Spent fuel storage and transportation hanging basket
By designing a spent fuel storage and transportation hanging basket including buffer seat assembly, bottom plate, storage casing, reinforced bracket plate, top bracket plate and hoisting assembly, the needs of continuous operation and multiple sets of components storage and transportation functions in spent fuel storage and transportation are solved, and efficient and stable storage and transportation of spent fuel components are achieved, and safety and transportation efficiency are improved.
Patent Information
- Application Number
- CN202510374026.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-27
- Publication Date
- 2025-06-13
AI Technical Summary
The prior art is difficult to meet the needs of continuous operation and storage and transportation functions of multiple sets of spent fuel components during spent fuel storage and transportation, and the stability and transport efficiency of spent fuel storage and transportation baskets are insufficient.
A spent fuel storage and transportation hanging basket is designed, including buffer seat assembly, bottom plate, storage sleeve, reinforced bracket plate, top bracket plate and hoisting assembly. Through the design and combination of these components, stable storage and rapid transport of spent fuel components are achieved.
The design combines the transport of spent fuel components with storage functions, improves the stability and transport efficiency of the entire device, reduces the water injection volume and factory construction costs, and enhances safety.
Smart Images
Figure CN120148924A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of spent fuel assembly storage and transportation, and specifically to a spent fuel storage and transportation hanging basket. Background Technique
[0002] Spent fuel refers to nuclear fuel that is no longer suitable for continued power generation after being used in a nuclear reactor due to the accumulation of radionuclides and the generation of fission products. Although called "spent fuel", these materials still contain a large amount of fissile materials such as unburned uranium and plutonium, and have potential reuse value.
[0003] In the prior art, under the current circumstances, China needs to have a complete nuclear fuel cycle system. At present, a policy of closed-loop recycling of nuclear fuel has been formulated, and the technical route of reprocessing spent fuel to recover uranium and plutonium is adopted. As a key equipment in the storage and transportation process of spent fuel, the successful development of the spent fuel storage and transportation hanging basket directly affects whether the hanging basket process can be used for the storage and transportation of spent fuel. Therefore, according to the technological requirements of spent fuel reception, storage, and transportation in large reprocessing plants, the necessity of developing a hanging basket that can meet the functions of continuous operation, storing and transporting multiple groups of spent fuel assemblies at one time is prominent. For this reason, the present invention proposes a spent fuel storage and transportation hanging basket to solve the above problems. Summary of the Invention
[0004] The purpose of the present invention is to provide a spent fuel storage and transportation hanging basket to solve the problems raised in the above background technique.
[0005] To achieve the above purpose, the present invention provides the following technical solution: A spent fuel storage and transportation hanging basket, comprising: a buffer seat assembly, a bottom plate is arranged on the upper side of the buffer seat assembly, storage sleeves are arranged in a rectangular array on the upper surface of the bottom plate, and water inlet holes are penetrated and opened between the bottom of the storage sleeves and the bottom plate; A reinforcing support plate is sleeved in the middle of the storage sleeve and is in clearance fit with the reinforcing support plate. A top support plate is sleeved on the top of the storage sleeve and abuts against the inner wall of the top support plate. A hole plate is detachably installed in the top support plate, and lifting assemblies are arranged at the four corners of the upper surface of the top support plate; The four corners of the outer side walls of the bottom plate, the reinforcing support plate, and the top support plate are fixedly connected to the support steel plates through bolts.
[0006] Preferably, the buffer seat assembly includes a limit frame, which is slidably connected to both the bottom plate and the support steel plate. Drainage holes are arranged in a rectangular array on the outer side wall of the limit frame, and buffers are arranged in a rectangular array on the inner side wall of the limit frame.
[0007] Preferably, one end of the buffer is fixedly connected to the inner side wall of the limit frame, the other end of the buffer is rotatably connected to one end of a connecting rod through a pin shaft, and the other end of the connecting rod is rotated through a pin shaft with a connecting seat.
[0008] Preferably, the upper surface of the connecting seat is fixedly connected to the lower surface of the bottom plate. A damper is arranged on one side of the connecting seat, and the damper is fixedly installed between the inner wall of the bottom of the limiting frame and the lower surface of the bottom plate.
