A method and system for safety assessment and early warning of tower cranes

Abstract

This invention relates to a safety assessment and early warning method for tower cranes, characterized by the following steps: S1. Selecting several groups of tower crane tilt angles, establishing a correspondence between the boom length axis and the tilt baseline at different angles for different loads under each group of tilt angles, and obtaining a correspondence table, where the included angle is defined as the deflection angle; S2. During tower crane operation, detecting the tower crane tilt angle, boom load, and boom orientation, and calculating the current boom deflection angle based on the boom orientation and the orientation of the tower tilt baseline; S3. Retrieving the corresponding deflection torque value from the correspondence table based on the boom load and the current deflection angle; S4. Comparing the deflection torque value with a preset torque warning value, generating an early warning signal when the deflection torque value exceeds the torque warning value. This method improves the safety of tower crane operation and prevents accidents.

Description

Technical Field

[0001] This invention relates to the field of engineering machinery technology, specifically to a method and system for safety assessment and early warning of tower cranes. Background Technology

[0002] Tower cranes are characterized by high lifting height, large working radius, and easy assembly and disassembly, and are widely used in civil construction and industrial construction.

[0003] Tower cranes are mainly composed of a base, tower body, turntable, boom, lifting mechanism, counterweight boom, and operator's cab. The base and tower body provide support, the turntable drives the boom and counterweight boom to rotate and provides braking torque to keep the boom in its current angle position to prevent it from swinging freely, and the lifting mechanism is used to lift goods.

[0004] When the tower is perfectly vertical, the turntable is perfectly horizontal, and the boom exerts no yaw torque on the turntable. However, when the tower tilts, the turntable's horizontal position is disrupted, and the boom exerts a significant yaw torque on it, especially when the boom is heavily loaded. This causes additional stress on the turntable. To ensure the boom swings smoothly or maintains its current angle, the turntable needs to output torque to counteract the yaw torque.

[0005] However, when the load on the boom is large or the tilt angle of the tower is large, the deflection torque of the boom will become very large, which will put a great burden on the turntable and may damage the turntable. The deflection torque of the boom may even exceed the maximum output torque of the turntable, causing the boom to go out of control and resulting in a serious safety accident.

[0006] For the reasons mentioned above, there is an urgent need to design a scheme for monitoring and early warning of the deflection torque of the crane boom. Summary of the Invention

[0007] Based on the above description, the present invention provides a method and system for safety assessment and early warning of tower cranes, so as to realize the assessment and early warning of the deflection torque of the crane boom.

[0008] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0009] A method for safety assessment and early warning of tower cranes includes the following steps:

[0010] S1. Select several groups of tower crane inclination angles, and establish the correspondence between the boom length axis and the inclination baseline at different angles for different loads under each group of tower inclination angles, and obtain the correspondence table. The included angle is defined as the boom deflection angle.

[0011] S2. When the tower crane is working, the tower body tilt angle, the load of the boom, and the orientation of the boom are detected. The current deflection angle of the boom is calculated based on the orientation of the boom and the orientation of the tower body tilt baseline.

[0012] S3. Based on the current tower tilt angle, boom deflection angle, and boom load, retrieve the corresponding deflection torque value from the corresponding relationship table;

[0013] S4. Compare the deflection torque value with the preset torque warning value, and generate a warning signal when the deflection torque value is greater than the torque warning value.

[0014] As a preferred solution: set correction factors X1 and X2 for the upward and downward tilt of the crane boom, respectively, where X1 = (1 + K * θ1) and X2 = (1 - K * θ2), where K is a constant, θ1 is the upward tilt angle of the crane boom, and θ2 is the downward tilt angle of the crane boom; when the tower crane is working, detect the tilt angle of the crane boom. If the crane boom is tilted, obtain the correction factor according to its tilt angle, multiply the retrieved deflection torque value with the correction factor to obtain the corrected deflection torque value, compare the corrected deflection torque value with the torque warning value, and generate a warning signal when the former is greater than the latter.

