A device for detecting cracks in underwater buildings

Abstract

The invention relates to the technical field of underwater building crack detection, and discloses an underwater building crack detection device, comprising a detection rod, a hand-held groove, an extrusion plate, and an installation box, wherein the detection rod is installed on the top of the installation box, and the bottom end of the detection rod extends to the inside of the installation box, the hand-held groove is located on the left and right sides of the installation box, two groups of extrusion plates are symmetrically arranged on both sides of the top surface of the installation box, and one end of the two groups of extrusion plates is respectively connected to the detection rod; the underwater building crack detection device is inserted into the crack by shortening the distance of the upper end of the detection rod, and under the elastic force of an elastic mechanism, the upper ends of the detection rod are close to the inner wall of the crack, and the straight-line distance of the opening and closing is the crack width, and then the sliding distance of the sliding rod is measured by a winding mechanism, and the width of the crack is detected by a physical method to prevent the underwater environment from affecting the line of sight and stability of scanning.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater building crack detection, and more specifically, to an underwater building crack detection device. Background Art

[0002] The underwater building crack detection utilizes the crack meter method, which is installed parallel to the building surface and perpendicular to the crack. Therefore, there is no need to conduct manual inspection underwater each time. It is mainly used for the inspection of concrete such as underwater bridges and tunnel walls. Underwater buildings can automatically perform inspections when they are impacted and expanded or cracks occur, and the inspection data can be transmitted to the instrument, avoiding the inconvenience of manual inspection underwater.

[0003] However, when using the crack meter method for detection, the change in the amount of crack expansion after it is generated and when the crack first appears, its width needs to be detected using laser scanning. The water is relatively turbid, and the laser scanning detection method is easy to block the line of sight. In addition, personnel operating underwater will swing under the movement of the water flow, and the detection effect is poor. The crack cannot be stably detected. When the depth of the crack is different, the width of each position of the crack will be different. When the width is larger at a deeper position, it is difficult for the detection device to enter for detection and it will be blocked by the smaller cracks on the outside, making it difficult for the detection device to penetrate deep into the crack. Summary of the invention

[0004] The present invention provides an underwater building crack detection device, which solves the technical problem in the related art that the underwater is relatively turbid and the line of sight of laser scanning detection is easily blocked.

[0005] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0006] A device for detecting cracks in underwater buildings, comprising a detection rod, a hand-held groove, an extrusion plate, and an installation box, wherein the detection rod is installed on the top of the installation box, and the bottom end of the detection rod extends to the inside of the installation box, the hand-held groove is located on the left and right sides of the installation box, and two groups of extrusion plates are symmetrically arranged on both sides of the top surface of the installation box, and one end of the two groups of extrusion plates is respectively connected to the detection rod;

[0007] The interior of the installation box is provided with an elastic mechanism, a winding mechanism, a sliding rod, a sliding groove, and an installation groove;

[0008] The top of the installation box is provided with an installation groove, the front and rear ends of the inner wall of the installation groove are symmetrically provided with slide grooves, the same end of the two groups of slide grooves are commonly provided with a slide rod, the bottom end of the elastic mechanism is hinged to the bottom surface of the inside of the installation groove, the top end of the elastic mechanism is sleeved on the outside of the slide rod, the winding mechanism is installed in the middle of the top of the installation groove, and the output end of the winding mechanism is connected to a group of slide rods;

[0009] The bottom end of the detection rod is sleeved on the outer side of the sliding rod, and the detection rod is driven to follow the displacement through the displacement of the sliding rod.

[0010] As a further optimization scheme of the present invention, the bottom of the extrusion plate is slidably connected to the top of the mounting box, and a locking mechanism is provided between the top of the extrusion plate and the mounting box. The extrusion plate is positioned at the top of the mounting box through the locking mechanism, thereby positioning the detection rod.

