Crane and safety index evaluation method thereof

Abstract

The invention provides a crane and a safety index evaluation method thereof, and the method comprises the steps: collecting safety factor data of the crane in real time, including an instantaneous change rate sequence of a worm gear rotation speed, a main wind direction angle and an instantaneous wind speed, and actual weight and material type of a hoisted material; calculating an operation stability index based on the instantaneous change rate sequence of the worm gear rotating speed, and obtaining a mechanical risk factor; the lateral wind load state of the crane is judged through the main wind direction angle and the instantaneous wind speed, and environmental risk factors are obtained; based on judgment of mechanical risk factors and environmental risk factors, a trigger threshold value of a locking and limiting structure is dynamically adjusted, and load risk factors are dynamically corrected; and comparing the corrected load risk factor with a preset safety threshold, and when the corrected load risk factor exceeds the preset safety threshold, dynamically adjusting the crane parameters according to at least one of the mechanical risk, the environmental risk and the load risk, thereby realizing the intelligent management of the use safety of the crane.

Description

Technical Field

[0001] This invention relates to the field of lifting equipment technology, and in particular to a crane and a method for evaluating its safety indicators. Background Technology

[0002] Lifting equipment, as essential equipment in industrial handling, construction, warehousing, and logistics, is primarily used for lifting, moving, and positioning heavy objects. Existing small or medium-sized lifting equipment typically consists of a base, support frame, crossbeam, wire rope winch mechanism, and hook. The winch mechanism drives the wire rope to raise and lower, thereby lifting the heavy object. To adapt to different operating environments, some equipment is equipped with an adjustable-length crossbeam, enabling lifting operations at varying distances. However, traditional structures still have shortcomings in terms of flexibility and safety.

[0003] In existing technologies, many hoisting mechanisms employ ordinary drums or direct motor drive, lacking effective self-locking structures. When the motor loses power, the brake fails, or the wire rope is subjected to impact, the drum may reverse, causing the hook and load to suddenly fall, easily leading to safety accidents. Furthermore, due to wear, swaying, and directional changes in the wire rope during winding or operation, the lifting process is not smooth, increasing operational risks. Therefore, improving the self-locking performance and stability of wire rope hoisting mechanisms is a problem that the industry needs to solve.

[0004] To meet the requirements of different lifting angles, existing lifting equipment typically incorporates a rotating connection between the beam and the support frame to adjust the beam's orientation. However, traditional beam rotation mechanisms often rely on gears, pins, or simple locking structures for positioning. When the equipment is subjected to external impacts, uneven load distribution, or the beam's inertia, the rotating parts are prone to shifting, causing changes in the lifting point's position, affecting lifting accuracy, and potentially leading to dangerous swaying of the load. Therefore, beam rotation mechanisms need to possess stronger positioning capabilities and resistance to external forces.

[0005] Existing lifting devices mostly use fixed pins or mechanical slots for limiting the beam. While these mechanisms can provide initial limiting, the adjustment methods are limited and rely on manual operation, making it difficult to achieve multi-level or automatic limiting. Furthermore, these structures are prone to dislocation or slippage under significant external forces, compromising the beam's stability during use. In addition, the limiting structures of some devices are complex to adjust, hindering quick switching or release of limits during operation and limiting equipment efficiency.

[0006] In the process of evaluating the safety indicators of existing cranes, only a single factor is often considered, such as whether the load, wind speed or tension exceeds the limit. There is a lack of coupling analysis between different factors, which can easily lead to blind spots in the judgment of a single indicator. Traditional methods mostly use binary judgment, which cannot achieve fine control.

[0007] In summary, existing lifting equipment still has significant shortcomings in terms of improving safety, stability of beam angle adjustment, and reliability of limit mechanisms. Especially in complex or confined operating environments, the equipment needs to have flexible adjustment capabilities while ensuring safety. Therefore, there is an urgent need for a lifting device with a more sophisticated structure, featuring a self-locking mechanism, multi-stage limit structure, wire rope force distribution structure, and precisely adjustable beam, to improve the stability, safety, and applicability of lifting operations; and to provide a reliable basis for the dynamic adjustment of crane operating parameters by comprehensively assessing multi-source risks. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art and provide a crane.

[0009] The objective of this invention is achieved as follows: a method for evaluating the safety indicators of a crane, the method comprising: real-time acquisition of crane safety factor data, including the instantaneous rate of change sequence of worm gear speed, prevailing wind angle and instantaneous wind speed, and the actual weight and material type of the hoisted material; calculating the operational stability index based on the instantaneous rate of change sequence of worm gear speed to obtain a mechanical risk factor; determining the lateral wind load state of the crane through the prevailing wind angle and instantaneous wind speed to obtain an environmental risk factor; obtaining the corresponding material strength parameters according to the material type of the material, and calculating the real-time maximum allowable bearing capacity considering the material influence based on the rated load capacity to obtain a load risk factor; dynamically correcting the load risk factor according to the influence of the mechanical risk factor and the environmental risk factor on the load; comparing the corrected load risk factor with a preset safety threshold, and when the corrected load risk factor exceeds the preset safety threshold, dynamically adjusting the crane parameters according to at least one of the mechanical risk, environmental risk, and load risk.

