Soil turning and compacting device of plug seeder

Abstract

The soil turning and compacting device comprises an extension frame and a soil storage box, the soil storage box is fixedly connected to the upper end of a vertical plate, a discharging opening is formed in the bottom of the soil storage box, a transverse plate is fixedly connected to the position, opposite to the discharging opening, of the upper end of the soil storage box, and the transverse plate is movably connected with a transmission shaft through a bearing; the upper end of the transmission shaft is connected with an auxiliary motor through a coupler, the auxiliary motor is fixedly connected to the upper surface of the transverse plate, a penetrating opening is formed in the lower end of the side face of the extension frame, a partition plate is slidably connected into the penetrating opening, the lower end of the outer side face of the extension frame is fixedly connected with a main transmission mechanism, and the two sides of the partition plate are symmetrically connected with movable plates. Through the cooperation of the fixed frame, the extension frame, the partition plate, the servo electric cylinder and the pressing plate, the device can cover a soil layer with a proper thickness on the surface of the hole tray main body, and can perform corresponding compaction treatment on the covered soil layer, so that the seedling raising effect of seeds in the hole tray main body is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of sowing, in particular to a soil turning and compacting device of a hole tray seeder. Background Art

[0002] Plug seedling cultivation is the mainstream production method of modern agricultural production. It can quickly and massively produce vegetables and flowers. Plug seedling cultivation is to cultivate seedlings in seedling trays. It has the following advantages: saving seed usage and reducing production costs; uniform seedling emergence and maintaining the consistency of plant seedling growth; no damage to the root system during transplanting, rapid seedling acclimatization and high survival rate. Currently available plug seeders are large-scale equipment and are very expensive, which is not suitable for small-scale seedling cultivation.

[0003] After searching, a hole tray seeder disclosed in the prior art (application number: CN201710709521.8) records in the document that "the seed shaft is arranged below the upper shell of the seeder, the seed shaft rotation drive device is connected to the seed shaft, and the seed shaft rotation drive device can drive the seed shaft to rotate relative to the upper shell of the seeder to a seed loading position and a seed dropping position; the upper shell of the seeder is provided with a seed receiving hole, the inner wall of the seed receiving hole and the outer surface of the seed shaft jointly form a seed receiving cavity for holding seeds, the outer surface of the seed shaft is provided with a seed receiving countersunk hole, when the seed shaft is rotated to the seed loading position, the seed receiving countersunk hole is rotated to the right below the seed receiving hole and the seed receiving cavity and the seed receiving countersunk hole are connected to each other, and the seeds in the seed receiving cavity are At least one seed can fall into the seed-holding sink hole under the action of gravity; when the seed shaft rotates to the seed-dropping position, the seeds in the seed-holding sink hole can fall out of the seed-holding sink hole toward the position to be sown in the hole tray under the action of gravity. "; The seeder has a simple structure, convenient operation and suitable price, avoiding the situation that the existing large-scale hole tray sowing equipment is expensive and not suitable for small-scale seedling cultivation. However, after the sowing work is completed, the hole tray needs to be taken out of the hole tray sowing device and the soil covering work is completed by manpower, which makes the soil covering work inefficient and labor-intensive. In addition, manual soil covering cannot guarantee the thickness of the soil covering and the compaction effect of the soil covering, which will have a certain impact on the subsequent seedling cultivation and bring great inconvenience to the agricultural production of small farmers. Utility Model Content

[0004] In order to overcome the defects of the prior art, a soil turning and compacting device for a tray seeder is provided to solve the problems raised in the above background technology.

