Automatic proportioning and mixing device for grounding electrode coke
By combining automated pretreatment and dynamic mixing mechanisms, the problems of precision and uniformity in the grounding electrode coke batching and mixing device are solved, realizing an efficient and continuous mixing process and improving production efficiency and mixing quality.
Patent Information
- Application Number
- CN202511899869.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-16
- Publication Date
- 2026-02-17
AI Technical Summary
Existing grounding electrode coke batching and mixing devices suffer from problems such as poor batching accuracy, lack of effective pretreatment, and discrete and discontinuous process flow, resulting in uneven mixing and low production efficiency.
The system employs an automated pretreatment mechanism and a dynamic mixing mechanism, using a filter screen for screening, a vertical cutting plate for crushing, and a dynamic scraper toothed plate for stirring to achieve precise screening and uniform mixing of coke.
It improves the accuracy and uniformity of coke ingredient mixing, enhances production efficiency, eliminates mixing dead zones, and ensures the continuity of the mixing process and integrated automated production.
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Figure CN121534595A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of coke processing technology, specifically to an automatic batching and mixing device for grounded coke. Background Technology
[0002] In fields such as power and lightning protection grounding, grounding electrodes are key components ensuring the safe and stable operation of electrical equipment. Coke, due to its excellent conductivity and corrosion resistance, is widely used as the main material for grounding electrode fillers. In practical applications, different types and particle sizes of coke, along with other ingredients, are typically mixed in specific proportions to optimize the conductivity and current dissipation characteristics of the grounding electrode.
[0003] Currently, the batching and mixing devices for grounded coke have the following significant defects: (1) Poor batching accuracy: Most conventional devices adopt volumetric feeding, which can easily cause significant differences in material bulk density and particle size; (2) Lack of effective pretreatment operations: There may be large particles that clump together in coke or other raw materials, and simple screening cannot effectively break them up. If these large particles directly enter the mixing process, they will segregate during the mixing process due to the large differences in particle size, making it difficult to achieve true uniform mixing, thus becoming a potential hidden danger affecting product quality; (3) Discrete process flow and insufficient continuity: Screening, crushing, mixing and other processes are usually carried out separately and independently, and materials need to be transferred and transported. This not only increases the risk of material loss and environmental pollution, but also makes it difficult to achieve continuous and integrated automated production, thus restricting the improvement of overall production efficiency.
[0004] To address this technical deficiency, a solution is proposed. Summary of the Invention
[0005] The purpose of this invention is to automate the entire process of coke raw material from screening and pretreatment to dynamic mixing, thereby achieving high efficiency, precision and stability in coke batching and mixing. This effectively solves the problems of low efficiency, lack of precision and uneven mixing in traditional equipment during the coke batching and mixing process, and significantly improves work efficiency and mixing uniformity.
[0006] The objective of this invention can be achieved through the following technical solution: an automatic batching and mixing device for grounded coke, comprising a batching bin, a guide frame provided on the top surface of the batching bin away from its opening end, and multiple parallel material troughs provided inside the guide frame, a pretreatment mechanism provided at the bottom of the guide frame inside the batching bin, and a mixing bin provided at the opening end inside the batching bin, and a dynamic mixing mechanism provided inside the mixing bin;
[0007] The batching bin has several sets of partitions fixedly installed on the inner wall away from its opening end. Each set of partitions has an opening slot inside. An inclined concave guide frame is movably installed between two adjacent sets of partitions. The concave guide frame is located in the middle of two adjacent partitions and is hinged to the partition. The concave guide frame and the material trough are matched in the vertical direction, and a filter screen plate adapted to the material trough is embedded on the upper surface of the concave guide frame.
[0008] Furthermore, the pretreatment mechanism includes a slide that is movably mounted on the surface of one of the concave guide frames, and the positions of the opening slots in the slide and the partition are corresponding front and back. A balance plate is hinged at the center of the slide, and vertical cutting plates are respectively hinged at both ends of the balance plate. A hinge shaft is provided at the center of the top surface of the balance plate. A cylinder is provided between the hinge shaft and the inner side wall of the slide, and the output end of the cylinder is hinged to the hinge shaft.