[0010] Furthermore, the instantaneous rate of change sequence of the worm gear speed is obtained, including: continuously collecting discrete data of the instantaneous position change of the worm gear based on a preset time interval; constructing a time correlation based on the discrete data of adjacent sampling points, performing difference analysis on the position change within adjacent time intervals, extracting the motion change characteristics per unit time, and obtaining the intermediate state sequence of the worm gear motion trend; performing difference analysis again on the intermediate time sequence to obtain the instantaneous trend sequence of the worm gear speed change.

[0011] Beneficial effects: The present invention has the following technical effects when used:

[0012] 1. This application couples and quantifies independent safety factors such as machinery, environment, and load to form a comprehensive safety risk index, which fully reflects the instantaneous risks of cranes under actual working conditions. By analyzing the worm gear speed to quantify wear risks, the assessment of safety factors of crane components is upgraded from post-maintenance to pre-warning. It realizes dynamic and adaptive control of environmental wind direction on the safety protection system and locking limit structure, and actively reduces the working range under the threat of cross wind, which greatly enhances the structural stability in complex environments. By introducing a dynamic weight correction mechanism into the calculation of the comprehensive safety risk index, it can adapt to the changes in attention to component wear at different stages of the crane's life cycle, such as the later stages of use, and realize intelligent safety management of cranes.

[0013] 2. The lifting mechanism has a self-locking capability to ensure a safe and reliable lifting process:

[0014] The lifting mechanism of this device uses a worm gear and worm to drive the roller shaft to rotate. Since the worm gear transmission has an irreversible self-locking characteristic, when the power supply to the second drive mechanism stops or an unexpected failure occurs, the worm gear cannot reverse drive the worm, thereby keeping the roller shaft stationary. This effectively prevents the hook and heavy objects from suddenly falling due to the slippage of the wire rope, significantly improving the safety and reliability of the equipment.

[0015] 3. The three-fold reversal wire rope winding method reduces the stress at a single point and improves the load-bearing capacity:

[0016] The wire rope passes through roller one, roller two, and roller three in sequence. Through three folds, the force of the wire rope is distributed to multiple directions and pulley groups. Compared with the single-rope direct hanging structure, this greatly reduces the single-point force and improves the overall lifting structure's load-bearing capacity and service life. At the same time, the cooperation of multiple pulley groups can reduce lifting resistance and make the lifting process more stable.

[0017] 4. The telescopic crossbeam allows for length and angle adjustment, adapting to various hoisting needs:

[0018] The telescopic beam not only extends and retracts in length through its own structure, but also adjusts its horizontal angle through a rotating mechanism with the support frame. A bevel gear at the output of the drive mechanism drives a moving gear, which in turn drives a fixed gear, achieving precise rotation control of the beam. This allows the fixed frame and hook to cover a larger working range, thus enhancing the device's adaptability to heavy objects in different positions and directions.

[0019] 5. The limiting mechanism provides dual limiting and resistance to external forces, ensuring stable positioning of the crossbeam without deviation:

[0020] The limiting mechanism, through the cooperation of the lifting plate, limiting cylinder, limiting wheel, and springs one and two, can automatically form two damping effects—friction limiting and structural limiting—when the telescopic beam stops rotating. When the limiting block moves down, the friction between its bottom and the bottom of the lifting groove increases, preventing the beam from deflecting due to inertia or small external forces. When it moves further down, the limiting wheel is driven to move outward and embed into the limiting groove, achieving mechanical slot limiting. This maintains the stability and angle of the beam even under large external forces, effectively avoiding swaying and misalignment during hoisting and improving operational accuracy.

[0021] 6. The roller assembly effectively reduces wire rope wear and improves lifting smoothness:

[0022] By installing roller two at the bottom of the fixed frame and roller three at the bottom of the outer end, the wire rope always runs along the rolling contact surface during lifting, reducing friction between the wire rope and the fixed frame, decreasing wear, and increasing the lifespan of the wire rope. At the same time, the presence of the rollers reduces the running resistance of the wire rope, requiring less driving force from the lifting mechanism and improving energy efficiency.

[0023] 7. The design of the connecting frame and rollers improves the force stability and directional freedom of the hook:

[0024] The hook and the connecting frame are rotatably connected, and a roller is installed inside the connecting frame to allow the wire rope to roll stably within the frame and maintain a natural change in the direction of force. This structure allows the hook to automatically adjust its angle when lifting heavy objects, avoiding uneven loading, improving the hook's force balance, and enhancing the stability and safety of the lifting process.

