JP2000193413A - Displacement sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a displacement sensor using an optical fiber. SOLUTION: A displacement sensor is constituted in such a way that first and second fixed members 11 and 12 are fixed to an object to be measured and first and second attached members 21 and 22 are attached to the members 11 and 12 so that tension may be generated in an optical fiber 4 stretched between the fixed members 21 and 22 in accordance with the variation of the displacement of the object and finds the displacement of the object by measuring the tension of the fiber 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a displacement sensor.

[0002]

2. Description of the Related Art Conventionally, displacement sensors include those utilizing characteristics of tension and vibration of a piano wire and those utilizing characteristics of electric resistance and tension. However, these displacement sensors require a great deal of maintenance and management work, such as the need for a power supply.

[0003]

<A> The present invention is to provide a displacement sensor using an optical fiber. <B> The present invention is to provide a displacement sensor that can be easily managed.

[0004]

SUMMARY OF THE INVENTION The present invention provides a first fixing member and a second fixing member fixed to an object to be measured, a first fixing member mounted on the first fixing member, and a second fixing member. A second attachment member attached, a holding member that holds the first attachment member and the second attachment member such that a gap between the first attachment member and the second attachment member changes according to the displacement of the device under test, First
A displacement sensor comprising an optical fiber stretched between the mounting member and the second mounting member, measuring the tension of the optical fiber, and determining the displacement of the object to be measured, or the displacement sensor, The first mounting member includes a first bobbin rotatable with respect to the first fixing member, and the second mounting member includes a second bobbin rotatable with respect to the second fixing member. In the sensor or the displacement sensor, each of the first and second bobbins includes a plurality of independently rotating bobbins, and a plurality of optical fibers are arranged between the first and second bobbins. In the displacement sensor or the displacement sensor, the holding member is formed of a shaft, and is slidably held with respect to the first fixed member and the second fixed member. An optical fiber that is connected in series with the optical fiber stretched between the first holding member and the second holding member, and that is arranged without applying tension near the optical fiber. A displacement sensor.

[0005]

Embodiments of the present invention will be described below with reference to the drawings.

<A> Overview of Displacement Sensor A displacement sensor measures the displacement of an object to be measured by measuring the tension applied to the optical fiber using an optical fiber, and measures various objects to be measured such as ground and concrete structures. Can be measured.

[0007] The displacement sensor has a structure in which tension is applied to the optical fiber in accordance with the displacement of the object to be measured. When tension is applied to a predetermined portion of the optical fiber, the position and strain of the tension portion can be measured, so that the displacement applied to the measured object can be obtained.

<B> Structure of Displacement Sensor As shown in FIG. 1, the displacement sensor includes a first fixing member 11 and a second fixing member 12 which are fixed to an object to be measured.
A first attachment member 21 is attached to the fixing member 11, and a second attachment member 22 is attached to the second fixing member 12. The holding member 3 is arranged so that the gap between the first fixing member 11 and the second fixing member 12 can be freely changed. The optical fiber 4 is tensioned between the first mounting member 21 and the second mounting member 22 as a tension portion 41, and the correction optical fiber 4 is connected in series with the optical fiber 4 to form a correction portion 42. A detecting device 5 is connected to one end of the optical fiber 4, and the tension of the optical fiber 4 is measured.

<C> Fixing Member The fixing member is to be fixed to an object to be measured for displacement, and the first fixing member 11 and the second fixing member 12 are
The first fixed member 11 and the second fixed member 12 are fixed to an object to be measured and are arranged so as to change in accordance with the magnitude of displacement of the object to be measured. First fixing member 1 as a fixing member
Taking the first fixing member 1 as an example, as shown in FIGS.
The first fixing member 11 is fixed to the object to be measured by fixing the fixing metal 112 to one end of the first object, fixing the fixing metal 112 to the object to be measured with screws. When the slide mechanism is provided between the first fixing member 11 and the fixing fitting 112, the fixing position of the first fixing member 11 and the fixing fitting 112 can be easily adjusted.

<D> Mounting Member The mounting member stretches the optical fiber 4. The first mounting member 21 is mounted on the first fixing member 11, and the second mounting member 22 is mounted on the second fixing member 12. . The tension is applied to the tension portion 41 of the optical fiber 4 in accordance with a change in the gap distance between the first fixing member 11 and the second fixing member 12. Taking the first mounting member 21 as an example of the mounting member, the rotatable bobbin 211 is mounted on the first fixing member 11 as shown in FIGS. The first mounting member 21 and the second
When arranging the optical fiber 4 multiple times between the mounting members 22, a plurality of independently rotating bobbins 211 are arranged. The bobbin 211 is attached to the first fixing member 11 with a bobbin nut 212.

