JP4795751B2 - Branch line type ground collapse prediction device - Google Patents

Description

  The present invention predicts in advance the collapse of soft and steep slopes that may cause landslides and unstable rocks that may fall, and minimizes human life and material damage due to falling and collapse. It is invention regarding the structure of the collapse prediction apparatus provided for.

  When earth and sand or rocks that are in danger of collapsing, collapse, partial movement phenomena such as landslides are observed before the collapse phenomenon, and the amount of movement increases at an accelerated rate immediately before the collapse. Is common. The present invention uses a general phenomenon related to such a ground collapse to detect an acceleration displacement of the collapsed portion and to observe the change in the displacement amount, thereby predicting the ground collapse. Concerning structure.

As a specific means of knowing the risk of collapse, the extension detector detects the expansion and contraction of the branch line laid between the alarm device fixed on the stable ground and the unstable ground where there is a risk of collapse. A method is used in which a danger is notified when the amount of displacement of the detected unstable ground exceeds a certain amount within a certain time. An outline of these objects and rough means is as shown in Patent Document 1. However, in order to actually detect and warn of ground collapse, it is difficult to put it into practical use by the method of Patent Document 1 alone, and the present invention overcomes these deficiencies and puts a practical and effective device into practical use. It was made for that purpose.
Japanese Patent Application No. 2004-100016

  The mode of movement of the unstable ground that must be detected for predicting the risk of collapse is not primarily the cumulative amount of steady change but the acceleration of change. For this reason, it is necessary to detect the amount of change within a unit time in the measurement in the detection device that predicts collapse. For example, in the example of Patent Document 1, by manually pressing the reset button every unit time, the opposing switch is moved to the actuator that moves linearly in direct connection with the ground transition, with a fixed time interval, thereby The gap to the switch operating point is kept constant, and the limit of the amount of change within the unit time is set by setting this gap as the allowable movement amount per unit time.

  However, in such a method, there is a practical problem that it is necessary to perform a resetting operation manually every unit time, and it is necessary to operate periodically in a danger area where a danger of collapse is expected. In addition, when performing remote control with an electrical signal, the operation required for the reset operation is required to be a strong and long stroke, so that the power of the motor and its rotational force are converted into reciprocating motion. It required a mechanism and was not practical.

  In the example of Patent Document 1, the linear motion of the actuator that is directly connected to the movement of the unstable ground is directly detected. However, in the present invention, the movement of the combination of the rack gear and the pinion, the operation of the wire winding drum, etc. The linear motion obtained from the movement of the stable ground is converted into rotational motion, and this rotational force is transmitted to the rotation detection plate via the clutch mechanism, and the amount of movement of the ground is detected by the rotation angle of the rotation detection plate. .

  For example, in the displacement detection device of Patent Document 1, since the displacement amount of the collapsed ground is equivalently reproduced inside the detector, in order to improve the detection sensitivity of a minute displacement called ground displacement, A method of enlarging the amount of displacement had to be taken by means such as reciprocating a branch line laid between the collapsed ground and a pulley. In the present invention, since the linear shift is converted into the rotation angle, the shift amount detected as the angle can be arbitrarily enlarged by the method of arbitrarily selecting the rotation diameter on the rotation side in the conversion process. This makes it possible to easily improve detection accuracy without using a method of laying branch lines double.

  The rotation detection plate in which linear displacement is converted into rotational motion is provided with a defect part and a partial non-reflective surface for detecting the rotation angle by a non-contact optical sensor etc. on its circumference, and its center of gravity from the center of rotation. When the clutch mechanism that transmits the rotational force from the rotating shaft is released at the disengaged position, it returns to its natural position so that its center of gravity is located directly under the center of rotation like a pendulum due to its own weight during rotation. A simple reset mechanism could be obtained by adopting a structure that allows automatic recovery by the natural phenomenon of gravity.

  The clutch mechanism is a structure that presses the friction plate with a spring force and transmits the torque of the rotating shaft to the rotation detection plate by the friction force of the friction plate. By reducing the weight of the rotation detection plate, the clutch braking force is reduced. It is possible to set. For the clutch mechanism, a method such as applying a spring pressure to the friction plate is used. As a method for releasing the coupling force of the clutch, the spring pressure pressing the friction plate is pulled back by a suction force such as an electromagnetic solenoid. Such a method is realistic. In any case, the required action force is relatively small and the action stroke is small, and the reset structure is simpler than the case of automating the manual reset mechanism shown in Patent Document 1 by utilizing the natural phenomenon of gravity return. Become practical.