[0005] In order to achieve the above-mentioned purpose, a soil turning and compacting device of a hole tray seeder is provided, comprising: an extension frame and a soil storage box, the upper surface of the base is fixedly connected to the vertical plate and the conveying assembly respectively, and the hole tray body is placed on the conveyor belt of the conveying assembly, the soil storage box is fixedly connected to the upper end of the vertical plate, a discharge port is provided at the bottom of the soil storage box, and the upper end of the soil storage box is fixedly connected to a cross plate relative to the discharge port, the cross plate is movably connected to the transmission shaft through a bearing, and the upper end of the transmission shaft is connected to an auxiliary motor through a coupling, the auxiliary motor is fixedly connected to the upper surface of the cross plate, and the lower end of the transmission shaft is fixedly connected to a spiral blade, and at the same time, the lower surface of the soil storage box is fixedly connected to the fixed frame near the discharge port, a buffer groove is provided on the lower surface of the fixed frame, and the buffer groove is movably connected to the transmission shaft through a bearing The adjusting screw rod is connected, and the extension frame is slidably connected in the buffer groove through the screw-connected adjusting screw rod. A through hole is opened at the lower end of the side of the extension frame, and a partition plate is slidably connected in the through hole, and the lower end of the outer side of the extension frame is fixedly connected to the main transmission mechanism, and the movable plates are symmetrically connected on both sides of the partition plate. The movable plate is slidably connected in the storage groove opened in the extension frame, and the upper surface of the movable plate is fixedly connected to the rack, which is meshed with the circular gear of the main transmission mechanism. At the same time, the lower surface of the soil storage box is respectively fixedly connected to the servo electric cylinder and the storage column, the servo electric cylinder telescopic rod is fixedly connected to the pressure plate, and the upper surface of the pressure plate is fixedly connected to the extension rod, and the upper end of the extension rod is slidably connected to the storage cavity opened in the storage column through a limit plate, and the limit ring is screwed to the outer side of the storage column.

[0006] Preferably, the bottom of the inner cavity of the soil storage box is fixedly connected to an auxiliary block, the cross-section of the auxiliary block is a right-angled triangle structure, and the inner side surface of the soil storage box is fixedly connected to a support plate relative to the transmission shaft, the suspended end of the support plate is movably connected to the transmission shaft through a sealed bearing, and the cross plate is movably connected to the two groups of transmission shafts, and the upper ends of the two groups of transmission shafts are fixedly connected to pulleys, and the two groups of pulleys are connected by belts.

[0007] Preferably, the fixed frame is in the shape of a square cylinder, and the buffer groove opened on the lower surface of the fixed frame is in the shape of a U-shaped structure, and the sizes of the buffer groove and the extension frame are adapted to each other, and the upper end of the adjusting screw is located in the transmission groove opened in the fixed frame, and at the same time, the side of the transmission groove is movably connected to the adjusting rod through a bearing, and the adjusting rod is connected to the adjusting screw through a bevel gear.

[0008] Preferably, the extension frame is in a square cylindrical structure, with scale lines on the outer side of the extension frame, and a through opening on the lower surface of the extension frame is in a long strip structure, and the size of the through opening and the partition plate are adapted, and the fixed plate is in a rectangular structure.

[0009] Preferably, the main transmission mechanism consists of a dual-axis motor, a transmission rod and a circular gear. The dual-axis motor is fixedly connected to the outer side of the extension frame, and both ends of the dual-axis motor are connected to the transmission rod through a coupling, and the transmission rod is movably connected to the outer side of the extension frame through a bearing, and at the same time, one end of the transmission rod away from the dual-axis motor is fixedly connected to the circular gear.

[0010] Preferably, the moving plate has an F-shaped structure. The groove formed on the upper surface of the moving plate is in a strip-shaped structure. The size of the groove is adapted to that of the rack. The bent end of the moving plate is fixedly connected to the partition plate. At the same time, one end of the lower surface of the partition plate located within the extension frame is fixedly connected to the limiting block, and the limiting block is in a strip-shaped structure.

[0011] Preferably, the pressing plate has a rectangular structure. Four groups of extension rods are symmetrically connected to the upper surface of the pressing plate. The extension rods and the receiving columns are both in a cylindrical structure. The axial section formed by the combination of the receiving column and the receiving cavity is in a "冂"-shaped structure. Two groups of limiting grooves are symmetrically formed on both sides of the receiving cavity. The length of the limiting groove is less than that of the receiving cavity. At the same time, the limiting plate fixedly connected to the upper end of the extension rod is in a strip-shaped structure, and both ends of the limiting plate are slidably connected within the limiting grooves.

[0012] Compared with the prior art, the beneficial effects of the present utility model are as follows: Through the cooperation of the soil storage box, the fixed frame, the extension frame, the adjusting screw rod, the main transmission mechanism, the moving plate and the partition plate, the device can cover a soil layer with a suitable thickness on the surface of the seedling tray body. Through the cooperation of the servo electric cylinder and the pressing plate, the soil layer on the surface of the seedling tray body can be subjected to corresponding compaction treatment, thereby effectively improving the efficiency of the soil covering work on the surface of the seedling tray body, reducing the labor intensity, and ensuring normal seedling raising in the follow-up. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a front view schematic diagram of an embodiment of the present utility model.

