A torque monitoring and alarm device for tower cranes and its alarm method

Abstract

This invention relates to the field of tower crane technology and discloses a tower crane torque monitoring and alarm device and its alarm method. By setting up a torque monitoring component, when the crane is lifting heavy objects, the distance between the luffing trolley and the tower cap is measured by a laser sensor. Combined with the weight of the lifted object, the torque state of the crane can be monitored and precisely controlled in real time, ensuring that the crane works in the best condition, reducing downtime caused by overload or misoperation, improving work efficiency, and when the torque reaches a threshold, the torque monitoring component can promptly issue an alarm and provide real-time protection during crane operation, avoiding safety accidents caused by excessive torque and ensuring the safety of personnel and equipment.

Description

Technical Field

[0001] This invention relates to the field of tower crane technology, specifically to a tower crane torque monitoring and alarm device and its alarm method. Background Technology

[0002] Tower cranes can efficiently complete the loading and unloading of containers. Their strong load-bearing capacity and flexible operation make it possible to complete the loading and unloading of multiple containers in a short period of time, thereby shortening the time containers stay in the port and increasing the port's throughput. However, excessive torque is one of the main causes of overturning accidents when using tower cranes.

[0003] Therefore, torque limiters are essential safety devices for tower cranes. Currently, bow-shaped torque limiters are the most widely used in tower cranes. Their working principle is that when a tower crane is lifting a heavy load, the main chord of the tower cap undergoes tensile deformation due to the load. The greater the load, the greater the deformation. At this time, the bow-shaped steel plate on the torque limiter also deforms, amplifying the deformation of the main chord. This causes the distance between the adjusting bolt on the bow-shaped plate and the limit switch to gradually decrease as the load increases. When the load reaches the rated load, adjusting the adjusting bolt triggers the limit switch, thereby cutting off the power to the hoisting mechanism and luffing mechanism, achieving the purpose of limiting the lifting torque load of the tower crane. However, this type of lifting torque limiter has the problem of not being able to monitor torque changes in real time, which can easily cause safety accidents such as overturning and boom breakage during use. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a tower crane torque monitoring and alarm device and its alarm method, thereby overcoming the aforementioned technical problems in existing related technologies.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a tower crane torque monitoring and alarm device, comprising a tower cap and a lifting arm connected to the tower cap, wherein the tower cap is provided with a luffing mechanism, a limiting component, and a torque monitoring component, the luffing mechanism comprising a luffing trolley and a winding assembly, the luffing trolley being mounted on the lifting arm, and a lifting hook being connected to the lower part of the luffing trolley, the winding assembly comprising a mounting base and a drum, the mounting base being mounted on one end of the lifting arm near the tower cap, the drum being connected to the mounting base, and a traction steel cable being wound on the drum, the traction steel cable being connected to the luffing trolley, and the luffing trolley being pulled by the traction steel cable when the drum rotates. The luffing trolley moves horizontally on the boom. The limiting assembly includes a mounting box containing a drive shaft, a limiting shaft, and a pressure plate. The drive shaft is connected to the drum, and the limiting shaft is connected to the drive shaft. The pressure plate engages with the side of the limiting shaft. When the drum rotates, it sequentially drives the drive shaft and the limiting shaft to rotate. When the torque is overloaded, the pressure plate moves down onto the limiting shaft to restrict its rotation. The limited limiting shaft then restricts the rotation of the drum via the drive shaft. The torque monitoring assembly includes a laser sensor and a light-blocking plate. The laser sensor is mounted on the tower cap, and the light-blocking plate is connected to the luffing trolley.

[0006] Preferably, the lifting arm is fixedly connected to the tower cap, guide rails are fixedly connected to both sides of the lifting arm, pulley blocks are fixedly connected to both ends of the lifting arm, a motor base is fixedly connected to the side of the lifting arm away from the laser sensor, the motor base is located at the end of the lifting arm closer to the tower cap, a protective groove is fixedly installed on the other side of the lifting arm, and the laser sensor is located in the protective groove.

