A belt grinder for grinding iron tower components

Abstract

The present invention relates to the technical field of grinding equipment, and in particular to a sanding belt grinder for grinding iron tower components, comprising a sanding belt, two rotating drums and a supporting structure located on the inner side of the sanding belt, wherein the sanding belt is sleeved on the two rotating drums and is synchronously driven, the sanding belt is horizontal, and the supporting structure is used to lift the upper part of the sanding belt so that a grinding plane is formed on the upper surface of the sanding belt; the supporting structure comprises two side plates distributed front and back and a plurality of supporting plates between the two side plates, the length direction of the side plates is horizontal, and capsule-shaped guide grooves are provided on the side walls of the side plates; through the dynamic supporting structure, relative movement is no longer generated between the sanding belt and the supporting plate, thereby greatly reducing the friction between the two, and the design of reducing friction prolongs the service life of the sanding belt and the supporting plate, reduces the replacement frequency, and reduces the maintenance cost. At the same time, because the energy loss caused by friction is reduced, the energy utilization rate is improved.

Description

Technical Field

[0001] The invention relates to the technical field of grinding equipment, in particular to an abrasive belt grinder for grinding iron tower components. Background Art

[0002] With the continuous development of the power industry and the improvement of power grid construction, the demand for power towers continues to grow. As an important part of the transmission line, the manufacturing quality of power towers directly affects the safe and stable operation of the entire power grid. In the production process of power towers, the surface treatment of tower components is particularly important, which not only affects the appearance quality of the tower, but also is related to the corrosion resistance and service life of the tower during long-term outdoor use.

[0003] At present, the surface treatment of power tower components is mainly carried out by mechanical grinding. Among them, belt grinders, as a high-efficiency surface treatment equipment, have been widely used in the power tower manufacturing industry. Although traditional belt grinders can meet basic grinding needs, there are still some problems in actual operation. For example, when the sanding belt rotates at high speed, it mainly relies on the bottom support plate to lift the sanding belt, so that the sanding belt can form a grinding surface to perform flat grinding on the workpiece. Due to the friction generated by the relative movement between the sanding belt and the support plate, when the sanding belt runs for a long time, the support plate and the sanding belt will be worn and damaged, resulting in a decrease in its service life, and affecting the flatness of the support plate surface, thereby affecting the flatness of the grinding surface formed by the sanding belt. At the same time, the friction between the sanding belt and the support plate will consume the sanding belt energy, resulting in energy loss. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a belt grinder for grinding iron tower components, and the specific technical solution adopted is:

[0005] A sanding belt grinder for grinding an iron tower assembly comprises a sanding belt, two rotating drums and a supporting structure located inside the sanding belt. The sanding belt is sleeved on the two rotating drums and is synchronously driven. The sanding belt is horizontal. The supporting structure is used to lift the upper part of the sanding belt so that the upper surface of the sanding belt forms a grinding plane.

[0006] The conveying structure includes two side plates distributed front and back and a plurality of supporting plates between the two side plates, the length direction of the side plates is horizontal, a capsule-shaped guide groove is provided on the side wall of the side plates, and the plurality of supporting plates are distributed in a capsule shape in the horizontal direction, a connecting plate is fixed at both ends of each supporting plate, two first sliding columns are fixed on the connecting plate, the connecting line of the two first sliding columns is parallel to the surface where the supporting plate is located, and the first sliding column is slidably installed in the capsule-shaped guide groove;

[0007] Among them, when multiple support plates move along the capsule-shaped guide groove track, multiple support plates on the upper side of the side plate form a complete plane, and the complete plane lifts the upper part of the sanding belt, and the vertical cross-sectional shape of the support plate along its width direction is Z-shaped.

[0008] Furthermore, two adjacent connecting plates in the conveying structure are connected by a spring.

[0009] Furthermore, a power wheel is rotatably arranged on the side plate, a plurality of levers are arranged on the circumferential outer wall of the power wheel, one end of the lever is slidably inserted into the power wheel along the radial direction of the power wheel, a slot is arranged at the other end of the lever, and the lever is connected to the power wheel via a spring sheet;

[0010] A shifting post is arranged on the side wall of each connecting plate, and the shifting post is used in cooperation with the clamping groove on the shifting rod.

