Curved surface polishing device for special-shaped ventilation duct

Abstract

The application discloses a special-shaped ventilation pipeline curved surface polishing device, and belongs to the technical field of ventilation pipeline polishing.The special-shaped ventilation pipeline curved surface polishing device comprises a rack, two mounting racks which are oppositely arranged are fixed on the rack, rotating rods are rotatably installed on the two mounting racks, a servo motor is installed on the rack, and a transmission part is arranged between the servo motor and one of the rotating rods.The inner supporting type clamping structure is adopted to support and fix the ventilation pipeline from the inside of the two end ports of the ventilation pipeline.After the clamping structure is connected with the overturning assembly, the ventilation pipeline is wholly erected on the rack, the ventilation pipeline is overturned by the servo motor driving the overturning assembly, each spliced area and the curved surface are sequentially turned to positions facing the operator, and the operator can complete polishing of all curved surfaces at the fixed station, and it is unnecessary to repeatedly walk around the ventilation pipeline and manually overturn or move the ventilation pipeline.

Description

Technical Field

[0001] This invention relates to the field of ventilation duct polishing technology, specifically a device for polishing the curved surface of irregularly shaped ventilation ducts. Background Technology

[0002] The ventilation duct curved surface polishing device is a special equipment used for automatic grinding and polishing of the outer wall of ventilation ducts.

[0003] 90° galvanized steel plate shrimp-shaped ventilation duct is one of the most common types of ventilation ducts in HVAC, dust removal and exhaust systems and industrial ventilation systems. This type of ventilation duct is made of multiple sections of galvanized steel plates spliced ​​and welded together. The surface has defects such as weld seams, weld scars, welding spatter, undercut burrs and local burn damage to the galvanized layer. Therefore, it is necessary to polish its curved surface during the production process. In existing technologies, the common practice is for workers to use angle grinders with grinding wheels or polishing discs to grind and level weld spatter and spatter. After finishing, the curved surfaces are polished to give the ventilation duct a high gloss. Because these ventilation ducts are large, during the actual polishing process, operators need to constantly adjust their position and posture around the outside of the ventilation duct to adapt to the grinding angle of different curved surfaces. At the same time, it is necessary to manually flip or move the ventilation duct to cover each splicing area and curved surface. However, the curved transition and multi-section splicing structure of the ventilation duct itself make the flipping operation lack stable clamping and support points. The repeated flipping and positioning during the operation takes up a lot of auxiliary time, resulting in difficult operation and low efficiency.

[0004] Therefore, the present invention provides a device for polishing the curved surface of irregular ventilation ducts to solve the above-mentioned problems. Summary of the Invention

[0005] This invention provides a device for polishing curved surfaces of irregularly shaped ventilation ducts, aiming to solve the problems of existing technologies where polishing of curved surfaces of large, multi-section ventilation ducts relies on manual rotation and adjustment of the stand, lacks stable support, and is difficult, time-consuming, and inefficient.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a surface polishing device for irregularly shaped ventilation ducts, comprising a frame, on which two mounting brackets are fixedly arranged opposite each other, and rotating rods are rotatably mounted on each of the two mounting brackets. The two rotating rods are coaxially arranged, and a servo motor is mounted on the frame. A transmission component is provided between the servo motor and one of the rotating rods, and the transmission component adopts a belt drive transmission method. A flipping assembly is provided between the two mounting brackets. The two sides of the flipping assembly are respectively connected to the two rotating rods and are driven by the rotating rods to rotate around the common axis of the two rotating rods. The flipping assembly includes a support plate, a connecting plate, and two sliding structures. The support plate and the connecting plate are fixedly connected. The support plate and the connecting plate together form a frame structure. Each sliding structure includes a guide rail and a slide block. The guide rail is fixed to the support plate. The length directions of the guide rails of the two sliding structures are perpendicular to each other and correspond to the ports at both ends of the irregular ventilation duct. The slide block is slidably mounted on the corresponding guide rail. A fixing block is fixed on the top surface of the slide block, and a fixing plate is fixed on the fixing block. A plurality of first threaded slots are opened on the guide rail, and a positioning port is opened on the slide block. The flipping component is provided with a clamping component, which includes two clamping structures. The two clamping structures are respectively connected to the two fixed plates. Each clamping structure includes a clamping part, a driving part, and a locking part. The clamping part includes a frame, multiple sliders, and multiple pressure blocks. The frame is provided with multiple sliding grooves, and the multiple sliders are slidably disposed in the sliding grooves one by one. The driving part is arranged on the side of the frame and is used to drive the multiple pressure blocks to move closer or further away from each other synchronously, so as to support the pipe wall from the inside of the two ends of the irregular ventilation duct; the locking part is used to lock the driving part to fix the position of the multiple pressure blocks.