[0014] Figure 2 It is a side view schematic diagram of an embodiment of the present utility model.

[0015] Figure 3 It is a partial top view schematic diagram of the extension frame of an embodiment of the present utility model.

[0016] Figure 4 It is a sectional structure schematic diagram of the receiving column of an embodiment of the present utility model.

[0017] In the figure: 1, base; 2, conveying assembly; 3, seedling tray body; 4, partition plate; 5, main transmission mechanism; 6, extension frame; 7, adjusting screw rod; 8, fixed frame; 9, soil storage box; 10, transmission shaft; 11, cross plate; 12, wheel disc; 13, auxiliary motor; 14, servo electric cylinder; 15, receiving column; 16, limiting plate; 17, extension rod; 18, limiting ring; 19, pressing plate; 20, vertical plate; 21, moving plate. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] Refer to Figures 1 to 4As shown, the utility model provides a soil turning and compacting device for a hole tray seeder, comprising: an extension frame 6 and a soil storage box 9, the upper surface of the base 1 is fixedly connected to the vertical plate 20 and the conveying assembly 2 respectively, and the hole tray body 3 is placed on the conveyor belt of the conveying assembly 2, the soil storage box 9 is fixedly connected to the upper end of the vertical plate 20, a discharge port is provided at the bottom of the soil storage box 9, and the upper end of the soil storage box 9 is fixedly connected to the transverse plate 11 relative to the discharge port, the transverse plate 11 is movably connected to the transmission shaft 10 through a bearing, and the upper end of the transmission shaft 10 is connected to the auxiliary motor 13 through a coupling, the auxiliary motor 13 is fixedly connected to the upper surface of the transverse plate 11, and the lower end of the transmission shaft 10 is fixedly connected to the spiral blade, and at the same time, the lower surface of the soil storage box 9 is fixedly connected to the fixed frame 8 near the discharge port, and a buffer groove is provided on the lower surface of the fixed frame 8, and the buffer groove is movably connected and adjusted through the bearing The screw rod 7, and the extension frame 6 is slidably connected in the buffer groove through the screw-connected adjustment screw rod 7, the lower end of the side of the extension frame 6 is provided with a through hole, the partition plate 4 is slidably connected in the through hole, and the lower end of the outer side of the extension frame 6 is fixedly connected to the main transmission mechanism 5, and the partition plate 4 is symmetrically connected to the movable plate 21 on both sides, the movable plate 21 is slidably connected in the storage groove opened in the extension frame 6, the upper surface of the movable plate 21 is fixedly connected to the rack, the rack is meshed with the circular gear of the main transmission mechanism 5, and at the same time, the lower surface of the soil storage box 9 is respectively fixedly connected to the servo electric cylinder 14 and the storage column 15, the telescopic rod of the servo electric cylinder 14 is fixedly connected to the pressure plate 19, and the upper surface of the pressure plate 19 is fixedly connected to the extension rod 17, the upper end of the extension rod 17 is slidably connected to the storage cavity opened in the storage column 15 through the limit plate 16, and the limit ring 18 is screwed to the outer side of the storage column 15.