[0009] Furthermore, a helical slider is fixedly installed at the center of the top surface of the slide, and a longitudinal lead screw is helically threaded inside the helical slider. A drive motor is provided between the rear end of the longitudinal lead screw and the inner side wall of the slide.
[0010] Furthermore, a sliding shaft is movably sleeved at the front end of the longitudinal lead screw, and a transverse lead screw is spirally sleeved at the bottom end inside the sliding shaft. A second drive motor is provided between the end of the transverse lead screw and the inner side wall of the batching bin.
[0011] Furthermore, the dynamic mixing mechanism includes a movable frame movably installed on the top surface of the mixing hopper, and a toothed groove group is provided on one inner wall of the movable frame. A vertical pole runs through the inside of the movable frame, and a toothed roller sleeve is fixedly sleeved on the outer position of the pole corresponding to the bottom end of the movable frame. A scraper toothed plate is fixedly installed at the bottom of the pole, and a double-layer circular plate is fixedly sleeved at the top of the pole.
[0012] Furthermore, the dynamic mixing mechanism also includes a third drive motor located at the opening end of the inner wall at the rear end of the batching hopper, and a spiral drum is fixedly installed on the output shaft of the third drive motor. A movable sleeve is spirally sleeved on the outside of the spiral drum, and an extension guide plate is fixedly installed on the side wall of the movable sleeve. The end of the extension guide plate is movably sleeved on the outside of the upright, and the extension guide plate penetrates the inside of the positioning frame. The positioning frame is fixedly installed inside the batching hopper and located adjacent to the mixing hopper and the spiral drum.
[0013] Furthermore, a cylinder three is installed near the top surface of the extension plate close to the upright, and a lifting plate is fixedly connected to the top output end of the cylinder three, with the end of the lifting plate pressing against the gap between the two-layer circular plates.
[0014] Compared with the prior art, the beneficial effects of the present invention are:
[0015] 1. This invention, by setting up a pretreatment mechanism, first uses a filter screen to pre-screen the coke, removing impurities and fine particles; at the same time, through the alternating lifting and lowering motion of the vertical cutting plate, large coke particles are precisely crushed and loosened, making the coke particle size more uniform, effectively solving the problem of insufficient mixing caused by uneven particles in the subsequent mixing process.
[0016] 2. By setting up a dynamic mixing mechanism and using a scraper toothed plate that can be raised and rotated, the present invention can automatically adjust the mixing range according to the amount of material through the combination of linear scraping and self-rotating mixing. This design ensures that the material in different positions in the mixing bin can be fully stirred, eliminates mixing dead zones, and improves the uniformity and consistency of mixing. Attached Figure Description
[0017] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.
[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention;
[0019] Figure 2 This is a schematic diagram of the ingredient silo and its internal structure according to the present invention;
[0020] Figure 3 This is a cross-sectional view of the combination of the partition, concave guide frame and carriage structure of the present invention;
[0021] Figure 4 This is a top view of the ingredient hopper of the present invention;
[0022] Figure 5 This is a plan view of the combination of the mixing bin and the dynamic mixing mechanism of the present invention.
[0023] Figure 6 This is a half-sectional view of the ingredient storage bin diagram of the present invention;
[0024] Figure 7 This is a partial schematic diagram of the combination of the ingredient silo and the dynamic mixing mechanism of the present invention.
[0025] In the diagram: 1. Batching bin; 2. Guide frame; 3. Pre-treatment mechanism; 4. Mixing bin; 5. Dynamic mixing mechanism; 101. Partition plate; 102. Concave guide frame; 31. Slide frame; 32. Balance plate; 33. Vertical cutting plate; 34. Cylinder 1; 35. Spiral slider; 36. Longitudinal lead screw; 37. Drive motor 1; 38. Sliding shaft; 39. Transverse lead screw; 310. Drive motor 2; 51. Movable frame; 52. Upright pole; 53. Toothed roller sleeve; 54. Scraper toothed plate; 55. Double-layer circular plate; 56. Drive motor 3; 57. Spiral drum; 58. Movable sleeve; 59. Extension guide plate; 510. Positioning frame; 511. Cylinder 3; 512. Lifting plate. Detailed Implementation
[0026] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0027] Example 1: Please refer to Figure 1 - Figure 4 As shown, an automatic batching and mixing device for grounded coke includes a batching bin 1. A guide frame 2 is provided on the top surface of the batching bin 1 away from its opening end, and multiple parallel material troughs are provided inside the guide frame 2. A pretreatment mechanism 3 is provided at the bottom of the guide frame 2 inside the batching bin 1. A mixing bin 4 is provided at the opening end inside the batching bin 1, and a dynamic mixing mechanism 5 is provided inside the mixing bin 4.
