Rubber wood grinding machine

Abstract

The invention relates to the field of wood grinding, in particular to a rubber wood grinding machine. According to an existing grinding device, when wood is clamped, displacement is prone to occurring in the machining process, clamping is not stable enough, the grinding effect is reduced, pretreatment on the surface of the wood before grinding is inconvenient, the grinding effect of the wood is affected, and conveying of the wood is prone to being affected by dirt on the surface of the wood. A rubber wood grinding machine comprises four supporting legs and the like. The device comprises four supporting legs, a bottom plate is fixedly connected among the four supporting legs, a plurality of rolling rods are rotatably connected to the middle of the bottom plate, a driving motor is fixedly connected to the bottom plate, a conveying mechanism is arranged on the bottom plate, the conveying mechanism is connected with the driving motor, and the conveying mechanism is used for conveying rubber wood. After the two clamping wheels clamp a plate, the electromagnetic valve is closed, so that the water storage cylinder and the buffering cylinder are not communicated any more, water flow does not flow any more, and therefore the distance between the two clamping wheels is kept unchanged, and clamping is more stable.

Description

Technical Field

[0001] The present invention relates to the field of wood grinding, and particularly to a rubber wood grinding machine. Background Art

[0002] Rubber wood is a very commonly used furniture raw material. It is a hardwood with a moderate density and is easy to process. In order to improve the aesthetics and the roughness and unevenness of the raw material surface, the rubber wood is usually ground so that the wood surface is smoother and flatter.

[0003] However, when the existing grinding devices clamp the wood, displacement is likely to occur during processing, and the clamping is not stable enough, resulting in a reduction in the grinding effect. It is not convenient to pre-treat the wood surface before grinding, which affects the grinding effect of the wood, and it is easy to affect the conveying of the wood due to the dirt on the wood surface. Summary of the Invention

[0004] In order to overcome the disadvantages in the background art, the present invention provides a rubber wood grinding machine with stable clamping, which is not easy to displace the wood, is more convenient to pre-treat the wood before grinding, and is not easy to affect the conveying of the wood.

[0005] A rubber wood grinding machine includes four support feet. A bottom plate is fixedly connected between the four support feet. A plurality of rolling rods are rotatably connected to the middle of the bottom plate. A driving motor is fixedly connected to the bottom plate. A conveying mechanism is arranged on the bottom plate. The conveying mechanism is connected to the driving motor. The conveying mechanism is used for conveying rubber wood. A clamping mechanism is arranged on the bottom plate. The clamping mechanism is used for clamping and limiting both sides of the wood.

[0006] Optionally, the conveying mechanism includes brackets. The brackets are fixedly connected to the bottom plate. An electric grinding knife is slidably connected to the brackets. A limiting spring is connected between the electric grinding knife and the brackets. Four support plates are fixedly connected to the bottom plate. Two of the support plates form a group. A driving rubber wheel is rotatably connected between the two support plates in one group. A driven rubber wheel is rotatably connected between the two support plates in the other group. A transmission component is connected between the driven rubber wheel and the driving rubber wheel.

[0007] Optionally, the clamping mechanism includes a number of vertical blocks. A wheel frame is slidably connected to each vertical block. A connecting long rod is fixedly connected between the wheel frames on the same side. Vertical plates are fixedly connected to both sides of the bottom plate. A moving frame is slidably connected to each of the two vertical plates. A return spring is connected between the moving frame and the vertical plate. Clamping wheels are rotatably connected to the ends of the two moving frames that are close to each other. Buffer cylinders are fixedly connected to both sides of the bottom plate. A water storage cylinder is fixedly connected to the upper part of each buffer cylinder. Each water storage cylinder is provided with a sealing cover. A piston connecting rod is slidably connected in each buffer cylinder. One end of the piston connecting rod is connected to the moving frame. A balance slider is slidably connected inside each water storage cylinder. A connecting short pipe is connected between the water storage cylinder and the buffer cylinder. The connecting short pipe is in internal communication with the water storage cylinder and the buffer cylinder. An electromagnetic valve is arranged on the connecting short pipe. A speed sensor is fixedly connected to the side of each moving frame close to the clamping wheel. The speed sensor is used to control the closing of the electromagnetic valve. A guiding inclined plate is fixedly connected to one side of each moving frame. A reset button is arranged on the bottom plate. The reset button is used to control the reset of the electromagnetic valve.

