JP2018040680A - Moving amount measurement system and displacement gauge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a moving amount measurement system and a displacement gauge which are capable of inexpensively and accurately measuring the amount of movement of a body.SOLUTION: A rotation measuring apparatus includes: a rotating body; a linear motion body 25 that is connected to the rotating body via a mechanism for converting rotation of the rotating body into vertical linear motion, so as to reciprocatively and linearly move; a magnetic body attached to a tip of the linear motion body 25; and a light intensity detector 27A for detecting a change in magnetic field due to movement of the magnetic body as a change in light intensity of an optical signal. The light intensity detector 27A is an optical sensor having a Faraday element. The optical sensor is connected to each of a transmitter and a receiver via optical cables 16A and 16B. A moving amount measurement system: counts the number of revolutions of the rotating body of the rotation measuring apparatus, by counting means connected to the receiver, on the basis of a change in light intensity of a signal received by the receiver; obtains the number of revolutions of a wound body 22 on the basis of the number of revolutions of the rotating body; and measures the amount of movement of a body B on the basis of the number of revolutions of the wound body 22 obtained by the counting means.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a movement amount measurement system and a displacement meter for measuring a movement amount of an object.

  When measuring the amount of movement of an object under various circumstances, a system and a displacement meter capable of measuring an accurate amount of movement with a simple configuration are required. For example, in order to detect the scouring condition of the ground, a method of detecting the state of the riverbed from the air with an optical or ultrasonic sensor is known as a detection unit. The light and ultrasonic waves are obstructed by the turbid flow and the accurate distance cannot be detected.

  Therefore, for example, Patent Document 1 and Patent Document 2 propose a method in which a plurality of sensors are embedded in the riverbed (ground) and the riverbed is scoured and the sensors are directly exposed to the water flow. Sensors detect the presence or absence of scouring, embed a plurality of sensors at positions spaced in the vertical direction, set the depth of each sensor in advance, and expose by scouring The depth of the scouring can be detected by the sensor.

  In Patent Document 1, the detection unit main body is erected with the lower half of the detection unit main body extending in the vertical direction embedded in the ground. In the lower half of the detection unit main body, a plurality of sensitive parts are arranged at intervals in the vertical direction. Inside the lower half, AE (acoustics) are located at positions corresponding to the sensitive parts.・ Emission sensor is installed. The AE sensor detects an ultrasonic wave generated by friction of the sensitive part exposed by scouring the ground with river water.

  Further, in Patent Document 2, a plurality of sensors having a light emitting part and a light receiving part which are connected to an optical fiber and face each other are embedded in the ground with being attached to a bridge pier. In the sensor, when the earth and sand between the light emitting unit and the light receiving unit are absent due to scouring of the ground, the light receiving unit detects the laser light from the light emitting unit.

  According to such devices of Patent Document 1 and Patent Document 2, the depth of scouring can be measured, but in order to measure the depth of scouring, a plurality of sensors are installed at intervals in the vertical direction. There is a need. Since the depth detection accuracy depends on the number of sensors, in order to increase the accuracy, it is necessary to reduce the interval and increase the number of sensors. As a result, the installation cost increases.

  In addition, a power source is required to operate the detection unit including the sensor. However, when heavy rain or a typhoon comes, there is a possibility that the electrical function of the detection unit is damaged due to lightning strikes and the detection function does not function. Furthermore, when a bridge is installed in a mountainous area or a backland where the power transmission environment is not maintained, it is difficult to supply power to the detection unit.

  Patent Document 3 discloses a landslide detection system that does not require installation of a large number of sensors and power supply to a detection unit. The landslide detection system detects landslide by an expansion and contraction measuring device having an optical rotation sensor. The rotation sensor includes a disk-shaped rotating body in which a plurality of magnetic bodies (magnets) are arranged in the circumferential direction, and a Faraday proximity sensor fixedly arranged in proximity to the rotating body. When the Faraday proximity sensor detects a change in the magnetic field caused by the rotation, the number of rotations of the rotating body can be obtained. In the expansion / contraction measuring apparatus, the wire winding portion around which the wire is wound rotates with the rotating body of the rotation sensor. In the landslide detection system of Patent Document 3, the tip of a wire is attached to a moving pile embedded in a slope of a mountain. When the moving pile moves due to a landslide and pulls the wire, the wire winding unit rotates and the wire At this time, the rotating body also rotates together with the wire winding unit. Then, when the Faraday proximity sensor detects a change in the magnetic field generated by the rotation of the rotating body, the number of rotations of the rotating body and the amount of movement of the moving pile can be obtained.

  If such a landslide detection system configuration is applied to a scour detection system, an increase in cost due to the installation of a large number of sensors can be avoided, and it is not necessary to supply power to the detection unit.

JP-A-11-271057 JP-A-11-271058 JP2009-128022A

  However, the rotation sensor of Patent Document 3 is configured to detect a change in the magnetic field caused by the movement of a rotating body in which a plurality of magnetic bodies are arranged in the circumferential direction with the Faraday proximity sensor. Depending on the performance (sensitivity, reaction speed, etc.), there is a possibility that a change in the magnetic field cannot be detected accurately. In addition, since the strength of the magnetic field changes depending on the installation environment of the rotation sensor (for example, the ambient temperature), the strength of the magnetic field does not become constant even if the magnetic body moves on a predetermined trajectory when the rotating body rotates. There is a risk that changes in the magnetic field cannot be accurately detected. Thus, when the change of a magnetic field cannot be detected correctly, even if the structure of the landslide detection system of patent document 3 is applied to a scour detection system, an exact scour depth cannot be obtained.