[0025] 8. The drive structure is centrally located, the transmission chain is short, and maintenance is simple:

[0026] Drive mechanism one and drive mechanism two are respectively located at the ends of the telescopic beam and the fixed frame, and directly cooperate with the corresponding gears and worm gears. The transmission path is short and the structure is compact, making the maintenance of the overall device more convenient and reducing the wear and loosening problems that are prone to occur in multi-stage transmissions in traditional lifting systems.

[0027] 9. The overall structure has higher safety redundancy and reliability:

[0028] This device, through a combination of "worm gear self-locking, multi-wheel wire rope force distribution, dual-stage limit mechanism, and adjustable beam structure," effectively avoids common risks such as swaying of heavy objects, falling from heights, and accidental beam displacement when lifting heavy objects. It is suitable for various scenarios such as factory equipment handling, construction site hoisting, and lifting of small warehouse goods, significantly improving overall safety and ease of use. Attached Figure Description

[0029] Figure 1 Flowchart of the safety performance evaluation method for the invented crane;

[0030] Figure 2 This is a schematic diagram of the invention.

[0031] Figure 3 This is a partial structural cross-sectional view of the invention.

[0032] Figure 4 A schematic diagram of the hook, roller, and connecting frame structure for the invention.

[0033] Figure 5 This is a schematic diagram of the structure of roller 2, roller 3, and roller shaft of the invention.

[0034] Figure 6 This is a schematic diagram of the worm gear and worm shaft structure of the invention.

[0035] Figure 7 This is a schematic diagram of the connecting rod and sleeve structure of the invention.

[0036] Figure 8 This is a schematic diagram of the limiting mechanism of the invention.

[0037] Figure 9 This is a partial structural diagram of the limiting mechanism of the invention.

[0038] Figure 10 This is a partial structural cross-sectional view of the limiting block of the invention.

[0039] Explanation of reference numerals in the attached figures:

[0040] 1. Support frame, 2. Telescopic crossbeam, 3. Fixed frame, 4. Steel wire rope, 5. Hook, 6. Drive mechanism one, 7. Lifting mechanism, 8. Sleeve, 9. Fixed gear, 10. Moving gear, 11. Drive mechanism two, 12. Bevel gear two, 13. Bevel gear one, 14. Lifting plate, 15. Roller one, 16. Connecting frame, 17. Connecting ear plate, 18. Roller two, 19. Roller three, 20. Roller shaft, 21. Connecting rod, 22. Spring one, 23. Limiting wheel, 24. Limiting block, 25. Limiting groove, 26. Connecting shaft, 27. Spring two, 28. Limiting cylinder, 29. Moving groove, 30. Slider, 31. Slide groove, 32. Spring three, 33. Strip groove, 34. Worm gear, 35. Worm. Detailed Implementation

[0041] Example 1, please refer to Figure 1 The present application provides a method for evaluating the safety indicators of a crane, the specific implementation process of which is as follows:

[0042] Step S1: Collect real-time safety factor data of the crane, including the instantaneous rate of change sequence of worm gear speed, prevailing wind direction angle and instantaneous wind speed, as well as the actual weight and material type of the hoisted material.

[0043] It should be noted that the instantaneous rate of change sequence of the worm gear speed is obtained by acquiring the pulse count sequence within a unit time interval through an encoder installed on the worm gear shaft of the crane's slewing mechanism. After second-order difference processing, the instantaneous rate of change sequence of the worm gear speed is obtained. The instantaneous rate of change sequence of the worm gear speed is used to quantify high-frequency vibrations caused by worm gear tooth surface wear or abnormal meshing, and is a core indicator for measuring the health of components.

[0044] The prevailing wind angle and instantaneous wind speed are obtained in real time by a three-dimensional wind direction sensor at the top of the tower. This information is used to determine the lateral wind load and is the environmental condition that triggers the dynamic adjustment of the limiting structure.

[0045] The actual weight and material type of the hoisted materials are obtained through electronic hook scales and a material information system. This includes information such as the material type (e.g., steel structure, prestressed concrete). The material's material properties determine its impact and vibration resistance, directly affecting the safety factor setting.

[0046] In this embodiment of the application, obtaining the instantaneous rate of change sequence of the worm gear speed includes:

[0047] Discrete data of the instantaneous position change of the worm gear are continuously collected based on a preset time interval;

[0048] Based on discrete data from adjacent sampling points, a temporal correlation is constructed. Difference analysis is performed on the positional changes within adjacent time intervals to extract motion change characteristics per unit time, thus obtaining the intermediate state sequence of the worm gear's motion trend; this can be represented as: ,in For the first The pulse count value collected at the nth time point is the value collected at the nth time point. The angular displacement of the worm gear at each point in time. Indicates the first The pulse count values ​​obtained at each time point. This represents the pulse difference between two adjacent sampling times, i.e., the displacement increment.

[0049] Performing interpolation analysis again on the intermediate time series yields the instantaneous trend sequence of the worm gear speed change, which can be represented as follows: , A sequence representing the instantaneous rate of change of the worm gear speed can capture minute high-frequency vibrations of the worm gear.

