Flexible self-adapting ball core orifice rounding polishing device

Abstract

This application discloses a flexible adaptive ball core orifice rounding grinding device. The ball core is located on an electric turntable and clamped by manual jaws. Starting the longitudinal motor drives the longitudinal lead screw to rotate, realizing the vertical movement of the longitudinal guide column. Starting the transverse motor drives the transverse lead screw to rotate, realizing the horizontal movement of the transverse guide column. With the longitudinal and transverse lead screws linked, the grinder can move up and down and left and right, and be positioned. Starting the drive motor drives the gear to rotate, which in turn drives the lifting rod to move up and down via the rack. At this time, the lifting rod can smoothly slide along the slide groove at the rear end of the grinder, thereby causing the grinder to swing around the axis. After the electric turntable rotates at a set speed, it works in conjunction with the grinder to achieve uniform grinding and polishing of the rounded corners of the ball core orifice. By changing the abrasive belts of different grits, the automated and flexible grinding and polishing of the ball core orifice can be completed according to process requirements, effectively improving product quality and production efficiency, and reducing production costs.

Description

Technical Field

[0001] This utility model relates to the field of ball core processing technology, and in particular to a flexible adaptive ball core orifice rounding grinding device. Background Technology

[0002] The rounded corners of the ball valve orifice play a crucial role in reducing stress concentration, optimizing fluid flow, preventing cracks and defects, enhancing structural strength, and improving assembly and debugging convenience. However, after using additive manufacturing processes such as spraying and cladding, the rounded corners of the ball valve orifice become uneven due to the adhered coating material. If these orifices are not polished, the fluid passing through the sharp edges will generate severe eddies and turbulence, leading to significant flow resistance and pressure drop. When the ball valve is subjected to internal fluid pressure, especially circulating pressure and impact loads, the stress at this point will increase sharply, making it highly susceptible to microcracks. Currently, the rounded corners of the ball valve orifice are typically polished manually using handheld power tools. However, this polishing method cannot guarantee the roughness and consistency of the rounded corners, and the work efficiency is extremely low. Utility Model Content

[0003] The purpose of this application is to provide a flexible adaptive ball core orifice rounding grinding device to solve the problems that the roughness and consistency of the ball core orifice rounding cannot be guaranteed and the work efficiency is low after using traditional manual hand-held power tools to grind the ball core orifice rounding.

[0004] To address the aforementioned technical problems, this application provides a flexible adaptive ball core orifice rounding grinding device, comprising: The base plate has an electric turntable mounted on it via a support column. The electric turntable is driven by a motor installed at the upper end of the support column. The electric turntable is equipped with a manual chuck. The ball core is located on the electric turntable and is clamped by the manual chuck. A grinder is provided at the opening of the ball core. A mounting bracket is fixed to one side of the base plate. The mounting bracket is equipped with a longitudinal lead screw driven by a longitudinal motor and a longitudinal guide post slidably connected to the mounting bracket. The longitudinal guide post is threadedly connected to the longitudinal lead screw. A transverse lead screw driven by a transverse motor is installed through a mounting groove at the crossbeam of the longitudinal guide post. A transverse guide post is threadedly connected to the transverse lead screw. A rack and a gear meshing with the rack are threaded through the transverse guide post. The gear is driven by a drive motor mounted on the transverse guide post. A connecting sleeve is slidably mounted on the lower end of the rack via a column rod. A lifting rod is mounted on the connecting sleeve. The lifting rod is located in a groove at the rear end of the grinder. One end of the rotating shaft in the middle of the grinder is located in a bearing hole at the lower part of the transverse guide post. A grinding rod is mounted on the front end of the grinder via an elastic component. A roller located at the ball core opening is rotatably mounted on the front end of the grinding rod. An abrasive belt is provided between the roller and the main roller of the grinder.

[0005] In a preferred embodiment, a flexible adaptive ball core orifice rounding grinding device is provided. The mounting frame includes a support plate, and a mounting plate is fixed to the outer side of the support plate. The mounting plate is provided with a vertical mounting hole. A longitudinal lead screw is rotatably mounted in the vertical mounting hole. A longitudinal motor is fixed to the lower side of the mounting plate and its output shaft is fixedly connected to the lower end of the longitudinal lead screw. A through hole is provided on the longitudinal guide post, and the longitudinal guide post is slidably connected to the mounting plate through the through hole.

