Overload protection device and protection method for cable-crossing crane

Abstract

The invention belongs to the technical field of bridge construction, and particularly relates to an overload protection device and method for a cable-crossing crane, the overload protection device comprises a frame main body, and further comprises a load sensor and a control system, a walking beam is slidably clamped to the outer surface of a guide rail of the frame main body, and an audible and visual alarm is fixedly connected to the upper surface of the walking beam; connecting beams are fixedly connected to the surfaces of the opposite sides of the two walking beams, steel cable rollers are arranged above the connecting beams, hoisting steel cables are wound on the outer surfaces of the steel cable rollers, hoisting adjusting mechanisms are arranged on the outer surfaces of the connecting beams, and braking mechanisms are further arranged on the outer surfaces of the connecting beams. According to the overload protection device and method for the cable-crossing crane, the hoisting clamp is lowered at the speed adjusted through an algorithm, meanwhile, the adjusting screw rod is driven to rotate, then the threaded pipe sleeve is controlled to horizontally move on the outer surface of the threaded pipe sleeve, and horizontal adjustment of the movable beam pipe and the steel cable roller is achieved under connection of the linkage rod and the supporting base; therefore, the hoisting angle of the hoisting steel rope can be changed, and the load distribution of the hurdle crane can be effectively changed.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge construction, and in particular, to an overload protection device and a protection method for a cross-cable crane. Background Art

[0002] At present, the commonly used methods for hoisting the stiffening girder of a conventional suspension bridge include the cable crane method, the cross-cable crane method, the floating crane hoisting method, and the cable-rail hoisting method. The cross-cable crane is a suspension bridge construction equipment used to lift the stiffening girder segment from the bridge bottom to the designed position. It has the advantages of being not limited by the bridge span and height and having a large lifting capacity, and is an essential equipment for the construction of long-span suspension bridges. The known cross-cable crane structure consists of a cross beam, a hinge support, and a lifting device. The self-propelled cross-cable crane also includes a traveling device.

[0003] In the traditional cross-cable crane system, the weight of the lifted object is often unstable. Therefore, overload is a major problem affecting the safety of the crane. If the crane is overloaded, it will not only cause components such as the crane motor and the electric control system to overheat or be damaged, but also may cause deformation or even collapse of the crane structure, thus bringing great risks to the operator and the equipment. In order to prevent the crane from being in danger due to overload, an overload protection device is usually used in the industry for safety protection;

[0004] In the prior art, although the overload protection device of the cross-cable crane plays a good protective role, there are still some deficiencies. For example, some traditional overload protection devices only take emergency braking or shutdown measures after overload occurs, lacking a warning mechanism. The operator usually can only know that the load exceeds the standard by relying on the alarm signal or the limit switch, and the reaction time may not be fast enough. When the load is approaching overload, if the operator can be reminded in time to make appropriate adjustments or reduce the load, the safety of the crane operation will be greatly improved. At the same time, although modern overload protection systems already have some intelligent functions, many current systems still lack in-depth data analysis and automatic optimization functions. For example, when the crane load is close to the safety critical value, the overload protection system can provide a more accurate warning through data analysis and machine learning algorithms, and even automatically adjust the operating parameters of the crane according to the working state to avoid overload. Therefore, the present invention solves the deficiencies of the above technical problems. Summary of the Invention

[0005] Based on the above existing technical problems, the present invention proposes an overload protection device and a protection method for a cross-cable crane.

[0006] An overload protection device for a cross-cable crane proposed by the present invention includes a frame body, and also includes a load sensor and a control system. A traveling beam is slidably clamped on the outer surface of the guide rail of the frame body. An audible and visual alarm is fixedly connected to the upper surface of the traveling beam. A connecting beam is fixedly connected to the opposite side surfaces of the two traveling beams. A steel cable roller is arranged above the connecting beam. A hoisting steel cable is wound around the outer surface of the steel cable roller. A hoisting adjustment mechanism is arranged on the outer surface of the connecting beam, and a braking mechanism is also arranged.

[0007] Among them, the control system adopts a PID control algorithm to dynamically adjust the lifting speed of the crane according to the real-time load error to avoid overloading.

[0008] Among them, the hoisting adjustment mechanism moves horizontally and adjusts the hoisting angle of the hoisting steel cable.

[0009] Among them, the braking mechanism locks the hoisting adjustment mechanism after movement.

[0010] Preferably, the formula of the PID control algorithm is:

[0011] [Output=K_p·e(t)+K_i·∫e(t)dt+K_d·\frac{de(t)}{dt}] where e(t) is the load error, which is the product of the difference between the target load and the actual load. The load error measures the gap between the current crane load and the set target load. This error value is used by the control system to adjust the behavior of the crane according to the change of the actual load.

[0012] Among them, [K_p·e(t)] is the proportional control term, K_p is the proportional gain, which controls the direct response of the error.

[0013] Among them, [K_i·∫e(t)dt] is the integral control term, K_i is the integral gain, which controls the accumulation of the error over time.

[0014] [K_d·\frac{de(t)}{dt}] is the derivative control term, K_d is the derivative gain, which controls the rate of change of the error.