[0008] Optionally, a cleaning mechanism is further included. The cleaning mechanism is arranged on the bottom plate. The cleaning mechanism is connected to the electric knife sharpener and is used for pre-treating the surface of the wood. The cleaning mechanism includes two wave groove rings. Wave grooves are formed on the wave groove rings. The two wave groove rings are fixedly connected to the rotating shaft of the active rubber wheel. A connecting frame is fixedly connected to the side of the bracket close to the active rubber wheel. Two sleeve rings are fixedly connected to the connecting frame. Protrusions are arranged on the inner walls of the sleeve rings. The two sleeve rings are respectively sleeved on the two wave groove rings. The protrusions on the inner walls of the sleeve rings are located in the wave grooves on the wave groove rings. A supporting bent frame is fixedly connected to the side of the electric knife sharpener away from the connecting frame. A swinging curved rod is rotatably connected to the middle of the supporting bent frame. An active curved rod is fixedly connected to the upper part of the swinging curved rod. A sleeve rod is fixedly connected to the side of the electric knife sharpener away from the active rubber wheel. The active curved rod passes through the sleeve rod. A cross bar is fixedly connected to the bottom plate. A sliding frame is slidably connected to the cross bar. A blunt scraper is slidably connected to the lower part of the sliding frame. A supporting spring is connected between the blunt scraper and the sliding frame. A limiting plate is fixedly connected to the sliding frame. A straight groove is formed on the limiting plate. The lower part of the swinging curved rod is located in the straight groove on the limiting plate.

[0009] Optionally, it further includes an anti-sticking mechanism. The anti-sticking mechanism is arranged on the cross bar. The anti-sticking mechanism is used to clean the surface of the driven rubber wheel. The anti-sticking mechanism includes a supporting bent rod. The supporting bent rod is fixedly connected to the cross bar. A brush disc is rotatably connected to the middle of the supporting bent rod. The brush disc contacts the surface of the driven rubber wheel. A gear is fixedly connected to the upper part of the brush disc. An arc-shaped rack is fixedly connected to the swinging curved rod. The arc-shaped rack meshes with the gear.

[0010] The beneficial effects of the present invention are as follows: 1. When the plate contacts the two clamping wheels and continues to move horizontally, the horizontal movement of the plate will drive the clamping wheels to rotate. At this time, the speed sensor is triggered. After the speed sensor is triggered, it will control the solenoid valve to close. After the solenoid valve is closed, the inside of the water storage cylinder and the inside of the buffer cylinder are no longer interconnected, so the piston connecting rod and the balance slider remain stationary, that is, the moving frame remains stationary, and the distance between the two clamping wheels remains unchanged. In this way, after the clamping wheels limit the position of the plate, it is not easy to displace due to subsequent grinding processing, improving the accuracy of grinding.

[0011] 2. When the driving rubber wheel rotates, the driving rubber wheel will drive the wave groove ring to rotate together. Then the rotation of the wave groove ring will drive the collar and the connecting frame to move horizontally back and forth together. The connecting frame will drive the electric grinding knife to move back and forth together, thereby making the grinding effect better and more uniform. The horizontal reciprocating movement of the electric grinding knife will drive the sleeve rod to move together. Then the horizontal reciprocating movement of the sleeve rod will drive the driving curved rod and the swinging curved rod to swing back and forth together. The swinging of the swinging curved rod will drive the limiting plate and the sliding frame to move horizontally back and forth together. The sliding frame will drive the blunt scraper to move horizontally back and forth together. The horizontal movement of the blunt scraper will clean the surface of the lower plate, scraping off the attachments and dirt on the plate surface to avoid affecting the grinding effect.

[0012] 3. When the swinging curved rod swings back and forth, the swinging curved rod will drive the arc-shaped rack to swing back and forth together. The reciprocating swing of the arc-shaped rack will drive the gear and the brush disc to rotate back and forth. The continuous rotation of the brush disc can clean the surface of the driven rubber wheel, making it not easy for the driven rubber wheel to slip due to the attachment of dirt on the plate, and not easy to cause the plate to be over-ground. Description of the Drawings

[0013] Figure 1 is a three-dimensional structural schematic diagram of the present invention.

[0014] Figure 2 is a three-dimensional structural schematic diagram of the conveying mechanism of the present invention.

[0015] Figure 3 is a three-dimensional structural schematic diagram of the clamping mechanism of the present invention.