[0011] Furthermore, an outer box body is provided on the outside of the sanding belt, a processing opening is opened on the top of the outer box body, a filling column is fixed in the middle of the rotating drum, a support shaft is fixedly inserted in the middle of the filling column, the support shaft is rotatably installed on the inner wall of the outer box body, a main motor for providing power to a support shaft is provided on the outer wall of the outer box body, and the side panel is fixedly connected to the outer box body through a fixing plate.

[0012] Furthermore, two pressing rollers are rotatably arranged in the outer box body, and the two pressing rollers are in contact with the plane on the upper side of the sanding belt.

[0013] Furthermore, a plurality of retaining columns are arranged on the front and rear outer walls of the rotating drum outside the sanding belt, and a clamping groove for clamping the edge of the sanding belt is opened on the circumferential outer wall of the retaining column.

[0014] Furthermore, each of the blocking columns is provided with a sliding block, which is slidably mounted on the circumferential outer wall of the drum along the axial direction of the drum.

[0015] Furthermore, both ends of the rotating drum are provided with fixing rings, the fixing rings are separated from the rotating drum, the fixing rings are fixed on the inner wall of the outer box body, an annular groove is opened on the inner wall of the fixing ring, the annular groove is composed of a first arc groove, a second arc groove and two transition grooves, a second sliding column is slidingly arranged in the annular groove, the second sliding column and the sliding block are connected by a connecting rod, when the second sliding column slides in the first arc groove, the blocking column approaches the sanding belt, and when the second sliding column slides in the second arc groove, the blocking column is separated from the sanding belt.

[0016] The advantages of the present invention are:

[0017] Through the dynamic lifting structure, there is no relative movement between the sanding belt and the support plate, thereby greatly reducing the friction between the two. This friction-reducing design prolongs the service life of the sanding belt and the support plate, reduces the replacement frequency, and reduces maintenance costs. At the same time, it improves energy utilization because it reduces energy loss caused by friction. The design of the supporting structure ensures that the sanding belt always remains flat in the working state, and can maintain a stable grinding surface even when it is under pressure from the workpiece, thereby improving the grinding quality. Through the synchronous movement between the support plate and the sanding belt, unnecessary interference factors are reduced, making the grinding process smoother and more controllable. At the same time, the stable grinding surface helps to improve the grinding accuracy and consistency, which is especially important for power tower components that require high-quality surface treatment. In summary, this innovative sanding belt grinder design effectively improves the grinding efficiency and quality by improving the relative movement between the sanding belt and the support plate, while reducing energy consumption and maintenance costs. It is an important advancement for the power tower manufacturing industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a schematic diagram of the structure of the present invention;

[0020] Figure 2 yes Figure 1 Schematic diagram of the internal structure of the middle and outer boxes;

[0021] Figure 3 yes Figure 2 Schematic diagram of the enlarged structure of the medium sand belt;

[0022] Figure 4 yes Figure 3 A schematic diagram of the enlarged structure of the rotating drum in a sectional view and a top view;

[0023] Figure 5 yes Figure 4 Schematic diagram of the cross-section structure;

[0024] Figure 6 yes Figure 5 A schematic diagram of the enlarged structure of the middle fixing ring;

[0025] Figure 7 yes Figure 2 An enlarged schematic diagram of the mid-carrying structure;

[0026] Figure 8 yes Figure 7 A schematic diagram of the enlarged structure of the middle side panel;

[0027] Fig. 9 yes Figure 7 A schematic diagram of the enlarged structure of the middle power wheel;

[0028] Figure numerals: 1. abrasive belt; 2. rotating drum; 3. side plate; 4. capsule-shaped guide groove; 5. support plate; 6. connecting plate; 7. first sliding column; 8. spring; 9. power wheel; 10. lever; 11. spring piece; 12. outer box body; 13. filling column; 14. supporting shaft; 15. main motor; 16. fixed plate; 17. pressure roller; 18. stop column; 19. slot; 20. slider; 21. connecting rod; 22. second sliding column; 23. fixing ring; 24. first arc groove; 25. second arc groove; 26. transition groove; 27. lever. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0030] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by “center”, “up”, “down”, “left”, “right”, “vertical”, “horizontal”, “inside” and “outside”, etc., are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0031] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. This embodiment is written in a progressive manner.

