A polishing device for ductile iron manhole covers

Abstract

The utility model discloses a kind of grinding devices for nodular cast iron well lid, it is related to the field of grinding device.It includes horizontal square tube and vertical square tube, vertical square tube is vertically slidably installed with supporting leg by means of linear drive assembly, and is fixedly installed with auxiliary wheel;Horizontal square tube front end bottom is fixedly installed with support wheel, shell extends downward and protrudes the bottom surface of horizontal square tube, transmission assembly is integrated in shell, driving shaft passes through shell and extends to below horizontal square tube, and detachably installed with thousand leaf wheel or steel wire wheel;Horizontal square tube bottom end is fixedly installed with the protective cover of bottom opening, and dust suction box is fixedly installed on the both sides of protective cover, and suction box is connected with suction connector.The beneficial effects of the utility model are: the stable main body formed by horizontal square tube and vertical square tube, combined with handle, support wheel and auxiliary wheel to ensure flexible operation movement, then protect by protective cover and collect scrap by dust suction box, so that the device is convenient to operate, polishing is adapted, operation is safe and effective dust control.

Description

Technical Field

[0001] This utility model belongs to the field of grinding devices, specifically the field of ductile iron manhole cover production equipment, and relates to a grinding device for ductile iron manhole covers. Background Technology

[0002] Ductile iron manhole covers, as core components of infrastructure construction, are widely used in roads, residential areas, and various municipal engineering projects. Their quality and performance directly affect the safety of passage and the stability of facilities in public areas. To meet the protective performance requirements of manhole covers while also considering their aesthetic appearance, the surface of ductile iron manhole covers is usually designed with various embossed patterns or custom designs. These complex structures place higher demands on the grinding and processing of manhole covers. Furthermore, due to the characteristics of the casting process, defects such as casting marks, edge flash, surface burrs, and oxide scale inevitably remain on the surface during the manhole cover casting production process. These defects must undergo rigorous grinding and polishing to meet the appearance quality and performance standards of the finished product.

[0003] Currently, the grinding and deburring of ductile iron manhole covers in the industry still mainly relies on manual operation using handheld angle grinders. Operators must hold the angle grinder and manually control the grinding angle and pressure to treat the surface of the manhole cover point by point. While this method has the advantages of low tool cost and high operational flexibility, it has several insurmountable drawbacks: First, the operation process depends entirely on the operator's experience and physical exertion, which easily leads to worker fatigue over long periods. This not only results in extremely high labor intensity but also significantly restricts overall production efficiency due to the long grinding time per manhole cover. Second, manual operation lacks stability, and the grinding quality is significantly affected by the worker's skill level and sense of responsibility. It is difficult to guarantee the uniformity and consistency of the treatment of the manhole cover surface, especially complex areas such as recessed areas and edges of the patterned surfaces, easily leading to quality problems such as missed grinding and over-grinding. Third, the high-speed rotating grinding tool lacks effective protection, and the high-temperature sparks generated during operation can easily cause fire hazards. Furthermore, a large amount of suspended metal dust is directly inhaled by workers, seriously endangering their respiratory health and posing significant safety and occupational health risks. To address the shortcomings of manual grinding, some manufacturers have attempted to replace manual grinding with traditional push-type belt sanders, which are originally designed for grinding flat surfaces such as floors and slabs. However, their application to grinding ductile iron manhole covers presents significant compatibility issues: Firstly, the sanding belt makes linear contact with the manhole cover surface, only able to grind the raised parts of the pattern, failing to effectively reach recessed areas and gaps in the pattern, resulting in incomplete grinding and failing to meet the overall surface treatment requirements of the manhole cover. Secondly, the pressure plate of the belt sander is mostly a rigid structure, which easily causes mechanical interference when in contact with the uneven pattern on the manhole cover surface. This not only leads to high pushing resistance and slow movement of the equipment but also causes uneven stress on the sanding belt, resulting in abnormal wear, deviation, or even tearing of the sanding belt, increasing equipment maintenance costs and the risk of work interruption. In addition, the design of traditional push-type belt sanders does not fully consider the dust collection needs of metal grinding scenarios, lacking a targeted dust extraction structure. Metal dust generated during operation still permeates the working environment, making the working environment still harsh. Utility Model Content