[0019] The conveyor belt drives the main body 3 of the hole tray 3 to move to the bottom of the soil storage box 9, and the switch of the conveyor assembly 2 is started. The main body 3 of the hole tray 3 is driven by the conveyor belt to move to the bottom of the soil storage box 9, and the switch of the double-axis motor in the main transmission mechanism 5 is started. The double-axis motor drives the transmission rod and the circular gear to rotate synchronously through the coupling, and the circular gear drives the movable plate 21 and the partition plate 4 to move synchronously through the meshing rack, so that the lower end opening of the extension frame 6 is opened, so that the soil stored in the soil storage box 9 can slide smoothly onto the surface of the hole tray main body 3, wherein, according to the thickness of the soil layer required to cover the surface of the hole tray main body 3, the worker rotates the adjusting screw rod 7 through the adjusting rod, and the adjusting screw rod 7 pushes the screw-connected extension frame 6 to move, and the worker can confirm the moving distance of the extension frame 6 in real time through the scale line on the surface of the extension frame 6, to ensure that the surface of the hole tray main body 3 can be covered with a soil layer of appropriate thickness, and during the low-speed movement of the hole tray main body 3 , the soil can be evenly covered on the surface of the hole tray body 3. After the surface of the hole tray body 3 is covered, the reset switch of the main transmission mechanism 5 is started, and then the main transmission mechanism 5 can push the partition plate 4 to reset, and close the switch at the lower end of the extension frame 6 to reduce the probability of soil spilling. When the hole tray body 3 moves to just below the pressure plate 19, the switch of the conveying component 2 is turned off, and the switch of the servo electric cylinder 14 is started. The telescopic rod of the servo electric cylinder 14 pushes the pressure plate 19 down to a preset distance, and then completes the compaction operation of the soil layer on the surface of the hole tray body 3, thereby ensuring that the hole tray body 3 can be normally raised seedlings later. Among them, the switch of the auxiliary motor 13 is started, and the auxiliary motor 13 drives a group of transmission shafts 10 to rotate through the coupling, and the transmission shaft 10 can drive another group of transmission shafts 10 to rotate synchronously through the cooperation of the wheel plate 12 and the belt, so that the two groups of spiral blades can rotate synchronously in the fixed frame 8, thereby improving the smoothness of soil falling.

[0020] As a preferred embodiment, the bottom of the inner cavity of the soil storage box 9 is fixedly connected to an auxiliary block, the cross-section of the auxiliary block is a right-angled triangle structure, and the inner side of the soil storage box 9 is fixedly connected to a support plate relative to the position of the transmission shaft 10. The suspended end of the support plate is movably connected to the transmission shaft 10 through a sealed bearing. At the same time, the cross plate 11 is movably connected to the two groups of transmission shafts 10. The upper ends of the two groups of transmission shafts 10 are fixedly connected to the pulleys 12, and the two groups of pulleys 12 are connected by belts.

[0021] In this embodiment, if Figure 1 and Figure 2 The inclined structure of the auxiliary block can assist the soil in the soil storage box 9 to fall, and the setting of the support plate can assist in enhancing the stability of the transmission shaft 10 and the spiral blade during rotation.

[0022] As a preferred embodiment, the fixed frame 8 is in the shape of a square cylinder, and the buffer groove provided on the lower surface of the fixed frame 8 is in the shape of a U-shaped structure, and the sizes of the buffer groove and the extension frame 6 are adapted to each other, and the upper end of the adjusting screw 7 is located in the transmission groove provided in the fixed frame 8, and at the same time, the side of the transmission groove is movably connected to the adjusting rod through a bearing, and the adjusting rod is connected to the adjusting screw 7 through a bevel gear.

[0023] In this embodiment, if Figure 1 , Figure 2 and Figure 3 The sizes of the buffer groove and the extension frame 6 are matched, which can help enhance the stability of the extension plate when it moves, and the extension frame 6 can be made of lightweight plastic according to actual needs, thereby reducing the weight of the adjusting screw 7, and the lower end of the outer side of the fixed frame 8 is screwed with a fastening bolt, which can help enhance the fixing effect between the fixed frame 8 and the extension frame 6.

[0024] As a preferred embodiment, the extension frame 6 is a square cylindrical structure, with scale lines on the outer side of the extension frame 6, and the through opening on the lower surface of the extension frame 6 is a long strip structure, and the size of the through opening and the partition plate 4 are adapted, and the fixed plate is a rectangular structure.

[0025] In this embodiment, if Figure 1 , Figure 2 and Figure 3 The scale lines on the outer side of the extension frame 6 can help workers grasp the moving distance of the extension frame 6 in real time, which can then help improve the accuracy of the soil thickness on the surface of the hole tray body 3. At the same time, the sizes of the through-hole and the partition board 4 are matched, which can help enhance the stability of the partition board 4 when it moves.

[0026] As a preferred embodiment, the main transmission mechanism 5 is composed of a dual-axis motor, a transmission rod and a circular gear. The dual-axis motor is fixedly connected to the outer side of the extension frame 6, and the two ends of the dual-axis motor are connected to the transmission rod through a coupling, and the transmission rod is movably connected to the outer side of the extension frame 6 through a bearing. At the same time, the end of the transmission rod away from the dual-axis motor is fixedly connected to the circular gear.

