Detection device for detecting cracks of building main body structure

Abstract

The invention discloses a detection device for detecting cracks of a building main body structure, and particularly relates to the technical field of building main body crack detection.The detection device can detect multiple components such as shear walls, beams, columns and floor slabs through a liftable lifting plate, a rotary detection assembly and two marking units, and the universality is higher; during detection, the sliding abutting block abuts against the moving block, so that the moving block extends outwards, the corresponding marking piece makes contact with the building body, the piston seat movably enters the top face of the moving block, and marking liquid in the top face of the moving block permeates into the marking piece along a plurality of small holes; and then the crack starting point of the building main body is rapidly marked through the marking piece, the tail end of the crack area is marked through the other marking piece in the same group of marking units, and a visual mark is formed in the crack area, so that subsequent personnel can rapidly position the crack position and respectively mark the starting point and the terminal point, and the marking range covers the whole defect area.

Description

Technical Field

[0001] This invention relates to the field of building structure crack detection technology, specifically a detection device for detecting cracks in the main structure of a building. Background Technology

[0002] With the development of urban construction, the scale and complexity of buildings are constantly increasing, making the safety of the main building structure one of the core issues in engineering quality control and building safety management. During the use or construction of buildings, cracks are prone to occur in building structures due to factors such as uneven foundation settlement, temperature stress, material aging, external impact, or construction defects, especially in load-bearing components such as concrete beams, columns, shear walls, and floor slabs. The occurrence of cracks not only affects the load-bearing capacity and durability of the structure but may also become a precursor to structural failure. Currently, preliminary assessment is mainly conducted by manually observing the crack morphology (width, length, and direction); this method is simple but highly subjective and difficult to detect hidden cracks or quantify the degree of damage.

[0003] A search revealed that utility model patent CN216208812U discloses an ultrasonic surface crack detection device for buildings, which ensures basic ultrasonic detection effects while allowing for flexible adjustment of the position and height of the detection subject.

[0004] Most existing building structure crack detection devices are applicable to specific components (such as shear walls or beams), making it difficult to be compatible with the positions, heights, and detection angles of different components (shear walls, columns, beams, floor slabs). This results in poor equipment adaptability and weak versatility, making it impossible to perform full-structure inspection on a single platform. After crack detection, it is usually necessary to manually mark the start and end points of cracks or draw the outline of the area, which is time-consuming, has large errors, and involves repetitive work. Especially in environments where crack boundaries are unclear or lighting is insufficient, it is difficult to standardize manual judgment, affecting the efficiency and quality control of the maintenance process. Each change of position requires manual alignment, recalibration, or the use of laser-assisted positioning devices, which is complex to operate, has low detection efficiency, and limits its rapid deployment and use on site. Summary of the Invention

[0005] The purpose of this invention is to provide a detection device for detecting cracks in the main structure of a building, so as to solve the problems mentioned in the background art.

[0006] The main technical problem solved by this invention is: Existing crack detection methods are designed for specific components (such as shear walls or beams), making it difficult to be compatible with the location, height, and detection angle of different components. This results in poor equipment adaptability and weak versatility, making it impossible to achieve full structural inspection on the same platform. Manually marking the start and end points of cracks or drawing the outline of the area is required, which is time-consuming, has large errors, and involves repetitive work. Especially in environments where crack boundaries are unclear or lighting is insufficient, it is difficult to standardize manual judgment, which affects the efficiency and quality control of the maintenance process. Each change of location requires manual alignment and recalibration or the use of laser-assisted positioning devices, which is complex to operate and has low detection efficiency, limiting its rapid deployment and use on site.