[0004] This invention addresses the technical problems of low efficiency, poor stability, and harmful dust generation during manhole cover grinding, providing a grinding device for ductile iron manhole covers. The sturdy main body, composed of horizontal and vertical square tubes, combined with a handle, support wheels, and auxiliary wheels, ensures flexible operation and movement. A protective cover and a dust collection box further enhance the device's protection, making it easy to operate, suitable for various grinding applications, safe to work with, and effectively controlling dust.

[0005] The technical solution adopted by this utility model is as follows: A grinding device for ductile iron manhole covers is provided, comprising a horizontal square tube and a vertical square tube. The vertical square tube is disposed at the rear end of the horizontal square tube and fixedly connected to it. A handle is fixedly installed at the top of the rear end of the vertical square tube. A support leg is vertically slidably installed inside the vertical square tube via a linear drive assembly, and the support leg extends out of the bottom end of the vertical square tube and is fixedly installed with an auxiliary wheel. A support wheel is fixedly installed at the bottom of the front end of the horizontal square tube. A power structure is fixedly installed on one side of the horizontal square tube, and a housing is fixedly installed on the other side. The bottom surface of the horizontal square tube extends downward and protrudes. A transmission component is integrated inside the outer shell. The output shaft of the power structure passes through the outer shell and is driven and installed with the transmission component. A drive shaft is driven and installed on the transmission component. The drive shaft passes through the outer shell and extends to the bottom of the horizontal square tube. A flap wheel or wire wheel is detachably installed. A protective cover with a bottom opening is fixedly installed at the bottom end of the horizontal square tube. The protective cover covers the flap wheel or wire wheel and the flap wheel or wire wheel protrudes from the protective cover. A dust collection box is fixedly installed on both sides of the protective cover. An air extraction connector is connected to the dust collection box.

[0006] The main frame of the device is formed by the fixed connection of horizontal and vertical square tubes, resulting in a simple and stable structure. The handles on the vertical square tubes facilitate operation and increase maneuverability. Support wheels and auxiliary wheels work together to enable flexible movement of the device, reducing the difficulty of relocation and facilitating the grinding of manhole covers. The linkage design of the power structure, transmission components, and drive shaft on the horizontal square tubes can stably drive the flap wheel or wire wheel to meet the grinding operation requirements. The detachable design of the flap wheel and wire wheel allows for flexible switching according to the grinding precision, adapting to different grinding scenarios. At the same time, the protective cover can effectively block flying debris and sparks during grinding, ensuring the safety of operators. The dust collection boxes and air extraction connectors on both sides of the protective cover can collect grinding debris in a timely manner, reducing dust pollution and ensuring both a clean operating environment and personnel health.

[0007] To further optimize this technical solution, the linear drive assembly includes a through hole coaxially opened on the support leg, a screw nut fixedly installed in the through hole, and a screw rod connected to the screw nut; an end cap is fixedly installed at the top of the vertical square tube, the top of the screw rod coaxially passes through the end cap and is rotatably installed with the end cap, and a handwheel is fixedly installed at the top of the screw rod.

[0008] The meshing transmission structure of the lead screw and lead nut ensures high transmission accuracy. The lifting height of the support foot can be precisely adjusted by turning the handwheel, thereby controlling the position of the auxiliary wheel and grinding components. The operation is simple and labor-saving.

[0009] To further optimize this technical solution, mounting panels are provided on both sides of the horizontal square tube. The mounting panels are fixed to the horizontal square tube by bolts, and the power structure and the outer shell are fixedly installed to the mounting panels respectively.

