A method of dressing a tool
By designing a mechanized tool changing method with clamping components and quick-change connectors, the problems of low manual efficiency and space constraints in grinding large workpieces are solved, achieving efficient and precise tool changing for grinding, and adapting to the grinding needs of complex curved surfaces and curves.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHUZHOU GOFRONT EQUIP
- Filing Date
- 2025-10-24
- Publication Date
- 2026-07-31
AI Technical Summary
In the grinding process of large workpieces, manual grinding is inefficient and difficult to guarantee accuracy. Conventional pneumatic tool changing structures occupy too much space in a confined space and are difficult to adapt to the grinding needs of complex curved surfaces and curves.
Design a tool changing device including a clamping assembly, which realizes the mechanized replacement of grinding tools through a quick-change connector, uses a robotic arm and clamping assembly for axial insertion and removal operations, and combines radial locking components and inclined surface design to achieve stable clamping and replacement of tools.
It enables efficient and precise replacement of different types of grinding tools in confined spaces, meets the dynamic balance requirements of high-speed rotation, and improves grinding efficiency and accuracy.
Smart Images
Figure CN121315824B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of workpiece grinding machine processing equipment, specifically a method for changing grinding tools. Background Technology
[0002] In the manufacturing process of some large workpieces, various areas or components need to be machined. During machining processes such as turning, milling, and drilling, burrs will be generated in local areas of the workpiece due to machining. These burrs need to be removed by grinding. Generally, manual grinding with an angle grinder is used. Manual grinding is acceptable for small workpieces, but for large workpieces, manual grinding is extremely labor-intensive and inefficient. Moreover, when the workpiece requires high precision, it is difficult to guarantee the accuracy of manual grinding. When using automated equipment to grind large workpieces, because the workpiece grinding area has different curved surface features and varying sizes, different types of grinding tools are required to grind the workpiece.
[0003] Especially in relatively confined spaces, conventional pneumatic tool changing mechanisms require an air source and complex air circuits, resulting in excessive space usage and an overly large grinding unit that is unsuitable for grinding in confined areas. Therefore, a mechanized tool changing method or device needs to be designed. Summary of the Invention
[0004] To address the shortcomings of existing technologies, this invention provides a method for changing grinding tools and a tool changing device. The changing device includes a clamping assembly, a grinding unit connected to one end of a robotic arm, and a grinding tool connected to the grinding unit via a quick-change connector. The grinding tool can be axially inserted and removed within the quick-change connector. The invention specifically includes the following steps: The tool holder S41 drives the robotic arm to move the grinding tool to the holding assembly. The holding assembly is used to hold the outer circumferential surface of the grinding tool and can drive the grinding tool to separate the quick-change connector along the axial direction. At least one grinding tool for replacement is also held on the holding assembly. The grinding tool is held by the holding assembly. Tool disassembly S42 maintains the clamping force of the clamping assembly on the grinding tool and causes the grinding tool and quick-change connector to separate relative to each other along the axial direction, so that the grinding tool is disengaged from the quick-change connector; The tool is loaded via S43, which drives the robotic arm to move the quick-change connector to the grinding tool on the clamping assembly, allowing the grinding tool to be inserted axially into the quick-change connector to complete the tool change.
[0005] Furthermore, the quick-connect coupling includes an outer sleeve and an inner sleeve that are coaxially sleeved together. The outer sleeve and the inner sleeve can slide relative to each other axially. One end of the inner sleeve has a receiving space for inserting and removing grinding tools. The inner sidewall of the end of the receiving space has a through hole, in which a radial engaging member is embedded. There is a clearance space between the outer sidewall of the inner sleeve and the inner sidewall of the outer sleeve. When the outer sleeve slides axially upward relative to the inner sleeve, the clearance space can be opened so that the radial engaging member can be retracted radially into the clearance space. When the outer sleeve slides axially downward relative to the inner sleeve, it can abut against and push the radial engaging member to extend radially into the receiving space. One end of the grinding tool has a groove that cooperates with the radial engaging member. When the radial engaging member is embedded in the groove, the grinding tool is axially restricted within the receiving space. When the radial engaging member retracts into the clearance space, the restriction is released, and the grinding tool can be pulled out from the receiving space.