[0009] Preferably, the bottom plate is fixedly welded to the bottom of the storage sleeve. A flexible buffer layer is arranged between the gaps of the storage sleeve and the reinforcing support plate. Cavities are formed at the four corners of the inner side wall of the top support plate, and a pressing plate is installed on one side of the cavity.
[0010] Preferably, one end of the pressing plate is fixedly connected to the bottom of the spring, and the top of the spring is fixedly connected to the top of the inner wall of the cavity. The lower surface of the pressing plate abuts against the upper surface of the orifice plate, and the lower surface of the pressing plate abuts against the top of the storage sleeve. A stainless steel pipe is fixedly installed inside the storage sleeve, and a titanium-based composite plate is fixedly connected to the outer circumferential surface of the stainless steel pipe. Through holes are formed on the surfaces of the reinforcing support plate and the top support plate.
[0011] Preferably, the hoisting assembly includes a mounting plate. Reinforcing rods are fixedly sleeved at the four corners of the mounting plate. The reinforcing rods penetrate and are fixed between the reinforcing support plate and the top support plate, and the bottom is fixedly welded to the upper surface of the bottom plate.
[0012] Preferably, a limiting sleeve is fixedly connected to the upper surface of the mounting plate. An installation shell is fixedly connected to the lower surface of the mounting plate. A limiting piece is sleeved at the bottom of the installation shell and fixedly connected to the limiting piece. A limiting column is arranged between the limiting sleeve and the installation shell. The limiting column is sleeved in the middle of the mounting plate and fixedly connected to the mounting plate. The bottom of the limiting column is fixedly connected to the top of the connecting column.
[0013] Preferably, inclined surfaces are symmetrically formed on both sides of the bottom of the connecting column. The inclined surfaces are slidably connected to one end of the hook plate. The other end of the hook plate is fixedly connected to a hook block. There are two hook plates arranged in a cross pattern. A grasping rod is installed between the hook plates. The grasping rod is rotatably connected to the middle of the hook plate through a limiting pin. Limiting rods are fixedly sleeved at one ends of the two hook plates close to the connecting column. The two limiting rods are fixedly connected through a tension spring. The grasping rod is slidably sleeved between the limiting sleeve, the limiting column, and the connecting column.
[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The present invention combines the functions of transporting and storing spent fuel assemblies. The loading and unloading of the spent fuel assemblies in the hanging basket are both completed in the discharge pool. In the storage pool, only the hanging basket needs to be transported (the spent fuel pool includes a discharge pool and a storage pool). At the same time, the stability of the whole device during placement is improved by setting the buffer seat assembly. Through the provided hoisting assembly, the rapid transportation of the whole device and subsequent transportation are facilitated, the transportation time is reduced, the transportation efficiency is improved, the operating elevation of the hanging basket and the elevation of the pool surface of the pool are reduced, the safety is improved while reducing the water injection volume in the spent fuel pool, the load on the pool bottom is reduced, and the construction cost of the plant is reduced.
[0015] 2. The storage sleeve is limited and fixed by the provided bottom plate, reinforcement support plate, and top support plate, thereby enhancing the stability of the entire fixed frame. Then, support steel plates are fixedly installed at the four corners of the outer side walls of the bottom plate, reinforcement support plate, and top support plate through bolts, further improving the overall strength and stiffness of the entire fixed frame. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 is a schematic diagram of the overall structure of the present invention; Figure 2 is a top view schematic diagram of the overall structure of the present invention; Figure 3 is a bottom view schematic diagram of the internal structure of the present invention; Figure 4 For the present invention Figure 3 is an enlarged schematic diagram of the structure at A in; Figure 5 is a top view schematic diagram of the internal structure of the present invention; Figure 6 For the present invention Figure 5 is an enlarged schematic diagram of the structure at B in.
