Testing device and testing method for self-weight stress of crane main beam

Abstract

The invention belongs to the technical field of crane main beam testing, and particularly relates to a crane main beam self-weight stress testing device and method. The crane main beam self-weight stress testing device comprises a supporting frame composed of two supporting arms perpendicular to each other; a group of permanent magnets are arranged on the bottom surface of the support frame, and a pair of symmetrical laser transmitters are mounted on the support frame; the knob is movably connected with the central part of the support frame; the self-weight stress testing device is installed on a lower cover plate of a main beam of the crane and located at the position close to the midspan of the main beam, in order to conveniently adjust the installation direction of the self-weight stress testing device, a laser transmitter is turned on, laser rays are parallel to the x-axis direction of the main beam, and the self-weight stress testing device is fixed to the lower cover plate of the main beam through a permanent magnet. The two ultrasonic surface wave sensors are used for measuring the y axis and the x axis of the main beam, excitation and receiving information records are improved, and finally the self-weight stress value of the main beam of the crane is obtained according to information obtained through calculation of the testing method.

Description

Technical Field

[0001] The invention belongs to the technical field of crane main beam testing, in particular to a testing device and a testing method for the deadweight stress of a crane main beam. Background Art

[0002] Cranes are widely used in material handling places such as ports, factories and mines. However, long-term high-load operation will reduce the load-bearing capacity of cranes. When cranes reach a certain service life, there is a general need for safety assessment. In recent years, my country has successively issued a series of standards, including "Safety Assessment Procedure for Tower Cranes" (GB / T 33080-2016), "Safety Status Assessment of Lifting Machinery" (T / CASEI 62001-2019), and "General Requirements for Safety Assessment of Lifting Machinery" (GB / T 41510-2022). Among them, all of them put forward the requirement of stress testing of cranes. Therefore, stress testing is an important means of crane safety assessment. However, the above technologies often have the following defects: in the stress test of the crane, only the stress increment of the crane in the loaded state and the unloaded state can be measured, and the deadweight stress of the crane cannot be obtained. Since the deadweight of the crane is very large, the impact on the stress test results cannot be ignored. At present, the deadweight stress of the main beam of the bridge (gantry) crane is mainly roughly estimated by the size of the main beam. However, the deadweight stress estimated by this method has a large error, which greatly affects the safety assessment results of the crane. The residual stress tester can also measure the tensile state of metal materials. However, most residual stress detectors are large in size and cannot measure the deadweight stress of the crane main beam in the air. The detection device of the ultrasonic surface wave residual stress detection technology is small in size and portable, and is suitable for residual stress detection of plates. However, the ultrasonic surface wave residual stress detection technology needs to calibrate the speed of the ultrasonic surface wave at zero stress in the material to be detected at the experimental temperature before detection. The calibration process requires the material to be known, which is generally completed on a tensile machine. However, most cranes that undergo stress testing are old cranes, which usually have missing design data, unknown materials, and cannot be calibrated in the laboratory. Therefore, the present invention provides a testing device and a testing method for the deadweight stress of a crane main beam. Summary of the invention

[0003] In order to make up for the deficiencies of the prior art, at least one technical problem raised in the background technology is solved.

[0004] The technical solution adopted by the present invention to solve the technical problem is as follows: a test device for the deadweight stress of a crane main beam of the present invention comprises a support frame composed of two mutually perpendicular support arms; a group of permanent magnets are arranged on the bottom surface of the support frame, and a pair of symmetrical laser transmitters are installed on the support frame; The knob is movably connected to the central part of the support frame, the knob is fixedly connected to a support beam, and the bottom surface of the support beam is fixedly connected to a pair of ultrasonic surface wave sensors.

[0005] Preferably, a hollow arc-shaped plate is fixedly connected to the bottom surface of the support frame, a slide groove is provided on the bottom surface of the arc-shaped plate, a connecting rod is slidably connected to the inner wall of the slide groove, and the connecting rod is arranged on the permanent magnet.

[0006] Preferably, the top surface of the connecting rod is sealingly and slidingly connected to a hollow connecting column, the top surface of the connecting column is fixedly connected to a suction cup, a connecting groove is provided in the permanent magnet, the connecting rod is sealingly and slidingly connected to the top surface of the permanent magnet and extends into the connecting groove, the interior of the connecting rod is a hollow structure, and the top end of the connecting rod is opened, and the bottom end of the connecting rod is provided with an air inlet hole.