[0028] Among them, several sets of partitions 101 are fixedly installed on the inner wall of the batching bin 1 away from its opening end. Each set of partitions 101 has an opening groove inside. An inclined concave guide frame 102 is movably installed between two adjacent sets of partitions 101. The concave guide frame 102 is located in the middle of two adjacent partitions 101, and the concave guide frame 102 and the partition 101 are hinged. The positions of the concave guide frame 102 and the material trough are matched in the vertical direction. The upper surface of the concave guide frame 102 is embedded with a filter screen plate that is compatible with the material trough for screening coke during the material guiding process.
[0029] Feeding stage: Coke, graphite powder and bentonite are poured into the respective feed troughs in the feed guide frame 2. The coke slides down the feed troughs onto the corresponding concave feed guide frame 102. Since the concave feed guide frame 102 is inclined and has a filter screen embedded on its upper surface, impurities and fine particles with a particle size smaller than the filter screen aperture will fall through the filter screen during the downward movement, thus achieving the initial screening of the coke.
[0030] The pretreatment mechanism 3 includes a slide 31 movably mounted on the surface of one of the concave guide frames 102. The slide 31 and the opening slots in the partition 101 are positioned in a front-to-back correspondence. A balance plate 32 is hinged at the center of the slide 31. Vertical cutting plates 33 are hinged at both ends of the balance plate 32. A hinge shaft is provided at the center of the top surface of the balance plate 32. A cylinder 34 is provided between the hinge shaft and the inner wall of the slide 31. The output end of the cylinder 34 is hinged to the hinge shaft to drive the balance plate 32 to swing around the hinge, thereby driving the two vertical cutting plates 33 to rise and fall alternately, so as to crush and loosen the coke on the concave guide frame 102.
[0031] A spiral slider 35 is fixedly installed at the center of the top surface of the slide 31, and a longitudinal lead screw 36 is spirally threaded inside the spiral slider 35. A drive motor 37 is provided between the rear end of the longitudinal lead screw 36 and the inner side wall of the slide 31. A sliding shaft 38 is movably sleeved at the front end of the longitudinal lead screw 36, and a transverse lead screw 39 is spirally sleeved at the bottom end inside the sliding shaft 38. A drive motor 310 is provided between the end of the transverse lead screw 39 and the inner side wall of the mixing bin 1, which is used to drive the sliding shaft 38 and the entire slide 31 to move laterally along the transverse lead screw 39, thereby realizing the reciprocating motion of the pretreatment mechanism 3 in a two-dimensional plane.
[0032] Before the initially separated coke is introduced into the mixing bin 4, the large coke particles remaining on the surface of the concave guide frame 102 need to be cut. The specific operation process is as follows: First, the drive motor 37 is started, which drives the longitudinal screw 36 to rotate and drives the spiral slider 35 to move longitudinally along the longitudinal screw 36, thereby driving the slide 31 to move longitudinally. The slide 31 first slides to the top of the concave guide frame 102, and the concave guide frame 102, which is pressed by the slide 31, tends to be flat. At this time, the trough feeds material onto the surface of the concave guide frame 102, which tends to be flat. The material first separates on its own, and the large coke particles or other large particles remain in the concave guide frame 102. On the upper surface of 02, the push rod at the output end of cylinder 34 is extended and retracted, driving the balance plate 32 to swing around the hinge. The balance plate 32 drives the two vertical cutting plates 33 to rise and fall alternately. The vertical cutting plates 33 cut the large coke particles stuck on the surface of the concave guide frame 102, crushing and loosening them to make their particle size more uniform, which is convenient for subsequent mixing operations. At the same time, the drive motor 310 is started, driving the transverse screw 39 to rotate. The rotation of the transverse screw 39 causes the sliding shaft 38 to move laterally along the transverse screw 39. The sliding shaft 38 drives the slide frame 31 to move laterally. Through longitudinal movement, the coke particles on the upper surface of the concave guide frame 102 are fully cut.
