Winding device for crane

Abstract

The invention relates to the technical field of winding devices, and discloses a winding device for a crane, which comprises a winding device body, the winding device body comprises a rack, pulley blocks arranged on the two sides in the rack, and sliding frames connected to the two ends of the pulley blocks through bearings; the two groups of protection units are respectively positioned on two sides of the rack; and the locking unit comprises locking clamping teeth installed between the two sets of bearing plates, a moving channel is formed between the locking clamping teeth and the first rack plate, and locking clamping plates are arranged on the two sides of the locking clamping teeth correspondingly. The stall driving mechanism takes the centrifugal force of the counterweight ball as core detection power and completely breaks away from the dependence of an electronic sensor, when the sliding frame moves at an overspeed due to hydraulic oil cylinder faults, such as cylinder explosion, fracture or other reasons, the rotating speed of the connecting shaft is synchronously increased, and the counterweight ball slides along the through groove under the action of the centrifugal force to push the clamping block to trigger locking.

Description

Technical Field

[0001] This invention relates to the field of hoisting devices, and more specifically, to a hoisting device for a crane. Background Technology

[0002] In crane hoisting systems, hydraulic cylinders are the core power components driving the sliding frame's translation, and their normal operation directly determines the safety of lifting operations. However, under long-term high-pressure operation, hydraulic cylinders may explode due to seal damage, cylinder wear, or piston rod breakage due to overload, leading to the sliding frame losing control and stalling.

[0003] Existing stall detection systems mostly rely on hydraulic sensors to monitor the extension and retraction speed of hydraulic cylinders or system pressure. When a hydraulic cylinder bursts or breaks, the hydraulic circuit pressure becomes instantly unbalanced, causing sensor signals to distort or be interrupted, making it impossible to identify the runaway state of the steerable frame. Traditional locking devices rely on hydraulic or electric drives. When a hydraulic cylinder bursts along with a loss of hydraulic system pressure, or in the event of an emergency power outage, the locking mechanism loses its power source and cannot trigger the brakes. The steerable frame then moves rapidly under the tension of the lifting ropes or the weight of the load, directly causing the hook to rise and fall at excessive speed, resulting in equipment damage or personal injury. Summary of the Invention

[0004] This invention provides a hoisting device for cranes, which solves the technical problem in related technologies where, when a hydraulic cylinder bursts and the hydraulic system loses pressure, or in the event of an emergency power outage, the locking mechanism loses its power source and cannot trigger the brake. As a result, the sliding frame moves rapidly under the tension of the lifting rope or the weight of the load, directly causing the hook to lift and lower at excessive speed, resulting in the load falling and causing equipment damage or personal injury.

[0005] The present invention provides a hoisting device for a crane, comprising a hoisting device body, the hoisting device body including a frame, pulley blocks disposed on both sides inside the frame, and sliding frames connected to both ends of the pulley blocks by bearings; and hydraulic cylinders corresponding to the number of sliding frames, wherein the telescopic ends of the hydraulic cylinders are rotatably connected to the sliding frames by bearings. At least two sets of protection units are provided, with the two sets of protection units located on both sides of the frame, and each protection unit corresponds to one of the sliding frames on both sides. Each protection unit includes two sets of mounting brackets installed on the frame, and a fixing plate disposed below the frame. A first rack plate is disposed below the fixing plate, and bearing plates are installed on both the upper and lower sides of the first rack plate. A first gear is meshed on the first rack plate, and a connecting shaft is installed on the first gear.

[0006] The locking unit includes locking teeth installed between two sets of bearing plates, with a moving channel formed between the locking teeth and the first rack plate. Locking plates are provided on both sides of the locking teeth. A support frame is provided between the locking plates, and two sets of support plates are respectively installed on both sides of the support frame. The support plates abut against the locking plates. A first tilting block is installed on the support frame, and a second tilting block is provided on the first tilting block. The second tilting block is connected to the connecting shaft through a stall drive mechanism.

[0007] As a further optimization of the present invention, the mounting bracket and the fixing plate are fixedly connected, a guide post is installed between the two sets of mounting brackets, and a guide sleeve is slidably connected to the outside of the guide post, and the guide sleeve is fixedly connected to the sliding bracket.

[0008] As a further optimization of the present invention, limit posts are installed on both sides of the fixing plate, and the limit posts are slidably connected to the locking plate. Second springs are provided on both sides of the outer side of the limit posts.