[0050] This application uses two-level difference processing to transform discrete sampled data into a dynamic feature sequence that can characterize motion stability. The dynamic feature sequence can characterize the sudden changes, jitter, and nonlinear changes in worm gear speed, and identify the abnormal operating state of the crane's slewing mechanism caused by gear contact impact during transmission. Thus, the instantaneous rate of change sequence of worm gear speed is transformed into the basis for calculating the running stability index.

[0051] Step S2: Calculate the operational stability index based on the instantaneous rate of change sequence of worm gear speed to obtain the mechanical risk factor.

[0052] It should be noted that the calculation of the operational smoothness index primarily aims to quantify abnormal vibrations or impacts generated during worm gear transmission, thereby reflecting the degree of wear on components. This is based on the acquired instantaneous rate of change sequence of the worm gear speed, i.e., the quadratic difference sequence of the speed. This instantaneous rate of change sequence contains all the dynamic information of the worm gear motion, where high-frequency components are typically directly related to impacts and abnormal vibrations caused by poor gear contact, wear, or microcracks.

[0053] In this embodiment of the application, the calculation of the operational stability index includes:

[0054] Perform a Fast Fourier Transform on the instantaneous rate of change sequence to separate and extract the high-frequency vibration components contained in the instantaneous rate of change sequence.

[0055] The average energy of the high-frequency vibration components is calculated, and the average energy is used as the final indicator of operational stability.

[0056] It should be noted that the higher the final operational smoothness index value, the stronger the energy of the worm gear transmission system under high-frequency impact or abnormal vibration, thus indicating more severe wear of transmission components or potential structural abnormalities.

[0057] Step S3: Determine the lateral wind load status of the crane by the prevailing wind angle and instantaneous wind speed, and obtain the environmental risk factor.

[0058] The lateral wind load status of the crane is determined by the prevailing wind angle and instantaneous wind speed. When the crane is under lateral wind load, if the mechanical risk factor is less than a preset threshold but the environmental risk factor is higher than a preset threshold, the trigger threshold of the locking limit structure is dynamically adjusted. This allows the limit structure to be locked in advance or the permissible operating sector to be reduced, thus forming a mandatory safety intervention. The trigger threshold is then sent to the crane control system to control the limit structure.

[0059] It should be noted that crosswind determination: when the angle between the prevailing wind direction and the direction of the boom is within a certain range... Furthermore, when the instantaneous wind speed exceeds a certain threshold, it is judged to be a lateral wind load state.

[0060] In this embodiment, the trigger threshold of the locking limit structure is dynamically adjusted. Specifically, if the lateral wind load state is determined, the allowable range of the slewing limit angle is reduced by a preset angle, or the allowable range of the luffing limit distance is reduced by a preset length. Under the threat of lateral wind, the working geometry of the crane is actively restricted, transforming the environmental threat into an operational constraint and improving the safety of crane operation.

[0061] It should be noted that this application employs an environmental risk-based adaptive shrinkage mechanism for the operating space. When the crane is determined to be in a high-risk state of lateral wind load based on the prevailing wind angle and instantaneous wind speed, a safety downgrade process will be immediately implemented. This safety downgrade process is used to eliminate the overturning risk and lateral bending stress of the structure caused by the lateral wind load. Specifically, it dynamically shrinks the crane's permissible operating boundaries.

[0062] Specifically, for the slewing mechanism, the allowable range of the slewing limit angle is reduced by a preset angle, thereby limiting the operating sector of the crane in the windward or crosswind direction.

[0063] For luffing mechanisms, the allowable range of luffing limit distance is reduced by a preset length, thereby limiting the increase in torque that may result from boom extension under crosswind conditions.

[0064] This application uses an adaptive shrinkage mechanism to create a safer intermediate state, namely a new limit boundary, to ensure that even under strong crosswinds, the crane structure will not reach the original design safety limit.

[0065] Step S4: Obtain the corresponding material strength parameters according to the material type, and calculate the real-time maximum allowable bearing capacity considering the material influence based on the rated load capacity, obtain the load risk factor, and dynamically correct the load risk factor according to the influence of mechanical risk factor and environmental risk factor on the load.

[0066] It should be noted that, for the dynamic verification of the crane's real-time maximum allowable load capacity, this application introduces a derating mechanism based on material fatigue characteristics. The core of the derating mechanism is to ensure that the crane's metal structure can adapt to the damage resistance of its material itself when bearing the load.

[0067] In this embodiment of the application, the corresponding material strength parameters are obtained according to the material type of the material, and the real-time maximum allowable bearing capacity, taking into account the influence of the material, is calculated based on the rated load capacity, including:

[0068] Material strength parameters are obtained from a preset database. These parameters are used to quantify the material’s sensitivity to stress concentration or brittle fracture. The higher the material’s sensitivity, the greater the risk of failure under fatigue accumulation.