[0033] It is worth noting that after the material on the surface of the concave guide frame 102 is cut, the drive motor 37 is continuously started, driving the longitudinal screw 36 to rotate, and driving the spiral slider 35 and the slide 31 to move longitudinally continuously until the slide 31 moves through the opening slot to the surface of the next set of concave guide frames 102. The above operation is repeated, and the large particles on the surface of the next set of concave guide frames 102 are cut in the same way. The previous set of concave guide frames 102, which has lost the pressure of the slide 31 component, is reset and tilted so that the material can be introduced into the mixing bin 4. Under the joint drive of the longitudinal screw 36 and the transverse screw 39, the slide 31 can move precisely to the designated position of each concave guide frame 102, ensuring that the large particles of coke on all concave guide frames 102 can be effectively crushed and loosened.
[0034] After the large coke particles on all the concave guide frames 102 are cut, the screened and cut coke and other ingredients will continue to slide down the concave guide frames 102 and eventually fall into the mixing bin 4. At this time, the dynamic mixing mechanism 5 in the mixing bin 4 starts to work.
[0035] Example 2: Please refer to Figure 4 - Figure 7 As shown, the dynamic mixing mechanism 5 includes a movable frame 51 movably installed on the top surface of the mixing bin 4, and a toothed groove group is provided on one side inner wall of the movable frame 51. A vertical pole 52 is vertically inserted inside the movable frame 51, and a toothed roller sleeve 53 is fixedly sleeved on the outer position of the pole 52 corresponding to the bottom end of the movable frame 51. A scraper toothed plate 54 is fixedly installed at the bottom of the pole 52, and a double-layer circular plate 55 is fixedly sleeved on the top of the pole 52 for cooperation with the lifting mechanism.
[0036] The dynamic mixing mechanism 5 also includes a drive motor 56 located at the opening end of the inner wall at the rear end of the batching silo 1. A spiral drum 57 is fixedly mounted on the output shaft of the drive motor 56. A movable sleeve 58 is spirally sleeved on the outside of the spiral drum 57. An extension guide plate 59 is fixedly mounted on the side wall of the movable sleeve 58. The end of the extension guide plate 59 is movably sleeved on the outside of the upright 52. The extension guide plate 59 penetrates the inside of the positioning frame 510. The positioning frame 510 is fixedly installed inside the batching silo 1 and located in the mixing area. The adjacent position of the bin 4 and the spiral drum 57 is used to guide and limit the movement of the extension guide plate 59. A cylinder 3 511 is installed on the top surface of the extension guide plate 59 near the upright 52, and a lifting plate 512 is fixedly connected to the top output end of the cylinder 3 511. The end of the lifting plate 512 presses against the gap between the double-layer circular plates 55. When the cylinder 3 511 is activated, the upright 52 can be raised or lowered through the lifting plate 512, thereby driving the scraper toothed plate 54 to rise and fall in the mixing bin 4 and adjust its mixing range.
[0037] Initial mixing stage: Several materials are poured into the mixing bin 4 in sequence. First, drive motor 3 56 is turned on. Drive motor 3 56 drives the spiral drum 57 to rotate, forcing the movable sleeve 58 to move longitudinally along its spiral trajectory. The movement of the movable sleeve 58 drives the extension guide plate 59 to move under the guidance and limiting action of the positioning frame 510. The movement of the extension guide plate 59 drives the upright 52 to move along the internal movable frame 51. At this time, the scraper tooth plate 54 at the bottom of the upright 52 performs initial scraping in the mixing bin 4.