[0007] Preferably, the drive unit includes a rotating shaft, a turntable, and four connecting arms. The rotating shaft is rotatably mounted on the side of the frame, the turntable is fixedly sleeved on the rotating shaft, one end of each of the four connecting arms is hinged to the turntable, and the other end of each of the four connecting arms is respectively hinged to one of the four sliders. When the rotating shaft rotates, it drives the turntable to rotate, and the corresponding sliders are driven to move synchronously radially along the slide groove via the four connecting arms.

[0008] Preferably, the four sliders are arranged in a circumferential array around the axis of the rotating shaft, and each slider has a mounting plate fixed to its side. The end of the mounting plate away from the corresponding slider is fixed with the pressure block. Each pressure block has a soft pad on its side, which is used to fit against the inner wall of the irregular ventilation duct.

[0009] Preferably, the locking part includes a gear, a side plate, a lead screw, and a toothed plate. The gear is fixedly sleeved on the rotating shaft, the side plate is fixed to the side of the frame, the lead screw is threaded to the side plate, and the bottom end of the lead screw is rotatably connected to the toothed plate. The bottom surface of the toothed plate is provided with teeth that are adapted to the gear. When the teeth mesh with the gear, the toothed plate locks the gear, the rotating shaft, and the turntable. When the toothed plate is separated from the gear, the rotating shaft can rotate freely.

[0010] Preferably, the locking part further includes a guide block and a guide plate. The guide block is fixed to the side of the toothed plate, and the guide plate is fixed to the side of the frame. A slot is provided on the side of the guide block, and the guide plate passes through the slot and is slidably connected to the slot to guide the movement of the toothed plate.

[0011] Preferably, a plurality of the first threaded slots are arranged in a linear array along the length of the guide rail, the top surface of the fixing plate is provided with a slot, and the bottom of the slot is provided with a second threaded slot.

[0012] Preferably, the support plate and the connecting plate are fixedly connected and enclosed to form an L-shaped frame structure, the support plate is connected to one of the rotating rods, and the connecting plate is connected to the other rotating rod.

[0013] Preferably, the clamping structure further includes a lifting part, which includes a lifting frame, an assembly plate, and a lifting ring. The lifting frame is fixed to the side of the frame and has a U-shaped structure. The assembly plate is fixed to the side of the lifting frame. The assembly plate is adapted to the slot and placed in the slot. The assembly plate has a through hole. A bolt passes through the through hole and is screwed into the second threaded slot to fix the assembly plate to the fixing plate. The lifting ring is fixed on the lifting frame.

[0014] 1. This invention adopts an internal support clamping structure, which supports and fixes the ventilation duct from the inside of both ends of the ventilation duct. After the clamping structure is connected to the flipping component, the ventilation duct is erected on the frame as a whole. The flipping component is driven by a servo motor to flip the ventilation duct. Each splicing area and arc surface turns to the position facing the operator in sequence. The operator can complete the grinding and polishing of all curved surfaces at the fixed work station. Non-rotating bends can also turn to the fixed work station one by one, saving the auxiliary time of manual walking, flipping and moving. 2. The distance between the two slides can be adjusted along the guide rail to accommodate irregularly shaped ventilation ducts with different bending radii and diameter specifications; 3. The internal support method applies force from inside the port, does not obstruct the outer surface of the ventilation duct, does not produce external clamping marks, the soft pad increases friction and protects the thin-walled port, and the polishing work surface is not affected by the clamping structure. 4. The four pressure blocks can be expanded synchronously and equally in diameter by hand, with high centering accuracy. After locking, the tension force does not rebound and it will not loosen under polishing vibration. Attached Figure Description

[0015] To clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings are briefly described below. The drawings are merely illustrative diagrams and not actual physical representations, and should not be construed as limiting the scope of protection of this patent. For ease of structural demonstration, some components in the drawings are omitted, enlarged, or reduced, and do not correspond to the actual dimensions of the product.