  In view of such circumstances, it is an object of the present invention to provide a movement amount measuring system and a displacement meter that can reduce costs and measure an accurate movement amount without using a plurality of sensors. To do.

  According to the present invention, the above-described problem is solved by the movement amount measuring system according to the first invention and the displacement meter according to the second invention.

<First invention>
The movement amount measurement system according to the present invention measures the movement amount of an object.

  In such a moving amount measuring system, in the present invention, a wound body around which a tension transmission member is wound and rotatable around an axis, the tension transmission member connecting the wound body and the object, and the wound body A rotation amount measuring device that measures the amount of rotation of the light, a transmission device that transmits an optical signal from the light source to the rotation amount measurement device as a transmission signal, a reception device that receives an optical signal from the rotation amount measurement device as a reception signal, An optical fiber cable serving as a communication path for optical signals, and the rotation amount measuring device is connected to the rotating body via a rotating body and a mechanism that converts the rotation of the rotating body into a linear motion in the vertical direction. A linear motion body that moves, a magnetic body attached to the tip of the linear motion body, and a change in the magnetic field that accompanies the movement of the magnetic body is detected as a change in the light intensity of the optical signal. A light intensity detecting unit for detecting the light intensity. The unit is an optical sensor having a Faraday element, and the optical sensor is connected to each of the transmission device and the reception device via an optical fiber cable, and the reception device receives by the counting means connected to the reception device. The number of rotations of the rotating body of the rotation amount measuring device is counted based on the change in the light intensity of the received signal, and the number of rotations of the wound body is obtained based on the number of rotations of the rotating body. It is characterized in that the amount of movement of the object is measured based on the number of rotations of the wound body.

  In the present invention having such a configuration, the wound body draws out or winds up the tension transmitting member as the object moves. In the rotation amount measuring device, the rotational motion of the rotating body that rotates in accordance with the rotation of the wound body is converted into the reciprocating motion of the movable body in the vertical direction, and accompanying the movement of the magnetic body attached to the tip of the linear motion body The change in the magnetic field is detected by a light intensity detection unit arranged on the axis of the moving direction of the linear motion body. The light intensity detection unit is an optical sensor having a Faraday element (Faraday element sensor), and when a magnetic field changes when a magnetic substance approaches or separates from the Faraday element sensor, an output signal from the Faraday element sensor is output. Since the light intensity changes, the number of reciprocations of the linear motion body and the rotation amount of the rotating body can be obtained from the change in the light intensity based on the number of times the magnetic body approaches or separates, and further the rotation amount of the rotating body is obtained. A quantity is obtained. Then, the feeding amount or winding amount of the tension transmission member is calculated from the rotation amount of the wound body and the winding diameter of the tension transmission member, and the movement amount of the object is measured. Thus, in the present invention, only one Faraday element sensor is provided in the rotation amount measuring device.

  Further, since the Faraday element sensor is always located on the axis of the reciprocating direction (vertical direction) of the magnetic material, it is possible to continuously measure the change of the magnetic field accompanying the reciprocating motion of the magnetic material, and to approach or separate the magnetic material. Can be reliably detected. That is, in the present invention, the rotation amount of the rotating body and the rotation amount of the wound body can be obtained with higher accuracy than the conventional case where the sensor detects the passage of the magnetic body that rotates and moves together with the rotating body. .

  Furthermore, since the Faraday element sensor is only connected to an optical fiber cable, it does not use electrical components, does not require a power source (equipment), and is not susceptible to lightning strikes such as lightning strikes. Thus, since a power supply (equipment) is not required for the Faraday element sensor, it is possible to reduce the initial cost of construction and the running cost of application.

  In addition, since the Faraday element sensor and the optical fiber cable are merely optically connected, there are no mechanical parts, so that even if they are used for a long period of time, the possibility of failure is low and the stability is high.

  Furthermore, in the present invention, a base station in which a transmission device, a reception device, a control device, an analysis device, etc. for communicating an optical signal with an optical fiber cable is placed from an object (movement amount measurement target) to several kilometers to several tens. It can be installed in a remote place separated by km, and the degree of freedom of operation of the detection system is improved.

  In the present invention, the receiving device has a first receiver and a second receiver, and the optical fiber cable has a transmission path for communicating the transmission signal and a reception path for communicating the reception signal. The receiving path is branched into a first branch receiving path connected to the first receiver and a second branch receiving path connected to the second receiving path. At least one can be adjusted by increasing or decreasing the light intensity of the received signal from the rotation amount measuring device by a predetermined amount, and the first receiver receives the received signal communicated through the first branch receiving path, The second receiver receives a reception signal communicated on the second branch reception path, and the counting means receives both the reception signal received by the first receiver and the reception signal received by the second receiver. Rotates when the light intensity of the signal satisfies a predetermined condition regarding the light intensity The number of rotation may be is configured to count.

  In the present invention, a threshold is set in advance for the light intensity of the output signal (reception signal) from the Faraday element sensor as the light intensity detector. For example, the light intensity of the reception signal from the Faraday element sensor is the above threshold value. When the value exceeds or falls below, the counting means counts the number of rotations of the rotating body.

