Surface polishing device for PVC profile pipe production and processing

CN224643252UActive Publication Date: 2026-08-18HENAN JUAI PIPE TECH CO LTD
View PDF 0 Cites 0 Cited by

Patent Information

Application Number
CN202522073150.1
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2025-09-26
Publication Date
2026-08-18
Estimated Expiration
2035-09-26

AI Technical Summary

Technical Problem

[0002]PVC型材管材是一种以聚氯乙烯树脂为主要原料制成的塑料管道制品,具有耐腐蚀、重量轻、抗压性强和安装便捷等特点,广泛应用于输水、排水、灌溉及电力穿线等领域,PVC型材管材在加工过程中,要对表面进行抛光加工,需要用到PVC型材管材生产加工用表面抛光装置,现有的PVC型材管材生产加工用表面抛光装置多由外圆抛光机组成,外圆抛光机主要由导轮、抛光轮、驱动辊、机身框架等组成,基于无心磨原理工作,工作时,PVC型材管材被自动向前传送,这个过程中,依靠导轮倾斜角度产生的摩擦力分量来推动PVC型材管材移动,当导轮向出口方向倾斜时,PVC型材管材在摩擦力的轴向分力作用下自动向出口方向移动,当导轮向入口方向倾斜时,PVC型材管材自动向入口方向移动,同时,PVC型材管材经过抛光轮时,高速旋转的抛光轮对PVC型材管材表面进行打磨、抛光和拉丝表面处理,操作简便高效,传统的‌PVC型材管材生产加工用表面抛光装置工作时,导轮的倾斜方向会被预先设定,当PVC型材管材需要进行二次表面处理时,需要将PVC型材管材从设备出口取出,然后再放入入口处进行二次加工,想要改变导轮方向时,需要先停机,然后手动依次调整各个导轮的倾斜方向,颇为不便,为此,我们提出一种PVC型材管材生产加工用表面抛光装置

Benefits of technology

[0010]进一步的,还包括单片机,所述单片机设置于顶盖的右侧后端,单片机的输入端电连接外部电源,为PVC型材管材表面的抛光加工提供控制效果。

✦ Generated by Eureka AI based on patent content.

Smart Images

  • Figure CN224643252U_ABST
    Figure CN224643252U_ABST
Patent Text Reader

Abstract

The utility model discloses a kind of surface polishing devices for PVC profile pipe production and processing, including base and adjustable feeding mechanism, base: its upper end is equipped with top cover, the upper end middle part of base is equipped with mounting plate, adjustable feeding mechanism: it includes sliding plate, guide wheel, limit plate, limit inclined groove and limit column, the sliding plate is evenly slidably connected in the inside of mounting plate, guide wheel is all set in the upper end right side of sliding plate, limit plate is slidably connected in the inside upper end left side of mounting plate, this surface polishing device for PVC profile pipe production and processing is equipped with two groups of guide wheel of opposite oblique direction, the surface contact and separation of guide wheel of different oblique direction and PVC profile pipe by moving limit plate can be realized, the longitudinal movement of PVC profile pipe, avoid the situation of stop machine manual adjustment guide wheel orientation occurs, and can repeatedly surface processing to PVC profile pipe, improve the processing efficiency of PVC profile pipe.
Need to check novelty before this filing date? Find Prior Art

Description

Technical Field

[0001] This utility model relates to the field of PVC profile and pipe production technology, specifically to a surface polishing device for PVC profile and pipe production and processing. Background Technology