[0038] As more material is poured into the mixing bin 4, when it is necessary to adjust the mixing range of the scraper toothed plate 54, cylinder 3 511 is first activated. The push rod extends and retracts, causing the lifting plate 512 to rise. The lifting plate 512, by pressing against the gap between the double-layer circular plates 55, causes the upright 52 and the scraper toothed plate 54 to rise within the mixing bin 4. At this time, the toothed roller sleeve 53 enters the movable frame 51 and meshes with the toothed groove assembly. As the upright 52 moves linearly, it rotates, thus transforming the linear scraping motion into a rotating mixing motion. By changing the mixing range of the scraper toothed plate 54 within the mixing bin 4, materials at different locations can be fully and uniformly mixed. Under the continuous operation of the dynamic mixing mechanism 5, the screened and cut coke and other ingredients are fully mixed within the mixing bin 4, ultimately forming a uniform mixture and completing the entire automatic batching and mixing process.
[0039] Working principle: When using this invention, the drive motor 37 is first started, which drives the longitudinal screw 36 to rotate and drives the spiral slider 35 to move longitudinally along the longitudinal screw 36, thereby driving the slide 31 to move longitudinally. The slide 31 first slides to the top of the concave guide frame 102. The concave guide frame 102, which is pressed by the slide 31, tends to be flat. At this time, the material in the trough is applied to the surface of the concave guide frame 102, which tends to be flat. During the process of the material sliding down, small particles of impurities and fine particles fall through the filter screen, while large particles of coke material remain on the upper surface of the concave guide frame 102.
[0040] Next, cylinder 34 is started, and the push rod can be used to extend and retract to drive the balance plate 32 to swing around the hinge. The balance plate 32 drives the two vertical cutting plates 33 to rise and fall alternately, cutting the large coke particles stuck on the surface of the concave guide frame 102, making them crushed and loose. At the same time, drive motor 310 is started, driving the transverse screw 39 to rotate. The rotation of the transverse screw 39 causes the sliding shaft 38 to move laterally along the transverse screw 39. The sliding shaft 38 drives the slide frame 31 to move laterally. Through longitudinal and transverse movement, the coke particles on the upper surface of the concave guide frame 102 are fully cut.
[0041] After the material on the surface of the concave guide frame 102 is completely cut, the drive motor 37 is continuously started, driving the longitudinal lead screw 36 to rotate, and driving the spiral slider 35 and the carriage 31 to move longitudinally continuously until the carriage 31 moves through the opening slot to the surface of the next set of concave guide frames 102. The above operation is repeated to cut the large particles on the surface of the next set of concave guide frames 102 in the same way. The previous set of concave guide frames 102, which no longer has the pressure of the carriage 31 component, is under the action of the hinge force. The material is introduced into the mixing bin 4 by tilting the slide 31. Driven by the longitudinal screw 36 and the transverse screw 39, the slide 31 moves precisely to the designated position of each concave guide frame 102, ensuring that the large coke particles on all concave guide frames 102 can be effectively crushed and loosened. After the large coke particles on all concave guide frames 102 are cut, the screened and cut coke and other ingredients continue to slide down the concave guide frames 102 and fall into the mixing bin 4.
[0042] Then, drive motor 3 56 is turned on, which drives the spiral drum 57 to rotate, forcing the movable sleeve 58 to move longitudinally along its spiral trajectory. The movable sleeve 58 drives the extension guide plate 59 to move under the guidance and limiting action of the positioning frame 510. The extension guide plate 59 drives the upright 52 to move along the internal movable frame 51. The scraper toothed plate 54 at the bottom of the upright 52 performs initial dispersion in the mixing bin 4. When it is necessary to adjust the mixing range of the scraper toothed plate 54, cylinder 3 511 is started, and the push rod extends... The retraction drives the lifting plate 512 to rise. The lifting plate 512, by pressing against the gap between the double-layer circular plates 55, drives the upright 52 and the scraper toothed plate 54 to rise in the mixing bin 4. At this time, the toothed roller sleeve 53 enters the interior of the movable frame 51 and meshes with the tooth groove group. As the upright 52 moves linearly, the upright 52 and the scraper toothed plate 54 rotate, converting the linear scraping motion into a rotational mixing motion, so that the materials at different positions are fully and evenly mixed, and finally a uniform mixture is formed, completing the entire automatic batching and mixing process.