[0006] Furthermore, in the tool clamping step S41, the clamping assembly will simultaneously clamp the inner sleeve, the outer sleeve, and the grinding tool; In step S42 of tool disassembly, while maintaining the position of the inner sleeve, the outer sleeve is axially slid upward relative to the inner sleeve to open the clearance space. At this time, the grinding tool is pulled out axially downward. Under the pushing action of the groove at the end of the grinding tool, the radial locking member retracts into the clearance space, and the grinding tool is smoothly pulled out. In step S43, when the robotic arm is driven to the location of the grinding tool to be replaced on the clamping assembly, the clearance space is kept open. The grinding tool to be replaced is inserted into the receiving space axially upward using the clamping assembly. At this time, the outer sleeve is axially slid downward relative to the inner sleeve using the clamping assembly, and the radial engaging member is pushed radially into the receiving space and embedded in the groove of the grinding tool. At this time, the grinding tool is axially fixed and restricted in the receiving space, and the tool replacement is completed.
[0007] Furthermore, the clearance space is formed by a first annular inclined surface on the inner sidewall of the outer sleeve and a second annular inclined surface on the outer sidewall of the inner sleeve.
[0008] Furthermore, the radial engaging member is a ball embedded in a through hole, and the through hole is a tapered hole; the groove of the grinding tool is an arc-shaped groove that mates with the ball.
[0009] Furthermore, one end of the inner sleeve has an extended main shaft connection end, and the main shaft connection end and the inner wall of the outer sleeve are fitted together by a flat key.
[0010] Furthermore, a spring is installed at the end of the outer sleeve, and one end of the spring is connected to a retaining ring on the main shaft connection end. The outer sleeve and the outer wall of the inner sleeve are limited by a step.
[0011] Furthermore, the grinding tool and the receiving space are fitted with a tapered surface.
[0012] Furthermore, the clamping assembly includes a first clamping plate and a first driving unit for driving the first clamping plate to move upward, and also includes a third clamping plate and a second driving unit for driving the third clamping plate to move downward. The first clamping plate and the third clamping plate are fixed together by the second clamping plate. The first clamping plate has a first slot for clamping the outer sleeve, and the outer wall of the outer sleeve has a first annular groove. The second clamping plate has a second slot, the outer wall of the inner sleeve has a second annular groove, the third clamping plate has a third slot, and the outer wall of the grinding tool has a third annular groove.
[0013] Furthermore, in step S42 of tool disassembly, the driven robotic arm inserts the outer sleeve and inner sleeve into the first and second bayonets respectively through the first and second annular grooves. At the same time, the grinding tool is inserted into the third bayonet through the third annular groove. The first clamping plate is driven to pull the outer sleeve upward, and then the third clamping plate is driven downward to pull out the grinding tool. At this time, the other grinding tools that need to be replaced and are clamped in the third bayonets of the third clamping plate are also pulled downward to keep the position of the third clamping plate unchanged.
[0014] In step S43, the robotic arm is first driven to remove the outer sleeve and inner sleeve from the first and second clamping plates. Then, the robotic arm is driven to clamp the outer sleeve and inner sleeve into the other first and second clamping slots, respectively. At this time, the grinding tool to be replaced is in the corresponding axial position. The first clamping plate is driven to pull the outer sleeve upward, and the third clamping plate is driven to move the grinding tool to be replaced into the inner sleeve. Then, the first clamping plate is driven to reset the outer sleeve downward. The replacement grinding tool is firmly inserted into the inner sleeve, completing the tool replacement.