[0016] Figure 4 is a three-dimensional structural schematic diagram of a part of the clamping mechanism of the present invention.

[0017] Figure 5 This is a schematic three-dimensional separation structure diagram of the buffer cylinder and the water storage cylinder of the present invention.

[0018] Figure 6 This is a schematic cross-sectional three-dimensional structure diagram of the buffer cylinder and the water storage cylinder of the present invention.

[0019] Figure 7 This is a schematic three-dimensional structure diagram of the cleaning mechanism of the present invention.

[0020] Figure 8 For the present invention Figure 7 An enlarged three-dimensional structure diagram of part A in the present invention.

[0021] Figure 9 This is a schematic three-dimensional separation structure diagram of the wave trough ring and the collar of the present invention.

[0022] Figure 10 This is a schematic three-dimensional structure diagram of the anti-sticking mechanism of the present invention.

[0023] Reference numerals in the drawings: 1: support feet, 21: bottom plate, 22: roller, 3: drive motor, 41: bracket, 42: electric knife grinder, 43: limit spring, 44: support plate, 45: active rubber wheel, 46: driven rubber wheel, 47: transmission assembly, 51: vertical block, 52: wheel frame, 53: connecting long rod, 54: vertical plate, 55: moving frame, 56: return spring, 57: clamping wheel, 58: buffer cylinder, 59: water storage cylinder, 590: sealing cover, 510: piston connecting rod, 511: balance slider, 512: connecting short pipe, 513: solenoid valve, 514: speed sensor, 515: guiding inclined plate, 516: reset button, 61: wave trough ring, 62: connecting frame, 63: collar, 64: supporting bent frame, 65: swinging curved rod, 66: active curved rod, 67: sleeve rod, 68: cross bar, 69: sliding frame, 610: blunt scraper, 611: support spring, 612: limit plate, 71: supporting bent rod, 72: brush disc, 73: gear, 74: arc rack. Detailed implementation manners

[0024] The following describes the implementation manners of the present invention with reference to the accompanying drawings.

[0025] Example 1

[0026] A rubber wood grinding machine, as Figures 1-10As shown in the figure, it includes four support feet 1. A bottom plate 21 is fixedly connected between the four support feet 1. A number of rollers 22 are rotatably connected to the middle of the bottom plate 21. A driving motor 3 is fixedly connected to the bottom plate 21. A conveying mechanism is arranged on the bottom plate 21. The conveying mechanism is connected to the driving motor 3. The conveying mechanism is used for conveying rubber wood. A clamping mechanism is arranged on the bottom plate 21. The clamping mechanism is used for clamping and limiting both sides of the wood.

[0027] The conveying mechanism includes a bracket 41. The brackets 41 are fixedly connected to the bottom plate 21. An electric knife grinder 42 is slidably connected to the bracket 41. A limiting spring 43 is connected between the electric knife grinder 42 and the bracket 41. Four support plates 44 are fixedly connected to the bottom plate 21. Two of the support plates 44 form a group. A driving rubber wheel 45 is rotatably connected between the two support plates 44 in one group. A driven rubber wheel is rotatably connected between the two support plates 44 in the other group. A transmission component 47 is connected between the driven rubber wheel 46 and the driving rubber wheel 45.

[0028] The clamping mechanism includes a number of vertical blocks 51. A wheel frame 52 is slidably connected to each vertical block 51. A connecting long rod 53 is fixedly connected between the wheel frames 52 on the same side. Vertical plates 54 are fixedly connected to both sides of the bottom plate 21. A moving frame 55 is slidably connected to each of the two vertical plates 54. A return spring 56 is connected between the moving frame 55 and the vertical plate 54. Clamping wheels 57 are rotatably connected to one end of the two moving frames 55 close to each other. Buffer cylinders 58 are fixedly connected to both sides of the bottom plate 21. A water storage cylinder 59 is fixedly connected to the upper part of each buffer cylinder 58. Each water storage cylinder 59 is provided with a sealing cover 590. A piston connecting rod 510 is slidably connected to each buffer cylinder 58. One end of the piston connecting rod 510 is connected to the moving frame 55. A balance slider 511 is slidably connected to the inside of each water storage cylinder 59. A connecting short pipe 512 is connected between the water storage cylinder 59 and the buffer cylinder 58. The connecting short pipe 512 is communicated with the inside of the water storage cylinder 59 and the buffer cylinder 58. An electromagnetic valve 513 is arranged on the connecting short pipe 512. A speed sensor 514 is fixedly connected to one side of each moving frame 55 close to the clamping wheel 57. The speed sensor 514 is used to control the closing of the electromagnetic valve 513. A guiding inclined plate 515 is fixedly connected to one side of each moving frame 55. A reset button 516 is arranged on the bottom plate 21. The reset button 516 is used to control the reset of the electromagnetic valve 513.