[0016] Figure 1 A schematic diagram of a surface polishing device for irregularly shaped ventilation ducts; Figure 2 This is a structural diagram of the flipping component and the clamping component; Figure 3 A structural diagram illustrating the adaptability of the flip-up assembly to ventilation ducts of different sizes; Figure 4 This is a schematic diagram of the flip component. Figure 5 A schematic diagram of the structure when the two clamping parts are respectively assembled at both ends of the ventilation duct; Figure 6 This is a structural schematic diagram of the clamping part and the driving part; Figure 7 A schematic diagram of the clamping part, locking part and hoisting part; Figure 8 Assembly drawing for the hoisting unit and the fixing plate; Figure 9 This is a schematic diagram of the structure when the flipping component and the ventilation duct are flipped.

[0017] In the diagram: 1. Frame; 2. Mounting bracket; 3. Rotating rod; 4. Servo motor; 5. Handheld polisher; 61. Support plate; 62. Connecting plate; 63. Guide rail; 64. Slide; 65. First threaded groove; 66. Positioning port; 67. Fixing block; 68. Fixing plate; 69. Slot; 610. Second threaded groove; 71. Frame; 72. Slide groove; 73. Slider; 74. Mounting plate; 75. Pressure block; 76. Soft pad; 81. Rotating shaft; 82. Turntable; 83. Connecting arm; 91. Gear; 92. Side plate; 93. Lead screw; 94. Tooth plate; 95. Guide block; 96. Guide plate; 101. Lifting bracket; 102. Assembly plate; 103. Through hole; 104. Lifting ring. Detailed Implementation

[0018] It should be understood that, referring to the technical solutions disclosed in this invention, without changing the essential inventive concept of this invention, those skilled in the art can design a variety of interchangeable component structures, assembly forms, and process implementation methods. Therefore, the specific embodiments and accompanying drawings listed in the specification are merely exemplary implementations of this invention and cannot represent all implementable situations of this invention. Nor should the specific details of the embodiments be used to narrow the protection boundary of this invention. Equivalent modifications made by those skilled in the art based on the teachings of this invention are all within the scope of this invention, and the scope of protection is determined by the claims.

[0019] This invention provides a device for polishing the curved surface of irregularly shaped ventilation ducts, such as... Figure 1 As shown, the device includes a frame 1, on which a handheld polisher 5 is mounted. The specific structure and working principle of the handheld polisher 5 are existing technologies and will not be described in detail here. The staff can use the handheld polisher 5 to polish the ventilation duct. Two mounting brackets 2 are fixed on the frame 1 and are facing each other. Rotating rods 3 are rotatably mounted on the opposite sides of the two mounting brackets 2. A servo motor 4 is mounted on the frame 1. A transmission component is provided between the servo motor 4 and one of the rotating rods 3 and is connected by the transmission component. The transmission component adopts a belt drive method. When the servo motor 4 is running, it can drive the corresponding rotating rod 3 to rotate through the transmission component. A flipping assembly is provided between the two mounting brackets 2. The flipping assembly includes a support plate 61, a connecting plate 62, and two sliding structures. The support plate 61 and the connecting plate 62 are fixedly connected. Both the support plate 61 and the connecting plate 62 have an L-shaped structure. The two sliding structures are arranged on the support plate 61. Each sliding structure includes a guide rail 63 and a slide block 64. The guide rail 63 is fixed to the support plate 61, and the slide block 64 is slidably mounted on the guide rail 63 and can slide freely along the guide rail 63. Figure 2 As shown, the two guide rails 63 are located on two mutually perpendicular parts of the support plate 61, so the two guide rails 63 are also perpendicular to each other. In addition, the two guide rails 63 are fixed to the top surface of the support plate 61.

[0020] The guide rail 63 has several first threaded slots 65, which are arranged in a linear array along the length of the guide rail 63. The slide block 64 has a positioning port 66. The operator can pass a bolt through the positioning port 66 and screw it into one of the first threaded slots 65 to fix the slide block 64 to the guide rail 63. The arrangement of several first threaded slots 65 makes it convenient for the operator to fix the slide block 64 at different positions on the guide rail 63.

[0021] A fixing block 67 is fixed on the top surface of the slide block 64. A fixing plate 68 is fixed on the side of the fixing block 67 away from the slide block 64. A slot 69 is opened on the top surface of the fixing plate 68. A second threaded slot 610 is opened at the bottom of the slot 69.