[0006] The solution requires detailed explanation of a flexible adaptive ball core orifice rounding grinding device, wherein a limiting hole is provided on one side of the transverse guide post, and the outer edge of the mounting groove is located within the limiting hole.

[0007] As a preferred embodiment, a flexible adaptive ball core orifice rounding grinding device is provided, wherein a guide pin is fixed at the lower end of the column rod; Correspondingly, the connecting sleeve is provided with a sliding groove that extends through the bottom, and both ends of the guide pin are located within the sliding groove.

[0008] The solution requires further detailed explanation of a flexible adaptive ball core orifice rounding grinding device, wherein a buffer spring is also provided at the lower part of the column rod, and the lower part of the buffer spring is located inside the connecting sleeve.

[0009] As a preferred embodiment, a flexible adaptive ball core orifice rounding grinding device is provided, wherein the elastic component includes a limiting slide groove disposed at the front end of the grinder, a spring is installed in the limiting slide groove, and the other end of the spring is connected to the grinding rod.

[0010] The solution requires further detailed explanation of a flexible adaptive ball core orifice rounding grinding device, wherein a slot is provided on the inner side wall of the limiting slide groove, and correspondingly, a raised flat key is provided on the grinding rod, the raised flat key being located in the slot.

[0011] Compared with the prior art, the flexible adaptive ball core orifice rounding grinding device provided by this utility model includes a base plate, on which an electric turntable is mounted via a support column. The electric turntable is driven by a motor mounted on the upper end of the support column. A manual chuck is mounted on the electric turntable. The ball core is located on the electric turntable and clamped by the manual chuck. A grinder is installed at the orifice of the ball core. A mounting frame is fixed to one side of the base plate. A longitudinal lead screw driven by a longitudinal motor and a longitudinal guide post slidably connected to the mounting frame are mounted on the mounting frame. The longitudinal guide post is threadedly connected to the longitudinal lead screw. Starting the longitudinal motor can drive the longitudinal lead screw to rotate. The longitudinal guide column is raised and lowered. A transverse screw, driven by a transverse motor, is installed in the crossbeam of the longitudinal guide column via a mounting slot. The transverse guide column is threaded onto the transverse screw. A rack and a gear meshing with the rack are threaded through the transverse guide column. The gear is driven by a drive motor mounted on the transverse guide column. A connecting sleeve is slidably mounted on the lower end of the rack via a column rod. A lifting rod is mounted on the connecting sleeve and is located in a groove at the rear end of the grinder. Activating the transverse motor rotates the transverse screw, enabling the transverse guide column to move left and right. When the longitudinal and transverse screws are linked, the grinder can move up and down, left and right, and be positioned. One end of the rotating shaft in the middle of the grinder is located in a bearing hole at the lower part of the transverse guide column. A grinding rod is mounted at the front end of the grinder via an elastic component. A roller located at the ball core hole is rotatably mounted at the front end of the grinding rod. An abrasive belt is positioned between the roller and the main roller of the grinder. Starting the drive motor rotates the gears, which in turn drive the lifting rod up and down via the rack. As the lifting rod moves up and down, it slides smoothly along the groove at the rear of the grinder, causing the grinder to oscillate around its axis. The electric turntable rotates at a set speed, working in conjunction with the grinder to achieve uniform grinding and polishing of the rounded corners of the ball core openings. By changing the abrasive belts of different grits, automated and flexible grinding and polishing of the ball core openings can be completed according to process requirements. The adaptive structure of this device makes the grinding force gentler, resulting in higher surface quality. It also supports one person operating multiple machines simultaneously, effectively improving product quality and production efficiency while reducing production costs. Attached Figure Description