[0002] PVC profile pipes are plastic pipe products made primarily of polyvinyl chloride resin. They are characterized by corrosion resistance, light weight, high pressure resistance, and easy installation, and are widely used in water supply, drainage, irrigation, and electrical wiring. During the processing of PVC profile pipes, surface polishing is required, necessitating the use of surface polishing equipment. Existing surface polishing equipment for PVC profile pipe production often consists of an external cylindrical polishing machine. This machine mainly comprises guide wheels, polishing wheels, drive rollers, and a machine frame. It operates based on the principle of centerless grinding. During operation, the PVC profile pipe is automatically conveyed forward. In this process, the frictional force generated by the tilt angle of the guide wheels propels the PVC profile pipe. When the guide wheels tilt towards the outlet direction, the PVC profile pipe... Under the axial component of friction, the PVC profile automatically moves towards the outlet. When the guide wheel tilts towards the inlet, the PVC profile automatically moves towards the inlet. Simultaneously, as the PVC profile passes the polishing wheel, the high-speed rotating polishing wheel grinds, polishes, and brushes the surface of the PVC profile. The operation is simple and efficient. In traditional PVC profile production and processing surface polishing devices, the tilt direction of the guide wheel is preset. When the PVC profile needs secondary surface treatment, it is necessary to take the PVC profile out from the equipment outlet and then put it into the inlet for secondary processing. If you want to change the direction of the guide wheel, you need to stop the machine first and then manually adjust the tilt direction of each guide wheel in turn, which is quite inconvenient. Therefore, we propose a surface polishing device for PVC profile production and processing. Utility Model Content

[0003] The technical problem to be solved by this utility model is to overcome the existing defects and provide a surface polishing device for the production and processing of PVC profile pipes. It is equipped with two sets of guide wheels with opposite inclination directions. By moving the limiting plate, the guide wheels with different inclination directions can contact and separate from the surface of the PVC profile pipe, realizing the longitudinal movement of the PVC profile pipe. This avoids the need to manually adjust the orientation of the guide wheels when the machine stops, and can repeatedly process the surface of the PVC profile pipe, improving the processing efficiency of PVC profile pipes. It can effectively solve the problems in the background art.

[0004] To achieve the above objectives, this utility model provides the following technical solution: a surface polishing device for the production and processing of PVC profiles and pipes, comprising a base and an adjustable feeding mechanism; Base: It has a top cover at the top and a mounting plate at the middle of the upper part of the base; Adjustable feeding mechanism: It includes a sliding plate, guide wheels, a limiting plate, limiting grooves, and limiting posts. The sliding plate is uniformly slidably connected to the inside of the mounting plate. The guide wheels are all located on the upper right side of the sliding plate. The limiting plate is slidably connected to the upper left side of the inside of the mounting plate. The limiting grooves are uniformly opened in the middle of the inside of the limiting plate. The limiting posts are all located on the upper left side of the sliding plate. The outer surface of the limiting posts is slidably connected to the inner wall of the vertically adjacent limiting grooves. The inclination directions of two vertically adjacent limiting grooves are opposite. The inclination direction of the guide wheels is the same as the inclination direction of the horizontally adjacent limiting grooves, providing a basis for changing the movement direction of the PVC profile pipe. It is equipped with two sets of guide wheels with opposite inclination directions. By moving the limiting plate, the guide wheels with different inclination directions can contact and separate from the surface of the PVC profile pipe, realizing the longitudinal movement of the PVC profile pipe. This avoids the need to manually adjust the orientation of the guide wheels when stopping the machine, and allows for repeated surface processing of the PVC profile pipe, improving the processing efficiency of the PVC profile pipe.

[0005] Furthermore, the adjustable feeding mechanism also includes an electric push rod, which is located at the middle of the upper front side of the base. The input end of the electric push rod is electrically connected to the output end of the microcontroller, and the upper end of the telescopic end of the electric push rod is fixedly connected to the lower front side of the limiting plate, providing a driving effect for changing the moving direction of the PVC profile pipe.

[0006] Furthermore, the adjustable feeding mechanism also includes a drive assembly, which includes a sliding frame, a drive roller, a support wheel, a lead screw, and a handwheel. The sliding frame is slidably connected to the upper right side of the base, the drive roller is rotatably connected to the inner middle of the sliding frame, the support wheels are respectively located on the left and right sides of the middle of the base, the lead screw is rotatably connected to the inner middle of the base, and the outer surface of the lead screw is threadedly connected to the inner lower middle of the sliding frame. The handwheel is located at the right end of the lead screw, providing a basis for the movement and support of PVC profiles of different diameters.

[0007] Furthermore, the driving component also includes a motor, which is located on the front side of the sliding frame. The input end of the motor is electrically connected to the output end of the microcontroller, and the rear end of the output end of the motor is fixedly connected to the front end of the driving roller, providing a driving effect for the movement of the PVC profile pipe.