[0069] The derating correction calculation is performed, which takes the static rated maximum load capacity as the basis and applies a nonlinear reduction to the static rated maximum load capacity. The reduction amount depends on the product of the material strength parameter and the correction coefficient of the material's influence on the load capacity. This correction coefficient is used to balance the physical weight of material properties in the overall structural load capacity.

[0070] The calculated real-time maximum allowable load-bearing capacity is used to establish a more easily judged intermediate state, reflecting the upper limit of the load that the crane can currently safely withstand, taking into account inherent defects or aging characteristics of the structural materials. This mechanism aims to eliminate the risk of overestimating the load-bearing capacity due to material fatigue or high brittleness.

[0071] In this embodiment of the application, the formula for calculating the real-time maximum allowable bearing capacity can be expressed as: ,in This represents the correction factor. Indicates the material strength parameter. Indicates the rated maximum load capacity. This indicates the maximum allowable bearing capacity in real time.

[0072] In this embodiment of the application, the load risk factor is dynamically corrected based on the impact of mechanical risk factors and environmental risk factors on the load, including:

[0073] The inertial additional force is obtained by measuring the real-time wind speed and the windward area of ​​the suspended object. The inertial additional force is then reduced from the maximum allowable bearing capacity to obtain the first corrected bearing capacity.

[0074] In this embodiment of the application, the formula for calculating the inertial additional force is: ,in air density, For instantaneous wind speed, The windward area of ​​the suspended object. This is the drag coefficient. This is due to inertial additional force. The inertial additional force amplifies the resistance generated by environmental wind on the suspended load, increasing the burden on the crane structure.

[0075] The first corrected bearing capacity, obtained by subtracting the inertial additional force from the maximum allowable bearing capacity, can be expressed as: , As the first correction bearing capacity, environmental risks are directly coupled into the load risk index.

[0076] The additional load caused by mechanical vibration is calculated based on the instantaneous rate of change sequence of worm gear speed. The additional load is then added to the actual weight of the suspended object to obtain the weight of the first suspended object.

[0077] In this embodiment, the peak value is extracted from the instantaneous rate of change sequence of the worm gear speed to obtain the vibration intensity coefficient. The formula for calculating the additional load can then be expressed as: ,in The vibration intensity coefficient, It is the vibration amplification factor. This is the acceleration due to gravity. This refers to the actual weight of the object being lifted. For additional load.

[0078] The additional load is added to the actual weight of the suspended load to obtain the weight of the first suspended load, which can be expressed as: ,in This is the weight of the first load being lifted.

[0079] The ratio of the weight of the first load to the first corrected load capacity is used as the corrected load risk factor. When the corrected load risk factor exceeds the preset safety threshold, it indicates that the crane's lifting task has a high risk and safety intervention is required.

[0080] In this embodiment of the application, the modified load risk factor can be expressed as: When mechanical vibration intensifies due to worm gear wear or improper operation, even if the static material weight remains unchanged, the adjusted load risk factor will automatically increase due to the increased additional load. This application addresses the problem of focusing only on static weight and neglecting the impact of mechanical motion on lifting stability. By deeply coupling mechanical and environmental factors, this application provides a safety protection basis for assessing the safety indicators of cranes.

[0081] It should be noted that when the total load caused by vibration exceeds the preset safe load threshold, this application will automatically trigger speed limiting or stop rotation to prevent fatigue or fracture of the metal structure caused by dynamic load effects.

[0082] Step S5: Compare the modified load risk factor with the preset safety threshold. When the modified load risk factor exceeds the preset safety threshold, dynamically adjust the crane parameters based on at least one of mechanical risk, environmental risk, and load risk.

[0083] It should be noted that when the corrected load risk factor exceeds the preset safety threshold, and when the prevailing wind angle is in a lateral position and the instantaneous wind speed is high, the trigger threshold of the locking limit structure is adjusted. For example, by modifying the angle limit parameter in the controller, the slewing allowable sector is changed from... Dynamically shrink to 12 This allows for the early locking of the limiting structure, forcibly avoiding high-risk operating angles.

[0084] When the mechanical risk factor exceeds a preset threshold, a command is sent to the frequency adjustment unit of the crane controller based on the overall risk level to dynamically reduce the maximum permissible slewing speed and hoisting speed. For example, the operating speed is limited to within 30% of the initial setting to reduce dynamic load impact caused by mechanical wear.

[0085] When the material is stress-sensitive and the weight of the first load exceeds a preset threshold, a mandatory safety intervention is triggered, locking the direction that increases risk and allowing only safe actions that reduce torque to be performed, such as inward amplitude adjustment or load reduction.

[0086] This application allows the crane to operate in a downgraded manner by adjusting parameters such as speed, radius, and limit switches, enabling lifting operations to be performed while ensuring safety. For example, when the risk comes from crosswinds, adjusting the limit switches is the preferred method; when the risk comes from mechanical wear, limiting the speed is the preferred method. Through targeted parameter adjustments, the crane can ensure safe operation under load conditions.