[0007] Preferably, the luffing mechanism further includes a lifting pulley, a plurality of rollers are rotatably connected to the luffing trolley, the luffing trolley is slidably mounted on the guide rail via the plurality of rollers, the lifting pulley is rotatably connected to the luffing trolley via a rotating shaft, and the lifting hook is connected to the lifting pulley via a steel rope.

[0008] Preferably, the mounting base is fixedly mounted on the lifting boom, and the drum is rotatably connected to the mounting base. Both ends of the drum are provided with winding slots, and a traction cable is wound in each winding slot. The traction cable away from the motor base passes over the pulley block near the tower cap and is fixedly connected to the end of the luffing trolley near the drum. The other traction cable passes over the pulley block away from the tower cap and is fixedly connected to the end of the luffing trolley away from the drum. A drive gear is coaxially fixedly connected to one end of the drum, and the other end of the drum is coaxially fixedly connected to the output shaft of the winding motor. The winding motor is fixedly mounted on the motor base.

[0009] Preferably, the mounting box is fixedly mounted on the mounting base. The mounting box is provided with a fixing plate and a sliding groove. The fixing plate is fixedly mounted on the side of the limiting shaft away from the drive shaft. The sliding groove is formed on the side of the fixing plate away from the limiting shaft. The drive shaft and the limiting shaft are rotatably connected in sequence within the mounting box. A drive gear and a driven gear are coaxially fixedly connected in sequence on the drive shaft. The driven gear meshes with the drive gear. The limiting shaft has several arc-shaped grooves evenly formed around its circumference. A spur gear is coaxially fixedly connected to the end of the limiting shaft. The spur gear meshes with the drive gear.

[0010] Preferably, one end of the pressure plate away from the limiting axis is rotatably connected to the mounting box, and an arc-shaped protrusion is fixedly installed at the bottom of the other end of the pressure plate, the arc-shaped protrusion corresponding to the arc-shaped groove. The two sides of the pressure plate are slidably installed in the slide groove via sliders. A connecting seat is fixedly installed at the top of the pressure plate at this end, and a connecting rod is rotatably installed on the connecting seat. A connecting rod groove is opened on the connecting rod. Support springs are provided on both sides of the connecting seat, and the two ends of the support springs are fixedly connected to the top of the pressure plate and the bottom of the fixed plate, respectively.

[0011] Preferably, the limiting component further includes an electric actuator, which is fixedly mounted on the top of the mounting box, and the output shaft of the electric actuator is slidably connected in the connecting rod groove via a slide rod.

[0012] Preferably, the torque monitoring component further includes a pressure sensor, which is fixedly installed below the shaft connecting the lifting pulley and the luffing trolley. The shaft of the lifting pulley presses against the pressure sensor. The laser sensor is fixedly connected to the tower cap. The light-blocking plate is fixedly connected to the connecting rod. The connecting rod is fixedly connected to the luffing trolley. When the luffing trolley moves, it drives the light-blocking plate to move within the protective groove.

[0013] Preferably, a PLC control box is fixedly connected to the tower cap. The PLC control box is connected to the laser sensor, pressure sensor, winding motor and electric push rod through electrical signals. A buzzer is fixedly installed on the PLC control box.

[0014] This invention also provides an alarm method using a tower crane torque monitoring and alarm device, the specific steps of which are as follows:

[0015] First, the luffing trolley of the luffing mechanism moves the hook above the container, hooking it and lifting it. During the lifting process, the torque monitoring component monitors the torque status in real time. When the torque reaches the threshold, the torque monitoring component issues an alarm and stops the luffing trolley. At the same time, the limiting component drives the pressure plate to fall onto the limiting shaft, restricting the drum to rotate only in the reverse direction. This, in conjunction with the winding motor, drives the luffing trolley closer to the tower cap, reducing the amplitude and torque, thus clearing the alarm. After the alarm is cleared, the operator slowly lowers the lifted container back to the ground. At this point, the limiting component lifts the pressure plate again, releasing the restriction on the drum.