[0017] In the figure: 1, buffer seat assembly; 2, bottom plate; 3, storage sleeve; 4, water inlet hole; 5, reinforcement support plate; 6, top support plate; 7, orifice plate; 8, hoisting assembly; 9, support steel plate; 10, bolt; 11, limiting frame; 12, drainage hole; 13, buffer; 14, pin shaft; 15, connecting rod; 16, connecting seat; 17, damper; 18, flexible buffer layer; 19, cavity; 20, pressing piece; 21, spring; 22, stainless steel pipe; 23, titanium-based composite plate; 24, through hole; 25, mounting plate; 26, reinforcing rod; 27, limiting sleeve; 28, mounting shell; 29, limiting piece; 30, limiting column; 31, connecting column; 32, inclined surface; 33, hook plate; 34, hook block; 35, grasping rod; 36, limiting rod; 37, tension spring. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0018] In order to clearly and completely describe the objectives, technical solutions of the present invention, and make the advantages more clearly understood, the following further elaborates on the embodiments of the present invention with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are some, but not all, of the embodiments of the present invention, and are only used to explain the embodiments of the present invention, not to limit the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.
[0019] Embodiment 1: Please refer to Figures 1 to 6, the present invention provides a technical solution: a spent fuel storage and transportation hanging basket, comprising: a buffer seat assembly 1, the buffer seat assembly 1 buffers the entire fixed frame during placement, a bottom plate 2 is arranged on the upper side of the buffer seat assembly 1, storage sleeves 3 are arranged in a rectangular array on the upper surface of the bottom plate 2, the storage sleeves 3 facilitate the placement of spent fuel, a water inlet hole 4 is penetrated and opened between the bottom of the storage sleeve 3 and the bottom plate 2, a reinforcement support plate 5 is sleeved in the middle of the storage sleeve 3 and is in clearance fit with the reinforcement support plate 5, the reinforcement support plate 5 reinforces the entire frame and improves the strength of the entire fixed frame, a top support plate 6 is sleeved on the top of the storage sleeve 3 and abuts against the inner wall of the top support plate 6, the four corners of the inner side of the top of the top support plate 6 are designed with rounded corners, thus facilitating the guiding structure for the insertion of the spent fuel assembly, a hole plate 7 is detachably installed in the top support plate 6, and lifting assemblies 8 are arranged at the four corners of the upper surface of the top support plate 6. Through the arrangement of the lifting assemblies 8, the positioning and grasping of an external gripper can be facilitated, and then the entire fixed frame can be transported. The four corners of the outer side walls of the bottom plate 2, the reinforcement support plate 5, and the top support plate 6 are fixedly connected to a support steel plate 9 through bolts 10.
[0020] The bottom plate 2, the reinforcement support plate 5, and the top support plate 6 are provided to limit and fix the storage sleeve 3, thereby improving the stability of the entire fixed frame. Further, by fixedly installing the support steel plate 9 at the four corners of the outer side walls of the bottom plate 2, the reinforcement support plate 5, and the top support plate 6 through bolts 10, the overall strength and stiffness of the entire fixed frame are further improved. The storage sleeve 3 is used for storing spent fuel. Since there is a gap between the storage sleeve 3 and the reinforcement support plate 5, in the event of accidents such as earthquakes and impacts, the storage sleeve 3 may be affected by external forces and shift or vibrate. At this time, the gap decreases, and the storage sleeve 3 contacts the inner wall of the reinforcement support plate 5, providing necessary circumferential support to prevent the storage sleeve 3 from shaking excessively or deviating from its original position, thereby protecting the safety of the spent fuel assembly. By matching the water inlet hole 4 opened at the bottom of the bottom plate 2 and the storage sleeve 3 with the hole plate 7 installed at the top of the storage sleeve 3, the circulation of cooling water can be ensured. At the same time, the setting of the hole plate 7 can prevent the spent fuel assembly from being thrown out during abnormal accidents. The lifting assemblies 8 arranged at the four corners of the top of the top support plate 6 can facilitate the positioning and grasping of an external gripper, and further facilitate the transfer of the entire fixed frame.
[0021] Embodiment 2: On the basis of Embodiment 2, the buffer seat assembly 1 includes a limit frame 11. The limit frame 11 is slidably connected to both the bottom plate 2 and the support steel plate 9. Drainage holes 12 are arranged in a rectangular array on the outer side wall of the limit frame 11, and buffers 13 are arranged in a rectangular array on the inner side wall of the limit frame 11. The limit frame 11 is slidably connected to the peripheral side walls of the bottom plate 2 to limit it. The drainage holes 12 provided on the peripheral side walls of the limit frame 11 facilitate the drainage of cooling water. One end of the buffer 13 is fixedly connected to the inner side wall of the limit frame 11, and the other end of the buffer 13 is rotatably connected to one end of a connecting rod 15 through a pin shaft 14. The other end of the connecting rod 15 is rotated through the pin shaft 14 with a connecting seat 16. The buffer 13 is a component that can be compressed and reset. By providing the buffer 13, the entire fixed frame can be buffered when placed in the storage pool, thereby improving the stability and safety of the entire device. The upper surface of the connecting seat 16 is fixedly connected to the lower surface of the bottom plate 2, and a damper 17 is arranged on one side of the connecting seat 16. The damper 17 is fixedly installed between the inner bottom wall of the limit frame 11 and the lower surface of the bottom plate 2.