  Since a constant tension is always applied to the branch line laid between the unstable ground and the detection device, the amount of expansion and contraction can be observed as a displacement of the relative distance of the ground without being affected by the slack of the branch line. In the example of Patent Document 1, tension is added to the branch line by the restoring force of the constant tension spring. The constant tension spring used here uses the restoring force of a steel strip quenched to the same radius. Although such a constant tension spring can take a relatively long operating stroke, it has a strong restoring force. Hard to get. On the other hand, the amount of expansion and contraction that can occur in the branch line used in this device is only a minute distance of ground transition, and on the other hand, the wind pressure applied to the branch line, the load of snow that has landed on the snow, and the weight of the stray bird In order to minimize the influence of such loads, it is required that a strong tension be applied.

  The present invention provides the above

In order to properly apply the characteristics of the constant tension spring as described in (1) to this apparatus, the force of the constant tension spring is not directly applied to the branch line, but the power is transmitted via a moving pulley or a different diameter drum, Instead of halving the length of the operation stroke, the acting force is doubled, and the acting force is used as the tension of the branch line. In addition, although the example of acting force multiplication is shown as Example 1, the number of a moving pulley can also be increased as needed, and in the structural example in Example 2, the diameter ratio of a different diameter wire winding drum is arbitrarily selected. By doing so, the amplification ratio of the acting force can be arbitrarily selected.

  When the displacement detection device according to the present invention is laid at an actual collapse risk site, for example, when the displacement detection device is installed above the collapse risk zone, the branch line is extended by the ground movement and is pulled out to the detection device. When the displacement detection device is installed below the collapse risk area, the branch line contracts due to the ground movement, and operates on the side pulled into the detection device. In the displacement detection device, a linear motion commensurate with the movement of the collapsed ground is reproduced, but whether the motion is extended or contracted is determined by the installation location of the device. Therefore, if the space for receiving the cumulative movement set in the apparatus is a structure that can arbitrarily select the initial setting position in the displacement detection apparatus, the displacement receiving space should be provided only in the direction in which the displacement can occur. Often, half the length of the structure of the example of Patent Document 1 assuming bidirectional movement is sufficient.

  When the cumulative displacement of the ground or unstable rocks where the danger of collapse exceeds the expected range, if the collapse does not occur, the displacement acceptance space in the detection device becomes saturated due to the transition, and as a detection device The function cannot be performed. The present invention senses that the accumulated movement amount of the observation point has reached the limit of the displacement acceptance range in order to restore the initial setting state to the apparatus again and to enable continuous observation even in such a situation. In addition to providing a limit switch and adjusting the length of the branch line, the total length of the tension transmission line from the observation point to the constant tension spring is adjusted, and the constant tension spring can be returned to the initial setting position to continue observation. Making it possible.

  The signal of the limit switch is transmitted by wire or wireless to an alarm device installed at another place, and is notified to a supervisor or a maintenance person of the facility. In installation locations where maintenance is relatively easy, the branch line length can be adjusted manually, but in installation locations where maintenance is difficult, the branch length adjustment mechanism in the displacement detector can be controlled by a remote control from the alarm device. For example, it can be operated remotely.

  The terrain where the risk of landslide and rock collapse is inevitably steep terrain, and the displacement detection device according to the present invention is installed on such steep terrain. Therefore, the branch line laid between the unstable ground and the detection device is laid with an inclination along steep terrain, while the detection device itself is installed in a plane on a pedestal for eliminating the influence of running water and the like. It will be attached at an angle different from the slope of unstable ground. In any case, it must be assumed that the inclination angle of the branch line and the detection device does not coincide with each other, which means that the branch line is drawn from the detection device at an unspecified angle with respect to the detection device.

  The branch line laid at a steep angle will be exposed to rainfall and snowfall, but when the transition detection device is installed below the inclined surface, rainwater and snowmelt water attached to the branch line will travel along the branch line. Guided into the transition detector. Usually, such a branch line has a structure in which it is difficult to waterproof with rubber packing or the like, and it must be pulled out at an unspecified angle, because the wire is based on multiple wires that form irregularities on the surface. Since the above requirements must be satisfied, a waterproof effect cannot be expected with rubber packing or the like usually used in such a place.