[0007] This invention can be achieved through the following technical solutions: A detection device for detecting cracks in the main structure of a building includes a second track arranged parallel to the main structure of the building, a first track arranged perpendicular to the main structure of the building connected to the second track, a U-shaped test frame slidably mounted on the first track, lifting plates raised and lowered on the inner walls of both sides of the test frame, and the same rotatable detection component slidably mounted vertically on the inner walls of both lifting plates. The detection assembly includes a rotatable rotating plate, with a base plate mounted on the inner wall end of the two rotating plates. An electric push rod is mounted on the surface of the base plate, and the pushing end of the electric push rod is connected to a detection box that slides along the limiting position of the rotating plate. The side of the detection box facing the main building is open. The inside of the testing box is equipped with a slider that slides horizontally. The slider is connected to a testing seat via a support rod. A testing module is installed in the middle of the testing seat. Two sets of marking units are provided on the outside of the testing module. Each marking unit includes two moving blocks that are lifted and installed in the detection seat and arranged symmetrically on an axis. The inner cavity of the detection seat is provided with a pushing block, which is abutted against the corresponding moving block. Each moving block has a piston seat movably connected to its top surface via an elastic element. The upper end of the piston seat is provided with a marker, and the surface of the piston seat is provided with several small holes for the marking liquid to pass through. A second spring is sleeved on the outside of the moving block, and the end of the second spring is fixed to one inner wall of the detection seat; The detector housing is equipped with an adjustment unit for controlling the simultaneous or asynchronous movement of the push blocks in each group of marking units.

[0008] A further technical improvement of the present invention is that: the inner cavity of the detection seat is provided with a liquid storage tank, and the discharge end of the liquid storage tank is provided with a solenoid valve and is connected to the interior of the moving block through a hose.

[0009] A further technical improvement of the present invention is that: the adjustment unit includes a bevel gear driven by a servo motor, and the inside of the detection seat is provided with four concentric slide rails, with the extension lines of two adjacent slide rails arranged perpendicularly. Each slide rail is equipped with a vertical plate, and a second bevel gear that meshes with a first bevel gear is rotatably mounted on the vertical plate. Each second bevel gear has a threaded push rod that is connected to the corresponding push block.

[0010] A further technical improvement of the present invention is that: a sliding block is slidably provided in the track on the inner wall of the lifting plate, and the sliding block is rotatably arranged with the rotating plate; Two lifting cylinders that move simultaneously are installed in the cavity at the bottom of the test frame, and each lifting cylinder is fixed to the bottom surface of the corresponding side lifting plate.

[0011] A further technical improvement of the present invention is that a rolling switching unit is installed in the bottom cavity of the test frame. The rolling switching unit includes an eccentric wheel one and an eccentric wheel two that are fixedly sleeved with the drive shaft. After the eccentric wheel one rotates half a turn, it coincides with the eccentric wheel two. The bottom of the eccentric wheel one is provided with a roller one that rolls along the track one, and the bottom end of the eccentric wheel two is provided with a roller two that rolls along the track two.

[0012] A further technical improvement of the present invention is that a fixing plate is provided below the drive shaft, and a buffer reset unit for use by roller one and roller two is provided on the fixing plate; The buffer reset unit includes a buffer seat. The mounting seats of roller one and roller two are each provided with a pressure ring that slides along the limit of the buffer seat. A spring one is sleeved on the outside of the pressure ring, and one end of the spring one is fixed to the fixing plate. The bottom surface of the fixed part is provided with a limiting seat that slides and fits in contact with the mounting seats of roller one and roller two.

[0013] A further technical improvement of the present invention is that: both track one and track two are mounted on the bonding plate, and a transfer rail is rotatably provided at their junction; The transfer track has the same width as both track one and track two.

[0014] A further technical improvement of the present invention is that: one end of the test frame is connected to two flexible suction cups via telescopic units, and the flexible suction cups are fixed to the building body by vacuum pump.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. With a liftable lifting plate, rotating detection components, and two sets of marking units, it can detect multiple components such as shear walls, beams, columns, and floor slabs, making it more versatile. During detection, the sliding push block pushes against the moving block, causing the moving block to extend outwards. Meanwhile, a corresponding marking element contacts the building structure, allowing the piston seat to move into the top surface of the moving block. The marking liquid inside the top surface of the moving block seeps into the marking element through several small holes. The marking element then quickly marks the starting point of the crack in the building structure, while another marking element in the same marking unit marks the end of the crack area. This automatically creates a visual mark in the crack area, facilitating quick location of the crack position, range, and repair area for subsequent personnel, saving time on manual searching and comparison. The starting and ending points are marked according to the detection signal, ensuring that the marking range covers the entire defect area. 2. By setting up a rolling switching unit and a transfer rail, the positions of eccentric wheel one and eccentric wheel two change due to the rotation of the drive shaft. Roller two is exposed outward and enters into track two. Through the rotation of the transfer rail, it is arranged along the direction of track two, which facilitates the rolling of roller two. It can selectively extend according to the operation stage to realize the switching of the sliding track. It can accurately detect different positions of the building body along track two without the need for separate correction and alignment, effectively improving the accuracy and efficiency of crack detection and eliminating the need for additional manual straightening or laser positioning mechanisms. 3. After the test frame moves to the target detection position, the telescopic unit applies an appropriate abutment force to the flexible suction cup to keep it in a close fit and ensure a firm adsorption. Then, the vacuum pump is activated to generate negative pressure inside the flexible suction cup. After the flexible suction cup comes into close contact with the outer wall of the building, it generates an adsorption force. Through its internal elastic material, it adapts to the slight unevenness of the building surface. The flexible suction cup and the building form a point adsorption support, which prevents the test frame from shaking during the detection process and improves the accuracy of image acquisition and crack identification. Attached Figure Description

[0016] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0017] Figure 1 This is a schematic diagram of the external structure of the present invention; Figure 2 For the present invention Figure 1 A magnified view of a section at point A in the middle; Figure 3 This is a schematic diagram of the internal structure of the test fixture of the present invention; Figure 4 For the present invention Figure 3 A magnified view of a section at point B in the middle; Figure 5 This is a top view schematic diagram of the installation structure of the transfer rail in this invention; Figure 6 For the present invention Figure 3 A magnified view of a section at point C.

[0018] In the diagram: 1. Test frame; 2. Track 1; 3. Track 2; 4. Lifting plate; 5. Flexible suction cup; 6. Rotating plate; 7. Detection box; 8. Base plate; 9. Electric push rod; 10. Detection module; 11. Slide seat; 12. Lifting cylinder; 13. Eccentric wheel 1; 14. Eccentric wheel 2; 15. Buffer seat; 16. Pressure ring; 17. Limiting seat; 18. Roller 1; 19. Roller 2; 20. Spring 1; 21. Transfer rail; 22. Slider; 23. Detection seat; 24. Liquid storage tank; 25. Moving block; 26. Pushing block; 27. Bevel gear 1; 28. Slide rail; 29. ​​Threaded push rod; 30. Bevel gear 2; 31. Vertical plate; 32. Piston seat; 33. Marking piece; 34. Spring 2. Detailed Implementation

[0019] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.

[0020] Please see Figures 1-6 As shown, the present invention provides a detection device for detecting cracks in the main structure of a building, including a second track 3 arranged parallel to the main structure of the building, a first track 2 arranged perpendicular to the main structure of the building connected to the second track 3, a U-shaped test frame 1 slidably arranged on the first track 2, lifting plates 4 raised and lowered on both inner walls of the test frame 1, and the same rotatable detection component slidably arranged vertically on the inner walls of the two lifting plates 4. The detection assembly includes a rotatable rotating plate 6, with a base plate 8 installed on the inner wall end of the two rotating plates 6. An electric push rod 9 is installed on the surface of the base plate 8, and the pushing end of the electric push rod 9 is connected to a detection box 7 that slides along the limiting position of the rotating plate 6. The side of the detection box 7 facing the main building is open. Inside the detection box 7, a slider 22 is horizontally slidable. The slider 22 is connected to a detection seat 23 via a support rod. A detection module 10 is installed in the middle of the detection seat 23. Two sets of marking units are provided on the outside of the detection module 10. Each marking unit includes two moving blocks 25 that are lifted and installed in the detection seat 23 and arranged symmetrically on the axis. The inner cavity of the detection seat 23 is provided with a pushing block 26, which abuts against the corresponding moving block 25. Each moving block 25 has a piston seat 32 movably connected to its top surface via an elastic element. The upper end of the piston seat 32 is provided with a marker 33, and the surface of the piston seat 32 is provided with several small holes for the marking liquid to pass through. A second spring 34 is sleeved on the outside of the moving block 25, and the end of the second spring 34 is fixed to one inner wall of the detection seat 23; The inside of the detection seat 23 is equipped with an adjustment unit for controlling the push blocks 26 in each group of marking units to move simultaneously or at different times; In this design, the main building structure includes shear walls, beams, columns, and floor slabs. The columns are located between two shear walls, the beams are located on the top surface of the shear walls and columns, and the floor slabs are cast-in-place. When using the device, track 1 2 and track 2 3 are laid on the ground, with track 2 3 arranged parallel to the shear wall. The test frame 1 rolls along track 1 2 to the junction of the two tracks, and then rolls on track 2 3 to change the test position, thereby realizing the detection of the main body of the building at different positions. like Figure 1 and Figure 2 As shown, the detection component moves up and down within the tracks on the inner walls of the two lifting plates 4. The lifting height is the same as the height of the shear wall. The opening of the detection box 7 faces the shear wall to detect cracks in the shear wall. Then, the two lifting plates 4 are simultaneously pushed upward, causing the detection box 7 to reach the height of the beam. Then, by rotating the rotating plate 6 clockwise, the opening of the test box 7 faces the bottom surface of the floor slab, that is, the opening is parallel to the floor slab. During each test, the electric push rod 9 pushes the test box 7 to slide along the limiting position of the rotating plate 6, so that the outer wall of the test box 7 fits into the main body of the building. It can test various main bodies of buildings and has stronger versatility. When inspecting shear walls, a multi-height sliding test is used, that is, sliding the test at different positions at the same height, and then sliding the test at the remaining heights. When inspecting the beam, when the inspection box 7 reaches the same height as the beam, the inspection module 10 is used for sliding inspection. When detecting a column, the detection module 10 remains stationary, and the vertical sliding of the lifting plate 4 enables the detection of columns at the same position. When inspecting the floor slab, since the inspection box 7 is parallel to the floor slab, it can directly inspect the bottom surface of the floor slab by sliding. The detection module 10 integrates a lidar and a depth camera, follows the slider 22 as it slides within the detection box 7, and provides supplementary lighting through multiple supplementary lights to ensure a consistent lighting environment during detection and to ensure the accuracy of the detection data. When a crack defect is detected in the main body of the building, the corresponding marking unit marks the crack area. When the two moving blocks 25 move simultaneously, the crack is not obvious and the length of the crack is within the distance between the two moving blocks 25. When the two moving blocks 25 do not move simultaneously, the crack is more obvious and the marking range is wider. During each marking, the sliding push block 26 pushes against the moving block 25, causing the moving block 25 to extend outward. In this state, it compresses the spring 34, and the corresponding marking piece 33 comes into contact with the main body of the building, causing the piston seat 32 to move into the top surface of the moving block 25. The marking liquid inside the top surface of the moving block 25 seeps into the marking piece 33 through several small holes. The marking piece 33 then quickly marks the starting point of the crack in the main body of the building. Another marking piece 33 in the same marking unit marks the end of the crack area, helping the inspectors to quickly identify the crack area and facilitate subsequent repair treatment. Another set of marking units is used to mark vertical cracks.

[0021] See Figure 6 As shown, the inner cavity of the detection seat 23 is provided with a liquid storage tank 24, and the discharge end of the liquid storage tank 24 is provided with a solenoid valve and is connected to the interior of the moving block 25 through a hose. The labeling liquid in the storage tank 24 flows into the inner cavity of the moving block 25 through a solenoid valve in a metered manner, keeping its volume at a dynamic constant value. The hose design avoids motion interference caused by the moving block 25 extending outward.

[0022] See Figure 6 As shown, the adjustment unit includes a bevel gear 27 driven by a servo motor, and the inside of the detection seat 23 is provided with four concentric slide rails 28, with the extension lines of two adjacent slide rails 28 arranged perpendicularly. Each slide rail 28 is slidably provided with a vertical plate 31, and a second bevel gear 30 that meshes with a first bevel gear 27 is rotatably mounted on the vertical plate 31. Each second bevel gear 30 has a threaded push rod 29 that is connected to the corresponding push block 26 inside its threaded sleeve. Since the length of the crack area is unknown, the crack area is identified by the detection module 10. When the crack is obvious, the initial position of the vertical plate 31 does not change, while the other vertical plate 31, which is symmetrical to it, slides, so that the second bevel gear 30 does not mesh with the first bevel gear 27. When the detection module 10 identifies the end point of the crack area, the corresponding vertical plate 31 slides on the corresponding slide rail 28, so that the second bevel gear 30 meshes with the first bevel gear 27, so that the pushing block 26 slides and pushes against the moving block 25. At this time, the moving block 25 extends outward and the end point of the crack is quickly marked by the marker 33.

[0023] See Figure 4 As shown, a slide block 11 is slidably provided in the track on the inner wall of the lifting plate 4, and the slide block 11 is rotatably set with the rotating plate 6. Two lifting cylinders 12 that move simultaneously are installed in the cavity at the bottom of the test frame 1, and each lifting cylinder 12 is fixed to the bottom surface of the corresponding side lifting plate 4; During beam inspection, two lifting cylinders 12 synchronously drive both ends of the lifting plate 4 to ensure that their lifting heights are consistent.

[0024] See Figure 3 and Figure 4 As shown, a rolling switching unit is installed in the bottom cavity of the test frame 1. The rolling switching unit includes an eccentric wheel 13 and an eccentric wheel 14 that are fixedly connected to the drive shaft. After the eccentric wheel 13 rotates half a turn, it coincides with the eccentric wheel 14. The bottom of the eccentric wheel 13 is provided with a roller 18 that rolls along the track 2, and the bottom of the eccentric wheel 14 is provided with a roller 19 that rolls along the track 3. Initially, the roller 18 in test frame 1 is exposed to the outside for rolling on track 2. At this time, the longest end of the eccentric wheel 13 is in contact with the mounting base of the roller 18. During switching, the positions of eccentric wheel 13 and eccentric wheel 14 change due to the rotation of the drive shaft, such as... Figure 4 As shown, at this time, roller 19 is exposed outward and enters track 3. It extends selectively according to the operation stage to realize the switching of the sliding track. It accurately detects different positions of the building body along track 3 without the need for separate correction and alignment, effectively improving the accuracy and efficiency of crack detection. During the track switching process, the roller and track make adaptive contact and maintain stable guidance, eliminating the need for additional manual straightening or laser positioning mechanisms, simplifying the overall system structure and improving the efficiency of detection deployment.

[0025] See Figure 4 As shown, a fixing plate is provided below the drive shaft, and a buffer reset unit for use by roller 18 and roller 29 is provided on the fixing plate; The buffer reset unit includes a buffer seat 15, and a pressure ring 16 that slides along the buffer seat 15 on the mounting base of roller 18 and roller 2 19. A spring 20 is sleeved on the outside of the pressure ring 16, and one end of the spring 20 is fixed to the fixing plate. The bottom surface of the fixed part is provided with a limiting seat 17 that slides and fits in contact with the mounting bases of roller 18 and roller 29; When eccentric wheel 13 and eccentric wheel 24 drive the corresponding roller 18 and roller 29 to switch motion, the mounting base of the two rollers is jointly restricted by the buffer seat 15 and the limiting seat 17 during the sliding process. First, the pressure ring 16 compresses the spring 20 during the sliding process to form a buffer and rebound structure, which absorbs the impact of sudden motion, prevents the rollers from jumping or the track from deviating, and ensures the smooth operation of the detection device. When the eccentric wheel 13 is reset, the spring 20 releases its elastic force, pushing the pressure ring 16 and the roller mounting seat back to the initial position, ensuring that the roller 18 is reset accurately. Meanwhile, the roller 19 slides down under the push of the eccentric wheel 14 and fits against the track 3, ensuring that the roller always fits well against the track.

[0026] See Figure 5 As shown, both track 1 2 and track 2 3 are mounted on the bonding plate, and a transfer rail 21 is provided at their junction for rotation. The width of transfer track 21 is the same as that of track 2 and track 3; Initially, transfer track 21 is as follows Figure 5 As shown, it is arranged along the direction of track 2 to facilitate the rolling of roller 18. Then, by rotating the transfer rail 21, it is arranged along the direction of the second track 3, so that the second roller 19 can roll through.

[0027] See Figure 1 As shown, one end of the test frame 1 is connected to two flexible suction cups 5 via telescopic units. The flexible suction cups 5 are fixed to the building body by vacuum pump. After the test frame 1 moves to the target detection position, the telescopic unit applies an appropriate abutment force to the flexible suction cup 5 to keep it in a close fit and ensure a firm adsorption. Then, the vacuum pump is activated to generate negative pressure inside the flexible suction cup 5. After the flexible suction cup 5 comes into close contact with the outer wall of the building, it generates an adsorption force. Through its internal elastic material, it adapts to the slight unevenness of the building surface. The flexible suction cup 5 and the building body form a point adsorption support, which prevents the test frame 1 from shaking during the detection process and improves the accuracy of image acquisition and crack identification.

[0028] When in use, this invention utilizes a liftable lifting plate 4, a rotating detection component, and two sets of marking units to detect multiple components such as shear walls, beams, columns, and floor slabs, making it more versatile. During detection, the sliding push block 26 pushes against the moving block 25, causing the moving block 25 to extend outwards. Meanwhile, a corresponding marking element 33 contacts the building structure, allowing the piston seat 32 to move into the top surface of the moving block 25. This allows the marking liquid inside the top surface of the moving block 25 to seep into the marking element 33 through several small holes. The marking element 33 then quickly marks the starting point of the crack in the building structure, while another marking element 33 in the same marking unit marks the end of the crack area. This automatically creates a visual mark in the crack area, facilitating quick location of the crack position, range, and repair area for subsequent personnel, saving time spent on manual searching and comparison. The starting and ending points are marked according to the detection signals, ensuring that the marking range covers the entire defect area. By setting up a rolling switching unit and a transfer rail 21, the positions of eccentric wheel 13 and eccentric wheel 24 change due to the rotation of the drive shaft. Roller 2 19 is exposed outward and enters into track 2 3. Through the rotation of the transfer rail 21, it is arranged along the direction of track 2 3, which facilitates the rolling of roller 2 19. It can selectively extend according to the operation stage to realize the switching of the sliding track. It can accurately detect different positions of the building body along track 2 3 without the need for separate correction and alignment, effectively improving the accuracy and efficiency of crack detection and eliminating the need for additional manual straightening or laser positioning mechanisms. After the test frame 1 is moved to the target detection position, the telescopic unit applies an appropriate abutment force to the flexible suction cup 5 to keep it in a close fit and ensure a firm adsorption. Then, the vacuum pump is started to generate negative pressure inside the flexible suction cup 5. After the flexible suction cup 5 comes into close contact with the outer wall of the building, it generates an adsorption force. Through its internal elastic material, it adapts to the slight unevenness of the building surface. The flexible suction cup 5 and the building body form a point adsorption support, which prevents the test frame 1 from shaking during the detection process and improves the accuracy of image acquisition and crack identification.

[0029] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A detection device for detecting cracks in the main structure of a building, characterized in that: The system includes a second track (3) arranged parallel to the main body of the building, a first track (2) arranged perpendicular to the main body of the building, a U-shaped test frame (1) slidably arranged on the first track (2), and lifting plates (4) raised and lowered on both inner walls of the test frame (1). The same rotatable detection component is vertically slidably arranged on the inner walls of the two lifting plates (4). The detection assembly includes a rotatable rotating plate (6), and a base plate (8) is installed on the inner wall end of the two rotating plates (6). An electric push rod (9) is installed on the surface of the base plate (8). The pushing end of the electric push rod (9) is connected to a detection box (7) that slides along the rotating plate (6). The detection box (7) is open on the side facing the main building. The inside of the detection box (7) is equipped with a slider (22) that slides horizontally. The slider (22) is connected to a detection seat (23) via a support rod. A detection module (10) is installed in the middle of the detection seat (23). Two sets of marking units are provided on the outside of the detection module (10). Each marking unit includes two moving blocks (25) that are lifted and installed in the detection seat (23) and arranged symmetrically on the axis. The inner cavity of the detection seat (23) is provided with a push block (26), and the push block (26) is abutted against the corresponding moving block (25). Each moving block (25) has a piston seat (32) movably connected to its top surface via an elastic element. The upper end of the piston seat (32) is provided with a marker (33), and the surface of the piston seat (32) is provided with several small holes for the passage of the marking liquid. A second spring (34) is sleeved on the outside of the moving block (25), and the end of the second spring (34) is fixed to one inner wall of the detection seat (23); The inside of the detection seat (23) is equipped with an adjustment unit for controlling the push blocks (26) in each group of marking units to move simultaneously or at different times.

2. The detection device for detecting cracks in the main structure of a building according to claim 1, characterized in that, The inner cavity of the detection seat (23) is provided with a liquid storage tank (24), and the discharge end of the liquid storage tank (24) is provided with a solenoid valve and is connected to the interior of the moving block (25) through a hose.

3. The detection device for detecting cracks in the main structure of a building according to claim 1, characterized in that, The adjustment unit includes a bevel gear (27) driven by a servo motor. The inside of the detection seat (23) is provided with four concentric slide rails (28), and the extension lines of two adjacent slide rails (28) are arranged perpendicularly. Each slide rail (28) is slidably provided with a vertical plate (31), and a bevel gear (30) that meshes with bevel gear one (27) is rotatably installed on the vertical plate (31). Each bevel gear two (30) has a threaded push rod (29) that is connected to the corresponding push block (26) through its internal thread.

4. The detection device for detecting cracks in the main structure of a building according to claim 1, characterized in that, A slide block (11) is slidably provided in the track on the inner wall of the lifting plate (4), and the slide block (11) is rotatably arranged with the rotating plate (6); Two lifting cylinders (12) that move simultaneously are installed in the cavity at the bottom of the test frame (1). Each lifting cylinder (12) is fixed to the bottom surface of the corresponding side lifting plate (4).

5. A detection device for detecting cracks in the main structure of a building according to claim 1, characterized in that, The test frame (1) is equipped with a rolling switching unit in the bottom cavity. The rolling switching unit includes an eccentric wheel one (13) and an eccentric wheel two (14) that are fixedly connected to the drive shaft. After the eccentric wheel one (13) rotates half a turn, it coincides with the eccentric wheel two (14). The bottom of the eccentric wheel one (13) is provided with a roller one (18) that rolls along the track one (2). The bottom of the eccentric wheel two (14) is provided with a roller two (19) that rolls along the track two (3).

6. A detection device for detecting cracks in the main structure of a building according to claim 5, characterized in that, A fixing plate is provided below the drive shaft, and a buffer reset unit for use by roller one (18) and roller two (19) is provided on the fixing plate; The buffer reset unit includes a buffer seat (15). The mounting bases of roller one (18) and roller two (19) are provided with pressure rings (16) that slide along the buffer seat (15) for a limited distance. A spring one (20) is sleeved on the outside of the pressure ring (16). One end of the spring one (20) is fixed to the fixing plate. The bottom surface of the fixed part is provided with a limiting seat (17) that slides and fits against the mounting bases of roller one (18) and roller two (19).

7. A detection device for detecting cracks in the main structure of a building according to claim 1, characterized in that, Both track one (2) and track two (3) are installed on the bonding plate, and a transfer rail (21) is provided at their junction. The transfer track (21) has the same width as the track on track one (2) and track two (3).

8. A detection device for detecting cracks in the main structure of a building according to claim 1, characterized in that, The test frame (1) is connected to two flexible suction cups (5) at both ends of one side via telescopic units. The flexible suction cups (5) are fixed to the building body by vacuum pump.

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