Tower crane moment monitoring alarm device and alarm method thereof

Abstract

The invention relates to the technical field of tower cranes, and discloses a tower crane moment monitoring alarm device and an alarm method thereof.Through arrangement of a moment monitoring assembly, when a crane lifts a heavy object, the distance between a variable-amplitude trolley and a tower cap is measured through a laser sensor, and then the moment monitoring assembly is combined with the weight of the lifted object; therefore, the moment state of the crane can be monitored and accurately controlled in real time, it is ensured that the crane works in the optimal state, the downtime caused by overload or misoperation is shortened, the operation efficiency is improved, when the moment reaches the threshold value, the moment monitoring assembly can give an alarm in time, real-time protection is provided in the operation process of the crane, and the safety of the crane is improved. Safety accidents caused by overlarge torque are avoided, and the safety of personnel and equipment is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of tower cranes, and in particular to a tower crane moment monitoring and alarming device and an alarming method thereof. Background Art

[0002] Tower cranes can efficiently complete the loading and unloading of containers. Their strong load-bearing capacity and flexible operating performance make it possible to complete the loading and unloading of multiple containers in a short time, thereby shortening the detention time of containers at the port and increasing the throughput of the port. However, during the use of tower cranes, over-torque is one of the main causes of tipping accidents.

[0003] Therefore, a moment limiter is an essential safety device for tower cranes. Currently, the bow-shaped moment limiter is the most widely used on tower cranes. Its working principle is that when the tower crane hoists a heavy object, due to the action of the load, the main chord of the tower cap undergoes tensile deformation. The greater the load, the greater the deformation. At this time, the bow-shaped steel plate on the moment limiter also deforms accordingly, and amplifies the deformation of the main chord, so that the distance between the adjusting bolt on the bow-shaped plate and the limit switch gradually decreases with the increase of the load. When the load reaches the rated load, the limit switch is triggered by adjusting the bolt, thereby cutting off the power supply of the hoisting mechanism and the luffing mechanism, achieving the purpose of limiting the lifting moment load of the tower crane. However, this lifting moment limiter has the problem of not being able to monitor the moment change in real time, and it is easy to cause safety accidents such as the overturning and folding of the hoisting machinery during use. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a tower crane moment monitoring and alarming device and an alarming method thereof to overcome the above-mentioned technical problems existing in the prior related technologies.

[0005] To solve the above technical problems, the present invention provides the following technical solution: A moment monitoring and alarming device for a tower crane, comprising a tower cap and a boom connected to the tower cap. A luffing mechanism, a limiting component and a moment monitoring component are arranged on the tower cap. The luffing mechanism comprises a luffing trolley and a winding component. The luffing trolley is installed on the boom. A lifting hook is connected below the luffing trolley. The winding component comprises a mounting seat and a drum. The mounting seat is installed at one end of the boom close to the tower cap. The drum is connected to the mounting seat. A traction steel cable is wound around the drum. The traction steel cable is connected to the luffing trolley. When the drum rotates, the luffing trolley is pulled by the traction steel cable to move horizontally on the boom. The limiting component comprises a mounting box. A transmission shaft, a limiting shaft and a pressing plate are sequentially arranged in the mounting box. The transmission shaft is connected to the drum. The limiting shaft is connected to the transmission shaft. The pressing plate is fitted on the side of the limiting shaft. When the drum rotates, it can drive the transmission shaft and the limiting shaft to rotate in sequence. When the moment is overloaded, the pressing plate can move down to the limiting shaft to limit the rotation of the limiting shaft. The limited limiting shaft thus limits the rotation of the drum through the transmission shaft. The moment monitoring component comprises a laser sensor and a light blocking plate. The laser sensor is installed on the tower cap. The light blocking plate is connected to the luffing trolley.

[0006] Preferably, the boom is fixedly connected to the tower cap. Guide rails are fixedly connected to both sides of the boom. Pulley groups are fixedly connected to both ends of the boom. A motor seat is fixedly connected to the side of the boom away from the laser sensor. The motor seat is located at one end of the boom close to the tower cap. A protective groove is fixedly installed on the other side of the boom. The laser sensor is located in the protective groove.