[0015] Compared with the prior art, the technical solution of this application has the following beneficial effects: The grinding tool replacement method proposed in this invention allows for the mechanical replacement of different tools. Quick-change couplings enable mechanical insertion and removal of the tools, and can maintain dynamic balance during high-speed rotation in grinding. Attached Figure Description
[0016] Figure 1 : Schematic diagram of tool changing method and device; Figure 2 Schematic diagram of the tool changing device; Figure 3 : Figure 2 Enlarged view at point C; Figure 4 Schematic diagram of the grinding unit structure; Figure 5 : Figure 3 Enlarged view at point D; Figure 6 Schematic diagram of quick-connect coupling structure; Figure 7 : Axial sectional view of quick-connect coupling; Figure 8 : Figure 7 A magnified view of a portion of the image; Figure 9 : Figure 7 Sectional view along direction E. Detailed Implementation
[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0018] A method for changing tools mechanically. Specifically, it is accomplished by a tool changing device (4), which includes a clamping assembly, see details below. Figures 1-5 .
[0019] The robotic arm (11) is connected to the grinding unit (12) and the grinding tool (42) is connected through a quick-change connector (41). The grinding tool (42) can be inserted and removed axially within the quick-change connector (41) and specifically includes the following steps.
[0020] Tool clamping S41, drive robotic arm (11) to move grinding tool (42) to clamping assembly, clamping assembly is used to clamp the outer circumferential surface of grinding tool (42), and can drive grinding tool (42) to separate quick-change connector (41) axially, clamping assembly also clamps at least one grinding tool (12) for replacement, using clamping assembly to clamp grinding tool (42); Tool disassembly S42 maintains the clamping force of the clamping assembly on the grinding tool (42) and causes the grinding tool (42) and quick-change connector (41) to separate relative to each other along the axial direction, so that the grinding tool (42) is disengaged from the quick-change connector (41); Tool loading S43 drives the robotic arm (11) to move the quick-change connector (41) to the grinding tool (12) on the clamping assembly for replacement, so that the grinding tool (12) is inserted into the quick-change connector (41) axially to complete the tool replacement.
[0021] In a more preferred embodiment, see details below. Figures 6-9The quick-connector (41) includes an outer sleeve (43) and an inner sleeve (44) that are coaxially connected. The outer sleeve (43) and the inner sleeve (44) can slide relative to each other axially. One end of the inner sleeve (44) is provided with a receiving space (45) for inserting and removing the grinding tool (12). A through hole (451) is provided on the inner side wall of the end of the receiving space (45). A radial engaging member is embedded in the through hole (451). There is a clearance space (46) between the outer side wall of the inner sleeve (44) and the inner side wall of the outer sleeve (43). When the outer sleeve (43) slides upward relative to the inner sleeve (44) axially, the clearance space (46) can be opened so that the radial engaging member can be retracted into the clearance space (46) radially. When the outer sleeve (43) slides downward relative to the inner sleeve (44) axially, it can abut and push the radial engaging member to extend into the receiving space (45) radially.
[0022] Correspondingly, a groove (121) is provided at one end of the grinding tool (12) to cooperate with the radial engaging member. When the radial engaging member is inserted into the groove (121), the grinding tool (12) is axially restricted within the receiving space (45). When the radial engaging member retracts into the clearance space (46), the restriction is released, and the grinding tool (12) can be pulled out from the receiving space (45). It should be noted that when the radial engaging member is inserted into the groove (121), it is abutted against the inner sidewall of the outer sleeve (43). At this time, the radial engaging member maintains a stable restrictive force on the end of the grinding tool (12) through the groove (121). Under this stable restrictive force, the grinding tool (12) can be prevented from rotating relative to the inner sleeve (44).
[0023] In a more preferred embodiment, the side wall of the grinding tool (12) and the inner sleeve (44) can be connected by a key to increase the rotational limiting force of the grinding tool (12) relative to the inner sleeve (44), but the control accuracy and angle of the grinding tool (12) axially inserting into the receiving space (45) of the inner sleeve (44) are limited.
[0024] In step S41, the clamping assembly will simultaneously clamp the inner sleeve (44), the outer sleeve (43), and the grinding tool (12).
[0025] In step S42, while maintaining the position of the inner sleeve (44), the outer sleeve (43) is axially slid upward relative to the inner sleeve (44) to open the clearance space (46). At this time, the grinding tool (12) is pulled out axially downward. Under the pushing action of the end slot (121) of the grinding tool (12), the radial locking member retracts into the clearance space (46), and the grinding tool (12) is successfully pulled out.
