Intelligent screening equipment for petroleum coke production
By introducing buffer cylinder and feed cylinder structures into the intelligent screening equipment for petroleum coke production, the problems of screen recess and powder drift are solved, and efficient screening and safe operation are achieved.
Patent Information
- Application Number
- CN202521120414.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-04
- Publication Date
- 2025-08-22
- Estimated Expiration
- 2035-06-04
AI Technical Summary
When the existing vibrating screen is injected with petroleum coke, the petroleum coke hits the same part of the uppermost screen, causing the screen to be recessed, affecting the screening effect, and the powder is prone to drift.
An intelligent screening device is designed, adopting a buffer cylinder and feed cylinder structure. The petroleum coke first falls on the buffer block to buffer to avoid direct impact on the uppermost screen. The large piece of petroleum coke is cut off by an annular cutter. The feed cylinder is connected to the outside world only through a small diameter, combining the rubber film and shock absorption device to prevent the powder from floating.
Effectively prevent the screening mesh from being recessed, improve the screening effect, reduce powder drifting, and ensure the stability and safety of the screening process.
Smart Images
Figure CN223249868U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of screening equipment, in particular to an intelligent screening device for petroleum coke production. Background Art
[0002] Petroleum coke is a by-product of petroleum refining. It is a block and granular substance mainly composed of carbon. It can be used as a raw material for the production of industrial materials and a calcination material. Before use, petroleum coke needs to be screened through screening equipment to ensure the uniformity of the petroleum coke particles and meet the requirements of specific industrial applications. The common petroleum coke screening equipment is a vibrating screen. When feeding the existing vibrating screen, the feed port position is fixed. Each time the petroleum coke is poured from directly above the vibrating screen, the petroleum coke hits the same part (center) of the top screen of the vibrating screen each time. Over time, the top screen will sag, and the petroleum coke intercepted on the screen needs to move to the outer edge of the screen through vibration and be discharged through a pipe. If the screen is dented, it will affect the discharge of the intercepted petroleum coke, and the intercepted petroleum coke will remain on the screen, affecting the screening effect of the screen. Utility Model Content
[0003] In order to overcome the disadvantage that each time petroleum coke is poured, it hits the same part (center) of the uppermost screen of the vibrating screen. Over time, the uppermost screen becomes concave, which will affect the discharge of the intercepted petroleum coke, and the intercepted petroleum coke remains on the screen, affecting the screening effect of the screen, the utility model provides an intelligent screening equipment for petroleum coke production.
[0004] The technical solution is: an intelligent screening equipment for petroleum coke production, including a base; a plurality of shock-absorbing springs are fixedly connected to the base; one end of all shock-absorbing springs is fixedly connected to a vibration base; a plurality of vibration motors are installed on the vibration base; it also includes a screen drum, a feed drum and a buffer drum; a plurality of screen drums are installed on the vibration base from bottom to top; a screen mesh is fixedly connected in each screen drum; the mesh openings of different screen meshes increase from bottom to top; each screen drum is connected to a discharge pipe; a top cover is fixed on the top screen drum; the top cover is connected to the feed drum; the feed drum is connected to the top screen drum; a buffer drum is connected in the feed drum; the buffer drum is composed of a limit ring, a plurality of connecting rods and a buffer block; the bottom surface of the limit ring is in contact with the top surface of the feed drum; the connecting rod is longer than the length of the feed drum; the buffer block is connected to the bottom of all connecting rods and is located below the feed drum.
[0005] As an improvement to the above solution, it further includes a connecting frame and a rubber membrane; the connecting frame is fixedly connected to the base; the connecting frame is fixedly connected to the feeding barrel; the rubber membrane is connected to the feeding barrel; and the rubber membrane is fixedly connected to the top cover.
[0006] As an improvement to the above solution, it also includes an intercepting rod; the buffer cylinder is detachably connected to the feed cylinder; a plurality of intercepting rods are fixed to the limit ring; the bottoms of all intercepting rods are in contact with the buffer block; all intercepting rods and all connecting rods are arranged in a ring with equal distances.
[0007] As an improvement to the above solution, an annular cutter is further included; the annular cutter is fixedly connected to the bottom of the feeding barrel.
[0008] As an improvement to the above solution, the buffer block is conical.
[0009] As an improvement to the above solution, a closing cover is connected to the feeding barrel; the closing cover is in contact with the limiting ring.