[0015] Through the above technical solutions, the proportional control term is directly proportional to the current load error. If the load error is large, the proportional term will generate a large output, thereby adjusting the speed or direction of the crane to correct the load deviation. The role of the integral term is to eliminate small errors that exist for a long time. If there are small errors in the system for a long time, the integral term will continuously accumulate these errors, thereby prompting the system to make corresponding adjustments to prevent the long-term deviation of the system error from the target. The derivative term predicts future errors by detecting the rate of change of the error and takes measures in advance to reduce overshoot or system oscillation.

[0016] Preferably, on the opposite side surfaces of the middle parts of the two connecting beams, an installation beam is fixedly connected. On the upper surface of the installation beam, a reduction gearbox is fixedly connected, and a reduction motor is drivingly connected to the outer surface of the reduction gearbox.

[0017] Through the above technical solution, in order to control the winding and unwinding of the cable roller, a transmission gear set is arranged in the reduction gearbox. Thus, driven by the transmission gear set by the reduction motor, the rotation of the cable roller can be realized, and the transmission gear set makes the rotation of the cable roller have a self-locking effect, making the adjustment of the lifting speed of the crane accurate.

[0018] Preferably, the hoisting adjustment mechanism includes a moving beam tube slidably sleeved on the outer surface of the connecting beam. On the outer surface of the moving beam tube, a radial guide wheel and an axial guide wheel are installed. Below the connecting beam, a hoisting clamp is provided. Four load sensors are symmetrically distributed and fixedly installed on the upper surface of the hoisting clamp. On the upper surface of the housing of the load sensor, a hoisting roller is fixedly installed. On one side surface of the connecting beam, a fixed connector is fixedly installed. The hoisting cable passes through the hoisting roller after being guided by the radial guide wheel and the axial guide wheel, and is connected to the surface of the fixed connector.

[0019] Through the above technical solution, in order to improve the reliability of the hoisting of the hurdle crane, hoisting is achieved by using four symmetric hoisting cables on the upper surface of the hoisting clamp, and the hoisting cables are tensioned and guided through the axial guide wheel and the radial guide wheel to improve the stability of the system hoisting. In order to accurately monitor the load of the hoisting clamp and avoid overload, a multiple redundancy design can be adopted, that is, multiple load sensors are used to detect the load of each hoisting cable to ensure that the load change can be accurately detected and false alarms are prevented.

[0020] Preferably, the hoisting adjustment mechanism further includes a rotating shaft drivingly connected to the reduction gearbox. The cable roller is movably sleeved on the outer surface of the rotating shaft. Connecting grooves are symmetrically formed in the inner wall of the cable roller. A connecting block is fixedly connected to the outer surface of the rotating shaft, and the outer surface of the connecting block is slidably clamped with the inner wall of the connecting groove.

[0021] Through the above technical solution, the load sensor is installed at the connection between the hoisting steel cable and the hoisting fixture. Its function is to monitor the load of the crane in real time and transmit the data to the control system. The control system receives the data from the load sensor and determines whether it is overloaded through the PID control algorithm. According to the real-time load error, it dynamically adjusts the lifting speed of the crane to avoid overloading. The system will preset a safe load value. If the load exceeds the predetermined range, the control system will activate the overload protection mechanism, that is, the audible and visual alarm will sound immediately to remind the operator to pay attention to safety. At the same time, the hoisting fixture will be lowered according to the speed adjusted by the algorithm. In order to improve the safety of lowering the hoisting fixture, the position of the cable roller on the rotating shaft is changed, that is, the cable roller is horizontally moved, so that the hoisting angle of the hoisting steel cable can be changed. By adjusting the angle of the hoisting steel cable, the load distribution of the hurdle crane can be effectively changed, making it disperse the load, thus reducing the burden. In order to realize the rotation of the cable roller at the same time, through the cooperation of the connecting block and the connecting groove, the rotation of the cable roller is realized when the rotating shaft rotates.

[0022] Preferably, the hoisting adjustment mechanism further includes two linkage rods fixedly connected to the opposite side surfaces of the two moving beam pipes. The upper surfaces of the two linkage rods are fixedly connected with support seats with limit rings. The outer surface of the cable roller is fixedly sleeved with a limit ring block. A limit groove is opened on the inner wall of the limit ring of the support seat, and the outer surface of the limit ring block is rotatably sleeved with the inner wall of the limit groove.

[0023] Through the above technical solution, the hoisting steel cable on the cable roller is wound around the outer surfaces of the radial guide wheel and the axial guide wheel on the moving beam pipe. Therefore, when adjusting the hoisting angle of the hoisting steel cable, it is necessary to ensure that the moving beam pipe and the cable roller move synchronously. Then, through the cooperation of the limit ring block and the limit groove, the cable roller rotates on the surface of the support seat. Furthermore, when the moving beam pipe moves on the outer surface of the connecting beam, the synchronous movement of the cable roller can be realized through the connection of the linkage rod.

[0024] Preferably, symmetrically distributed threaded pipe sleeves are fixedly connected to the surfaces of the two linkage rods. One side surface of the walking beam is rotatably connected with adjusting screws through bearings and symmetrically distributed. The inner surface of the threaded pipe sleeve is threadedly sleeved with the outer surface of the adjusting screw. One end outer surfaces of the two adjusting screws are drivingly connected with a pulley assembly. The outer surface of one of the adjusting screws is drivingly connected with a driving gear set. A driving motor is installed on the surface of the walking beam, and the driving motor drives one of the adjusting screws to rotate through the driving gear set.