[0026] In step S43, when the robotic arm (11) is driven to the grinding tool (12) for replacement on the clamping assembly, the clearance space (46) is kept open. The grinding tool (12) for replacement is inserted into the receiving space (45) axially upward using the clamping assembly. At this time, the outer sleeve (43) is axially slid downward relative to the inner sleeve (44) using the clamping assembly, and the radial engaging member is pushed radially into the receiving space (45) and embedded in the slot (121) of the grinding tool (12). At this time, the grinding tool (12) is axially fixed and restricted in the receiving space (45) to complete the tool replacement.
[0027] In a more preferred embodiment, the clearance space (46) is formed by a first annular inclined surface (431) on the inner sidewall of the outer sleeve (43) and a second annular inclined surface (441) on the outer sidewall of the inner sleeve (44). When the outer sleeve (43) slides axially downward relative to the inner sleeve (44), the first annular inclined surface (431) can push the radial engaging member into the receiving space (45). Conversely, the first annular inclined surface (431) and the second annular inclined surface (441) separate axially relative to each other, thereby opening the clearance space (46) and allowing the radial engaging member to retract into the clearance space (46).
[0028] In a more preferred embodiment, the radial engaging member is a ball (452) embedded in a through hole (451), the through hole (451) being a tapered hole. The taper of the tapered hole is very small, allowing the ball (452) to extend into the receiving space (45) without falling out.
[0029] In a more preferred embodiment, the groove (121) of the grinding tool (12) is an arc-shaped groove that mates with the ball (452). This increases the contact force between the ball (452) and one end of the grinding tool (12) when the ball (452) is embedded in the arc-shaped groove, making the insertion of the grinding tool (12) more stable.
[0030] In a more preferred embodiment, one end of the inner sleeve (44) has an extended spindle connection end (442), and the spindle connection end (442) and the inner wall of the outer sleeve (43) are engaged by a flat key (443). This prevents relative rotation between the inner sleeve (44) and the outer sleeve (43).
[0031] In a more preferred embodiment, a spring (432) is installed at the end of the outer sleeve (43), one end of the spring (432) is connected to a retaining ring (443) on the main shaft connection end (442), and the outer sleeve (43) and the outer side wall of the inner sleeve (44) are limited by a step. When the outer sleeve (43) is pulled axially upward by the clamping assembly, after the clamping assembly is released, the outer sleeve (43) will return to its original position under the reset action of the spring (432) and be limited by the step, so that the inner side wall of the inner sleeve (44) can maintain the resistance force acting on the ball (452).
[0032] In a more preferred embodiment, one end of the grinding tool (12) and the receiving space (45) are fitted with a conical surface. Since the grinding tool (12) needs to rotate at high speed, the conical surface fit is beneficial for dynamic balance under high speed rotation, and the conical surface fit also has a limiting effect on the insertion of the grinding tool (12) into the receiving space (45).
[0033] In a more preferred embodiment, see details below. Figure 5 and Figure 6 The tool changing device (4) includes a clamping assembly and a working platform for carrying the clamping assembly. The clamping assembly includes a first clamping plate (47) and a first driving unit for driving the first clamping plate (47) to move upward. It also includes a third clamping plate (49) and a second driving unit for driving the third clamping plate (49) to move downward. A second clamping plate (48) is fixed between the first clamping plate (47) and the third clamping plate (49). A first slot (471) for clamping the outer sleeve (43) is opened on the first clamping plate (47). A first annular groove (433) is opened on the outer wall of the outer sleeve (43). A second slot (481) is opened on the second clamping plate (48). A second annular groove (445) is opened on the outer wall of the inner sleeve (44). A third slot (491) is opened on the third clamping plate (49). A third annular groove (122) is opened on the outer wall of the grinding tool (12).
[0034] When disassembling the tool, the drive arm (11) inserts the outer sleeve (43) and inner sleeve (44) into the first bayonet (471) and the second bayonet (481) respectively through the first annular groove (433) and the second annular groove (445). At the same time, the grinding tool (12) is inserted into the third bayonet (491) through the third annular groove (122). The drive plate (47) pulls the outer sleeve (43) upward, and then drives the third plate (49) downward to pull out the grinding tool (12). At this time, the grinding tools (12) that need to be replaced and are locked in the other third bayonet (491) of the third plate (49) are also pulled downward to keep the position of the third plate (49) unchanged.