[0032] like Figures 1 to 9 As shown, a belt grinder for grinding an iron tower assembly of the present invention comprises a belt 1, two rotating drums 2 and a supporting structure located inside the belt 1. The belt 1 is sleeved on the two rotating drums 2 and is synchronously driven. The belt 1 is horizontal. The supporting structure is used to lift the upper part of the belt 1 so that the upper surface of the belt 1 forms a grinding plane.

[0033] The conveying structure includes two side plates 3 distributed front and back and a plurality of supporting plates 5 between the two side plates 3. The length direction of the side plates 3 is horizontal. The side walls of the side plates 3 are provided with capsule-shaped guide grooves 4. The plurality of supporting plates 5 are distributed in a capsule shape in the horizontal direction. A connecting plate 6 is fixed at both ends of each supporting plate 5. Two first sliding columns 7 are fixed on the connecting plate 6. The connecting line of the two first sliding columns 7 is parallel to the surface where the supporting plates 5 are located. The first sliding columns 7 are slidably installed in the capsule-shaped guide grooves 4.

[0034] When the plurality of support plates 5 move along the trajectory of the capsule-shaped guide groove 4, the plurality of support plates 5 on the upper side of the side plate 3 form a complete plane, and the complete plane lifts the upper part of the sanding belt 1, and the vertical cross-sectional shape of the support plate 5 along its width direction is Z-shaped.

[0035] In detail, the abrasive belt 1 is supported and fixed by two rotating drums 2. When the rotating drum 2 rotates, it can drive the abrasive belt 1 to rotate. The shape of the abrasive belt 1 is capsule-shaped. The upper surface of the abrasive belt 1 is horizontal, and the workpiece is flat-ground by the upper surface of the abrasive belt 1. The supporting structure is located on the inner side of the abrasive belt 1 and is used to support the upper part of the abrasive belt 1, so that when the workpiece is ground on the upper surface of the abrasive belt 1, it is prevented from causing the upper surface of the abrasive belt 1 to be concave due to the downward pressure of the workpiece, so that the upper surface of the abrasive belt 1 cannot form a complete plane. The side plates 3 and the rubber on the supporting structure The capsule-shaped guide groove 4 is used to guide and support multiple pallets 5, that is, multiple pallets 5 move along the trajectory of the capsule-shaped guide groove 4, and the movement trajectory of multiple pallets 5 is also capsule-shaped. The multiple pallets 5 on the upper side of the side plate 3 can form a complete plane, and the complete plane is used to lift the upper part of the sanding belt 1. The connecting plate 6 can support the pallet 5. Since the two first sliding columns 7 on the connecting plate 6 slide in the capsule-shaped guide groove 4, the two first sliding columns 7 can be used to support and guide the pallet 5.

[0036] When grinding the workpiece, the drum 2 is rotated and multiple support plates 5 are moved on the side plate 3 along the trajectory of the capsule-shaped guide groove 4. The horizontal movement speed and direction of the support plates 5 on the upper side of the side plate 3 can be the same as the movement speed and direction of the upper part of the sanding belt 1. Therefore, the support plates 5 can lift the upper part of the sanding belt 1 while enabling it to move synchronously to avoid relative movement and friction, thereby realizing dynamic lifting of the upper part of the sanding belt 1.