[0027] In this embodiment, if Figure 1 , Figure 2 and Figure 3 The setting of the main transmission mechanism 5 enables the movable plate 21 to drive the partition plate 4 to perform corresponding reciprocating movement, thereby reducing the probability of accidental scattering of soil in the soil storage box 9 and improving the convenience of opening and closing the lower end of the extension frame 6.

[0028] As a preferred embodiment, the moving plate 21 has an F-shaped structure. The groove formed on the upper surface of the moving plate 21 has a strip-shaped structure. The size of the groove is adapted to that of the rack. The bent end of the moving plate 21 is fixedly connected to the partition plate 4. At the same time, one end of the lower surface of the partition plate 4 located within the extension frame 6 is fixedly connected to a limit block, and the limit block has a strip-shaped structure.

[0029] In this embodiment, as Figure 2 and Figure 3 shown, the arrangement of the moving plate 21 can drive the partition plate 4 to move synchronously, can also assist in enhancing the stability of the partition plate 4 during movement, can further reduce the probability of movement failure of the partition plate 4. At the same time, the arrangement of the limit block can prevent the partition plate 4 from accidentally disengaging from the through hole opened in the extension frame 6.

[0030] As a preferred embodiment, the pressing plate 19 has a rectangular structure. Four groups of extension rods 17 are symmetrically connected to the upper surface of the pressing plate 19. Both the extension rods 17 and the receiving columns 15 have a cylindrical structure. The axial section formed by the combination of the receiving column 15 and the receiving cavity has an inverted U-shaped structure. Two groups of limit grooves are symmetrically opened on both sides of the receiving cavity. The length of the limit grooves is less than the length of the receiving cavity. At the same time, the limit plate 16 fixedly connected to the upper end of the extension rod 17 has a strip-shaped structure, and both ends of the limit plate 16 are slidably connected in the limit grooves.

[0031] In this embodiment, as Figure 1 and Figure 4 shown, scale lines are provided on the outer side surface of the receiving column 15. Then, by adjusting the position of the limit ring 18, the movement range of the limit plate 16 can be correspondingly restricted, and further the movement range of the extension rod 17 can be restricted, so as to realize the auxiliary adjustment of the stroke accuracy of the servo electric cylinder 14, and ensure that the soil layer on the surface of the seedling tray main body 3 can be compacted to an appropriate degree.

[0032] Through the cooperation of the soil turning and compacting device of the seedling tray seeding machine of the present utility model, namely the fixed frame 8, the extension frame 6, the partition plate 4, the servo electric cylinder 14 and the pressing plate 19, the device can cover a soil layer with an appropriate thickness on the surface of the seedling tray main body 3, and can perform corresponding compaction treatment on the covered soil layer, so as to ensure the seedling raising effect of the seeds in the seedling tray main body 3, effectively reduce the labor intensity of workers, improve the efficiency of soil covering and compaction of the seedling tray main body 3, and thus assist in improving the working efficiency of the seedling tray seeding machine.

Claims

1. A soil turning and compacting device for a tray seeder, comprising: The extension frame (6) and the soil storage box (9), the upper surface of the base (1) is fixedly connected to the vertical plate (20) and the conveying component (2), and the hole tray body (3) is placed on the conveying belt of the conveying component (2), characterized in that: the soil storage box (9) is fixedly connected to the upper end of the vertical plate (20), a discharge port is provided at the bottom of the soil storage box (9), and the upper end of the soil storage box (9) is fixedly connected to the transverse plate (11) relative to the discharge port, the transverse plate (11) is movably connected to the transmission shaft (10) through a bearing, and the upper end of the transmission shaft (10) is connected to the auxiliary motor (13) through a coupling, the auxiliary motor (13) is fixedly connected to the upper surface of the transverse plate (11), and the lower end of the transmission shaft (10) is fixedly connected to the spiral blade, and at the same time, the lower surface of the soil storage box (9) is fixedly connected to the fixed frame (8) near the discharge port, and a buffer groove is provided on the lower surface of the fixed frame (8), and the buffer groove is movably connected to the adjusting screw rod (7) through a bearing, and the extension frame (6) is connected to the fixed frame (8) through a bearing. The screw-connected adjusting screw rod (7) is slidably connected in the buffer groove, the lower end of the side surface of the extension frame (6) is provided with a through hole, the partition plate (4) is slidably connected in the through hole, and the lower end of the outer side surface of the extension frame (6) is fixedly connected to the main transmission mechanism (5), and the two sides of the partition plate (4) are symmetrically connected to the moving plate (21), the moving plate (21) is slidably connected in the storage groove provided in the extension frame (6), and the upper surface of the moving plate (21) is fixedly connected to the rack, and the rack is connected to the main transmission mechanism. The circular gears of the mechanism (5) are meshed, and at the same time, the lower surface of the soil storage box (9) is fixedly connected to the servo electric cylinder (14) and the storage column (15), respectively. The telescopic rod of the servo electric cylinder (14) is fixedly connected to the pressure plate (19), and the upper surface of the pressure plate (19) is fixedly connected to the extension rod (17). The upper end of the extension rod (17) is slidably connected to the storage cavity opened by the storage column (15) through the limit plate (16), and the limit ring (18) is screwed to the outer side of the storage column (15).

