Highway bridge flatness detection device and detection method thereof

Abstract

The invention relates to a highway bridge flatness detection device and a detection method thereof, and belongs to the detection technology, the highway bridge flatness detection device comprises an expansion joint assembly arranged between two bridges, a detection assembly is arranged in the expansion joint assembly, and a lower mounting seat and an upper mounting seat of the detection assembly are in sliding fit through a guide assembly; a slide rheostat is arranged in a detection box body at the top of the lower mounting seat, a sliding frame on one side of the upper mounting seat is fixed with a sliding contact of the slide rheostat, and buzzing alarm is triggered through a threshold value by adopting a mechanical fusing type triggering principle; the upper mounting seat moves along with the expansion joint assembly to drive the sliding contact to slide to change the resistance, and the detector reversely deduces the displacement through the current change; when transient over-limit displacement occurs, the driving assembly cuts off the deflector rod through mechanical strong force, the potential energy of the spring is released, the alarm loop is forcibly locked, and even if the bridge rebounds and resets, the alarm state is still kept. The problem that evidence of transient impact is difficult to retain in the current highway bridge flatness detection process is solved, the detection precision is high, and an accident physical memory function is achieved.

Description

Technical Field

[0001] This invention belongs to the field of bridge inspection technology, and relates to a highway bridge smoothness inspection device and its inspection method. Background Technology

[0002] Bridge expansion joints, as key components for regulating beam deformation and buffering vehicle loads, are often referred to as "bridge joints." Currently, monitoring of expansion joints mainly relies on electronic displacement sensors (such as LVDTs and draw-wire displacement gauges) in conjunction with a back-end data acquisition system. However, when dealing with "transient extreme conditions" such as heavy-load impacts and short-term earthquakes, existing monitoring technologies still have significant shortcomings, specifically in the following three aspects:

[0003] First, under transient rebound conditions, existing systems are prone to missing hidden damage. When a bridge is subjected to high-speed passage of heavy vehicles or short-term seismic waves, expansion joints may undergo tensile or compressive deformation exceeding the design threshold within milliseconds, subsequently recovering to their original position rapidly due to structural elasticity. Limited by sampling frequency and signal processing mechanisms, traditional electronic sensors often struggle to capture such transient peak displacements; even if the signal is recorded, its brief duration is easily misjudged as noise and discarded by back-end filtering algorithms, resulting in actual structural damage remaining undetected in the monitoring data, creating a safety blind spot of "normal data, but structural damage."

[0004] Secondly, existing systems lack a physical memory mechanism with irreversible characteristics. Current limit alarms mostly rely on the on / off state of electronic contacts or software threshold judgments, which are susceptible to loss of data or state reset upon power failure. Especially in the event of a serious accident, sensors may be damaged due to excessive displacement of the expansion joint, and the monitoring center can only receive a "signal interruption" alarm, unable to distinguish whether it is due to equipment malfunction or irreversible structural damage. This state judgment mechanism, which relies on electrical signals, lacks a mechanical evidence preservation function like a blown fuse, making it difficult to effectively trace and determine responsibility after an accident.

[0005] Third, the system struggles to balance false alarm rates with maintenance costs. To enhance the ability to detect real risks, equipment is often set to a high-sensitivity mode, but this can lead to numerous false alarms due to temperature changes, daily vibrations, and other disturbances, increasing the operational burden. Furthermore, in the event of a real failure, most precision sensors require complete replacement, resulting in high repair costs. This contradiction not only increases maintenance expenditures throughout the entire lifecycle but may also cause delays in management response to real alarms due to frequent false alarms, ultimately weakening the early warning value of the monitoring system. Summary of the Invention

[0006] In view of this, in order to solve the problem that transient impacts are difficult to retain as evidence in the current process of highway bridge smoothness testing and the results are not good, the present invention provides a highway bridge smoothness testing device and testing method.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A highway bridge flatness testing device includes: two bridges, with an expansion joint assembly between the two bridges;

[0009] The detection component is located inside the expansion joint component and includes a lower mounting base, an upper mounting base, and a guide component. The lower mounting base and the upper mounting base are vertically opposite each other and are respectively fixed to the inner walls on both sides of the expansion joint component. The guide component is fixed to the top of the lower mounting base and slides with the upper mounting base.

[0010] The test chamber is fixed to the top of the lower mounting base and includes the chamber and a sliding rheostat installed inside the chamber.

[0011] The detection assembly also includes a sliding frame, which is slidably mounted on one side of the upper mounting base, and its bottom end is fixedly connected to the sliding contact of the sliding rheostat;

[0012] The detector is located on one side of the bridge and contains an ammeter, indicator light, switch and power supply connected in series. Its positive and negative terminals are connected to the upper and lower terminals of the sliding rheostat, respectively. The upper mounting base moves synchronously with the expansion joint assembly, causing the sliding contact to slide along the sliding rheostat and change the resistance value. The detector uses the current change displayed by the ammeter to infer the displacement of the expansion joint assembly.

[0013] As a further improvement to the above technical solution:

[0014] It also includes: an alarm assembly, which includes a mounting cylinder, an upper mounting plate, a sliding column and a lower mounting plate. The mounting cylinder is fixed to the top of the lower mounting base, the upper mounting plate is fixed to the top wall of the mounting cylinder, the sliding column passes through the upper mounting plate and slides through the top of the mounting cylinder, and the lower mounting plate is fixed to the bottom of the sliding column.

[0015] Terminal ring I and terminal ring II are fixed to the bottom of the upper mounting plate and the top of the lower mounting plate, respectively, with their axes coinciding.

[0016] The control cabinet is located on one side of one of the bridges. It contains a battery and a buzzer. When the displacement of the expansion joint assembly exceeds the threshold, the wiring ring I and wiring ring II contact to connect the circuit, and the buzzer sounds an alarm.

[0017] As a further improvement to the above technical solution:

[0018] Both the lower mounting base and the upper mounting base include a guide rail and a plug-in base. The guide rail and the plug-in base are plugged into each other. Multiple bolts are threaded through the top of the plug-in base, and the bottom of the bolts abut against the guide rail and are locked in place.

[0019] Mounting plate I is fixedly provided on one side of the plug-in seat of the lower mounting base, and a rotating seat is welded and fixed on one side of the plug-in seat of the upper mounting base. Mounting plate I is rotatably connected inside the rotating seat.

[0020] As a further improvement to the above technical solution:

[0021] The guide assembly includes a sleeve rod and a sliding rod. The sleeve rod is fixed to the top of the lower mounting plate I. The top of the upper mounting plate I has an oblong groove, and a sliding plate is slidably disposed in the oblong groove. The top end of the sliding rod is welded and fixed to the sliding plate, and the bottom end is slidably engaged with the sleeve rod.

[0022] As a further improvement to the above technical solution:

[0023] The sliding frame includes a slider and an extension rod I. The slider is slidably mounted on one side of the upper mounting plate I, and the extension rod I is vertically welded to one side of the slider.

[0024] The top of the housing has an insertion hole that fits the extension rod I. The bottom of the extension rod I has a through hole I, and a screw I is installed in the through hole I. One end of the screw I is screwed and fixed to the sliding contact.

[0025] As a further improvement to the above technical solution:

[0026] Plug I and Plug II are fixedly installed through one side of the housing. One upper terminal of the sliding rheostat is connected to Plug I via a wire, and one lower terminal is connected to Plug II via a wire. Plug I and Plug II are respectively connected to the positive and negative terminals of the detector via wires.

[0027] As a further improvement to the above technical solution:

[0028] It also includes a drive assembly, which includes a push plate, a spring and a lever. The push plate is slidably disposed in the mounting cylinder and located below the lower mounting plate. The two ends of the spring respectively abut against the bottom of the push plate and the top of the lower mounting base.

[0029] A rectangular hole is provided on the outer wall of the mounting cylinder, and the lever is detachably mounted on one side of the push plate and passes through the rectangular hole;

[0030] The sliding frame also includes an extension rod II, which is welded to one side of the slider. A through hole II is provided at its end. The end of the lever away from the push plate extends into the through hole II. When the displacement of the expansion joint assembly exceeds the threshold, the through hole II and the rectangular hole cooperate to squeeze the lever and break it.

[0031] As a further improvement to the above technical solution:

[0032] A rectangular groove is provided on the top of the push plate, and a threaded hole is provided on one side of the rectangular groove;

[0033] The lever includes screw II and a connecting rod. Screw II is screwed into a threaded hole, and the connecting rod is fixed to the outer end of screw II and has a breakable section.

[0034] As a further improvement to the above technical solution:

[0035] A sealing cover is provided on one side of the enclosure. The mating surface between the sealing cover and the enclosure is equipped with a fluororubber sealing ring. Both plug I and plug II are waterproof aviation plugs. The contact surfaces of the sliding contact and the sliding rheostat are gold-plated.

[0036] A method for testing the smoothness of highway bridges, using the aforementioned highway bridge smoothness testing device, includes the following steps:

[0037] S1. Fix the expansion joint assembly between the two bridges, and assemble the detection assembly, detection box, sliding frame, alarm assembly and control cabinet in sequence. Connect the detector and the sliding rheostat through plug I and plug II.

[0038] S2. When the detector is turned on, the upper mounting base drives the sliding frame to move when the expansion joint assembly is displaced, causing the sliding contact to slide along the sliding rheostat. The detector displays the displacement through the change in current.

[0039] S3. When the displacement exceeds the threshold, the easily broken section of the extension rod II presses the lever and breaks. The spring pushes the push plate and the lower mounting plate to rise, and the wiring ring I contacts the wiring ring II. The buzzer sounds an alarm.

[0040] S4. After the maintenance is completed, replace the lever, reset the push plate and the lower mounting plate, and the device will return to the detection state.

[0041] The beneficial effects of this invention are as follows:

[0042] 1. The highway bridge smoothness detection device disclosed in this invention introduces a "mechanical fusion" monitoring logic. When the displacement of the expansion joint instantaneously exceeds the threshold, the extension rod forcibly squeezes and shears the easily breakable section of the lever. This process is an irreversible physical change; even if the expansion joint rebounds and resets instantly after the impact, the sheared lever cannot recover. After the spring is released, it will continue to push the connecting ring to keep the alarm circuit conductive. This design gives the device the ability to "physically remember" transient emergencies, eliminating missed alarms caused by signal transients or rebound resets, and ensuring that any over-limit impact is permanently recorded until manually reset.

[0043] 2. The highway bridge smoothness testing device disclosed in this invention significantly reduces maintenance costs through a "sacrificial component" design. The lever, acting as a low-cost mechanical fuse, is consumed as the only damaged component in an over-limit event. Compared to traditional sensors where internal precision components (such as grating rulers and potentiometer carbon films) are permanently damaged after over-range stretching, this invention only requires unscrewing the damaged lever screw and replacing it with a new connecting rod to restore function. This eliminates the need to replace the expensive testing housing or recalibrate the sensor, greatly reducing maintenance costs throughout its entire lifecycle.

[0044] 3. The highway bridge smoothness testing device disclosed in this invention eliminates the "false displacement" signal caused by the sag of the rope due to its own weight or the swing of the wind in traditional rope-type sensors by using a precise fit between the T-shaped guide rail and the plug-in seat; at the same time, the sliding frame and the sliding contact of the sliding rheostat are directly and rigidly connected to achieve a linear correspondence between mechanical displacement and resistance change. Combined with the constant voltage power supply design of the detector, the current signal can accurately deduce the displacement.

[0045] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0046] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0047] Figure 1 This is a schematic diagram of the installation location structure of the highway bridge smoothness testing device of the present invention;

[0048] Figure 2 This is a schematic diagram of the installation structure of the detection component inside the expansion joint assembly in this invention;

[0049] Figure 3 This is a schematic diagram of the assembly of the upper mounting base and the guide assembly in this invention;

[0050] Figure 4 This is a schematic diagram of the detection box opening structure in this invention;

[0051] Figure 5 This is a cross-sectional view of the mounting cylinder in this invention;

[0052] Figure 6 This is a schematic diagram of the installation structure of connector ring I and connector ring II in this invention;

[0053] Figure 7 This is a schematic diagram of the lever structure in this invention;

[0054] Figure 8 This is the circuit diagram of the sliding rheostat in this invention.

[0055] Reference numerals: 1. Bridge; 2. Expansion joint assembly; 3. Detection assembly; 31. Lower mounting base; 32. Upper mounting base; 321. Plug-in base; 322. Guide rail; 323. Bolt; 324. Rotating base; 325. Mounting plate I; 326. Waist-shaped groove; 327. Sliding plate; 33. Guide assembly; 331. Sleeve rod; 332. Sliding rod; 34. Detection box; 341. Box; 3411. Socket; 342. Sealing cover; 343. Sliding rheostat; 3431. Sliding contact; 3432. Screw I; 345. Plug I; 346. Plug II; 35. Sliding frame; 351. Slider; 352. Extension rod I; 353. Through hole I; 354. Extension rod II; 355. Through hole II; 4. Control cabinet; 5. Alarm assembly; 51. Mounting cylinder; 52. Upper mounting plate; 521. Wiring ring I; 522. Cable I; 53. Sliding column; 54. Lower mounting plate; 541. Wiring ring II; 542. Cable II; 55. Push plate; 551. Rectangular groove; 552. Threaded hole; 56. Spring; 57. Toggle lever; 571. Screw II; 572. Connecting rod; 573. Easily broken section; 58. Rectangular hole; 6. Detector. Detailed Implementation

[0056] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0057] like Figure 1 The highway bridge smoothness detection device shown is suitable for monitoring the smoothness of expansion joint areas of various highway bridges. It can capture the displacement of expansion joints caused by factors such as load and settlement in real time, and promptly report any deviations from the standard to ensure driving safety and bridge structural stability. Its core design logic is to capture the displacement of expansion joints through mechanical structures, and then convert the mechanical displacement into electrical signals to achieve detection and alarm. All components work together to form a complete monitoring closed loop.

[0058] The core installation process of the device needs to be carried out simultaneously with the construction of the bridge expansion joint. First, the expansion joint component 2 is fixed in the reserved gap between the two bridges 1. The expansion joint component 2 is made of corrugated spring steel wrapped with a high-polymer elastic polymer material. This structural design can dynamically adapt to the thermal expansion and contraction of the bridge, the deflection deformation caused by vehicle loads, and the displacement caused by concrete shrinkage and creep through elastic deformation. At the same time, the corrugated spring steel can enhance the load-bearing capacity and stability of the structure and avoid permanent deformation caused by vehicle rolling. The side wall of the expansion joint component 2 has a reserved flat mounting surface. The mounting surface is finely ground with a roughness controlled below Ra1.6 to ensure a tight fit with the lower mounting seat 31 and upper mounting seat 32 of the detection component 3, reducing detection errors caused by installation gaps.

[0059] like Figure 2 As shown, both the lower mounting base 31 and the upper mounting base 32 consist of a guide rail 322 and a connector 321. The guide rail 322 is made of highly corrosion-resistant 304 stainless steel with a smooth, burr-free surface to ensure smooth sliding. The connector 321 has a corresponding T-shaped slot with a ground inner wall. After the two are tightly inserted, they are fixed by a positioning pin. The clearance between the positioning pin and the pin hole is ≤0.1mm to further ensure installation accuracy. The top of the connector 321 has multiple threaded holes evenly distributed, and each threaded hole has a mounting bolt 323 passing through it. The bolt 323 has an internal hexagonal head for easy operation in confined spaces. After tightening, the bottom end fits tightly against the top surface of the guide rail 322, locking their relative positions through friction to prevent loosening due to vibration. The lower mounting plate I 325 is fixed to one side of the insert seat 321 in the lower mounting base 31 by welding. The weld is made using argon arc welding and is ground after welding to ensure a smooth transition with the surrounding surface, without protrusions or depressions, to prevent interference with the movement of other components. A rotating seat 324 is welded and fixed to one side of the insert seat 321 in the upper mounting base 32. The inner hole of the rotating seat 324 mates with the rotating shaft of the mounting plate I 325, allowing the mounting plate I 325 to rotate freely within the rotating seat 324. This design can accommodate the minor angular deformation that occurs during the use of the expansion joint, avoiding stress concentration caused by rigid constraints. The mounting plates I 325 on one side of the upper mounting base 32 and the lower mounting base 31 are similar in shape but different in connection method. The insert seat 321 in the upper mounting base 32 is rotatably connected to the corresponding mounting plate I 325, while the insert seat 321 in the lower mounting base 31 is fixedly connected to the corresponding mounting plate I 325.

[0060] like Figure 3As shown, the guide assembly 33 is installed between the lower mounting base 31 and the upper mounting base 32. Its core function is to ensure that the displacement of the upper mounting base 32 relative to the lower mounting base 31 always follows the set direction, thus ensuring detection accuracy. The bottom end of the sleeve rod 331 is fixed to the top center of the lower mounting plate I 325 by bolts. The inner wall of the sleeve rod 331 is honed, and the surface finish reaches Ra0.8. The top end of the sliding rod 332 is welded and fixed to the bottom of the sliding plate 327. The outer wall of the sliding rod 332 is chrome-plated to enhance wear resistance and smoothness. The sliding plate 327 is fitted into the waist-shaped groove 326 opened at the top of the upper mounting plate I 325. The length direction of the waist-shaped groove 326 is consistent with the deformation direction of the expansion joint. Guide grooves are provided on both sides of the groove wall. Guide strips are provided at corresponding positions of the sliding plate 327. The guide strips are embedded in the guide grooves to form a lateral limit and prevent the sliding plate 327 from deviating during movement. The sliding plate 327 can slide smoothly in the groove. The sliding surface is coated with lithium-based grease that is resistant to high and low temperatures, which can maintain the lubrication effect under different ambient temperatures, ensuring that the guide component 33 can deform synchronously with the expansion joint without generating additional resistance that affects the normal expansion and contraction of the bridge.

[0061] like Figure 4 As shown, the test chamber 34 is fixed to the top of the lower mounting base 31 by multiple countersunk bolts. The heads of the countersunk bolts are embedded in the surface of the mounting base to avoid protruding and affecting the movement of other components. The chamber 341 is injection molded from ABS engineering plastic, which is lightweight and has high mechanical strength, and can withstand the impact and wear in the outdoor environment. The wall thickness of the chamber 341 is evenly distributed, and reinforcing ribs are set at the corners to enhance the overall rigidity. A fluororubber sealing ring is set at the mating surface between the sealing cover 342 and the chamber 341. After the bolts are tightened, the sealing ring fits tightly with the mating surface to form an effective seal, which can effectively prevent rainwater and dust from entering and corroding the internal components.

[0062] The sliding rheostat 343 is vertically mounted on a bracket inside the housing 341. The bracket is manufactured using a stamping process, with a galvanized surface for rust prevention. It is connected to the housing 341 via a snap-fit ​​connection, facilitating later disassembly and maintenance. The sliding rheostat 343 operates on the principle that changes in conductor length lead to changes in resistance. It has an internal precision resistance rail, with the sliding contact 3431 in close contact. When the sliding contact 3431 moves, the length of the resistance rail connected to the circuit changes, thus altering the overall resistance value. The resistance adjustment range of the sliding rheostat 343 matches the maximum design displacement of the expansion joint. The resistance change is linearly related to the displacement, ensuring that the electrical signal accurately reflects the mechanical displacement. The contact surface between the sliding contact 3431 and the rheostat body is gold-plated to enhance conductivity and wear resistance, ensuring good contact and a stable current signal.

[0063] The slider 351 in the sliding bracket 35 is slidably mounted on one side of the insertion seat 321 of the upper mounting base 32 via a dovetail groove structure. A grease storage groove is provided in the dovetail groove to store an appropriate amount of grease, continuously providing lubrication for the slider 351 and reducing wear during sliding. The bottom of the slider 351 is provided with an elastic block, which mechanically engages with the wedge-shaped surface of the dovetail groove. After the slider 351 is pushed in, the anti-dislodgement function is automatically triggered to prevent the slider 351 from falling off due to vibration from vehicle traffic. The extension rod I 352 is vertically welded to one side of the slider 351. The welding is done using a double-sided welding process, resulting in a full weld. A tensile test ensures that it will not fall off under stress. Its diameter is precisely matched with the diameter of the insertion hole 3411 on the top of the housing 341. After the bottom end of the extension rod I 352 passes through the insertion hole 3411, it is threaded to the sliding contact 3431 through the screw I 3432 in the through hole I 353. After the screw I 3432 is tightened, it is locked with a nylon lock nut to prevent loosening caused by vibration from vehicle passage. This connection method ensures that the displacement of the sliding frame 35 is completely synchronized with the displacement of the sliding contact 3431, avoiding transmission errors.

[0064] One side of housing 341 has fixed plugs I 345 and II 346 running through it. The spacing between them is reasonable, and both are waterproof aviation plugs. The plug contacts are made of copper alloy with a gold-plated finish to enhance conductivity and corrosion resistance. The plug seals are made of silicone rubber. The upper terminal of the sliding rheostat 343 is soldered to plug I 345 via a copper core wire, and the lower terminal is connected to plug II 346 via a wire of the same specification. The wire surface is wrapped with a weather-resistant insulation layer, and the solder joints are sealed with heat-shrink tubing. After heating, the heat-shrink tubing tightly adheres to the wires and solder joints, further improving waterproof and corrosion-resistant effects.

[0065] like Figure 8As shown, detector 6 adopts a portable design. Internally, a circuit board connects the ammeter, indicator light, rocker switch, and DC power supply in series. The circuit board is treated with conformal coating to prevent moisture, salt spray, and mold. The working principle of detector 6 is based on Ohm's law. By measuring the change in current in the circuit, the change in resistance of the sliding rheostat 343 is inferred, thus calculating the displacement of the expansion joint. Inside detector 6, the DC power supply provides a constant voltage to the circuit. When the resistance of the sliding rheostat 343 changes with displacement, the current in the circuit changes accordingly. The ammeter measures and displays this current value. Operators can directly read the displacement of the expansion joint based on the preset correspondence between the current value and the displacement. The ammeter dial is clear and easy to read. The indicator light uses a bright red LED, which is clearly visible even in strong outdoor light. When the current value is within the normal range, the indicator light remains constantly lit, indicating that the device is operating normally. The positive and negative output terminals of detector 6 are connected to plug I 345 and plug II 346 respectively via wires. The wires are made of flexible and aging-resistant copper core cables. During installation, pipe clamps are used to fix the cables to the bridge structure to prevent damage caused by dragging or vehicle running over them.

[0066] like Figure 5 As shown, the mounting sleeve 51 of the alarm component 5 is fixed to the top side of the lower mounting base 31 via a flange. A slotted groove is provided on the flange for easy fine-tuning during installation, ensuring precise alignment with the lower mounting base 31. A rubber gasket is placed between the flange and the mounting base. This gasket provides cushioning, reducing the transmission of vibrations from passing vehicles to the interior of the alarm component 5, protecting internal components. The bottom of the mounting sleeve 51 is open, allowing water to drain. The upper mounting plate 52 is fixed to the inner top wall of the mounting sleeve 51 with screws designed to prevent loosening due to long-term vibration. A sliding column 53 penetrates the upper mounting plate 52 and the top cover of the mounting sleeve 51. A guide sleeve made of wear-resistant PTFE is provided at the mating point between the sliding column 53 and the cover, ensuring smooth and unobstructed sliding of the sliding column 53. The lower mounting plate 54 is fixed to the bottom of the sliding column 53 with a nut. After tightening, the nut is spot-welded to prevent loosening and detachment.

[0067] like Figure 6 As shown, both connector ring I 521 and connector ring II 541 are copper rings with silver plating to increase the conductive contact area, reduce contact resistance, and ensure stable circuit conduction. Their axes coincide, requiring precise alignment during installation with a spacing of 10-15mm. Cables I 522 and II 542 are both double-core shielded cables; the shielding layer effectively resists external electromagnetic interference, ensuring stable signal transmission. One end of the cable is soldered to connector ring I 521 and connector ring II 541 respectively, and the other end extends through the side wall of mounting cylinder 51 to control cabinet 4. The penetration point is sealed with a waterproof heat-shrink terminal; after heating, the heat-shrink terminal tightly wraps the cable to prevent rainwater from seeping into the mounting cylinder 51.

[0068] Control cabinet 4 is installed on the outer side of one of the bridgeheads of bridge 1. The cabinet body is made of cold-rolled steel plate, bent and formed, with a powder-coated surface, providing good rust prevention and protection. Internally, it houses a battery and a buzzer. The battery uses a sealed design to prevent leakage and corrosion of other components, and has overcharge and over-discharge protection functions, extending its service life. The buzzer has different alarm tones, allowing maintenance personnel to quickly identify the type of fault; its operating volume is sufficient to be clearly heard outdoors. The circuit connections within control cabinet 4 form a complete alarm loop. Its working principle is to control the circuit's on / off state through the contact and separation of connection rings I 521 and II 541. When the two connection rings are in contact, the circuit is connected, and the buzzer is energized and sounds; when the two connection rings are separated, the circuit is disconnected, and the buzzer stops working. The wires are neatly arranged and fixed inside the cabinet using wire channels, facilitating future maintenance.

[0069] The drive assembly, working in conjunction with the sliding bracket 35, is a key structure for triggering the alarm circuit. The push plate 55 is slidably mounted inside the mounting cylinder 51, below the lower mounting plate 54. The outer periphery of the push plate 55 fits tightly against the inner wall of the mounting cylinder 51, and its edge is equipped with guide strips that embed into the guide grooves of the mounting cylinder 51, ensuring precise sliding trajectory and preventing deviation. The spring 56 is sleeved on the guide post below the push plate 55, with its bottom abutting against the top of the lower mounting base 31. The spring 56 operates according to Hooke's Law; within the elastic limit, the spring force is proportional to the deformation. During installation, the spring 56 is pre-compressed, storing elastic potential energy to provide an upward thrust for the push plate 55. Washers made of polytetrafluoroethylene (PTFE) are placed at both ends of the spring, which has a low coefficient of friction, reducing wear between the spring and the push plate 55 and the lower mounting base 31, thus extending the spring's service life.

[0070] A rectangular hole 58 is provided on the side wall of the mounting cylinder 51 at the position corresponding to the push plate 55. The edges of the rectangular hole 58 are chamfered to prevent sharp edges from scratching the lever 57. Figure 7As shown, a rectangular groove 551 is formed on the top of the push plate 55, and a threaded hole 552 is formed on one side of the rectangular groove 551. The screw II 571 of the lever 57 is threaded into the threaded hole 552. Thread glue is applied to the threads of the screw II 571 to enhance the connection and prevent loosening due to vibration. The connecting rod 572 is made of high-quality steel. The easily breakable section 573 undergoes special processing, including local thinning and heat treatment, to ensure uniform stress during breakage and control the breaking force within a set range, avoiding the generation of fragments that could affect the operation of other components. The extension rod II 354 of the sliding frame 35 is vertically welded to one side of the slider 351. A through hole II 355 is formed at the end of the extension rod II 354. The inner wall of the through hole II 355 is chamfered to reduce friction with the lever 57 and prevent jamming. The end of the connecting rod 572 of the lever 57 away from the screw II 571 passes through the rectangular hole 58 and extends into the through hole II 355. The two are in clearance fit without forced constraint, which does not affect the normal deformation of the expansion joint. Its working logic is that the displacement of the extension rod II 354 squeezes the lever 57. When the threshold is reached, the stroke of the rectangular hole 58 is triggered to break.

[0071] The working process of the highway bridge smoothness testing device is as follows: When bridge 1 is in normal use, the expansion joint assembly 2 is within the design allowable deformation range. Affected by factors such as temperature changes and vehicle loads, the concrete beam of bridge 1 undergoes thermal expansion and contraction or slight settlement, and the expansion joint assembly 2 deforms accordingly through its own elastic deformation. At this time, the displacement of the upper mounting base 32 relative to the lower mounting base 31 is small, and the sliding frame 35 drives the sliding contact 3431 to move a distance on the sliding rheostat 343 that does not exceed the set threshold. Since the resistance value of the sliding rheostat 343 is linearly related to the displacement, under the constant voltage provided by the detector 6, the current in the circuit remains stable, and the ammeter displays a fixed current value. The operator can determine the specific position of the sliding contact 3431 based on the preset correspondence between the current magnitude and the displacement, and then calculate the actual displacement of the expansion joint. If the displacement is within the allowable range, the indicator light remains constantly lit, indicating that the device is operating normally. Meanwhile, lever 57 remains intact, push plate 55 cannot move upward under the restriction of lever 57, spring 56 is in a pre-compressed state, storing elastic potential energy, wiring ring I 521 and wiring ring II 541 remain separated, alarm circuit is in the open state, and buzzer does not work.

[0072] When the bridge 1 becomes uneven, such as due to a severe impact from an overloaded vehicle or an earthquake, causing the displacement of the expansion joint assembly 2 to momentarily exceed the set threshold, the upper mounting base 32 will have a large displacement relative to the lower mounting base 31, causing the sliding frame 35 to move synchronously. The extension rod II 354 of the sliding frame 35 moves with the slider 351 and drives the connecting rod 572 of the lever 57 to move, so that the stroke of the rectangular hole 58 is matched, resulting in relative compression (similarly, the downward movement also causes compression and breakage through the lower end of the rectangular hole 58). When the compressive force reaches the design fracture strength of the easily fractured section 573, the easily fractured section 573, which acts as a mechanical safety wire, undergoes instantaneous brittle fracture, and the lever 57 loses its constraint on the push plate 55. At this point, regardless of whether the expansion joint assembly 2 quickly rebounds to its original position under elastic action, the alarm action is irreversible. The spring 56 releases its pre-compressed elastic potential energy. According to Hooke's Law, the thrust generated by the spring pushes the push plate 55 upwards along the mounting cylinder 51. After the top of the push plate 55 contacts the lower mounting plate 54, it drives the lower mounting plate 54 to rise synchronously until the wiring ring II 541 at the top of the lower mounting plate 54 makes tight contact with the wiring ring I 521 at the bottom of the upper mounting plate 52, thus activating the alarm circuit. The buzzer in the control cabinet 4 immediately receives power and sounds an alarm. Even if the subsequent sensor circuit is powered off or the sensor is damaged, the physically connected alarm circuit remains closed (powered by the battery), reminding maintenance personnel that a serious over-limit impact event has occurred on the bridge, requiring timely inspection and repair of the bridge 1's flatness. This process achieves a complete transition from transient mechanical impact to a permanent electrical alarm.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A highway bridge flatness detection device, comprising a expansion joint assembly (2) fixedly installed between two bridges (1) and a detection assembly (3) arranged in the expansion joint assembly (2); the detection assembly (3) comprises a lower mounting seat (31) and an upper mounting seat (32) oppositely arranged and fixedly installed on the inner walls of the two sides of the expansion joint assembly (2), respectively; the top of the lower mounting seat (31) is fixedly installed with a guide assembly (33) in sliding cooperation with the upper mounting seat (32) and a detection box (34) for detecting the sliding displacement of the upper mounting seat (32); the detection box (34) comprises a box body (341) and a sliding rheostat (343) arranged in the box body (341); one side of the upper mounting seat (32) is slidingly provided with a sliding frame (35) with the bottom end fixedly connected with an upper sliding contact (3431) of the sliding rheostat (343), characterized in that, The bridge (1) is provided with a detector (6) on one side, and the positive and negative electrodes of the detector (6) are connected with the upper terminal post and the lower terminal post of the slide rheostat (343) respectively. The upper mounting seat (32) drives the synchronous movement of the sliding frame (35) along with the displacement of the expansion joint assembly (2), so that the slide contact (3431) slides along the slide rheostat (343) to change the resistance value, and the displacement of the expansion joint assembly (2) is inversely deduced through the current change displayed by the detector (6); The alarm assembly (5) includes a mounting cylinder (51), an upper mounting plate (52), a sliding column (53) and a lower mounting plate (54). The mounting cylinder (51) is fixed to the top of the lower mounting seat (31), the upper mounting plate (52) is fixed to the top wall of the mounting cylinder (51), the sliding column (53) penetrates through the upper mounting plate (52) and is in penetrating and sliding fit with the top of the mounting cylinder (51), and the lower mounting plate (54) is fixed to the bottom of the sliding column (53). The bottom of the upper mounting plate (52) and the top of the lower mounting plate (54) are respectively fixed with a wiring ring I (521) and a wiring ring II (541) which have the same axis. When the displacement of the expansion joint assembly (2) breaks through the threshold value, the wiring ring I (521) and the wiring ring II (541) contact and connect the circuit, and the buzzer sounds an alarm; The drive assembly includes a push plate (55), a spring (56) and a lever (57). The push plate (55) is slidably arranged in the mounting cylinder (51) and below the lower mounting plate (54). The spring (56) is in abutment with the bottom of the push plate (55) and the top of the lower mounting seat (31) at two ends respectively. A rectangular hole (58) is formed in the outer wall of the mounting cylinder (51), and the lever (57) is detachably arranged on one side of the push plate (55) and penetrates through the rectangular hole (58). The sliding frame (35) further includes an extension rod II (354) welded to one side of the sliding block (351), and a through hole II (355) is formed in the end of the extension rod II (354). One end of the lever (57) away from the push plate (55) extends into the through hole II (355). When the displacement of the expansion joint assembly (2) breaks through the threshold value, the through hole II (355) and the rectangular hole (58) cooperate to extrude and break the lever (57). A rectangular groove (551) is formed in the top of the push plate (55), and a threaded hole (552) is formed in one side of the rectangular groove (551). The lever (57) includes a screw II (571) and a connecting rod (572). The screw II (571) is screwed into the threaded hole (552), and the connecting rod (572) is fixed to the outer end of the screw II (571). The screw II (571) and the connecting rod (572) are an easy-to-break section (573) therebetween.

2. The highway bridge flatness detection device of claim 1, wherein The lower mounting base (31) and the upper mounting base (32) each comprise a guide rail (322) and a socket (321), the guide rail (322) and the socket (321) are in plug-in cooperation, the socket (321) is penetrated by a plurality of bolts (323) at the top, the bottom end of the bolt (323) is in abutment and locking with the guide rail (322); one side of the socket (321) in the lower mounting base (31) is fixedly provided with a mounting plate I (325), one side of the socket (321) in the upper mounting base (32) is welded and fixedly provided with a rotating seat (324), the rotating seat (324) is rotatably connected with the mounting plate I (325) inside.

3. The highway bridge flatness detection device of claim 2, wherein The guide assembly (33) comprises a sleeve rod (331) and a sliding rod (332), the sleeve rod (331) is fixed to the top of the lower mounting plate I (325), the top of the upper mounting plate I (325) is provided with a waist-shaped slot (326), the sliding plate (327) is slidably arranged in the waist-shaped slot (326), the sliding rod (332) is welded and fixed to the top end of the sliding plate (327), and the bottom end is in sliding cooperation with the sleeve rod (331).

4. The highway bridge flatness detection device of claim 3, wherein The sliding frame (35) comprises a sliding block (351) and an extension rod I (352), the sliding block (351) is slidably arranged on one side of the upper mounting plate I (325), and the extension rod I (352) is vertically welded on one side of the sliding block (351); the top of the box body (341) is provided with a jack (3411) matched with the extension rod I (352), the bottom end of the extension rod I (352) is provided with a through hole I (353), the through hole I (353) is provided with a screw I (3432), and one end of the screw I (3432) is screwed and fixed with the sliding contact (3431).

5. The highway bridge flatness detection device of claim 4, wherein The box body (341) is fixedly provided with a plug I (345) and a plug II (346) on one side, one upper terminal post of the sliding rheostat (343) is connected with the plug I (345) through a wire, one lower terminal post is connected with the plug II (346) through a wire, and the plug I (345) and the plug II (346) are respectively plugged into the positive and negative electrodes of the detector (6) through wires.

6. The highway bridge flatness detection device of claim 1, wherein The box body (341) is provided with a sealing cover (342) on one side, and the joint surface of the sealing cover (342) and the box body (341) is provided with a fluorine rubber sealing ring.

7. The method of detecting the device for detecting the flatness of a highway bridge according to claim 5, characterized in that, The method comprises the following steps: S1, the expansion joint assembly (2) is fixed between the two bridges (1), the detection assembly (3), the detection box (34), the sliding frame (35), the alarm assembly (5) and the control cabinet (4) are assembled in sequence, and the detector (6) and the sliding rheostat (343) are connected through the plug I (345) and the plug II (346); S2, when the expansion joint assembly (2) is displaced, the upper mounting base (32) drives the sliding frame (35) to move, so that the sliding contact (3431) slides along the sliding rheostat (343), and the detector (6) displays the displacement amount through the current change; S3, when the displacement exceeds the threshold value, the extension rod II (354) extrudes the breakable section (573) of the push rod (57) to break, the spring (56) pushes the push plate (55) and the lower mounting plate (54) to rise, the terminal ring I (521) is in contact with the terminal ring II (541), and the buzzer sounds an alarm. S4, after the maintenance is completed, the push rod (57) is replaced, the push plate (55) and the lower mounting plate (54) are reset, and the device returns to the detection state.

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