[0009] As a further optimization of the present invention, the two sides of the support frame are slidably connected with limit rods, and the limit rods are fixedly connected to the fixing plate.

[0010] As a further optimization of the present invention, the stall drive mechanism includes a connecting disc mounted on the connecting shaft, and a second gear is provided on the outside of the connecting disc. The second gear is rotatably connected to the connecting frame through a bearing. A second rack plate is meshed on the second gear, and a connecting plate is mounted on the second rack plate.

[0011] As a further optimization of the present invention, the interior of the connecting disk is provided with multiple sets of movable grooves in a ring shape, and a locking block is slidably connected inside the movable groove. A first spring is provided outside the locking block, one end of the first spring is fixedly connected to the movable groove, and the other end of the first spring is fixedly connected to the locking block.

[0012] As a further optimization of the present invention, a support frame is also installed on the fixed plate, and a slide rail is provided on the support frame. A slider is slidably connected inside the slide rail, and the slider is fixedly connected to the connecting plate.

[0013] As a further optimization of the present invention, the interior of the second gear is provided with multiple sets of slots in a ring shape, and the number of slots and the number of slots are the same.

[0014] As a further optimization of the present invention, the movable groove is further provided with a through groove, and a counterweight ball is provided inside the through groove.

[0015] As a further optimization of the present invention, a magnetic patch is provided at the end of the through groove away from the movable groove, which enhances the stability of the counterweight ball under normal conditions through magnetic field force.

[0016] The beneficial effects of this invention are as follows: This invention uses the centrifugal force of the counterweight ball as the core power detection mechanism through a stall drive mechanism, completely eliminating reliance on electronic sensors. When the sliding frame moves at excessive speed due to hydraulic cylinder failure, such as cylinder explosion, breakage, or other reasons, the connecting shaft speed increases synchronously, and the counterweight ball slides along the through groove under the action of centrifugal force, pushing the locking block to trigger locking. In the locking unit, the support frame normally abuts against the locking plate through the support plate, ensuring that the first rack plate can slide freely without affecting the normal operation of the hoisting device; when stall is triggered, the support frame moves down, causing the support plate to disengage from the abutment, and the locking plate instantly engages under the action of spring force. Attached Figure Description

[0017] Figure 1 This is a three-dimensional structural schematic diagram of the present invention; Figure 2 This is a partial three-dimensional structural diagram of the present invention. Figure 1 ; Figure 3 This is a partial three-dimensional structural diagram of the present invention. Figure 2 ; Figure 4 This is a partial three-dimensional structural diagram of the protection unit and locking unit of the present invention; Figure 5 This is a partial three-dimensional structural diagram of the stall drive mechanism of the present invention; Figure 6 This is a three-dimensional structural diagram of the stall drive mechanism of the present invention; Figure 7 This is a three-dimensional structural diagram of the locking unit of the present invention; Figure 8 This is a partial three-dimensional structural diagram of the stall drive mechanism and locking unit of the present invention.

[0018] In the diagram: 100, hoisting device body; 110, frame; 120, pulley block; 130, sliding frame; 140, hydraulic cylinder; 150, lifting rope; 160, hook; 200, protection unit; 210, mounting bracket; 220, fixing plate; 230, guide column; 240, guide sleeve; 250, first rack plate; 260, bearing plate; 270, first gear; 280, connecting shaft; 281, connecting plate; 282, second gear; 283, second rack plate; 284, connecting plate 285. Support frame; 286. Slide rail; 287. Slider; 288. Movable groove; 289. Locking block; 2810. First spring; 2811. Slot; 2812. Through groove; 2813. Counterweight ball; 290. Connecting frame; 300. Locking unit; 310. Locking tooth; 320. Locking plate; 330. Limiting post; 340. Second spring; 350. Support frame; 360. Support plate; 370. Limiting rod; 380. First tilting block; 390. Second tilting block. Detailed Implementation

[0019] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and implement the subject matter described herein, and changes may be made to the function and arrangement of the elements discussed without departing from the scope of this specification. Various processes or components may be omitted, substituted, or added as needed in the examples. Furthermore, features described in some examples may be combined in other examples.

[0020] According to the appendix Figure 1 As shown, a hoisting device for a crane includes a hoisting device body 100, which includes a frame 110. Both sides of the frame 110 are provided with pulley blocks 120, and both ends of the pulley blocks 120 are rotatably connected to sliding frames 130 via bearings. The frame 110 is equipped with hydraulic cylinders 140 corresponding to the number of sliding frames 130, and the extension and retraction ends of the hydraulic cylinders 140 are rotatably connected to the sliding frames 130 via bearings. Two sets of lifting ropes 150 are wound together on the two sets of pulley blocks 120. A hook 160 is provided below the frame 110, and the ends of the two sets of lifting ropes 150 away from the pulley blocks 120 are fixedly connected to the hook 160.