  In the displacement detection device of the present invention, two pulleys that are closely opposed to the branch line pull-out portion are arranged, and the branch line drawn from the outside between the closely opposed pulleys is further directed upward at least horizontally by another pulley. It is structured to be introduced into the apparatus after being led to. The branch line passes between the two closely facing pulleys, so that it is possible to move in and out without any resistance toward any angle in the vertical direction, and water drops that have fallen along the branch line are reversed. It is not possible to follow the branch line guided upward, and drains water between the pulleys.

  In the displacement detection device of the present invention, the draining pulley is arranged on a wall surface of a recess formed in a part of the lower side of the device. As a result, the pulley is installed in an open space that is not directly exposed to wind and rain, draining is ideally performed, and the draining portion and the device main body mechanism are shielded by the device wall and inserted through a bush made of an elastic body. By introducing the branch line into the apparatus, water intrusion into the apparatus is prevented. Further, the branch line introduction recess formed in the lower portion of the displacement detection device can be further improved in waterproofing by shielding with a cover or the like if necessary.

  The danger scene where the displacement detection device as described above must be installed is on steep terrain and is not in a condition that can be monitored constantly. An alarm device that receives a danger signal detected by a displacement detector and notifies the danger by means of an emergency light or a danger signal sound is practical only if it is installed in a location separate from the displacement detector that detects a collapse. In addition, there is an advantage that a plurality of displacement detection devices can be monitored by a single alarm device by separating them from each other. The basic concept regarding these configurations is as shown in Patent Document 1, but the present invention is an improvement of the structure of the contents of the electrical signals that are individually installed and respond between the displacement detection device and the alarm device. It has become different with it. In the case of Patent Document 1, only a signal in which a displacement greater than or equal to a fixed amount has occurred within a fixed time is to be transmitted from the displacement detection device to the alarm device. The reset power source for driving the electromagnetic solenoid or the like is transmitted from the alarm device side to the displacement detection device.

  Further, the ground collapse prediction device of the present invention has a function of transmitting a limit signal from the displacement detection device to the alarm device when the accumulation of ground displacement exceeds a fixed amount. In reality, when designing a displacement detector, the structure is determined by assuming the cumulative travel distance that inevitably collapses, so it is rare that an unexpected situation occurs when a limit signal is issued. It is considered a situation. However, for example, in a displacement detection device installed in a place where a maintenance person cannot approach, it is necessary to cope with a rare situation, and it is necessary to perform initial setting recovery in the displacement detection device by remote control. These remote operations are performed by a motor or the like that is driven by power transmitted from the alarm device, and these are advanced forms of the present invention.

  FIG. 1 is an explanatory view showing a first embodiment of a displacement detection device according to the present invention, in which A is a plan view with a part cut away except for an upper lid, and B is a side cross-sectional view showing overlapping main parts. Parts are indicated by dotted lines. C is an enlarged detail view of the clutch portion. This device has a measurement point setting unit 10 that is fixed to a measurement point on the ground (a point where a collapse is expected) and a displacement detection device that is fixed to another set point on the ground (a point considered to be stable). Then, the detection wire 14 is stretched between the two, and one end of the detection wire 14 is tensioned by a constant tension spring 50 to which the tension is indirectly transmitted, and the ground collapses due to the amount of displacement of the detection wire 14. It is a structure that predicts.

  The measurement point setting unit 10 has a structure in which a wire is fixed to the ground with a measurement bolt (anchor bolt) 20 through a wire fixture 16 and a hinge fitting 18 that can be rotated in a plane direction, which fix a wire terminal portion. Since the wire is stretched substantially parallel to the slope on which the apparatus is installed, the wire is perpendicular to the measuring bolt 20 that is driven at a substantially right angle to the slope, and can be turned in the horizontal direction. The direction to the transition detection device 12 can be matched by the action of the hinge fitting 18.