[0025] Through the above technical solution, in order to achieve the horizontal movement adjustment of the moving beam pipe and the cable roller, the two groups of adjusting screws on both sides of the reduction gearbox rotate synchronously or rotate separately according to an algorithm, so that the control threaded pipe sleeve moves horizontally on its outer surface, and then the horizontal adjustment of the moving beam pipe and the cable roller is realized under the connection of the linkage rod and the support seat. In order to drive the synchronous rotation of the two adjusting screws on one side to achieve the stable movement of the two moving beam pipes on one side, the driving motor drives one of the adjusting screws to rotate through the driving gear set, and then the synchronous rotation of the two adjusting screws is realized under the connection of the pulley assembly, thereby realizing the adjustment of the hoisting angle.

[0026] Preferably, the braking mechanism includes an adjusting block fixedly connected to the upper surface of one end of the moving beam pipe. A movable groove is formed through one side surface of the adjusting block, and a braking roller is slidably connected to the inner wall of the movable groove. Braking grooves are formed on the upper surfaces of both ends of the connecting beam, and the outer surface of the braking roller is slidably clamped with the inner wall of the braking groove.

[0027] Through the above technical solution, the moving beam pipe needs to slide on the outer surface of the connecting beam. In order to prevent the adjusted moving beam pipe from sliding and causing unstable hoisting, after the moving beam pipe is adjusted on the outer surface of the connecting beam, the braking roller in the movable groove is pressed into the braking groove, so that the moving beam pipe can be connected to the connecting beam, avoiding the further movement of the moving beam pipe.

[0028] Preferably, the braking mechanism further includes a T-shaped mounting rod fixedly connected to the upper surface of the adjusting block. Hydraulic rods are fixedly connected to both ends of the mounting rod, the lower surface of the telescopic end of the hydraulic rod is fixedly connected to the upper surface of the braking roller, and a buffer spring is fixedly sleeved on the outer surface of the telescopic end of the hydraulic rod.

[0029] Through the above technical solution, in order to unlock the braking between the moving beam pipe and the connecting beam and achieve the horizontal movement adjustment of the moving beam pipe, when the adjusting screw rotates, the telescopic end of the hydraulic rod contracts, so that the braking roller pressed into the braking groove is lifted upward to disengage from the connection with the connecting beam, thereby realizing the movement of the moving beam pipe. At the same time, during braking, the braking roller is pressed into the braking groove by the hydraulic rod, and the tight connection between the two is achieved through the extrusion of the buffer spring.

[0030] A protection method for an overload protection device of a cross-cable crane proposed by the present invention includes the following steps:

[0031] S1. During the operation of the cross-cable crane, the load sensor continuously monitors the weight of the suspended load. Through real-time data acquisition and transmission, the control system can obtain the current load of the hoisting cable at any time.

[0032] S2. The control system will preset a safety load threshold according to the designed load capacity of the crane. This value takes into account the maximum load-bearing capacity of the crane, working conditions, and safety factor. When the load of the cross-cable crane reaches the preset safety threshold, the control system will immediately issue an overload warning and trigger an audible and visual alarm to remind the operator.

[0033] S3. If the load continues to be overloaded, the control system will automatically take protective measures. That is, the reduction motor drives the rotating shaft to reverse through the reduction gearbox, and then through the cooperation of the connecting block and the connecting groove, when the rotating shaft rotates, the steel cable roller is reversely rotated, so as to unwind the hoisting steel cable under the guidance of the radial guide wheel and the axial guide wheel, making the hoisting fixture slowly descend to reduce its load.

[0034] S4. While the steel cable roller rotates and adjusts, the telescopic end of the hydraulic rod contracts, lifting the brake roller pressed into the brake groove upward to disengage from the connection with the connecting beam, thus realizing the movement of the moving beam tube.

[0035] S5. After the moving beam tube moves, the drive motor drives one of the adjusting screws to rotate through the drive gear set, and then through the connection of the pulley assembly, the two adjusting screws rotate synchronously, controlling the horizontal movement of the threaded tube sleeve on its outer surface. Furthermore, under the connection of the linkage rod and the support seat, the horizontal adjustment of the moving beam tube and the steel cable roller is realized, thereby changing the hoisting angle of the hoisting steel cable. By adjusting the angle of the hoisting steel cable, the load distribution of the crossbar crane is effectively changed, dispersing the load and thus reducing the burden.

[0036] S6. After the moving beam tube finishes moving, the brake roller is pressed into the brake groove by the hydraulic rod, and through the extrusion of the buffer spring, the tight connection between the connecting beam and the moving beam tube is realized, avoiding the sliding of the adjusted moving beam tube and resulting in unstable hoisting. When the hoisting fixture descends to the threshold range, the load on its upper surface is timely unloaded, and hoisting is carried out again.

[0037] The beneficial effects of the present invention are as follows:

[0038] 1. By setting the PID control algorithm, the lifting speed of the crane can be dynamically adjusted according to the real-time load error to avoid overloading. During the adjustment process, according to the error between the real-time data provided by the load sensor and the set target load value, the PID controller will adjust the load according to proportion, integral, and differential. If the load is close to overloading, the PID controller will reduce the lifting speed of the crane or start other protective measures.