[0007] Preferably, the luffing mechanism further comprises a hoisting pulley. A plurality of rollers are rotatably connected to the luffing trolley. The luffing trolley is slidably installed on the guide rails through the plurality of rollers. The hoisting pulley is rotatably connected to the luffing trolley through a rotating shaft. The lifting hook is connected to the hoisting pulley through a steel rope.

[0008] Preferably, the mounting base is fixedly installed on the boom, the drum is rotatably connected to the mounting base, winding grooves are formed at both ends of the drum, and one traction cable is wound in each winding groove. The traction cable away from the motor base bypasses the pulley block close to the tower cap and is fixedly connected to one end of the luffing trolley close to the drum, while the other traction cable bypasses the pulley block away from the tower cap and is fixedly connected to the other end of the luffing trolley away from the drum. A driving gear is coaxially and fixedly connected to one end of the drum, the other end of the drum is coaxially and fixedly connected to the output shaft of the winding motor, and the winding motor is fixedly installed on the motor base.

[0009] Preferably, the mounting box is fixedly installed on the mounting base. A fixed plate and a sliding groove are respectively arranged in the mounting box. The fixed plate is fixedly installed on the side of the limiting shaft away from the transmission shaft, and the sliding groove is formed on the side of the fixed plate away from the limiting shaft. The transmission shaft and the limiting shaft are sequentially rotatably connected in the mounting box. A transmission gear and a driven gear are coaxially and fixedly connected to the transmission shaft in sequence. The driven gear meshes with the driving gear. A plurality of arc-shaped grooves are uniformly formed in a circumferential shape on the shaft body of the limiting shaft. A straight gear is coaxially and fixedly connected to the end of the limiting shaft. The straight gear meshes with the transmission gear.

[0010] Preferably, one end of the pressing plate away from the limiting shaft is rotatably connected in the mounting box. An arc-shaped convex block is fixedly installed at the bottom of the other end of the pressing plate. The arc-shaped convex block corresponds to the arc-shaped groove. Both sides of the pressing plate are slidably installed in the sliding groove through sliders. A connecting seat is fixedly installed at the top of this end of the pressing plate. A connecting rod is rotatably installed on the connecting seat. A connecting rod groove is formed in the connecting rod. Support springs are arranged on both sides of the connecting seat. Both ends of the support spring are respectively fixedly connected to the top of the pressing plate and the bottom of the fixed plate.

[0011] Preferably, the limiting assembly further includes an electric push rod. The electric push rod is fixedly installed on the top of the mounting box. The output shaft of the electric push rod is slidably connected in the connecting rod groove through a sliding rod.

[0012] Preferably, the torque monitoring assembly further includes a pressure sensor. The pressure sensor is fixedly installed below the rotating shaft connecting the hoisting pulley and the luffing trolley. The rotating shaft of the hoisting 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 in the protection groove.

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

[0014] The present invention also provides an alarm method, which uses a tower crane torque monitoring alarm device, and the specific steps are:

[0015] First, the luffing trolley of the luffing mechanism moves the lifting hook to the top of the container, and after the lifting hook hooks the container, the container is lifted. During the process of lifting the container, 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 movement of the luffing trolley. At the same time, the limiting component drives the pressure plate to fall onto the limiting shaft, limiting the reel to only rotate in the reverse direction but not in the forward direction, thereby cooperating with the winding motor to drive the luffing trolley closer to the tower cap, reducing the amplitude and torque, thereby lifting the alarm. After the alarm is lifted, the operator slowly puts the lifted container back to the ground. At this time, the limiting component lifts the pressure plate again to release the restriction on the reel.

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

[0017] 1. The tower crane torque monitoring alarm device and its alarm method, through the setting of the torque monitoring component, when the crane lifts heavy objects, measures the distance between the luffing trolley and the tower cap through the laser sensor, and then combines the weight of the hoisted object to monitor and accurately control the torque state of the crane in real time, ensuring that the crane operates in the best condition, reducing downtime caused by overloading or misoperation, and improving operating efficiency. When the torque reaches the threshold, the torque monitoring component can alarm in time and provide real-time protection during the crane operation, avoiding safety accidents caused by excessive torque and ensuring the safety of personnel and equipment.