[0037] Through the dynamic lifting structure, there is no relative movement between the sanding belt 1 and the support plate 5, thereby greatly reducing the friction between the two. This design of reducing friction prolongs the service life of the sanding belt 1 and the support plate 5, reduces the replacement frequency, and reduces maintenance costs. At the same time, because the energy loss caused by friction is reduced, the energy utilization rate is improved; the design of the supporting structure ensures that the sanding belt 1 always remains flat in the working state, and can maintain a stable grinding surface even when it is under pressure from the workpiece, thereby improving the grinding quality; through the synchronous movement between the support plate 5 and the sanding belt 1, unnecessary interference factors are reduced, making the grinding process smoother and more controllable, and at the same time, the stable grinding surface helps to improve the grinding accuracy and consistency, which is especially important for power tower components that require high-quality surface treatment; in summary, this innovative design of the sanding belt grinder effectively improves the grinding efficiency and quality by improving the relative movement between the sanding belt and the support plate, while reducing energy consumption and maintenance costs, which is an important progress for the power tower manufacturing industry.

[0038] Furthermore, two adjacent connecting plates 6 in the supporting structure are connected via a spring 8 .

[0039] In detail, since the moving trajectory of the pallet 5 is capsule-shaped, when the pallet 5 moves to the arc position at the end of the capsule, due to the guiding effect of the two first sliding columns 7 on the pallet 5, the distance and angle between the two adjacent pallets 5 will change. Therefore, the spring 8 can be used to achieve the connection between the two pallets 5, and at this time the spring 8 undergoes elastic deformation.

[0040] By connecting two adjacent pallets 5 through the spring 8, multiple pallets 5 can move synchronously when one pallet 5 is moved, thereby realizing the mutual connection of multiple pallets 5, and due to the elastic force of the spring 8, the multiple pallets 5 on the upper and lower sides of the side plate 3 are tightly abutted against each other, thereby maintaining the integrity of the plane where the multiple pallets 5 are spliced.

[0041] Furthermore, a power wheel 9 is rotatably provided on the side plate 3, and a plurality of levers 10 are provided on the circumferential outer wall of the power wheel 9. One end of the lever 10 is inserted into the power wheel 9 by sliding along the radial direction of the power wheel 9, and a slot is provided at the other end of the lever 10. The lever 10 is connected to the power wheel 9 through a spring sheet 11.

[0042] A shifting post 27 is disposed on the side wall of each connecting plate 6 , and the shifting post 27 cooperates with a slot on the shifting rod 10 for use.

[0043] In detail, the power wheel 9 is located at the arc center position of the end of the capsule-shaped motion trajectory of the support plate 5. The power wheel 9 can be powered by an electric motor. When the power wheel 9 rotates, it can drive multiple levers 10 and multiple spring pieces 11 to rotate synchronously. The spring pieces 11 generate elastic thrust on the lever 10 and make the slot at the end of the lever 10 snap into the lever column 27. As the power wheel 9 rotates, the lever 10 drives the connecting plate 6 to move in an arc through the lever column 27, thereby causing multiple support plates 5 to move along the capsule-shaped trajectory. Other levers 10 on the power wheel 9 push the lever columns 27 moved to the arc position of the capsule end one by one. When the lever columns 27 are away from the capsule-shaped arc end position, the lever 10 separates from the lever columns 27, thereby realizing continuous power supply to multiple support plates 5.

[0044] Furthermore, an outer box body 12 is provided on the outside of the sanding belt 1, a processing opening is opened on the top of the outer box body 12, a filling column 13 is fixed in the middle of the rotating drum 2, a support shaft 14 is fixedly inserted in the middle of the filling column 13, the support shaft 14 is rotatably installed on the inner wall of the outer box body 12, a main motor 15 for providing power to a support shaft 14 is provided on the outer wall of the outer box body 12, and the side panel 3 is fixedly connected to the outer box body 12 via a fixing plate 16.

[0045] In detail, the outer box body 12 is used to support and protect its internal structure. The processing opening on the outer box body 12 is used to expose a flat portion of the abrasive belt 1, so as to facilitate processing of the workpiece through the processing opening. The filling column 13 and the support shaft 14 can support the rotating drum 2. The main motor 15 provides power for the abrasive belt 1 and the rotating drum 2, and the fixed plate 16 provides support for the side plate 3.