[0007] Preferably, one end of the suction cup close to the connecting column is connected to a hollow conduit, a piston is sealingly and slidingly connected inside the conduit, a limiting ring located above the piston is fixedly connected to the inner wall of the conduit, and a driving component for driving the piston to move is arranged inside the conduit.

[0008] Preferably, the driving assembly includes a first rack and a second rack, the first rack is slidably connected to the bottom surface of the connecting rod, the side wall of the first rack is fixedly connected to a first spring through a bracket, the bottom end of the first spring is fixedly connected to the inner wall of the connecting rod, the top surface of the second rack is fixedly connected to the piston, and a gear is meshed between the first rack and the second rack.

[0009] Preferably, an annular movable groove is provided on the bottom surface of the permanent magnet, a hollow ring is sealed and slidably connected in the movable groove, the top of the hollow ring is opened, and a group of exhaust holes are provided on the inner wall of the hollow ring, the inner wall of the movable groove is fixedly connected to a second spring through a bracket, the bottom end of the second spring is fixedly connected to the hollow ring, a hollow groove is provided in the permanent magnet, an air intake groove connected to the movable groove is provided on the inner wall of the hollow groove, and an air intake mechanism is provided in the hollow groove.

[0010] Preferably, the air intake mechanism includes a push plate that slides in a sealing manner with the inner wall of the hollow groove, a third spring is fixedly connected between the top surface of the push plate and the inner wall of the hollow groove, a slide rod is slidably connected to the bottom surface of the permanent magnet, and the top end of the slide rod is fixedly connected to the push plate.

[0011] Preferably, the exhaust hole is arranged to be inclined downward, and the inner wall of the hollow ring is twisted with a sealing plate for sealing the exhaust hole through a torsion spring.

[0012] A method for testing the self-weight stress of a crane main beam, the method adopts the above-mentioned device for testing the self-weight stress of a crane main beam, and the method comprises the following steps: S1: Install the self-weight stress test device on the lower cover plate of the crane main beam, near the middle of the main beam span, turn on the laser transmitter, and make the laser line parallel to the x-axis direction of the main beam. At this time, use a permanent magnet to fix the self-weight stress test device on the lower cover plate of the main beam; S2: Adjust the support beam so that it is along the y-axis direction of the main beam, and adjust the knob so that the support beam drives the ultrasonic surface wave sensor to fit on the lower cover plate of the crane main beam; S3: Complete the excitation and reception of an ultrasonic surface wave between the two ultrasonic surface wave sensors, record the propagation time t0 of the ultrasonic surface wave, the distance between the two ultrasonic surface wave sensors is s, and calculate the propagation speed of the ultrasonic surface wave v0=s / t0. Since the length of the main beam is much larger than the width of the main beam, the self-weight stress along the y-axis direction can be ignored. Therefore, the speed v0 at this time is taken as the propagation speed of the ultrasonic surface wave at zero stress. S4: Adjust the knob to make the bracket crossbeam drive the ultrasonic surface wave sensor away from the lower cover plate of the main beam, adjust the bracket crossbeam to make the bracket crossbeam along the x-axis direction of the main beam, and adjust the knob to make the bracket crossbeam drive the ultrasonic surface wave sensor to fit on the lower cover plate of the crane main beam; S5: complete the excitation and reception of an ultrasonic surface wave between the two ultrasonic surface wave sensors, record the propagation time t1 of the ultrasonic surface wave, the distance between the two ultrasonic surface wave sensors is s, and calculate the propagation speed v1=s / t1 of the ultrasonic surface wave; S6: Perform stress testing on the crane, load the crane, and use a stress tester to measure the stress of the crane main beam under load. At the same time, complete the excitation and reception of ultrasonic surface waves between two ultrasonic surface wave sensors, record the propagation time t2 of the ultrasonic surface wave, and calculate the propagation speed v2=s / t2 of the ultrasonic surface wave; S7: The deadweight stress of the crane main beam can be calculated based on the obtained excitation and received recorded data.

[0013] The beneficial effects of the present invention are as follows: 1. The present invention installs the self-weight stress testing device on the lower cover plate of the crane main beam, which is located near the middle of the main beam span. In order to facilitate the adjustment of the installation direction of the self-weight stress testing device, the laser transmitter is turned on to make the laser line parallel to the x-axis direction of the main beam. The self-weight stress testing device is fixed to the lower cover plate of the main beam using a permanent magnet, so that two ultrasonic surface wave sensors measure the y-axis and x-axis of the main beam, thereby improving the recording of excitation and reception information. Finally, the self-weight stress value of the crane main beam is obtained by calculating the information obtained through the test method.