  By the way, the output signal from the Faraday element sensor may cause so-called chattering in which the light intensity fluctuates finely so as to cross the threshold value. When the chattering occurs, the light intensity of the received signal exceeds or falls below the threshold value a plurality of times. For example, even though the rotating body rotates only once, the counting means sets the number of rotations for a plurality of times. There is a risk of counting.

  In the present invention, since the light intensity of the reception signal from the rotation amount measuring device is adjusted at least one of the first branch reception path and the second branch reception path, the first reception signal received by the first receiver The light intensity is different from that of the second received signal received by the second receiver. As a result, when chattering occurs, the first receiver and the second receiver receive the chattered received signals at different timings. Therefore, a predetermined condition is set for the light intensities of both reception signals, and the counting means counts the number of rotations of the rotating body only when both the reception signals satisfy the predetermined condition. Then, even if chattering occurs, it is possible to reliably count the number of rotations of the rotating body only once, and it is possible to improve the accuracy of measurement of the amount of rotation of the wound body and thus the amount of movement of the object.

<Second invention>
The displacement meter according to the present invention measures the amount of rotation of a wound body that is wound around a tension transmission member and is rotatable about an axis.

  In such a displacement meter, in the present invention, the rotation amount detection device includes a rotating body, a linear moving body that is connected to the rotating body via a mechanism that converts the rotation of the rotating body into a linear motion in the vertical direction, and that reciprocates linearly. A magnetic body attached to the tip of the linear motion body, and a light intensity detection unit that is arranged on the axis of the motion direction of the linear motion body and detects a change in the magnetic field accompanying the movement of the magnetic body as a change in the light intensity of the optical signal The light intensity detector is an optical sensor having a Faraday element.

  As described above, according to the present invention, as the object moves, the wound body feeds or winds the tension transmission member, and the feed amount or the take-up amount is measured by the rotation amount measuring device or the displacement meter. The amount of movement of the object is measured by obtaining from the amount of rotation of the rotating body, and when the object moves, the amount of extension of the tension transmitting member or the amount of winding of the tension transmitting member is determined from the amount of rotation of the wound body and the winding diameter of the tension transmitting member. Since the amount of movement can be calculated and the amount of movement of the object can be measured, it is economically advantageous because only one rotation sensor or displacement sensor is required, and the amount of movement of the object can be measured continuously. You can know the amount of movement accurately.

1 is a schematic configuration diagram mainly showing a ground scour monitoring device in a scour detection system as an embodiment of a movement measuring system according to the present invention. It is a schematic block diagram which shows the part located in a bridge among the scour detection systems of FIG. The structure of the rotation amount measuring device provided in the inside of the detection box part seen by FIG. 2 is shown, (A) is a front view, (B) is a side view. (A) thru | or (C) is a figure which shows a series of operation | movement of a rotation amount measuring device. It is a block diagram which shows the internal structure of the detection unit of a ground scour monitoring apparatus. It is a schematic block diagram of the structure schematic diagram of the movement amount measuring system which concerns on the modification of this invention, (A) is the intrusion monitoring system which concerns on a 1st modification, (B) is the landslide monitoring which concerns on a 2nd modification. System (C) shows a water level monitoring system according to a third modification.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic configuration diagram of the apparatus of the present embodiment as a scour detection system, and FIG. 2 is a diagram showing a detection portion on the distal end side of the optical fiber cable of each detection unit of FIG.

  As shown in FIG. 1, the present embodiment has a ground scour monitoring device 10 as a monitoring base station installed in a station building, a security zone, etc., and the ground scour monitoring device 10 transmits light. Then, the scouring depth is obtained from a large number of detection units 11 (only four detection units 11A, 11B, 11C, and 11D are shown in FIG. 1) as optical transmission / reception devices to be received and signal information from each detection unit. It has the depth conversion apparatus 12, the control apparatus 13 which determines the output from the depth conversion apparatus 12 while controlling these, and the display apparatus 14 which displays the result. The control device 13 is connected to a wireless communication device 15 that communicates with the train T or the like.

  Optical fiber cables 16A, 16B, 16C, and 16D (collectively referred to as “optical fiber cable 16” as necessary) extend from each of the detection units 11A, 11B, 11C, and 11D. 16B, 16C, and 16D are gathered as one main cable 17 as a preferable form, and extend toward the position of a bridge of a river or the like where ground scouring should be detected, and their tips are light beams using a Faraday element. It is connected to Faraday proximity sensors 27A, 27B, 27C, and 27D as sensors (Faraday element sensors). As described above, since a large number of the detection units 11 are provided, the corresponding number of optical fiber cables 16 are inserted into one trunk cable 17.

  As shown in FIG. 1, each of the optical fiber cables 16A to 16D sequentially drawn from one trunk cable 17 is positioned at a plurality of bridge supports B2 that support the bridge body B1 of the bridge B as shown in FIG. (Only the optical fiber cables 16A and 16B are shown in FIG. 2). FIG. 2 shows Faraday proximity sensors 27A and 27B to which the ends of the optical fiber cables 16A and 16B are connected. Further, instead of inserting a plurality of optical fiber cables 16 into the main cable 17, for example, an optical fiber in which a plurality of optical fibers are accommodated in the main cable 17 and the optical fibers are inserted into a metal tube. The cable 16 may be branched from the trunk cable 17 to each bridge support B2.