[0021] It should be understood that during operation, the hydraulic cylinder 140 serves as the power source, and its extension and retraction movements drive the sliding frame 130 to move along the inner side of the frame 110 via bearing transmission.

[0022] The translation of the sliding frame 130 directly drives the pulley blocks 120 to move synchronously, forming a relative approaching or moving away movement of the two pulley blocks 120. When the hydraulic cylinder 140 extends, the sliding frame 130 drives the pulley blocks 120 to separate to both sides, increasing the distance; when the hydraulic cylinder 140 retracts, the sliding frame 130 pulls the pulley blocks 120 closer to the center, decreasing the distance.

[0023] When the gap between the pulley blocks 120 increases, the two sets of lifting ropes 150 are spread apart to both sides, and the contact point of the rope on the surface of the pulley block 120 moves outward, which causes the effective rope length between the hook 160 and the pulley block 120 to shorten, and the hook 160 is lifted upward under the action of tension.

[0024] When the gap between pulley blocks 120 decreases, the lifting rope 150 naturally loosens as the pulley blocks 120 move closer together, the effective rope length increases, and the hook 160 sinks downward under the action of gravity.

[0025] Two sets of lifting ropes 150 are symmetrically distributed on both sides of the hook 160, maintaining balanced force during lifting and lowering to prevent the hook 160 from swaying due to force on one side.

[0026] According to the appendix Figure 1 As shown, there are at least two sets of protection units 200, which are located on both sides of the frame 110, and each protection unit 200 corresponds to one of the sliding frames 130 on both sides.

[0027] In one embodiment, according to the appendix Figure 2 Appendix Figure 3 and attached Figure 4 As shown, the protection unit 200 includes two sets of mounting brackets 210 mounted on the frame 110, and a fixing plate 220 disposed below the frame 110. The mounting brackets 210 and the fixing plate 220 are fixedly connected. A guide post 230 is installed between the two sets of mounting brackets 210, and a guide sleeve 240 is slidably connected to the outside of the guide post 230. The guide sleeve 240 is fixedly connected to the sliding frame 130. A first rack plate 250 is disposed below the fixing plate 220, and a bearing plate 260 is installed on both the upper and lower sides of the first rack plate 250. A set of bearing plates 260 at the top is fixedly connected to the guide sleeve 240. A first gear 270 is meshed on the first rack plate 250, and a connecting shaft 280 is mounted on the first gear 270. A connecting frame 290 is connected to the connecting shaft 280 by a bearing, and the connecting frame 290 is fixedly connected to the fixing plate 220.

[0028] It is important to understand that when the sliding frame 130 moves, the guide sleeve 240, which is fixedly connected to it, slides along the guide post 230, forming a rigid guiding constraint to ensure that the sliding frame 130 only translates along a preset trajectory, preventing the pulley block 120 from deviating. The guide sleeve 240 drives the first rack plate 250 to move synchronously via the bearing plate 260. The first rack plate 250 meshes with the first gear 270, causing the first gear 270 to rotate, which in turn drives the connecting shaft 280 to rotate.

[0029] According to the appendix Figure 3 and attached Figure 7 As shown, the locking unit 300 includes locking teeth 310 installed between two sets of bearing plates 260. A moving channel is formed between the locking teeth 310 and the first rack plate 250. Locking plates 320 are provided on both sides of the locking teeth 310.

[0030] Specifically, the locking teeth 310 and the first rack plate 250 form a moving channel, which provides space for the normal translation of the first rack plate 250 and ensures that the sliding frame 130 can move freely under rated working conditions. Secondly, through the cooperation of the locking plates 320 on both sides and the locking teeth 310, the locking action can be directly applied to the first rack plate 250, realizing the function switching between normal movement and emergency locking.

[0031] Furthermore, limit posts 330 are installed on both sides of the fixing plate 220, and the limit posts 330 are slidably connected to the locking plate 320. A second spring 340 is provided on both sides of the outside of the limit posts 330. One end of the second spring 340 is fixedly connected to the fixing plate 220, and the other end of the second spring 340 is fixedly connected to the locking plate 320.