[0010] As an improvement to the above solution, the closing cover is embeddedly connected to the feeding barrel.
[0011] As an improvement to the above solution, a rubber handle is provided on the closing cover.
[0012] As an improvement to the above solution, a plurality of metal pads are fixedly connected to the bottom of the base.
[0013] As an improvement to the above scheme, it also includes a sliding rod, a connecting block and a limit block; each connecting rod is slidably connected to a sliding rod; the bottom of each sliding rod is rotatably connected to a connecting block; all connecting blocks are fixedly connected to the buffer block; two sliding grooves 1 are provided on the limit ring; each connecting rod is provided with a sliding groove 2; each sliding groove 2 is connected to the adjacent sliding groove 1; a limit block is fixedly connected to the top of each sliding rod; the limit block is located on the upper side of the limit ring; the limit block and the sliding groove 1 are perpendicular to each other.
[0014] Beneficial effect: The utility model realizes that the petroleum coke poured into the screen drum through the feeding drum first falls on the buffer block for buffering, thereby avoiding direct impact on the screen of the uppermost screen drum, and preventing the impact of multiple loadings and repeated impact on the center of the screen, causing the screen to sag and affecting the discharge of the intercepted petroleum coke;
[0015] During the vibrating screening process, the feed drum does not vibrate along with the screen drum, making it easier for users to pour petroleum coke into the feed drum. The top screen drum is only connected to the outside world through the feed drum, which has a small opening to prevent powder from scattering when pouring petroleum coke.
[0016] The intercepting rods and all the connecting rods are arranged in a circular pattern with equal spacing. The petroleum coke poured into the feed drum is first placed in the buffer drum, which performs the initial screening of large pieces of petroleum coke to prevent them from falling on the screen of the top screen drum and being difficult to be discharged through vibration.
[0017] When the buffer tube is lifted out of the feed barrel, the part of the large piece of petroleum coke extending out of the buffer tube will be squeezed by the annular cutter and cut off by the annular cutter, thereby preventing the part of the large piece of petroleum coke extending out from the bottom surface of the feed barrel from being blocked and affecting the lifting of the buffer tube from the feed barrel. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 This is a schematic diagram of the three-dimensional structure of the intelligent screening equipment for petroleum coke production of the utility model;
[0019] Figure 2 This is a schematic diagram of the top area of the three-dimensional structure of the intelligent screening equipment for petroleum coke production of the utility model, in which the screen drum is cut away;
[0020] Figure 3 This is a front view of the intelligent screening equipment for petroleum coke production of the utility model, with the screen drum being treated as a cross-section;
[0021] Figure 4 This is a front view of the screen drum, feed drum, buffer drum and connecting frame assembly of the present invention, with the screen drum being a cross-sectional view;
[0022] Figure 5 This is a schematic diagram of the three-dimensional structure of the buffer cylinder of the present utility model;
[0023] Figure 6 This is a schematic diagram of the three-dimensional structure of the buffer block and the intercepting rod of the utility model in a separated state;
[0024] Figure 7 It is a front view of the combination of the limiting ring, connecting rod, buffer block, sliding rod, connecting block and limiting block of the utility model.
[0025] The numbers in the figure are: 1-base, 11-shock-absorbing spring, 12-vibration seat, 13-vibration motor, 14-metal pad, 2-screen drum, 21-screen, 22-discharge pipe, 23-top cover, 3-feeding drum, 31-closing cover, 32-annular cutter, 4-buffer cylinder, 41-limiting ring, 4101-chute one, 42-connecting rod, 4201-chute two, 43-buffer block, 44-intercepting rod, 45-slide rod, 46-connecting block, 47-limiting block, 5-connecting frame, 6-rubber membrane. DETAILED DESCRIPTION
[0026] The above scheme is further described below with reference to specific examples. It should be understood that these examples are intended to illustrate the present application and are not intended to limit the scope of the present application. The implementation conditions used in the examples can be further adjusted according to the conditions of the specific manufacturer. The implementation conditions not specified are generally those used in routine experiments.