[0018] 2. The torque monitoring and alarm device of the tower crane and the alarm method thereof cooperate with 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 downward, and the arc-shaped protrusion is stuck in the arc-shaped groove of the limiting shaft, so that the drum can only rotate in the reverse direction but not 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 inability to control the luffing trolley, causing the torque to continue to increase and causing the crane to overturn. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0020] Figure 2 is Figure 1 a partial enlarged structural schematic diagram of part A of

[0021] Figure 3 a planar structural schematic diagram of the luffing mechanism of the present invention;

[0022] Figure 4 a side view structural schematic diagram of the torque monitoring component of the present invention;

[0023] Figure 5 a structural schematic diagram of the interior of the installation box of the present invention;

[0024] Figure 6 is Figure 5 a partial enlarged structural schematic diagram of part B of

[0025] Figure 7 a side view structural schematic diagram of the winding component of the present invention;

[0026] Figure 8 a side view structural schematic diagram of the transmission shaft and the limiting shaft of the present invention;

[0027] Figure 9 is Figure 8 a partial enlarged structural schematic diagram of part C of

[0028] Figure 10 a side view structural schematic diagram of the boom of the present invention;

[0029] Figure 11 a schematic diagram of the positional relationship of the components of the limiting component of the present invention;

[0030] Figure 12 is Figure 11 a partial enlarged structural schematic diagram of part D of

[0031] In the figure: 1, tower cap; 11, PLC control box; 12, buzzer; 2, boom; 21, guide rail; 22, pulley block; 23, motor base; 24, protection groove; 3, luffing mechanism; 31, luffing trolley; 311, roller; 32, hoisting pulley; 33, lifting hook; 4, winding component; 41, mounting seat; 42, winding drum; 421, winding groove; 422, towing cable; 43, driving gear; 44, winding motor; 5, limiting component; 51, installation box; 511, fixing plate; 512, chute; 52, transmission shaft; 521, transmission gear; 522, driven gear; 53, limiting shaft; 531, arc-shaped groove; 54, spur gear; 55, pressing plate; 551, arc-shaped convex block; 552, connecting seat; 56, connecting rod; 561, connecting rod groove; 57, support spring; 58, electric push rod; 581, sliding rod; 6, torque monitoring component; 61, laser sensor; 62, connecting rod; 63, light blocking plate; 64, pressure sensor. Detailed implementation manners

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to 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. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] Embodiment 1;

[0034] Please refer to Figures 1 - 12 , a moment monitoring and alarming device for a tower crane, which includes a tower cap 1 and a boom 2 connected to the tower cap 1. A luffing mechanism 3, a limiting assembly 5 and a moment monitoring assembly 6 are arranged on the tower cap 1. The luffing mechanism 3 includes a luffing trolley 31 and a winding assembly 4. The luffing trolley 31 is installed on the boom 2. A lifting hook 33 is connected below the luffing trolley 31. The winding assembly 4 includes a mounting seat 41 and a drum 42. The mounting seat 41 is installed at one end of the boom 2 close to the tower cap 1. The drum 42 is connected to the mounting seat 41. A traction steel cable 422 is wound around the drum 42. The traction steel cable 422 is connected to the luffing trolley 31. When the drum 42 rotates, the luffing trolley 31 is pulled by the traction steel cable 422 to move horizontally on the boom 2. The limiting assembly 5 includes a mounting box 51. A transmission shaft 52, a limiting shaft 53 and a pressing plate 55 are sequentially arranged in the mounting box 51. The transmission shaft 52 is connected to the drum 42. The limiting shaft 53 is connected to the transmission shaft 52. The pressing plate 55 is fitted on the side of the limiting shaft 53. When the drum 42 rotates, it can drive the transmission shaft 52 and the limiting shaft 53 to rotate in sequence. When the moment is overloaded, the pressing plate 55 can move down to 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 transmission shaft 52. The moment monitoring assembly 6 includes a laser sensor 61 and a light blocking plate 63. The laser sensor 61 is installed on the tower cap 1. The light blocking plate 63 is connected to the luffing trolley 31.

