Unmanned aerial vehicle surveying device for steel structure building

Abstract

The invention provides an unmanned aerial vehicle surveying device for a steel structure building, and belongs to the technical field of unmanned aerial vehicle surveying devices for steel structure constructions.The unmanned aerial vehicle surveying device structurally comprises an unmanned aerial vehicle body, the unmanned aerial vehicle body is movably sleeved with a surveying device in a clamped mode, the unmanned aerial vehicle body is electrically connected with the surveying device, and the surveying device comprises a rotating frame set; a fiber guide electromagnetic seat group is arranged in the middle of the left side face of the rotating frame group, an external tension weakening mechanism is transversely and electromagnetically connected to the left side face of the fiber guide electromagnetic seat group, a surveying head mechanism is transversely arranged on the left side face of the external tension weakening mechanism, and a spring power coil is electrically connected between the rotating frame group and the fiber guide electromagnetic seat group; the surveying operation of the unmanned aerial vehicle surveying device can adapt to various wind and weather, the surveying effect is improved, manual high-altitude operation is effectively replaced, the high-altitude operation risk is completely eradicated, and time and labor are saved.

Description

Technical Field

[0001] The present invention relates to a drone survey device for steel structure buildings, belonging to the technical field of drone survey devices for steel structure buildings. Background Art

[0002] Generally, a steel structure building is composed of a steel frame coated with a functional coating, and the coating needs to be regularly maintained and applied to ensure the safety of the overall steel frame; moreover, if the thickness of the coating is relatively thin, the functional effect is relatively weak, and it is easy to damage the steel at the bottom.

[0003] When surveying the film thickness of the coating on high-rise steel structures, the existing technology is to assist workers in high-altitude operations for surveying and measurement through an external lifting platform. In some environments, the external lifting platform cannot be used, and a hanging basket needs to be used. Both of the above two auxiliary devices require workers to conduct high-altitude surveying and measurement operations, which are time-consuming and laborious, and have high risks. In view of the above deficiencies, the present invention proposes a drone for measuring the film thickness of coatings on high-rise steel structures. Summary of the Invention

[0004] Aiming at the deficiencies existing in the prior art, the purpose of the present invention is to provide a drone survey device for steel structure buildings to solve the existing problems.

[0005] To achieve the above purpose, the present invention is realized through the following technical solutions: A drone survey device for steel structure buildings, its structure includes a drone main body, and a survey device is movably sleeved on the drone main body, and the drone main body is electrically connected to the survey device. The survey device includes a rotating frame group, and a fiber guiding electromagnetic seat group is arranged in the middle of the left side surface of the rotating frame group. And a lateral electromagnetic connection of an external tension weakening mechanism is arranged on the left side surface of the fiber guiding electromagnetic seat group. A survey head mechanism is arranged horizontally on the left side surface of the external tension weakening mechanism. A spring power coil is electrically connected between the rotating frame group and the fiber guiding electromagnetic seat group; The external tension weakening mechanism includes a magnetic attraction seat group and an external tension buffer assembly. A universal ball seat is connected between the magnetic attraction seat group and the external tension buffer assembly. And a reset fiber guiding group is arranged in the right cavity of the magnetic attraction seat group, and the other end of the reset fiber guiding group extends and is connected to the cavity on the left side surface of the fiber guiding electromagnetic seat group; The survey head mechanism includes an electromagnetic chuck seat, and a survey telescopic head group is horizontally sleeved in the left cavity of the electromagnetic chuck seat. And a plurality of first electromagnetic chucks are embedded along the circumferential edge of the left side surface of the survey telescopic head group in an annular array.

[0006] Further improvement is that two engaging bases movably sleeved with the rotating frame group are arranged in the middle of the front and rear sides of the drone main body.

[0007] Further improved, the rotary frame group includes a gantry, and two rotators are symmetrically arranged inside the lower end of the gantry, and a card sleeve slider that is movably engaged with the clamping base is arranged inside the two rotators.

[0008] Further improved, the fiber guiding electromagnetic seat group includes a fiber guiding seat, a circular fiber guiding sleeve groove is opened in the middle of the left side surface of the fiber guiding seat, and a second electromagnetic chuck is embedded in the middle of the bottom of the circular fiber guiding sleeve groove, and a tension sensor sleeve groove is opened in the middle of the second electromagnetic chuck.