[0016] Compared with the prior art, the present invention provides a tower crane torque monitoring and alarm device and its alarm method, which has the following beneficial effects:

[0017] 1. The tower crane torque monitoring and alarm device and its alarm method, through the setting of the torque monitoring component, when the crane is lifting heavy objects, the distance between the luffing trolley and the tower cap is measured by a laser sensor. Combined with the weight of the lifted object, the torque status of the crane can be monitored and precisely controlled in real time, ensuring that the crane works in the best condition, reducing downtime caused by overload or misoperation, improving work efficiency, and when the torque reaches the threshold, the torque monitoring component can promptly alarm and provide real-time protection during crane operation, avoiding safety accidents caused by excessive torque and ensuring the safety of personnel and equipment.

[0018] 2. The tower crane torque monitoring alarm device and its alarm method, through the cooperation of the limiting component and the luffing mechanism, when the torque monitoring component alarms, the electric push rod of the limiting component drives the pressure plate to move down, and the arc-shaped protrusion is locked into the arc-shaped groove of the limiting shaft, so that the drum can only rotate in the reverse direction and cannot rotate in the forward direction. This provides a guarantee for the operator to control the luffing trolley to reduce the amplitude and reduce the torque. When the torque reaches the threshold, it can protect the crane and prevent the crane from continuing to increase the amplitude due to the inability to control the luffing trolley, which would cause the torque to continue to increase and lead to the crane overturning. Attached Figure Description

[0019] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0020] Figure 2 for Figure 1 A magnified schematic diagram of the structure at point A;

[0021] Figure 3 This is a schematic diagram of the planar structure of the amplitude-changing mechanism of the present invention;

[0022] Figure 4 This is a side view of the torque monitoring component of the present invention.

[0023] Figure 5 This is a schematic diagram of the internal structure of the mounting box of the present invention;

[0024] Figure 6 for Figure 5 A magnified schematic diagram of the structure at point B;

[0025] Figure 7 This is a side view of the winding assembly of the present invention.

[0026] Figure 8 This is a side view of the transmission shaft and limiting shaft of the present invention;

[0027] Figure 9 for Figure 8 A magnified schematic diagram of the structure at point C;

[0028] Figure 10 This is a side view of the crane boom structure of the present invention;

[0029] Figure 11 This is a schematic diagram showing the positional relationship of the components of the limiting assembly of the present invention;

[0030] Figure 12 for Figure 11 A magnified schematic diagram of the structure at point D.

[0031] In the diagram: 1. Tower cap; 11. PLC control box; 12. Buzzer; 2. Lifting boom; 21. Guide rail; 22. Pulley block; 23. Motor mount; 24. Protective groove; 3. Luffing mechanism; 31. Luffing trolley; 311. Roller; 32. Lifting pulley; 33. Lifting hook; 4. Rewinding assembly; 41. Mounting base; 42. Drum; 421. Rewinding groove; 422. Traction cable; 43. Drive gear; 44. Rewinding motor; 5. Limiting assembly; 51. Mounting box; 5 11. Fixed plate; 512. Slide groove; 52. Drive shaft; 521. Drive gear; 522. Driven gear; 53. Limiting shaft; 531. Arc-shaped groove; 54. Spur gear; 55. Pressure plate; 551. Arc-shaped protrusion; 552. Connecting seat; 56. Connecting rod; 561. Connecting rod groove; 57. Support spring; 58. Electric push rod; 581. Slide rod; 6. Torque monitoring assembly; 61. Laser sensor; 62. Connecting rod; 63. Light blocking plate; 64. Pressure sensor. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Example 1;