[0008] Furthermore, it also includes a mounting bracket, a fixing bracket, polishing wheels, and a second motor. The mounting brackets are evenly arranged on the upper left side of the base, and the fixing brackets are rotatably connected to the inner right side of the mounting brackets. The polishing wheels are all arranged on the outer front side of the fixing brackets. Rotatable sprockets are provided on both the left and right sides of the rear end of the mounting brackets. The second motor is located on the upper front side of the mounting brackets. The input end of the second motor is electrically connected to the output end of the microcontroller. Two horizontally adjacent sprockets are connected by sprocket drive. The rear end of the fixing bracket is fixedly connected to the front end of the vertically adjacent sprocket. The rear end of the input end of the second motor is fixedly connected to the front end of the vertically adjacent sprocket, providing a foundation for the polishing of the PVC profile pipe surface.

[0009] Furthermore, it also includes inspection doors, all of which are hinged to the middle right side of the top cover. The inspection doors are vertically aligned with the polishing wheels. Each inspection door has an acrylic plate in the middle of its interior and a handle in the middle of the lower right side to facilitate the disassembly and assembly of different polishing wheels.

[0010] Furthermore, it also includes a microcontroller, which is located at the rear right side of the top cover. The input terminal of the microcontroller is electrically connected to an external power supply to provide control for the polishing process of the PVC profile pipe surface.

[0011] Compared with the prior art, the beneficial effects of this utility model are as follows: This surface polishing device for PVC profile pipe production and processing has the following advantages: The movement of the limiting plate drives the movement of the limiting grooves in different inclination directions, enabling the extension and retraction of guide wheels in different directions. This allows the guide wheels in different directions to contact and separate from the surface of the PVC profile pipe, thereby achieving rapid adjustment of the movement direction of the PVC profile pipe. The surface of the PVC profile pipe can be polished repeatedly without secondary feeding or machine stoppage for reversal, thus improving the polishing efficiency of the PVC profile pipe. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the adjustable feeding mechanism of this utility model; Figure 3 This is a schematic cross-sectional view of the adjustable feeding mechanism of this utility model; Figure 4 This is a schematic diagram of the sprocket structure of this utility model; Figure 5 This is a schematic diagram of the structure of the sliding plate and guide wheel of this utility model.

[0013] In the diagram: 1. Base, 2. Top cover, 3. Mounting plate, 4. Adjustable feeding mechanism, 41. Sliding plate, 42. Guide wheel, 43. Limiting plate, 44. Limiting groove, 45. Limiting column, 46. Electric push rod, 47. Drive assembly, 471. Sliding frame, 472. Drive roller, 473. Support wheel, 474. Lead screw, 475. Handwheel, 476. Motor 1, 5. Inspection door, 6. Mounting bracket, 7. Fixing bracket, 8. Polishing wheel, 9. Sprocket, 10. Motor 2, 11. Microcontroller. Detailed Implementation