[0011] As a further optimization scheme of the present invention, the winding mechanism includes a support ring, a scale strip, a winding roller, and a coil spring. Support rings are fastened to the middle parts of the front and rear ends of the inner wall of the installation groove, and coil springs are arranged on the inner sides of the two groups of support rings. Winding rollers are commonly arranged at the inner ends of the two groups of coil springs. A scale strip is wound around the outer side of the winding roller, and the other end of the scale strip is fixedly connected to a group of sliding rods. Positioning ports are arranged at the top end of the outer side of the support ring, and counting scales are arranged on both sides of the scale strip.

[0012] As a further optimization solution of the present invention, both the front and rear ends of the installation box are provided with observation windows corresponding to the positioning openings, and magnifying lenses are embedded in the observation windows.

[0013] As a further optimization scheme of the present invention, the winding roller includes a rotating ring, a friction ring, and a connecting rod. The rotating ring is sleeved on the outside of the connecting rod. The rotating ring is a cylindrical structure, and the diameter of the middle part of the rotating ring is larger than the diameter of its two ends. The friction ring fits in the middle part of the outer side of the rotating ring.

[0014] As a further optimization scheme of the present invention, the elastic mechanism includes an inner sleeve rod, a tube sleeve, a hinge seat, and a spring. The hinge seat is staggered and distributed at the bottom of the installation groove, and the bottom end of the inner sleeve rod is hinged to the hinge seat. The top end of the inner sleeve rod is sleeved with a tube sleeve, and a positioning spring is jointly sleeved between the outer side of the tube sleeve and the outer side of the inner sleeve rod, and the top end of the tube sleeve is sleeved on the outer side of the sliding rod.

[0015] As a further optimization scheme of the present invention, the detection rod includes a lever arm, a fixed ball, an adjusting rod, and a hinge shaft. The two groups of lever arm rods are cross-hinged in an "X" shape, and a hinge shaft is commonly provided at the hinge of the two groups of lever arm rods. The lever arm rods are each provided with an adjusting rod near the top of the hinge shaft, and the top of the adjusting rod is each provided with a fixed ball.

[0016] As a further optimization scheme of the present invention, the bottom end of the lever arm extends to the inside of the installation slot and is hinged to the slide rod. The two groups of slide rods slide and displace inside the slide slot, thereby driving the two groups of lever arms to be hinged and displaced in a scissors-like manner.

[0017] As a further optimization scheme of the present invention, the adjusting rod includes a connecting rod, a locking ring, a hollow rod, a support rod, and a limit block. The connecting rod is connected to the lever arm rod, a support rod is arranged at the top end of the connecting rod, a locking ring is sleeved on the outer side of the support rod, a hollow rod is sleeved on the outer side of the locking ring, and the hollow rod is sleeved on the outer side of the support rod as a whole, and a limit block is jointly arranged between the inner side of the hollow rod and the locking ring.

[0018] As a further optimization scheme of the present invention, the length of the two groups of lever arms below the hinge axis is L2, the sum of the length of the two groups of lever arms above the hinge axis and the overall length of the adjusting rod is L1, the straight-line distance between the two groups of fixed balls is D1, and the straight-line distance between the bottom ends of the two groups of lever arms is D2. It can be deduced from the cosine theorem that D1 / D2=L1 / L2.

[0019] The beneficial effects of the present invention are:

[0020] 1. The present invention shortens the distance of the upper end of the detection rod and inserts it into the crack. Under the elastic force of the elastic mechanism, the two sides of the upper end of the detection rod are close to the inner wall of the crack, and the straight-line distance of its opening and closing is the crack width. Then, the sliding distance of the slide rod is measured by the winding mechanism, and under the elastic force of the coil spring, the scale bar follows the movement of the slide rod to be stretched. At the same time, the scale bar is limited by the roller outside the installation groove. The size on the scale bar is observed through the positioning port through the observation window, and the width of the crack is detected by a physical method to prevent the underwater environment from affecting the line of sight and stability of the scanning.