[0039] 2. By setting up a hoisting adjustment mechanism, the hoisting angle of the hoisting steel cable can be adjusted. During the adjustment process, the hoisting fixture is lowered at a speed adjusted by an algorithm. Meanwhile, the driving motor drives one of the adjustment screws to rotate through a driving gear set, and then the two adjustment screws rotate synchronously under the connection of the pulley assembly, thereby controlling the horizontal movement of the threaded pipe sleeve on its outer surface. Furthermore, under the connection of the linkage rod and the support seat, the horizontal adjustment of the moving beam pipe and the steel cable roller is achieved. Therefore, the hoisting angle of the hoisting steel cable can be changed. By adjusting the angle of the hoisting steel cable, the load distribution of the cable crane can be effectively changed, so that the load is dispersed, thus reducing the burden.

[0040] 3. By setting up a braking mechanism, the position of the hoisting adjustment mechanism can be fixed. During the adjustment process, the braking roller is pressed into the braking groove by a hydraulic rod, and the tight connection between the two is achieved through the extrusion of the buffer spring, thereby preventing the sliding of the adjusted moving beam pipe and causing unstable hoisting. Description of the Drawings

[0041] Figure 1 Schematic diagram of an overload protection device and protection method for a cable crane proposed by the present invention;

[0042] Figure 2 Three-dimensional structure diagram of the hoisting fixture of an overload protection device and protection method for a cable crane proposed by the present invention;

[0043] Figure 3 Three-dimensional structure diagram of the hoisting steel cable of an overload protection device and protection method for a cable crane proposed by the present invention;

[0044] Figure 4 Three-dimensional structure diagram of the load sensor of an overload protection device and protection method for a cable crane proposed by the present invention;

[0045] Figure 5 Three-dimensional structure diagram of the connecting beam of an overload protection device and protection method for a cable crane proposed by the present invention;

[0046] Figure 6 Three-dimensional structure diagram of the rotating shaft of an overload protection device and protection method for a cable crane proposed by the present invention;

[0047] Figure 7 Three-dimensional structure diagram of the moving beam pipe of an overload protection device and protection method for a cable crane proposed by the present invention;

[0048] Figure 8 Three-dimensional structure diagram of the support seat of an overload protection device and protection method for a cable crane proposed by the present invention;

[0049] Figure 9Stereoscopic view of the adjustment block structure of an overload protection device and protection method for a cross-cable crane proposed by the present invention;

[0050] Figure 10 Stereoscopic view of the brake roller structure of an overload protection device and protection method for a cross-cable crane proposed by the present invention;

[0051] Figure 11 System architecture diagram of the PID control algorithm of an overload protection device and protection method for a cross-cable crane proposed by the present invention.

[0052] In the figure: 1. Frame main body; 2. Load sensor; 3. Traveling beam; 31. Acousto-optic alarm; 4. Connecting beam; 41. Installation beam; 42. Reduction gearbox; 43. Reduction motor; 5. Cable roller; 51. Hoisting cable; 52. Connecting groove; 6. Hoisting adjustment mechanism; 61. Moving beam tube; 62. Radial guide wheel; 63. Axial guide wheel; 64. Hoisting fixture; 65. Hoisting roller; 66. Fixed connector; 67. Rotating shaft; 68. Connecting block; 69. Linkage rod; 70. Support seat; 71. Limit ring block; 72. Limit groove; 73. Threaded pipe sleeve; 74. Adjusting screw; 75. Pulley assembly; 76. Driving gear set; 77. Driving motor; 8. Braking mechanism; 81. Adjusting block; 82. Activity groove; 83. Brake roller; 84. Braking groove; 85. Installation rod; 86. Hydraulic rod; 87. Buffer spring. Specific implementation manners

[0053] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0054] Refer to Figures 1-11 , an overload protection device for a cross-cable crane, including a frame main body 1, further including a load sensor 2 and a control system. A traveling beam 3 is slidably clamped on the outer surface of the guide rail of the frame main body 1. An acousto-optic alarm 31 is fixedly connected to the upper surface of the traveling beam 3. A connecting beam 4 is fixedly connected to the opposite side surfaces of the two traveling beams 3. A cable roller 5 is arranged above the connecting beam 4. A hoisting cable 51 is wound around the outer surface of the cable roller 5. A hoisting adjustment mechanism 6 is arranged on the outer surface of the connecting beam 4, and a braking mechanism 8 is also arranged.

[0055] In order to control the rewinding and unwinding of the cable roller 5, mounting beams 41 are fixedly connected to the opposite surfaces of the middles of the two connecting beams 4. A reduction gearbox 42 is fixedly connected to the upper surface of the mounting beam 41. A reduction motor 43 is drivingly connected to the outer surface of the reduction gearbox 42. A transmission gear set is arranged inside the reduction gearbox 42. Thus, through the drive of the transmission gear set by the reduction motor 43, the rotation of the cable roller 5 can be realized, and the transmission gear set enables the rotation of the cable roller 5 to have a self-locking effect, making the adjustment of the hoisting speed of the crane accurate.

[0056] Among them, the control system adopts the PID control algorithm, and dynamically adjusts the hoisting speed of the crane according to the real-time load error to avoid overloading.

[0057] The formula of the PID control algorithm is:

[0058] [\text{Output}=K_p\cdote(t)+K_i\inte(t),dt+K_d\cdot\frac{de(t)}{dt}] Among them, e(t) is the load error, which is the product of the difference between the target load and the actual load. The load error measures the gap between the current crane load and the set target load. This error value is used by the control system to adjust the behavior of the crane according to the change of the actual load.