[0034] Please see Figures 1-12 A torque monitoring and alarm device for a tower crane includes a tower cap 1 and a boom 2 connected to the tower cap 1. The tower cap 1 is equipped with a luffing mechanism 3, a limiting component 5, and a torque monitoring component 6. The luffing mechanism 3 includes a luffing trolley 31 and a winding assembly 4. The luffing trolley 31 is mounted on the boom 2, and a lifting hook 33 is connected to its lower end. The winding assembly 4 includes a mounting base 41 and a drum 42. The mounting base 41 is mounted on one end of the boom 2 near the tower cap 1, and the drum 42 is connected to the mounting base 41. A traction cable 422 is wound around the drum 42 and connected to the luffing trolley 31. When the drum 42 rotates, the traction cable 422 pulls the luffing trolley 31 on the boom 2. The horizontal movement and limiting component 5 includes a mounting box 51, in which a drive shaft 52, a limiting shaft 53, and a pressure plate 55 are sequentially arranged. The drive shaft 52 is connected to the drum 42, and the limiting shaft 53 is connected to the drive shaft 52. The pressure plate 55 is fitted on the side of the limiting shaft 53. When the drum 42 rotates, it can sequentially drive the drive shaft 52 and the limiting shaft 53 to rotate. When the torque is overloaded, the pressure plate 55 can move down onto the limiting shaft 53 to limit the rotation of the limiting shaft 53. The limited limiting shaft 53 thus limits the rotation of the drum 42 through the drive shaft 52. The torque monitoring component 6 includes a laser sensor 61 and a light-blocking plate 63. The laser sensor 61 is mounted on the tower cap 1, and the light-blocking plate 63 is connected to the luffing trolley 31.

[0035] In operation, the winding assembly 4 rotates the drum 42 in the forward direction, driving the luffing trolley 31 to move the hook 33 above the container to be lifted. The container is then lifted by the hook 33. During the lifting process, the torque monitoring assembly 6 monitors the torque status on the lifting arm 2 in real time. When the container being lifted is too heavy, causing the torque to reach a threshold, the torque monitoring assembly 6 sends a signal to trigger an alarm, prompting the operator to take appropriate action to ensure the safe lifting of the container. Simultaneously, it triggers the pressure plate 55 of the limiting assembly 5, causing it to move down onto the limiting shaft 53, thus restricting the shaft. At this point, the limiting shaft 53, through the transmission shaft 52, controls the drum 42, preventing it from rotating in the forward direction and allowing only reverse rotation. This ensures that the luffing trolley 31 can only rotate on the lifting arm 2. The boom can move towards the tower cap 1 to reduce the amplitude and torque, preventing the luffing trolley 31 from going out of control and moving away from the tower cap 1 due to overload of the lifted container, which would increase the amplitude and torque and cause the crane to overturn. After the torque monitoring component 6 alarms, the drum 42, under the restriction of the limiting component 5, pulls the luffing trolley 31 gradually closer to the tower cap 1 through the traction cable 422, thereby reducing the amplitude and lowering the torque below the threshold, thus clearing the alarm. Then, the lifted container is slowly lowered back to the ground. After that, the pressure plate 55 of the limiting component 5 separates from the limiting shaft 53, ending the restriction on the limiting shaft 53, allowing the drum 42 to continue rotating in the forward direction, driving the luffing trolley 31 to move away from the tower cap 1 on the boom for luffing operation.

[0036] The difference from the above embodiment is that the lifting arm 2 is fixedly connected to the tower cap 1, and guide rails 21 are fixedly connected to both sides of the lifting arm 2. Pulley blocks 22 are fixedly connected to both ends of the lifting arm 2. A motor base 23 is fixedly connected to the side of the lifting arm 2 away from the laser sensor 61. The motor base 23 is located at the end of the lifting arm 2 close to the tower cap 1. A protective groove 24 is fixedly installed on the other side of the lifting arm 2, and the laser sensor 61 is located in the protective groove 24.

[0037] The protective groove 24 serves to protect the laser sensor 61, preventing it from being damaged.

[0038] The difference from the above embodiment is that the luffing mechanism 3 also includes a lifting pulley 32, a plurality of rollers 311 are rotatably connected to the luffing trolley 31, the luffing trolley 31 is slidably mounted on the guide rail 21 through the plurality of rollers 311, the lifting pulley 32 is rotatably connected to the luffing trolley 31 through a rotating shaft, and the lifting hook 33 is connected to the lifting pulley 32 through a steel rope.