  As shown in FIG. 2, the bridge B is, for example, a railway bridge, and a bridge body B1 located above the river and a bridge that stands on the ground of the river and forms a column that supports the bridge body B1 at the upper end thereof. The detection box 20 is supported at the corner formed by both the bridge body B1 and the bridge support B2. The detection box 20 can be supported by either the bridge body B1 or the bridge support B2.

  As described above, the ends of the optical fiber cables 16A, 16B, 16C, and 16D extending from the detection units 11A, 11B, 11C, and 11D are connected to the Faraday proximity sensors 27A, 27B, 27C, and 27D. Although the fiber cables 16A, 16B, 16C, and 16D extend to the corresponding bridge support B2 of the bridge B, only two optical fiber cables 16A and 16B are illustrated in FIG. Since the detection boxes 20 into which the ends of the two optical fiber cables 16A and 16B are introduced have the same internal configuration, the detection box 20 into which the optical fiber cable 16A is introduced will be described below.

  In the detection box 20, as shown in FIGS. 3A and 3B, a wire 22 as a tension transmission member is wound and the drum 22 as a wound body rotatably supported, and the drum A rotation amount measuring device 23 as a displacement meter for measuring the rotation amount 22 is provided. The rotation amount measuring device 23 is connected to the rotating body 24 through a rotating body 24 that rotates together with the drum 22 and a mechanism that converts the rotation of the rotating body 24 into a linear motion in the vertical direction. The moving body 25, the magnetic body 26 attached to the lower end of the linear moving body 25, and the magnetic field change caused by the movement of the magnetic body 26 arranged on the axis of movement of the linear moving body 25 (vertical direction) And a Faraday proximity sensor 27 as a light intensity detection unit that detects a change in light intensity.

  A wire 21 is wound around the drum 22, one end serving as a winding start end is not fixed to the drum 22, and the other end extends out of the detection box 20 from the drum 22. As can be seen, a hanging rod 18 as a weight is attached. The drooping bar 18 is a bar-like member extending in the vertical direction along the bridge support B2, and its lower end is located on the upper surface (ground surface) P1 of the ground P serving as the riverbed. The hanging bar 18 is merely located on the ground surface P1, and is not embedded in the ground. As a material of the hanging rod 18, for example, concrete or steel can be used. The drooping bar 18 may be supported so as to be movable in the vertical direction by a supporting member (not shown) attached to the side surface of the bridge support B2. For example, the support member can be formed of a ring-shaped member, and the hanging rod 18 can be inserted through the ring-shaped member in a free state. In this way, the drooping rod 18 is not caused to flow, vibrate, or be damaged due to an increase in the flow rate such as turbid flow or contact with floating substances such as driftwood.

  As shown in FIG. 3A, the drum 22 has a body portion 22A, flange portions 22B-1, 22B-2, and shaft portions 22C-1, 22C-2, and is installed in the detection box 20. The bearings 31A and 31B housed in the bearing housing portions 30A and 30B are rotatably supported. Shaft portions 22C-1 and 22C-2 projecting from flange portions 22B-1 and 22B-2 provided at both ends of the drum 22 are respectively supported by corresponding bearings 31A and 31B.

  In the drum 22, the wire 21 is wound around the body portion 22 </ b> A. As described above, one end serving as a winding start end is not fixed to the drum 22, and the other end hangs down from the drum 22. It hangs through the window portion 20A formed on the wall and hangs down from the bottom wall.

  In this embodiment, since the winding start end of the wire 21 is not fixed to the drum 22, not only the drooping bar 18 sinks by scouring due to typhoon or flood, but also when the drooping bar 18 is flown, the wire 21 Since the wire 21 comes out of the drum 22 after it has been fed out from the drum 22, there is no possibility that the drum 22 is pulled by the wire 21 and damaged. Thus, the drum 22 is prevented from being damaged.

  Moreover, since it is only necessary to rewind the wire 21 around the drum 22 at the time of restoration, there is no need to re-install the drum 22, thereby reducing costs and shortening the restoration time.

  One shaft portion 22C-2 of the drum 22 protrudes from the corresponding bearing 31B, and a rotating body 24 is attached to the tip thereof so that the rotating body 24 rotates integrally with the shaft portion 22C-2. It has become. As seen in FIG. 3B, the rotating body 24 has an engaging protrusion 24A that protrudes from the outer peripheral surface thereof. 3B, the linear motion body 25 is adjacent to the rotary body 24 on the side of the rotary body 24, and accommodates the movable member 28 in the form of a bar extending in the vertical direction. And a tubular housing member 29 that is supported so as to be linearly movable in the vertical direction. The movable member 28 has an engaged protrusion 28 </ b> A that protrudes from the side surface toward the rotating body 24. A magnetic body 26 such as a magnet is attached to the lower end of the movable member 28. The accommodating member 29 is formed with a slit-shaped guide groove (not shown) that guides the engaged protrusion 28A of the movable member 28 that moves linearly. As shown in FIG. 3B, the engaged protrusion 28A penetrates the guide groove and protrudes from the side surface of the housing member, and can be engaged with the engaging protrusion 24A of the rotating body 24 as described later. (See FIGS. 4A to 4C).

  A Faraday proximity sensor 27 </ b> A is disposed immediately below the movable member 28 and is supported by a support body 32 attached to the bottom wall of the detection box 20. An optical fiber cable 16A extends out of the detection box 20 from the Faraday proximity sensor 27A. Since the Faraday element has a characteristic of changing the intensity of reflected light by rotating the plane of polarization of linearly polarized light according to the strength of the magnetic field, in the Faraday proximity sensor 27A using this Faraday element, as will be described later, It is detected as a change in the light intensity of the optical signal due to the fluctuation of the magnetic field accompanying the reciprocation of the magnetic body 26.