  The detection wire 14 is guided to a plurality of introduction pulleys 22 provided in recesses formed on the bottom surface of the displacement detection device 12, and inserted through a bush 24 made of an elastic body provided on the wall of the displacement detection device 12. , Pulled into the sensing device. Two of the introduction pulleys 22 are vertically attached to the outlet of the detection wire 14, and can be inserted without resistance even if the detection wire 14 causes an angular difference in the vertical direction with respect to the displacement detection device 12. When the detection wire 14 that has passed between the opposing pulleys is guided upward by another introduction pulley, the rainwater guided by the detection wire 14 or the attached dew condensation water is combined with the function of the bush 24 described above. It has a structure that drains water.

  The detection wire 14 passes between the positioning pulleys 26 provided in the displacement detection device 12 and is wound and fixed to the winding drum 28 so that the extra length is accommodated. By the action of 26, the detection wire 14 always passes through the center of the bush 24 regardless of the fluctuation of the winding position with the increase / decrease in the number of windings. In addition, by arbitrarily selecting the winding amount in the winding drum 28, it becomes possible to adjust the extra length of the wire, and finally the measurement point fixed at the point where collapse is expected. It is possible to adjust the total length from the setting unit 10 to the constant tension spring 50, and the constant tension spring 50 can be used when monitoring does not occur after displacement exceeding the expectation of the measurement point setting unit 10 and it is necessary to continue monitoring. It has a structure that makes it possible to return to the initial setting state.

  Finally, the tension of the constant tension spring 50 is constantly applied to the detection wire 14, but the tension of the constant tension spring 50 is acted on by the transmission wire 34 that goes around the moving pulley 30 and the fixed pulley 32. It is transmitted to the detection wire 14 indirectly by doubling the working force while halving the stroke.

  The movable pulley 30 is attached to a linear motion stage 37 on the guide rail 36 together with a take-up drum 28, a pinion gear 38 and a sensor plate 44, which will be described later, and the detection wire 14 and the detection wire 14 are fixed. Although the structure is such that the tension spring 50 moves to a position where the tension is balanced, a rotational force is applied to the pinion gear 38 meshed with the rack gear 35 fixedly installed in parallel with the guide rail 36. The sensor plate 44 to which this rotational force is transmitted through the frictional force of the rotary shaft 39 and the clutch plate 40 (refer to C hereinafter) is configured to rotate while moving.

  When the sensor plate 44 is in a free state, the rotational force of the rotary shaft 39 is transmitted by the clutch plate 40 to which the pressing force is applied by the clutch spring 41, but the pressing force is applied to the clutch plate 40 by the electromagnetic solenoid 42. When the spring force of the applied clutch spring 41 is pulled back, the coupling with the pinion shaft 39 is released. The sensor plate 44 formed so that the position different from the rotation center becomes the center of gravity is autonomous at an angle such that the center of gravity is positioned directly below the rotation center by its own weight when the coupling with the rotation shaft 39 is released. Self-recovery.

  On the outer periphery (refer to B below) of the sensor plate 44, a missing portion or an excitation portion that can be detected by the non-contact position sensor 46 is provided, and the rotation of the sensor plate 44 reflecting the change of the measurement point setting portion 10 is provided. This is detected only when the angle exceeds a certain amount, and the signal is taken out by the transmission connector 52 and connected to the alarm device 60 (see FIG. 4, which will be described later) separately and separately by a communication cable. It is a structure that is transmitted as a collapse danger signal. In addition, the mint switches 47 and 48 are attached to both sides of the linear motion stage 37 so that the operation limit of the linear motion stage 37 is detected and the signal is transmitted to the alarm device 60 in the same manner as the danger collapse signal. There is a structure that can monitor the danger from the safe area without approaching the dangerous area.

  FIG. 2 is a diagram showing a side cross section on the opposite side of the first embodiment of the displacement detection apparatus according to the present invention, in which A is an overall view and B is an enlarged detailed view of a winding drum portion. A bolt knob 54 is provided on the end face of the take-up drum 28 (shown in FIG. 1) for facilitating swiveling. In order to prevent the detection wire 14 from being pulled back, a rotation stop gear 56 and a leaf spring 58 are provided. A reverse rotation prevention mechanism by combination is provided. By making the leaf spring 58 symmetrical, the rotation prevention direction can be set in the reverse direction, so that the entire apparatus is installed in the direction in which the constant tension spring 50 is stretched or contracted by the movement of the measurement point setting unit 10. The correspondence can be arbitrarily selected depending on whether it is installed in the direction to perform. Further, by turning the bolt knob 54 with a motor or the like, it becomes unnecessary to directly operate the displacement monitoring device for maintenance.