<E> Holding Member The holding member 3 holds the gap between the first fixing member 11 and the second fixing member 12 so as to be freely changed. For example, as shown in FIGS. 31 and slide part 3
It consists of two. The slide portion 32 is provided on the first fixing member 1.
It is fixed to the first and second fixing members 12 and slides with respect to the shaft 31 so that the gap between the first fixing member 11 and the second fixing member 12 can be freely changed.

<F> Arrangement of Optical Fiber The optical fiber 4 is stretched between the first mounting member and the second mounting member to form a tension portion 41. The tension portion 41 generates tension in accordance with a change in the gap between the first fixing member 11 and the second fixing member 12. When the optical fiber 4 is wound around a rotatable bobbin 211 as shown in FIGS. 2 and 3, tension can be evenly applied to the plurality of optical fibers 211. An optical fiber is connected in series with the optical fiber of the tension part 41, and the correction part 42 of the optical fiber is arranged near the tension part 41.

<D> Measurement by Displacement Sensor As shown in FIG. 4, the detection device 5 is connected to one end of the optical fiber 4, sends out an optical signal, and receives a reflected wave returned from the optical fiber 4. As shown in FIG. 5, it is possible to measure a specific portion of the optical fiber 4, that is, the tension of the tension portion 41 and the correction portion. Even if a plurality of displacement sensors are connected in series, the displacement sensor can be specified from the position where the tension is measured.

When the object to be measured is distorted, the gap between the first fixing member 11 and the second fixing member 12 of the displacement sensor fixed thereto changes, and accordingly, tension is generated in the optical fiber 4 of the tension portion 41. I do. The detecting device 5 can measure the tension value of the optical fiber 4 and its position. As a result, the displacement sensor can be specified, and the value of the displacement of the measured object can be obtained. The detecting device 5 can be a device that measures the tension of an optical fiber. For example, a B-OTDR measuring device (AQ8
602, manufactured by Ando Electric Co., Ltd.).

When the temperature of the displacement sensor changes, the tension of the optical fiber 4 of the tension portion 41 changes, and the measured value of the displacement sensor also changes. Since the tension of the optical fiber 4 of the correction unit 42 also changes, the correction unit 42 can correct the tension value of the tension unit 41 from the measured value, and can correct the temperature of the measurement value of the displacement sensor.

Note that the length of the tension portion 41 and the number of optical fibers 5 change depending on the performance of the detection device 5, and accordingly, the size of the displacement sensor can also change. Further, by providing the displacement sensor with a waterproof case, the displacement sensor can be used in any place such as a place where groundwater is generated.

[0017]

According to the present invention, the following effects can be obtained. <A> A displacement sensor can be obtained by effectively utilizing the characteristics of the optical fiber. <B> A displacement sensor that does not require a power supply can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view of a displacement sensor using an optical fiber.

FIG. 2 is a plan view of a displacement sensor.

FIG. 3 is a side view of a displacement sensor.

FIG. 4 Arrangement of optical fibers

FIG. 5 is a diagram showing the tension of an optical fiber.

[Explanation of symbols]

 11, first fixing member 112, fixing bracket 12, second fixing member 21, first mounting member 211, bobbin 212, bobbin nut 22, second mounting member 3, holding member 31, shaft 32,・ Slide part 4 ・ ・ ・ Tension 41 ・ ・ Tension part 42 ・ ・ Correction part 5 ・ ・ ・ Detector

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Ichiro Okubo 5-15-18 Higashikashigaya, Ebina-shi, Kanagawa F-term in Toyoko Hermes Co., Ltd. 2F065 AA02 AA09 AA65 CC00 EE01 FF41 LL02

Claims (5)

[Claims] A first fixing member fixed to an object to be measured;
A fixing member, a first attaching member attached to the first fixing member, a second attaching member attached to the second fixing member, and a gap between the first attaching member and the second attaching member displacing the object to be measured. A holding member for holding the first mounting member and the second mounting member so as to change in accordance with the condition, and an optical fiber stretched between the first mounting member and the second mounting member, and measuring the tension of the optical fiber. And a displacement sensor for determining a displacement of an object to be measured. 2. The displacement sensor according to claim 1, wherein the first mounting member is rotatable with respect to the first fixing member.
A second mounting member rotatable with respect to the second fixing member;
A displacement sensor comprising a bobbin. 3. The displacement sensor according to claim 2, wherein each of the first bobbin and the second bobbin comprises a plurality of independently rotating bobbins, and a plurality of bobbins between the first bobbin and the second bobbin. A displacement sensor, wherein an optical fiber is arranged. 4. The displacement sensor according to claim 1, wherein the holding member is formed of a shaft and slidably holds the first fixing member and the second fixing member. 5. The displacement sensor according to claim 1, wherein the displacement sensor is connected in series with an optical fiber stretched between the first holding member and the second holding member, and is disposed near the optical fiber without applying tension. A displacement sensor, comprising: