A displacement recording device, railway bridge inspection system and method

Abstract

The present application relates to bridge inspection technical field, especially in a kind of displacement recording device, railway bridge inspection system and method, displacement recording device includes displacement recording disc, displacement recording arm and control circuit, displacement recording disc includes disc surface and the threshold protrusion of protruding disc surface;Displacement recording arm one end is in contact with disc surface and can move along disc surface, and can be in contact with threshold protrusion;Control circuit includes extrusion switch and wireless signal transmitter, extrusion switch is arranged in displacement recording arm, extrusion switch can be extruded or collision and closed;When displacement recording arm is in contact with threshold protrusion, extrusion switch can be closed, and make wireless signal transmitter send prompt signal.The present application can be triggered by extrusion switch by the contact between displacement recording arm and threshold protrusion, make wireless signal transmitter emit prompt signal, to help the person of patrol to find out the position affected by earthquake greatly to carry out key check quickly, compared with indiscriminate patrol can significantly improve inspection efficiency.

Description

Technical Field

[0001] This invention relates to the field of bridge inspection technology, and in particular to a displacement recording device, a railway bridge inspection system and method. Background Technology

[0002] During track inspection, bridges along the track are usually the most difficult and challenging parts to inspect. This is because bridges are often the weakest points along the track, and they are more likely to suffer damage and large deformations, which can cause significant harm. On the other hand, bridges have complex structures, and damage is often hidden beneath the beams.

[0003] After an earthquake, a rapid inspection of the track is necessary to assess whether it is passable. This inspection should identify any risks such as foreign object intrusion, significant track deformation, bridge deformation, or pier cracks. Earthquakes are characterized by their high frequency, but are predominantly small. It is estimated that about 5 million earthquakes occur globally each year, the vast majority of which (about 99%) are micro-earthquakes with a magnitude of less than 4. These earthquakes are often identified as harmless after multiple post-earthquake checks. When inspecting bridges, indiscriminate inspections can lead to low efficiency, while random inspections carry a significant risk of missed inspections. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems existing in the prior art, where indiscriminate inspection of bridges leads to low inspection efficiency, while random inspections pose a significant risk of missed inspections. This invention provides a displacement recording device, a railway bridge inspection system, and a method.

[0005] In a first aspect, the present invention provides a displacement recording device, comprising: A displacement recording disk, including a disk surface and a threshold protrusion protruding from the disk surface; A displacement recording arm, one end of which contacts the disk surface, the displacement recording arm is movable along the disk surface and can contact the threshold protrusion; The control circuit includes a squeeze switch and a wireless signal transmitter. The squeeze switch is disposed inside the displacement recording arm and can be closed by squeezing or impact. When the displacement recording arm contacts the threshold protrusion, the squeeze switch can close and cause the wireless signal transmitter to emit a prompt signal.

[0006] The displacement recording device of this invention has a threshold protrusion on the displacement recording disk and a squeeze switch on the displacement recording arm. When the relative displacement reaches or exceeds the set threshold range, the squeeze switch is triggered by the contact between the displacement recording arm and the threshold protrusion, causing the wireless signal transmitter to emit a prompt signal. This helps inspection personnel quickly identify areas severely affected by the earthquake for focused inspection, reducing or avoiding missed inspections of severely damaged areas. Compared with indiscriminate inspections, it can significantly improve inspection efficiency. The displacement recording arm and displacement recording disk can also record residual displacement, assisting manual assessment of the damage.

[0007] Preferably, the displacement recording arm is perpendicular to the disk surface, and a first connecting arm is provided at the end of the displacement recording arm away from the displacement recording disk. The displacement recording arm can move closer to or away from the first connecting arm along its own axis. An elastic element is provided between the displacement recording arm and the first connecting arm, and the elastic element can apply a force away from the first connecting arm to the displacement recording arm.

[0008] Preferably, the first connecting arm is provided with a connecting shaft, the displacement recording arm is provided with a receiving groove, the connecting shaft is embedded in the receiving groove and can move relative to the receiving groove, the elastic element is a spring, the spring is sleeved on the connecting shaft, and one end of the spring is connected to the first connecting arm, and the other end is connected to the end of the displacement recording arm.

[0009] Preferably, a marker is fixedly connected to the first connecting arm. The marker is a bent structure, and the end of the marker away from the first connecting arm points towards the side wall of the displacement recording arm.

[0010] Preferably, a threshold stop is provided in the receiving groove, and a protrusion is provided on the connecting shaft. The protrusion can contact the threshold stop, and when the protrusion contacts the threshold stop, the squeeze switch can be closed, and the wireless signal transmitter will emit a prompt signal.

[0011] The displacement recording device described in this invention can monitor three-dimensional relative displacement. When the relative displacement in each direction reaches or exceeds a preset threshold, the wireless signal transmitter can transmit a prompt signal to help patrol personnel quickly find areas that are greatly affected by the earthquake for key inspection. In addition, it can also record the three-dimensional residual relative displacement to assist manual assessment of the damage.

[0012] Preferably, the displacement recording arm includes a displacement pin that contacts the disk surface, and when the displacement pin moves relative to the disk surface, it can leave a mark on the disk surface.

[0013] Preferably, the marker can leave a mark on the side wall of the displacement recording arm when it moves relative to the side wall of the displacement recording arm.

[0014] Preferably, the disk surface is provided with a first scale and a second scale, the scale directions of the first scale and the second scale are perpendicular to each other; the displacement recording arm sidewall is provided with a third scale, the scale direction of the third scale is parallel to the axial direction of the displacement recording arm.

[0015] Preferably, the first connecting arm includes a first component and a second component that are rotatably connected. The first component is connected to the displacement recording arm, and the second component is rotatable relative to the first component about a rotation axis that is parallel to the disk surface.

[0016] Preferably, the displacement recording arm includes a housing, which is a plastic component, and the squeeze switch is disposed within the housing. When the displacement recording arm collides or squeezes the threshold protrusion, or when the protrusion collides or squeezes the threshold stop, the housing can undergo plastic deformation and continuously squeeze the squeeze switch.

[0017] Preferably, the threshold protrusion is annular, and the displacement recording arm is capable of breaking through the threshold protrusion.

[0018] Preferably, the protrusion is capable of breaking through the threshold block.

[0019] Preferably, the displacement recording arm is provided with at least four squeeze switches, which are arranged in a rectangular shape and connected in parallel to the control circuit.

[0020] Preferably, the wireless signal transmitter is embedded in the first connecting arm.

[0021] Preferably, the control circuit includes a first circuit and a second circuit, which are connected by an electromagnetic relay. The wireless signal transmitter is disposed on the first circuit, and the squeeze switch is disposed on the second circuit. When the squeeze switch is closed, the second circuit is connected, the electromagnetic relay is energized, so that the first circuit is connected, and the wireless signal transmitter emits a prompt signal.

[0022] In a second aspect, the present invention provides a railway bridge inspection system, comprising at least two displacement recording devices as described above, wherein the displacement recording devices are disposed between two adjacent beams, or between a beam and an abutment.

[0023] Preferably, the displacement recording disk and the displacement recording arm are respectively connected to different beams, or one of the displacement recording disk and the displacement recording arm is connected to the beam and the other is connected to the abutment.

[0024] Preferably, the displacement recording disk is arranged vertically, and the axial direction of the displacement recording arm is parallel to the transverse direction.

[0025] In a third aspect, the present invention provides a railway bridge inspection method, comprising an inspection track vehicle and a railway bridge inspection system as described above, wherein the displacement recording disk and displacement recording arm protrude from the bridge surface, and the inspection track vehicle is equipped with a camera and a wireless receiving device; comprising the following steps: The inspection track vehicle travels along the line and receives prompt signals through the wireless receiving device. It also obtains displacement information from the displacement recording device through the camera. The displacement information includes residual displacement along the bridge, residual displacement across the bridge, and residual displacement in the vertical direction. If the wireless receiving device receives a prompt signal, it will inspect the bridge sections surrounding the displacement recording device at the source of the prompt signal.

[0026] The railway bridge inspection method described in this invention, by using the displacement recording device as described above, can determine whether the maximum displacement at a certain location exceeds the limit by checking whether the displacement recording device issues a prompt signal. It can also determine the impact of the relative displacement of the bridge on the track by identifying the residual displacement, thereby assisting the engineering personnel in judging the magnitude of the seismic response at that location, thus distinguishing between areas that need to be inspected and general inspection areas, and thus accelerating the inspection rate of the line.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The displacement recording device of the present invention has a threshold protrusion on the displacement recording disk and a squeeze switch on the displacement recording arm. When the relative displacement reaches or exceeds the set threshold range, the squeeze switch can be triggered by the contact between the displacement recording arm and the threshold protrusion, causing the wireless signal transmitter to emit a prompt signal. This helps inspection personnel to quickly identify areas severely affected by earthquakes for focused inspection, reducing or avoiding missed inspections of severely damaged areas. Compared with indiscriminate inspections, it can significantly improve inspection efficiency. The displacement recording arm and displacement recording disk can also record residual displacement, assisting manual assessment of the damage.

[0028] 2. The railway bridge inspection method of the present invention, by using the displacement recording device as described above, can determine whether the maximum displacement at a certain point exceeds the limit by checking whether the displacement recording device issues a prompt signal, and can also determine the impact of the relative displacement of the bridge on the track by identifying the residual displacement, thereby assisting the engineering personnel in judging the magnitude of the seismic response at that point, thus distinguishing between areas that need to be inspected and general inspection areas, and thus speeding up the inspection rate of the line. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the first structure of the displacement recording device described in the embodiments of this application; Figure 2 This is a bottom view of the first structure of the displacement recording device described in the embodiments of this application; Figure 3 This is a front view of the first structure of the displacement recording device described in the embodiments of this application; Figure 4 This is a schematic diagram of a second structure of the displacement recording device described in the embodiments of this application; Figure 5 This is a schematic diagram of the control circuit described in an embodiment of this application; Figure 6 This is a schematic diagram showing the arrangement of the housing and the squeeze switch according to an embodiment of this application; Figure 7 This is a schematic diagram of the support displacement described in the embodiments of this application; Figure 8 This is a schematic diagram of a first connection between the displacement recording arm and the first connecting arm according to an embodiment of this application; Figure 9 This is a schematic diagram of a second connection between the displacement recording arm and the first connecting arm as described in an embodiment of this application; Figure 10 This is a schematic diagram of a third connection between the displacement recording arm and the first connecting arm as described in an embodiment of this application; Figure 11 This is a flowchart of the inspection method described in the embodiments of this application; Figure 12 This is a schematic diagram of the camera used in an embodiment of this application.

[0030] Marked in the image: 1-Displacement recording disk; 11-Panel surface; 12-Threshold protrusion; 14-Inner zone; 15-Outer zone; 2-Displacement recording arm; 21-Arm body; 22-Displacement pin; 24-Elastic element; 25-Marker; 26-Indicator; 27-Outer shell; 28-Receiving groove; 29-Threshold stop; 3-First circuit; 31-First power supply; 32-Wireless signal transmitter; 4-Second circuit; 41-Second power supply; 42-Press switch; 5-Electromagnetic relay; 6-First connecting arm; 61 - First component; 62 - Second component; 7-Second connecting arm; 8-Connecting shaft; 81 - Threshold ring; 82 - Protrusion; 9. Camera. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0032] Unless otherwise specified, the use of terms such as "upper," "lower," "left," "right," "center," "inner," and "outer" to indicate orientation or positional relationships in the description of specific embodiments of the present invention is based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the product / equipment / device is typically placed during use. These terms are merely for the purpose of facilitating the description of the present invention or simplifying the description in specific embodiments, enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a particular device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on the present invention.

[0033] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," and "parallel" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, or parallel, but rather that it can be slightly tilted or have a deviation. For example, "horizontal" merely means that its direction is more horizontal relative to "vertical," not that the structure must be completely horizontal, but that it can be slightly tilted. Alternatively, it can be simplified to mean that the corresponding device / component / element, when set in a "horizontal," "vertical," "suspended," or "parallel" direction, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the present invention.

[0034] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing descriptions of identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0035] Furthermore, in the description of the embodiments of the present invention, "several", "more than", and "a number of" represent at least two. The number can be any number, such as 2, 3, 4, 5, 6, 7, 8, or 9, and can even exceed nine.

[0036] Furthermore, in the description of the technical solution of this invention, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "provided with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to common connection methods in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0037] Example During track inspection, bridges along the track are usually the most difficult and challenging parts to inspect. This is because bridges are often the weakest points along the track, and they are more likely to suffer damage and large deformations, which can cause significant harm. On the other hand, bridges have complex structures, and damage is often hidden beneath the beams.

[0038] After an earthquake, a rapid inspection of the track is necessary to assess whether it is passable. This inspection should identify any risks such as foreign object intrusion, significant track deformation, bridge deformation, or pier cracks. Earthquakes are characterized by their high frequency, but are predominantly small. It is estimated that about 5 million earthquakes occur globally each year, the vast majority of which (about 99%) are micro-earthquakes with a magnitude of less than 4. These earthquakes are often identified as harmless after multiple post-earthquake checks. When inspecting bridges, indiscriminate inspections can lead to low efficiency, while random inspections carry a significant risk of missed inspections.

[0039] In the first aspect, such as Figures 1 to 4 As shown, this application provides a displacement recording device, including a displacement recording disk 1 and a displacement recording arm 2. The displacement recording arm 2 is in contact with the displacement recording disk 1 and can move along the disk surface 11 of the displacement recording disk 1.

[0040] Displacement recording disk 1 and displacement recording arm 2 can be installed on two components respectively, so that the relative displacement of the two components can be reflected by the relative movement of displacement recording disk 1 and displacement recording arm 2; preferably, displacement recording disk 1 and displacement recording arm 2 can be installed between different beams of the bridge, or between the beam and the abutment, to record the relative displacement of the beam, especially to reflect the impact of the bridge on the earthquake, to help the engineering personnel understand the general damage of the bridge, and to help them determine whether a key inspection is needed.

[0041] In some embodiments, the displacement recording disk 1 includes a disk surface 11 and a threshold protrusion 12 protruding from the disk surface 11. One axial end of the displacement recording arm 2 contacts the disk surface 11 and can move along the disk surface 11, and the displacement recording arm 2 can move to contact the threshold protrusion 12. Preferably, the displacement recording device further includes a squeeze switch 42 and a wireless signal transmitter 32. The squeeze switch 42 is disposed inside the displacement recording arm 2. The squeeze switch 42 can be closed by squeezing or impact, and when the displacement recording arm 2 contacts the threshold protrusion 12, the squeeze switch 42 can close and cause the wireless signal transmitter 32 to emit a prompt signal.

[0042] like Figures 1 to 3 As shown, the displacement recording disk 1 can be a plate-like structure, and its material is not limited, such as steel, alloy material, hard plastic, etc. One side of the displacement recording disk 1 is provided with a disk surface 11, which can be flat, but is also possible to be curved as needed. A threshold protrusion 12 is connected to and protrudes from the disk surface 11. The shape of the threshold protrusion 12 is preferably annular. The threshold protrusion 12 divides the disk surface 11 into an inner region 14 and an outer region 15. The inner region 14 refers to the area within the ring of the threshold protrusion 12, and the outer region 15 refers to the area outside the ring of the threshold protrusion 12. In the initial state... The displacement recording arm 2 is located in the inner area 14. When the displacement recording arm 2 moves along the disk surface 11 to the position of the threshold protrusion 12, the displacement recording arm 2 can be relatively squeezed with the threshold protrusion 12, thereby triggering the squeeze switch 42 located in the displacement recording arm 2. Preferably, the displacement recording arm 2 in the initial state points to the center of the annular threshold protrusion 12. The diameter of the threshold protrusion 12 can be set according to the required displacement threshold. As can be seen from the above working principle, the larger the diameter of the threshold protrusion 12, the larger the relative displacement required to trigger the squeeze switch 42, and vice versa.

[0043] Specifically, the displacement recording device includes a control circuit, which includes a first power supply 31, a squeeze switch 42, and a wireless signal transmitter 32. The squeeze switch 42 is disposed inside the displacement recording arm 2 and can be closed by squeezing or collision. When the displacement recording arm 2 contacts the threshold protrusion 12, the squeeze switch 42 can be closed and the wireless signal transmitter 32 will emit a prompt signal.

[0044] The first power source 31 can be a portable power source, such as a dry cell battery or a storage battery, used to power other components. The squeeze switch 42 is an electronic switch triggered by physical pressure or squeezing action. It can be obtained through purchase or customization. The internal circuit of the squeeze switch 42 can be turned on or off by external force squeezing the sensitive area inside the switch (such as a flexible material, air bladder, or piezoresistor). In this embodiment, the circuit is connected after the squeeze switch 42 is triggered. The wireless signal transmitter 32 is a device capable of transmitting wireless signals, such as converting electrical signals into electromagnetic waves and radiating them into space through an antenna. The specific model of the wireless signal transmitter 32 is not limited and can be obtained through purchase or customization. It only needs to meet the requirement that when the circuit is connected, the wireless signal transmitter 32 can transmit wireless signals that can be received and identified. The wireless signal transmitter 32 can be a short-range signal transmitter. The power consumption of such transmitters is usually small. After the circuit is closed, the first power source 31 can power the wireless signal transmitter 32 to work continuously for a period of time so that it can be received and identified by the receiving device.

[0045] In some embodiments, the displacement recording arm 2 can break through the threshold protrusion 12 to move from the inner region 14 to the outer region 15, or from the outer region 15 to the inner region 14. The strength of the threshold protrusion 12 can be reduced by decreasing its thickness or changing its material, thereby reducing the probability of the displacement recording arm 2 tilting or being damaged due to the displacement recording arm 2 breaking through the threshold protrusion 12. This allows the displacement recording arm 2 to more accurately reflect the residual relative displacement between the bridge beams. The residual relative displacement can be obtained by comparing the position of the displacement recording arm 2 relative to the displacement recording disk 1 before and after the earthquake, that is, by calculating the relative displacement between the displacement recording arm 2 and the displacement recording disk 1 during the earthquake. During the process of the displacement recording arm 2 breaking through the threshold protrusion 12, there is a mutual squeezing force between the displacement recording arm 2 and the threshold protrusion 12, which can also trigger the squeezing switch 42.

[0046] In some embodiments, the disk 11 is provided with a first scale and a second scale, the scale directions of the first scale and the second scale are perpendicular to each other; both the first scale and the second scale include a plurality of scale lines arranged along their respective scale directions, and the scale lines of the first scale and the second scale form a scale grid. By reading the position of the displacement recording arm 2 corresponding to the first scale and the second scale before and after the earthquake, the residual relative displacement between the displacement recording disk 1 and the displacement recording arm 2 can be obtained through simple calculation, that is, it can reflect the residual relative displacement between the bridge beams or between the beams and the abutments. Preferably, both the first scale and the second scale include a 0 scale line, a positive scale line and a negative scale line, and the 0 scale lines of the first scale and the second scale coincide. In the initial state, the displacement recording arm 2 corresponds to the 0 scale line. The initial state refers to the state before the earthquake. The displacement recording arm 2 in the initial state can be aligned with the 0 scale line position through calibration.

[0047] The displacement recording device described in this embodiment has a threshold protrusion 12 on the displacement recording disk 1 and a squeeze switch 42 on the displacement recording arm 2. When the relative displacement reaches or exceeds the set threshold range, the squeeze switch 42 can be triggered by the contact between the displacement recording arm 2 and the threshold protrusion 12, causing the wireless signal transmitter 32 to emit a prompt signal. This helps patrol personnel quickly identify areas severely affected by the earthquake for focused inspection, reducing or avoiding missed inspections of severely damaged areas. Compared with indiscriminate inspections, this significantly improves inspection efficiency. The displacement recording arm 2 and the displacement recording disk 1 can also record residual displacement, assisting manual assessment of the damage.

[0048] Preferably, the displacement recording arm 2 is perpendicular to the disk surface 11.

[0049] In some embodiments, the displacement recording arm 2 is provided with a first connecting arm 6 at the end away from the displacement recording disk 1. The displacement recording arm 2 can move closer to or away from the first connecting arm 6 along its own axis. An elastic member 24 is provided between the displacement recording arm 2 and the first connecting arm 6. The elastic member 24 can apply a force to the displacement recording arm 2 along the axial direction of the displacement recording arm 2 and away from the first connecting arm 6, so that the displacement recording arm 2 can press against the disk surface 11.

[0050] The elastic element 24 refers to a component with elastic deformation capability. The presence of the elastic element 24 does not prevent the displacement recording arm 2 and the first connecting arm 6 from moving closer and further apart, but it enables the displacement recording arm 2 and the first connecting arm 6 to have a tendency to move away from each other, thereby enabling the displacement pin 22 to maintain contact with the disk surface 11. In some embodiments, the elastic element 24 is a spring. During operation, the spring is in a compressed state, so that the elastic force of the spring can push the displacement recording arm 2 against the displacement recording disk 1.

[0051] Preferably, the connection between the first connecting arm 6 and the displacement recording arm 2 can be achieved by the fit between the shaft and the groove. That is, a shaft is provided on one of the first connecting arm 6 and the displacement recording arm 2, and a groove is provided on the other. The end of the shaft is embedded in the groove and the shaft can move axially relative to the groove.

[0052] In the first implementation: such as Figures 8 to 10 As shown, the first connecting arm 6 is provided with a connecting shaft 8, which is parallel to the axial direction of the displacement recording arm 2. The displacement recording arm 2 is provided with a receiving groove 28. The connecting shaft 8 is embedded in the receiving groove 28 and can move relative to the receiving groove 28. The elastic element 24 is a spring, which is sleeved on the connecting shaft 8. One end of the spring is connected to the first connecting arm 6, and the other end is connected to the end of the displacement recording arm 2.

[0053] In the second embodiment: the first connecting arm 6 has a boss on the side near the displacement recording arm 2, and a groove in the middle of the boss. The end of the displacement recording arm 2 has a connecting shaft 8 that protrudes toward the first connecting arm 6. The connecting shaft 8 extends into the groove and can move vertically along the groove. A spring is sleeved on the connecting shaft 8, and one end of the spring is connected to the first connecting arm 6 and the other end is connected to the displacement recording arm 2.

[0054] This embodiment preferably uses the first implementation method described above.

[0055] In some embodiments, to facilitate reading the displacement magnitude between the first connecting arm 6 and the displacement recording arm 2, such as Figures 8 to 10 As shown, a marker 25 is fixedly connected to the first connecting arm 6. The marker 25 has a bent structure, and the end of the marker 25 away from the first connecting arm 6 points to the side wall of the displacement recording arm 2, so that the maintenance personnel can know the magnitude of the displacement by reading the position of the marker 25 pointing to the side wall of the displacement recording arm 2.

[0056] Preferably, a third scale is provided on the side wall of the displacement recording arm 2. The scale direction of the third scale is parallel to the axial direction of the displacement recording arm 2, that is, perpendicular to the scale direction of the first and second scales. The third scale includes several scale lines arranged along its scale direction. By reading the position of the indicator 25 corresponding to the third scale before and after the earthquake, the relative displacement between the displacement recording arm 2 and the first connecting arm 6 can be obtained through simple calculation. Since the displacement recording arm 2 is in contact with and perpendicular to the displacement recording disk 1, the relative displacement between the first connecting arm 6 and the displacement recording disk 1 along the axial direction of the displacement recording arm 2 can also be obtained. The first, second, and third scales point to three mutually perpendicular directions, enabling the displacement recording device described in this embodiment to reflect the relative displacement in three directions. Preferably, in the initial state, the indicator 25 points to the 0 scale line of the third scale to facilitate reading calculation. The initial state refers to the state before the earthquake, and the indicator 25 in the initial state can be aligned to the 0 scale line position through calibration.

[0057] In some embodiments, such as Figure 8As shown, a threshold stop 29 is provided in the receiving groove 28, protruding from the inner wall of the receiving groove 28. A protrusion 82 is provided on the connecting shaft 8, protruding from the side wall of the connecting shaft 8. The protrusion 82 can contact the threshold stop 29, and when the protrusion 82 contacts the threshold stop 29, the squeeze switch 42 can close, and the wireless signal transmitter 32 will emit a prompt signal. It can be understood that the inner wall of the receiving groove 28 is part of the outer wall of the displacement recording arm 2. When the protrusion 82 contacts the threshold stop 29, whether the two can squeeze or collide with each other, thereby triggering the squeeze switch 42 in the displacement recording arm 2. Preferably, the threshold stop 29 does not contact the body of the connecting shaft 8. Preferably, the protrusion 82 can break through the threshold stop 29, which is similar to the function of the displacement recording arm 2 breaking through the threshold protrusion 12.

[0058] In other embodiments, such as Figure 9 As shown, a threshold ring 81 is provided on the connecting shaft 8. The threshold ring 81 protrudes from the side wall of the connecting shaft 8. An indicator 26 is provided at the end of the displacement recording arm 2. One end of the indicator 26 contacts the connecting shaft 8 and can contact the threshold ring 81. When the indicator 26 contacts the threshold ring 81, the squeeze switch 42 can be closed, and the wireless signal transmitter 32 will emit a prompt signal.

[0059] The displacement recording device described in this embodiment can monitor three-dimensional relative displacement. When the relative displacement in each dimension reaches or exceeds a preset threshold, the wireless signal transmitter can emit an alert signal to help inspection personnel quickly identify areas severely affected by the earthquake for focused inspection. Furthermore, it can record the residual relative displacement in the three dimensions to assist in further assessment of the damage. Preferably, the three-dimensional relative displacement includes longitudinal relative displacement, transverse relative displacement, and vertical relative displacement.

[0060] In some embodiments, the displacement recording disk 1 is further connected to a second connecting arm 7. The first connecting arm 6 and the second connecting arm 7 can serve as mounting structures to connect with the beams of the bridge, thereby allowing the displacement recording device to be installed and fixed on the bridge to monitor displacement. The first connecting arm 6 and the second connecting arm 7 can be made of hard materials such as metal, alloy, or plastic. The first connecting arm 6 can be connected to the end of the displacement recording arm 2 away from the displacement recording disk 1, and the second connecting arm 7 can be a component extending from the side of the displacement recording disk 1. When the displacement recording arm 2 is squeezed or collided with the threshold protrusion 12, the displacement recording arm 2 can cause relative displacement between the two ends of the arm body 21 and close the squeeze switch 42. The first connecting arm 6 and the second connecting arm 7 can be installed on the upper part of the two main beams at the beam joint, so that the data can be read when the inspection track vehicle passes by.

[0061] In some embodiments, such as Figures 1 to 4As shown, both the first connecting arm 6 and the second connecting arm 7 are plate-shaped or sheet-shaped structures; further, the second connecting arm 7 extends out from the side of the displacement recording disk 1 and its length is relatively short, while the first connecting arm 6 is connected to the end of the displacement recording arm 2 and its length is relatively long; since the first connecting arm 6 and the second connecting arm 7 need to be connected to different beams respectively, in this embodiment the first connecting arm 6 is set to an L-shape.

[0062] In some embodiments, the displacement recording arm 2 includes an arm body 21 and a displacement pin 22. The displacement pin 22 is disposed at the end of the arm body 21 away from the first connecting arm 6. The displacement pin 22 contacts the disk surface 11, and when the displacement pin 22 moves relative to the disk surface 11, it can leave a mark on the disk surface 11.

[0063] The displacement pin 22 can be a needle-shaped, rod-shaped, or conical component, and can be made of a high-strength material, such as stainless steel or alloy. The needle-shaped or conical component enables the position of the displacement pin 22 relative to the displacement recording disk 1 to be accurately readable, which facilitates the calculation of the relative displacement between the two. Making it of a high-strength material can reduce the probability of damage to the displacement pin 22 and help improve accuracy.

[0064] The maximum relative displacement between two components can be determined by the traces, which can be used for a detailed assessment of bridge damage. The end of the displacement pin 22 can be made into a pointed shape, and an elastic element 24 with relatively large elasticity can be used so that the displacement pin 22 can leave a trace on the displacement recording disk 1 when it moves relative to the component. Some coatings that are easy to scratch can also be provided on the disk surface 11, or a material that will change color after being scratched and reacting with air can be used.

[0065] In some embodiments, the marker 25 can further leave a mark on the sidewall of the displacement recording arm 2 when it moves relative to the sidewall of the displacement recording arm 2.

[0066] The maximum relative displacement between the two beams can be determined by the traces. The marker 25 can be a scribe needle with a pointed end that connects to the displacement recording arm 2. During manufacturing, a mutual squeezing force can be created between the scribe needle and the displacement recording arm 2, so that the movement of the scribe needle relative to the displacement recording arm 2 can leave a trace. The outer wall of the displacement recording arm 2 can also be coated with a coating that is easy to scratch, or a material that will change color after being scratched and reacting with air can be used.

[0067] In some embodiments, the first connecting arm 6 includes a first component 61 and a second component 62 that are rotatably connected. The first component 61 is connected to the displacement recording arm 2, and the second component 62 is rotatable relative to the first component 61 about a rotation axis that is parallel to the disk surface 11.

[0068] like Figures 1 to 3As shown, the first component 61 and the second component 62 can be hinged together to form a rotatable joint. This joint allows relative rotation between the first component 61 and the second component 62 but restricts their relative movement, and the axis of rotation is parallel to the disk surface 11. When the displacement recording device is installed on the bridge, the axial direction of the displacement recording arm 2 can be parallel to the transverse direction of the bridge. The displacement recording disk 1 is connected to the beam and the disk surface 11 is perpendicular to the displacement recording arm 2. The first connecting arm 6 is connected to another beam through the second component 62. In this way, the horizontal rotation angle between the two beams can be obtained by reading the rotation angle of the first component 61 and the second component 62. Thus, the horizontal relative rotation angle of the beam can be measured at the same time as the three-dimensional relative displacement for later analysis.

[0069] Preferably, the first component 61 may be provided with a threaded hole, and the second component 62 may be provided with a through hole. After the bolt passes through the through hole, it is connected to the threaded hole. The second component 62 can rotate around the bolt to realize the relative rotation of the first component 61 and the second component 62. Furthermore, the bolt head may be provided with a scale, and the second component 62 may be provided with a pointer. The rotation angle can be obtained by reading the correspondence between the pointer and the scale.

[0070] Preferably, the end face of the displacement recording arm 2 that contacts the disk surface 11 can be set to be relatively large, so that the disk surface 11 can prevent the displacement recording arm 2 from tilting relative to the disk surface 11, thereby allowing the displacement recording arm 2 to maintain contact with the disk surface 11, and making the movement of the displacement recording arm 2 relative to the disk surface 11 reflect the relative movement of the second component 62 and the second connecting arm 7; furthermore, the displacement pin 22 can be a small protrusion provided on the end face of the displacement recording arm 2.

[0071] In some embodiments, to enable the wireless signal transmitter 32 to operate continuously, the displacement recording arm 2 includes a housing 27, which is a plastic component, and a squeeze switch 42 is disposed inside the housing 27. When the displacement recording arm 2 collides or squeezes the threshold protrusion 12, or when the protrusion 82 collides or squeezes the threshold stop 29, the housing 27 can undergo plastic deformation and continuously squeeze the squeeze switch 42, thereby keeping the control circuit in a conducting state, and the wireless signal transmitter 32 continuously transmits wireless prompt signals. The plastic component refers to a structural component with good plastic deformation capability, such as a thin sheet of low carbon steel, a shape memory alloy component, etc.

[0072] In some embodiments, to improve trigger sensitivity, such as Figure 6As shown, the displacement recording arm 2 is equipped with at least four squeeze switches 42, which are arranged in a rectangular shape. The four squeeze switches 42 are connected in parallel and then connected to the control circuit. When one of the squeeze switches 42 is triggered, the circuit is connected so that the wireless signal transmitter 32 continuously transmits a prompt signal. Two of the four squeeze switches 42 are located at the end of the displacement recording arm 2 near the displacement recording disk 1 and are distributed left and right, while the other two are located at the end of the displacement recording arm 2 away from the displacement recording disk 1 and are also distributed left and right. This ensures that the squeeze switches 42 can be triggered in a timely manner whenever the displacement recording arm 2 touches the threshold protrusion 12 at different positions.

[0073] In some embodiments, the wireless signal transmitter 32 is embedded within the first connecting arm 6.

[0074] In some embodiments, the first power supply 31, the squeeze switch 42 and the wireless signal transmitter 32 are connected in series. After the squeeze switch 42 is closed, the first power supply 31 supplies power to the wireless signal transmitter 32.

[0075] In other embodiments, such as Figure 5 As shown, the control circuit includes a first circuit 3 and a second circuit 4. The first circuit 3 and the second circuit 4 are connected by an electromagnetic relay 5. The wireless signal transmitter 32 is installed on the first circuit 3, and the squeeze switch 42 is installed on the second circuit 4. When the squeeze switch 42 is closed, the second circuit 4 is connected, the electromagnetic relay 5 is energized, so that the first circuit 3 is connected, and the wireless signal transmitter 32 emits a prompt signal.

[0076] Electromagnetic relay 5 is a switch that can control larger current and higher voltage with a smaller current and lower voltage. Various models of electromagnetic relay 5 are available, which can be purchased or customized. This embodiment does not limit the specific models. Taking a common electromagnetic relay as an example: Electromagnetic relay 5 includes an electromagnet, an armature, a spring, a moving contact, and a stationary contact. The electromagnet includes an iron core and a coil. The coil is connected to the second circuit 4. One end of the electromagnet has an armature. The electromagnet is fixed on a first bracket, and the armature is fixed on a second bracket. The first and second brackets are hinged. A return spring is also connected between the second and first brackets. The return spring and the armature are distributed on both sides of the hinge point of the second bracket. The second bracket forms a lever structure. The moving contact is located on the side of the armature away from the hinge point. The stationary contact is opposite to and spaced from the moving contact. The stationary and moving contacts are connected to the first circuit 3 as a switch. When the second circuit 4 is energized, the second power supply 41 supplies power to the electromagnetic relay 5, causing the electromagnet to attract the armature, connecting the moving contact to the stationary contact. The first circuit 3 is then turned on, allowing the first power supply 31 to supply power to the wireless signal transmitter 32.

[0077] In some embodiments, the first power supply 31 and the wireless signal transmitter 32 can be embedded in the first connecting arm 6, and the second power supply 41, the squeeze switch 42, the electromagnet and armature of the electromagnetic relay 5 can be embedded in the displacement recording arm 2. After manufacturing, the components are transported to the bridge site for installation.

[0078] In a second aspect, embodiments of this application provide a railway bridge inspection system, including at least two displacement recording devices as described above. The displacement recording devices are disposed between two adjacent beams, or between a beam and an abutment. Preferably, the displacement recording disk 1 and the displacement recording arm 2 are respectively connected to different beams, or one of the displacement recording disk 1 and the displacement recording arm 2 is connected to a beam and the other is connected to an abutment.

[0079] This embodiment provides two installation methods. In the first installation method, the displacement recording disk 1 is set horizontally and the displacement recording arm 2 is set vertically. In the second installation method, the displacement recording arm 2 is set horizontally and parallel to the transverse bridge direction, and the displacement recording disk 1 is set vertically and perpendicular to the displacement recording arm 2. This embodiment of the application preferably uses the second installation method.

[0080] A bridge beam refers to a structural component in a bridge structure that directly bears the load and transfers it to the substructure (piers, abutments, etc.), such as the main beam of a bridge. In some types of bridges, such as simply supported beams, several beams are arranged along the longitudinal direction of the bridge. Displacement recording devices can be installed between adjacent beams in the longitudinal direction to record the relative displacement data between the two beams at that point, thereby reflecting the magnitude of the earthquake's impact and helping to determine whether a focused inspection is needed. The displacement recording device can be connected to adjacent beams via the first connecting arm 6 and the second connecting arm 7, respectively.

[0081] In some embodiments, at least two displacement recording devices as described above are provided along the line. Several displacement recording devices can be installed between different beams of the same bridge or on different bridges. The wireless signal transmitter 32 can use a short-range transmitter to save power and extend the usage time. Its signal distance is determined by the fact that the inspection railcar can receive it when it approaches the location on the line. During inspection, the inspection railcar travels along the line and receives and identifies the prompt signal emitted by the wireless signal transmitter 32. If the prompt signal is received, it means that the maximum relative displacement at that location exceeds the set threshold range, and the location needs to be inspected.

[0082] The railway bridge inspection system described in this embodiment can obtain at least the following information by using the displacement recording device described above: 1. By receiving and recognizing the prompt signals, it can be determined whether the maximum transverse displacement, maximum longitudinal displacement, and maximum vertical displacement at that location exceed the preset threshold range. If they do, it indicates that the seismic response at that location is significant and requires focused inspection, such as manually descending under the beam to inspect components such as bridge supports.

[0083] 2. By obtaining the position of displacement recording disk 1 corresponding to displacement recording disk 1 and the position of marker 25 corresponding to displacement recording arm 2, the transverse residual displacement, longitudinal residual displacement and vertical residual displacement can be obtained.

[0084] 3. By acquiring the traces on displacement recording disk 1 and displacement recording arm 2, the maximum displacement in the transverse direction, the maximum displacement in the longitudinal direction, and the maximum vertical displacement can be determined.

[0085] 4. By knowing the relative rotation angles of the first component 61 and the second component 62, the horizontal rotation angle between the two beams or between the beam and the abutment can be obtained.

[0086] In the above text, maximum displacement is short for maximum relative displacement, which refers to the peak value of the relative displacement between two beams or between a beam and an abutment; residual displacement is short for residual relative displacement, which refers to the relative displacement that remains between two beams or between a beam and an abutment during inspection; longitudinal direction refers to the direction along the longitudinal axis of the bridge, transverse direction refers to the direction perpendicular to the longitudinal axis of the bridge and parallel to the bridge deck, and vertical direction refers to the vertical or approximately vertical direction. In some cases, the main beam of the bridge may have a longitudinal slope, in which case the vertical direction can be the direction perpendicular to the bridge deck.

[0087] It is understandable that the main beams and piers of railway bridges have high rigidity, and the track structure is attached to the main beams. The supports are the most vulnerable components in earthquakes. During line inspection, it is necessary to assess the damage to the supports. The displacement of the supports can be characterized by the relative displacement of the ends of the main beams. By using the data obtained by the displacement recording device mentioned above, the damage assessment of the supports can be completed quickly and conveniently. The analysis process is as follows.

[0088] Part 1: Horizontal misalignment of the transverse bridge beam ends; It is understandable that the relative misalignment of the beam ends in the transverse direction will cause deformation of the track structure. Based on finite element simulation and experimental verification, the damage grading evaluation index determined based on the maximum horizontal misalignment of the beam joint is shown in Table 1 below. In the table, Dhr represents the residual relative misalignment of the beam ends, i.e., the residual displacement in the transverse direction mentioned above, and Dhp represents the peak horizontal misalignment of the beam ends during the earthquake, i.e., the maximum displacement in the transverse direction mentioned above.

[0089] Table 1. Grading Evaluation Indicators for Transverse Horizontal Misalignment of Beam Joints in Bridges

[0090] Part Two: Horizontal misalignment of beam joints along the bridge direction; Due to the presence of the rail adjustment device, the horizontal misalignment of the beam end along the bridge direction under seismic action has little impact on track damage, but will mainly cause damage to the expansion joint. That is, when the horizontal misalignment along the bridge direction exceeds the displacement design value of the expansion joint device, the expansion joint will be damaged, thereby affecting train operation. The classification evaluation index of the horizontal misalignment of the beam joint along the bridge direction is shown in Table 2 below. The displacement design value of the expansion joint is determined by the type of expansion joint and is marked as Ls. Dzp represents the peak horizontal misalignment along the bridge direction, that is, the maximum displacement along the bridge direction mentioned above. In addition, Dzr represents the residual displacement along the bridge direction.

[0091] Table 2. Grading evaluation indexes for longitudinal horizontal misalignment of beam joints

[0092] Part Three: Misalignment of Vertical Beam Joints; Unless foundation settlement occurs, the main beam will not usually have a large vertical displacement. Its permanent displacement (residual displacement) is determined based on relevant repair rules. The evaluation index of residual vertical displacement of beam joint is shown in Table 3 below. In the table, Dvr represents the vertical residual displacement.

[0093] Table 3. Grading Evaluation Indicators for Vertical Displacement of Beam Joints

[0094] Part Four: Beam End Rotation Limits; The i-th horizontal bend angle α at the beam end can be obtained by a displacement recording device installed at the beam end. i According to the design specifications for high-speed railways (TB10621-2014), the horizontal bend angle at the end of the bridge deck should not exceed 1‰ of radians; otherwise, it will affect the safety of high-speed trains and the comfort of passengers. For conventional railways, this limit needs to be determined separately.

[0095] Part 5: Support displacement limits; Support damage can be inferred from the peak horizontal displacement at the beam end. Taking a multi-span simply supported beam as an example, the maximum transverse displacement Dhp at the i-th beam end can be obtained by using several displacement recording devices installed at the beam end. i (i is an integer and ≥1), maximum displacement Dzp along the bridge direction i and relative rotation angle α i This allows us to determine the maximum displacement of each support; Figure 7 Taking a two-span simply supported beam as an example, Figure 7 The maximum displacements of the supports from left to right are D1=Dhp1, D21=Dhp1+L×α1, D22=Dhp2-D21, and D3=Dhp3. In the figure, squares represent abutments, circles represent piers, and L is the distance between the fixed points of the device at the beam end.

[0096] Furthermore, the damage state of the support can be determined by comparing it with the shear displacement d1 of the support pin (for fixed supports becoming movable supports), the design displacement d2 of the support, and the ultimate displacement d3 of the support, as shown in Table 4. In Table 4, Di represents the maximum displacement of the i-th support, specifically referring to... Figure 7 D1, D21, D22, and D3 in the diagram.

[0097] Table 4 Evaluation Indicators for Support Seat Displacement Classification

[0098] This displacement recording device can quickly determine the state of bridge supports and help determine whether the line is passable.

[0099] In a third aspect, embodiments of this application provide a railway bridge inspection method, such as... Figure 11 As shown, the system includes an inspection track vehicle and the railway bridge inspection system described above. The displacement recording disk 1 and displacement recording arm 2 protrude from the bridge surface. The inspection track vehicle is equipped with a camera 9 and a wireless receiving device. The system includes the following steps: The inspection track vehicle travels along the line and receives prompt signals through a wireless receiver. It also obtains displacement information from the displacement recording device through camera 9. The displacement information includes residual displacement along the bridge, residual displacement across the bridge, and residual displacement in the vertical direction. If the wireless receiving device receives a prompt signal, it will inspect the bridge sections around the displacement recording device at the source of the prompt signal.

[0100] Preferably, the displacement information also includes the maximum displacement along the longitudinal direction, the maximum displacement in the transverse direction, the maximum displacement in the vertical direction, and the horizontal rotation angle between the beams.

[0101] The railway bridge inspection method described in this embodiment uses the displacement recording device to determine whether the maximum displacement at a certain location exceeds the limit by checking whether the displacement recording device issues a prompt signal. It can also determine the impact of the bridge's relative displacement on the track by identifying residual displacement, thus assisting engineering personnel in judging the magnitude of the seismic response at that location. This helps to distinguish between areas that require key inspection and general inspection areas, thereby accelerating the inspection rate of the line.

[0102] The inspection railcar may include a car body and rail wheels. By setting the rail wheels, the inspection railcar can travel along the line, thereby completing the inspection of the railway line; camera 9 is a device capable of acquiring image signals, such as... Figure 12As shown, the camera 9 can be positioned at an angle with the displacement recording device to capture the scale information. This information is then compared with the initial position information before the earthquake to calculate the three-dimensional residual displacement, the three-dimensional maximum displacement, and the horizontal rotation angle of the beam. The initial position information before the earthquake can be the information recorded during the last inspection. Alternatively, various data can be automatically acquired using a machine vision device. A machine vision device is an automated system that uses the camera 9, sensors, and computer technology to simulate human visual functions. It mainly includes image acquisition components, processing units, and software algorithms. Data samples can be manually calibrated first, and then automatically recognized through machine training. The wireless receiver refers to a device capable of receiving wireless signals. The model of the wireless receiver is not limited and can be obtained through procurement and customization. It only needs to be able to collect and recognize the prompt signals emitted by the wireless signal transmitter 32.

[0103] The bridge components surrounding the displacement recording device include, but are not limited to, the main beam, piers, supports, and expansion joints. Images of the area below the main beam can be collected by drones, and if necessary, personnel can be organized to go down to the area below the main beam for inspection.

[0104] In some embodiments, it is first determined whether a prompt signal is received. If a prompt signal is received, it means that the historical maximum displacement has exceeded the limit. In this case, a detailed manual inspection should be conducted to check whether the bridge bearings and other components have been damaged. If no prompt signal is received, it is further analyzed whether the residual displacement and the maximum displacement of the bearing have exceeded the limit. Whether the maximum displacement of the bearing has exceeded the limit can be determined by the above method. If so, a detailed manual inspection is required. Otherwise, continue driving to inspect other locations.

[0105] In a fourth aspect, this embodiment provides a comprehensive operation method, including the following steps: Step 1: Analyze the displacement thresholds at the bridge beam ends, including temperature displacement and seismic displacement, and fabricate a displacement recording device based on the displacement thresholds.

[0106] Step 2: Install the displacement recording device to the end of the main beam expansion joint and check the reliability of the connection regularly.

[0107] Step 3: After the earthquake, quickly determine the bridge damage status by reading the residual displacement at the beam ends and receiving alert signals.

[0108] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A displacement recording device, characterized in that, include: The displacement recording disk (1) includes a disk surface (11) and a threshold protrusion (12) protruding from the disk surface (11). The displacement recording arm (2) has one end in contact with the disk surface (11), and the displacement recording arm (2) can move along the disk surface (11) and can contact the threshold protrusion (12); The control circuit includes a squeeze switch (42) and a wireless signal transmitter (32), the squeeze switch (42) being disposed inside the displacement recording arm (2), and the squeeze switch (42) being able to close under pressure or impact; When the displacement recording arm (2) contacts the threshold protrusion (12), the squeeze switch (42) can close and cause the wireless signal transmitter (32) to emit a prompt signal; The displacement recording arm (2) is perpendicular to the disk surface (11). The end of the displacement recording arm (2) away from the displacement recording disk (1) is provided with a first connecting arm (6). The displacement recording arm (2) can move closer to or away from the first connecting arm (6) along its own axis. An elastic element (24) is provided between the displacement recording arm (2) and the first connecting arm (6). The elastic element (24) can apply a force away from the first connecting arm (6) to the displacement recording arm (2). The first connecting arm (6) is provided with a connecting shaft (8), the displacement recording arm (2) is provided with a receiving groove (28), the connecting shaft (8) is embedded in the receiving groove (28) and can move relative to the receiving groove (28), the elastic element (24) is a spring, the spring is sleeved on the connecting shaft (8), and one end of it is connected to the first connecting arm (6), and the other end is connected to the end of the displacement recording arm (2); A marker (25) is fixedly connected to the first connecting arm (6). The marker (25) is a bent structure. The end of the marker (25) away from the first connecting arm (6) points to the side wall of the displacement recording arm (2). The receiving groove (28) is provided with a threshold block (29), and the connecting shaft (8) is provided with a protrusion (82). The protrusion (82) can contact the threshold block (29), and when the protrusion (82) contacts the threshold block (29), the squeeze switch (42) can be closed, and the wireless signal transmitter (32) will emit a prompt signal.

2. The displacement recording device according to claim 1, characterized in that: The displacement recording arm (2) includes a displacement pin (22), which contacts the disk surface (11), and when the displacement pin (22) moves relative to the disk surface (11), it can leave a mark on the disk surface (11); And / or, when the marker (25) moves relative to the side wall of the displacement recording arm (2), it can leave a mark on the side wall of the displacement recording arm (2); And / or, the disk surface (11) is provided with a first scale and a second scale, the scale directions of the first scale and the second scale are perpendicular to each other; the displacement recording arm (2) is provided with a third scale on its side wall, the scale direction of the third scale is parallel to the axial direction of the displacement recording arm (2).

3. The displacement recording device according to claim 1, characterized in that, The first connecting arm (6) includes a first component (61) and a second component (62) that are rotatably connected. The first component (61) is connected to the displacement recording arm (2), and the second component (62) is rotatable relative to the first component (61) about a rotation axis that is parallel to the disk surface (11).

4. The displacement recording device according to claim 1, characterized in that: The displacement recording arm (2) includes a housing (27), which is a plastic component. The squeeze switch (42) is disposed inside the housing (27). When the displacement recording arm (2) collides or squeezes the threshold protrusion (12), or when the protrusion (82) collides or squeezes the threshold stop (29), the housing (27) can undergo plastic deformation and continuously squeeze the squeeze switch (42). And / or, the threshold protrusion (12) is annular, and the displacement recording arm (2) is capable of breaking through the threshold protrusion (12). And / or, the protrusion (82) can break through the threshold block (29).

5. The displacement recording device according to any one of claims 1-4, characterized in that: The displacement recording arm (2) is provided with at least four squeeze switches (42), which are arranged in a rectangular shape and connected in parallel to the control circuit. And / or, the wireless signal transmitter (32) is embedded in the first connecting arm (6).

6. The displacement recording device according to any one of claims 1-4, characterized in that, The control circuit includes a first circuit (3) and a second circuit (4). The first circuit (3) and the second circuit (4) are connected by an electromagnetic relay (5). The wireless signal transmitter (32) is installed on the first circuit (3), and the squeeze switch (42) is installed on the second circuit (4). When the squeeze switch (42) is closed, the second circuit (4) is connected, the electromagnetic relay (5) is energized, so that the first circuit (3) is connected, and the wireless signal transmitter (32) emits a prompt signal.

7. A railway bridge inspection system, characterized in that, It includes at least two displacement recording devices as described in any one of claims 1-6, wherein the displacement recording devices are disposed between two adjacent beams, or between a beam and an abutment; The displacement recording disk (1) and displacement recording arm (2) are respectively connected to different beams, or one of the displacement recording disk (1) and displacement recording arm (2) is connected to the beam and the other is connected to the abutment; The displacement recording disk (1) is set vertically, and the axial direction of the displacement recording arm (2) is parallel to the transverse direction.

8. A method for inspecting railway bridges, characterized in that, The system includes an inspection track vehicle and a railway bridge inspection system as described in claim 7, wherein the displacement recording disk (1) and displacement recording arm (2) protrude from the bridge surface, and the inspection track vehicle is equipped with a camera (9) and a wireless receiving device; the system includes the following steps: The inspection track vehicle travels along the line and receives prompt signals through the wireless receiving device. It obtains displacement information on the displacement recording device through the camera (9). The displacement information includes residual displacement along the bridge, residual displacement across the bridge, and residual displacement in the vertical direction. If the wireless receiving device receives a prompt signal, it will inspect the bridge sections surrounding the displacement recording device at the source of the prompt signal.

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