[0021] 2. In the present invention, when the slide rod slides inward on the slide groove, the sleeve in the elastic mechanism compresses the spring, causing the inner sleeve rod to rotate around the hinge seat, and then maintains the elastic force outward under the elastic force of the spring, ensuring that after the extrusion plate is released, the detection rod at the upper end of the slide rod is driven to expand the detection, maintain the elastic force on the slide rod, and then maintain the stability of the seam width detection through the elastic force.

[0022] 3. The present invention manually rotates the hollow rod to disengage the limit block from the blocking engagement of the side of the locking ring, and then pulls the hollow rod to make the plane side of the locking ring translate from the limit block to the position of another hollow rod for engagement and limiting, and then extends the adjusting rod. By extending the adjusting rod, the distance between the fixed balls becomes longer, and the distance of the force arm rod is observed to measure the crack width, so that the adjusting rod can penetrate deep into the crack for detection, thereby avoiding the resistance end of the adjusting rod being too short and the detection depth being limited, and preventing the width of deeper cracks from being unable to be measured. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0024] Figure 2 It is a front cross-sectional view of the installation box in the present invention;

[0025] Figure 3 It is a schematic diagram of the three-dimensional structure of the winding mechanism in the present invention;

[0026] Figure 4 It is a schematic diagram of the three-dimensional structure of the winding roller in the present invention;

[0027] Figure 5 It is a schematic diagram of the three-dimensional structure of the elastic mechanism in the present invention;

[0028] Figure 6 It is a schematic diagram of the side structure of the detection rod in the present invention;

[0029] Figure 7 It is a schematic diagram of the three-dimensional structure of the adjusting rod in the present invention.

[0030] In the figure: 1. Detection rod; 2. Hand-held groove; 3. Extrusion plate; 4. Installation box;

[0031] 41. elastic mechanism; 42. winding mechanism; 43. slide bar; 44. slide slot; 45. mounting slot;

[0032] t1, support ring; t2, scale bar; t3, winding roller; t4, coil spring; t5, positioning port;

[0033] t31, rotating ring; t32, friction ring; t33, connecting rod;

[0034] a1, inner sleeve rod; a2, sleeve; a3, hinge seat; a4, spring;

[0035] w1, lever arm; w2, fixed ball; w3, adjustment rod; w4, hinge shaft;

[0036] w31, connecting rod; w32, snap ring; w33, hollow rod; w34, supporting rod; w35, limit block. DETAILED DESCRIPTION

[0037] The subject matter described herein will now be discussed with reference to example embodiments. It should be understood that the discussion of these embodiments is only to enable those skilled in the art to better understand and implement the subject matter described herein, and the functions and arrangements of the elements discussed may be changed without departing from the scope of protection of the contents of this specification. Each example may omit, replace or add various processes or components as needed. In addition, the features described relative to some examples may also be combined in other examples.

[0038] Example 1

[0039] like Figures 1 to 5As shown, an underwater building crack detection device comprises a detection rod 1, a hand-held groove 2, a squeeze plate 3, and an installation box 4. The detection rod 1 is installed on the top of the installation box 4, and the bottom end of the detection rod 1 extends to the inside of the installation box 4. The hand-held groove 2 is located on the left and right sides of the installation box 4. Two groups of squeeze plates 3 are symmetrically arranged on both sides of the top surface of the installation box 4, and one end of the two groups of squeeze plates 3 is respectively connected to the detection rod 1. The bottom of the squeeze plate 3 is slidably connected to the top of the installation box 4, and a locking mechanism is arranged between the top of the squeeze plate 3 and the installation box 4. The squeeze plate 3 is positioned on the top of the installation box 4 through the locking mechanism, thereby positioning the detection rod 1.

[0040] An elastic mechanism 41, a winding mechanism 42, a slide bar 43, a slide groove 44, and a mounting groove 45 are arranged inside the mounting box 4. The mounting groove 45 is arranged at the top of the mounting box 4. The slide grooves 44 are symmetrically arranged at the front and rear ends of the inner wall of the mounting groove 45. The same end of the two sets of slide grooves 44 is commonly provided with a slide bar 43. The bottom end of the elastic mechanism 41 is hinged to the bottom surface of the mounting groove 45. The top end of the elastic mechanism 41 is sleeved on the outside of the slide bar 43. The winding mechanism 42 is installed in the middle of the top of the mounting groove 45, and the output end of the winding mechanism 42 is connected to a set of slide bars 43.

[0041] The bottom end of the detection rod 1 is sleeved on the outside of the sliding rod 43, and the displacement of the sliding rod 43 drives the detection rod 1 to follow the displacement;

[0042] The winding mechanism 42 includes a support ring t1, a scale strip t2, a winding roller t3, and a coil spring t4. The support ring t1 is fixedly installed in the middle of the front and rear ends of the inner wall of the installation groove 45. The inner sides of the two groups of support rings t1 are provided with coil springs t4. The inner ends of the two groups of coil springs t4 are commonly provided with a winding roller t3. The outer side of the winding roller t3 is wound with a scale strip t2, and the other end of the scale strip t2 is fixedly connected to a group of sliding rods 43. The top of the outer side of the support ring t1 is provided with a positioning port t5, and both sides of the scale strip t2 are provided with counting scales. The front and rear ends of the installation box 4 are provided with observation windows corresponding to the positioning port t5, and a magnifying lens is embedded in the observation window, and the counting scale on the scale strip t2 corresponding to the positioning port t5 is read through the observation window;

[0043] The winding roller t3 includes a rotating ring t31, a friction ring t32, and a connecting rod t33. The rotating ring t31 is sleeved on the outer side of the connecting rod t33. The rotating ring t31 is a cylindrical structure, and the diameter of the middle part of the rotating ring t31 is larger than the diameter of the two ends. The friction ring t32 is fitted to the middle part of the outer side of the rotating ring t31. Two friction rings t32 are provided, and they are made of rubber and have the characteristic of large friction. The outer side of the rotating ring t31 is an arc-shaped structure, and the middle diameter is the largest, and the diameters on both sides are smaller, so that the scale bar t2 drives the rotating ring t31 to rotate when the friction ring t32 squeezes and moves, and then the arc-shaped rotating ring t31 causes the scale bar t2 to slide in an arc, and the friction of the scale bar t2 is increased by the friction ring t32, so as to prevent the scale bar t2 from folding when moving and covering the size mark on the side.

[0044] The elastic mechanism 41 includes an inner sleeve rod a1, a sleeve a2, an articulated seat a3, and a spring a4. The articulated seat a3 is staggered and distributed at the bottom of the installation groove 45, and the bottom end of the inner sleeve rod a1 is hinged to the articulated seat a3. The top end of the inner sleeve rod a1 is sleeved with a sleeve a2, and the outer side of the sleeve a2 and the outer side of the inner sleeve rod a1 are sleeved with a spring a4 for positioning and installation. The top end of the sleeve a2 is sleeved on the outer side of the slide rod 43, and the two sleeves a2 are staggered in opposite directions. Therefore, when the slide rod 43 slides inward on the slide groove 44, the sleeve a2 compresses the spring a4, so that the inner sleeve rod a1 rotates around the articulated seat a3, and then maintains the elastic force outward under the elastic force of the spring a4, ensuring that after the extrusion plate 3 is released, the detection rod 1 at the upper end of the slide rod 43 is driven to expand the detection;

[0045] The detection rod 1 includes a force arm w1, a fixed ball w2, an adjustment rod w3, and a hinge shaft w4. The two groups of force arm w1 are cross-hinged in an "X" shape, and the hinge shaft w4 is commonly provided at the hinge of the two groups of force arm w1. The force arm w1 is provided with an adjustment rod w3 at a position close to the top of the hinge shaft w4, and the top of the adjustment rod w3 is provided with a fixed ball w2.

[0046] The length of the two sets of force arms w1 below the hinge axis w4 is L2, the sum of the length of the two sets of force arms w1 above the hinge axis w4 and the overall length of the adjusting rod w3 is L1, the straight-line distance between the two sets of fixed balls w2 is D1, and the straight-line distance between the bottom ends of the two sets of force arms w1 is D2. It can be deduced from the cosine theorem that D1 / D2=L1 / L2.

[0047] The use process of the underwater building crack detection device proposed in this embodiment is as follows: the holding groove 2 holds the mounting groove 45, thereby manually pressing the squeezing plate 3 underwater, and the displacement of the squeezing plate 3 pushes the bottom ends of the two groups of force arm rods w1 to approach each other, and drives the two slide bars 43 to slide toward the middle in the slide groove 44, thereby reducing the spacing between the fixed balls w2, and inserting the top of the adjusting rod w3 into the crack, and then loosening the squeezing plate 3, and under the elastic force of the elastic mechanism 41, driving the slide bar 43 to slide outward, and then adjusting the upper ends of the rod w3 The two sides are close to the inner wall of the crack, and the straight-line distance between them is the crack width, which is set as D1;

[0048] Then, the sliding distance of the slide bar 43 is measured by the winding mechanism 42, and the slide bar 43 pulls the winding mechanism 42 when sliding, and under the elastic force of the coil spring t4, the scale bar t2 follows the movement of the slide bar 43 to stretch, so that when the scale bar t2 stretches, it squeezes and moves the friction ring t32, and drives the rotating ring t31 to rotate, and then the arc-shaped rotating ring t31 causes the scale bar t2 to slide in an arc, and the friction force of the scale bar t2 is increased by the friction ring t32, so as to avoid the scale bar t2 from sliding. When moving, it folds and blocks the size mark on the side. At the same time, the roller t3 limits the scale bar t2 to the outside of the installation groove 45. The dimension D2 on the scale bar t2 is observed through the observation window through the positioning port t5. In combination with the known length of the force arm w1 below the hinge axis w4 is L2, and the length of the force arm w1 above the hinge axis w4 and the entire length of the adjustment rod w3 is L1, the cosine theorem is used to deduce and convert D1=L1*D2 / L2, and then the width dimension of the crack is obtained.

[0049] In this embodiment, when the slide rod 43 slides inward on the slide groove 44, the sleeve a2 in the elastic mechanism 41 compresses the spring a4, causing the inner sleeve rod a1 to rotate around the hinge seat a3, and then maintains the elastic force outward under the elastic force of the spring a4, ensuring that after the extrusion plate 3 is released, the detection rod 1 at the upper end of the slide rod 43 is driven to expand the detection, maintain the elastic force on the slide rod 43, and then maintain the stability of the seam width detection through the elastic force.

[0050] Example 2

[0051] like Figure 6 , Figure 7 As shown, an underwater building crack detection device, the bottom end of the lever arm w1 extends to the inside of the installation groove 45 and is hinged with the slide bar 43, and the two sets of slide bars 43 slide and move inside the slide groove 44, thereby driving the two sets of lever arm w1 to move in a scissor-fork hinged manner;

[0052] The adjusting rod w3 includes a connecting rod w31, a clamping ring w32, a hollow rod w33, a supporting rod w34, and a limiting block w35. The connecting rod w31 is connected to the lever arm w1. The top of the connecting rod w31 is provided with a supporting rod w34. The outer side of the supporting rod w34 is sleeved with a clamping ring w32. The outer side of the clamping ring w32 is sleeved with a hollow rod w33. The hollow rod w33 is sleeved on the outer side of the supporting rod w34 as a whole. A limiting block w35 is jointly provided between the inner side of the hollow rod w33 and the clamping ring w32.

[0053] The upper and lower sides of the locking ring w32 are in a flat state, and are clearance-matched with the surface of the limit block w35. The locking ring w32 and the limit block w35 are made of magnets and have the characteristics of mutual adsorption. The side of the limit block w35 and the complete arc-shaped side of the locking ring w32 are adsorbed to each other, so that the hollow rod w33 is manually rotated to make the limit block w35 disengage from the blocking engagement of the side of the locking ring w32, and then pull the hollow rod w33 to make one side of the flat state of the locking ring w32 translate from the limit block w35 to the position of another hollow rod w33 for engagement and limiting, and then extend the adjusting rod w3. After the extension, the rotation of the hollow rod w33 is corrected, and the hollow rod w33 is prevented from rotating easily under the adsorption of the side of the limit block w35 and the side of the locking ring w32.

[0054] The use process of the underwater building crack detection device proposed in this embodiment is as follows: the length of the adjusting rod w3 is extended and adjusted, and when adjusting the length of the adjusting rod w3, the hollow rod w33 is manually rotated to make the limit block w35 disengage from the blocking engagement of the side of the clamping ring w32, and then the hollow rod w33 is pulled to make one side of the plane state of the clamping ring w32 translate from the limit block w35 to the position of another hollow rod w33 for clamping and limiting, and then the adjusting rod w3 is extended, and the rotation of the hollow rod w33 is returned to the normal position after the extension, and the limit block The adsorption of the side surface of w35 and the side surface of the locking ring w32 prevents the hollow rod w33 from rotating easily, and the adjusting rod w3 is extended to lengthen the distance between the fixed balls w2, and the lever arm w1 is cross-rotated with the hinge shaft w4 as a fulcrum. Under the elasticity of the lower end of the lever arm w1, the fixed balls w2 are supported between the cracks, and the distance of the lever arm w1 is observed to measure the crack width, so that the adjusting rod w3 can penetrate into the crack for detection, avoiding the resistance end of the adjusting rod w3 being too short and the detection depth being limited, and preventing the width of deeper cracks from not being measured.

[0055] The specific implementation methods of this embodiment are described above, but this embodiment is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Ordinary technicians in this field can also make many forms inspired by this embodiment, all of which are within the protection of this embodiment.

Claims

1. An underwater building crack detection device, comprising a detection rod (1), a hand-held groove (2), an extrusion plate (3), and a mounting box (4), characterized in that: The detection rod (1) is mounted on the top of the installation box (4), and the bottom end of the detection rod (1) extends to the inside of the installation box (4), the hand-held groove (2) is located on the left and right sides of the installation box (4), and two groups of extrusion plates (3) are symmetrically arranged on both sides of the top surface of the installation box (4), and one end of the two groups of extrusion plates (3) is respectively connected to the detection rod (1); The installation box (4) is provided with an elastic mechanism (41), a winding mechanism (42), a sliding rod (43), a sliding groove (44), and an installation groove (45) inside. The top of the installation box (4) is provided with an installation groove (45), and the front and rear ends of the inner wall of the installation groove (45) are symmetrically provided with slide grooves (44), and the same end of the two groups of slide grooves (44) are commonly provided with a slide rod (43), the bottom end of the elastic mechanism (41) is hinged to the bottom surface of the installation groove (45), and the top end of the elastic mechanism (41) is sleeved on the outside of the slide rod (43), and the winding mechanism (42) is installed in the middle of the top of the installation groove (45), and the output end of the winding mechanism (42) is connected to a group of slide rods (43); The winding mechanism (42) comprises a support ring (t1), a scale bar (t2), a winding roller (t3), and a winding spring (t4); the winding roller (t3) comprises a rotating ring (t31), a friction ring (t32), and a connecting rod (t33); the rotating ring (t31) is sleeved on the outside of the connecting rod (t33); the rotating ring (t31) is a cylindrical structure; the diameter of the middle part of the rotating ring (t31) is larger than the diameters of the two ends thereof; and the friction ring (t32) is fitted to the middle part of the outside of the rotating ring (t31); The bottom end of the detection rod (1) is sleeved on the outside of the sliding rod (43), and the displacement of the sliding rod (43) drives the detection rod (1) to follow the displacement.

2. The underwater building crack detection device according to claim 1, characterized in that: The bottom of the extrusion plate (3) is slidably connected to the top of the installation box (4), and a locking mechanism is provided between the top of the extrusion plate (3) and the installation box (4), so that the extrusion plate (3) is positioned on the top of the installation box (4), thereby positioning the detection rod (1).

3. The underwater building crack detection device according to claim 1, characterized in that: Support rings (t1) are fixedly installed in the middle of the front and rear ends of the inner wall of the installation groove (45), and the inner sides of the two groups of support rings (t1) are provided with coil springs (t4). The inner ends of the two groups of coil springs (t4) are commonly provided with winding rollers (t3), and the outer sides of the winding rollers (t3) are wound with a scale strip (t2), and the other end of the scale strip (t2) is fixedly connected to a group of sliding rods (43). The top ends of the outer sides of the support rings (t1) are provided with positioning openings (t5), and counting scales are provided on both sides of the scale strip (t2).

4. The underwater building crack detection device according to claim 3, characterized in that: Observation windows corresponding to the positioning opening (t5) are provided at both the front and rear ends of the installation box (4), and magnifying lenses are embedded in the interior of the observation windows.

5. The underwater building crack detection device according to claim 1, characterized in that: The elastic mechanism (41) comprises an inner sleeve rod (a1), a sleeve (a2), a hinge seat (a3), and a spring (a4); the hinge seat (a3) ​​is staggered and distributed at the bottom of the installation groove (45); the bottom end of the inner sleeve rod (a1) is hinged to the hinge seat (a3); the top end of the inner sleeve rod (a1) is sleeved with a sleeve (a2); the outer side of the sleeve (a2) and the outer side of the inner sleeve rod (a1) are sleeved with a positioning spring (a4); the top end of the sleeve (a2) is sleeved on the outer side of the slide rod (43).

6. The underwater building crack detection device according to claim 1, characterized in that: The detection rod (1) comprises a force arm rod (w1), a fixed ball (w2), an adjustment rod (w3), and a hinge shaft (w4); two groups of the force arm rods (w1) are cross-hinged in an "X" shape, and a hinge shaft (w4) is commonly provided at the hinge joint of the two groups of force arm rods (w1); an adjustment rod (w3) is provided at a position of the force arm rod (w1) close to the top of the hinge shaft (w4); and a fixed ball (w2) is provided at the top of the adjustment rod (w3).

7. The underwater building crack detection device according to claim 6, characterized in that: The bottom end of the lever arm (w1) extends to the inside of the installation slot (45) and is hinged to the slide rod (43). The two sets of slide rods (43) slide and move inside the slide slot (44), thereby driving the two sets of lever arm (w1) to move in a scissor-like hinged manner.

8. The underwater building crack detection device according to claim 7, characterized in that: The adjusting rod (w3) comprises a connecting rod (w31), a snap ring (w32), a hollow rod (w33), a support rod (w34), and a limit block (w35); the connecting rod (w31) is connected to the lever arm rod (w1); a support rod (w34) is arranged at the top end of the connecting rod (w31); a snap ring (w32) is sleeved on the outer side of the support rod (w34); a hollow rod (w33) is sleeved on the outer side of the snap ring (w32); the hollow rod (w33) is sleeved on the outer side of the support rod (w34) as a whole; and a limit block (w35) is arranged between the inner side of the hollow rod (w33) and the snap ring (w32).

9. The underwater building crack detection device according to claim 8, characterized in that: The length of the two groups of force arm rods (w1) below the hinge axis (w4) is L2, the sum of the length of the two groups of force arm rods (w1) above the hinge axis (w4) and the overall length of the adjustment rod (w3) is L1, the straight-line distance between the two groups of fixed balls (w2) is D1, and the straight-line distance between the bottom ends of the two groups of force arm rods (w1) is D2, then D1 / D2=L1 / L2.

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