[0014] 2. In the present invention, after the support frame is fixed on the lower cover plate of the main beam by permanent magnets, when the position of the support frame needs to be adjusted, it is only necessary to rotate the support frame to allow the connecting rod to slide in the slide groove. At this time, the support frame will rotate in a circle, thereby adjusting the position of the support frame to be parallel to the x-axis direction of the main beam, thereby improving the convenience of using the self-weight stress testing device.

[0015] The invention is suitable for testing the deadweight stress of the main beam of a bridge crane or a gantry crane. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be further described below in conjunction with the accompanying drawings.

[0017] Figure 1 is a three-dimensional diagram of the test device of the present invention; Figure 2 It is a schematic diagram of the structure of the arc plate and the permanent magnet in the present invention; Figure 3 It is a schematic diagram of the internal structure of the arc plate and the permanent magnet in the present invention; Figure 4 yes Figure 3 Schematic diagram of the local structure; Figure 5 It is a schematic diagram of the partial internal structure of the permanent magnet in the present invention; Figure 6 is a top view of the hollow ring of the present invention; Figure 7 It is a flow chart of the method in the present invention.

[0018] In the figure: 1, support frame; 2, permanent magnet; 3, support beam; 4, ultrasonic surface wave sensor; 5, knob; 6, laser transmitter; 7, arc plate; 8, slide groove; 9, connecting rod; 10, connecting groove; 11, connecting column; 12, suction cup; 13, first rack; 14, second rack; 15, piston; 16, limit ring; 17, movable groove; 18, hollow ring; 19, exhaust hole; 20, slide rod; 21, push plate; 22, hollow groove; 23, air inlet groove; 24, conduit; 25, sealing plate. DETAILED DESCRIPTION

[0019] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0020] Embodiment 1: Figures 1 to 5 As shown, a crane main beam self-weight stress testing device according to an embodiment of the present invention comprises a support frame 1 composed of two mutually perpendicular support arms; a group of permanent magnets 2 are arranged on the bottom surface of the support frame 1, and a pair of symmetrical laser emitters 6 are installed on the support frame 1; A knob 5, wherein the knob 5 is movably connected to the central part of the support frame 1, a support beam 3 is fixedly connected to the knob 5, and a pair of ultrasonic surface wave sensors 4 are fixedly connected to the bottom surface of the support beam 3; The ultrasonic surface wave sensor 4 has one sensor excitation signal and the other sensor receiving signal. The main beam only needs to estimate the self-weight stress during the stress test. Therefore, the self-weight stress estimation of this patent is carried out simultaneously with the stress test of the main beam. The estimation of self-weight stress is based on the acoustic elasticity of ultrasonic surface waves. Acoustic elasticity is related to material and temperature. Since the ambient temperature remains basically unchanged during the test, the influence of ambient temperature on the propagation speed of ultrasonic surface waves can be ignored. The self-weight stress test device is installed on the lower cover plate of the crane main beam, near the mid-span of the main beam. In order to facilitate the adjustment of the installation direction of the self-weight stress test device, turn on the laser transmitter 6 to make the laser line parallel to the x-axis direction of the main beam. At this time, use the permanent magnet 2 to fix the self-weight stress test device to the lower cover plate of the main beam (the material of the crane main beam is usually ferromagnetic material), adjust the bracket beam 3 to make the bracket beam 3 along the y-axis direction of the main beam, adjust the knob 5, make the bracket beam 3 drive the ultrasonic surface wave sensor 4 to fit on the lower cover plate of the crane main beam, so that the ultrasonic surface wave is excited and received once between the two ultrasonic surface wave sensors 4, and the excitation and reception information is recorded. Since the length of the main beam is much larger than the width of the main beam, the self-weight stress along the y-axis direction can be ignored, and adjust the knob 5 to make the bracket beam 3 drive the ultrasonic surface wave sensor 4 away from the lower cover plate of the crane main beam, so that the bracket beam 3 can rotate freely. The support crossbeam 3 is adjusted so that the support crossbeam 3 is along the x-axis direction of the main beam, and the knob 5 is adjusted so that the support crossbeam 3 drives the ultrasonic surface wave sensor 4 to fit on the lower cover plate of the crane main beam, so that the two ultrasonic surface wave sensors 4 complete the excitation and reception of ultrasonic surface waves, record the excitation and reception information, and perform the stress test of the crane. The crane is loaded, and a stress tester (such as a resistance strain stress tester or a fiber grating stress tester) is used to measure the stress of the crane main beam under the load state. At the same time, the two ultrasonic surface wave sensors 4 complete the excitation and reception of ultrasonic surface waves, record the excitation and reception information, and finally calculate the self-weight stress value of the crane main beam through the information obtained by the test method. This patent can complete the calibration of the acoustic elastic constant k1 and the test of the self-weight stress of the crane main beam under the premise that the main beam material parameters and temperature are unknown.

[0021] The bottom surface of the support frame 1 is fixedly connected with a hollow arc plate 7, and a slide groove 8 is provided on the bottom surface of the arc plate 7. The inner wall of the slide groove 8 is slidably connected with a connecting rod 9, and the connecting rod 9 is arranged on the permanent magnet 2; in order to facilitate the adjustment of the installation direction of the self-weight stress test device, the laser line needs to be parallel to the x-axis direction of the main beam, but manual operation is prone to errors, resulting in the laser line not being parallel to the x-axis direction of the main beam, which means that the support frame 1 is not parallel to the x-axis direction of the main beam. Since the support frame 1 is adsorbed on the lower cover plate of the main beam through the permanent magnet 2, the position of the support frame 1 is not easy to adjust at this time, which affects the subsequent deviation in the adjustment of the installation direction of the self-weight stress test device. In this application, after the support frame 1 is fixed on the lower cover plate of the main beam through the permanent magnet 2 through the above-mentioned mechanism, when the position of the support frame 1 needs to be adjusted, it is only necessary to rotate the support frame 1 to let the connecting rod 9 slide in the slide groove 8. At this time, the support frame 1 will rotate in a circle, thereby adjusting the position of the support frame 1 to be parallel to the x-axis direction of the main beam, thereby improving the convenience of using the self-weight stress test device.

[0022] The top surface of the connecting rod 9 is sealed and slidably connected with a hollow connecting column 11, and the top surface of the connecting column 11 is fixedly connected with a suction cup 12. A connecting groove 10 is provided in the permanent magnet 2, and the connecting rod 9 is sealed and slidably connected to the top surface of the permanent magnet 2 and extends into the connecting groove 10. The interior of the connecting rod 9 is a hollow structure, and the top end of the connecting rod 9 is opened, and the bottom end of the connecting rod 9 is provided with an air inlet hole. After the support frame 1 is adjusted to a suitable position, the support frame 1 can be pressed to make the arc plate 7 push the connecting rod 9. At this time, the connecting rod 9 will move in the connecting groove 10. At this time, the gas in the connecting groove 10 will enter the connecting rod 9 from the air inlet hole and push the connecting column 11, so that the connecting column 11 pushes the suction cup 12 to be adsorbed on the arc plate 7. At this time, the connecting rod 9 is fixed on the arc plate 7, so that the support frame 1 is fixed, thereby achieving the effect of fixing the adjusted support frame 1.

[0023] The end of the suction cup 12 close to the connecting column 11 is connected to a hollow conduit 24, and a piston 15 is sealingly and slidably connected inside the conduit 24. The inner wall of the conduit 24 is fixedly connected to a limit ring 16 located above the piston 15, and a driving component for driving the piston 15 to move is arranged in the conduit 24; after the suction cup 12 is adsorbed on the inner wall of the arc plate 7, the driving component can be used to drive the piston 15 to slide toward the side close to the permanent magnet 2. At this time, the piston 15 will suck the gas in the suction cup 12, so that the piston 15 is more firmly adsorbed on the inner wall of the arc plate 7, thereby improving the fixing effect of the support frame 1.

[0024] The driving assembly includes a first rack 13 and a second rack 14, the first rack 13 is slidably connected to the bottom surface of the connecting rod 9, the side wall of the first rack 13 is fixedly connected to a first spring through a bracket, the bottom end of the first spring is fixedly connected to the inner wall of the connecting rod 9, the top surface of the second rack 14 is fixedly connected to the piston 15, and a gear is meshed between the first rack 13 and the second rack 14; in the present application, during the process of the arc plate 7 being pushed, the connecting rod 9 will slide in the connecting groove 10, at this time the first rack 13 will contact the bottom surface of the connecting groove 10, and then be pushed by the connecting groove 10, so that the first rack 13 drives the gear to rotate, at this time the second rack 14 will move downward, and then drive the piston 15 to move downward, thereby sucking the air in the suction cup 12 to strengthen the fixing effect of the suction cup 12, and through the above-mentioned mechanism, the effect of exhausting air in the suction cup 12 can be achieved during the movement of the arc plate 7.