[0059] Among them, [K_p\cdote(t)] is the proportional control term, and K_p is the proportional gain, which controls the direct response of the error.

[0060] Among them, [K_i\inte(t),dt] is the integral control term, and K_i is the integral gain, which controls the accumulation of the error over time.

[0061] [K_d\cdot\frac{de(t)}{dt}] is the derivative control term, and K_d is the derivative gain, which controls the rate of change of the error. The proportional control term is directly proportional to the current load error. If the load error is large, the proportional term will generate a large output, thereby adjusting the speed or direction of the crane to correct the load deviation. The role of the integral term is to eliminate small errors that exist for a long time. If there are small errors in the system for a long time, the integral term will continuously accumulate these errors, thereby prompting the system to make corresponding adjustments to prevent the long-term deviation of the system error from the target. The derivative term predicts future errors by detecting the rate of change of the error and takes measures in advance to reduce overshoot or system oscillation.

[0062] By setting the PID control algorithm, the hoisting speed of the crane can be dynamically adjusted according to the real-time load error to avoid overloading. During the adjustment process, according to the error between the real-time data provided by the load sensor 2 and the set target load value, the PID controller will adjust the load according to proportional, integral, and differential. If the load is close to overloading, the PID controller will reduce the hoisting speed of the crane or activate other protection measures.

[0063] Among them, the hoisting adjustment mechanism 6 moves horizontally and adjusts the hoisting angle of the hoisting steel cable 51.

[0064] In order to improve the reliability of the hoisting of the hurdle crane, the hoisting adjustment mechanism 6 includes a moving beam tube 61 slidably sleeved on the outer surface of the connecting beam 4. Radial guide wheels 62 and axial guide wheels 63 are installed on the outer surface of the moving beam tube 61. A hoisting clamp 64 is arranged below the connecting beam 4. Hoisting is realized by using four symmetric hoisting steel cables 51 on the upper surface of the hoisting clamp 64. And the hoisting steel cables 51 are tensioned and guided and adjusted through the axial guide wheels 63 and the radial guide wheels 62 to improve the stability of the system hoisting. In order to accurately monitor the load of the hoisting clamp 64 and avoid overload, four load sensors 2 are symmetrically distributed and fixedly installed on the upper surface of the hoisting clamp 64. A hoisting roller 65 is fixedly installed on the upper surface of the housing of the load sensor 2. A fixed connector 66 is fixedly installed on one side surface of the connecting beam 4. The hoisting steel cable 51 passes through the hoisting roller 65 after being guided by the radial guide wheel 62 and the axial guide wheel 63 and is connected to the surface of the fixed connector 66. A multiple redundancy design is adopted, that is, multiple load sensors 2 are used to detect the load of each hoisting steel cable 51 to ensure that the load change can be accurately detected and false alarms are prevented.

[0065] The load sensor 2 is installed at the connection between the lifting cable 51 and the lifting fixture 64. Its function is to monitor the load of the crane in real time and transmit the data to the control system. The control system receives the data of the load sensor 2 and determines whether it is overloaded through the PID control algorithm. The lifting speed of the crane is dynamically adjusted according to the real-time load error to avoid overload. The system will preset a safe load value. If the load exceeds the preset range, the control system will start the overload protection mechanism, that is, the sound and light alarm 31 will sound immediately to remind the operator to pay attention to safety. At the same time, the lifting fixture 64 is lowered according to the speed adjusted by the algorithm. In order to improve the safety of lowering the lifting fixture 64, the lifting adjustment mechanism 6 also includes a reduction gear box 42. The transmission connection is a rotating shaft 67, and the cable roller 5 is movably sleeved on the outer surface of the rotating shaft 67. The inner wall of the cable roller 5 is symmetrically distributed with connecting grooves 52. The outer surface of the rotating shaft 67 is fixedly connected with a connecting block 68. The outer surface of the connecting block 68 is slidably engaged with the inner wall of the connecting groove 52. The position of the cable roller 5 on the rotating shaft 67 is changed, that is, the cable roller 5 is moved horizontally, thereby changing the lifting angle of the lifting cable 51. By adjusting the angle of the lifting cable 51, the load distribution of the hurdle crane can be effectively changed to disperse the load, thereby reducing the burden. In order to realize the rotation of the cable roller 5 at the same time, the connecting block 68 and the connecting groove 52 are matched to realize the rotation of the cable roller 5 when the rotating shaft 67 rotates.

[0066] The lifting cable 51 on the cable roller 5 is wound around the outer surfaces of the radial guide wheel 62 and the axial guide wheel 63 on the moving beam tube 61. Therefore, when adjusting the lifting angle of the lifting cable 51, it is necessary to ensure that the moving beam tube 61 and the cable roller 5 move synchronously. The lifting adjustment mechanism 6 also includes two linkage rods 69 fixedly connected to the surfaces of the opposite sides of the two moving beam tubes 61. The upper surfaces of the two linkage rods 69 are fixedly connected to a support seat 70 with a limiting ring. The outer surface of the cable roller 5 is fixedly sleeved with a limiting ring block 71. The inner wall of the limiting ring of the support seat 70 is provided with a limiting groove 72. The outer surface of the limiting ring block 71 is rotatably sleeved with the inner wall of the limiting groove 72. The limiting ring block 71 cooperates with the limiting groove 72 to enable the cable roller 5 to rotate on the surface of the support seat 70. Then, when the moving beam tube 61 moves on the outer surface of the connecting beam 4, the synchronous movement of the cable roller 5 can be achieved through the connection of the linkage rod 69.