2. The soil turning and compacting device of a tray seeder according to claim 1, characterized in that: The bottom of the inner cavity of the soil storage box (9) is fixedly connected to an auxiliary block, the cross section of the auxiliary block is a right-angled triangle structure, and the inner side surface of the soil storage box (9) is fixedly connected to a support plate at a position relative to the transmission shaft (10), the suspended end of the support plate is movably connected to the transmission shaft (10) through a sealed bearing, and the cross plate (11) is movably connected to the two groups of transmission shafts (10), the upper ends of the two groups of transmission shafts (10) are fixedly connected to a wheel disc (12), and the two groups of wheel discs (12) are connected by a belt.

3. The soil turning and compacting device of a tray seeder according to claim 1, characterized in that: The fixed frame (8) is in a square cylindrical structure, and the buffer groove provided on the lower surface of the fixed frame (8) is in a square-shaped structure, and the sizes of the buffer groove and the extension frame (6) are matched, and the upper end of the adjusting screw rod (7) is located in the transmission groove provided in the fixed frame (8), and the side of the transmission groove is movably connected to the adjusting rod through a bearing, and the adjusting rod is connected to the adjusting screw rod (7) through a bevel gear.

4. The soil turning and compacting device of a tray seeder according to claim 1, characterized in that: The extension frame (6) is in the form of a square tube, a scale line is provided on the outer side of the extension frame (6), and a through opening provided on the lower surface of the extension frame (6) is in the form of a long strip, and the size of the through opening and the partition plate (4) are adapted, while the fixed plate is in the form of a rectangular structure.

5. The soil turning and compacting device of a tray seeder according to claim 1, characterized in that: The main transmission mechanism (5) is composed of a double-shaft motor, a transmission rod and a circular gear. The double-shaft motor is fixedly connected to the outer side surface of the extension frame (6), and both ends of the double-shaft motor are connected to the transmission rod through couplings. The transmission rod is movably connected to the outer side surface of the extension frame (6) through bearings. At the same time, the end of the transmission rod away from the double-shaft motor is fixedly connected to the circular gear.

6. The soil turning and compacting device of a tray seeder according to claim 1, characterized in that: The moving plate (21) has an F-shaped structure. The groove formed on the upper surface of the moving plate (21) has a long strip structure, and the size of the groove is adapted to that of the rack. The bent end of the moving plate (21) is fixedly connected to the partition plate (4). At the same time, one end of the lower surface of the partition plate (4) located inside the extension frame (6) is fixedly connected to a limiting block, and the limiting block has a long strip structure.

7. The soil turning and compacting device of a tray seeder according to claim 1, characterized in that: The pressing plate (19) has a rectangular structure. Four groups of extension rods (17) are symmetrically connected to the upper surface of the pressing plate (19). Both the extension rod (17) and the receiving column (15) have a cylindrical structure. The axial section formed by the combination of the receiving column (15) and the receiving cavity has an inverted U-shaped structure. Two groups of limiting grooves are symmetrically formed on both sides of the receiving cavity, and the length of the limiting groove is less than the length of the receiving cavity. At the same time, the limiting plate (16) fixedly connected to the upper end of the extension rod (17) has a long strip structure, and both ends of the limiting plate (16) are slidably connected in the limiting grooves.

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