[0012] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0013] Figure 1This is a schematic diagram of a flexible adaptive ball core orifice rounding grinding device provided in an embodiment of this application; Figure 2 This is a schematic diagram of a longitudinal guide post structure provided in an embodiment of this application; Figure 3 This is a schematic diagram of a transverse guide post structure provided in an embodiment of this application; Figure 4 This is a schematic diagram of an electric turntable structure provided in an embodiment of this application; Figure 5 This is a schematic diagram of the connection between a grinder and a lifting rod provided in an embodiment of this application; Figure 6 An exploded view of the connection between a grinding rod and a grinding tool provided in an embodiment of this application; In the diagram: 1. Base plate; 2. Support column; 3. Electric turntable; 4. Manual chuck; 5. Ball core; 6. Grinding tool; 60. Limiting groove; 600. Slot; 61. Spring; 62. Grinding motor; 7. Mounting bracket; 70. Support plate; 71. Mounting plate; 72. Vertical mounting hole; 8. Longitudinal motor; 9. Longitudinal lead screw; 10. Longitudinal guide post; 100. Through hole; 11. Mounting slot; 12. Transverse lead screw; 120. Transverse motor; 13. Transverse guide post; 130. Limiting hole; 14. Rack; 15. Gear; 16. Drive motor; 17. Column; 170. Guide pin; 18. Connecting sleeve; 180. Sliding groove; 19. Lifting rod; 20. Sliding groove; 21. Shaft; 22. Bearing hole; 23. Grinding rod; 230. Raised flat key; 24. Roller; 25. Sanding belt; 26. Buffer spring. Detailed Implementation

[0014] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0015] The core of this application is to provide a flexible adaptive ball core orifice rounding grinding device, which solves the problem that the roughness and consistency of the ball core orifice rounding cannot be guaranteed and the work efficiency is low after using traditional manual hand-held power tools to grind the ball core orifice rounding.

[0016] Figure 1 This is a schematic diagram of a flexible adaptive ball core orifice rounding grinding device provided in an embodiment of this application. Figure 2 This is a schematic diagram of a longitudinal guide post structure provided in an embodiment of this application. Figure 3 This is a schematic diagram of a transverse guide post structure provided in an embodiment of this application. Figure 4 This is a schematic diagram of an electric turntable structure provided in an embodiment of this application. Figure 5This is a schematic diagram of the connection between a grinder and a lifting rod provided in an embodiment of this application. Figure 6 An exploded view of the connection between a grinding rod and a grinding tool provided in an embodiment of this application is shown below. Figures 1 to 6 As shown.

[0017] Example 1 A flexible adaptive ball core orifice rounding grinding device includes a base plate 1. An electric turntable 3 is mounted on the base plate 1 via a support column 2. The electric turntable 3 is driven by a motor mounted on the upper end of the support column 2 (the motor is not shown in the figure). The connection relationship between the electric turntable 3 and the motor, as well as the working principle, can be determined according to actual conditions. Manual chucks 4 are mounted radially on the electric turntable 3. The structure and working principle of the manual chucks 4 can be found in existing technology. The ball core 5 is located on the electric turntable 3, and different specifications of ball cores 5 are quickly positioned and clamped via the manual chucks 4. A grinder 6 is installed at the orifice of the ball core 5; the grinder 6 can grind and polish the rounded corners of the orifice of the ball core 5.

[0018] A mounting bracket 7 is fixed to one side of the base plate 1. A longitudinal lead screw 9 is mounted on the mounting bracket 7. The longitudinal lead screw 9 is driven by a longitudinal motor 8 fixed to the mounting bracket 7. A longitudinal guide post 10 is slidably connected to the mounting bracket 7. The longitudinal guide post 10 is threadedly connected to the longitudinal lead screw 9. Starting the longitudinal motor 8 can drive the longitudinal lead screw 9 to rotate, thereby realizing the up and down movement of the longitudinal guide post 10 and adjusting the grinding height of the grinder 6. A bottom-through mounting groove 11 is provided at the crossbeam of the longitudinal guide post 10. A transverse lead screw 12 is rotatably mounted in the mounting groove 11. The transverse lead screw 12 is driven by a transverse motor 120 fixedly mounted on one side of the longitudinal guide post 10. A transverse guide post 13 is threadedly connected to the transverse lead screw 12. Starting the transverse motor 120 can drive the transverse lead screw 12 to rotate, realizing the left and right movement of the transverse guide post 13. After the longitudinal lead screw 9 and the transverse lead screw 12 are linked, the grinder 6 can move up and down and left and right and be positioned, which is convenient for grinding the rounded corner of the hole of the ball core 5.