[0022] When the spent fuel storage and transportation hanging basket is in place, there is no any unloading connection between it and the steel cladding surface of the storage pool. It only needs to place the spent fuel storage and transportation hanging basket in the storage pool. When placing it, the bottom plate 2 is rotationally connected with one end of the connecting rod 15 through the connection of the connecting seat 16 and the pin shaft 14, so that the other end of the connecting rod 15 laterally pushes the buffer 13, causing the buffer 13 to be compressed. Thus, the bottom plate 2 slides into the interior of the limit frame 11, and then cooperates with the buffering of the damper 17 to realize the shock absorption and buffering of the bottom plate 2, ensuring the stability of the entire fixed frame during the placement process, improving the safety. At the same time, it can also make the entire fixed frame not easily deformed under similar working conditions such as earthquakes, or the spent fuel assembly is still in a subcritical and natural cooling state after deformation.
[0023] Embodiment 3: On the basis of Embodiment 3, the bottom plate 2 is fixedly welded to the bottom of the storage sleeve 3. A flexible buffer layer 18 is provided in the gap between the storage sleeve 3 and the reinforcement support plate 5. Thus, when the storage sleeve 3 is offset or vibrated due to external forces, its outer wall contacts the flexible buffer layer 18, and then it can buffer the storage sleeve 3 and improve the circumferential support under accident conditions. Cavities 19 are opened at the four corners of the inner side wall of the top support plate 6. A pressing piece 20 is installed on one side of the cavity 19. The opening of the cavity 19 facilitates the movement of the pressing piece 20. One end of the pressing piece 20 is fixedly connected to the bottom of a spring 21, and the top of the spring 21 is fixedly connected to the top inner wall of the cavity 19. The lower surface of the pressing piece 20 abuts against the upper surface of the hole plate 7. The hole plate 7 is made of a material with slightly deformable properties, so as to facilitate the placement of the hole plate 7 in the top support plate 6. The lower surface of the pressing piece 20 abuts against the top of the storage sleeve 3. A stainless steel pipe 22 is fixedly installed inside the storage sleeve 3, and a titanium-based composite plate 23 is fixedly connected to the outer circumferential surface of the stainless steel pipe 22. Through holes 24 are opened on the surfaces of the reinforcement support plate 5 and the top support plate 6.
[0024] By pressing the pressing plate 20 upward, while the pressing plate 20 slides in the four-corner cavities 19 of the top support plate 6, the spring 21 is compressed, causing the spring 21 to generate a reverse elastic force. Then, the orifice plate 7 can be placed in the top support plate 6 due to its slightly deformable characteristic. After that, the pressing plate 20 is released and reset under the elastic force of the spring 21, so that the pressing plate 20 presses the orifice plate 7, thus preventing the cooling water from floating it up. Through the several holes opened on the orifice plate 7 and the water inlet holes 4 opened between the bottom plate 2 and the storage sleeve 3, it is beneficial to the circulation of the cooling water. At the same time, through holes 24 are opened on the surfaces of the reinforcement support plate 5 and the top support plate 6, so that both the reinforcement support plate 5 and the top support plate 6 are in a hollowed-out setting, reducing the weight of the entire fixed frame, thereby improving the stability of the entire fixed frame. The stainless steel tube 22 is the actual place for storing spent fuel assemblies, and these assemblies are placed inside the stainless steel tube 22. The function of the titanium-based composite plate 23 is to cover this area, provide additional neutron shielding, prevent neutron leakage, and ensure safety.