[0027] Example 1: Figures 1-4 As shown, an intelligent screening device for petroleum coke production includes a base 1; four shock-absorbing springs 11 are fixedly connected to the base 1; one end of all the shock-absorbing springs 11 is fixedly connected to a vibration base 12; two vibration motors 13 are installed on the vibration base 12;
[0028] It also includes a sieve cylinder 2, a feed cylinder 3 and a buffer cylinder 4; two sieve cylinders 2 are installed on the vibration seat 12 from bottom to top; a sieve mesh 21 is fixedly connected to each sieve cylinder 2; the mesh openings of different sieve meshes 21 increase from bottom to top; each sieve cylinder 2 is connected to a discharge pipe 22; a top cover 23 is fixedly connected to the top sieve cylinder 2; the feed cylinder 3 is connected to the top cover 23; the feed cylinder 3 is connected to the top sieve cylinder 2; the feed cylinder 3 is connected to the buffer cylinder 4; the buffer cylinder 4 is composed of a limit ring 41, two connecting rods 42 and a buffer block 43; the bottom surface of the limit ring 41 is in contact with the top surface of the feed cylinder 3; the connecting rod 42 is longer than the length of the feed cylinder 3; the buffer block 43 is connected to the bottom of all connecting rods 42 and is located below the feed cylinder 3.
[0029] It also includes a connecting frame 5 and a rubber membrane 6; the connecting frame 5 is welded on the base 1; the connecting frame 5 is fixedly connected to the feeding barrel 3; the rubber membrane 6 is connected to the feeding barrel 3; the rubber membrane 6 is fixedly connected to the top cover 23.
[0030] It also includes an intercepting rod 44; the buffer cylinder 4 is detachably connected to the feed cylinder 3; a plurality of intercepting rods 44 are fixedly connected to the limiting ring 41; the bottoms of all intercepting rods 44 are in contact with the buffer block 43; all intercepting rods 44 and all connecting rods 42 are arranged equidistantly in a ring.
[0031] The feeding barrel 3 further comprises an annular cutter 32 ; the bottom of the feeding barrel 3 is fixedly connected with the annular cutter 32 .
[0032] The buffer block 43 is conical in shape, so as to facilitate guiding the petroleum coke to the surrounding areas and onto the screen 21 .
[0033] A closing cover 31 is connected to the feed barrel 3; the closing cover 31 is in contact with the limiting ring 41; and is used to close the feed barrel 3 to prevent the petroleum coke powder from scattering outwards during the vibration screening process.
[0034] The closing cover 31 is embedded in the feeding barrel 3 to increase stability.
[0035] The closure cover 31 is provided with a rubber handle to facilitate the user to open and close the closure cover 31 .
[0036] Four metal pads 14 are fixed to the bottom of the base 1 to increase the contact area with the ground and improve the overall stability of the utility model.
[0037] The specific usage of this utility model is as follows:
[0038] The user places a collection container in advance at the outlet of the discharge pipe 22 corresponding to each screen drum 2, and then pours petroleum coke into the uppermost screen drum 2 through the feed drum 3. After passing through the feed drum 3, the petroleum coke will first fall on the buffer block 43. The falling force of the petroleum coke is buffered by the buffer block 43 to avoid direct impact on the screen 21 of the uppermost screen drum 2. The petroleum coke then overflows around the buffer block 43 to the screen 21 of the uppermost screen drum 2. The user then supplies power to the vibration motor 13 and starts the vibration motor 13 to drive the vibration seat 12 and all the screen drums 2 to start vibrating. The petroleum coke in the uppermost screen drum 2 will pass through the screen 21 of each screen drum 2 one by one. Petroleum coke of different sizes is intercepted by the screen 21 with corresponding hole sizes, and then moves to the outer edge of the screen 21 under the action of vibration, and is finally discharged through the discharge pipe 22 to the corresponding collection container.
[0039] During the material screening process, since the screen drum 2 is in a vibrating and shaking state, if the feed drum 3 is vibrating and shaking accordingly, it is difficult for the user to align the shaking feed drum 3 to pour the petroleum coke during feeding, and continuous screening cannot be performed during the screening process. If the diameter of the feed drum 3 is enlarged, since the petroleum coke itself contains powder particles, the powder is easy to float outward to the surface of the utility model during the pouring process, affecting the working condition of the moving parts, and the floating powder is easy to be inhaled by the user, affecting health. Therefore, the feed drum 3 of the utility model is not suitable for the user to feed the material. The barrel 3 is fixedly connected to the base 1 through the connecting frame 5. During the screening process, the vibration of the vibrating seat 12 is damped by the shock-absorbing spring 11 and is not transmitted to the base 1. The base 1 is in a stationary state, so the feed barrel 3 does not vibrate along with the sieve barrel 2, which makes it convenient for the user to pour petroleum coke into the feed barrel 3. The feed barrel 3 and the top cover 23 are connected by a rubber membrane 6. When the sieve barrel 2 vibrates, the rubber membrane 6 is deformed accordingly. The uppermost sieve barrel 2 is connected to the outside world only through the feed barrel 3. The diameter of the feed barrel 3 is small, which prevents powder from floating outward when pouring petroleum coke.