[0015] As a preferred option: set a first torque warning value and a second torque warning value, wherein the first torque warning value is less than the second torque warning value. When the deflection torque is greater than the first torque warning value, the balancing torque is increased by adding counterweight to the tower crane's counterweight arm. When the deflection torque is greater than the second torque warning value, a warning signal is issued.

[0016] As a preferred solution: when the tower body is tilted, the tilt angle of the tower body is monitored in real time during tower crane operation. When the tilt angle of the tower body changes, a new deflection torque value is retrieved based on the current tilt angle of the tower body, the orientation of the crane arm, and the load. The new deflection torque value is compared with the torque warning value. A warning signal is generated when the former is greater than the latter.

[0017] A tower crane safety assessment and early warning system includes:

[0018] The first tilt angle detection device is used to detect the tilt direction and tilt angle of the tower body of the tower crane and output the detection results.

[0019] The rotation angle detection device is used to detect the angular position of the crane boom and the angle through which the crane boom has rotated, and outputs the detection results.

[0020] A load detection device is used to detect the load on the crane boom and output the detection results;

[0021] The control device is connected to the first tilt angle detection device, the rotation angle detection device, and the load detection device. It receives the detection results output by the first tilt angle detection device, the second tilt angle detection device, and the load detection device, calculates the deflection angle of the lifting arm based on the tilt angle of the tower body and the angle position of the lifting arm, matches the current deflection torque of the lifting arm with the load of the lifting arm, compares the deflection torque of the lifting arm with the torque warning value, and generates a warning signal when the former is greater than the latter.

[0022] As a preferred embodiment, the system further includes a second tilt angle detection device connected to the control device. The second tilt angle detection device is used to detect the vertical tilt angle of the tower crane's boom and output the detection result to the control device. The control device matches a correction factor based on the vertical tilt angle of the boom, multiplies the retrieved deflection torque value by the correction factor to obtain the corrected deflection torque value, and then compares the corrected deflection torque value with a torque warning value. If the former is greater than the latter, a warning signal is generated.

[0023] As a preferred embodiment, the system further includes a counterweight adjustment mechanism. This mechanism comprises a guide rail mounted on the balance arm along its length, a counterweight block mounted on the guide rail, the counterweight block being slidably connected to the guide rail and capable of sliding back and forth along the length of the guide rail. A drive motor is also mounted on the balance beam, and a lead screw is coaxially connected to the output shaft of the drive motor. The lead screw is parallel to the guide rail, passes through the guide rail, and is threadedly connected to the counterweight block. A connecting block is provided at the end of the lead screw, the block being fixed to the balance beam, and the end being rotatably connected to the connecting block.

[0024] As a preferred embodiment, the first tilt angle detection device includes a gyroscope sensor installed at the center of the tower body.

[0025] As a preferred embodiment: the second tilt angle detection device includes a laser emitting device mounted at the tower tip and a laser receiving device mounted at the front end of the jib. The laser emitting device includes an adjusting motor and a laser emitter. The adjusting motor is mounted on the tower tip, and the housing of the laser emitter is connected and fixed to the rotating shaft of the adjusting motor via a connecting part. The laser emitter faces the laser receiving device, and the motor is connected to the first motor drive module. Compared with the prior art, the technical solution of this application has the following beneficial technical effects: This solution can monitor the deflection torque of the jib of the tower crane in real time, and can combine the tower tilt angle, the load of the jib, and the swing angle of the jib to conduct targeted and refined safety assessments and early warnings, greatly improving the safety of tower crane operation and effectively preventing safety accidents. Attached Figure Description

[0026] Figure 1 This is a flowchart of the method in Example 1;

[0027] Figure 2 This is the circuit schematic diagram for Example 2;

[0028] Figure 3 This is a schematic diagram of the crane structure in Example 2;

[0029] Figure 4 for Figure 3 Enlarged view of part A in the image;