  As shown in FIG. 4A, when the wire 21 wound around the drum 22 is fed and the drum rotates counterclockwise, the rotating body 24 also rotates counterclockwise together with the drum 22. When the rotating body 24 starts to rotate, the engaging protrusion 24A of the rotating body 24 comes into contact with the engaged protrusion 28A of the movable member 28 of the linear moving body 25 from below as seen in FIG. By engaging, the movable member 28 that was originally in the lowest position (position in FIG. 4A) moves upward and is brought to the uppermost position (position in FIG. 4B). As shown in FIG. 4C, when the rotating body 24 further rotates and the engaging protrusion 24A passes the position of the engaged protrusion 28A, the engagement protrusion 24A and the engaged protrusion 28A are engaged. The combined state is released, and the movable member 28 freely falls and returns to the lowest position. In this way, each time the drum 22 and thus the rotating body 24 rotate once, the movable member 28 of the linear moving body 25 reciprocates once between the lowermost position and the uppermost position.

  The Faraday proximity sensor 27A is closest when the movable member 28 is at the lowest position as seen in FIGS. 4A and 4C. As shown in FIG. It is farthest away in the uppermost position. In the Faraday proximity sensor 27A, a change in the magnetic field generated when the magnetic body 26 approaches or separates from the Faraday proximity sensor 27A as the movable member 28 reciprocates in the vertical direction is regarded as a change in the light intensity of the optical signal. Detect. This change in light intensity is obtained as a sinusoidal signal that changes over time with a constant amplitude and period.

  As will be described later, the number of reciprocating motions of the linear motion body 25 and the rotation of the rotating body based on the number of times the magnetic body 26 approaches or separates from the change in the light intensity of the output signal (optical signal) of the Faraday proximity sensor 27A. The amount (number of rotations) is obtained, and further the amount of rotation (number of rotations) of the drum 22 is obtained. In the present embodiment, a predetermined threshold (hereinafter referred to as “light intensity threshold”) for counting the number of rotations of the rotating body 24 is set in advance with respect to the light intensity of the optical signal from the Faraday proximity sensor 27A. The relationship between the number of rotations of the rotating body 24 and the light intensity threshold will be described later.

  Since the Faraday proximity sensor 27A of this embodiment is always located on the axis of the reciprocating direction (vertical direction) of the magnetic body 26, it can continuously measure the change in the magnetic field accompanying the reciprocating movement of the magnetic body 26, The proximity or separation of the body 26 can be reliably detected. That is, in the present invention, the amount of rotation of the rotating body and thus the amount of rotation of the wound body can be obtained with higher accuracy than in the case where the sensor detects the passage of the magnetic body that rotates and moves together with the rotating body. Therefore, for example, according to this embodiment, even when the strength of the magnetic field changes depending on the installation environment (such as the ambient temperature) of the rotation amount measuring device 23, the rotation amount of the wound body can be measured with high accuracy. Can be done.

  In the present embodiment, since the optical fiber cable 16 is connected to the Faraday proximity sensor 27, the supervisory base station where the optical transceiver is installed should be installed at a position several kilometers to several tens kilometers away from the bridge support. Therefore, even if the place where the bridge is installed is in a mountainous area or a remote place, a supervisory base can be installed in a place away from the bridge where the optical transceiver can be easily installed. The status of scouring of the support can be confirmed. In addition, since the Faraday proximity sensor and the optical fiber are only connected in the detection box 20, no electrical components are used, and there is no possibility of being affected by lightning strikes such as lightning strikes. Furthermore, since the Faraday proximity sensor and the optical fiber are merely optically connected, there are no mechanical parts, so that even if they are used for a long period of time, the possibility of failure is low and the stability is high.

  Next, the structure of the detection unit 11 is demonstrated based on FIG. Since the detection units 11A, 11B, 11C, and 11D have the same configuration, the detection unit 11A will be described here. As shown in FIG. 5, the detection unit 11A includes a transmission device 41 that transmits an optical signal from the light source 41A as a transmission signal to the Faraday proximity sensor 27A of the rotation amount measurement device 23, and an optical signal from the Faraday proximity sensor 27A. And a counting device 43 as counting means for counting the number of rotations of the rotating body 24 of the rotation amount measuring device 23 based on a change in the light intensity of the received signal received by the receiving device 42. have. The receiving device 42 includes two receivers 42A and 42B described later.

  The detection unit 11A is connected to the Faraday proximity sensor 27 by an optical fiber cable 16A. The optical fiber cable 16A is branched into two optical fiber cables by a splitter 44 provided in the detection unit 11A, and is connected to a transmission device 41 and a reception device 42, respectively. The optical fiber cable connected to the transmitter 41 is used as a transmission path 45 for communicating a transmission signal from the light source 41A of the transmitter 41, and the optical fiber cable connected to the receiver 42 is a Faraday cable. Used as a reception path 46 for communicating a reception signal from the proximity sensor 27.