[0043] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.
Claims
1. An automatic batching and mixing device for grounded coke, characterized in that: It includes a batching bin (1), a guide frame (2) is provided on the top surface of the batching bin (1) away from its opening end, and multiple parallel material troughs are provided inside the guide frame (2). A pre-treatment mechanism (3) is provided at the bottom of the guide frame (2) inside the batching bin (1). A mixing bin (4) is provided inside the batching bin (1) at its opening end, and a dynamic mixing mechanism (5) is provided inside the mixing bin (4). Among them, the mixing bin (1) has several sets of partitions (101) fixedly installed on the inner wall away from its opening end. Each set of partitions (101) has an opening groove inside. An inclined concave guide frame (102) is movably installed between two adjacent sets of partitions (101). The concave guide frame (102) is located in the middle of two adjacent partitions (101), and the concave guide frame (102) and the partition (101) are hinged. The concave guide frame (102) and the material trough are matched in the vertical direction, and a filter screen plate adapted to the material trough is embedded on the upper surface of the concave guide frame (102).
2. The automatic batching and mixing device for grounded coke according to claim 1, characterized in that, The pretreatment mechanism (3) includes a slide (31) movably mounted on the surface of one of the concave guide frames (102), and the positions of the opening slots in the slide (31) and the partition (101) are corresponding front and back. A balance plate (32) is hinged at the center of the slide (31), and vertical cutting plates (33) are hinged at both ends of the balance plate (32). A hinge shaft is provided at the center of the top surface of the balance plate (32), and a cylinder (34) is provided between the hinge shaft and the inner side wall of the slide (31). The output end of the cylinder (34) is hinged to the hinge shaft.
3. The automatic batching and mixing device for grounded coke according to claim 2, characterized in that, A spiral slider (35) is fixedly installed at the center of the top surface of the slide (31), and a longitudinal screw (36) is spirally threaded inside the spiral slider (35). A drive motor (37) is provided between the rear end of the longitudinal screw (36) and the inner side wall of the slide (31).
4. The automatic batching and mixing device for grounded coke according to claim 3, characterized in that, The longitudinal lead screw (36) is movably sleeved with a sliding shaft (38), and a transverse lead screw (39) is spirally sleeved at the bottom of the sliding shaft (38). A drive motor (310) is provided between the end of the transverse lead screw (39) and the inner wall of the batching bin (1).
5. The automatic batching and mixing device for grounded coke according to claim 1, characterized in that, The dynamic mixing mechanism (5) includes a movable frame (51) movably installed on the top surface of the mixing bin (4), and a toothed groove group is provided on one side inner wall of the movable frame (51). A vertical rod (52) runs through the interior of the movable frame (51), and a toothed roller sleeve (53) is fixedly sleeved on the outer position of the bottom end of the movable frame (51) corresponding to the vertical rod (52). A scraper toothed plate (54) is fixedly installed at the bottom of the vertical rod (52), and a double-layer circular plate (55) is fixedly sleeved on the top of the vertical rod (52).
6. The automatic batching and mixing device for grounded coke according to claim 5, characterized in that, The dynamic mixing mechanism (5) also includes a drive motor three (56) located at the opening end of the inner wall of the rear end of the batching bin (1), and a spiral drum (57) is fixedly installed on the output shaft of the drive motor three (56). A movable sleeve (58) is spirally sleeved on the outside of the spiral drum (57), and an extension guide plate (59) is fixedly installed on the side wall of the movable sleeve (58). The end of the extension guide plate (59) is movably sleeved on the outside of the upright (52), and the extension guide plate (59) penetrates the inside of the positioning frame (510). The positioning frame (510) is fixedly installed inside the batching bin (1) and located adjacent to the mixing bin (4) and the spiral drum (57).
7. The automatic batching and mixing device for grounded coke according to claim 6, characterized in that, The extension guide plate (59) is equipped with a cylinder three (511) near the top surface of the upright (52), and a lifting plate (512) is fixedly connected to the top output end of the cylinder three (511). The end of the lifting plate (512) presses against the gap of the double-layer circular plate (55).