[0010] The mounting panel is fixed to both sides of the horizontal square tube with bolts, which not only increases the installation contact area between the power structure and the shell, improving the firmness and stability of the installation, and preventing the components from loosening due to vibration during operation, but also facilitates the disassembly and replacement of the mounting panel by bolts, providing convenience for the maintenance and repair of the power structure and the shell.

[0011] To further optimize this technical solution, the power structure includes a servo motor, which is fastened to one of the mounting panels by bolts, and the output shaft of the servo motor passes through the horizontal square tube and the mounting panel, and enters the housing.

[0012] As a power structure, the servo motor has controllable speed and stable output power. It can precisely adjust the rotation speed of the flap wheel or wire wheel according to the grinding requirements, adapting to the grinding of manhole covers with different materials and surface conditions, improving the grinding quality. The servo motor is fastened to the mounting panel with bolts, making it securely installed and easy to disassemble, facilitating motor maintenance and replacement. The through-type installation design of the output shaft ensures the directness and stability of power transmission.

[0013] To further optimize this technical solution, both the outer shell and the mounting panel are made of stainless steel. The outer shell and the mounting panel are welded and fixed, and the outer shell is fastened to the protective cover by bolts.

[0014] The welding and fixing of the outer shell and the mounting panel improves the stability of the installation and prevents the two from separating due to vibration during operation. The outer shell and the protective cover are fastened together by bolts, which improves the stability of the protective cover installation and facilitates the disassembly and maintenance of the protective cover.

[0015] To further optimize this technical solution, the outer shell includes a stainless steel shell that is fixedly connected to the mounting panel and the protective cover, the transmission components are integrated inside the shell, and a cover is detachably installed on the outside of the shell by bolts.

[0016] The stainless steel housing provides a closed installation space for the transmission components, effectively isolating them from external dust and debris, ensuring stable operation. The removable cover design on the outside of the housing allows operators to easily open the housing to inspect, lubricate, and repair the internal transmission components, reducing maintenance difficulty and minimizing equipment downtime.

[0017] To further optimize this technical solution, the transmission component includes a matching transmission belt and pulleys, with the pulleys respectively located on the output shaft and drive shaft within the housing.

[0018] The transmission assembly adopts a transmission belt and pulley combination structure, which provides smooth transmission and low noise. It can effectively buffer the impact during power transmission, protect the power structure and drive shaft. The pulleys are installed on the output shaft and drive shaft respectively. The structure is simple and low cost, and the belt is easy to replace. When the transmission components are worn, maintenance and replacement are convenient, reducing the cost of use.

[0019] To further optimize this technical solution, a clamping nut is threadedly connected to the free end of the drive shaft. The clamping nut abuts against the end face of the flap wheel or wire wheel, and a notch matching the clamping nut is provided on the front of the protective cover.

[0020] The drive shaft is fixed to the flap wheel or wire wheel by a clamping nut. The fixing method is simple and reliable, which can effectively prevent the grinding wheel from slipping during the grinding process and ensure the stability of the grinding operation. The notch design on the front of the protective cover provides ample operating space for tightening and loosening the clamping nut, which facilitates quick replacement of the flap wheel or wire wheel and improves work efficiency.

[0021] To further optimize this technical solution, at least one filter assembly is detachably connected inside the dust collection box. The filter assembly includes an outer frame that is interference-fitted with the inner wall of the dust collection box, and a metal filter screen is disposed inside the outer frame.

[0022] The filter components inside the dustbin can intercept the sucked-in debris. The metal filter can effectively block large sparks and debris, preventing them from entering the external vacuum cleaner and causing blockage or damage, thus protecting the vacuum cleaner and extending its service life. The metal filter is press-fitted into the dustbin through the outer frame, making it securely installed and easy to disassemble. This facilitates regular cleaning or replacement of the filter, ensuring the stability of the filtration effect.