[0029] In actual work, the rubber wood board is a rectangular wooden board, and the surface of the board needs to be further ground to make its surface smoother. Initially, the operator adds water to the water storage tank 59 through the sealing cover 590, so that the water fills the space communicated between the buffer cylinder 58, the water storage tank 59 and the connecting short pipe 512. During the grinding process, the operator first starts the driving motor 3 and the electric grinding knife 42. The driving motor 3 drives the active rubber wheel 45 to rotate, and the active rubber wheel 45 drives the driven rubber wheel 46 to rotate together through the transmission assembly 47. Then, the board is horizontally placed from one side of the guiding inclined plate 515, and the board is squeezed to make the two guiding inclined plates 515 move horizontally away from each other. The horizontal movement of the guiding inclined plate 515 drives the two clamping wheels 57 and the moving frame 55 to move horizontally away from each other. Then the operator continues to horizontally place the board. The two clamping wheels 57 contact both sides of the board. After the rotating active rubber wheel 45 contacts the upper surface of the board, the active rubber wheel 45 drives the board to continue to move horizontally in the direction of the electric grinding knife 42 through friction and the board is ground. When the board squeezes the two guiding inclined plates 515 and drives the two clamping wheels 57 and the moving frame 55 to move horizontally away from each other, at this time the electromagnetic valve 513 is in the open state, the return spring 56 is compressed, and the horizontal movement of the moving frame 55 drives the piston connecting rod 510 to move horizontally together. The horizontal movement of the two piston connecting rods 510 in the direction away from each other squeezes the water inside the buffer cylinder 58 into the water storage tank 59, and the two balance sliders 511 are pushed by the water to move horizontally towards each other. When the board contacts the two clamping wheels 57 and continues to move horizontally, the horizontal movement of the board drives the clamping wheels 57 to rotate. At this time, the speed sensor 514 is triggered, and the triggering of the speed sensor 514 controls the electromagnetic valve 513 to close. After the electromagnetic valve 513 closes, the inside of the water storage tank 59 and the inside of the buffer cylinder 58 are no longer communicated. Due to the incompressibility of the liquid, the piston connecting rod 510 and the balance slider 511 remain stationary, that is, the moving frame 55 remains stationary, and the distance between the two clamping wheels 57 remains unchanged. In this way, after the clamping wheels 57 limit the position of the board, it is not easy to displace due to subsequent grinding processing, improving the accuracy of grinding. When the board is ground, the ground part of it contacts the active rubber wheel 45, and the active rubber wheel 45 continues to drive the board to move horizontally until the entire upper surface of the board is ground. After the board is ground, the operator turns off the driving motor 3 and the electric grinding knife 42, and presses the reset button 516. After the reset button 516 is pressed, it controls the electromagnetic valve 513 to open, and the inside of the water storage tank 59 and the inside of the buffer cylinder 58 are communicated again. Then the return spring 56 drives the moving frame 55 and the piston connecting rod 510 to move back to the original position.