[0067] In order to achieve the horizontal movement adjustment of the moving beam tube 61 and the cable roller 5, the surfaces of the two linkage rods 69 are symmetrically distributed and fixedly connected with threaded sleeves 73, and one side surface of the walking beam 3 is symmetrically distributed and rotatably connected with an adjusting screw 74 through a bearing. The inner surface of the threaded sleeve 73 is threadedly sleeved with the outer surface of the adjusting screw 74, and the two groups of adjusting screws 74 on both sides of the reduction gear box 42 rotate synchronously or rotate separately according to the algorithm to control the threaded sleeve 73 to move horizontally on its outer surface, thereby realizing the horizontal adjustment of the moving beam tube 61 and the cable roller 5 under the connection of the linkage rod 69 and the support seat 70. In order to drive a The two adjusting screws 74 on the side rotate synchronously to realize the stable movement of the two movable beam tubes 61 on one side. The outer surface of one end of the two adjusting screws 74 is transmission-connected with a pulley assembly 75, and the outer surface of one adjusting screw 74 is transmission-connected with a driving gear set 76. A driving motor 77 is installed on the surface of the walking beam 3. The driving motor 77 drives one of the adjusting screws 74 to rotate through the driving gear set 76. The driving motor 77 drives one of the adjusting screws 74 to rotate through the driving gear set 76. Then, the two adjusting screws 74 are connected to the pulley assembly 75 to realize the synchronous rotation, thereby realizing the adjustment of the lifting angle.

[0068] By setting up the hoisting adjustment mechanism 6, the hoisting angle of the hoisting steel cable 51 can be adjusted. During the adjustment process, the hoisting fixture 64 is lowered at a speed adjusted by the algorithm, and at the same time, the driving motor 77 drives one of the adjusting screws 74 to rotate through the driving gear set 76, and then the two adjusting screws 74 are synchronously rotated under the connection of the pulley assembly 75, thereby controlling the horizontal movement of the threaded sleeve 73 on its outer surface, and then the horizontal adjustment of the movable beam tube 61 and the steel cable roller 5 is realized under the connection of the linkage rod 69 and the support seat 70, thereby changing the hoisting angle of the hoisting steel cable 51. By adjusting the angle of the hoisting steel cable 51, the load distribution of the hurdle crane can be effectively changed to disperse the load and thus reduce the burden.

[0069] The braking mechanism 8 self-locks the hoisting adjustment mechanism 6 after it moves.

[0070] The movable beam tube 61 needs to slide on the outer surface of the connecting beam 4. In order to avoid the sliding of the adjusted movable beam tube 61 and cause unstable lifting, the braking mechanism 8 includes an adjusting block 81 fixedly connected to the upper surface of one end of the movable beam tube 61. A movable groove 82 is penetrated through the surface of one side of the adjusting block 81. The inner wall of the movable groove 82 is slidably connected with a brake roller 83. Braking grooves 84 are provided on the upper surfaces of both ends of the connecting beam 4. The outer surface of the brake roller 83 is slidably engaged with the inner wall of the brake groove 84. After the movable beam tube 61 is adjusted on the outer surface of the connecting beam 4, the brake roller 83 in the movable groove 82 is pressed into the brake groove 84, thereby connecting the movable beam tube 61 to the connecting beam 4, thereby preventing the movable beam tube 61 from moving again.

[0071] To unlock the braking between the moving beam pipe 61 and the connecting beam 4 and achieve the horizontal movement adjustment of the moving beam pipe 61, the braking mechanism 8 further includes a T-shaped mounting rod 85 fixedly connected to the upper surface of the adjusting block 81. Both ends of the mounting rod 85 are fixedly connected with hydraulic rods 86. The lower surface of the telescopic end of the hydraulic rod 86 is fixedly connected to the upper surface of the braking roller 83. A buffer spring 87 is fixedly sleeved on the outer surface of the telescopic end of the hydraulic rod 86. When the adjusting screw 74 rotates, the telescopic end of the hydraulic rod 86 contracts, lifting the braking roller 83 pressed into the braking groove 84 upward to disengage from the connection with the connecting beam 4, thereby realizing the movement of the moving beam pipe 61. At the same time, during braking, the hydraulic rod 86 presses the braking roller 83 into the braking groove 84, and the two are tightly connected through the extrusion of the buffer spring 87.

[0072] By setting the braking mechanism 8, the position of the hoisting adjustment mechanism 6 can be fixed. During the adjustment process, the hydraulic rod 86 presses the braking roller 83 into the braking groove 84, and the two are tightly connected through the extrusion of the buffer spring 87, thus preventing the adjusted moving beam pipe 61 from sliding and causing unstable hoisting.

[0073] Refer to Figures 1-11 , a protection method for an overload protection device of a cross-cable crane, including the following steps:

[0074] S1. During the operation of the cross-cable crane, the load sensor 2 continuously monitors the weight of the load. Through real-time data acquisition and transmission, the control system can obtain the current load of the hoisting steel cable 51 at any time.