[0087] like Figure 2-10 As shown, the objective of this invention is achieved as follows: A crane includes a base, a support frame 1 is mounted on the base, a telescopic beam 2 is mounted on the support frame 1, the telescopic beam 2 is rotatably connected to the support frame 1, a rotating mechanism is provided between the telescopic beam 2 and the support frame 1, the rotating mechanism drives the telescopic beam 2 to rotate relative to the support frame 1; a fixed frame 3 is fixedly mounted on the outer end of the telescopic beam 2, a lifting mechanism 7 is provided inside the fixed frame 3, a hook 5 is provided at the lower end of the lifting mechanism 7, the lifting mechanism 7 includes a roller 20, the roller 20 is rotatably located inside the fixed frame 3, a steel wire rope 4 is wound on the roller 20, a connecting frame 16 is rotatably mounted on the upper end of the hook 5, a roller 15 is provided inside the connecting frame 16, a connecting ear plate 17 is provided in the middle of the upper end of the connecting frame 16, a roller 28 is rotatably mounted on the lower part of the fixed frame 3, the steel wire rope 4 passes under the roller 15, passes over the roller 28, and then connects to the connecting ear plate 17.

[0088] A roller 19 is rotatably mounted on the lower outer end of the fixed frame 3, and a steel wire rope 4 passes through the left side of the roller 19. The outer end of the central shaft of the roller 20 rotatably passes through the fixed frame 3, and a worm gear 34 is fixedly connected to the outer end of the central shaft of the roller 20. A drive mechanism 11 is mounted on the fixed frame 3, and a worm 35 is mounted on the output end of the drive mechanism 11. The worm gear 34 and the worm 35 mesh with each other for transmission.

[0089] The rotating mechanism includes a connecting shaft 26, which is fixedly connected to the upper end of the support frame 1 and rotatably connected to the middle of the left end of the telescopic beam 2. A fixed gear 9 is fixedly installed at the lower part of the connecting shaft 26, and a movable gear 10 is rotatably installed inside the left end of the telescopic beam 2. The movable gear 10 meshes with the fixed gear 9. The rotation of the movable gear 10 drives the telescopic beam 2 to rotate. A bevel gear 12 is fixedly installed on the upper surface of the movable gear 10. A drive mechanism 6 is fixedly installed at the left end of the telescopic beam 2. A bevel gear 13 is installed at the output end of the drive mechanism 6. The bevel gear 13 meshes with the bevel gear 12. The drive mechanism 6 drives the telescopic beam 2 to rotate relative to the center of the support frame 1.

[0090] A limiting mechanism is provided between the telescopic beam 2 and the support frame 1. The limiting mechanism includes a connecting rod 21 and a sleeve 8. The sleeve 8 is fixed to the telescopic beam 2. A limiting block 24 is provided on the connecting rod 21 and can move up and down. A lifting groove is provided on the telescopic beam 2 and is located below the sleeve 8. The limiting block 24 is located in the lifting groove and can move up and down. The lower right end of the lifting plate 14 has a cylindrical structure and can move up and down within the sleeve 8. The bottom of the limiting block 24 and the bottom of the lifting groove are both friction surfaces. A lifting plate 14 is provided on the upper end of the limiting block 24. The lifting plate 14 drives the limiting block 24 to move up and down. The connecting rod 21 can move up and down through the lifting plate 14. A lifting mechanism 7 is provided on the telescopic beam 2 and drives the lifting plate 14 to move up and down.

[0091] Multiple limiting grooves 25 are evenly provided on the side of the lifting groove. A spring 22 is provided between the limiting block 24 and the lifting plate 14. Multiple moving grooves 29 are evenly distributed inside the limiting block 24. A limiting wheel 23 is provided inside the moving groove 29. A central shaft is rotatably provided in the middle of the limiting wheel 23. A slider 30 is provided on both the front and rear sides of the central shaft. A sliding groove 31 is provided on both the front and rear sides of the moving groove 29. The slider 30 is located in the sliding groove 31 and can move left and right. A spring 32 is provided on the right side of the slider 30. The left and right ends of the spring 32 are connected to the slider 30 and the sliding groove 31, respectively. Strip grooves 33 are provided on the left and right sides of the moving groove 29. The limiting wheel 23 can pass through the strip groove 33 on both the left and right sides.

[0092] A limiting cylinder 28 is provided in the middle of the limiting block 24, which can move up and down. The outer side of the limiting cylinder 28 is an arc-shaped structure that tapers downward. The connecting rod 21 can move up and down through the middle of the limiting cylinder 28. A spring 27 is provided between the limiting cylinder 28 and the lifting plate 14.

[0093] In use, the lifting mechanism 7 moves the hook 5 up and down, the telescopic beam 2 adjusts the length of the fixed frame 3, the rotating mechanism rotates the telescopic beam 2, the hook 5 is hung on the heavy object to be lifted, and the lifting mechanism 7 lifts the heavy object. The lifting mechanism 7 is equipped with a worm gear 34 and a worm 35 to achieve self-locking of the roller shaft 20. When the drive mechanism 11 loses power, the worm gear 34 and worm 35 can self-lock it, thus preventing the wire rope 4 from falling and causing a safety accident.