[0030] Embodiment 2

[0031] On the basis of Embodiment 1, as Figures 7-10As shown in the figure, it further includes a cleaning mechanism. The cleaning mechanism is arranged on the bottom plate 21 and is connected to the electric knife sharpener 42. The cleaning mechanism is used for pre-treating the surface of the wood. The cleaning mechanism includes two wave groove rings 61. Wave grooves are formed on the wave groove rings 61. Both of the two wave groove rings 61 are fixedly connected to the rotating shaft of the driving rubber wheel 45. A connecting frame 62 is fixedly connected to one side of the support 41 close to the driving rubber wheel 45. Two collar rings 63 are fixedly connected to the connecting frame 62. Protrusions are arranged on the inner walls of the collar rings 63. The two collar rings 63 are respectively sleeved on the two wave groove rings 61. The protrusions on the inner walls of the collar rings 63 are located in the wave grooves on the wave groove rings 61. A support bent frame 64 is fixedly connected to one side of the electric knife sharpener 42 away from the connecting frame 62. A swing curved rod 65 is rotatably connected to the middle of the support bent frame 64. An active curved rod 66 is fixedly connected to the upper part of the swing curved rod 65. A sleeve rod 67 is fixedly connected to one side of the electric knife sharpener 42 away from the driving rubber wheel 45. The active curved rod 66 passes through the sleeve rod 67. A cross bar 68 is fixedly connected to the bottom plate 21. A sliding frame 69 is slidably connected to the cross bar 68. A blunt scraper 610 is slidably connected to the lower part of the sliding frame 69. A support spring 611 is connected between the blunt scraper 610 and the sliding frame 69. A limiting plate 612 is fixedly connected to the sliding frame 69. A straight groove is formed on the limiting plate 612. The lower part of the swing curved rod 65 is located in the straight groove on the limiting plate 612.

[0032] It further includes an anti-sticking mechanism. The anti-sticking mechanism is arranged on the cross bar 68 and is used for cleaning the surface of the driven rubber wheel 46. The anti-sticking mechanism includes a support bent rod 71. The support bent rod 71 is fixedly connected to the cross bar 68. A brush disc 72 is rotatably connected to the middle of the support bent rod 71. The brush disc 72 is in contact with the surface of the driven rubber wheel 46. A gear 73 is fixedly connected to the upper part of the brush disc 72. An arc-shaped rack 74 is fixedly connected to the swing curved rod 65. The arc-shaped rack 74 is engaged with the gear 73.

[0033] When the driving rubber wheel 45 rotates, the driving rubber wheel 45 will drive the wave groove ring 61 to rotate together. Then, the rotation of the wave groove ring 61 will drive the collar 63 and the connecting frame 62 to reciprocate horizontally. The connecting frame 62 will drive the electric knife grinder 42 to reciprocate, thereby making the grinding effect better and more uniform. The horizontal reciprocating movement of the electric knife grinder 42 will drive the sleeve rod 67 to move together. Then, the horizontal reciprocating movement of the sleeve rod 67 will drive the driving curved rod 66 and the swinging curved rod 65 to swing reciprocally. The swinging of the swinging curved rod 65 will drive the limit plate 612 and the sliding frame 69 to reciprocate horizontally. The sliding frame 69 will drive the blunt scraper 610 to reciprocate horizontally. The horizontal movement of the blunt scraper 610 will clean the surface of the lower plate, scraping off the attachments and dirt on the plate surface to avoid affecting the grinding effect.

[0034] When the swinging curved rod 65 swings reciprocally, the swinging curved rod 65 will drive the arc-shaped rack 74 to swing reciprocally. The reciprocal swinging of the arc-shaped rack 74 will drive the gear 73 and the brush disc 72 to rotate reciprocally. The continuous rotation of the brush disc 72 can clean the surface of the driven rubber wheel 46, making it not easy for the driven rubber wheel 46 to slip due to the attachment of dirt on the plate, and not easy for the plate to be over-ground.

[0035] The above are only examples of the present invention and are not used to limit the present invention. All equivalent substitutions made within the principle of the present invention shall be included in the protection scope of the present invention. The content not elaborated in detail in the present invention belongs to the known prior art of those skilled in the art.

Claims

1. A rubber wood grinding machine, characterized in that: The invention comprises four supporting legs (1), a bottom plate (21) being fixedly connected between the four supporting legs (1), a plurality of rollers (22) being rotatably connected to the middle of the bottom plate (21), a driving motor (3) being fixedly connected to the bottom plate (21), a conveying mechanism being arranged on the bottom plate (21), the conveying mechanism being connected to the driving motor (3), the conveying mechanism being used for conveying rubber wood, and a clamping mechanism being arranged on the bottom plate (21), the clamping mechanism being used for clamping and limiting the positions of two sides of the wood.

2. A rubber wood grinding machine according to claim 1, characterized in that: The conveying mechanism comprises a bracket (41), the brackets (41) are fixedly connected to the bottom plate (21), an electric sharpener (42) is slidably connected to the bracket (41), a limit spring (43) is connected between the electric sharpener (42) and the bracket (41), four support plates (44) are fixedly connected to the bottom plate (21), two support plates (44) form a group, a driving rubber wheel (45) is rotatably connected between the two support plates (44) of one group, a driven rubber wheel (45) is rotatably connected between the two support plates (44) of the other group, and a transmission assembly (47) is connected between the driven rubber wheel (46) and the driving rubber wheel (45).