[0035] When in use, the winding assembly 4 rotates the drum 42 in the forward direction to drive the luffing trolley 31 to drive the lifting hook 33 to move above the container to be lifted, and the container is lifted by the lifting hook 33. During the lifting process, the torque monitoring assembly 6 monitors the torque state on the crane arm 2 in real time. When the lifted container is too heavy and the torque reaches the threshold, the torque monitoring assembly 6 sends a signal and alarms, prompting the operator to take corresponding actions to ensure the safe lifting of the container. At the same time, the pressure plate 55 of the limiting assembly 5 is triggered, driving the pressure plate 55 to move down to the limiting shaft 53 to limit the limiting shaft 53. At this time, the limiting shaft 53 controls the drum 42 through the transmission shaft 52, so that it can only rotate in the reverse direction but not in the forward direction, so that the luffing trolley 31 can only rotate on the crane arm 2. It can move toward the tower cap 1 to reduce the amplitude and torque, and the luffing trolley 31 will not lose control and move away from the tower cap 1 due to the overload of the lifted container weight, and continue to increase the amplitude and increase the torque to cause the crane to overturn. After the torque monitoring component 6 alarms, the drum 42 pulls the luffing trolley 31 gradually toward the tower cap 1 through the traction cable 422 under the restriction of the limiting component 5, thereby reducing the amplitude and reducing the torque to below the threshold, thereby lifting the alarm, and then slowly putting the lifted container back to the ground, and then the pressure plate 55 of the limiting component 5 separates from the limiting shaft 53, ending the restriction on the limiting shaft 53, so that the drum 42 can continue to rotate forward, driving the luffing trolley 31 to move on the boom away from the tower cap 1 to perform the luffing operation.

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

[0037] The protection groove 24 protects the laser sensor 61 and prevents the laser sensor 61 from being damaged.

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

[0039] Among them, when lifting the container, the luffing trolley 31 drives the lifting hook 33 to slide on the guide rail 21 of the crane arm 2. When the lifting hook 33 moves to above the container to be lifted, the luffing trolley 31 stops moving and lowers the lifting hook 33. After the lifting hook 33 hooks the container, the container is lifted, and the lifted container is driven to move on the crane arm 2 by the luffing trolley 31 to lift the container to a 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 continuing to increase the amplitude and can only perform an operation to reduce the amplitude. After the alarm is lifted and the lifted container is properly disposed of, the limiting component 5 will release the restriction on the drum 42, so that the luffing trolley 31 can continue to perform the luffing operation of increasing or decreasing the amplitude.

[0040] The difference from the above embodiment is that the mounting base 41 is fixedly mounted on the boom 2, the drum 42 is rotatably connected to the mounting base 41, and winding grooves 421 are provided at both ends of the drum 42, and a traction steel cable 422 is wound in each winding groove 421, wherein the traction steel cable 422 away from the motor base 23 is passed over the pulley group 22 close to the tower cap 1, and is fixedly connected to the end of the luffing trolley 31 close to the drum 42, while the other traction steel cable 422 is passed over the pulley group 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 driving gear 43, and the other end of the drum 42 is coaxially fixedly connected to the output shaft of the winding motor 44, and the winding motor 44 is fixedly mounted on the motor base 23.

[0041] When the amplitude needs to be increased, the winding motor 44 drives the drum 42 to rotate forward, and while winding the traction cable 422 connected to one end of the luffing trolley 31 away from the drum 42, the traction cable 422 connected to the other end of the luffing trolley 31 is lengthened, driving the luffing trolley 31 to move the boom 2 away from the tower cap 1, thereby increasing the amplitude. When the amplitude needs to be reduced, the winding motor 44 drives the drum 42 to rotate in the opposite direction, and while lengthening the traction cable 422 connected to one end of the luffing trolley 31 away from the drum 42, the traction cable 422 connected to the other end of the luffing trolley 31 is wound. 22. Drive the luffing trolley 31 to move the boom 2 closer to the tower cap 1, thereby increasing or decreasing the amplitude. When the luffing trolley 31 is closest to the tower cap 1, the torque that the crane can withstand is the largest. When the luffing trolley 31 is farthest from the tower cap 1, the torque that the crane can withstand is the smallest. During this process, the rotating drum 42 drives the driving 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 lifted, the winding motor 44 can continue to rotate in the forward direction.