[0032] It should be noted that the pre-compression design of the second spring 340 provides the reset power for the locking plate 320. Under normal conditions, the spring is compressed to store potential energy. When it stalls, it releases elastic force to push the locking plate 320 to move quickly inward, so as to achieve precise engagement with the locking tooth 310. At the same time, it can assist the locking plate 320 to return to the initial position during reset, thus balancing locking efficiency and reset convenience.

[0033] According to the appendix Figure 4 and attached Figure 8 As shown, in one embodiment, a support frame 350 is provided between the locking plates 320, and two sets of support plates 360 are respectively installed on both sides of the support frame 350, with the support plates 360 abutting against the locking plates 320.

[0034] It is important to understand that during normal operation, the support plate 360 ​​overcomes the elastic force of the second spring 340 to push the locking plate 320 outward, ensuring that it maintains a gap with the locking teeth 310 and does not affect the movement of the first rack plate 250. When stalling, the support frame 350 moves downward, the support plate 360 ​​disengages from the contact, and the constraint is released, allowing the locking plate 320 to quickly engage under the action of the spring force, thus achieving precise control of state switching.

[0035] Furthermore, the support frame 350 is slidably connected to the two sides of the limiting rod 370, and the limiting rod 370 is fixedly connected to the fixing plate 220, thereby ensuring that the support frame 350 can slide up and down along the limiting rod 370, and avoiding the failure of the support plate 360 ​​to abut against the locking plate 320 due to lateral displacement.

[0036] According to the appendix Figure 5 and attached Figure 8 As shown, in one embodiment, a first tilting block 380 is mounted on the support frame 350, and a second tilting block 390 is provided on the first tilting block 380. The second tilting block 390 is connected to the connecting shaft 280 through a stall drive mechanism.

[0037] Specifically, the first tilting block 380 and the second tilting block 390 achieve force direction conversion through inclined surface contact, converting the power transmitted by the stall drive mechanism into the vertical downward movement of the support frame 350, efficiently connecting the stall detection signal and the locking execution action, and ensuring the sensitivity of locking triggering.

[0038] It is important to understand that during normal operation of the hoisting device, the connecting shaft 280 rotates smoothly, the stall drive mechanism is not activated, the second tilting block 390 remains separated from the first tilting block 380, and the support frame 350 is in a high position under the constraint of the limit rod 370. At this time, the support plates 360 on both sides of the support frame 350 are in close contact with the locking plate 320, overcoming the preload of the second spring 340 and pushing the locking plate 320 outward, so that the locking plate 320 and the locking tooth 310 maintain a gap, and the first rack plate 250 can slide freely along the moving channel without affecting the normal translation of the sliding frame 130.

[0039] When the hoisting device stalls, such as when the sliding frame 130 moves too fast, causing the connecting shaft 280 to rotate too high, the stall drive mechanism is activated, driving the second tilting block 390 to move towards the first tilting block 380. Through the force transmission of the inclined surface contact, the second tilting block 390 pushes the first tilting block 380 to move vertically downward, pushing the support frame 350 to slide downward along the limit rod 370. As the support frame 350 moves downward, the support plate 360 ​​simultaneously disengages from the locking plate 320, releasing the outer constraint on the locking plate 320. At this time, the pre-compressed second spring 340 releases its elastic potential energy, pushing the locking plate 320 to move rapidly inward along the limiting post 330, ultimately forming a tight engagement with the locking teeth 310. Because the locking teeth 310 are compatible with the tooth profile of the first rack plate 250, the engagement directly blocks the movement of the first rack plate 250, transmitting the movement to the sliding frame 130 through the guide sleeve 240, forcing the pulley block 120 to stop its displacement and preventing the hook 160 from going out of control.

[0040] After troubleshooting, the stall drive mechanism can be manually reset, the locking unit 300 will be restored to the restraint state, and the winch can operate normally.

[0041] According to the appendix Figure 4 Appendix Figure 5 and attached Figure 6 As shown, in one embodiment, the core function of the stall drive mechanism is to detect changes in the rotational speed of the connecting shaft 280 and implement different action logics in normal operation and stall state. The stall drive mechanism includes a connecting disk 281 mounted on the connecting shaft 280, and a second gear 282 is provided on the outside of the connecting disk 281. The second gear 282 is rotatably connected to the connecting frame 290 through a bearing. A second rack plate 283 is meshed on the second gear 282, and a connecting plate 284 is mounted on the second rack plate 283.