[0039] During container lifting, the luffing trolley 31 drives the hook 33 to slide on the guide rail 21 of the boom 2. When the hook 33 moves above the container to be lifted, the luffing trolley 31 stops moving and lowers the hook 33. After the hook 33 hooks the container, the container is lifted and the luffing trolley 31 moves the lifted container on the boom 2 to the predetermined position. When the torque monitoring component 6 issues an alarm during the lifting process, the limiting component 5 cooperates with the winding component 4 to prevent the luffing trolley 31 from increasing its amplitude and can only decrease it. After the alarm is cleared and the lifted container is properly handled, the limiting component 5 will release the restriction on the drum 42, allowing the luffing trolley 31 to continue to increase or decrease its amplitude.

[0040] The difference from the above embodiment is that the mounting base 41 is fixedly mounted on the boom 2, and the drum 42 is rotatably connected to the mounting base 41. Both ends of the drum 42 are provided with winding grooves 421, and a traction steel cable 422 is wound in each winding groove 421. The traction steel cable 422 away from the motor base 23 passes around the pulley block 22 near the tower cap 1 and is fixedly connected to the end of the luffing trolley 31 near the drum 42. The other traction steel cable 422 passes around the pulley block 22 away from the tower cap 1 and is fixedly connected to the end of the luffing trolley 31 away from the drum 42. One end of the drum 42 is coaxially fixedly connected to the drive gear 43, and the other end of the drum 42 is coaxially fixedly connected to the output shaft of the winding motor 44. The winding motor 44 is fixedly mounted on the motor base 23.

[0041] When a greater amplitude is needed, the winding motor 44 drives the drum 42 to rotate forward, simultaneously winding the traction cable 422 connected to the end of the luffing trolley 31 away from the drum 42, and simultaneously extending the traction cable 422 connected to the other end of the luffing trolley 31, thus increasing the amplitude. When a smaller amplitude is needed, the winding motor 44 drives the drum 42 to rotate in the reverse direction, simultaneously extending the traction cable 422 connected to the end of the luffing trolley 31 away from the drum 42, and simultaneously winding the traction cable 422 connected to the other end of the luffing trolley 31. 22. The luffing trolley 31 is driven to move the boom 2 close to the tower cap 1, thereby increasing or decreasing the amplitude. When the luffing trolley 31 is closest to the tower cap 1, the crane can withstand the maximum torque. When the luffing trolley 31 is farthest from the tower cap 1, the crane can withstand the minimum torque. During this process, the rotating drum 42 drives the drive gear 43 to rotate synchronously. When the torque monitoring component 6 issues an alarm, the winding motor 44 will only drive the drum 42 to rotate in the reverse direction, and will not drive the drum 42 to rotate in the forward direction. After the alarm is cleared, the winding motor 44 can continue to rotate in the forward direction.

[0042] The difference from the above embodiment is that the mounting box 51 is fixedly mounted on the mounting base 41. The mounting box 51 is provided with a fixing plate 511 and a sliding groove 512. The fixing plate 511 is fixedly mounted on the side of the limiting shaft 53 away from the transmission shaft 52. The sliding groove 512 is opened on the side of the fixing plate 511 away from the limiting shaft 53. The transmission shaft 52 and the limiting shaft 53 are rotatably connected in sequence within the mounting box 51. The transmission shaft 52 is coaxially fixedly connected with a transmission gear 521 and a driven gear 522 in sequence. The driven gear 522 meshes with the drive gear 43. The limiting shaft 53 has several arc-shaped grooves 531 evenly opened in a circular shape on its shaft body. The end of the limiting shaft 53 is coaxially fixedly connected with a spur gear 54, which meshes with the transmission gear 521.