[0042] The difference from the above embodiment is that the installation box 51 is fixedly installed on the installation seat 41. A fixed plate 511 and a chute 512 are respectively arranged in the installation box 51. The fixed plate 511 is fixedly installed on the side of the limiting shaft 53 away from the transmission shaft 52. The chute 512 is opened on the side of the fixed plate 511 away from the limiting shaft 53. The transmission shaft 52 and the limiting shaft 53 are sequentially rotatably connected in the installation box 51. A transmission gear 521 and a driven gear 522 are coaxially and fixedly connected to the transmission shaft 52 in sequence. The driven gear 522 meshes with the driving gear 43. A plurality of arc-shaped grooves 531 are evenly arranged in a circumferential shape on the shaft body of the limiting shaft 53. A spur gear 54 is coaxially and fixedly connected to the end of the limiting shaft 53. The spur gear 54 meshes with the transmission gear 521.

[0043] The difference from the above embodiment is that one end of the pressing plate 55 away from the limiting shaft 53 is rotatably connected in the installation box 51. An arc-shaped convex block 551 is fixedly installed at the bottom of the other end of the pressing plate 55. The arc-shaped convex block 551 corresponds to the arc-shaped groove 531. Both sides of the pressing plate 55 are slidably installed in the chute 512 through sliders. A connecting seat 552 is fixedly installed at the top of this end of the pressing 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 arranged on both sides of the connecting seat 552. Both ends of the support spring 57 are fixedly connected to the top of the pressing plate 55 and the bottom of the fixed plate 511 respectively.

[0044] The difference from the above embodiment is that the limiting component 5 further includes an electric push rod 58. The electric push rod 58 is fixedly installed on the top of the installation box 51. The output shaft of the electric push rod 58 is slidably connected in the connecting rod groove 561 through a sliding rod 581.

[0045] The cam 55 is in the state of being compressed, and the cam 55 is in the state of being compressed, and the cam 55 is in the state of being compressed, and the cam 55 is in the state of being compressed, and the cam 55 is in the state of being compressed, and the cam 55 is in the state of being compressed, and the cam 55 is in the state of being compressed, and the cam 55 is in the state of being compressed, and the cam 55 is in the state of being compressed, and the cam 55 is in the state of being compressed, and the cam 55 is in the state of being compressed, and the cam 55 is in the state of being compressed, and the cam 55 is in the state of being compressed, and the cam 55 is in the state of being compressed, and the cam 55 is in the state of being compressed, and the cam With the cooperation of the support spring 57, the arc-shaped protrusion 551 presses against the limiting shaft 53, making it impossible for the limiting shaft 53 to rotate forward, thereby preventing the reel 42 from continuing to rotate forward. When the reel 42 wants to rotate in the opposite direction, the arc-shaped protrusion 551 will slide along the arc-shaped groove 531, so that the limiting shaft 53 will 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 and continue to limit the limiting shaft 53 until the alarm is lifted. The electric push rod 58 retracts the output shaft, and after the slide bar 581 moves to the top of the connecting rod groove 561, the pressure plate 55 is pulled up by the connecting rod 56, and the arc-shaped protrusion 551 is pulled out from the arc-shaped groove 531, thereby releasing the restriction on the reel 42. In 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, which is fixedly installed below the rotating shaft connecting the lifting pulley 32 and the boom trolley 31. The rotating 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 baffle 63 is fixedly connected to the connecting rod 62, and the connecting rod 62 is fixedly connected to the boom trolley 31. When the boom trolley 31 moves, it drives the light baffle 63 to move in the protective groove 24.