[0023] To further optimize this technical solution, a wear-resistant bushing is fitted inside the vertical square tube, and the wear-resistant bushing is slidably connected to the support leg.

[0024] The wear-resistant bushing installed inside the vertical square tube can effectively reduce the direct friction between the support leg and the inner wall of the vertical square tube, reduce the wear of both, extend the service life of the support leg and the vertical square tube, and ensure the smooth vertical sliding of the support leg, avoid adjustment jamming due to excessive frictional resistance, and improve the flexibility and reliability of the device adjustment.

[0025] The beneficial effects of this utility model are as follows: 1. The linear drive assembly of lead screw and nut in conjunction with handwheel can precisely adjust the height of the grinding component. When moving the device, it can avoid wear and tear between the grinding component and the ground, and adapt to the grinding needs of manhole covers with different thicknesses or surface flatness, thus improving the flexibility of use. 2. The horizontal and vertical square tubes form a stable frame with a simple structure and reliable use. The mounting panel enhances the connection between the power structure and the outer shell, and the flap wheel or wire wheel can be quickly disassembled and assembled by tightening the nut. Combined with the notch design of the protective cover, it is easy to switch molds according to needs, improving the versatility and practicality of use. 3. The protective cover effectively blocks grinding debris and sparks from flying, preventing accidental injury to operators. In addition, the dust collection box on the protective cover, together with the metal filter assembly, can collect debris to reduce pollution and protect the external dust collection equipment, ensuring the safety of the working environment in all aspects. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the grinding device in this embodiment; Figure 2 This is a schematic diagram of the assembly structure of the horizontal square tube and the vertical square tube in this embodiment; Figure 3 This is a schematic diagram showing the disassembled structure of the vertical square tube, support legs, and lead screw in this embodiment; Figure 4 This is a schematic diagram of the assembly structure of the horizontal square tube, support wheel, protective cover, and outer shell in this embodiment; Figure 5 This is a schematic diagram of the disassembled structure of the outer shell in this embodiment; Figure 6 This is a schematic diagram of the protective cover in this embodiment; Figure 7 This is a schematic diagram showing the disassembled structure of the dust collection box and the metal filter in this embodiment.

[0027] In the diagram, 1. Horizontal square tube; 101. Mounting panel; 102. Servo motor; 2. Vertical square tube; 201. Handle; 202. End cap; 203. Lead screw; 2031. Handwheel; 204. Wear-resistant bushing; 3. Support leg; 301. Through hole; 302. Nut; 4. Auxiliary wheel; 5. Support wheel; 6. Outer shell; 601. Housing; 6011. Drive belt; 6012. Pulley; 602. Cover; 7. Drive shaft; 701. Compression nut; 8. Flap wheel; 9. Wire wheel; 10. Protective cover; 1001. Notch; 11. Dust collection box; 1101. Air extraction connector; 1102. Outer frame; 1103. Metal filter. Detailed Implementation