[0014] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0015] Please see Figure 1-5 This embodiment provides a technical solution: a surface polishing device for the production and processing of PVC profiles and pipes, including a base 1 and an adjustable feeding mechanism 4; Base 1: It has a top cover 2 at its upper end, and a mounting plate 3 at the middle of its upper end. It also includes a mounting bracket 6, a fixing bracket 7, polishing wheels 8, and a motor 10. The mounting brackets 6 are evenly distributed on the upper left side of the base 1. The fixing brackets 7 are rotatably connected to the inner right side of the mounting brackets 6. The polishing wheels 8 are all located on the outer front side of the fixing brackets 7. The polishing wheels 8 can be made of nylon or cloth and can be replaced according to actual needs. The front side of each fixing bracket 7 has a positioning pin, and the inner center of each polishing wheel 8 has a insertion hole. The inner wall of the insertion hole is aligned with the longitudinal direction. The outer surface of the adjacent positioning pins is inserted, and the inner front side of the positioning pin located in the middle is threaded with an internal hex bolt. The rear end of the bolt head of the internal hex bolt is fixedly connected to the front end of the vertically adjacent polishing wheel 8. A cooling pipe can also be added to the upper end of the mounting bracket 6. The outlet of the cooling pipe is aligned with the right side of the polishing wheel 8. When the polishing wheel 8 contacts the surface of the PVC profile pipe, the cooling pipe can continuously spray cooling water onto the surface of the PVC profile pipe, reducing the heat accumulation on the surface of the PVC profile pipe. Rotatable... Both sprocket 9 and motor 10 are located on the upper front side of the mounting bracket 6. The input end of motor 10 is electrically connected to the output end of microcontroller 11. Two horizontally adjacent sprockets 9 are connected by sprocket drive. The rear end of the fixing bracket 7 is fixedly connected to the front end of the vertically adjacent sprocket 9. The rear end of the input end of motor 10 is fixedly connected to the front end of the vertically adjacent sprocket 9, providing a foundation for the polishing of the PVC profile pipe surface. It also includes an inspection door 5, which is hinged to the middle right side of the top cover 2. The inspection door 5 is connected to... The polishing wheels 8 are vertically aligned, and each inspection door 5 has an acrylic plate in the middle of its interior. Each inspection door 5 has a handle in the middle of its lower right side. The inspection door 5 can be opened and closed by the handle, allowing for the removal and replacement of the polishing wheels 8. The polishing status of the PVC profile pipe can also be observed through the transparent acrylic plate. This is used for the removal and installation of different polishing wheels 8. The system also includes a microcontroller 11, which is located at the rear right side of the top cover 2. The input terminal of the microcontroller 11 is electrically connected to an external power supply to provide control for the polishing process of the PVC profile pipe surface. Adjustable feeding mechanism 4: It includes a sliding plate 41, guide wheels 42, a limiting plate 43, limiting grooves 44, and limiting posts 45. The sliding plate 41 is evenly slidably connected to the inside of the mounting plate 3. The guide wheels 42 are all located on the upper right side of the sliding plate 41. The limiting plate 43 is slidably connected to the upper left side of the inside of the mounting plate 3. The limiting grooves 44 are evenly opened in the middle of the inside of the limiting plate 43. The limiting posts 45 are all located on the upper left side of the sliding plate 41. The outer surface of the limiting posts 45 is slidably connected to the inner wall of the vertically adjacent limiting grooves 44. The inclination directions of two vertically adjacent limiting grooves 44 are opposite. The inclination direction of the guide wheels 42 is the same as the inclination direction of the horizontally adjacent limiting grooves 44. The adjustable feeding mechanism 4 also includes an electric push rod 46, which is located at the middle of the upper front side of the base 1. The input end of the electric push rod 46 is electrically connected to the output end of the microcontroller 11, and the upper end of the telescopic end of the electric push rod 46 is fixedly connected to the lower front side of the limiting plate 43, providing a driving effect for changing the movement direction of the PVC profile pipe. The adjustable feeding mechanism 4 also includes a drive assembly 47, which includes a sliding frame 471, a drive roller 472, a support wheel 473, a lead screw 474, and a handwheel 475. The sliding frame 471 is slidably connected to the upper right side of the base 1, and the drive roller 472 is rotatably connected to the sliding frame 471. Inside, both the guide wheel 42 and the drive roller 472 can be made of polyurethane. Support wheels 473 are respectively located on the left and right sides of the base 1 at its central position. The lead screw 474 is rotatably connected to the center of the base 1. The outer surface of the lead screw 474 is threadedly connected to the lower center of the sliding frame 471. A corrugated tube can be added between the inner wall of the base 1 and the left and right sides of the sliding frame 471. The corrugated tube is fitted onto the outer surface of the lead screw 474 and will contract and expand as the sliding frame 471 moves left and right, protecting the lead screw 474 from external environmental influences. A handwheel 475 is located at the right end of the lead screw 474, providing a foundation for the movement and support of PVC profiles of different diameters. The drive assembly 47... It also includes a motor 476, which is located on the front side of the sliding frame 471. The input end of the motor 476 is electrically connected to the output end of the microcontroller 11. The rear end of the output end of the motor 476 is fixedly connected to the front end of the drive roller 472, providing a driving effect for the movement of the PVC profile pipe. It is equipped with two sets of guide wheels 42 with opposite tilt directions. By moving the limiting plate 43, the guide wheels 42 with different tilt directions can contact and separate from the surface of the PVC profile pipe, realizing the longitudinal movement of the PVC profile pipe. This avoids the need to manually adjust the orientation of the guide wheels 42 when the machine stops, and allows for repeated surface processing of the PVC profile pipe, improving the processing efficiency of the PVC profile pipe.

