member that moves in accordance with opening and closing of a lid or a door, a supporting and fixing member through which the movable member penetrates, and an optical fiber disposed in a moving direction of the movable member.
A compression spring is inserted through the movable member, and when the lid or door is closed, the optical fiber is released from the constraint by moving the movable member by compressing the compression spring by the lid or door, When the lid or door is open, the compressed member is urged by the compressed spring to move the movable member in the opposite direction, thereby bending the optical fiber to cause transmission loss or reflection of the optical fiber. A device for detecting a change in loss, wherein the optical fiber is housed in a coil spring or a hard rubber tube, a roller is mounted on the tip of the movable member, and the coil spring or hard rubber tube housing the optical fiber is A coil spring or a hard rubber tube containing the optical fiber is formed by being suspended on a roller and having both ends fixed in an inverted U-shape, When the movable member moves in the direction of compressing the compression spring, the movable member is released from the restraint by the roller, and when the movable member moves by being urged by the compression spring, the curvature of the roller is given a curvature. A lid or door opening / closing detection device, characterized in that: