CN113252258B

CN113252258B - Bridge crack detection device

Info

Publication number: CN113252258B
Application number: CN202110414865.2A
Authority: CN
Inventors: 卜凡民; 赵磊; 薛明钧; 薛艺
Original assignee: Cccc Fourth Highway Beijing Highway Test Checking Technology Co ltd
Current assignee: Cccc Fourth Highway Beijing Highway Test Checking Technology Co ltd
Priority date: 2021-04-17
Filing date: 2021-04-17
Publication date: 2022-09-06
Anticipated expiration: 2041-04-17
Also published as: CN113252258A

Abstract

The utility model relates to a bridge crack detection device belongs to the field that the bridge detected, be in including base and setting the pulley of base bottom surface is provided with the motor on the base, and the output of motor is fixed with the screw rod, the base top is provided with the elevating platform, and the elevating platform bottom surface is fixed with a lift section of thick bamboo, a lift section of thick bamboo and screw rod threaded connection, be fixed with on the base to overlap establish the lift section of thick bamboo outside and with a lift section of thick bamboo sliding connection's spacing section of thick bamboo, a lift section of thick bamboo can be followed a spacing section of thick bamboo and slided in vertical direction, is provided with the support on the elevating platform, and the joint has crack detection appearance in the support. This application has the effect that improves the convenience that detects bridge crack.

Description

Bridge crack detection device

Technical Field

The application relates to the field of bridge detection, in particular to a bridge crack detection device.

Background

Bridge is under the influence of driving for a long time and natural factor, and the bridge floor can produce the crack, and the crack is concentrated in the bridge bottom more, and at present in bridge detection, the staff can use bridge detection car to the bridge bottom, uses bridge crack detector to survey the crack.

The utility model discloses a there has been the china utility model patent of grant bulletin number CN207597217U at present to disclose a road crack detector, including the detector casing, the upper surface of detector casing is provided with electronic display screen, and one side of electronic display screen is provided with operating button, and the operating button bottom is pegged graft at the upper surface of detector casing, and one side of detector casing is provided with the data line slot, and data line slot inner wall is pegged graft and is had the data line plug, the end wall fixedly connected with data line of data line plug, the other end fixedly connected with detection head of data line.

Aiming at the related technologies, the inventor thinks that the staff needs to hold the crack detector on the bridge inspection vehicle to inspect the bottom of the bridge, and the labor intensity of the staff is high.

Disclosure of Invention

In order to improve the convenience to bridge crack detection, this application provides a bridge crack detection device.

The application provides a bridge crack detection device adopts following technical scheme:

the utility model provides a bridge crack detection device, is in including base and setting the pulley of base bottom surface is provided with the motor on the base, and the output of motor is fixed with the screw rod, the base top is provided with the elevating platform, and the elevating platform bottom surface is fixed with a lift section of thick bamboo, a lift section of thick bamboo and screw rod threaded connection, be fixed with on the base establish the cover establish the lift section of thick bamboo outside and with a lift section of thick bamboo sliding connection's spacing section of thick bamboo, a lift section of thick bamboo can be followed spacing section of thick bamboo and slided in vertical direction, is provided with the support on the elevating platform, and the joint has the crack detection appearance in the support.

Through adopting above-mentioned technical scheme, when detecting, the motor drive screw rod rotates, makes a lift section of thick bamboo slide along vertical direction in spacing section of thick bamboo, and the elevating platform is promoted and risees, makes crack detection appearance be close to the bridge bottom surface, then promotes bridge crack detection device, makes crack detection appearance detect each position of bridge bottom surface in proper order, improves and detects the convenience.

Optionally, be fixed with a plurality of support frame on the elevating platform, sliding connection has the slip ring on the support frame, and the support frame top is fixed with the stopper, and the cover is equipped with the promotion on the support frame the slip ring is close to the spring of stopper is fixed with the bracing piece on the slip ring, is provided with the support on the elevating platform, the tip of slip ring is kept away from at a plurality of bracing pieces to the leg joint.

Through adopting above-mentioned technical scheme, when promoting bridge crack detection appearance, if bridge crack detection device has rocks, the spring has the cushioning effect, makes the sliding ring slide slowly along the support frame, improves the stability of support, consequently improves crack detection appearance and detects accuracy nature.

Optionally, the limiting block is an elastic rubber block.

Through adopting above-mentioned technical scheme, when bridge crack detection device rocked, the slip ring probably touched the stopper when floating, and the stopper is elastic, consequently can reduce the reaction force that the slip ring produced when striking the stopper, improves the stability of support.

Optionally, the tip that the slip ring was kept away from to the bracing piece is fixed with curved butt shell, encloses into spherical cavity between a plurality of butt shell, and the support is including rotating the ball piece of connection in the cavity, and ball piece one end is fixed with the fixed disk that is used for installing the crack detector, and the ball piece other end is fixed with the weight, and weight and fixed disk are about ball piece central symmetry.

Through adopting above-mentioned technical scheme, when bridge crack detection device had the time of rocking, under the action of gravity of weight, can make the fixed disk face the bridge bottom surface all the time, the ball piece can be free rotation in the butt shell this moment, consequently reduces to rock the influence that detects to the crack detector, improves the stability that the crack detector detected.

Optionally, a magnet located right below the support is fixed on the lifting platform, the weight is a metal block, and a distance is reserved between the magnet and the weight.

Through adopting above-mentioned technical scheme, the magnet attracts the weight, and the weight receives towards the magnetic force effect of magnet, resumes steady in-process when bridge crack detection device by rocking, and the support may constantly rock because of inertia, until stopping, and under the action of gravity of magnetic force and weight, the stationary time that the fixed disk resumes shortens, improves the stability of support.

Optionally, be provided with the holding chamber with fixed disk top intercommunication in the fixed disk, be located the fixed disk border at holding chamber top and be fixed with elastic chucking board, chucking board extends to fixed disk central authorities, and the crack detector card inserts the holding intracavity.

Through adopting above-mentioned technical scheme, when installation crack detector, the chucking board can deform and make the crack detector fill in the holding intracavity, and the chucking board has the limiting displacement effect, reduces the crack detector possibility of following the roll-off in the fixed disk.

Optionally, a plurality of traction mechanisms are arranged between the base and the lifting platform, each traction mechanism comprises a spool arranged on the base, an elastic traction wire is wound on each spool, and the other end of each traction wire is connected to the lifting platform.

Through adopting above-mentioned technical scheme, after the elevating platform rises, the pull wire is pulled out from the spool to the pull wire is connected between base and elevating platform, further improves the stability that elevating platform and base are connected.

Optionally, the spool includes two supporting shoes of fixing on the base, rotates between two supporting shoes and is connected with the pivot, and the pull wire twines in the pivot, has still twined clockwork spring in the pivot, and clockwork spring one end is fixed in the pivot, and the other end is fixed on one of them supporting shoe.

Through adopting above-mentioned technical scheme, when the pull wire was drawn, the pivot rotated on the supporting shoe, and the pull wire can expand, and clockwork spring expandes simultaneously, and when the pull wire did not receive external force to draw, clockwork spring's elasticity made the pivot resume the normal position, and the pull wire is rolled up again in the pivot, makes pull wire automatic rolling, improves the convenience of use.

Optionally, the elevating platform top surface is fixed with a plurality of hydraulic support component, hydraulic support component is including fixing two regulation section of thick bamboo at the elevating platform top surface, the intercommunication groove that the notch width is greater than the tank bottom width in the regulation section of thick bamboo, be fixed with communicating pipe between two regulation section of thick bamboo, communicating pipe all communicates with two intercommunication inslot portions, sliding connection has the piston in the regulation section of thick bamboo, the piston is deformable and supports tightly and adjusts a section of thick bamboo inner wall, one of them piston is connected with the pull wire, another piston connection has and promotes the piece, it connects on the support frame to promote piece sliding connection, the spring bottom mounting is on promoting the piece.

By adopting the technical scheme, when the lifting platform is lifted, the traction line applies downward force to one piston, liquid enters the other adjusting cylinder through the communicating pipe, the other piston slides upwards, the pushing block is pushed, the pushing block slides upwards along the supporting frame, the spring is pushed, the spring is tightly abutted to the sliding ring, and therefore the stability of the support connected with the sliding ring is further improved.

In summary, the present application includes at least one of the following beneficial technical effects:

1. when in detection, the lifting cylinder slides in the limiting cylinder along the vertical direction, the lifting platform is pushed to rise, the crack detector is enabled to be close to the bottom surface of the bridge, then the bridge crack detection device is pushed, the crack detector is enabled to detect each position of the bottom surface of the bridge in sequence, and the detection convenience is improved;

2. when the bridge crack detection device is restored to be stable from shaking, the time for the fixed disc to restore to be stable is shortened under the action of magnetic force and the gravity of the heavy hammer, and the stability of the support is improved;

3. when the lifting platform is lifted, the traction wire is pulled out from the wire shaft and is connected between the base and the lifting platform, so that the connection stability of the lifting platform and the base is further improved;

4. the traction line applies downward force to one piston, liquid enters the other adjusting cylinder through the communicating pipe, the other piston slides upwards, the pushing block is pushed, the pushing block slides upwards along the supporting frame, the spring is pushed, and the spring is tightly abutted to the sliding ring, so that the stability of the support connected with the sliding ring is further improved.

Drawings

FIG. 1 is a schematic diagram of the overall structure of the present application;

FIG. 2 is a schematic cross-sectional structure of the present application;

FIG. 3 is an enlarged schematic view of portion A of FIG. 2;

FIG. 4 is a schematic structural view of a sliding connection between a lifting cylinder and a limiting cylinder according to the present application;

FIG. 5 is a schematic structural view of a stent of the present application;

FIG. 6 is a schematic view of the traction mechanism of the present application;

fig. 7 is a schematic view of the structure of a power spring in the present application.

Description of reference numerals: 1. a base; 11. a pulley; 2. a lifting mechanism; 21. a motor; 22. a screw; 23. a lifting cylinder; 231. a slide bar; 24. a limiting cylinder; 241. a chute; 3. a lifting platform; 4. a crack detector; 5. a support frame; 51. a limiting block; 52. a spring; 6. a slip ring; 7. a pushing block; 8. a support bar; 9. abutting the housing; 10. a cavity; 12. a support; 121. a ball block; 122. fixing the disc; 1221. an accommodating cavity; 1222. a chucking plate; 123. a weight; 13. a magnet; 14. a traction mechanism; 141. a bobbin; 1411. a support block; 1412. a rotating shaft; 1413. a partition plate; 1414. a clockwork spring; 142. a pull wire; 15. a chamber; 16. a hydraulic support assembly; 161. an adjusting cylinder; 1611. a communicating groove; 162. a piston; 1621. a plug body; 1622. a connecting rod; 163. a communication pipe is provided.

Detailed Description

The present application is described in further detail below with reference to figures 1-7.

The embodiment of the application discloses bridge crack detection device. Referring to fig. 1, the bridge crack detection device comprises a base 1 and a lifting mechanism 2 arranged on the base 1, wherein a lifting platform 3 is fixed on the lifting mechanism 2, and a crack detector 4 is arranged on the lifting platform 3. When detection is carried out, the lifting mechanism 2 drives the lifting platform 3 to lift upwards, so that the crack detector 4 is close to the bottom surface of the bridge.

Referring to fig. 2 and 3, pulleys 11 are installed at four corners of the bottom surface of the base 1, so that a worker can conveniently move the position of the bridge crack detection device. The lifting mechanism 2 comprises a motor 21 fixed in the base 1, and the output end of the motor 21 faces upwards. A screw rod 22 is also arranged above the base 1, and the bottom end of the screw rod 22 is fixed at the output end of the motor 21. A cylindrical elevating cylinder 23 is externally sleeved on the screw 22, the elevating cylinder 23 is in threaded connection with the screw 22, and the top end of the elevating cylinder 23 is fixed on the bottom surface of the elevating table 3.

Referring to fig. 2 and 4, a cylindrical limiting cylinder 24 is further sleeved outside the lifting cylinder 23, the bottom end of the limiting cylinder 24 is fixed on the base 1, a sliding groove 241 is formed in the inner wall of the limiting cylinder 24, the extending direction of the sliding groove 241 is parallel to the axial direction of the screw 22, a sliding strip 231 is fixed on the outer wall of the lifting cylinder 23, and the sliding strip 231 is inserted into the sliding groove 241 and can slide along the sliding groove 241. Under the limit of the limit cylinder 24, the lifting cylinder 23 can only slide along the vertical direction, the motor 21 drives the screw 22 to rotate when rotating, and the lifting cylinder 23 lifts to drive the lifting platform 3 to lift.

Referring to fig. 1 and 2, at least one pair of support rods 8 are fixed on the upper surface of the lifting table 3, a limit block 51 with a radius larger than that of the support frame 5 is fixed at the top end of the support frame 5, and the limit block 51 is made of rubber. A sliding ring 6 and a pushing block 7 are connected on the supporting frame 5 in a sliding way. A spring 52 is sleeved on the support frame 5, one end of the spring 52 is fixed on the sliding ring 6, and the other end is fixed on the pushing block 7. When the spring 52 is in the original length state, the sliding ring 6 is pushed by the spring 52 to abut against the limiting block 51, and when the lifting platform 3 shakes, the spring 52 can buffer the impact force, reduce the shaking force transmitted to the sliding ring 6, and reduce the sliding amplitude of the sliding ring 6; and after the slip ring 6 collides with the stopper 51, the stopper 51 is deformable to buffer the impact on the slip ring 6.

A support rod 8 which horizontally extends out is fixed on the side wall of the sliding ring 6, and an arc-shaped abutting shell 9 is fixed at the end part of the support rod 8 which is far away from the sliding ring 6. The plurality of abutting shells 9 are arranged to face each other, and a spherical cavity 10 is formed in the center of the plurality of abutting shells 9, and a holder 12 for mounting a probe is provided in the cavity 10.

Referring to fig. 2 and 5, the bracket 12 includes a ball block 121 rotatably connected in the abutting housing 9, a fixing rod is fixed on a side wall of the ball block 121, a fixing plate 122 is fixed at an end of the fixing rod, a containing cavity 1221 is provided in the fixing plate 122, a clamping plate 1222 extending toward the center is provided at an upper port of the fixing plate 122, and the clamping plate 1222 is made of rubber. After the probe is plugged into the accommodating cavity 1221, the clamping plate 1222 can be tightly attached to the probe, and the probe is limited in the fixing plate 122. A weight 123 is fixed on the other side of the ball 121, the weight 123 and the fixing plate 122 are symmetrical about the center of the ball 121, and the fixing plate 122 is suspended above the ball 121 under the gravity of the weight 123.

When the bridge crack detection device is pushed, if the lifting platform 3 shakes, the spring 52 can buffer the impact, so that the shaking force transmitted to the sliding ring 6 is reduced, and the stability of the support 12 is improved. And when the elevating platform 3 inclines due to shaking, under the action of the gravity of the heavy hammer 123, the ball block 121 rotates in the abutting shell 9, the fixed disk 122 always faces the bottom surface of the bridge, so that the picture shot by the detecting head is stable, and the detection accuracy can be improved.

In order to further improve the stability of the stand 12, a magnet 13 is fixed to the upper surface of the elevating platform 3, and the magnet 13 is located directly below the weight 123 and spaced apart from the weight 123. Since the weight 123 is made of metal, the weight 123 receives a magnetic force toward the magnet 13. The magnetic force is smaller than the gravity of the weight 123, and when the lifting platform 3 shakes, the front surface of the fixed disc 122 still faces the bottom surface of the bridge; however, if the support 12 still shakes during the process of restoring the lifting platform 3 to the original position, the gravity of the weight 123 and the magnetic force applied thereto are both vertically downward, so that the shaking of the support 12 caused by inertia is reduced, and the time for restoring the support 12 to the original position is shortened.

Referring to fig. 1 and 2, when the elevating platform 3 is elevated to a high level, the length of the connection between the elevating cylinder 23 and the screw 22 is short, the elevating platform 3 may be unstable, and in order to enhance the stability of the elevating platform 3 after elevation, a plurality of traction mechanisms 14 are connected between the base 1 and the elevating platform 3, and the number of the traction mechanisms 14 is the same as that of the supporting frames 5.

The base 1 is provided with a cavity 15, the traction mechanism 14 comprises a spool 141 arranged in the cavity 15, a traction wire 142 is wound on the spool 141, the traction wire 142 is a cord with elasticity, and the traction wire 142 extends out of the cavity 15. A wire hole is formed in the lifting platform 3, the traction wire 142 is pulled to the lifting platform 3 from the base 1, penetrates through the wire hole and is pulled out of the upper surface of the lifting platform 3, a hydraulic support component 16 is arranged on the upper surface of the lifting platform 3, and the hydraulic support component 16 is connected with the traction wire 142 and the pushing block 7 respectively.

Referring to fig. 2 and 6, the spool 141 includes support blocks 1411 fixed in the chamber 15, a rotation shaft 1412 is rotatably connected between the support blocks 1411, and the traction wire 142 is wound around the rotation shaft 1412. When the pulling wire 142 is pulled by an external force, the rotating shaft 1412 can rotate, so that the pulling wire 142 is smoothly pulled out.

Referring to fig. 6 and 7, a partition 1413 is further fixed on the rotating shaft 1412, the traction wire 142 is wound on the rotating shaft 1412 between the partition 1413 and one of the supporting blocks 1411, a clockwork spring 1414 is wound on the rotating shaft 1412 on the other side of the partition 1413, one end of the clockwork spring 1414 is fixed on the rotating shaft 1412, and the other end is fixed on the adjacent supporting block 1411. Therefore, when the pulling wire 142 is not pulled by external force, the elastic force of the clockwork spring 1414 pulls the rotating shaft 1412 to return to the original position, the pulling wire 142 is rewound on the rotating shaft 1412, and the pulling wire 142 is automatically wound.

Referring to fig. 2 and 3, the hydraulic support assembly 16 includes two adjusting cylinders 161 fixed on the upper surface of the lifting table 3, a communicating groove 1611 is provided in the two adjusting cylinders 161, the top end of the adjusting cylinder 161 is open, the width of the opening of the adjusting cylinder 161 is smaller than the inner width of the cylinder, and each adjusting cylinder 161 is provided with a piston 162. The piston 162 includes a plug 1621 of rubber material abutting against the inner wall of the adjusting cylinder 161, a connecting rod 1622 is fixed on the plug 1621, and the connecting rod 1622 can extend out from the top end of the adjusting cylinder 161. A communicating pipe 163 is fixed between the two adjusting cylinders 161, and the communicating pipe 163 is communicated with the inside of the first adjusting cylinder 161 and the second adjusting cylinder 161. The communicating groove 1611 is filled with liquid, and the liquid can freely flow between the two adjusting cylinders 161 through the communicating pipe 163.

The pull wire 142 is fixed on the top end of one of the connecting rods 1622, and the pushing block 7 is fixed on the top end of the connecting rod 1622 close to the support frame 5. When the lifting platform 3 is lifted, the pulling wire 142 is stretched, and at the same time, because the pulling wire 142 has elasticity, the connecting rod 1622 is subjected to the downward acting force exerted by the pulling wire 142, so that the plug body 1621 connected with the connecting rod slides towards the bottom of the communication groove 1611, and the liquid is extruded into the other adjusting cylinder 161 through the communication pipe 163. The other piston 162 is pushed and slides upwards along the adjusting cylinder 161, the connecting rod 1622 pushes the pushing block 7, the pushing block 7 slides upwards along the supporting frame 5, so the spring 52 is squeezed, the spring 52 pushes the sliding ring 6 to abut against the limiting block 51, and the sliding amplitude of the sliding ring 6 along the supporting frame 5 is reduced. Therefore, in the lifting process of the lifting platform 3, the traction wire 142 can stabilize the lifting platform 3 and simultaneously stabilize the support 12, so that the shaking generated by the support 12 is reduced.

When the measurement is completed, the elevating platform 3 is driven to descend, and the traction wire 142 is wound. The weight of the bracket 12, the probe and the sliding ring 6 pushes the sliding ring 6 to slide down along the supporting frame 5, the spring 52 is compressed and pushes the pushing block 7, and the pushing block 7 presses the second connecting rod 1622 to lower the second piston 162. When the bridge crack detecting apparatus is used again, the second piston 162 may be pushed again.

The implementation principle of the bridge crack detection device in the embodiment of the application is as follows: when the bridge crack detection device is used for detecting the bottom surface of a bridge, a detection head is firstly plugged into the accommodating cavity 1221, and the clamping plate 1222 is abutted against the detection head.

Then the driving motor 21 rotates, the screw 22 is driven to rotate, the lifting cylinder 23 slides upwards along the sliding groove 241 under the limit of the limit cylinder 24, and the lifting platform 3 is pushed to slide upwards, so that the probe is close to the bottom surface of the bridge.

During the ascending process of the lifting platform 3, the pulling wire 142 is pulled out, and the pulling wire 142 pulls one of the connecting rods 1622 to slide downwards, so that the piston 162 connected with the pulling wire slides towards the inside of the adjusting cylinder 161, the liquid pushes the other piston 162 to slide upwards along the other adjusting cylinder 161, the pushing block 7 slides upwards along the supporting frame 5, and the spring 52 pushes the sliding ring 6 to abut against the limiting block 51.

The staff promotes bridge crack detection device, makes the detecting head shoot the bridge bottom surface in proper order. When the bridge crack detection device is pushed, if the lifting platform 3 tilts due to shaking, the ball block 121 rotates in the cavity 10 under the action of the gravity of the heavy hammer 123, so that the fixed disc 122 always faces the bottom surface of the bridge; when the bridge crack detection device is restored to balance by shaking, the magnetic force of the magnet 13 and the gravity of the weight 123 make the support 12 keep stable, and the shaking of the support 12 caused by inertia is reduced.

When the detection is completed, the driving motor 21 rotates, the screw 22 drives the lifting cylinder 23 to slide downwards, and the lifting platform 3 descends. After the pulling wire 142 is pulled by no external force, the elastic force of the spring 141 pulls the rotating shaft 1412 to rotate back, and the excess pulling wire 142 is wound on the spool 141.

The above embodiments are preferred embodiments of the present application, and the protection scope of the present application is not limited by the above embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims

1. The utility model provides a bridge crack detection device which characterized in that: comprises a base (1) and pulleys (11) arranged on the bottom surface of the base (1), wherein a motor (21) is arranged on the base (1), a screw rod (22) is fixed at the output end of the motor (21), a lifting platform (3) is arranged above the base (1), a lifting cylinder (23) is fixed on the bottom surface of the lifting platform (3), the lifting cylinder (23) is in threaded connection with the screw rod (22), a limiting cylinder (24) which is sleeved outside the lifting cylinder (23) and is in sliding connection with the lifting cylinder (23) is fixed on the base (1), the lifting cylinder (23) can slide in the vertical direction along the limiting cylinder (24), a support (12) is arranged on the lifting platform (3), a crack detector (4) is clamped in the support (12), a plurality of support frames (5) are fixed on the lifting platform (3), a sliding ring (6) is connected on the support frames (5), a limiting block (51) is fixed on the top ends of the support frames (5), a spring (52) for pushing the sliding ring (6) to be close to the limiting block (51) is sleeved on the supporting frame (5), a supporting rod (8) is fixed on the sliding ring (6), a bracket (12) is arranged on the lifting platform (3), the bracket (12) is connected with the end parts of the plurality of support rods (8) far away from the sliding ring (6), stopper (51) is for having elastic block rubber, the tip that sliding ring (6) was kept away from in bracing piece (8) is fixed with curved butt shell (9), enclose into spherical cavity (10) between a plurality of butt shell (9), support (12) are including rotating ball piece (121) of connecting in cavity (10), ball piece (121) one end is fixed with fixed disk (122) that are used for installing crack detector (4), ball piece (121) other end is fixed with weight (123), weight (123) and fixed disk (122) are about ball piece (121) central symmetry.

2. The bridge crack detection device of claim 1, wherein: a magnet (13) positioned right below the support (12) is fixed on the lifting platform (3), the heavy hammer (123) is a metal material block, and a distance is reserved between the magnet (13) and the heavy hammer (123).

3. The bridge crack detection device of claim 1, wherein: an accommodating cavity (1221) communicated with the top of the fixed disk (122) is formed in the fixed disk (122), an elastic clamping plate (1222) is fixed on the edge of the fixed disk (122) positioned at the top of the accommodating cavity (1221), the clamping plate (1222) extends towards the center of the fixed disk (122), and the crack detector (4) is clamped into the accommodating cavity (1221).

4. The bridge crack detection device of claim 1, wherein: a plurality of traction mechanisms (14) are arranged between the base (1) and the lifting platform (3), each traction mechanism (14) comprises a bobbin (141) arranged on the base (1), an elastic traction wire (142) is wound on each bobbin (141), and the other end of each traction wire (142) is connected to the lifting platform (3).

5. The bridge crack detection device of claim 4, wherein: the spool (141) comprises two supporting blocks (1411) fixed on a base (1), a rotating shaft (1412) is rotatably connected between the two supporting blocks (1411), a traction wire (142) is wound on the rotating shaft (1412), a clockwork spring (1414) is further wound on the rotating shaft (1412), one end of the clockwork spring (1414) is fixed on the rotating shaft (1412), and the other end of the clockwork spring (1414) is fixed on one of the supporting blocks (1411).

6. The bridge crack detection device of claim 5, wherein: the hydraulic support assembly comprises two adjusting cylinders (161) fixed on the top surface of the lifting platform (3), a communicating groove (1611) with the groove opening width larger than the groove bottom width is formed in each adjusting cylinder (161), a communicating pipe (163) is fixed between the two adjusting cylinders (161), each communicating pipe (163) is communicated with the inside of each communicating groove (1611), a piston (162) is connected in each adjusting cylinder (161) in a sliding mode, each piston (162) can deform and tightly abut against the inner wall of each adjusting cylinder (161), one piston (162) is connected with a pull wire (142), the other piston (162) is connected with a pushing block (7), each pushing block (7) is connected to a support frame (5) in a sliding mode, and the bottom end of each spring (52) is fixed to the corresponding pushing block (7).