[0035] When loading the tool, first drive the robotic arm (11) to make the outer sleeve (43) and inner sleeve (44) exit the first clamping plate (47) and the second clamping plate (48), then drive the robotic arm (11) to clamp the outer sleeve (43) and inner sleeve (44) into the other first clamping slot (471) and second clamping slot (481) respectively. At this time, the grinding tool (12) to be replaced is in the corresponding axial position. Drive the first clamping plate (47) to pull the outer sleeve (43) upward, and drive the third clamping plate (49) to drive the grinding tool (12) to be replaced upward to insert into the inner sleeve (44). Then drive the first clamping plate (47) to reset the outer sleeve (43) downward. The replacement grinding tool (12) is firmly inserted into the inner sleeve (44) to complete the tool replacement.
[0036] The first drive unit and the second drive unit can use cylinders to drive the first clamping plate (47) and the third clamping plate (49). The second clamping plate (48) is fixedly connected to the working platform through the connecting columns at both ends.
[0037] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0038] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A method for changing grinding tools, characterized in that, A tool changing device is provided, comprising a changing device (4) including a clamping assembly, a grinding unit (12) connected to one end of a robotic arm (11), a grinding tool (42) connected to the grinding unit (12) via a quick-change connector (41), the grinding tool (42) being axially inserted and removed within the quick-change connector (41), and specifically including the following steps: Tool clamping S41, drive robotic arm (11) to move grinding tool (42) to clamping assembly, clamping assembly is used to clamp the outer circumferential surface of grinding tool (42), and can drive grinding tool (42) to separate quick-change connector (41) axially, clamping assembly also clamps at least one grinding tool (42) for replacement, using clamping assembly to clamp grinding tool (42); Tool disassembly S42 maintains the clamping force of the clamping assembly on the grinding tool (42) and causes the grinding tool (42) and quick-change connector (41) to separate relative to each other along the axial direction, so that the grinding tool (42) is disengaged from the quick-change connector (41); Tool loading S43 drives the robotic arm (11) to move the quick-change connector (41) to the grinding tool (42) on the clamping assembly for replacement, so that the grinding tool (42) is inserted into the quick-change connector (41) axially to complete the tool replacement; The quick-connector (41) includes an outer sleeve (43) and an inner sleeve (44) that are coaxially sleeved together. The outer sleeve (43) and the inner sleeve (44) can slide relative to each other axially. One end of the inner sleeve (44) is provided with a receiving space (45) for inserting and removing a grinding tool (42). A through hole (451) is provided on the inner sidewall of the end of the receiving space (45). A radial locking member is embedded in the through hole (451). There is a clearance space (46) between the outer sidewall of the inner sleeve (44) and the inner sidewall of the outer sleeve (43). When the outer sleeve (43) slides axially upward relative to the inner sleeve (44), the clearance space can be opened. 46) The radial engaging member can be retracted radially into the clearance space (46). When the outer sleeve (43) slides axially downward relative to the inner sleeve (44), it can abut and push the radial engaging member to extend radially into the receiving space (45). One end of the grinding tool (42) is provided with a groove (121) that cooperates with the radial engaging member. When the radial engaging member is embedded in the groove (121), the grinding tool (42) is axially restricted in the receiving space (45). When the radial engaging member retracts into the clearance space (46), the restriction is released, and the grinding tool (42) can be pulled out from the receiving space (45).