[0040] Furthermore, the sizes of the particles in the petroleum coke that needs to be screened vary greatly. The large pieces of petroleum coke have a small amplitude of movement generated by vibration and are difficult to be discharged from the discharge pipe 22 of the top screen drum 2. Therefore, a number of intercepting rods 44 are arranged between the limiting ring 41 and the buffer block 43. All intercepting rods 44 and all connecting rods 42 are arranged equidistantly in a ring. The petroleum coke poured into the feed drum 3 is first located in the buffer drum 4. The petroleum coke smaller than the gap between each intercepting rod 44 and the connecting rod 42 will be discharged from the buffer drum 4 and fall on the screen 21 of the top screen drum 2 for vibration screening, while the petroleum coke larger than the gap between each intercepting rod 44 and the connecting rod 42 will remain in the buffer drum 4, thereby performing the initial screening of the petroleum coke. For the petroleum coke remaining in the buffer drum 4, the user can grab the limiting ring 41 and lift the buffer drum 4 out of the feed drum 3 to separate the two. The user can pour out and remove the large pieces of petroleum coke screened out of the buffer drum 4, and then put the buffer drum 4 back into the feed drum 3.
[0041] Furthermore, when the user lifts the buffer tube 4 out of the feed tube 3, a portion of the large piece of petroleum coke may be stuck in the gap between the intercepting rods 44 and the connecting rods 42 and extend out of the buffer tube 4. At this time, the outer diameter of the circle surrounded by the intercepting rods 44 and the connecting rods 42 is equal to the inner diameter of the feed tube 3. The protruding portion of the petroleum coke will be blocked by the bottom surface of the feed tube 3. Therefore, an annular cutter 32 is provided on the bottom surface of the feed tube 3. The cross-section of the annular cutter 32 is a right triangle. When the buffer tube 4 is lifted out of the feed tube 3, the protruding portion of the large piece of petroleum coke will be squeezed by the annular cutter 32 and cut off by the annular cutter 32, thereby avoiding the protruding portion of the large piece of petroleum coke from being blocked by the bottom surface of the feed tube 3, affecting the lifting of the buffer tube 4 out of the feed tube 3.
[0042] It should be noted that an intelligent controller is provided on the base 1. According to the size difference of the screened petroleum coke, not only can the screen drum 2 be disassembled and the screen 21 with different mesh sizes be replaced, but the vibration amplitude of the vibration motor 13 can also be controlled by the intelligent controller to thereby change the vibration amplitude of the screen drum 2 and adjust the vibration screening speed of the petroleum coke in the screen drum 2.
[0043] According to the above description, it can be seen that the utility model has the following effects:
[0044] The petroleum coke poured into the screen drum 2 through the feed drum 3 first falls on the buffer block 43 for buffering, avoiding direct impact on the screen 21 of the uppermost screen drum 2, and preventing the impact of multiple loadings and repeated impacts on the center of the screen 21, causing the screen 21 to sag, affecting the discharge of the intercepted petroleum coke.
[0045] During the vibration screening process, the feed barrel 3 does not vibrate along with the screen barrel 2, making it easier for the user to pour the petroleum coke into the feed barrel 3; and the topmost screen barrel 2 is only connected to the outside through the feed barrel 3, which has a small aperture to prevent powder from scattering outward when pouring the petroleum coke.
[0046] The intercepting rods 44 and all the connecting rods 42 are arranged in a circular shape with equal distances. The petroleum coke poured into the feed barrel 3 is first located in the buffer barrel 4, which performs the initial screening of the large pieces of petroleum coke to prevent the large pieces of petroleum coke from falling on the screen 21 of the uppermost screen barrel 2 and being difficult to be discharged by vibration.