[0043] The difference from the above embodiment is that the end of the pressure plate 55 away from the limiting shaft 53 is rotatably connected to the mounting box 51, and an arc-shaped protrusion 551 is fixedly installed at the bottom of the other end of the pressure plate 55. The arc-shaped protrusion 551 corresponds to the arc-shaped groove 531. The two sides of the pressure plate 55 are slidably installed in the slide groove 512 by sliders. A connecting seat 552 is fixedly installed at the top of the end of the pressure plate 55. A connecting rod 56 is rotatably installed on the connecting seat 552. A connecting rod groove 561 is opened on the connecting rod 56. Support springs 57 are provided on both sides of the connecting seat 552. The two ends of the support springs 57 are fixedly connected to the top of the pressure plate 55 and the bottom of the fixing plate 511, respectively.

[0044] The difference from the above embodiment is that the limiting component 5 also includes an electric push rod 58, which is fixedly installed on the top of the mounting box 51, and the output shaft of the electric push rod 58 is slidably connected in the connecting rod groove 561 through the slide rod 581.

[0045] Initially, the output shaft of the electric push rod 58 is in a retracted state, causing the slide rod 581 to move to the top of the connecting rod groove 561. This pulls the pressure plate 55 upwards via the connecting rod 56, separating the arc-shaped protrusion 551 under the pressure plate 55 from the arc-shaped groove 531 of the limiting shaft 53 and compressing the support spring 57. When the drum 42 rotates forward, the drive gear 43 drives the driven gear 522 to rotate, causing the transmission shaft 52 to drive the limiting shaft 53 to rotate via the transmission gear 521. When the torque monitoring component 6 issues an alarm, the drum 42 stops rotating. Simultaneously, the electric push rod 58 extends its output shaft, causing the slide rod 581 to move to the lower end of the connecting rod groove 561. The compressed support spring 57 pushes the pressure plate 55 downwards, causing the arc-shaped protrusion 551 under the pressure plate 55 to fall into the arc-shaped groove 531 of the limiting shaft 53. When the drum 42 wants to continue rotating forward, the pressure plate 55... With the cooperation of the support spring 57, the arc-shaped protrusion 551 abuts against the limiting shaft 53, preventing the limiting shaft 53 from rotating in the forward direction. This prevents the drum 42 from continuing to rotate in the forward direction. When the drum 42 wants to rotate in the reverse direction, the arc-shaped protrusion 551 slides along the arc-shaped groove 531, causing the limiting shaft 53 to lift the pressure plate 55 through the arc-shaped protrusion 551 and compress the support spring 57. After the arc-shaped protrusion 551 passes through one arc-shaped groove 531, it will fall into the next arc-shaped groove 531, continuing to restrict the limiting shaft 53 until the alarm is cleared. Then, the electric push rod 58 retracts the output shaft, causing the slide rod 581 to move to the top of the connecting rod groove 561. The connecting rod 56 then pulls the pressure plate 55 up, pulling the arc-shaped protrusion 551 out of the arc-shaped groove 531, thereby releasing the restriction on the drum 42. During this process, the pressure plate 55 moves along the trajectory of the slide groove 512.

[0046] The difference from the above embodiment is that the torque monitoring component 6 also includes a pressure sensor 64. The pressure sensor 64 is fixedly installed below the shaft connecting the lifting pulley 32 and the luffing trolley 31. The shaft of the lifting pulley 32 presses on the pressure sensor 64. The laser sensor 61 is fixedly connected to the tower cap 1. The light-blocking plate 63 is fixedly connected to the connecting rod 62. The connecting rod 62 is fixedly connected to the luffing trolley 31. When the luffing trolley 31 moves, it drives the light-blocking plate 63 to move within the protective groove 24.

[0047] Example 2;

[0048] The difference from the above embodiment is that a PLC control box 11 is fixedly connected to the tower cap 1. The PLC control box 11 is connected to the laser sensor 61, the pressure sensor 64, the winding motor 44 and the electric push rod 58 through electrical signals. A buzzer 12 is fixedly installed on the PLC control box 11.