3. A rubber wood grinding machine according to claim 2, characterized in that: The clamping mechanism comprises a plurality of vertical blocks (51), each of the vertical blocks (51) is slidably connected to a wheel frame (52), a connecting long rod (53) is fixedly connected between the wheel frames (52) on the same side, both sides of the bottom plate (21) are fixedly connected to vertical plates (54), both vertical plates (54) are slidably connected to a moving frame (55), a return spring (56) is connected between the moving frame (55) and the vertical plates (54), and one end of the two moving frames (55) close to each other is rotatably connected to a clamping wheel (57), both sides of the bottom plate (21) are fixedly connected to a buffer cylinder (58), the upper part of each buffer cylinder (58) is fixedly connected to a water storage cylinder (59), each water storage cylinder (59) is provided with a sealing cover (590), each buffer cylinder (58) is slidably connected to a piston connecting rod (510), and the piston connecting rod (510) is One end of the movable frame (510) is connected to the movable frame (55), and a balancing slider (511) is slidably connected inside each of the water storage cylinders (59). A connecting short pipe (512) is connected between the water storage cylinder (59) and the buffer cylinder (58), and the connecting short pipe (512) is communicated with the inside of the water storage cylinder (59) and the buffer cylinder (58). A solenoid valve (513) is arranged on the connecting short pipe (512). A speed sensor (514) is fixedly connected to one side of each of the movable frames (55) close to the clamping wheel (57), and the speed sensor (514) is used to control the solenoid valve (513) to close. A guide inclined plate (515) is fixedly connected to one side of each of the movable frames (55), and a reset button (516) is arranged on the bottom plate (21), and the reset button (516) is used to control the solenoid valve (513) to reset.

4. A rubber wood grinding machine according to claim 3, characterized in that: The invention also comprises a cleaning mechanism, which is arranged on the bottom plate (21) and connected to the electric sharpener (42). The cleaning mechanism is used for pre-treating the surface of the wood. The cleaning mechanism comprises two wave groove rings (61), each of which has a wave groove. The two wave groove rings (61) are fixedly connected to the rotating shaft of the active rubber wheel (45). A connecting frame (62) is fixedly connected to the side of the bracket (41) close to the active rubber wheel (45). Two sleeve rings (63) are fixedly connected to the connecting frame (62). The inner wall of the sleeve ring (63) is provided with a protrusion. The two sleeve rings (63) are respectively sleeved on the two wave groove rings (61). The protrusions on the inner wall of the sleeve ring (63) are located in the wave groove on the wave groove ring (61). The electric sharpener (42) is fixedly connected to the side away from the connecting frame (62). A support bent frame (64) is provided, a swinging crank rod (65) is rotatably connected to the middle of the support bent frame (64), an active crank rod (66) is fixedly connected to the upper part of the swinging crank rod (65), a sleeve rod (67) is fixedly connected to the side of the electric sharpener (42) away from the active rubber wheel (45), the active crank rod (66) passes through the sleeve rod (67), a cross bar (68) is fixedly connected to the bottom plate (21), and the cross bar ( A sliding frame (69) is slidably connected to the upper portion of the sliding frame (68); a blunt scraper (610) is slidably connected to the lower portion of the sliding frame (69); a supporting spring (611) is connected between the blunt scraper (610) and the sliding frame (69); a limiting plate (612) is fixedly connected to the sliding frame (69); a straight groove is formed on the limiting plate (612); and the lower portion of the swinging curved rod (65) is located in the straight groove on the limiting plate (612).

5. A rubber wood grinding machine according to claim 4, characterized in that: The invention also comprises an anti-sticking mechanism, which is arranged on the cross bar (68) and is used for cleaning the surface of the driven rubber wheel (46). The anti-sticking mechanism comprises a supporting curved rod (71), which is fixedly connected to the cross bar (68). A brush disc (72) is rotatably connected to the middle of the supporting curved rod (71), and the brush disc (72) contacts the surface of the driven rubber wheel (46). A gear (73) is fixedly connected to the upper part of the brush disc (72). An arc-shaped rack (74) is fixedly connected to the swinging curved rod (65), and the arc-shaped rack (74) is meshed with the gear (73).

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