[0016] The working principle of the surface polishing device for PVC profile pipe production and processing provided by this utility model is as follows: Before polishing the surface of the PVC profile pipe, an adjustment is performed. Rotating the handwheel 475 drives the lead screw 474 to rotate. When the lead screw 474 rotates clockwise, the sliding frame 471 moves to the left, driving the drive roller 472 to the left. The distance between the drive roller 472 and the guide wheel 42 decreases, which is suitable for PVC profile pipes with smaller diameters. When the lead screw 474 rotates counterclockwise, the sliding frame 471 moves to the right, driving the drive roller 472 to the right. The distance between the drive roller 472 and the guide wheel 42 increases, which is suitable for PVC profile pipes with larger diameters. Adjusting the sliding frame 471 and the drive roller 472 to appropriate positions, so that the guide wheel 42 and the drive roller 472 are aligned... 2 and polishing wheel 8 can simultaneously contact the surface of the PVC profile pipe. Then, the PVC profile pipe is inserted from the rear side of the top cover 2, so that the guide wheel 42, drive roller 472 and polishing wheel 8 contact the surface of the PVC profile pipe. At this time, the sliding plate 41 with the forward-tilted guide wheel 42 is in the extended state and in contact with the surface of the PVC profile pipe. When the equipment is working, the PVC profile pipe will move forward. The microcontroller 11 controls the motor 476 to run. The output shaft of the motor 476 drives the drive roller 472 to rotate, which in turn drives the PVC profile pipe to rotate. The guide wheel 42 also rotates accordingly. When the guide wheel 42 rotates, the tilt angle will generate a friction component, thereby pushing the PVC profile pipe forward. At the same time, the microcontroller 11 controls the motor 2 When motor 10 operates, the output shaft of motor 10 drives the fixed frame 7 to rotate via sprocket 9 and chain transmission. The polishing wheel 8 also rotates at high speed. When the PVC profile pipe passes through the polishing wheel 8, the high-speed rotating polishing wheel 8 contacts the surface of the PVC profile pipe, creating a polishing effect. After the PVC profile pipe passes through three polishing wheels 8, a second polishing is required to improve the polishing quality. At this time, the microcontroller 11 controls the electric push rod 46 to work. The telescopic end of the electric push rod 46 extends forward, driving the limiting plate 43 forward. As the limiting plate 43 moves forward, the limiting groove 44 also moves forward, pressing the corresponding limiting post 45. When the forward-tilting limiting groove 44 moves, the corresponding limiting post 45 moves to the left, and the corresponding... As the sliding plate 41 and the forward-tilting guide wheel 42 move to the left, and the backward-tilting limiting groove 44 moves, the corresponding limiting post 45 moves to the right, and the corresponding sliding plate 41 and the backward-tilting guide wheel 42 also move to the right. At this time, the PVC profile pipe will not move due to the limiting effect of the drive roller 472 and the front support wheel 473. The guide wheel 42, which was originally in contact with the surface of the PVC profile pipe and tilted forward, retracts to the left and separates from the surface of the PVC profile pipe. The guide wheel 42, which was originally not in contact with the surface of the PVC profile pipe and tilted backward, retracts to the right and contacts the surface of the PVC profile pipe. At this time, when the drive roller 472 rotates, the PVC profile pipe will move backward and be polished again by the high-speed rotating polishing wheel 8. This process is repeated.It can automatically and quickly adjust the movement direction of PVC profile pipes, and can repeatedly polish the surface of PVC profile pipes without secondary feeding, thus improving the polishing efficiency of PVC profile pipes.

[0017] It is worth noting that the microcontroller 11 disclosed in the above embodiments is an STM32F405RGT6 microcontroller, the electric actuator 46 is an NKLA36 electric actuator, the first motor 476 is a 2BLD10-24GN-20S motor, and the second motor 10 is a Y2-280S-8 motor. The microcontroller 11 controls the operation of the electric actuator 46, the first motor 476, and the second motor 10 using methods commonly used in the prior art.