[0042] It should be noted that the connecting plate 281 rotates synchronously with the connecting shaft 280, and the second gear 282 rotates independently through the bearing. The meshing structure between the second gear 282 and the second rack plate 283 accurately converts the rotational motion of the connecting shaft 280 into the linear motion of the second rack plate 283. The connecting plate 284 can stably transmit this linear motion to the subsequent execution components.

[0043] The fixed plate 220 is also equipped with a support frame 285, and the support frame 285 is provided with a slide rail 286. The slide rail 286 is slidably connected to a slider 287, and the slider 287 is fixedly connected to the connecting plate 284.

[0044] It is important to understand that the slide 286 and the slider 287 form a guiding constraint to ensure that the second rack plate 283 always maintains the correct meshing position with the second gear 282 during linear motion, thus avoiding transmission jamming or tooth dislodging caused by rack misalignment.

[0045] Furthermore, the interior of the connecting plate 281 is provided with multiple sets of movable grooves 288 in a ring shape, and a locking block 289 is slidably connected inside the movable groove 288. A first spring 2810 is provided on the outside of the locking block 289. One end of the first spring 2810 is fixedly connected to the movable groove 288, and the other end of the first spring 2810 is fixedly connected to the locking block 289.

[0046] Specifically, the movable groove 288 provides sliding space for the locking block 289. When stalling, the locking block 289 can move outward along the groove to overcome the spring force and embed into the locking groove 2811 to achieve linkage.

[0047] Furthermore, the interior of the second gear 282 has multiple sets of slots 2811 arranged in a ring shape, and the number of slots 289 and slots 2811 are the same.

[0048] It is important to understand that the number of the ring-shaped slots 2811 and the number of the blocks 289 are matched to ensure that multiple blocks 289 can be simultaneously inserted into the corresponding slots 2811 when stalling, making the torque transmission between the connecting disc 281 and the second gear 282 more uniform.

[0049] According to the appendix Figure 6 As shown, in one embodiment, the movable groove 288 is further provided with a through groove 2812, and a counterweight ball 2813 is provided inside the through groove 2812.

[0050] It should be noted that under normal rotation speed, the centrifugal force is small and the counterweight ball 2813 does not push the locking block 289; when the rotation speed exceeds the limit, the centrifugal force increases sharply, and the counterweight ball 2813 slides outward along the through groove 2812 and pushes the locking block 289 to move.

[0051] A magnetic patch is provided at the end of the through groove 2812 away from the movable groove 288, which enhances the stability of the counterweight ball 2813 under normal conditions through magnetic field force. Under normal conditions, the counterweight ball 2813 is in full contact with the patch, and the magnetic force is strongest; when it slides outward under the action of centrifugal force, it leaves the coverage area of ​​the patch, and the magnetic force decays instantly, ensuring smooth throwing out.

[0052] It is important to understand that when the hoisting device is working normally, the sliding frame 130 moves smoothly, the connecting shaft 280 rotates at its rated speed, driving the connecting disc 281 to rotate synchronously. The centrifugal force on the counterweight ball 2813 is small, and under the magnetic attraction of the magnetic patch, it remains inside the through slot 2812. Furthermore, under the preload of the first spring 2810, the locking block 289 is inside the movable slot 288 and does not mesh with the locking slot 2811 of the second gear 282. Because the second gear 282 is not driven by the connecting disc 281, it remains stationary, and its meshing second rack plate 283 has no displacement. The slider 287 remains stationary within the slide rail 286. Finally, the second tilting block 390 remains separated from the first tilting block 380, the locking unit 300 is not activated, and the sliding frame 130 moves normally.

[0053] When the hoisting device stalls, such as when the sliding frame 130 moves at excessive speed, causing the connecting shaft 280 to rotate too high, the counterweight ball 2813, due to a sharp increase in centrifugal force, slides outward along the through groove 2812, pushing the locking block 289 in the movable groove 288 to overcome the elastic force of the first spring 2810 and move outward from the connecting plate 281. The end of the locking block 289 is embedded in the slot 2811 of the second gear 282, forming a rigid connection between the connecting plate 281 and the second gear 282. The rotational force of the connecting shaft 280 is transmitted to the second gear 282 through the locking block 289 and the slot 2811, driving the second gear 282 to rotate synchronously.