  The receiving path 46 is branched by a splitter 47 into a first branch receiving path 46A connected to the first receiver 42A and a second branch receiving path 46B connected to the second receiver 42B. A first attenuator 48A is connected to the first branch receiving path 46A between the splitter 47 and the first receiver 42A, and the first attenuator 48A attenuates the light intensity of the received signal by a predetermined amount. It is like that. A second attenuator 48B is connected to the second branch receiving path 46B between the splitter 47 and the second receiver 42B. The second attenuator 48B reduces the light intensity of the received signal by a predetermined amount. It is designed to attenuate. In the present embodiment, the attenuation amount of the light intensity at the second attenuator 48B is larger than the attenuation amount of the light intensity at the first attenuator 48A. That is, the received signal (hereinafter referred to as “second attenuated received signal”) received by the second receiver 42B is more than the received signal received by the first receiver 42A (hereinafter referred to as “first attenuated received signal”). Low light intensity.

  The counting device 43 is connected to both the first receiver 42A and the second receiver 42B, and both the light intensity of the first attenuated received signal and the light intensity of the second attenuated received signal are the light intensity described above. When the threshold value, that is, the light intensity of the optical signal from the Faraday proximity sensor 27A falls below a predetermined threshold value set in advance, the number of rotations of the rotating body 24 is counted only once. As can be seen in FIG. 5, the depth conversion device 12 is connected to the counting device 43, and the depth conversion device 12 is rotated by the rotational speed of the rotating body 24 counted by the counting device 43 as will be described later. Measure scouring depth based on

  The present embodiment apparatus configured as described above measures the scouring depth in the following manner. First, when the ground P is scoured at the base position of the bridge support B2 of the bridge B due to the increase of the river, the ground P is locally sunk, so that it is indicated by a two-dot chain line in FIG. Thus, the drooping rod 18 located on the ground surface P1 is lowered by the scouring depth by its own weight. That is, the wire 21 is fed by the amount of the drop of the drooping bar 18, and the drum 22 is rotated accordingly. As the drum 22 rotates, the rotating body 24 attached to the shaft portion 22C-2 of the drum 22 also rotates by the same amount as the drum 22.

  As described above, the rotation of the rotating body 24 is converted into the reciprocating motion of the movable member 28 of the linear moving body 25 in the vertical direction, and the magnetic body 26 of the movable member 28 approaches or separates from the Faraday proximity sensor 27A. The Faraday proximity sensor 27A detects a change in the magnetic field that sometimes occurs as a change in the light intensity of the optical signal.

  The output signal (reception signal) from the Faraday proximity sensor 27A propagates through the optical fiber cable 16A and the reception path 46, and then propagates through each of the first branch reception path 46A and the second branch reception path 46B branched by the splitter 47. . As described above, the received signal propagating through the first branch receiving path 46A is attenuated by the first attenuator 48A, and the received signal propagating through the second branch receiving path 46B is attenuated by the second attenuator 48B. The first attenuated received signal and the second attenuated received signal have different light intensities. In the present embodiment, as described above, the light intensity of the second attenuated received signal is smaller than the light intensity of the first attenuated received signal.

  In the present embodiment, the attenuation amount of the light intensity by the second attenuator 48B is larger than the attenuation amount of the light intensity by the first attenuator 48A, and the light of the second received signal received by the second receiver 42B. The intensity is smaller than the light intensity of the first received signal received by the first receiver 42A. Therefore, the second attenuated received signal falls below the above-described light intensity threshold earlier than the first attenuated received signal. That is, even if only the second attenuated reception signal is below the light intensity threshold, the counting device 43 does not count the number of rotations of the rotating body 24 when the first attenuated reception signal is not yet below the light intensity threshold. And when time passes further and the 1st attenuation | damping reception signal also falls below a light intensity threshold value, the rotation speed of the rotary body 24 is counted only once for the first time.

  In this embodiment, if chattering occurs in the reception signal (output signal) from the Faraday proximity sensor 27A, the second attenuation in the chattering state of the second receiver 42B is earlier than that of the first receiver 42A. Receive a received signal. The light intensity of the received signal in the chattering state falls below the light intensity threshold value a plurality of times even though the rotating body 24 rotates only once. However, when the second receiver 42B receives the second attenuated reception signal in the chattering state, the counting device 43 does not yet receive the first attenuated reception signal in the chattering state. The number of rotations of the rotating body 24 is not counted. Then, when the first receiver 42A receives the first attenuated reception signal in the chattering state and the light intensity falls below the light intensity threshold, the number of rotations of the rotating body 24 is counted only once. Therefore, in this embodiment, even if chattering occurs, the counting device 43 does not mistakenly count the number of rotations for a plurality of times, and the number of rotations can be reliably counted only once. It is possible to improve the accuracy of measuring the amount of rotation and thus the scouring depth of the ground.

  In the present embodiment, the attenuation amount of the light intensity at the first attenuator 48A and the attenuation amount of the light intensity at the second attenuator 48B are the chattering period and the second attenuation reception signal in the first attenuation reception signal. The amount of attenuation having a sufficient difference is set in advance so that the chattering period in FIG. Therefore, it is avoided that both the first attenuator 48A and the second attenuator 48B simultaneously receive the attenuated reception signal in the chattering state, and the rotational speed of the rotating body 24 can be counted more accurately.