[0025] Embodiment 4: On the basis of Embodiment 3, the hoisting assembly 8 includes a mounting plate 25. Reinforcement rods 26 are fixedly sleeved at the four corners of the mounting plate 25. The reinforcement rods 26 penetrate and are fixed between the reinforcement support plate 5 and the top support plate 6 and are welded and fixed to the upper surface of the bottom plate 2 at the bottom. The reinforcement rods 26 are fixedly installed between the bottom plate 2, the reinforcement support plate 5, and the top support plate 6, further enhancing the overall strength and stiffness of the fixed frame structure, so that the spent fuel storage and transportation hanging basket is not prone to deformation under normal working conditions and seismic conditions, or the spent fuel assemblies are still in a subcritical and natural cooling circulation cooling state after deformation. A limiting sleeve 27 is fixedly connected to the upper surface of the mounting plate 25, and a mounting shell 28 is fixedly connected to the lower surface of the mounting plate 25. A limiting piece 29 is sleeved at the bottom of the mounting shell 28 and fixedly connected to the limiting piece 29. A limiting column 30 is arranged between the limiting sleeve 27 and the mounting shell 28. The limiting column 30 is sleeved in the middle of the mounting plate 25 and fixedly connected to the mounting plate 25. The bottom of the limiting column 30 is fixedly connected to the top of the connecting column 31. The mounting plate 25 fixes the limiting sleeve 27, the mounting shell 28, and the limiting column 30, and the limiting column 30 fixedly supports the connecting column 31. The axis center positions of the limiting sleeve 27, the mounting shell 28, the limiting piece 29, the limiting column 30, and the connecting column 31 are all penetrated. Chamfers 32 are symmetrically opened on both sides of the bottom of the connecting column 31. The chamfers 32 are slidably connected to the cylindrical protrusions at one end of the hook plate 33. The other end of the hook plate 33 is fixedly connected with a hook block 34. There are two hook plates 33, which are arranged in a cross shape on both sides of the grasping rod 35. The grasping rod 35 is rotatably connected to the middle of the hook plate 33 through a limiting pin. Limiting rods 36 are fixedly sleeved at one end of each of the two hook plates 33 close to the connecting column 31. The two limiting rods 36 are fixedly connected through a tension spring 37. The grasping rod 35 is slidably sleeved between the limiting sleeve 27, the limiting column 30, and the connecting column 31.
[0026] When it is necessary to transfer the entire fixed frame structure, the external gripper is positioned to tightly grip the gripper rod 35, and the gripper rod 35 is lifted upward. The gripper rod 35 slides within it under the limitation of the limit sleeve 27, the limit post 30, and the connecting post 31. Thus, the gripper rod 35 drives the end of the hook plate 33 fixedly connected with the cylindrical protrusion to move upward under the connection of the limit pin, so that this end slides between the inclined surfaces 32 provided on both sides of the connecting post 31. Consequently, the tension spring 37 is stretched under the limitation of the limit rod 36, and the ends of the two hook plates 33 fixedly connected with the hook blocks 34 move away from each other until the hook blocks 34 abut against one side of the limit piece 29. As the gripper rod 35 continues to be pulled upward, through the fixed connection between the mounting shell 28 and the mounting plate 25 and the fixed connection between the mounting plate 25 and the reinforcing rod 26, the entire frame is lifted and pulled up, thus facilitating the transfer of the entire device. When the gripper places the entire frame structure in the appropriate position and no longer pulls up the gripper rod 35, at this time, under the reverse elastic force of the tension spring 37, the hook plates 33 are indirectly made to move towards each other, and then the hook plates 33 are reset, facilitating subsequent use.
[0027] 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 spent fuel storage and transportation basket, comprising a buffer seat assembly (1), characterized in that: A bottom plate (2) is arranged on the upper side of the buffer seat assembly (1), storage sleeves (3) are arranged in a rectangular array on the upper surface of the bottom plate (2), and a water inlet hole (4) is provided between the bottom of the storage sleeve (3) and the bottom plate (2); A reinforcement support plate (5) is sleeved on the middle of the storage casing (3) and is gap-matched with the reinforcement support plate (5); a top support plate (6) is sleeved on the top of the storage casing (3) and is in contact with the inner wall of the top support plate (6); a perforated plate (7) is detachably installed in the top support plate (6); and hoisting components (8) are provided at four corners of the upper surface of the top support plate (6); The four corners of the outer side walls of the bottom plate (2), the reinforcement bracket plate (5) and the top bracket plate (6) are fixedly connected to the supporting steel plate (9) by bolts (10).