2. The grinding tool replacement method as described in claim 1, characterized in that, In step S41, the clamping assembly will simultaneously clamp the inner sleeve (44), the outer sleeve (43), and the grinding tool (42). In step S42, while keeping the inner sleeve (44) in position, the outer sleeve (43) slides upward axially relative to the inner sleeve (44) to open the clearance space (46). At this time, the grinding tool (42) is pulled out axially downward. Under the pushing action of the end slot (121) of the grinding tool (42), the radial locking member retracts into the clearance space (46), and the grinding tool (42) is successfully pulled out. In step S43, when the robotic arm (11) is driven to the grinding tool (42) for replacement on the clamping assembly, the clearance space (46) is kept open. The grinding tool (42) for replacement is inserted into the receiving space (45) axially upward using the clamping assembly. At this time, the outer sleeve (43) is axially slid downward relative to the inner sleeve (44) using the clamping assembly, and the radial engaging member is pushed radially into the receiving space (45) and embedded in the slot (121) of the grinding tool (42). At this time, the grinding tool (42) is axially fixed and restricted in the receiving space (45) to complete the tool replacement.
3. The grinding tool replacement method as described in claim 1, characterized in that, The clearance space (46) is formed by the first annular inclined surface (431) of the inner sidewall of the outer sleeve (43) and the second annular inclined surface (441) of the outer sidewall of the inner sleeve (44).
4. The grinding tool replacement method as described in claim 3, characterized in that, The radial engaging member is a ball (452) embedded in a through hole (451), and the through hole (451) is a tapered hole; the groove (121) of the grinding tool (42) is an arc-shaped groove that cooperates with the ball (452).
5. The grinding tool replacement method as described in claim 4, characterized in that, The inner sleeve (44) has an extended spindle connection end (442) at one end, and the spindle connection end (442) and the inner wall of the outer sleeve (43) are connected by a flat key.
6. The grinding tool replacement method as described in claim 5, characterized in that, A spring (432) is installed at the end of the outer sleeve (43). One end of the spring (432) is connected to a retaining ring (443) on the main shaft connection end (442). The outer sleeve (43) and the outer side wall of the inner sleeve (44) are limited by a step.
7. The grinding tool replacement method as described in claim 6, characterized in that, The grinding tool (42) and the receiving space (45) are connected by a conical surface.
8. The grinding tool replacement method as described in claim 7, characterized in that, The clamping assembly includes a first clamping plate (47) and a first driving unit for driving the first clamping plate (47) to move upward, and also includes a third clamping plate (49) and a second driving unit for driving the third clamping plate (49) to move downward. The first clamping plate (47) and the third clamping plate (49) are fixed to a second clamping plate (48). The first clamping plate (47) has a first slot (471) for clamping the outer sleeve (43), the outer wall of the outer sleeve (43) has a first annular groove (433), the second clamping plate (48) has a second slot (481), the outer wall of the inner sleeve (44) has a second annular groove (445), the third clamping plate (49) has a third slot (491), and the outer wall of the grinding tool (42) has a third annular groove (122).
9. The grinding tool replacement method as described in claim 8, characterized in that, In step S42, the mechanical arm (11) drives the outer sleeve (43) and inner sleeve (44) to be inserted into the first bayonet (471) and the second bayonet (481) respectively through the first annular groove (433) and the second annular groove (445). At the same time, the grinding tool (42) is inserted into the third bayonet (491) through the third annular groove (122). The first clamping plate (47) is driven to pull the outer sleeve (43) upward, and then the third clamping plate (49) is driven downward to pull out the grinding tool (42). At this time, the grinding tools (42) that need to be replaced and are clamped in the other third bayonet (491) of the third clamping plate (49) are also pulled downward to keep the position of the third clamping plate (49) unchanged. In step S43, the robotic arm (11) is first driven to remove the outer sleeve (43) and inner sleeve (44) from the first clamping plate (47) and the second clamping plate (48). Then, the robotic arm (11) is driven to insert the outer sleeve (43) and inner sleeve (44) into the other first clamping slot (471) and second clamping slot (481) respectively. At this time, the grinding tool (42) to be replaced is in the corresponding axial position. The first clamping plate (47) is driven to pull the outer sleeve (43) upward, and the third clamping plate (49) is driven to drive the grinding tool (42) to be replaced upward to insert into the inner sleeve (44). Then, the first clamping plate (47) is driven to reset the outer sleeve (43) downward. The replaced grinding tool (42) is firmly inserted into the inner sleeve (44) to complete the tool replacement.