[0047] When the buffer tube 4 is lifted out of the feed tube 3, the portion of the large petroleum coke extending out of the buffer tube 4 will be squeezed by the annular cutter 32 and cut off by the annular cutter 32, thereby preventing the portion of the large petroleum coke extending out from the bottom surface of the feed tube 3 from being blocked and affecting the lifting of the buffer tube 4 out of the feed tube 3.
[0048] The utility model has the following additional effects:
[0049] like Figure 1 As shown, the buffer block 43 is conical, which facilitates guiding the petroleum coke on it to the surrounding areas and onto the screen 21.
[0050] like Figure 1 As shown, a closing cover 31 is connected to the feeding barrel 3. When petroleum coke is not fed, the feeding barrel 3 is closed by the closing cover 31 to prevent petroleum coke powder from floating outward through the feeding barrel 3 during the vibration screening process.
[0051] like Figure 1 As shown, four metal pads 14 are fixed to the bottom of the base 1 to increase the contact area between the base 1 and the ground and improve the overall stability of the utility model.
[0052] Example 2: Based on Example 1, Figure 4-Figure 7 As shown, it also includes a slide rod 45, a connecting block 46 and a limit block 47; each connecting rod 42 is slidably connected to a slide rod 45; each slide rod 45 is rotatably connected to a connecting block 46 at the bottom; all connecting blocks 46 are fixedly connected to the buffer block 43; two slide grooves 1 4101 are provided on the limit ring 41; each connecting rod 42 is provided with a slide groove 2 4201; each slide groove 2 4201 is connected to the adjacent slide groove 1 4101; each slide rod 45 is fixedly connected to the top of a limit block 47; the limit block 47 is located on the upper side of the limit ring 41; the limit block 47 and the slide groove 1 4101 are perpendicular to each other.
[0053] When pouring out the large pieces of petroleum coke in the buffer cylinder 4, it is necessary to tilt and invert the buffer cylinder 4. During this process, the large pieces of petroleum coke collide with each other, and the resulting pieces and powder are easy to fall out from between the connecting rod 42 and the intercepting rod 44, making it inconvenient to clean and collect. When it is necessary to pour out the large pieces of petroleum coke in the buffer cylinder 4, the buffer cylinder 4 should be tilted as shown in the figure. Figure 4 The vertical shape shown is raised from the feed barrel 3, and the large piece of petroleum coke in the buffer barrel 4 is supported by the buffer block 43. The user places the vertical buffer barrel 4 on the ground and rotates the limit block 47 ninety degrees to make it fit into the chute 1 4101. The limit block 47 drives the slide bar 45 to rotate relative to the connecting block 46. At this time, the user lifts the limit ring 41, driving the connecting rod 42 and the intercepting rod 44 to move upward. The limit block 47 will enter the chute 2 4201 through the chute 1 4101, and the connecting rod 42 moves upward relative to the slide bar 45 and the limit block 47. Figure 6As shown, the bottom of each intercepting rod 44 will be separated from the buffer block 43, so that there is no obstruction around the buffer block 43, and the large pieces of petroleum coke on the buffer block 43 can be poured out directly from between the buffer block 43 and the intercepting rod 44, without the need to invert the buffer cylinder 4, and pour the large pieces of petroleum coke out from the limit ring 41; after the petroleum coke in the buffer cylinder 4 is cleaned, the limit ring 41 is moved down again so that the bottom of the intercepting rod 44 contacts the buffer block 43, the bottom of the connecting rod 42 contacts the top surface of the connecting block 46, and the limit block 47 passes through the slide groove 4101 to the top of the limit ring 41, and then the user rotates the limit block 47 ninety degrees to dislocate it from the slide groove 4101, locks the slide rod 45 and the connecting rod 42 through the limit block 47, and the buffer cylinder 4 is restored, and then the buffer cylinder 4 is put back into the feed barrel 3.
[0054] From the above, we can know that the utility model also has the following effects: the limiting ring 41 drives the bottom of each intercepting rod 44 to separate from the buffer block 43, so that there is no obstruction around the buffer block 43, and the large pieces of petroleum coke on the buffer block 43 can be poured out directly from between the buffer block 43 and the intercepting rod 44, without the need to invert the buffer cylinder 4. The large pieces of petroleum coke are poured out from the limiting ring 41 to avoid the large pieces of petroleum coke colliding with each other during the inversion of the buffer cylinder 4. The resulting detached pieces and powder are easy to fall out from between the connecting rod 42 and the intercepting rod 44, which is inconvenient to clean and collect.