[0047] Embodiment 2;

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

[0049] Among them, when lifting a container, the laser sensor 61 emits laser light towards the light blocking plate 63, measures the distance between the luffing trolley 31 and the tower cap 1, and transmits the data into the PLC control box 11 through an electrical signal. At the same time, when the lifting hook 33 lifts the container, the weight of the container is transmitted to the pressure sensor 64 through the rotating shaft of the lifting pulley 32. The pressure sensor 64 transmits the weight data of the container into the PLC control box 11 through an electrical signal. The PLC control box 11 calculates the moment at this time based on the obtained data, thereby monitoring the moment of the crane in real time. When the moment reaches the threshold value that requires an alarm, the PLC control box 11 activates the buzzer 12 to give an alarm. At the same time, an electrical signal is sent to the winding motor 44 and the electric push rod 58 to control the winding motor 44 to only rotate in the reverse direction, and the electric push rod 58 is activated at the same time to enable the limiting component 5 to limit the drum 42. After the lifted container is lowered, the PLC control box 11 cancels the alarm of the buzzer 12. After the lifted container is placed back on the ground, the PLC control box 11 sends an electrical signal to the winding motor 44 and the electric push rod 58 again, enabling the winding motor 44 to drive the drum 42 to rotate forward again, and at the same time the electric push rod 58 lifts the pressing plate 55 to release the restriction on the drum 42.

[0050] The present invention also provides an alarm method, which uses a moment monitoring and alarm device for a tower crane. The specific steps are as follows:

[0051] First, the luffing trolley 31 of the luffing mechanism 3 moves the lifting hook 33 above the container. After the lifting hook 33 hooks the container, the container is lifted. During the process of lifting the container, the moment monitoring component 6 monitors the moment state in real time. When the moment reaches the threshold value, the moment monitoring component 6 issues an alarm and stops the movement of the luffing trolley 31. At the same time, the limiting component 5 drives the pressing plate 55 to fall onto the limiting shaft 53, restricting the drum 42 to only rotate in the reverse direction and not in the forward direction, so as to cooperate with the winding motor 44 to drive the luffing trolley 31 to approach the tower cap 1, reduce the amplitude and lower the moment, thereby canceling the alarm. After the alarm is canceled, the operator slowly places the lifted container back on the ground. At this time, the limiting component 5 lifts the pressing plate 55 to release the restriction on the drum 42.

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

Claims

1. A moment monitoring and alarming device for a tower crane, comprising a tower head and a boom connected to the tower head, characterized in that: A luffing mechanism, a limiting component, and a torque monitoring component are provided on the tower cap. The luffing mechanism includes a luffing trolley and a winding component. The luffing trolley is installed on the boom. A lifting hook is connected below the luffing trolley. The winding component includes a mounting seat and a drum. The mounting seat is installed at one end of the boom close to the tower cap. The drum is connected to the mounting seat. A traction steel cable is wound around the drum. The traction steel cable is connected to the luffing trolley. When the drum rotates, the luffing trolley is pulled by the traction steel cable to move horizontally on the boom. The limiting component includes a mounting box. A transmission shaft, a limiting shaft, and a pressing plate are sequentially arranged in the mounting box. The transmission shaft is connected to the drum. The limiting shaft is connected to the transmission shaft. The pressing plate is fitted on the side of the limiting shaft. When the drum rotates, it can drive the transmission shaft and the limiting shaft to rotate in sequence. When the torque is overloaded, the pressing plate can move down to the limiting shaft to restrict the rotation of the limiting shaft. The restricted limiting shaft thus restricts the rotation of the drum through the transmission shaft. The torque monitoring component includes a laser sensor and a light blocking plate. The laser sensor is installed on the tower cap. The light blocking plate is connected to the luffing trolley.

2. The moment monitoring and alarming device for a tower crane according to claim 1, wherein: The boom is fixedly connected to the tower cap. Guide rails are fixedly connected to both sides of the boom. Pulley groups are fixedly connected to both ends of the boom. A motor seat is fixedly connected to the side of the boom far from the laser sensor. The motor seat is located at one end of the boom close to the tower cap. A protective groove is fixedly installed on the other side of the boom. The laser sensor is located in the protective groove.

3. The moment monitoring and alarming device for a tower crane according to claim 2, characterized in that: The luffing mechanism further includes a lifting pulley. A plurality of rollers are rotatably connected to the luffing trolley. The luffing trolley is slidably installed on the guide rail through the plurality of rollers. The lifting pulley is rotatably connected to the luffing trolley through a rotating shaft. The lifting hook is connected to the lifting pulley through a steel rope.