[0094] The worm gear 34 is fixedly connected to the outer end of the central shaft of the roller 20, so that the self-locking action is directly applied to the winding part of the wire rope 4, thereby improving the locking accuracy. The worm 35 is installed on the side wall of the fixed frame 3, so that the meshing center distance is constant. Even when the crossbeam rotates or the load changes, it still maintains stable meshing and will not reduce the self-locking force due to structural deformation, thereby further improving the safety and reliability of the lifting process.

[0095] The steel wire rope 4 is folded three times to lift heavy objects, which avoids the stress on a single steel wire rope 4 and facilitates the lifting of the steel wire rope 4. Roller 15 is located inside the connecting frame 16, roller 2 18 is located at the lower part of the fixed frame 3, and roller 3 19 is located at the lower part of the outer end of the fixed frame 3. The three sets of rollers form an "S-shaped" guide path, which can effectively reduce the bending angle of the steel wire rope 4, improve the smoothness of the steel wire rope 4's operation, and reduce local wear; at the same time, the steel wire rope 4 maintains rolling contact with the rollers, making the lifting process less resistant and the lifting efficiency higher. A limit mechanism is set to limit the telescopic beam 2. That is, when the drive mechanism 1 6 is not working, the control lifting mechanism 7 drives the lifting plate 14 to move downward, which in turn drives the limit block 24 to move downward. At this time, the spring 22 is compressed, and the squeezing force between the bottom of the limit block 24 and the bottom of the lifting groove increases, thereby increasing the friction between the two, making the telescopic beam 2 less likely to rotate under the action of external force. The lifting trough is a longitudinal trough structure, which makes the limiting block 24 form a stable guide with the trough wall, improves the consistency of the direction of the limiting force, and thus strengthens the anti-rotation ability of the telescopic beam 2 under high load or lateral external force.

[0096] The lifting plate 14 is moved downwards again, causing the limiting cylinder 28 to move downwards, which in turn causes the second spring 27 to be compressed. The outer side of the lower part of the limiting cylinder 28 first comes into contact with the inner side of the limiting wheel 23, causing the limiting wheel 23 to move outwards. The slider 30 moves outwards, which in turn causes the third spring 32 to be compressed. The outer side of the limiting wheel 23 comes into contact with the outer side of the lifting groove. When the telescopic beam 2 rotates, the limiting wheel 23 is located in the limiting groove 25, and under the compression of the second spring 27, it causes the limiting cylinder 28 to continue to move downwards, so that the limiting wheel 23 enters the limiting groove 25. Due to the limiting effect between the limiting wheel 23 and the limiting groove 25, the telescopic beam 2 cannot rotate, thus achieving the limiting and fixing of the telescopic beam 2 and the support frame 1.

[0097] When it is necessary to rotate the telescopic beam 2, the control lifting mechanism 7 is reset, the limit wheel 23 is reset under the elastic force of the spring 32, the limit wheel 23 is disengaged from the limit groove 25, and the limit cylinder 28 is not in contact with the bottom of the lifting cylinder; thus, the telescopic beam 2 can be rotated.

[0098] It should be noted that the specific structural layout, connection form, and number of components in the lifting device described in this application are preferred embodiments and are not intended to limit the scope of protection of this invention. For example, the matching relationship between the fixed gear, moving gear, bevel gear, and connecting shaft used in the rotating mechanism can be replaced by other structures that can achieve beam rotation, such as sprocket and chain drive, swing connection assembly, or other angle adjustment mechanisms; the method of using worm gear to self-lock the roller shaft in the lifting mechanism can also be replaced by a reducer with a self-locking structure, ratchet and pawl mechanism, or electromagnetic braking mechanism, etc., which can achieve an equivalent self-locking effect; the rollers one, roller two, and roller three used in the wire rope winding path can also have their number and distribution position adjusted according to usage requirements, or a pulley block structure can be used to achieve the same guiding and force-sharing effect; the combination relationship of the limiting groove, limiting wheel, limiting cylinder, and various springs in the limiting mechanism can also be replaced by other structures with friction limiting or mechanical locking functions. Therefore, as long as it does not deviate from the functional purpose and technical effect achieved by the technical solution of this application, it should fall within the protection scope of this invention.