[0009] Further improved, the magnetic suction seat group includes a horizontal seat, a circular magnetic suction block is arranged on the right side surface of the horizontal seat, a winder sleeve groove is opened in the middle of the right side surface of the horizontal seat, a fiber guiding wire through hole is opened in the middle of the right side surface of the circular magnetic suction block, the circular magnetic suction block is made of iron, and the fiber guiding wire through hole is in a horn-shaped structure.

[0010] Further improved, the external tension buffer assembly includes a single-sided stretching structure, and the single-sided stretching structure is composed of a circular fixing plate, a circular stretching plate, a plurality of stretching sliding rods and a plurality of first spring sleeves. A plurality of stretching springs are connected to the peripheral edge of the right side surface of the circular stretching plate in an annular array, and the other ends of the stretching springs extend and are fixedly connected to the peripheral circle of the surface of the magnetic suction seat group in an annular array.

[0011] Further improved, the reset fiber guiding group includes a winder main body, a fiber guiding steel wire rope is wound on the winder main body, and the other end of the fiber guiding steel wire rope is connected with a tension sensor, and the tension sensor is fixedly installed in the middle of the bottom of the tension sensor sleeve groove.

[0012] Further improved, a survey head movable groove is opened in the middle of the left side surface of the electromagnetic chuck seat, and a plurality of electromagnetic chuck sleeve grooves are opened in the peripheral edge of the left side surface of the electromagnetic chuck seat in an annular array.

[0013] Further improved, the survey telescopic head group includes a bracket, a telescopic device is horizontally arranged in the middle of the bracket, a pressure sensor is arranged on the left side surface of the telescopic device, and a survey pressing mechanism and a survey instrument main body are arranged on the left side surface of the pressure sensor; The survey pressing mechanism is composed of an annular frame and a pressing soft disk in fit, a first through hole is opened through the middle of the annular frame, a second through hole is opened through the middle of the pressing soft disk, the pressing soft disk is in a horn shape and is made of rubber; The left side surface of the survey instrument main body is retracted 2 mm from the left side surface of the pressing soft disk. When the telescopic device extends to drive the pressing soft disk to press against the surface of the steel structure, when the pressure sensor senses a limited pressure value, the pressing soft disk deforms to be vertically aligned with the left side surface of the survey instrument main body, so that the left side surface of the survey instrument main body gently adheres to the surface of the steel structure for survey operation.

[0014] Further improvements are that the drone body and the surveying instrument body are based on existing technologies, and the structures will not be elaborated one by one here.

[0015] Further improvements are that there is an electrical connection between the rotating frame group and the fiber guiding electromagnetic seat group.

[0016] Further improvements are that there is an electrical connection between the external tensile force weakening mechanism and the surveying head mechanism.

[0017] Further improvements are that the combination of the magnetic suction seat group, the universal ball seat, and the external tensile force buffer assembly constitutes a universal angle self-adaptive adjustment seat.

[0018] The beneficial effects of the present invention are as follows: The present invention provides a drone surveying device for steel structure buildings. Through the movable clamping design of the drone body and the surveying device, it is convenient for storage. The structural combination design of the rotating frame group, the fiber guiding electromagnetic seat group, the external tensile force weakening mechanism, the surveying head mechanism, and the spring power coil constitutes a surveying device. Among them, the universal angle self-adaptive adjustment seat composed of the magnetic suction seat group, the universal ball seat, and the external tensile force buffer assembly can assist the surveying head mechanism to make self-adaptive angle fine-tuning when abutting against the surface of the steel structure, making it easier for the surveying head mechanism to horizontally abut against the surface of the steel structure. Moreover, the universal angle self-adaptive adjustment seat can also weaken the oblique stress and external tensile stress when the drone body is shaken by the wind, preventing the surveying head mechanism from being electromagnetically adsorbed and detached due to the externally transmitted tensile stress. The surveying head mechanism has the function of electromagnetically adsorbing the surface of the steel structure and simulates the manual light attachment of workers for surveying, making the light attachment force of the surveying instrument body controllable. The reset fiber guiding group plays a role in fiber guiding connection after canceling the detached state of the electromagnetic connection between the magnetic suction seat group and the fiber guiding electromagnetic seat group, facilitating the subsequent rapid alignment operation when the drone body makes a reset connection. In addition, the fiber guiding steel wire rope on the reset fiber guiding group can be adjusted to a soft state, which can provide an external tensile buffer distance again between the drone body and the surveying head mechanism, so that when the drone body has a large shaking displacement caused by strong winds, the surveying head mechanism can also be prevented from being transmitted to the external tensile stress. The auxiliary cooperation of the above functions enables the surveying operation of the drone surveying device to adapt to various wind weather conditions, improves the surveying effect, effectively replaces manual high-altitude operations, eliminates high-altitude operation risks, and saves time and effort. Description of the Drawings

[0019] Figure 1 Schematic diagram of the drone surveying device for steel structure buildings of the present invention for surveying the horizontal plane of the steel structure; Figure 2 Schematic diagram of the drone surveying device for steel structure buildings of the present invention for surveying the inclined plane of the steel structure; Figure 3 Schematic diagram of the structure of the surveying device of the present invention; Figure 4 Right view of the rotating frame group of the present invention; Figure 5 Schematic diagram of the fiber guiding electromagnetic seat group of the present invention; Figure 6 Schematic diagram of the external tensile force weakening mechanism of the present invention; Figure 7 Schematic diagram of the survey head mechanism of the present invention; Figure 8 Schematic diagram of the magnetic attraction seat group of the present invention; Figure 9 Schematic diagram of the external tensile force buffer assembly of the present invention; Figure 10 Schematic diagram of the reset fiber guiding group of the present invention; Figure 11 Schematic diagram of the electromagnetic chuck seat of the present invention; Figure 12 Schematic diagram of the deployed structure of the survey telescopic head group of the present invention. Detailed implementation manners

[0020] In order to make the technical means, creative features, achieved purposes and effects of the present invention easy to understand, the present invention will be further described below in conjunction with the detailed implementation manners.

[0021] Please refer to Figures 1 - 12 , the present invention provides an unmanned aerial vehicle survey device for steel structure buildings: its structure includes a UAV main body 1, and a survey device 2 is movably sleeved on the UAV main body 1, and the UAV main body 1 is electrically connected to the survey device 2. The survey device 2 includes a rotating frame group 21, and a fiber guiding electromagnetic seat group 22 is arranged in the middle of the left side surface of the rotating frame group 21, and an external tensile force weakening mechanism 23 is horizontally electromagnetically connected to the left side surface of the fiber guiding electromagnetic seat group 22. A survey head mechanism 24 is horizontally arranged on the left side surface of the external tensile force weakening mechanism 23. A spring power coil 25 is electrically connected between the rotating frame group 21 and the fiber guiding electromagnetic seat group 22. The external tensile force weakening mechanism 23 includes a magnetic attraction seat group 231 and an external tensile force buffer assembly 233. A universal ball seat 232 is connected between the magnetic attraction seat group 231 and the external tensile force buffer assembly 233. A reset fiber guiding group 234 is arranged in the right cavity of the magnetic attraction seat group 231, and the other end of the reset fiber guiding group 234 extends and is connected to the left cavity of the left side surface of the fiber guiding electromagnetic seat group 22. The survey head mechanism 24 includes an electromagnetic chuck seat 241, and a survey telescopic head group 242 is horizontally sleeved in the left cavity of the electromagnetic chuck seat 241, and a plurality of first electromagnetic chucks 243 are annularly arrayed and embedded along the circumferential edge of the left side surface of the survey telescopic head group 242.

[0022] Two engaging bases 11 movably sleeved with the rotating frame group 21 are arranged in the middle of the front and rear sides of the UAV main body 1.

[0023] The rotary frame group 21 includes a gantry 211, and two rotators 212 are symmetrically arranged inside the lower end of the gantry 211, and a clamping sleeve slider 213 that is movably clamped with the clamping base 11 is arranged inside the two rotators 212.

[0024] The fiber guiding electromagnetic seat group 22 includes a fiber guiding seat 221, a circular fiber guiding sleeve groove 222 is formed in the middle of the left side surface of the fiber guiding seat 221, and a second electromagnetic chuck 223 is embedded in the middle of the bottom of the circular fiber guiding sleeve groove 222, and a tension sensor sleeve groove 224 is formed in the middle of the second electromagnetic chuck 223.

[0025] The magnetic suction seat group 231 includes a cross seat 2311, a circular magnetic suction block 2312 is arranged on the right side surface of the cross seat 2311, a winder sleeve groove 2313 is formed in the middle of the right side surface of the cross seat 2311, a fiber guiding wire through hole 2314 is formed in the middle of the right side surface of the circular magnetic suction block 2312, the circular magnetic suction block 2312 is made of iron, and the fiber guiding wire through hole 2314 is in a horn-shaped structure.

[0026] The external tension buffer assembly 233 includes a single-sided stretching structure, and the single-sided stretching structure is composed of a circular fixing plate 2331, a circular stretching plate 2332, a plurality of stretching sliding rods 2333 and a plurality of first springs 2334 sleeved together. A plurality of stretching springs 2335 are connected to the peripheral edge of the right side surface of the circular stretching plate 2332 in an annular array, and the other ends of the stretching springs 2335 extend and are fixedly connected to the peripheral circle of the surface of the magnetic suction seat group 231 in an annular array.

[0027] The reset fiber guiding group 234 includes a winder main body 2341, a fiber guiding steel wire rope 2342 is wound on the winder main body 2341, and the other end of the fiber guiding steel wire rope 2342 is connected to a tension sensor 2343, and the tension sensor 2343 is fixedly installed in the middle of the bottom of the tension sensor sleeve groove 224.

[0028] A survey head movable groove 2411 is formed in the middle of the left side surface of the electromagnetic chuck seat 241, and a plurality of electromagnetic chuck sleeve grooves 2412 are formed in the peripheral edge of the left side surface of the electromagnetic chuck seat 241 in an annular array.

[0029] The survey telescopic head group 242 includes a bracket 2421. A telescopic device 2422 is horizontally arranged in the middle of the bracket 2421. A pressure sensor 2423 is arranged on the left side of the telescopic device 2422. A survey pressing mechanism 2424 and a survey instrument main body 2425 are arranged on the left side of the pressure sensor 2423. The survey pressing mechanism 2424 is formed by fitting an annular frame 24241 and a pressing flexible disk 24242. A first through hole 24243 is formed through the middle of the annular frame 24241. A second through hole 24244 is formed through the middle of the pressing flexible disk 24242. The pressing flexible disk 24242 is in a horn shape and is made of rubber. The left side of the survey instrument main body 2425 is retracted 2 mm from the left side of the pressing flexible disk 24242. When the telescopic device 2422 extends to drive the pressing flexible disk 24242 to press against the surface of the steel structure, when the pressure sensor 2423 senses a specified pressure value, the pressing flexible disk 24242 deforms to be vertically aligned with the left side of the survey instrument main body 2425, so that the left side of the survey instrument main body 2425 gently adheres to the surface of the steel structure for survey operation.

[0030] Working principle: During use, through the snap fit of the snap base 11 and the snap sleeve slider 213, the whole survey device 2 is sleeved on the UAV main body 1, and the electrical signal is connected. Then, the UAV main body 1 is operated to fly to the high-position steel structure. Then, check whether the surface of the steel structure is a horizontal plane or an inclined plane. The rotating device 212 on the rotating frame group 21 drives the gantry 211 to adjust the angle for adaptation. The maximum adjustment angle of the rotating frame group 21 is 360°. Then, the UAV main body 1 moves towards the steel structure to be surveyed, so that each first electromagnetic chuck 243 on the survey head mechanism 24 abuts against the surface of the steel structure and is magnetically connected and fixed. During the abutting process, since it is difficult for the UAV main body 1 to maintain a completely aligned state during abutting, it will abut at a slightly inclined angle. However, through the universal angle self-adaptive adjustment seat composed of the magnetic suction seat group 231, the universal ball seat 232, and the external tension buffer assembly 233, the universal angle self-adaptive adjustment seat can cooperate to assist in realizing the self-adaptive adjustment of the survey head mechanism 24 to be horizontally abutted against the surface of the steel structure. After the survey head mechanism 24 is abutted and magnetically adsorbed, the UAV main body 1 first performs a hovering operation, and then the telescopic device 2422 extends. Due to the initial setting that the left side of the survey instrument main body 2425 is retracted 0.2 mm from the left side of the pressing flexible disk 24242, when the telescopic device 2422 extends to drive the pressing flexible disk 24242 to press against the surface of the steel structure, when the pressure sensor 2423 senses a specified pressure value, the pressing flexible disk 24242 will deform to be vertically aligned with the left side of the survey instrument main body 2425, so that the left side of the survey instrument main body 2425 gently adheres to the surface of the steel structure for survey operation, similar to the manual operation of the survey staff to gently adhere the survey instrument main body 2425 to the surface of the steel structure for survey operation.

[0031] In addition, when surveying in breezy weather, after the drone body 1 is hovering, the breeze causes the drone body 1 to shake and displace at a small interval. Through the automatic universal swing adjustment function of the universal angle adaptive adjustment seat composed of the magnetic seat group 231, the universal ball seat 232, and the external tension buffer assembly 233, and the unilateral buffering stretching of the unilateral stretching structure composed of the circular fixed plate 2331, the circular stretching plate 2332, multiple stretching slide rods 2333 and multiple first springs 2334, the lateral stress and oblique stress transmitted to the survey head mechanism 24 when the drone body 1 shakes can be reduced to the greatest extent, so that the electromagnetic adsorption of the survey head mechanism 24 on the structural surface will not be pulled away.

[0032] In addition, when surveying in windy weather, after the drone body 1 hovers, the strong wind will cause a large shaking displacement interval on the drone body 1, and the shaking displacement interval will be greater than the maximum buffer stretching interval of the unilateral tensile structure, so the conducted outward tensile stress on the survey head mechanism 24 will be very strong, making the electromagnetic adsorption of the survey head mechanism 24 at risk of being pulled out. At this time, the fiber-guided steel wire rope 2342 can be released through the reel body 2341, and the electromagnetic connection between the second electromagnetic suction cup 223 and the circular magnetic suction block 2312 is canceled synchronously, and the drone body 1 is displaced in the opposite direction of the steel structure, so that the fiber-guided electromagnetic seat group 22 and the magnetic seat group 231 are completely separated. When the tension sensor 2343 senses that there is no tension value, the fiber-guided steel wire rope 2342 is in a loose state, and the spring power supply coil 25 is in a stretched and extended state. Refer to the attached Figure 1 , 2 In this state, when strong wind causes the UAV body 1 to shake and displace to a large extent, the loose state of the fiber-pulling wire rope 2342 provides a large external pulling buffer distance, so that the UAV body 1 will not transmit outward pulling stress to the survey head mechanism 24.

[0033] When the survey is completed, the reel body 2341 reels the fiber guide wire rope 2342, which will move the UAV body 1 toward the magnetic seat group 231, and the UAV body 1 will also make a coordinated displacement. When the tension sensor 2343 senses a strong tension, it can be determined that the circular magnetic block 2312 and the second electromagnetic suction cup 223 are in a state of being against each other and are electromagnetically connected. The fiber guide tension after the reset fiber guide group 234 is fully retracted can strengthen and fix the electromagnetic connection between the circular magnetic block 2312 and the second electromagnetic suction cup 223. Finally, each first electromagnetic suction cup 243 cancels the electromagnetic adsorption, and the survey telescopic head group 242 synchronously retracts and resets, the UAV body 1 flies away, and the survey operation is completed.

[0034] The foregoing has shown and described the basic principles, main features and advantages of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and without departing from the spirit or basic features of the present invention, the present invention can be implemented in other specific forms. Therefore, in any regard, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention. Any reference signs in the claims should not be construed as limiting the claims involved.

[0035] In addition, it should be understood that although this specification is described in terms of embodiments, not every embodiment only contains an independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A UAV surveying device for steel structure buildings, comprising a UAV main body, a surveying device is provided on the movable sleeve of the UAV main body, and the UAV main body is electrically connected to the surveying device, characterized in that: The surveying device comprises a rotating frame group, and a fiber-pulling electromagnetic seat group is arranged in the middle of the left side of the rotating frame group, and an external tension reduction mechanism is electromagnetically connected to the left side of the fiber-pulling electromagnetic seat group, and a surveying head mechanism is arranged laterally on the left side of the external tension reduction mechanism, and a spring power supply coil is electrically connected between the rotating frame group and the fiber-pulling electromagnetic seat group; The external tension reduction mechanism includes a magnetic seat group and an external tension buffer assembly, a universal ball seat is connected between the magnetic seat group and the external tension buffer assembly, and a reset fiber guide assembly is arranged in the cavity on the right side of the magnetic seat group, and the other end of the reset fiber guide assembly extends and is connected to the cavity on the left side of the fiber guide electromagnetic seat group; The surveying head mechanism comprises an electromagnetic suction cup seat, and a surveying telescopic head group is transversely sleeved in the left cavity of the electromagnetic suction cup seat, and a plurality of first electromagnetic suction cups are embedded in a circular array around the left side surface of the surveying telescopic head group.

2. The unmanned aerial vehicle survey device for steel structure buildings according to claim 1 is characterized in that: Two clamping bases for engaging with movable clamping sleeves of the rotating frame assembly are arranged in the middle of the front and rear sides of the drone body.

3. The unmanned aerial vehicle surveying device for steel structure buildings according to claim 2 is characterized in that: The rotating frame assembly comprises a gantry, and two rotators are symmetrically arranged on the inner side of the lower end of the gantry, and a clamping sleeve sliding block movably engaged with the engaging base is arranged on the inner side of the two rotators.

4. The unmanned aerial vehicle surveying device for steel structure buildings according to claim 3 is characterized by: The fiber-leading electromagnetic seat assembly includes a fiber-leading seat, and a circular fiber-leading sleeve groove is opened in the middle of the left side of the fiber-leading seat, and a second electromagnetic suction cup is embedded in the middle of the groove bottom of the circular fiber-leading sleeve groove, and a tension sensor sleeve groove is opened in the middle of the second electromagnetic suction cup.

5. The unmanned aerial vehicle surveying device for steel structure buildings according to claim 4 is characterized in that: The magnetic seat group includes a horizontal seat, and a circular magnetic block is arranged on the right side of the horizontal seat, and a reel sleeve groove is opened in the middle of the right side of the horizontal seat, and a fiber lead wire opening is opened in the middle of the right side of the circular magnetic block. The circular magnetic block is made of iron, and the fiber lead wire opening is a trumpet-shaped structure.

6. The unmanned aerial vehicle surveying device for steel structure buildings according to claim 5 is characterized by: The external tension buffer component includes a unilateral stretching structure, and the unilateral stretching structure is composed of a circular fixed plate, a circular stretching plate, multiple stretching slide rods and multiple first springs. The right side of the circular stretching plate is connected to multiple stretching springs in a circular array, and the other end of each stretching spring extends and is fixed to the surface of the magnetic seat group in a circular array.

7. The unmanned aerial vehicle surveying device for steel structure buildings according to claim 6 is characterized by: The resetting fiber guide group includes a reel body, and a fiber guide wire rope is wound on the reel body, and the other end of the fiber guide wire rope is connected to a tension sensor, and the tension sensor is fixedly installed in the middle of the bottom of the tension sensor sleeve groove.

8. The unmanned aerial vehicle surveying device for steel structure buildings according to claim 7, characterized in that: A survey head movable groove is provided in the middle of the left side of the electromagnetic suction cup seat, and a plurality of electromagnetic suction cup sleeve grooves are provided in a circular array along the circumference of the left side of the electromagnetic suction cup seat.

9. The unmanned aerial vehicle surveying device for steel structure buildings according to claim 8, characterized in that: The survey telescopic head group includes a bracket, and a telescope is horizontally arranged in the middle of the bracket, and a pressure sensor is arranged on the left side of the telescope, and a survey pressing mechanism and a survey instrument body are arranged on the left side of the pressure sensor; The surveying and pressing mechanism is composed of an annular frame and a pressing soft disk, a first opening is opened through the middle of the annular frame, a second opening is opened through the middle of the pressing soft disk, and the pressing soft disk is trumpet-shaped and made of rubber; The left side of the survey instrument body is retracted 2mm from the left side of the pressing disk. When the telescopic device extends to drive the pressing disk to press against the surface of the steel structure, when the pressure sensor senses a limited pressure value, the pressing disk is deformed and vertically aligned with the left side of the survey instrument body, allowing the left side of the survey instrument body to lightly touch the surface of the steel structure for surveying operations.

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