[0019] A rack 14 and a gear 15 that meshes with the rack 14 are installed through the transverse guide post 13. The gear 15 is driven by a drive motor 16 installed on the transverse guide post 13. A connecting sleeve 18 is slidably installed on the lower end of the rack 14 through a column rod 17. A lifting rod 19 is installed on the connecting sleeve 18. The lifting rod 19 is located in the groove 20 at the rear end of the grinder 6. One end of the rotating shaft 21 in the middle of the grinder 6 is located in the bearing hole 22 at the lower part of the transverse guide post 13. A grinding rod 23 is installed at the front end of the grinder 6 through an elastic component. A roller 24 located at the hole of the ball core 5 is rotatably installed at the front end of the grinding rod 23. A sanding belt 25 is provided between the roller 24 and the main roller of the grinder 6. The sanding belt 25 is limited and installed by the belt groove provided on the main roller of the grinder 6 through the roller 24. Starting the drive motor 16 can drive the gear 15 to rotate, which in turn drives the lifting rod 19 to move up and down through the rack 14. When the lifting rod 19 moves up and down, it can slide smoothly along the slide groove 20 at the rear end of the grinder 6, thereby driving the grinder 6 to swing around the rotating shaft 21. During this process, the grinding motor 62 drives the sanding belt 25 to run, and the sanding belt 25 grinds and polishes the rounded corner of the ball core 5 hole. In actual use, the electric turntable 3 can be controlled to rotate at a set speed and then cooperate with the grinder 6 to achieve uniform grinding and polishing of the rounded corner of the ball core 5 hole.

[0020] Example 2 Based on Embodiment 1, a flexible adaptive ball core orifice rounding grinding device is provided. To facilitate the installation of the longitudinal lead screw 9, preferably, the mounting frame 7 includes a support plate 70, with a mounting plate 71 fixed to the outer side of the support plate 70. The mounting plate 71 has a vertical mounting hole 72, in which the longitudinal lead screw 9 is rotatably mounted. A longitudinal motor 8 is fixed to the lower side of the mounting plate 71, and its output shaft is fixedly connected to the lower end of the longitudinal lead screw 9. A through hole 100 is provided on the longitudinal guide post 10, which is slidably connected to the mounting plate 71 via the through hole 100. During the rotation of the longitudinal lead screw 9, which drives the longitudinal guide post 10 to move up and down, the mounting plate 71 and the through hole 100 can be used to limit the movement of the longitudinal guide post 10.

[0021] Based on Embodiment 1, a flexible adaptive ball core orifice rounding grinding device is provided. In order to facilitate the limiting of the transverse guide post 13, a limiting hole 130 is preferably provided on one side of the transverse guide post 13, and the outer edge of the mounting groove 11 is located inside the limiting hole 130. During the process of the transverse screw 12 rotating and driving the transverse guide post 13 to move along the crossbeam, the limiting hole 130 and the mounting groove 11 can cooperate to limit the transverse guide post 13, so as to prevent the transverse guide post 13 from rotating with the transverse screw 12.

[0022] Based on Embodiment 1, a flexible adaptive ball core orifice rounding grinding device is provided, wherein a guide pin 170 is fixed at the lower end of the column rod 17; correspondingly, a sliding groove 180 with a bottom through-hole is provided on the connecting sleeve 18, and both ends of the guide pin 170 are located in the sliding groove 180. The cooperation between the guide pin 170 and the sliding groove 180 ensures that the lifting rod 19 installed on the connecting sleeve 18 is always perpendicular to the grinder 6 and will not rotate, thus ensuring effective grinding operation.

[0023] In this embodiment, a flexible adaptive ball core orifice rounding grinding device includes a buffer spring 26 at the lower part of the column rod 17, with the lower part of the buffer spring 26 located inside the connecting sleeve 18. When the rack 14 drives the lifting rod 19 to move up and down, the buffer spring 26 can effectively buffer the load force exceeding the load indirectly transmitted by the grinder 6, adapting to the uneven surface of the ball core 5 orifice after additive manufacturing, and the irregular stress generated during grinding. Simultaneously, during this process, the guide pin 170 can slide relative to the sliding groove 180.