[0046] Furthermore, two pressure rollers 17 are rotatably disposed in the outer box 12 , and the two pressure rollers 17 are in contact with the plane on the upper side of the abrasive belt 1 .

[0047] In detail, the two pressure rollers 17 are located within the lateral width interval of the movement trajectory of the multiple pallets 5. When the pallet 5 moves to the arc-shaped end of its trajectory, the pallet 5 performs an arc-shaped motion and the direction of the pallet 5 changes. Therefore, the end of the pallet 5 that is last separated from the abrasive belt 1 will tilt upward, that is, when the pallet 5 initially performs an arc-shaped motion, the end of the pallet 5 will lift the abrasive belt 1 a small distance, which can easily lead to the problem of uneven surface of the abrasive belt 1. The use of the two pressure rollers 17 can make the lifting position of the abrasive belt 1 by the pallet 5 be located outside the two pressure rollers 17, and the part of the abrasive belt 1 between the two pressure rollers 17 as the processing area always remains flat, thereby facilitating the limitation of the processing area of ​​the abrasive belt 1 and keeping the processing area flat at all times.

[0048] Furthermore, a plurality of retaining columns 18 are disposed on the front and rear outer walls of the rotating drum 2 outside the abrasive belt 1 , and a clamping groove 19 for clamping the edge of the abrasive belt 1 is opened on the circumferential outer wall of the retaining column 18 .

[0049] In detail, when the sanding belt 1 and the drum 2 are moving, the edge of part of the sanding belt 1 on the drum 2 will be stuck in the slot 19, so that the position of the sanding belt 1 on the drum 2 can be limited by the blocking column 18, and the edge of the sanding belt 1 can be shaped by the slot 19 to avoid the sanding belt 1 from warping.

[0050] Furthermore, each of the blocking columns 18 is provided with a sliding block 20 , and the sliding block 20 is slidably mounted on the circumferential outer wall of the rotating drum 2 along the axial direction of the rotating drum 2 .

[0051] In detail, since the retaining column 18 holds the sanding belt 1 in place through the slot 19, that is, the edge of the sanding belt 1 needs to enter the slot 19, when part of the sanding belt 1 moves onto the rotating drum 2 or part of the sanding belt 1 on the rotating drum 2 moves away from the rotating drum 2, the retaining column 18 needs to move away from the sanding belt 1 along the axial direction of the rotating drum 2, thereby facilitating the smooth separation of the edge of the sanding belt 1 on the inner side of the slot 19 from the retaining column 18, avoiding the sanding belt 1 and the retaining column 18 from being squeezed and damaged due to the restriction of the slot 19. The movement of the retaining column 18 is achieved by the slider 20.

[0052] Furthermore, both ends of the rotating drum 2 are provided with fixing rings 23, which are separated from the rotating drum 2 and fixed on the inner wall of the outer box body 12. An annular groove is opened on the inner wall of the fixing ring 23, which is composed of a first arc groove 24, a second arc groove 25 and two transition grooves 26. A second sliding column 22 is slidably provided in the annular groove, and the second sliding column 22 is connected to the slider 20 by a connecting rod 21. When the second sliding column 22 slides in the first arc groove 24, the blocking column 18 approaches the sanding belt 1, and when the second sliding column 22 slides in the second arc groove 25, the blocking column 18 is separated from the sanding belt 1.

[0053] In detail, when the drum 2 rotates, it can drive multiple sliders 20 and multiple blocking columns 18 to perform synchronous circular motion. The slider 20 will drive the second slider 22 to slide in the annular groove through the connecting rod 21. The distance between the first arc groove 24 and the sanding belt 1 is greater than the distance between the second arc groove 25 and the sanding belt 1. When the second slider 22 slides in the first arc groove 24, the slider 20 and the blocking column 18 thereon approach the sanding belt 1. At this time, the slot 19 on the blocking column 18 clamps the edge of the sanding belt 1. When the second slider 22 slides in the second arc groove 25, the blocking column 18 moves away from the sanding belt 1. The transition groove 26 is used to enable the second slider 22 to move smoothly between the first arc groove 24 and the second arc groove 25.