[0025] The bottom surface of the permanent magnet 2 is provided with an annular moving groove 17, and a hollow hollow ring 18 is sealed and slidably connected in the moving groove 17. The top of the hollow ring 18 is opened, and a group of exhaust holes 19 are provided on the inner wall of the hollow ring 18. The inner wall of the moving groove 17 is fixedly connected with a second spring through a bracket, and the bottom end of the second spring is fixedly connected to the hollow ring 18. A hollow groove 22 is provided in the permanent magnet 2, and an air inlet groove 23 connected to the moving groove 17 is provided on the inner wall of the hollow groove 22. , an air intake mechanism is provided in the hollow groove 22; since the permanent magnet 2 needs to be adsorbed on the lower cover plate of the main beam, if there are impurities on the lower cover plate of the main beam, it will affect the adsorption effect of the permanent magnet 2. Through the above mechanism, when the permanent magnet 2 is adsorbed on the lower cover plate, the gas in the hollow groove 22 can be discharged into the movable groove 17 with the help of the air intake mechanism, and then enters into the hollow ring 18, and finally blown out from the exhaust hole 19 to the cover plate, thereby blowing away the impurities on the cover plate to improve the adsorption effect of the permanent magnet 2 on the cover plate.

[0026] The air intake mechanism includes a push plate 21 that slides in a sealed manner with the inner wall of the hollow groove 22, a third spring is fixedly connected between the top surface of the push plate 21 and the inner wall of the hollow groove 22, and a slide rod 20 is slidably connected to the bottom surface of the permanent magnet 2, and the top end of the slide rod 20 is fixedly connected to the push plate 21; in the process of the permanent magnet 2 being adsorbed on the cover plate, the slide rod 20 will first contact the cover plate, and then the slide rod 20 will be pushed by the cover plate, at this time the slide rod 20 will drive the push plate 21 to move, and at this time the push plate 21 will push the gas in the hollow groove 22 from the air intake groove 23 into the movable groove 17, and then blown onto the cover plate from the exhaust hole 19. Through the above mechanism, the gas can be blown onto the cover plate from the exhaust hole 19 during the adsorption of the permanent magnet 2.

[0027] Embodiment 2: Figure 6As shown, the exhaust hole 19 is tilted downward, and the inner wall of the hollow ring 18 is twisted with a sealing plate 25 for sealing the exhaust hole 19 through a torsion spring; in the present application, when the gas enters the hollow ring 18 and the air pressure in the hollow ring 18 reaches a certain value, all the sealing plates 25 will be pushed to open at the same time, so that the gas can be evenly blown onto the cover plate from the tilted exhaust hole 19, thereby improving the uniformity of the gas blowing.

[0028] like Figure 7 As shown, a method for testing the self-weight stress of a crane main beam is provided. The method adopts the above-mentioned device for testing the self-weight stress of a crane main beam. The method comprises the following steps: S1: Install the self-weight stress test device on the lower cover plate of the crane main beam, near the middle of the main beam span, turn on the indicating laser, and make the laser line parallel to the x-axis direction of the main beam. At this time, use the permanent magnet 2 to fix the self-weight stress test device on the lower cover plate of the main beam; S2: Adjust the support beam 3 so that the support beam 3 is along the y-axis direction of the main beam, and adjust the knob 5 so that the support beam 3 drives the ultrasonic surface wave sensor 4 to fit on the lower cover plate of the crane main beam; S3: complete the excitation and reception of an ultrasonic surface wave between the two ultrasonic surface wave sensors 4, record the propagation time t0 of the ultrasonic surface wave, the distance between the two ultrasonic surface wave sensors 4 is s, and calculate the propagation speed v0=s / t0 of the ultrasonic surface wave. Since the length of the main beam is much larger than the width of the main beam, the self-weight stress along the y-axis direction can be ignored. Therefore, the speed v0 at this time is taken as the propagation speed of the ultrasonic surface wave at zero stress. S4: Adjust the knob 5 so that the support beam 3 drives the ultrasonic surface wave sensor 4 away from the lower cover plate of the main beam, adjust the support beam 3 so that the support beam 33 is along the x-axis direction of the main beam, and adjust the knob 5 so that the support beam 3 drives the ultrasonic surface wave sensor 4 to fit on the lower cover plate of the crane main beam; S5: completing the excitation and reception of an ultrasonic surface wave between the two ultrasonic surface wave sensors 4, recording the propagation time t1 of the ultrasonic surface wave, the distance between the two ultrasonic surface wave sensors 4 is s, and calculating the propagation speed v1=s / t1 of the ultrasonic surface wave; S6: Perform stress testing on the crane, load the crane, and use a stress tester to measure the stress of the crane main beam under load. At the same time, complete the excitation and reception of ultrasonic surface waves between the two ultrasonic surface wave sensors 4, record the propagation time t2 of the ultrasonic surface wave, and calculate the propagation speed v2=s / t2 of the ultrasonic surface wave; S7: The relationship between the velocity of ultrasonic surface waves and stress is as follows:

[0029] In formula 1, and are the principal stresses of the surface, is the velocity of the ultrasonic surface wave when there is no stress, is the velocity of the ultrasonic surface wave propagating along the direction of the principal stress, and are the acoustic elastic constants related to the material.

[0030] Since the length of the crane main beam is much greater than its width, the stress along the y-axis when lifting the load can be ignored, that is, Equation 1 becomes Equation 2:

[0031] Substituting the stress data in this patent, the velocity v0 is measured in step S3, and the velocity v1 is measured in step S5. Substituting them into equation 2, we can get equation 3:

[0032] According to the velocity v2 measured in step S6, the corresponding stress relationship 4 is:

[0033] Combining equation 3 and equation 4, we get:

[0034] Substituting the measured data, the acoustic elastic constant k1 can be calculated. Substituting k1 into formula 3, the self-weight stress of the crane main beam can be calculated.

[0035] Working principle: The self-weight stress test device is installed on the lower cover plate of the crane main beam, near the middle of the main beam span. In order to facilitate the adjustment of the installation direction of the self-weight stress test device, turn on the laser transmitter 6 so that the laser line is parallel to the x-axis direction of the main beam. At this time, the self-weight stress test device is fixed to the lower cover plate of the main beam using the permanent magnet 2 (the crane main beam is usually made of ferromagnetic material), and the bracket crossbeam 3 is adjusted so that the bracket crossbeam 3 is along the y-axis direction of the main beam. The knob 5 is adjusted so that the bracket crossbeam 3 drives the ultrasonic surface wave sensor 4 to fit on the lower cover plate of the crane main beam, so that the two ultrasonic surface wave sensors 4 complete an ultrasonic surface wave excitation and reception, and record the excitation and reception information. Since the length of the main beam is much greater than the width of the main beam, the self-weight stress along the y-axis direction can be ignored. The knob 5 is adjusted so that the bracket crossbeam 3 drives the ultrasonic surface wave sensor 4 away from the lower cover plate of the crane main beam, so that the bracket crossbeam 3 can rotate freely. Adjust the support beam 3 so that the support beam 3 is along the x-axis direction of the main beam, adjust the knob 5 so that the support beam 3 drives the ultrasonic surface wave sensor 4 to fit on the lower cover plate of the crane main beam, complete the excitation and reception of ultrasonic surface waves between the two ultrasonic surface wave sensors 4, record the excitation and reception information, perform the stress test of the crane, load the crane, and use a stress tester (such as a resistance strain stress tester or a fiber grating stress tester) to measure the stress of the crane main beam under the load state. At the same time, complete the excitation and reception of ultrasonic surface waves between the two ultrasonic surface wave sensors 4, record the excitation and reception information, and finally obtain the self-weight stress value of the crane main beam through the information calculated by the test method. This patent can complete the calibration of the acoustic elastic constant k1 and the test of the self-weight stress of the crane main beam under the premise that the main beam material parameters and temperature are unknown; In order to facilitate the adjustment of the installation direction of the self-weight stress testing device, the laser line needs to be parallel to the x-axis direction of the main beam. However, manual operation is prone to errors, resulting in the laser line not being parallel to the x-axis direction of the main beam, which means that the support frame 1 is not parallel to the x-axis direction of the main beam. Since the support frame 1 is adsorbed on the lower cover plate of the main beam by the permanent magnet 2, the position of the support frame 1 is not easy to adjust at this time, which affects the subsequent adjustment of the installation direction of the self-weight stress testing device. There will be deviations. In this application, after the support frame 1 is fixed on the lower cover plate of the main beam by the permanent magnet 2 through the above-mentioned mechanism, when the position of the support frame 1 needs to be adjusted, it is only necessary to rotate the support frame 1 to let the connecting rod 9 slide in the slide groove 8. At this time, the support frame 1 will rotate in a circle, thereby adjusting the position of the support frame 1 to be parallel to the x-axis direction of the main beam; After the support frame 1 is adjusted to a suitable position, the present application can press the support frame 1 so that the arc plate 7 pushes the connecting rod 9. At this time, the connecting rod 9 will move in the connecting groove 10. At this time, the gas in the connecting groove 10 will enter the connecting rod 9 from the air inlet hole and push the connecting column 11, so that the connecting column 11 pushes the suction cup 12 to be adsorbed on the arc plate 7. At this time, the connecting rod 9 is fixed on the arc plate 7, so that the support frame 1 is fixed, thereby achieving the effect of fixing the adjusted support frame 1; after the suction cup 12 is adsorbed on the inner wall of the arc plate 7, the present application can use the driving assembly to drive the piston 15 to slide to the side close to the permanent magnet 2. At this time, the piston 15 will suck the gas in the suction cup 12, so that the piston 15 is more firmly adsorbed on the inner wall of the arc plate 7, thereby improving the fixing effect of the support frame 1; In the process of the arc plate 7 being pushed, the connecting rod 9 will slide in the connecting groove 10. At this time, the first rack 13 will contact the bottom surface of the connecting groove 10, and then be pushed by the connecting groove 10, so that the first rack 13 drives the gear to rotate. At this time, the second rack 14 will move downward, and then drive the piston 15 to move downward, thereby sucking the air in the suction cup 12 to strengthen the fixing effect of the suction cup 12. The above mechanism can achieve the effect of exhausting air in the suction cup 12 during the movement of the arc plate 7; since the permanent magnet 2 needs to be adsorbed on the lower cover plate of the main beam, if there are impurities on the lower cover plate of the main beam, it will affect the adsorption effect of the permanent magnet 2. The above mechanism can be used to absorb the air in the suction cup 12 when the arc plate 7 moves. When the permanent magnet 2 is on the cover plate, the gas in the hollow groove 22 can be discharged into the movable groove 17 with the help of the air intake mechanism, and then enters into the hollow ring 18, and finally blown out from the exhaust hole 19 to the cover plate, so as to blow away the impurities on the cover plate to improve the effect of the permanent magnet 2 adsorbing on the cover plate; in the process of the permanent magnet 2 adsorbing on the cover plate, the slide bar 20 will first contact the cover plate, and then the slide bar 20 will be pushed by the cover plate, at this time the slide bar 20 will drive the push plate 21 to move, at this time the push plate 21 will push the gas in the hollow groove 22 from the air intake groove 23 into the movable groove 17, and then blown onto the cover plate from the exhaust hole 19, through the above mechanism, the gas can be blown from the exhaust hole 19 to the cover plate during the adsorption of the permanent magnet 2.

[0036] The above-mentioned front, back, left, right, top and bottom are all based on the figures in the specification. Figure 1 As a benchmark, according to the person's observation perspective, the side of the device facing the observer is defined as the front, the left side of the observer is defined as the left, and so on.

[0037] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the scope of protection of the present invention.

[0038] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A crane main beam deadweight stress testing device, comprising a support frame (1) consisting of two mutually perpendicular support arms; characterized in that: A group of permanent magnets (2) are arranged on the bottom surface of the support frame (1), and a pair of symmetrical laser emitters (6) are mounted on the support frame (1); A knob (5) is movably connected to the central portion of the support frame (1); a support crossbeam (3) is fixedly connected to the knob (5); and a pair of ultrasonic surface wave sensors (4) are fixedly connected to the bottom surface of the support crossbeam (3).

2. A crane main beam deadweight stress testing device according to claim 1, characterized in that: A hollow arc-shaped plate (7) is fixedly connected to the bottom surface of the support frame (1), a slide groove (8) is provided on the bottom surface of the arc-shaped plate (7), a connecting rod (9) is slidably connected to the inner wall of the slide groove (8), and the connecting rod (9) is arranged on the permanent magnet (2).

3. A crane main beam deadweight stress testing device according to claim 2, characterized in that: The top surface of the connecting rod (9) is sealingly and slidably connected to a hollow connecting column (11), the top surface of the connecting column (11) is fixedly connected to a suction cup (12), a connecting groove (10) is provided in the permanent magnet (2), the connecting rod (9) is sealingly and slidably connected to the top surface of the permanent magnet (2) and extends into the connecting groove (10), the interior of the connecting rod (9) is a hollow structure, the top end of the connecting rod (9) is open, and the bottom end of the connecting rod (9) is provided with an air inlet hole.

4. A crane main beam deadweight stress testing device according to claim 3, characterized in that: One end of the suction cup (12) close to the connecting column (11) is connected to a hollow conduit (24), a piston (15) is sealingly and slidably connected inside the conduit (24), a limiting ring (16) located above the piston (15) is fixedly connected to the inner wall of the conduit (24), and a driving component for driving the piston (15) to move is arranged inside the conduit (24).

5. A crane main beam deadweight stress testing device according to claim 4, characterized in that: The driving assembly comprises a first rack (13) and a second rack (14), wherein the first rack (13) is slidably connected to the bottom surface of the connecting rod (9), a first spring is fixedly connected to the side wall of the first rack (13) via a bracket, the bottom end of the first spring is fixedly connected to the inner wall of the connecting rod (9), the top surface of the second rack (14) is fixedly connected to the piston (15), and a gear is meshed between the first rack (13) and the second rack (14).

6. A crane main beam deadweight stress testing device according to claim 5, characterized in that: The bottom surface of the permanent magnet (2) is provided with an annular movable groove (17), a hollow hollow ring (18) is sealed and slidably connected in the movable groove (17), the top end of the hollow ring (18) is opened, and the inner wall of the hollow ring (18) is provided with a group of exhaust holes (19), the inner wall of the movable groove (17) is fixedly connected with a second spring through a bracket, the bottom end of the second spring is fixedly connected to the hollow ring (18), the permanent magnet (2) is provided with a hollow groove (22), the inner wall of the hollow groove (22) is provided with an air intake groove (23) connected with the movable groove (17), and an air intake mechanism is provided in the hollow groove (22).

7. A crane main beam deadweight stress testing device according to claim 6, characterized in that: The air intake mechanism comprises a push plate (21) which is sealed and slidable with the inner wall of the hollow groove (22); a third spring is fixedly connected between the top surface of the push plate (21) and the inner wall of the hollow groove (22); a slide rod (20) is slidably connected to the bottom surface of the permanent magnet (2); and a top end of the slide rod (20) is fixedly connected to the push plate (21).

8. The device for testing the deadweight stress of a crane main beam according to claim 7, characterized in that: The exhaust hole (19) is arranged to be inclined downward, and the inner wall of the hollow ring (18) is twisted with a sealing plate (25) for sealing the exhaust hole (19) via a torsion spring.

9. A method for testing the self-weight stress of a crane main beam, the method using a device for testing the self-weight stress of a crane main beam as claimed in claim 8, characterized in that: The method comprises the following steps: S1: Install the self-weight stress test device on the lower cover plate of the crane main beam, near the middle of the main beam span, turn on the laser transmitter (6), and make the laser line parallel to the x-axis direction of the main beam. At this time, use the permanent magnet (2) to fix the self-weight stress test device to the lower cover plate of the main beam; S2: adjusting the support crossbeam (3) so that the support crossbeam (3) is along the y-axis direction of the main beam, and adjusting the knob (5) so that the support crossbeam (3) drives the ultrasonic surface wave sensor (4) to fit on the lower cover plate of the crane main beam; S3: completing the excitation and reception of an ultrasonic surface wave between the two ultrasonic surface wave sensors (4), recording the propagation time t0 of the ultrasonic surface wave, the distance between the two ultrasonic surface wave sensors (4) is s, and calculating the propagation speed v0=s / t0 of the ultrasonic surface wave. Since the length of the main beam is much greater than the width of the main beam, the self-weight stress along the y-axis direction is negligible, and therefore, the speed v0 at this time is taken as the propagation speed of the ultrasonic surface wave at zero stress; S4: adjusting the knob (5) so that the support crossbeam (3) drives the ultrasonic surface wave sensor (4) away from the lower cover plate of the main beam, adjusting the support crossbeam (3) so that the support crossbeam (3) is along the x-axis direction of the main beam, and adjusting the knob (5) so that the support crossbeam (3) drives the ultrasonic surface wave sensor (4) to fit on the lower cover plate of the crane main beam; S5: completing one ultrasonic surface wave excitation and reception between the two ultrasonic surface wave sensors (4), recording the ultrasonic surface wave propagation time t1, the distance between the two ultrasonic surface wave sensors (4) is s, and calculating the ultrasonic surface wave propagation speed v1=s / t1.

10. A method for testing the deadweight stress of a crane main beam according to claim 9, characterized in that: The method further comprises the steps of: S6: Perform stress testing on the crane, load the crane, and use a stress tester to measure the stress of the crane main beam under load. At the same time, complete the excitation and reception of an ultrasonic surface wave between two ultrasonic surface wave sensors (4), record the propagation time t2 of the ultrasonic surface wave, and calculate the propagation speed v2=s / t2 of the ultrasonic surface wave; S7: Calculate based on the obtained excitation and received recorded data to obtain the self-weight stress of the crane main beam.

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