[0028] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0029] Please see the appendix Figure 1 Appendix Figure 2 A grinding device for ductile iron manhole covers includes a horizontal square tube 1 and a vertical square tube 2. The vertical square tube 2 is located at the rear end of the horizontal square tube 1 and is fixedly connected to the horizontal square tube 1. Both the horizontal square tube 1 and the vertical square tube 2 can be made of stainless steel and are fixed by welding. A support wheel 5 is fixedly installed at the front of the bottom end of the horizontal square tube 1. A support leg 3 is vertically slidably installed inside the vertical square tube 2 by means of a linear drive assembly. The support leg 3 extends out of the bottom end of the vertical square tube 2 and is fixedly installed with an auxiliary wheel 4, thereby supporting the horizontal square tube 1 and the vertical square tube 2. Please see the appendix Figure 2 Appendix Figure 3 The linear drive assembly for driving the vertical square tube 2 to move vertically can be a matching lead screw 203 and lead screw nut 302. The lead screw nut 302 is installed on the support leg 3. A through hole 301 is opened coaxially on the support leg 3, and the lead screw nut 302 is installed in the through hole 301. The lead screw 203, which is matched with the lead screw nut 302, extends upward through the vertical square tube 2. An end cap 202 is fixedly connected to the top of the vertical square tube 2. The lead screw 203 is rotatably connected to the end cap 202, and a handwheel 2031 is fixedly installed at the top of the lead screw 203 to make the rotation of the lead screw 203 smoother and easier. The lead screw 203 engages with the lead screw nut 302 to push the support leg 3 to slide vertically along the vertical square tube 2. A wear-resistant bushing 204 is fitted inside the vertical square tube 2. The support leg 3 is slidably connected to the wear-resistant bushing 204. By applying lubricating oil to the support leg 3 and the wear-resistant bushing 204, the smoothness of the vertical sliding of the support leg 3 and the reduction of frictional resistance are ensured. Please see the appendix Figure 1 Appendix Figure 4A power structure is fixedly installed on one side of the horizontal square tube 1, and a housing 6 is fixedly installed on the other side. The power structure and the housing 6 are installed on the horizontal square tube 1 through a mounting panel 101. The mounting panel 101 is located on both sides of the horizontal square tube 1 and is fixed to the horizontal square tube 1 by bolts. The mounting panel 101 increases the installation area of ​​the power structure and the housing 6 to ensure installation reliability. The power structure is a servo motor 102. The servo motor 102 is fastened to one of the mounting panels 101 by bolts. The housing 6 is fixed to the other mounting panel 101. Both the housing 6 and the mounting panel 101 can be made of stainless steel. The housing 6 is welded to the mounting panel 101. The housing 6 extends downward and protrudes from the bottom surface of the horizontal square tube 1. A drive shaft 7 is rotatably installed at the bottom of the housing 6. The drive shaft 7 extends to the bottom of the horizontal square tube 1, and a flap wheel 8 or a wire wheel 9 is coaxially installed on the drive shaft 7. Please see the appendix Figure 5 The output shaft of the servo motor 102 passes through the horizontal square tube 1 and the mounting panel 101 and enters the housing 6. The output shaft is driven by the drive shaft 7 through the transmission component. The transmission component is integrated in the housing 601 of the housing 6. The stainless steel housing 601 of the housing 6 is welded and fixed to the mounting panel 101. A cover 602 is detachably installed on the housing 601. The transmission component in the housing 601 can be a matching transmission belt 6011 and pulley 6012. The pulley 6012 is coaxially mounted with the output shaft and drive shaft 7 in the housing 601 respectively. The transmission structure is simple and stable and reliable in use. Please see the appendix Figure 1 Appendix Figure 4 Appendix Figure 6 The free end of the drive shaft 7 is threaded with a clamping nut 701. After the clamping nut 701 abuts against the end face of the flap wheel 8 or the wire wheel 9, the flap wheel 8 or the wire wheel 9 is fixed on the drive shaft 7. The flap wheel 8 or the wire wheel 9 is covered with a protective cover 10. The protective cover 10 is fixedly connected to the bottom surface of the horizontal square tube 1, and the flap wheel 8 or the wire wheel 9 protrudes from the bottom opening of the protective cover 10. The housing 601 is fastened to the outside of the protective cover 10 by bolts. The other side of the protective cover 10 is provided with a notch 1001 that matches the clamping nut 701, so that the clamping nut 701 abuts against the flap wheel 8 or the wire wheel 9, thereby enhancing the firmness of the assembly between the flap wheel 8 or the wire wheel 9 and the drive shaft 7. The protective cover 10 ensures safety during the grinding process. Please see the appendix Figure 6 Appendix Figure 7Dust collection boxes 11 are fixedly installed on both sides of the protective cover 10. The dust collection box 11 is connected to an air extraction connector 1101, which is connected to an external air source. If connected to a vacuum cleaner, the dust debris can be sucked up during the grinding process. At least one filter assembly is detachably connected inside the dust collection box 11. The filter assembly includes an outer frame 1102 that is interference-fitted to the inner wall of the dust collection box 11. A metal filter screen 1103 is provided inside the outer frame 1102. The metal filter screen 1103 intercepts large sparks and debris, ensuring the safety of the external vacuuming equipment.