  An output signal from the counting device 43, that is, a signal indicating the number of rotations of the rotating body 24 is sent to the depth conversion device 12. The depth conversion device 12 measures the scouring depth by converting the number of rotations from the diameter of the drum 22 and the winding diameter of the wire 21 to the feeding length of the wire 21. Further, a signal indicating the scouring depth is sent from the depth conversion device 12 to the control device 13. Then, when the control device 13 compares the calculated scouring depth with an allowable value indicating a preset danger depth and determines that it is in a dangerous state exceeding the allowable value, the determination result is displayed on the display device 14. Is displayed. Moreover, the radio | wireless communication apparatus 15 can transmit the radio signal corresponding to the said determination result toward the train T or a security area, and can notify the crew member of this train T. As a result, accidents can be prevented by stopping the train T as appropriate.

  In the present embodiment, the condition that the counting device counts the number of rotations of the rotating body is that the reception signals of both the first attenuation reception signal and the second attenuation reception signal fall below the light intensity threshold. Instead, for example, the condition may be that both the first attenuated received signal and the second attenuated received signal exceed the light intensity threshold.

  In the present embodiment, the received signals are attenuated by providing the attenuators 48A and 48B in the branch receiving paths 46A and 46B, respectively, but instead, for example, they are different from each other without providing an attenuator. Each of the branch receiving paths 46A and 46B may be formed by connecting optical fiber cables having reflectivity, and the received signal may be attenuated at a connection point between the optical fiber cables.

  In the present embodiment, both the reception signal received by the first receiver 42A and the reception signal received by the second receiver 42B are attenuated. Instead, either one of them is attenuated. Only the received signal may be attenuated. That is, it is only necessary that the received signal received by the first receiver 42A and the second receiver 42B have different optical intensities.

  In the present embodiment, an example in which a plurality of detection units are provided corresponding to each of the optical fiber cables reaching the detection boxes of a plurality of bridge supports has been illustrated, but each of the optical fiber cables is not provided with a plurality of detection units. Alternatively, only one common detection unit may be provided, and the common detection unit may be sequentially switched and connected to each optical fiber cable. In this way, the cost can be greatly reduced with respect to providing the detection unit.

  In the present embodiment, the example in which the present invention is applied to the scour detection system for obtaining the scour depth of the ground such as the river has been described. However, the present invention is not limited to the example shown in the present embodiment, and the movement is performed. Various modifications for measuring the amount of movement of the moving object are possible. At this time, for example, the rotation amount of a wound body that is wound around a tension transmission member and is rotatable around the axis line, such as the rotation amount measuring device 23 (see FIG. 3A) of the above-described embodiment, is measured. Each modification is possible by using a displacement meter.

  In the first modification, the present invention is applied to an intrusion monitoring system for monitoring an intrusion into a site or the like partitioned by a fence or the like. FIG. 6A is a schematic diagram of an intrusion monitoring system according to the first modification. The displacement meter 240 is provided below the fence F. One end side portion of the wire 221 serving as a tension transmission member wound around a wound body (not shown) of the displacement meter 240 is pulled out from the wound body and then extended in the lateral direction, and then the turning roller 251. At the upper edge of the fence F. In the first modification, the displacement meter 240 has a mechanism (not shown) that biases the wound body in a direction in which the wound body winds the wire 221 (hereinafter referred to as “winding direction”). A slight tension is always applied to the wire 221 so that the one end side portion of the wire 221 does not loosen.

  When the intruder tries to get over the fence F, the upper edge of the fence F bends downward by the height h as shown in FIG. As a result, the wound body rotates in the winding direction, and the wire 221 is wound around the wound body by a length corresponding to the deflection amount (movement amount) of the upper edge of the fence F. The amount of rotation of the wound body is measured by the displacement meter 240 in the same manner as in the embodiment. Then, an intrusion monitoring device (not shown) connected to the displacement meter 240 by an optical fiber cable (not shown) determines the amount of rotation of the wound body as the amount of winding of the wire 221 and the amount of deflection of the upper edge of the fence. The amount of deflection can be measured by converting to. For example, when the converted deflection amount is larger than a predetermined amount, the intrusion monitoring device can detect that an intrusion has occurred in the site and issue an alarm or the like.

  In the second modification, the present invention is applied to a landslide monitoring system for monitoring the occurrence of a landslide on a slope such as a mountain. FIG. 6B is a schematic diagram of a landslide monitoring system according to the second modification. The displacement meter 340 is provided on the upper surface of the slope, and from the displacement meter 340, one end side portion of the wire 321 as a tension transmission member extends downward along the slope. A weight 325 is attached to one end of the wire 321, and the weight 325 is disposed on the slope.

  When a landslide occurs on the slope, the weight 325 moves downward together with the earth or sand, or moves down due to the weight of the weight 325 due to the collapse of the earth and sand, and the wound body (not shown) rotates to move from the wound body. The wire 321 is fed out. As a result, the amount of rotation of the wound body is measured by the displacement meter 340 in the same manner as in the above-described embodiment. Then, a landslide monitoring device (not shown) connected to the displacement meter 340 by an optical fiber cable (not shown) determines the amount of rotation of the wound body by the amount of feeding (length) of the wire 321 and the amount of movement of the weight 325. The amount of movement can be measured by converting to. For example, the landslide monitoring device may detect that a landslide has occurred and issue an alarm or the like when the converted movement amount is larger than a predetermined movement amount.