  FIG. 3 is a view showing a second embodiment of the displacement detecting apparatus according to the present invention, in which A is a plan view with a part cut away except for an upper lid, B is a side sectional view thereof, and overlapping main parts are indicated by dotted lines. ing. In the case of the first embodiment, the acting force of the constant tension spring 50 is doubled by interposing a moving pulley. However, in this proposal, winding drums having different diameters provided on the same shaft with steps are used. Accordingly, the acting force of the constant tension spring 50 is doubled by indirectly transmitting the tension to the constant tension spring 50 through the detection wire 14 from the measurement point setting unit 10.

  In the case of the first embodiment, the pinion gear meshing with the rack gear is moved and rotated in order to obtain the rotational force of the sensor plate 44. However, in this proposal, the transmission wire 34 is rotated around the outer periphery of the wire pulley 64 to detect the rotation. The linear motion transmitted from the wire 14 is converted into a rotational motion. The structure in which the converted rotational power is transmitted to the sensor plate 44 by the clutch mechanism and the reset motion is automatically repeated is the same as the structure of the first embodiment. Between the fixed pulley 32 and the wire pulley 64, two opposing guide pulleys 66 are interposed to prevent the transmission wire 34 from falling off, and the winding direction of the transmission wire 34 with respect to the wire pulley 62 is arbitrarily selected and changed. Regardless of the direction, the position of the position sensor 46 relative to the sensor plate 44 can be set at a fixed position.

  The terminal end of the transmission wire 34 is wound around the drive drum 62 while receiving the tension of the constant tension spring 50, and the tension of the constant tension spring 50 is converted to torque so as to act on the winding drum 28 having a small comparison diameter. ing. The detection wire 14 taken up by the take-up drum 28 has a structure in which a tension which is increased in inverse proportion to the diameter ratio between the drive drum 62 and the take-up drum 28 is applied. Further, in the case where the constant tension spring 50 is deformed to the maximum when the initial setting is performed and the allowable displacement amount is provided, limit switches 47 and 48 are provided so that the use limit can be detected and the initial setting recovery can be confirmed. .

  In the normal state, the drive drum 62 and the take-up drum 28 are coupled by meshing between the rotation stop gear 56 and the leaf spring 58 and rotate at the same rotational speed in the same direction. For example, when the detection sensor 14 is pulled excessively, the number of turns of the detection wire 14 in the winding drum 28 increases, and the number of turns of the transmission wire 34 in the drive drum 62 decreases. The wire length is adjusted by turning only the drive drum 62 while fixing the winding drum 28. In this case, a fixing hook 68 is provided to fix the winding drum 28. The shape of the leaf spring 58 and the fixed hook 68 is a structure that can be dealt with by using a symmetrical shape when the apparatus is installed such that the detection wire 14 is pulled out due to the change of the measurement point setting unit 10. It is.

  In the present invention, a ground prediction system is configured by combining the above displacement detection device and an alarm device that receives an alarm signal transmitted from the displacement detection device and issues a ground collapse warning. An example of the alarm device is shown in FIG. A represents a plane, and B represents a side surface. The alarm device 70 is provided with an alarm lamp 74 on the top surface of the housing 72 that is easy to see, and a lamp switch 80 that also serves as a display on the top surface that is easy to operate. An equal number of receive connectors 78 are provided. The function of the switch that also functions as a display is to display the transition detection device that is transmitting a danger signal for collapse and a saturation signal individually by lighting, and if necessary, the electromagnetic solenoid drive power supply in the monitored transition detection device And the state of other electrical signals are individually monitored and controlled.

  The signal transmitted from the displacement detection device includes the danger prediction signal transmitted by detecting the movement of the measurement point setting unit within a certain time, and the cumulative movement amount of the measurement point setting unit, which indicates the allowable movement amount of the displacement detection device. It is a saturation signal that is transmitted when it exceeds. The alarm device receives these signals, informs the supervisor of the danger of ground collapse by an alarm light or alarm sound, and receives a saturation signal to perform proper maintenance of the transition detection device, and at regular intervals. Therefore, when the electromagnetic solenoid drive power for resetting operation is transmitted and the cumulative displacement of the measurement point setting section reaches the allowable displacement, the cumulative movement in the transition detector is automatically restored to the initial setting state. Transmits the motor drive power for this purpose.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to such a configuration, and the case where wireless communication is performed corresponding to the terrain where it is difficult to lay communication lines. In response to the terrain where it is difficult to obtain a power source, a progressive system such as a self-power source using a solar cell can be considered. Even in such a case, the displacement sensing device with the sensing structure described so far, which senses the sign of landslide by the expansion and contraction of the wire stretched between the two points, can be used safely as a basic component of the system. A ground collapse monitoring system incorporating a monitoring device that can be monitored while being maintained in a zone does not depart from the basic concept of the present invention, and is included in this category.

Explanatory drawing which shows one Example of the branch line type ground collapse prediction apparatus concerning this invention. The other explanatory drawing of the branch line type ground collapse prediction apparatus shown in FIG. The figure which shows the other Example of the branch line type ground collapse detection apparatus concerning this invention. Explanatory drawing which shows an example of the alarm device of the branch line type ground collapse prediction apparatus concerning this invention.

Explanation of symbols

Number common to all figures 10 Measurement point setting unit 12 Displacement detection device 14 Detection wire 16 Wire fixture 18 Hinge bracket 20 Measurement bolt 22 Introduction pulley 24 Bush 26 Positioning pulley 28 Winding drum 30 Moving pulley 32 Fixed pulley 34 Transmission wire 35 Rack gear 36 guide rail 37 linear motion stage 38 pinion gear 39 rotary shaft 40 clutch plate 41 clutch spring 42 electromagnetic solenoid 44 sensor plate 46 position sensor 47, 47 limit switch 50 constant tension spring 52 transmission connector 54 bolt knob 56 non-rotating gear 58 No. 62 drive drum 64 wire pulley 66 guide pulley 68 fixed hook below FIG. 3 No. 70 alarm device 72 housing 74 alarm lamp 76 power cord 78 receiving connector 80 lamp switch below FIG.

Claims (4)

In the ground collapse prediction device that detects the positional change between the fixed points of the branch line by expanding and contracting the branch line laid between multiple points, thereby predicting the ground collapse, it was installed in the displacement detection device fixed to the stable ground It is equipped with a displacement detection mechanism that detects the displacement between measurement points by pulling one end of the branch line, and by the rotation angle of the rotating body that rotates by the rotational force obtained by converting from the expansion and contraction linear motion of the branch line end, The shape of the rotating body in the displacement detector is an eccentric rotating plate whose center of gravity is at a position different from the center of rotation, and the rotational force obtained from the movement of the branch line is transmitted via the clutch device, and the rotational restricting force Is periodically released, the eccentric rotating body periodically returns to its natural position from the middle of its operation due to its own weight, and the displacement within a fixed time from the zero point after the return. Ground collapse prediction apparatus characterized by having a displacement detecting mechanism for transmitting a danger signal drives out to exceed the preset value. A combination of a constant-tension spring that exerts a constant restoring force regardless of the amount of deformation and a combination of a moving pulley or a different-diameter pulley that expands the spring force by the combination of the spring inside the displacement detection device according to claim 1. It has a spring force expansion mechanism, and the constant tension spring is connected to an unstable ground and a branch line stretched between the stable ground via a spring force expansion mechanism, and regardless of the amount of expansion / contraction, by the expanded constant tension spring force. A ground collapse prediction device characterized in that a constant tension is applied to the branch line. A plurality of pulleys are arranged in the branch line pull-in part of the displacement detection device according to claim 1, and even if the angle of the branch line with respect to the detection device changes, the branch lines can be moved in and out without resistance and led to the plurality of pulleys. A ground collapse prediction apparatus having a structure for draining rainwater flowing in through a branch line by forming a path that is drawn into the apparatus after the branch line is inverted upward from the lowest point. A displacement detection device incorporating the ground displacement detection mechanism according to claims 1 to 3 and an electrical signal for driving the clutch release mechanism at regular intervals to the detection device, and an eccentric rotator in the detection device A ground collapse that consists of an alarm device that is separate from the detection device that receives a warning signal that is transmitted when the rotation exceeds a predetermined width within a specified time and notifies the danger by an alarm sound or lamp lighting. Prediction device.

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