2. A spent fuel storage and transportation hanging basket according to claim 1, characterized in that: The buffer seat assembly (1) comprises a limit frame (11), the limit frame (11) is slidably connected to the bottom plate (2) and the support steel plate (9), the outer wall of the limit frame (11) is provided with drainage holes (12) in a rectangular array, and the inner wall of the limit frame (11) is provided with buffers (13) in a rectangular array.
3. A spent fuel storage and transportation hanging basket according to claim 2, characterized in that: One end of the buffer (13) is fixedly connected to the inner wall of the limit frame (11), and the other end of the buffer (13) is rotatably connected to one end of a connecting rod (15) via a pin shaft (14), and the other end of the connecting rod (15) is rotatably connected to a connecting seat (16) via the pin shaft (14).
4. A spent fuel storage and transportation hanging basket according to claim 3, characterized in that: The upper surface of the connecting seat (16) is fixedly connected to the lower surface of the bottom plate (2); a damper (17) is provided on one side of the connecting seat (16); the damper (17) is fixedly installed between the bottom inner wall of the limiting frame (11) and the lower surface of the bottom plate (2).
5. A spent fuel storage and transportation hanging basket according to claim 4, characterized in that: The bottom plate (2) is welded to the bottom of the storage sleeve (3), a flexible buffer layer (18) is provided between the storage sleeve (3) and the reinforcement support plate (5), cavities (19) are provided at four corners of the inner wall of the top support plate (6), and a pressing sheet (20) is installed on one side of the cavity (19).
6. A spent fuel storage and transportation hanging basket according to claim 5, characterized in that: One end of the pressing sheet (20) is fixedly connected to the bottom of the spring (21), the top of the spring (21) is fixedly connected to the top of the inner wall of the cavity (19), the lower surface of the pressing sheet (20) abuts against the upper surface of the orifice plate (7), the lower surface of the pressing sheet (20) abuts against the top of the storage sleeve (3), a stainless steel pipe (22) is fixedly installed inside the storage sleeve (3), a titanium-based composite plate (23) is fixedly connected to the outer ring surface of the stainless steel pipe (22), and through holes (24) are formed on the surfaces of the reinforcement support plate (5) and the top support plate (6).
7. The spent fuel storage and transportation hanging basket according to claim 1, characterized in that: The hoisting assembly (8) comprises a mounting plate (25), wherein the four corners of the mounting plate (25) are fixedly sleeved with reinforcing rods (26), the reinforcing rods (26) being passed through and fixed between the reinforcing bracket plate (5) and the top bracket plate (6), and the bottom is welded and fixed to the upper surface of the bottom plate (2).
8. The spent fuel storage and transportation hanging basket according to claim 7, characterized in that: The upper surface of the mounting plate (25) is fixedly connected to a limiting sleeve (27), the lower surface of the mounting plate (25) is fixedly connected to a mounting shell (28), the bottom of the mounting shell (28) is sleeved with a limiting piece (29) and is fixedly connected to the limiting piece (29), a limiting column (30) is arranged between the limiting sleeve (27) and the mounting shell (28), the limiting column (30) is sleeved in the middle of the mounting plate (25) and is fixedly connected to the mounting plate (25), and the bottom of the limiting column (30) is fixedly connected to the top of the connecting column (31).
9. A spent fuel storage and transportation hanging basket according to claim 8, characterized in that: The bottom of the connecting column (31) is symmetrically provided with inclined surfaces (32), the inclined surfaces (32) are slidably connected to one end of the hook plate (33), the other end of the hook plate (33) is fixedly connected to a hook block (34), two hook plates (33) are provided and arranged crosswise, a grab bar (35) is installed between the hook plates (33), the grab bar (35) and the middle part of the hook plate (33) are rotatably connected via a limit pin, the ends of the two hook plates (33) close to the connecting column (31) are fixedly sleeved with a limit rod (36), the two limit rods (36) are fixedly connected via a tension spring (37), and the grab bar (35) is slidably sleeved between the limit sleeve (27), the limit column (30) and the connecting column (31).