[0030] The working principle of this grinding device for ductile iron manhole covers is as follows: Before use, rotate the handwheel 2031 at the top of the lead screw 203 to engage the lead screw 203 with the nut 302 in the through hole 301 of the support leg 3. This allows the support leg 3 to slide vertically along the vertical square tube 2, thereby driving the auxiliary wheel 4 to rise and fall. By adjusting the height of the auxiliary wheel 4, the flap wheel 8 or wire wheel 9 below the horizontal square tube 1 can maintain an appropriate gap with the ground, facilitating the overall pushing and moving of the device. This makes operation labor-saving and flexible, and avoids damage to the flap wheel 8 or wire wheel 9. During grinding operations, the height of the auxiliary wheel 4 is adjusted again by rotating the handwheel 2031 to raise and lower the flap wheel 8 or wire wheel 9, thus adapting to the grinding needs of manhole covers with different thicknesses or surface flatness. The engagement structure of the lead screw 203 and the lead nut 302 has a self-locking function, which can effectively ensure the stability of the device support. At the same time, the wear-resistant bushing 204 inside the vertical square tube 2, in conjunction with the applied lubricating oil, can ensure the smoothness of the adjustment process of the support leg 3 and reduce mechanical wear. After the position adjustment of the flap wheel 8 or the wire wheel 9 is completed, the servo motor 102 is started. The output shaft of the servo motor 102 transmits power to the transmission belt 6011 inside the housing 6, and the rotational power of the servo motor 102 is smoothly transmitted to the drive shaft 7 through the transmission belt 6011. The flap wheel 8 or the wire wheel 9 is fixed to the drive shaft 7 by the clamping nut 701, thereby driving the flap wheel 8 or the wire wheel 9 to rotate synchronously. The notch 1001 on the protective cover 10 provides operating space for the installation and removal of the clamping nut 701, making it convenient to replace the flap wheel 8 or the wire wheel 9 according to the grinding requirements. During the grinding process, the operator moves the device by holding the handle 201 on the top of the vertical square tube 2, causing the flap wheel 8 or wire wheel 9 protruding from the bottom opening of the protective cover 10 to contact the surface of the manhole cover. The high-speed rotating flap wheel 8 or wire wheel 9 grinds the surface of the manhole cover. The protective cover 10 effectively blocks flying debris and sparks during the grinding process, ensuring operational safety. During the grinding process, the air extraction connector 1101 on the dust collection box 11 is connected to an external air source device such as a vacuum cleaner. The negative pressure generated by the air source device draws the grinding debris and dust into the dust collection boxes 11 on both sides of the protective cover 10. The filter components inside the dust collection box 11 act as interceptors, and the metal filter 1103 fixed to the outer frame 1102 effectively blocks large particles of sparks and debris, preventing them from entering the external vacuum equipment and causing damage. This achieves timely collection and purification of debris during the grinding process, reducing environmental pollution and protecting the health of the operators.