[0049] During container lifting, laser sensor 61 emits a laser beam towards light-blocking plate 63 to measure the distance between luffing trolley 31 and tower cap 1, and transmits the data to PLC control box 11 via electrical signal. Simultaneously, as lifting hook 33 lifts the container, its weight is transmitted to pressure sensor 64 via the shaft of lifting pulley 32. Pressure sensor 64 transmits the container weight data to PLC control box 11 via electrical signal. PLC control box 11 calculates the torque based on the received data, thereby monitoring the crane's torque in real time. When the torque reaches a threshold requiring an alarm, the PLC control box activates the alarm. The container control box 11 activates the buzzer 12 to sound an alarm, and simultaneously sends electrical signals to the winding motor 44 and the electric push rod 58 to control the winding motor 44 to rotate only in the reverse direction. At the same time, the electric push rod 58 is activated to restrict the drum 42 with the limiting component 5. After the lifted container is lowered, the PLC control box 11 deactivates the alarm of the buzzer 12. After the lifted container is placed back on the ground, the PLC control box 11 sends electrical signals to the winding motor 44 and the electric push rod 58 again, so that the winding motor 44 can drive the drum 42 to rotate in the forward direction again. At the same time, the electric push rod 58 lifts the pressure plate 55 to release the restriction on the drum 42.

[0050] This invention also provides an alarm method using a tower crane torque monitoring and alarm device, the specific steps of which are as follows:

[0051] First, the luffing trolley 31 of the luffing mechanism 3 moves the hook 33 above the container, hooks the container, and lifts it. During the lifting process, the torque monitoring component 6 monitors the torque status in real time. When the torque reaches the threshold, the torque monitoring component 6 issues an alarm and stops the luffing trolley 31. At the same time, the limiting component 5 drives the pressure plate 55 to fall onto the limiting shaft 53, limiting the drum 42 to rotate only in the reverse direction and not in the forward direction. This, in conjunction with the winding motor 44, drives the luffing trolley 31 to move closer to the tower cap 1, reducing the amplitude and lowering the torque, thereby clearing the alarm. After the alarm is cleared, the operator slowly lowers the lifted container back to the ground. At this time, the limiting component 5 lifts the pressure plate 55 again, releasing the restriction on the drum 42.

[0052] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A tower crane torque monitoring and alarm device, comprising a tower cap and a crane boom connected to the tower cap, characterized in that: The tower cap is equipped with a luffing mechanism, a limiting component, and a torque monitoring component. The luffing mechanism includes a luffing trolley and a winding assembly. The luffing trolley is mounted on the boom, and a lifting hook is connected to its lower end. The winding assembly includes a mounting base and a drum. The mounting base is mounted on the end of the boom near the tower cap, and the drum is connected to the mounting base. One end of the drum is coaxially fixedly connected to a drive gear, and the other end of the drum is coaxially fixedly connected to the output shaft of the winding motor. A traction steel cable is wound on the drum, and the traction steel cable is connected to the luffing trolley. When the drum rotates, the luffing trolley is pulled horizontally on the boom through the traction steel cable. The limiting component includes a mounting box, in which a drive shaft, a limiting shaft, and a pressure plate are arranged in sequence. The drive shaft is connected to the drum, and the limiting shaft is connected to the drive shaft. The pressure plate is fitted to the side of the limiting shaft. When the drum rotates, it can drive the drive shaft and the limiting shaft to rotate in sequence. When the torque is overloaded, the pressure plate can move down onto the limiting shaft to limit the rotation of the limiting shaft. The limited limiting shaft thus limits the rotation of the drum through the drive shaft. The torque monitoring component includes a laser sensor and a light-blocking plate. The laser sensor is mounted on the tower cap, and the light-blocking plate is connected to the luffing trolley. The mounting box is fixedly mounted on the mounting base. The mounting box contains a fixing plate and a sliding groove. The fixing plate is fixedly mounted on the side of the limiting shaft away from the drive shaft. The sliding groove is formed on the side of the fixing plate away from the limiting shaft. The drive shaft and the limiting shaft are rotatably connected to the mounting box in sequence. A drive gear and a driven gear are coaxially fixedly connected to the drive shaft in sequence. The driven gear meshes with the drive gear. The limiting shaft has several evenly spaced arc-shaped grooves on its shaft body. A spur gear is coaxially fixedly connected to the end of the limiting shaft, and the spur gear meshes with the drive gear. The end of the pressure plate away from the limiting axis is rotatably connected to the mounting box. An arc-shaped protrusion is fixedly installed at the bottom of the other end of the pressure plate, and the arc-shaped protrusion corresponds to the arc-shaped groove. The two sides of the pressure plate are slidably installed in the slide groove by sliders. A connecting seat is fixedly installed at the top of the pressure plate at this end. A connecting rod is rotatably installed on the connecting seat. A connecting rod groove is opened on the connecting rod. Support springs are provided on both sides of the connecting seat. The two ends of the support springs are fixedly connected to the top of the pressure plate and the bottom of the fixed plate, respectively. The limiting component also includes an electric actuator, which is fixedly mounted on the top of the mounting box, and the output shaft of the electric actuator is slidably connected in the connecting rod groove via a slide rod.