[0055] The technical principles of the embodiments of the present invention have been described above in conjunction with specific embodiments. These descriptions are intended solely to explain the principles of the embodiments of the present invention and should not be construed in any way as limiting the scope of protection of the embodiments of the present invention. Based on the explanations herein, those skilled in the art will be able to conceive of other specific implementations of the embodiments of the present invention without inventive effort, and these implementations will fall within the scope of protection of the embodiments of the present invention.
Claims
1. An intelligent screening device for petroleum coke production, comprising a base (1); a plurality of damping springs (11) fixedly connected to the base (1); a vibration base (12) fixedly connected to one end of all the damping springs (11); a plurality of vibration motors (13) mounted on the vibration base (12); wherein the device is characterized in that: The invention also includes a screen drum (2), a feed drum (3) and a buffer drum (4); a plurality of screen drums (2) are installed on the vibration seat (12) from bottom to top; a screen mesh (21) is fixedly connected to each screen drum (2); the meshes of different screen meshes (21) increase from bottom to top; each screen drum (2) is connected to a discharge pipe (22); a top cover (23) is fixedly connected to the top screen drum (2); the top cover (23) is connected to the feed drum (3); the feed drum (3) is connected to the top screen drum (2); the feed drum (3) is connected to the buffer drum (4); the buffer drum (4) is composed of a limiting ring (41), a plurality of connecting rods (42) and a buffer block (43); the bottom surface of the limiting ring (41) contacts the top surface of the feed drum (3); the connecting rod (42) is longer than the length of the feed drum (3); the buffer block (43) is connected to the bottom of all the connecting rods (42) and is located below the feed drum (3).
2. The intelligent screening equipment for petroleum coke production according to claim 1, characterized in that: It also includes a connecting frame (5) and a rubber membrane (6); the connecting frame (5) is fixedly connected to the base (1); the connecting frame (5) is fixedly connected to the feeding barrel (3); the rubber membrane (6) is connected to the feeding barrel (3); and the rubber membrane (6) is fixedly connected to the top cover (23).
3. The intelligent screening equipment for petroleum coke production according to claim 2, characterized in that: It also includes an intercepting rod (44); the buffer cylinder (4) is detachably connected to the feeding cylinder (3); a plurality of intercepting rods (44) are fixedly connected to the limiting ring (41); the bottoms of all intercepting rods (44) are in contact with the buffer block (43); all intercepting rods (44) and all connecting rods (42) are arranged in a circular shape with equal distances.
4. The intelligent screening equipment for petroleum coke production according to any one of claims 1 to 3, characterized in that: It also includes an annular cutter (32); the annular cutter (32) is fixedly connected to the bottom of the feeding barrel (3).
5. The intelligent screening equipment for petroleum coke production according to claim 4, characterized in that: The buffer block (43) is tapered.
6. The intelligent screening equipment for petroleum coke production according to claim 4, characterized in that: A closing cover (31) is connected to the feeding barrel (3); the closing cover (31) is in contact with a limiting ring (41).
7. The intelligent screening equipment for petroleum coke production according to claim 6, characterized in that: The closing cover (31) is embeddedly connected to the feeding barrel (3).
8. The intelligent screening equipment for petroleum coke production according to claim 6, characterized in that: The closing cover (31) is provided with a rubber handle.
9. The intelligent screening equipment for petroleum coke production according to claim 1, characterized in that: A plurality of metal pads (14) are fixedly connected to the bottom of the base (1).
10. The intelligent screening equipment for petroleum coke production according to claim 9, characterized in that: The invention also includes a slide rod (45), a connecting block (46) and a limit block (47); each connecting rod (42) is slidably connected to a slide rod (45); the bottom of each slide rod (45) is rotatably connected to a connecting block (46); all the connecting blocks (46) are fixedly connected to the buffer block (43); two first slide grooves (4101) are provided on the limit ring (41); a second slide groove (4201) is provided in each connecting rod (42); each second slide groove (4201) is connected to the adjacent first slide groove (4101); a limit block (47) is fixedly connected to the top of each slide rod (45); the limit block (47) is located on the upper side of the limit ring (41); the limit block (47) and the first slide groove (4101) are perpendicular to each other.