[0054] The second gear 282 meshes with the second rack plate 283, causing the rack plate to move linearly. The connecting plate 284 moves synchronously with the rack plate, and the slider 287 slides along the slide rail 286. The displacement of the second rack plate 283 drives the second inclined block 390 to move closer to the first inclined block 380 through mechanical transmission. The inclined surface contacts and pushes the first inclined block 380 downward, thereby triggering the locking unit 300 to act, ultimately achieving forced locking of the sliding frame 130.

[0055] After troubleshooting, manually reduce the rotation speed of the connecting shaft 280. The centrifugal force of the counterweight ball 2813 decreases, and the locking block 289 retracts into the movable groove 288 under the action of the first spring 2810, separating from the groove 2811. The second gear 282 returns to its free state. Reverse drive the connecting shaft 280 or manually reset the second rack plate 283 to separate the second tilting block 390 from the first tilting block 380. The locking unit 300 returns to its initial state, and the hoisting device operates normally.

[0056] The embodiments of this specific implementation have been described above. However, this embodiment is not limited to the specific implementation described above. The specific implementation described above is merely illustrative and not restrictive. Those skilled in the art can make many other forms based on the guidance of this embodiment, all of which are within the protection scope of this embodiment.

Claims

1. A hoisting device for a crane, characterized in that, include: The winch body includes a frame, pulley blocks (pulley blocks) disposed on both sides inside the frame, and sliding frames connected to both ends of the pulley blocks by bearings; and hydraulic cylinders corresponding to the number of sliding frames, wherein the telescopic ends of the hydraulic cylinders are rotatably connected to the sliding frames by bearings. At least two sets of protection units are provided, with the two sets of protection units located on both sides of the frame, and each protection unit corresponds to one of the sliding frames on both sides. The protection unit includes two sets of mounting brackets installed on the frame, and a fixing plate disposed below the frame. A first rack plate is disposed below the fixing plate. Bearing plates are installed on both the upper and lower sides of the first rack plate. A first gear is meshed on the first rack plate, and a connecting shaft is installed on the first gear. The locking unit includes locking teeth installed between the two sets of bearing plates, the locking teeth forming a moving channel with the first rack plate, and locking plates provided on both sides of the locking teeth; A support frame is provided between the locking plates, and two sets of support plates are installed on both sides of the support frame, with the support plates abutting against the locking plates. A first tilting block is installed on the support frame, and a second tilting block is provided on the first tilting block. The second tilting block is connected to the connecting shaft through a stall drive mechanism.

2. A hoisting device for a crane according to claim 1, characterized in that, The mounting bracket and the fixing plate are fixedly connected. A guide post is installed between the two sets of mounting brackets, and a guide sleeve is slidably connected to the outside of the guide post. The guide sleeve is fixedly connected to the sliding bracket.

3. A hoisting device for a crane according to claim 1, characterized in that, Limiting posts are installed on both sides of the fixing plate, and the limiting posts are slidably connected to the locking plate. Second springs are provided on both sides of the outer side of the limiting posts.

4. A hoisting device for a crane according to claim 1, characterized in that, Limiting rods are slidably connected to both sides of the support frame, and the limiting rods are fixedly connected to the fixing plate.

5. A hoisting device for a crane according to claim 1, characterized in that, The stall drive mechanism includes a connecting disc mounted on the connecting shaft, and a second gear is provided on the outside of the connecting disc. The second gear is rotatably connected to the connecting frame through a bearing. A second rack plate is meshed on the second gear, and a connecting plate is mounted on the second rack plate.

6. A hoisting device for a crane according to claim 5, characterized in that, The connecting disc has multiple sets of movable grooves arranged in a ring shape inside, and a locking block is slidably connected inside the movable groove. A first spring is provided on the outside of the locking block. One end of the first spring is fixedly connected to the movable groove, and the other end of the first spring is fixedly connected to the locking block.

7. A hoisting device for a crane according to claim 5, characterized in that, The fixed plate is also equipped with a support frame, and the support frame has a slide rail. A slider is slidably connected inside the slide rail, and the slider is fixedly connected to the connecting plate.

8. A hoisting device for a crane according to claim 6, characterized in that, The second gear has multiple sets of slots arranged in a ring inside, and the number of slots and the number of the locking blocks are the same.

9. A hoisting device for a crane according to claim 6, characterized in that, The movable groove is also provided with a through groove, and a counterweight ball is provided inside the through groove.

10. A hoisting device for a crane according to claim 9, characterized in that, A magnetic patch is provided at the end of the through groove away from the movable groove, which enhances the stability of the counterweight ball under normal conditions through magnetic field force.

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