4. The moment monitoring and alarming device for a tower crane according to claim 3, characterized in that: The mounting seat is fixedly installed on the boom. The drum is rotatably connected to the mounting seat. Reel grooves are formed at both ends of the drum. One traction steel cable is wound in each reel groove. The traction steel cable far from the motor seat bypasses the pulley group close to the tower cap and is fixedly connected to one end of the luffing trolley close to the drum. The other traction steel cable bypasses the pulley group far from the tower cap and is fixedly connected to the end of the luffing trolley far from the drum. A driving gear is coaxially and fixedly connected to one end of the drum. The other end of the drum is coaxially and fixedly connected to the output shaft of a winding motor. The winding motor is fixedly installed on the motor seat.

5. The moment monitoring and alarming device for a tower crane according to claim 4, characterized in that: The mounting box is fixedly mounted on the mounting seat, and a fixing plate and a slide groove are respectively provided in the mounting box. The fixing plate is fixedly mounted on a side of the limiting shaft away from the transmission shaft, and the slide groove is opened on a side of the fixing plate away from the limiting shaft. The transmission shaft and the limiting shaft are rotatably connected in sequence in the mounting box, and a transmission gear and a driven gear are coaxially fixedly connected to the transmission shaft in sequence, and the driven gear is meshed with the driving gear. A plurality of arc-shaped grooves are evenly arranged on the shaft body of the limiting shaft in a circular shape, and a spur gear is coaxially fixedly connected to the end of the limiting shaft, and the spur gear is meshed with the transmission gear.

6. The moment monitoring and alarming device for tower crane according to claim 5, characterized in that: One end of the pressure plate away from the limiting shaft is rotatably connected to the mounting box, and an arc-shaped protrusion is fixedly installed on the bottom of the other end of the pressure plate, and the arc-shaped protrusion corresponds to the arc-shaped groove. Both sides of the pressure plate are slidably installed in the sliding groove through sliders, and a connecting seat is fixedly installed on the top of this end of the pressure plate, and a connecting rod is rotatably installed on the connecting seat, and a connecting rod groove is provided on the connecting rod. Support springs are provided on both sides of the connecting seat, and the two ends of the support spring are fixedly connected to the top of the pressure plate and the bottom of the fixed plate respectively.

7. The moment monitoring and alarming device for a tower crane according to claim 6, characterized in that: The limiting component also includes an electric push rod, which is fixedly mounted on the top of the mounting box, and an output shaft of the electric push rod is slidably connected to the connecting rod groove via a sliding rod.

8. The moment monitoring and alarming device for a tower crane according to claim 7, wherein: The torque monitoring assembly also includes a pressure sensor, which is fixedly installed below the rotating shaft connecting the lifting pulley and the boom trolley. The rotating shaft of the lifting pulley presses on the pressure sensor. The laser sensor is fixedly connected to the tower cap. The light baffle is fixedly connected to the connecting rod. The connecting rod is fixedly connected to the boom trolley. When the boom trolley moves, it drives the light baffle to move in the protective groove.

9. The moment monitoring and alarming device for tower crane according to claim 8, characterized in that: A PLC control box is fixedly connected to the tower cap, and the PLC control box is respectively connected to the laser sensor, the pressure sensor, the winding motor and the electric push rod through electrical signals. A buzzer is fixedly installed on the PLC control box.

10. An alarm method, characterized in that: The tower crane torque monitoring and alarm device according to any one of claims 1 to 9 is used, and the specific steps are as follows: First, the luffing trolley of the luffing mechanism moves the lifting hook to the top of the container, and after the lifting hook hooks the container, the container is lifted. During the process of lifting the container, 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 movement of the luffing trolley. At the same time, the limiting component drives the pressure plate to fall onto the limiting shaft, limiting the reel to only rotate in the reverse direction but not in the forward direction, thereby cooperating with the winding motor to drive the luffing trolley closer to the tower cap, reducing the amplitude and torque, thereby lifting the alarm. After the alarm is lifted, the operator slowly puts the lifted container back to the ground. At this time, the limiting component lifts the pressure plate again to release the restriction on the reel.

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