[0054] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A belt grinder for grinding iron tower components, characterized in that: The sanding belt (1) comprises a sanding belt (1), two rotating drums (2) and a supporting structure located inside the sanding belt (1); the sanding belt (1) is sleeved on the two rotating drums (2) and is synchronously driven; the sanding belt (1) is horizontal; and the supporting structure is used to support the upper part of the sanding belt (1) so that the upper surface of the sanding belt (1) forms a grinding plane; The conveying structure comprises two side plates (3) distributed front and back and a plurality of supporting plates (5) between the two side plates (3); the length direction of the side plates (3) is horizontal; a capsule-shaped guide groove (4) is provided on the side wall of the side plates (3); the plurality of supporting plates (5) are distributed in a capsule shape in the horizontal direction; a connecting plate (6) is fixed at both ends of each supporting plate (5); two first sliding columns (7) are fixed on the connecting plate (6); a connecting line of the two first sliding columns (7) is parallel to the surface of the supporting plate (5); and the first sliding column (7) is slidably installed in the capsule-shaped guide groove (4); When the plurality of support plates (5) move along the trajectory of the capsule-shaped guide groove (4), the plurality of support plates (5) on the upper side of the side plate (3) form a complete plane, and the complete plane lifts the upper part of the abrasive belt (1), and the vertical cross-section shape of the support plate (5) along its width direction is Z-shaped; Two adjacent connecting plates (6) in the conveying structure are connected via a spring (8); A power wheel (9) is rotatably arranged on the side plate (3), a plurality of levers (10) are arranged on the circumferential outer wall of the power wheel (9), one end of the lever (10) is inserted into the power wheel (9) by sliding along the radial direction of the power wheel (9), a slot is arranged at the other end of the lever (10), and the lever (10) is connected to the power wheel (9) via a spring sheet (11); A shifting post (27) is provided on the side wall of each connecting plate (6), and the shifting post (27) cooperates with a slot on the shifting rod (10) for use; An outer box body (12) is arranged outside the sanding belt (1), a processing opening is opened at the top of the outer box body (12), a filling column (13) is fixed in the middle of the rotating drum (2), a support shaft (14) is fixedly inserted in the middle of the filling column (13), the support shaft (14) is rotatably mounted on the inner wall of the outer box body (12), a main motor (15) for providing power to the support shaft (14) is arranged on the outer wall of the outer box body (12), and the side plate (3) and the outer box body (12) are fixedly connected via a fixing plate (16).

2. A belt grinder for grinding iron tower components according to claim 1, characterized in that: Two pressure rollers (17) are rotatably arranged in the outer box body (12), and the two pressure rollers (17) are in contact with the plane on the upper side of the sanding belt (1).

3. A belt grinder for grinding iron tower components according to claim 2, characterized in that: A plurality of retaining columns (18) are arranged on the front and rear outer walls of the rotating drum (2) outside the sanding belt (1), and a retaining groove (19) for retaining the edge of the sanding belt (1) is provided on the circumferential outer wall of the retaining column (18).

4. A belt grinder for grinding iron tower components according to claim 3, characterized in that: Each of the blocking columns (18) is provided with a sliding block (20), and the sliding block (20) is slidably mounted on the circumferential outer wall of the rotating drum (2) along the axial direction of the rotating drum (2).

5. The belt grinder for grinding an iron tower assembly according to claim 4, characterized in that: Both ends of the rotating drum (2) are provided with a fixing ring (23), which is separated from the rotating drum (2). The fixing ring (23) is fixed on the inner wall of the outer box body (12), and an annular groove is provided on the inner wall of the fixing ring (23), which is composed of a first arc groove (24), a second arc groove (25) and two transition grooves (26). A second sliding column (22) is slidably provided in the annular groove, and the second sliding column (22) is connected to the slider (20) through a connecting rod (21). When the second sliding column (22) slides in the first arc groove (24), the blocking column (18) approaches the sanding belt (1), and when the second sliding column (22) slides in the second arc groove (25), the blocking column (18) is separated from the sanding belt (1).

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