Claims

1. A grinding device for ductile iron manhole covers, characterized in that: The system includes a horizontal square tube (1) and a vertical square tube (2). The vertical square tube (2) is located at the rear end of the horizontal square tube (1) and is fixedly connected to the horizontal square tube (1). A handle (201) is fixedly installed at the top of the rear end of the vertical square tube (2). A support leg (3) is vertically slidably installed inside the vertical square tube (2) by means of a linear drive assembly. The support leg (3) extends out of the bottom end of the vertical square tube (2) and is fixedly installed with an auxiliary wheel (4). A support wheel (5) is fixedly installed at the bottom of the front end of the horizontal square tube (1). A power structure is fixedly installed on one side of the horizontal square tube (1), and a shell (6) is fixedly installed on the other side. The shell (6) extends downward and protrudes from the bottom surface of the horizontal square tube (1). The shell (6) integrates... There is a transmission assembly, the output shaft of the power structure passes through the housing (6) and is driven and installed with the transmission assembly, and a drive shaft (7) is driven and installed on the transmission assembly. The drive shaft (7) passes through the housing (6) and extends to the bottom of the horizontal square tube (1), and a flap wheel (8) or a wire wheel (9) is detachably installed. A protective cover (10) with a bottom opening is fixedly installed at the bottom end of the horizontal square tube (1). The protective cover (10) covers the flap wheel (8) or the wire wheel (9), and the flap wheel (8) or the wire wheel (9) protrudes from the protective cover (10). A dust collection box (11) is fixedly installed on both sides of the protective cover (10), and an air suction connector (1101) is connected to the dust collection box (11).

2. The grinding device for ductile iron manhole covers according to claim 1, characterized in that: The linear drive assembly includes a through hole (301) coaxially opened on the support (3), a screw nut (302) fixedly installed in the through hole (301), and a screw rod (203) connected to the screw nut (302); an end cap (202) is fixedly installed at the top of the vertical square tube (2), the top of the screw rod (203) coaxially passes through the end cap (202) and is rotatably installed with the end cap (202), and a handwheel (2031) is fixedly installed at the top of the screw rod (203).

3. A grinding device for ductile iron manhole covers according to claim 1, characterized in that: The horizontal square tube (1) is provided with mounting panels (101) on both sides. The mounting panels (101) are fixed to the horizontal square tube (1) by bolts, and the power structure and the outer shell (6) are fixedly installed to the mounting panels (101) respectively.

4. A grinding device for ductile iron manhole covers according to claim 3, characterized in that: The power structure includes a servo motor (102), which is fastened to one of the mounting panels (101) by bolts. The output shaft of the servo motor (102) passes through the horizontal square tube (1) and the mounting panel (101) and is inserted into the housing (6).

5. A grinding device for ductile iron manhole covers according to claim 4, characterized in that: Both the outer shell (6) and the mounting panel (101) are made of stainless steel. The outer shell (6) and the mounting panel (101) are welded and fixed, and the outer shell (6) is fastened to the protective cover (10) by bolts.

6. A grinding device for ductile iron manhole covers according to claim 5, characterized in that: The outer casing (6) includes a stainless steel housing (601) fixedly connected to the mounting panel (101) and the protective cover (10), the transmission assembly is integrated inside the housing (601), and a cover (602) is detachably installed on the outside of the housing (601) by bolts.

7. A grinding device for ductile iron manhole covers according to claim 6, characterized in that: The transmission assembly includes a transmission belt (6011) and a pulley (6012) that are matched together. The pulley (6012) is respectively located on the output shaft and the drive shaft (7) inside the housing (601).

8. A grinding device for ductile iron manhole covers according to claim 1, characterized in that: The free end of the drive shaft (7) is threaded with a clamping nut (701), which abuts against the end face of the flap wheel (8) or the wire wheel (9), and the front of the protective cover (10) is provided with a notch (1001) that matches the clamping nut (701).

9. A grinding device for ductile iron manhole covers according to claim 1, characterized in that: The dust collection box (11) is detachably connected to at least one layer of filter assembly. The filter assembly includes an outer frame (1102) that is interference-fitted to the inner wall of the dust collection box (11). A metal filter screen (1103) is provided inside the outer frame (1102).

10. A grinding device for ductile iron manhole covers according to claim 1, characterized in that: The vertical square tube (2) is fitted with a wear-resistant bushing (204), and the wear-resistant bushing (204) is slidably connected to the support leg (3).

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