2. The tower crane torque monitoring and alarm device according to claim 1, characterized in that: The lifting boom is fixedly connected to the tower cap. Guide rails are fixedly connected to both sides of the lifting boom. Pulley blocks are fixedly connected to both ends of the lifting boom. A motor base is fixedly connected to the side of the lifting boom away from the laser sensor. The motor base is located at the end of the lifting boom closer to the tower cap. A protective groove is fixedly installed on the other side of the lifting boom. The laser sensor is located in the protective groove.

3. The tower crane torque monitoring and alarm device according to claim 2, characterized in that: The luffing mechanism also includes a lifting pulley, and several rollers are rotatably connected to the luffing trolley. The luffing trolley is slidably mounted on the guide rail via several rollers. The lifting pulley is rotatably connected to the luffing trolley via a rotating shaft, and the lifting hook is connected to the lifting pulley via a steel rope.

4. The tower crane torque monitoring and alarm device according to claim 3, characterized in that: The mounting base is fixedly mounted on the boom, and the drum is rotatably connected to the mounting base. Both ends of the drum are provided with winding slots, and a traction cable is wound in each winding slot. The traction cable away from the motor base passes over the pulley block near the tower cap and is fixedly connected to the end of the luffing trolley near the drum. The other traction cable passes over the pulley block away from the tower cap and is fixedly connected to the end of the luffing trolley away from the drum. The winding motor is fixedly mounted on the motor base.

5. The tower crane torque monitoring and alarm device according to claim 4, characterized in that: The torque monitoring component also includes a pressure sensor, which is fixedly installed below the shaft connecting the lifting pulley and the luffing trolley. The shaft of the lifting pulley presses on the pressure sensor. The laser sensor is fixedly connected to the tower cap. The light-blocking plate is fixedly connected to the connecting rod. The connecting rod is fixedly connected to the luffing trolley. When the luffing trolley moves, it drives the light-blocking plate to move within the protective groove.

6. The tower crane torque monitoring and alarm device according to claim 5, characterized in that: A PLC control box is fixedly connected to the tower cap. The PLC control box is connected to the laser sensor, pressure sensor, winding motor and electric push rod through electrical signals. A buzzer is fixedly installed on the PLC control box.

7. An alarm method, characterized in that: The tower crane torque monitoring and alarm device according to any one of claims 1-6 is used, and the specific steps are as follows: First, the luffing trolley of the luffing mechanism moves the hook above the container, hooking it and lifting it. During the lifting process, the torque monitoring component monitors the torque status in real time. When the torque reaches the threshold, the torque monitoring component issues an alarm and stops the luffing trolley. At the same time, the limiting component drives the pressure plate to fall onto the limiting shaft, restricting the drum to rotate only in the reverse direction. This, in conjunction with the winding motor, drives the luffing trolley closer to the tower cap, reducing the amplitude and torque, thus clearing the alarm. After the alarm is cleared, the operator slowly lowers the lifted container back to the ground. At this point, the limiting component lifts the pressure plate again, releasing the restriction on the drum.

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