[0024] Based on Embodiment 1, a flexible adaptive ball core orifice rounding grinding device includes an elastic component comprising a limiting slide groove 60 disposed at the front end of the grinder 6, a spring 61 installed within the limiting slide groove 60, and the other end of the spring 61 connected to the grinding rod 23. In this embodiment, a flexible adaptive ball core orifice rounding grinding device further includes a retaining groove 600 on the inner sidewall of the limiting slide groove 60, and correspondingly, a raised flat key 230 is provided on the grinding rod 23, the raised flat key 230 being located within the retaining groove 600. The coordinated use of the raised flat key 230 and the slot 600 ensures that the grinding rod 23 will not rotate during grinding. The spring 61 can apply preload, facilitating the tensioning or compression of the sanding belt 25. When the grinder 6 is grinding at the opening of the ball core 5, the sanding belt 25 will elastically bend inward due to the force. At this time, the spring 61 can balance the unbalanced force during grinding, causing the grinding rod 23 to move backward along the central axis of the grinder 6 shaft hole to accommodate grinding forces exceeding the preset load, thus achieving flexible grinding. Because the surface of the additive part at the opening of the ball core 5 is uneven, the load is unstable. The buffer spring 26 and the spring 61 are used to buffer and balance the excessive vertical and horizontal load forces, which can significantly extend the service life of the sanding belt 25 and prevent damage to the grinding device.

[0025] This embodiment provides a flexible adaptive ball core orifice rounding grinding device, including a base plate 1. An electric turntable 3 is mounted on the base plate 1 via a support column 2. The electric turntable 3 is driven by a motor mounted on the upper end of the support column 2. A manual chuck 4 is mounted on the electric turntable 3. The ball core 5 is located on the electric turntable 3 and clamped by the manual chuck 4. A grinder 6 is installed at the orifice of the ball core 5. A mounting frame 7 is fixed to one side of the base plate 1. A longitudinal lead screw 9 driven by a longitudinal motor 8 and a longitudinal guide post 10 slidably connected to the mounting frame 7 are mounted on the mounting frame 7. The longitudinal guide post 10 is threadedly connected to the longitudinal lead screw 9. Starting the longitudinal motor 8 drives the longitudinal lead screw 9 to rotate, realizing the vertical lifting and lowering of the longitudinal guide post 10. A transverse lead screw 12 driven by a transverse motor 120 is installed at the crossbeam of the 0 via the mounting groove 11. A transverse guide post 13 is threaded onto the transverse lead screw 12. A rack 14 and a gear 15 that meshes with the rack 14 are installed through the transverse guide post 13. The gear 15 is driven by a drive motor 16 installed on the transverse guide post 13. A connecting sleeve 18 is slidably installed at the lower end of the rack 14 via a column rod 17. A lifting rod 19 is installed on the connecting sleeve 18. The lifting rod 19 is located in the slide groove 20 at the rear end of the grinder 6. Starting the transverse motor 120 can drive the transverse lead screw 12 to rotate, thereby realizing the left and right movement of the transverse guide post 13. After the longitudinal lead screw 9 and the transverse lead screw 12 are linked, the grinder 6 can move up and down and left and right and be positioned. One end of the rotating shaft 21 in the middle of the grinder 6 is located in the bearing hole 22 at the lower part of the transverse guide post 13. The front end of the grinder 6 is equipped with a grinding rod 23 through an elastic component. The front end of the grinding rod 23 is rotatably mounted with a roller 24 located at the hole of the ball core 5. A sanding belt 25 is provided between the roller 24 and the main roller of the grinder 6. Starting the drive motor 16 can drive the gear 15 to rotate, which in turn drives the lifting rod 19 to move up and down through the rack 14. When the lifting rod 19 moves up and down, it can slide smoothly along the slide groove 20 at the rear end of the grinder 6, thereby driving the grinder 6 to swing around the rotating shaft 21. After the electric turntable 3 rotates at the set speed, it works in conjunction with the grinder 6 to achieve uniform grinding and polishing of the rounded corner of the hole of the ball core 5. By changing the abrasive belt 25 with different grit, the automated and flexible grinding and polishing of the 5 holes of the ball core can be completed according to the process requirements. The adaptive structure of this device makes the grinding force more gentle, thereby obtaining a higher surface quality. It also supports one person to operate multiple machines in a standardized manner, effectively improving product quality and production efficiency, and reducing production costs.