[0099] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0100] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. 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 method for evaluating the safety indicators of a crane, characterized in that, include: Real-time acquisition of crane safety factor data, including the instantaneous change rate sequence of worm gear speed, prevailing wind direction angle and instantaneous wind speed, as well as the actual weight and material type of the hoisted materials; The operational stability index is calculated based on the instantaneous rate of change sequence of worm gear speed to obtain mechanical risk factors; The lateral wind load status of the crane is determined by the prevailing wind angle and instantaneous wind speed, and environmental risk factors are obtained. Obtain the corresponding material strength parameters based on the material type, and calculate the real-time maximum allowable bearing capacity considering the material influence based on the rated load capacity. Obtain the load risk factor, and dynamically correct the load risk factor based on the influence of mechanical risk factor and environmental risk factor on the load. The modified load risk factor is compared with the preset safety threshold. When the modified load risk factor exceeds the preset safety threshold, the crane parameters are dynamically adjusted based on at least one of mechanical risk, environmental risk, and load risk.

2. The crane safety index evaluation method according to claim 1, characterized in that, Obtain the instantaneous rate of change sequence of the worm gear speed, including: Discrete data of the instantaneous position change of the worm gear are continuously collected based on a preset time interval; Based on the discrete data of adjacent sampling points, a time correlation relationship is constructed, and the position change within adjacent time intervals is analyzed by difference to extract the motion change characteristics per unit time and obtain the intermediate state sequence of the worm gear motion trend. Perform interpolation analysis again on the intermediate time series to obtain the instantaneous trend sequence of worm gear speed changes.

3. The crane safety index evaluation method according to claim 1, characterized in that, The calculation of operational stability indicators includes: Perform a Fast Fourier Transform on the instantaneous rate of change sequence to separate and extract the high-frequency vibration components contained in the instantaneous rate of change sequence. The average energy of the high-frequency vibration components is calculated, and the average energy is used as the final indicator of operational stability.

4. The crane safety index evaluation method according to claim 1, characterized in that, The data for hoisting materials includes: obtaining the corresponding material strength parameters based on the material type, and calculating the real-time maximum allowable load-bearing capacity considering the influence of the material based on the rated load capacity, including: Retrieve material strength parameters from the preset database; A derating correction calculation is performed on the material strength parameters, taking the static rated maximum load capacity as the basis, and applying a nonlinear reduction process to the static rated maximum load capacity. The real-time maximum allowable bearing capacity is obtained by multiplying the rated maximum bearing capacity by the nonlinear reduction process.

5. The crane safety index evaluation method according to claim 1, characterized in that, The formula for calculating the real-time maximum allowable bearing capacity considering the influence of material can be expressed as: ,in This represents the correction factor. Indicates the material strength parameter. Indicates the rated maximum load capacity. This indicates the maximum allowable bearing capacity in real time.

6. The method for evaluating crane safety indicators according to claim 1, characterized in that, The operational stability index is calculated based on the instantaneous rate of change sequence of worm gear speed to obtain mechanical risk factors; The lateral wind load state of the crane is determined by the prevailing wind angle and instantaneous wind speed, and environmental risk factors are obtained, including: When the mechanical risk factor is less than the preset threshold and the environmental risk factor is higher than the preset threshold, the trigger threshold of the locking limit structure is dynamically adjusted to enable the limit structure to lock in advance or reduce the permissible operating sector, thus forming a mandatory safety intervention.

7. The method for evaluating crane safety indicators according to claim 1, characterized in that, Based on the impact of mechanical and environmental risk factors on the load, the load risk factor is dynamically adjusted, including: The inertial additional force is obtained by measuring the real-time wind speed and the windward area of ​​the suspended object. The inertial additional force is then reduced from the maximum allowable bearing capacity to obtain the first corrected bearing capacity. The additional load caused by mechanical vibration is calculated based on the instantaneous rate of change sequence of worm gear speed. The additional load is then added to the actual weight of the suspended object to obtain the weight of the first suspended object. The ratio of the weight of the first load to the first modified load capacity is used as the modified load risk factor.

8. A crane, characterized in that, The device includes a base with a support frame mounted on it. The support frame has a telescopic beam, which is rotatably connected to the support frame. A rotating mechanism connects the telescopic beam and the support frame, causing the telescopic beam to rotate relative to the support frame. A fixed frame is fixedly mounted on the outer end of the telescopic beam, and a lifting mechanism is installed within the fixed frame. A hook is located at the lower end of the lifting mechanism. The lifting mechanism includes a roller, which is rotatably located within the fixed frame. A steel wire rope is wound around the roller. A connecting frame is rotatably mounted on the upper end of the hook, and a first roller is installed within the connecting frame. A connecting ear plate is located in the middle of the upper end of the connecting frame. A second roller is rotatably mounted on the lower part of the fixed frame. The steel wire rope passes under the first roller, then over the second roller, and finally connects to the connecting ear plate.

9. The crane according to claim 8, characterized in that, The lower outer end of the fixed frame is rotatably equipped with roller three, and the steel wire rope passes through the left side of roller three.

10. The crane according to claim 8, characterized in that, The roller shaft has a rotatable through-fixed frame at its outer end. A worm gear is fixedly connected to the outer end of the roller shaft. A second drive mechanism is provided on the fixed frame. A worm is provided at the output end of the second drive mechanism. The worm gear and the worm mesh with each other for transmission.

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