[0075] S2. The control system will preset a safety load threshold according to the design load capacity of the crane, which takes into account the maximum load-bearing capacity, working conditions, and safety factor of the crane. When the load of the cross-cable crane reaches the preset safety threshold, the control system immediately issues an overload warning and triggers the sound and light alarm 31 to remind the operator.

[0076] S3. If the load continues to be overloaded, the control system will automatically take protective measures, that is, the reduction motor 43 drives the rotating shaft 67 to reverse through the reduction gearbox 42, and then through the cooperation of the connecting block 68 and the connecting groove 52, when the rotating shaft 67 rotates, the steel cable roller 5 rotates in reverse, so that the hoisting steel cable 51 is unreeled under the guidance of the radial guide wheel 62 and the axial guide wheel 63, and the hoisting fixture 64 slowly descends to reduce its load.

[0077] S4. While the steel cable roller 5 rotates and adjusts, the telescopic end of the hydraulic rod 86 contracts, lifting the braking roller 83 pressed into the braking groove 84 upward to disengage from the connection with the connecting beam 4, thereby realizing the movement of the moving beam pipe 61.

[0078] After the moving beam pipe 61 moves, the drive motor 77 drives one of the adjusting screws 74 to rotate through the drive gear set 76. Then, under the connection of the pulley assembly 75, the two adjusting screws 74 rotate synchronously, controlling the threaded pipe sleeve 73 to move horizontally on its outer surface. Furthermore, under the connection of the linkage rod 69 and the support base 70, the horizontal adjustment of the moving beam pipe 61 and the cable roller 5 is achieved, thereby changing the hoisting angle of the hoisting cable 51. By adjusting the angle of the hoisting cable 51, the load distribution of the hurdle crane is effectively changed, dispersing the load and thus reducing the burden.

[0079] After the movement of the moving beam pipe 61 is completed, the brake roller 83 is pressed into the brake groove 84 through the hydraulic rod 86, and the tight connection between the connecting beam 4 and the moving beam pipe 61 is achieved through the extrusion of the buffer spring 87, preventing the adjusted moving beam pipe 61 from sliding and causing unstable hoisting. When the hoisting fixture 64 descends to within the threshold range, the load on its upper surface is timely reduced, and hoisting is carried out again.

[0080] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes should be covered within the protection scope of the present invention.

Claims

1. An overload protection device for a cross-cable crane, comprising a frame body (1), and further comprising a load sensor (2) and a control system, characterized in that: A walking beam (3) is slidably connected to the outer surface of the guide rail of the frame body (1); an audible and visual alarm (31) is fixedly connected to the upper surface of the walking beam (3); a connecting beam (4) is fixedly connected to the surfaces of the opposite sides of the two walking beams (3); a steel cable roller (5) is arranged above the connecting beam (4); a hoisting steel cable (51) is wound around the outer surface of the steel cable roller (5); a hoisting adjustment mechanism (6) is arranged on the outer surface of the connecting beam (4); and a braking mechanism (8) is also arranged; The control system adopts PID control algorithm to dynamically adjust the lifting speed of the crane according to the real-time load error to avoid overloading. Wherein, the hoisting adjustment mechanism (6) moves horizontally and adjusts the hoisting angle of the hoisting steel cable (51); Wherein, the braking mechanism (8) self-locks the hoisting adjustment mechanism (6) after it moves.

2. The overload protection device of a cross-cable crane according to claim 1, characterized in that: The formula of the PID control algorithm is: [\text{Output}=K_p\cdote(t)+K_i\inte(t),dt+K_d\cdot\frac{de(t)}{dt}]where e(t) is the load error, which is the product of the target load and the actual load. The load error measures the difference between the current crane load and the set target load. This error value is the control system's behavior to adjust the crane according to the change in the actual load. Where [K_p\cdote(t)] is the proportional control term, K_p is the proportional gain, the direct response of the control error; Among them, [K_i\inte(t),dt] is the integral control term, K_i is the integral gain, and the control error accumulates over time; [K_d\cdot\frac{de(t)}{dt}] is the differential control term, K_d is the differential gain, and controls the rate of change of the error.

3. The overload protection device of a cross-cable crane according to claim 2, characterized in that: A mounting beam (41) is fixedly connected to the surface of one side opposite to the middle of the two connecting beams (4), a reduction gear box (42) is fixedly connected to the upper surface of the mounting beam (41), and a reduction motor (43) is transmission-connected to the outer surface of the reduction gear box (42).

4. The overload protection device of a cross-cable crane according to claim 3, characterized in that: The hoisting adjustment mechanism (6) comprises a movable beam tube (61) slidably sleeved on the outer surface of the connecting beam (4), the outer surface of the movable beam tube (61) is installed with a radial guide wheel (62) and an axial guide wheel (63), a hoisting fixture (64) is arranged below the connecting beam (4), four load sensors (2) are symmetrically distributed and fixedly installed on the upper surface of the hoisting fixture (64), a hoisting roller (65) is fixedly installed on the upper surface of the shell of the load sensor (2), a fixed connector (66) is fixedly installed on one side surface of the connecting beam (4), and the hoisting steel cable (51) passes through the hoisting roller (65) after being guided by the radial guide wheel (62) and the axial guide wheel (63), and is connected to the surface of the fixed connector (66).