[0030] Figure 5 for Figure 3 Enlarged view of part B in the image.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1. Base; 2. Tower body; 3. Turntable; 4. Operator's cab; 5. Lifting boom; 6. Counterweight boom; 7. Lifting hook; 8. Weighing pallet; 9. Guide rail; 10. Counterweight block; 11. Connecting block; 12. Lead screw; 13. Drive motor; 14. Tower tip; 15. Laser emitter; 16. Connecting part; 17. Adjusting motor; 18. Rotating shaft; 19. Laser receiver; 20. Gyroscope sensor; 21. Angle encoder. Detailed Implementation

[0033] Example 1:

[0034] A method for safety assessment and early warning of tower cranes, characterized by the following steps:

[0035] S1. Select several groups of tower crane inclination angles, and establish the correspondence between the boom length axis and the inclination baseline at different angles for different loads under each group of tower inclination angles, and obtain the correspondence table. The included angle is defined as the boom deflection angle.

[0036] A scaled-down model of a tower crane was built, and experiments were conducted using this model. Specifically:

[0037] Adjust the tower body of the scaled-down model to the first tilt angle. At the current tilt angle of the tower body, determine the tilt baseline of the tower body. The tilt baseline is based on the rotating circular surface of the turntable. Select the point with the lowest height on the circumference edge of the circular surface and connect this point with the center of the circular surface. This line is the tilt baseline.

[0038] Using the tilted baseline as the zero angle line, the current angle of the crane boom is detected by an angle encoder installed on the turntable. This angle is the angle between the crane boom length axis and the tilted baseline.

[0039] Under the current tower tilt angle, and with the first load, swing the boom to different angles and measure the deflection torque of the boom at different swing angles; repeat the above steps under the second load, third load, and so on.

[0040] Change the tower body to the second tilt angle, and repeat the above steps under the first load, second load, third load, and so on.

[0041] This yields the corresponding relationships between the tower tilt angle, the boom deflection angle, the boom load, and the boom deflection torque, resulting in a corresponding relationship table.

[0042] S2. When the tower crane is working, the tower body tilt angle, the load of the boom, and the orientation of the boom are detected. The current deflection angle of the boom is calculated based on the orientation of the boom and the orientation of the tower body tilt baseline.

[0043] The tilt angle of the tower is detected by a gyroscope sensor. The weight of the goods loaded on a weighing pallet is obtained, which is the load capacity of the boom. The swing angle of the boom is detected by an angle encoder. The current deflection angle of the boom is calculated based on the orientation of the boom and the orientation of the tower tilt baseline.

[0044] S3. Based on the current tower tilt angle, boom deflection angle, and boom load, retrieve the corresponding deflection torque value from the corresponding relationship table;

[0045] S4. Compare the deflection torque value with the preset torque warning value, and generate a warning signal when the deflection torque value is greater than the torque warning value.

[0046] This allows for real-time monitoring and early warning of the crane boom deflection torque, preventing safety accidents.

[0047] Considering that the crane boom may tilt upwards or downwards in the actual working environment, under the same load, tilting upwards or downwards will cause the deflection torque of the crane boom to change. Therefore, when evaluating the deflection torque, the tilt state of the crane boom needs to be taken into account.

[0048] In this embodiment: correction factors X1 and X2 are set for the upward and downward tilt of the crane boom, respectively, where X1 = (1 + K * θ1) and X2 = (1 - K * θ2), where K is a constant, θ1 is the upward tilt angle of the crane boom, and θ2 is the downward tilt angle of the crane boom. When the tower crane is working, the tilt angle of the crane boom is detected. If the crane boom is in a tilted state, the correction factor is obtained according to its tilt angle. The retrieved deflection torque value is multiplied by the correction factor to obtain the corrected deflection torque value. The corrected deflection torque value is compared with the torque warning value. If the former is greater than the latter, a warning signal is generated.

[0049] In this embodiment: a first torque warning value and a second torque warning value are set, wherein the first torque warning value is less than the second torque warning value. When the deflection torque is greater than the first torque warning value, the balancing torque is increased by adding counterweight to the tower crane balance arm. When the deflection torque is greater than the second torque warning value, a warning signal is issued.

[0050] When the deflection torque reaches the first torque warning value, the counterweight of the balance arm is increased to increase the balancing torque of the balance arm on the turntable, thereby partially offsetting or weakening the deflection torque of the crane arm on the turntable, protecting the turntable, improving safety, and reducing unnecessary warnings. However, when the above measures cannot effectively offset the deflection torque, the deflection torque continues to increase to the second torque warning value. At this time, the deflection torque of the crane arm is large and may have an adverse effect on the turntable, thus triggering a production warning signal.

[0051] As a preferred solution: when the tower body is tilted, the tilt angle of the tower body is monitored in real time during tower crane operation. When the tilt angle of the tower body changes, a new deflection torque value is retrieved based on the current tilt angle of the tower body, the orientation of the crane arm, and the load. The new deflection torque value is compared with the torque warning value. A warning signal is generated when the former is greater than the latter.

[0052] Example 2:

[0053] A tower crane safety assessment and early warning system includes:

[0054] The first tilt angle detection device is used to detect the tilt direction and tilt angle of the tower body 2 of the tower crane and output the detection results.

[0055] Reference Figure 3 In this embodiment, the first tilt angle detection device includes a gyroscope sensor 20 installed in the center of the tower body 2. When the tower body 2 tilts, the gyroscope sensor 20 outputs the corresponding angle and direction information.

[0056] The rotation angle detection device is used to detect the angular position of the lifting arm 5 and the angle through which the lifting arm 5 has rotated, and outputs the detection results.

[0057] Reference Figure 3 In this embodiment, the rotation angle detection device is an angle encoder 21. The angle encoder 21 is installed at the bottom of the turntable 3 and is connected to the turntable 3 in a transmission manner. When the turntable 3 rotates, it will drive the angle encoder 21 to rotate synchronously, thereby changing the angle value output by the angle encoder 21. The angle through which the lifting boom 5 has rotated can be known by the change in the angle value.

[0058] A load detection device is used to detect the load on the lifting boom 5 and output the detection results;

[0059] Reference Figure 4 In this embodiment, the load detection device is a weighing pallet 8, which is connected to the lifting hook 7 of the lifting arm 5 via a cable. When goods are placed on the weighing pallet 8, the weighing pallet 8 will output the weight information of the goods.

[0060] The control device is connected to the first tilt angle detection device, the rotation angle detection device, and the load detection device. It is used to receive the detection results output by the first tilt angle detection device, the rotation angle detection device, and the load detection device, and calculate the deflection angle of the lifting boom 5 based on the tilt angle of the tower body 2 and the angular position of the lifting boom 5. It also matches the current deflection torque of the lifting boom 5 with the load of the lifting boom 5, compares the deflection torque of the lifting boom 5 with the torque warning value, and generates a warning signal when the former is greater than the latter.

[0061] Reference Figure 2 The control device in this embodiment includes a main control module, and also includes a signal acquisition module, an alarm module, a first motor drive module, a second motor drive module, an alarm module, a communication module, and a power supply module connected to the main control module.

[0062] The signal output terminals of the gyroscope sensor 20, angle encoder 21, and weighing tray 8 are connected to the input terminal of the signal acquisition module. The weighing tray 8 and the signal acquisition module can be connected by a cable or wirelessly (using a wireless weighing tray 8).

[0063] In this embodiment, a second tilt angle detection device connected to the control device is also included. The second tilt angle detection device is used to detect the vertical tilt angle of the boom 5 of the tower crane and output the detection result to the control device. The control device matches a correction factor according to the vertical tilt angle of the boom 5, and multiplies the retrieved deflection torque value with the correction factor to obtain the corrected deflection torque value. Then, the corrected deflection torque value is compared with the torque warning value. When the former is greater than the latter, a warning signal is generated.

[0064] Reference Figure 3 and Figure 5 In this embodiment, the second tilt angle detection device includes a laser emitting device mounted on the tower tip 14 and a laser receiving device 19 mounted on the front end of the lifting arm 5. The laser emitting device includes an adjusting motor 17 and a laser emitter 15. The adjusting motor 17 is mounted on the tower tip 14. The housing of the laser emitter 15 is connected and fixed to the rotating shaft 18 of the adjusting motor 17 via a connecting part 16. By controlling the rotation of the adjusting motor 17, the laser emitter 15 can be driven to rotate, thereby adjusting the pitch angle of the laser emitter 15. The laser emitter 15 faces the laser receiving device 19.

[0065] Adjust motor 17 is connected to the first motor drive module.

[0066] The laser transmitter 15 is connected to the main control module, and the laser receiver 19 is connected to the signal sampling module. The main control module sends a command signal to the laser transmitter 15 to make the laser receiver emit a laser signal. After receiving the laser signal, the laser receiver 19 outputs a feedback signal to the signal acquisition module.

[0067] When the lifting boom 5 is unloaded, aligning the laser emitter 15 with the laser receiver 19 completes the calibration of the laser system. When the lifting boom 5 is under load, if it tilts upwards or downwards, the laser receiver 19 will not receive the laser signal. When the laser receiver cannot receive the laser signal, the main control module sends a pulse signal to the adjusting motor 17, causing the adjusting motor 17 to rotate stepwise, thereby slowly adjusting the pitch angle of the laser emitter 15 until the laser receiver 19 receives the laser signal again. The main control module can determine the adjustment angle of the laser emitter 15 by counting the number of pulse signals and the step size of the adjusting motor 17, and considers this angle as the tilt angle of the lifting boom 5. This detection method can comprehensively detect the tilt angle of the lifting boom 5 itself and the tilt angle caused by the bending of the lifting boom 5, and the detection results are more consistent with the actual situation.

[0068] In this embodiment, a counterweight adjustment mechanism is also included. This mechanism includes a guide rail 9 mounted on the balance arm 6 along its length. A counterweight block 10 is mounted on the guide rail 9, and the counterweight block 10 is slidably connected to the guide rail 9 and can slide back and forth along the length of the guide rail 9. A drive motor 13 is also mounted on the balance beam. The output shaft of the drive motor 13 is coaxially connected to a lead screw 12, which is parallel to the guide rail 9. The lead screw 12 passes through the guide rail 9 and is threadedly connected to the counterweight block 10. A connecting block 11 is provided at the end of the lead screw 12, which is fixed to the balance beam. The end of the lead screw 12 is rotatably connected to the connecting block 11. The rotation of the drive motor 13 drives the lead screw 12 to rotate synchronously, thereby driving the counterweight block 10 to slide along the guide rail 9. This allows adjustment of the position of the counterweight block 10 on the balance beam, thus changing the center of gravity of the balance beam. Therefore, by changing the position of the balance beam, the reaction torque of the balance beam can be changed, and by increasing the reaction torque, the deflection torque of the lifting arm 5 can be better countered.

[0069] The drive motor 13 is connected to the second motor drive module.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A safety assessment and early warning method for tower cranes, characterized in that, Includes the following steps: S1. Select several groups of tower crane inclination angles, and establish the correspondence between the boom length axis and the inclination baseline at different angles for different loads under each group of tower inclination angles, and obtain the correspondence table. The included angle is defined as the boom deflection angle. S2. When the tower crane is working, the tower body tilt angle, the load of the boom, and the orientation of the boom are detected. The current deflection angle of the boom is calculated based on the orientation of the boom and the orientation of the tower body tilt baseline. S3. Based on the current tower tilt angle, boom deflection angle, and boom load, retrieve the corresponding deflection torque value from the corresponding relationship table; S4. Compare the deflection torque value with the preset torque warning value, and generate a warning signal when the deflection torque value is greater than the torque warning value; Correction factors X1 and X2 are set for the upward and downward tilt of the crane boom, respectively, where X1 = (1 + K) / ( ... θ1), X2 = (1-K) θ2), where K is a constant, θ1 is the upward tilt angle of the boom, and θ2 is the downward tilt angle of the boom; when the tower crane is working, the tilt angle of the boom is detected. If the boom is tilted, a correction factor is obtained based on its tilt angle. The deflection torque value is multiplied by the correction factor to obtain the corrected deflection torque value. The corrected deflection torque value is compared with the torque warning value. If the former is greater than the latter, a warning signal is generated. A first torque warning value and a second torque warning value are set, wherein the first torque warning value is less than the second torque warning value. When the deflection torque is greater than the first torque warning value, the balancing torque is increased by adding counterweight to the tower crane's counterweight boom. When the deflection torque is greater than the second torque warning value, a warning signal is issued.

2. The tower crane safety assessment and early warning method according to claim 1, characterized in that: When the tower is tilted, the tilt angle of the tower is monitored in real time during tower crane operation. When the tilt angle of the tower changes, a new deflection torque value is retrieved based on the current tilt angle of the tower, the direction of the jib, and the load. The new deflection torque value is compared with the torque warning value. If the former is greater than the latter, a warning signal is generated.

3. A tower crane safety assessment and early warning system, used to perform the method described in any one of claims 1-2, characterized in that, include: The first tilt angle detection device is used to detect the tilt direction and tilt angle of the tower body of the tower crane and output the detection results. The second tilt angle detection device is used to detect the vertical tilt angle of the boom of the tower crane and output the detection results to the control device. The rotation angle detection device is used to detect the angular position of the crane boom and the angle through which the crane boom has rotated, and outputs the detection results. A load detection device is used to detect the load on the crane boom and output the detection results; The control device is connected to the first tilt angle detection device, the rotation angle detection device, and the load detection device. It receives the detection results output by the first tilt angle detection device, the second tilt angle detection device, and the load detection device, calculates the deflection angle of the lifting arm based on the tilt angle of the tower body and the angle position of the lifting arm, matches the current deflection torque of the lifting arm with the load of the lifting arm, compares the deflection torque of the lifting arm with the torque warning value, and generates a warning signal when the former is greater than the latter. The control device matches a correction factor based on the vertical tilt angle of the crane boom, multiplies the retrieved deflection torque value by the correction factor to obtain the corrected deflection torque value, and then compares the corrected deflection torque value with the torque warning value. If the former is greater than the latter, a warning signal is generated.

4. The tower crane safety assessment and early warning system according to claim 3, characterized in that: It also includes a counterweight adjustment mechanism, which includes a guide rail mounted on the balance arm along the length of the balance arm, a counterweight block mounted on the guide rail, the counterweight block being slidably connected to the guide rail and capable of sliding back and forth along the length of the guide rail, a drive motor mounted on the balance arm, a lead screw coaxially connected to the output shaft of the drive motor, the lead screw being parallel to the guide rail, passing through the guide rail and threadedly connected to the counterweight block, a connecting block provided at the end of the lead screw, the connecting block being fixed to the balance arm, and the end being rotatably connected to the connecting block.

5. The tower crane safety assessment and early warning system according to claim 3, characterized in that: The first tilt angle detection device includes a gyroscope sensor installed at the center of the tower body.

6. The tower crane safety assessment and early warning system according to claim 3, characterized in that: The second tilt angle detection device includes a laser emitting device disposed at the top of the tower and a laser receiving device disposed at the front end of the crane arm. The laser emitting device includes an adjusting motor and a laser emitter. The adjusting motor is mounted on the top of the tower. The housing of the laser emitter is connected and fixed to the rotating shaft of the adjusting motor through a connecting part. The laser emitter faces the laser receiving device. The motor is connected to the first motor drive module.

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