[0026] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and incorporate common knowledge or customary techniques in the art disclosed herein. The specification and examples are to be considered exemplary only, and the true scope of this application is indicated by the claims.

[0027] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The embodiments of this application described above do not constitute a limitation on the scope of protection of this application.

Claims

1. A flexible adaptive ball core orifice rounding grinding device, characterized in that, include: A base plate (1) is provided with an electric turntable (3) via a support column (2). The electric turntable (3) is driven by a motor installed at the upper end of the support column (2). A manual chuck (4) is installed on the electric turntable (3). The ball core (5) is located on the electric turntable (3) and clamped by the manual chuck (4). A grinder (6) is provided at the opening of the ball core (5). A mounting bracket (7) is fixed to one side of the base plate (1). A longitudinal lead screw (9) driven by a longitudinal motor (8) and a longitudinal guide post (10) slidably connected to the mounting bracket (7) are mounted on the mounting bracket (7). The longitudinal guide post (10) is threadedly connected to the longitudinal lead screw (9). A transverse lead screw (12) driven by a transverse motor (120) is provided through a mounting groove (11) at the crossbeam of the longitudinal guide post (10). A transverse guide post (13) is threadedly connected to the transverse lead screw (12). A rack (14) and a gear (15) cooperating with the rack (14) are provided through the transverse guide post (13). The gear (15) is mounted on the transverse guide post (120). Driven by the drive motor (16) on 13), the lower end of the rack (14) is slidably mounted with a connecting sleeve (18) via a column rod (17). A lifting rod (19) is mounted on the connecting sleeve (18). The lifting rod (19) is located in the groove (20) at the rear end of the grinder (6). One end of the rotating shaft (21) in the middle of the grinder (6) is located in the bearing hole (22) at the lower part of the transverse guide column (13). A grinding rod (23) is mounted on the front end of the grinder (6) via an elastic component. A roller (24) located at the opening of the ball core (5) is rotatably mounted on the front end of the grinding rod (23). A sanding belt (25) is provided between the roller (24) and the main roller of the grinder (6).

2. The flexible adaptive ball core orifice rounding grinding device according to claim 1, characterized in that, The mounting bracket (7) includes a support plate (70), and a mounting plate (71) is fixed on the outside of the support plate (70). The mounting plate (71) is provided with a vertical mounting hole (72). The longitudinal screw (9) is rotatably installed in the vertical mounting hole (72). The longitudinal motor (8) is fixed on the lower side of the mounting plate (71) and its output shaft is fixedly connected to the lower end of the longitudinal screw (9). The longitudinal guide post (10) is provided with a through hole (100). The longitudinal guide post (10) is slidably connected to the mounting plate (71) through the through hole (100).

3. The flexible adaptive ball core orifice rounding grinding device according to claim 1, characterized in that, A limiting hole (130) is provided on one side of the transverse guide post (13), and the outer edge of the mounting groove (11) is located inside the limiting hole (130).

4. The flexible adaptive ball core orifice rounding grinding device according to claim 1, characterized in that, The lower end of the column rod (17) is fixed with a guide pin (170). Correspondingly, the connecting sleeve (18) is provided with a sliding groove (180) that extends through the bottom, and the two ends of the guide pin (170) are located in the sliding groove (180).

5. The flexible adaptive spherical core orifice rounding grinding device according to claim 4, characterized in that, A buffer spring (26) is also provided at the lower part of the column (17), and the lower part of the buffer spring (26) is located inside the connecting sleeve (18).

6. The flexible adaptive spherical core orifice rounding grinding device according to claim 1, characterized in that, The elastic component includes a limiting groove (60) disposed at the front end of the grinder (6), a spring (61) is installed in the limiting groove (60), and the other end of the spring (61) is connected to the grinding rod (23).

7. The flexible adaptive spherical core orifice rounding grinding device according to claim 6, characterized in that, A slot (600) is also provided on the inner side wall of the limiting slide groove (60). Correspondingly, a raised flat key (230) is also provided on the grinding rod (23), and the raised flat key (230) is located in the slot (600).

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