[0018] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the content of this utility model specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A surface polishing device for the production and processing of PVC profiles and pipes, characterized in that: Includes a base (1) and an adjustable feeding mechanism (4); Base (1): It is provided with a top cover (2) at its upper end, and a mounting plate (3) is provided at the middle of the upper end of the base (1). Adjustable feeding mechanism (4): It includes a sliding plate (41), a guide wheel (42), a limiting plate (43), a limiting groove (44), and a limiting post (45). The sliding plate (41) is evenly slidably connected to the inside of the mounting plate (3). The guide wheel (42) is set on the upper right side of the sliding plate (41). The limiting plate (43) is slidably connected to the upper left side of the inside of the mounting plate (3). The limiting groove (44) is evenly opened in the middle of the inside of the limiting plate (43). The limiting post (45) is set on the upper left side of the sliding plate (41). The outer surface of the limiting post (45) is slidably connected to the inner wall of the vertically adjacent limiting groove (44). The inclination directions of the two vertically adjacent limiting grooves (44) are opposite. The inclination direction of the guide wheel (42) is the same as the inclination direction of the horizontally adjacent limiting groove (44).

2. The surface polishing device for PVC profile pipe production and processing according to claim 1, characterized in that: It also includes a microcontroller (11), which is located at the rear right side of the top cover (2), and the input terminal of the microcontroller (11) is electrically connected to an external power supply.

3. The surface polishing device for PVC profile pipe production and processing according to claim 2, characterized in that: The adjustable feeding mechanism (4) also includes an electric push rod (46), which is located at the middle of the upper front side of the base (1). The input end of the electric push rod (46) is electrically connected to the output end of the microcontroller (11), and the upper end of the telescopic end of the electric push rod (46) is fixedly connected to the lower front side of the limiting plate (43).

4. The surface polishing device for PVC profile pipe production and processing according to claim 2, characterized in that: The adjustable feeding mechanism (4) further includes a drive assembly (47), which includes a sliding frame (471), a drive roller (472), a support wheel (473), a lead screw (474), and a handwheel (475). The sliding frame (471) is slidably connected to the upper right side of the base (1), the drive roller (472) is rotatably connected to the middle of the sliding frame (471), the support wheel (473) is respectively located on the left and right sides of the middle of the base (1), the lead screw (474) is rotatably connected to the middle of the base (1), the outer surface of the lead screw (474) is threadedly connected to the middle of the lower end of the sliding frame (471), and the handwheel (475) is located at the right end of the lead screw (474).

5. The surface polishing device for PVC profile pipe production and processing according to claim 4, characterized in that: The drive assembly (47) also includes a motor (476), which is located on the front side of the sliding frame (471). The input end of the motor (476) is electrically connected to the output end of the microcontroller (11), and the rear end of the output end of the motor (476) is fixedly connected to the front end of the drive roller (472).

6. The surface polishing device for PVC profile pipe production and processing according to claim 2, characterized in that: It also includes a mounting bracket (6), a fixing bracket (7), a polishing wheel (8), and a second motor (10). The mounting bracket (6) is evenly arranged on the upper left side of the base (1). The fixing bracket (7) is rotatably connected to the inner right side of the mounting bracket (6). The polishing wheel (8) is arranged on the outer front side of the fixing bracket (7). Rotatable sprockets (9) are provided on the left and right sides of the rear end of the mounting bracket (6). The second motor (10) is arranged on the upper front side of the mounting bracket (6). The input end of the second motor (10) is electrically connected to the output end of the microcontroller (11). The two horizontally adjacent sprockets (9) are connected by sprocket transmission. The rear end of the fixing bracket (7) is fixedly connected to the front end of the vertically adjacent sprocket (9). The rear end of the input end of the second motor (10) is fixedly connected to the front end of the vertically adjacent sprocket (9).

7. The surface polishing device for PVC profile pipe production and processing according to claim 6, characterized in that: It also includes an inspection door (5), which is hinged to the middle right side of the top cover (2) by a hinge. The inspection door (5) is vertically aligned with the polishing wheel (8). An acrylic plate is provided in the middle of the interior of the inspection door (5), and a handle is provided in the middle of the lower right side of the inspection door (5).