  In the third modification, the present invention is applied to a water level monitoring system that monitors the position of a water surface such as a river (hereinafter simply referred to as “water level”). FIG. 6C is a schematic diagram of a water level monitoring system according to the third modification. The displacement meter 440 is installed on a riverbed or the like. One end side portion of the wire 421 that is wound around a wound body (not shown) of the displacement meter 440 as a tension transmitting member extends upward, and then changes laterally and downward by the turning rollers 451 and 452. Directed and drooping towards the surface of the water. A float 425 is attached to one end of the wire 421, and the float 425 floats on the water surface. In the third modified example, as in the first modified example described above, the displacement meter 440 has a mechanism (not shown) that rotates the wound body in the winding direction of the wire 421 (winding direction). ), And tension is always applied to the wire 421 so that the one end side portion of the wire 421 does not loosen.

  When the water level of the river rises, the position of the float 425 also rises, so that the winding body rotates in the winding direction, and the wire 421 moves to the winding body by a length corresponding to the rising amount of the float 425. It is wound up. As a result, the amount of rotation of the wound body is measured by the displacement meter 440 in the same manner as the first modification described above. Then, a water level monitoring device (not shown) connected to the displacement meter 440 by an optical fiber cable (not shown) converts the amount of rotation of the wound body into the amount of winding of the wire 421 and hence the float 425 and the amount of rise in the water level. The amount of increase can be measured by conversion. For example, the water level monitoring device may issue an alarm or the like when the converted increase amount is larger than a predetermined amount.

  In addition, when the water level of the river is lowered, the position of the float 425 is also lowered, so that the wound body rotates and the wire 421 is fed out from the wound body. As a result, the amount of rotation of the wound body is measured by the displacement meter 440 in the same manner as in the above-described embodiment. Then, the water level monitoring device connected to the displacement meter 440 by an optical fiber cable converts the amount of rotation of the wound body into the amount of feeding (length) of the wire 421, the float 425, and the amount of descending water level. The amount can be measured. For example, the water level monitoring device may notify the converted descent amount.

  In the third modification, the example of monitoring the water level of a river or the like has been described. However, according to the water level monitoring device, for example, the rise and fall of the liquid level of the liquid stored in the tank can be monitored. .

11A to 11D Optical transceiver (detection unit)
16A-16D Optical fiber cable 21 Wire (Tension transmission member)
18 Drooping rod (weight)
22 drums
23 Rotation amount measuring device (displacement meter)
24 Rotating body 25 Linear motion body 26 Magnetic body 27A to 27D Faraday proximity sensor (light intensity detection unit)
41 transmitting device 41A light source 42 receiving device 42A first receiver 42B second receiver 43 counting device (counting means)
45 Transmission path 46 Reception path 46A First branch reception path 46B Second branch reception path B Bridge B1 Bridge body B2 Bridge support P Ground P1 Ground surface

Claims (3)

In a system that measures the amount of movement
A wound body in which a tension transmission member is wound and rotatable about an axis, and the tension transmission member connecting the wound body and the object;
A rotation amount measuring device for measuring the rotation amount of the wound body;
A transmission device that transmits an optical signal from the light source to the rotation amount measurement device as a transmission signal;
A receiving device for receiving an optical signal from the rotation amount measuring device as a received signal;
An optical fiber cable serving as an optical signal communication path,
The rotation amount measuring device is attached to a rotating body, a linear moving body that is connected to the rotating body via a mechanism that converts the rotation of the rotating body into a linear motion in the vertical direction, and a reciprocating linear motion body, and a tip of the linear moving body. And a light intensity detector that is disposed on the axis of the moving direction of the linear moving body and detects a change in the magnetic field accompanying the movement of the magnetic body as a change in the light intensity of the optical signal,
The light intensity detector is an optical sensor having a Faraday element,
The optical sensor is connected to each of the transmission device and the reception device via an optical fiber cable,
The number of rotations of the rotating body of the rotation amount measuring device is counted based on the change in the light intensity of the received signal received by the receiving device by the counting means connected to the receiving device, and the winding is performed based on the number of rotations of the rotating body. A movement amount measuring system characterized in that the number of rotations of a body is obtained and the amount of movement of an object is measured based on the number of rotations of the wound body obtained by the counting means. The receiving device has a first receiver and a second receiver,
The optical fiber cable has a transmission path for communicating a transmission signal and a reception path for communicating a reception signal,
The receiving path is branched into a first branch receiving path connected to the first receiver and a second branch receiving path connected to the second receiving path,
At least one of the first branch receiving path and the second branch receiving path can be adjusted by increasing or decreasing the light intensity of the received signal from the rotation amount measuring device by a predetermined amount,
The first receiver receives a reception signal communicated on the first branch receiving path,
The second receiver receives a reception signal communicated on the second branch receiving path,
The counting means rotates the rotating body when the light intensity of both the received signal received by the first receiver and the received signal received by the second receiver satisfies a predetermined condition relating to the light intensity. The movement amount measurement system according to claim 1, wherein the movement amount measurement system is set to count the number. In a displacement meter that measures the amount of rotation of a wound body in which a tension transmission member is wound and is rotatable around an axis,
The displacement meter includes a rotating body, a linear moving body that is connected to the rotating body through a mechanism that converts the rotation of the rotating body into a linear motion in the vertical direction, and a magnetic body that is attached to the tip of the linear moving body. A light intensity detector that is disposed on the axis of the body and the moving direction of the linear motion body and detects a change in the magnetic field accompanying the movement of the magnetic body as a change in the light intensity of the optical signal;
The light intensity detector is an optical sensor having a Faraday element.

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