5. The overload protection device of a cross-cable crane according to claim 4, characterized in that: The hoisting adjustment mechanism (6) further includes a rotating shaft (67) drivingly connected to the reduction gearbox (42). The cable roller (5) is movably sleeved on the outer surface of the rotating shaft (67). Connecting grooves (52) are symmetrically formed on the inner wall of the cable roller (5). A connecting block (68) is fixedly connected to the outer surface of the rotating shaft (67), and the outer surface of the connecting block (68) is slidably clamped with the inner wall of the connecting groove (52).

6. The overload protection device of a cross-cable crane according to claim 5, characterized in that: The hoisting adjustment mechanism (6) further includes two linkage rods (69) fixedly connected to the opposite side surfaces of the two moving beam pipes (61). Support seats (70) with limiting rings are fixedly connected to the upper surfaces of the two linkage rods (69). A limiting ring block (71) is fixedly sleeved on the outer surface of the cable roller (5). A limiting groove (72) is formed on the inner wall of the limiting ring of the support seat (70), and the outer surface of the limiting ring block (71) is rotatably sleeved with the inner wall of the limiting groove (72).

7. An overload protection device for a cross-cable crane according to claim 6, characterized in that: Threaded pipe sleeves (73) are fixedly connected to the surfaces of the two linkage rods (69) symmetrically. One side surface of the walking beam (3) is rotatably connected with adjusting screws (74) through bearings symmetrically. The inner surface of the threaded pipe sleeve (73) is threadedly sleeved with the outer surface of the adjusting screw (74). One ends of the two adjusting screws (74) are drivingly connected with a pulley assembly (75). The outer surface of one of the adjusting screws (74) is drivingly connected with a driving gear set (76). A driving motor (77) is installed on the surface of the walking beam (3), and the driving motor (77) drives one of the adjusting screws (74) to rotate through the driving gear set (76).

8. An overload protection device for a cross-cable crane according to claim 7, characterized in that: The braking mechanism (8) includes an adjusting block (81) fixedly connected to the upper surface of one end of the moving beam pipe (61). An activity groove (82) is formed through one side surface of the adjusting block (81). A braking roller (83) is slidably connected to the inner wall of the activity groove (82). Braking grooves (84) are formed on the upper surfaces of both ends of the connecting beam (4), and the outer surface of the braking roller (83) is slidably clamped with the inner wall of the braking groove (84).

9. An overload protection device for a cross-cable crane according to claim 8, characterized in that: The braking mechanism (8) further includes a T-shaped mounting rod (85) fixedly connected to the upper surface of the adjusting block (81). Hydraulic rods (86) are fixedly connected to the surfaces of both ends of the mounting rod (85). The lower surface of the telescopic end of the hydraulic rod (86) is fixedly connected to the upper surface of the braking roller (83). A buffer spring (87) is fixedly sleeved on the outer surface of the telescopic end of the hydraulic rod (86).

10. A protection method for an overload protection device of the cross-cable crane described in claim 9, characterized in that: It includes the following steps: S1. During the operation of the cable crane, the load sensor (2) continuously monitors the weight of the load. Through real-time data acquisition and transmission, the control system can obtain the current load of the hoisting cable (51) at any time; S2. The control system will preset a safety load threshold according to the designed load capacity of the crane. This value takes into account the maximum load-bearing capacity of the crane, working conditions, and safety factor. When the load of the cable-crane reaches the preset safety threshold, the control system immediately issues an overload warning and triggers the audible and visual alarm (31) to alert the operator. S3. If the load continues to be overloaded, the control system will automatically take protective measures. That is, the reduction motor (43) drives the rotating shaft (67) to reverse through the reduction gearbox (42), and then through the cooperation of the connecting block (68) and the connecting groove (52), when the rotating shaft (67) rotates, the steel cable roller (5) is rotated in reverse, so as to unwind the hoisting steel cable (51) under the guidance of the radial guide wheel (62) and the axial guide wheel (63), so that the hoisting fixture (64) slowly descends to reduce its load. S4. While the steel cable roller (5) is rotating and adjusting, the telescopic end of the hydraulic rod (86) contracts, so that it lifts the brake roller (83) pressed into the brake groove (84) upward to disengage from the connection with the connecting beam (4), thus realizing the movement of the moving beam tube (61). S5. After the moving beam tube (61) moves, the driving motor (77) drives one of the adjusting screws (74) to rotate through the driving gear set (76), and then under the connection of the pulley assembly (75), the two adjusting screws (74) rotate synchronously, so as to control the horizontal movement of the threaded pipe sleeve (73) on its outer surface, and then under the connection of the linkage rod (69) and the support seat (70), the horizontal adjustment of the moving beam tube (61) and the steel cable roller (5) is realized, so as to change the hoisting angle of the hoisting steel cable (51). By adjusting the angle of the hoisting steel cable (51), the load distribution of the cable-crane is effectively changed, so that the load is dispersed, thus reducing the burden. S6. After the movement of the moving beam tube (61) is completed, the brake roller (83) is pressed into the brake groove (84) by the hydraulic rod (86), and through the extrusion of the buffer spring (87), the tight connection between the connecting beam (4) and the moving beam tube (61) is realized, avoiding the sliding of the adjusted moving beam tube (61) resulting in unstable hoisting. When the hoisting fixture (64) descends to within the threshold range, the load on its upper surface is timely unloaded, and hoisting is carried out again.

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