[0022] A clamping assembly is provided on the top of the frame 1. The clamping assembly includes two clamping structures, which are respectively connected to two fixed plates 68. The clamping structure includes a clamping part, a driving part, a locking part, and a lifting part.

[0023] The clamping part includes a frame 71, on which four sliding grooves 72 are provided. A slider 73 is slidably disposed in each sliding groove 72. The slider 73 and the sliding groove 72 are fitted with a clearance. A mounting plate 74 is fixed to the side of each slider 73. A pressure block 75 is fixed to the end of each mounting plate 74 away from the corresponding slider 73. A soft pad 76 is provided on the side of each pressure block 75. The soft pad 76 can increase the friction between the pressure block 75 and the ventilation duct and fit against the inner wall of the ventilation duct, thereby improving the clamping stability of the clamping part for the ventilation duct.

[0024] The drive unit includes a rotating shaft 81, a turntable 82, and four connecting arms 83. The rotating shaft 81 is rotatably mounted on the side of the frame 71. The four sliders 73 are arranged in a circumferential array around the axis of the rotating shaft 81. The turntable 82 is fixedly sleeved on the rotating shaft 81, and the axis of the turntable 82 coincides with the axis of the rotating shaft 81. One end of each of the four connecting arms 83 is hinged to the turntable 82, and the other end of each of the four connecting arms 83 is hinged to the four sliders 73 respectively. When the rotating shaft 81 rotates, it drives the turntable 82 to rotate. When the turntable 82 rotates, it controls the four sliders 73 to move synchronously through the four connecting arms 83, so that the four pressure blocks 75 move closer or further away from each other synchronously. The four grooves 72 are arranged in a circumferential array around the rotating shaft 81, forming a cross-shaped structure, so that the four pressure blocks 75 can move radially synchronously.

[0025] The locking mechanism includes a gear 91, a side plate 92, and a toothed plate 94. The gear 91 is fixedly mounted on the rotating shaft 81. The side plate 92 is fixed to the side of the frame 71. The side plate 92 is threadedly connected to a lead screw 93. The bottom end of the lead screw 93 is rotatably connected to the toothed plate 94. The bottom surface of the toothed plate 94 is provided with teeth that are compatible with the gear 91, and the teeth of the toothed plate 94 mesh with the gear 91. When the toothed plate 94 meshes with the gear 91, the toothed plate 94 provides a locking effect on the gear 91. At this time, the gear 91, the rotating shaft 81, and the turntable 82 cannot rotate, and the four pressure blocks 75 cannot move. When the toothed plate 94 is separated from the gear 91, the gear 91, the rotating shaft 81, and the turntable 82 can rotate freely. At this time, the operator can adjust the position of the four pressure blocks 75.

[0026] The locking part also includes a guide block 95 and a guide plate 96. The guide block 95 is fixed to the side of the toothed plate 94, and the guide plate 96 is fixed to the side of the frame 71. A slot is provided on the side of the guide block 95. The guide plate 96 passes through the slot and is slidably connected to the slot. The guide block 95 and the guide plate 96 together provide a limit for the toothed plate 94, so that the toothed plate 94 cannot rotate with the lead screw 93, and thus the toothed plate 94 moves linearly under the rotation of the lead screw 93.

[0027] The hoisting unit includes a hoisting frame 101, an assembly plate 102, and a lifting ring 104. The hoisting frame 101 is fixed to the side of the frame 71 and has a U-shaped structure. The assembly plate 102 is fixed to the side of the hoisting frame 101, and its dimensions are compatible with the dimensions of the slot 69. The assembly plate 102 has a through-hole 103. The lifting ring 104 is fixed to the hoisting frame 101. Figure 8 As shown, when the assembly plate 102 is placed into the slot 69, the operator can pass the bolt through the through hole 103 and screw it into the second threaded slot 610 to fix the assembly plate 102 and the fixing plate 68 together.

[0028] The working principle of this invention is as follows: First, the workers install the two clamping structures at both ends of the ventilation duct. Before installation, the screw 93 is rotated so that the toothed plate 94 moves linearly under the limiting action of the guide block 95 and the guide plate 96 and separates from the gear 91. At this time, the drive shaft 81 and the turntable 82 are in a state of free rotation. Then, the clamping structure is inserted into the port of the ventilation duct and the drive shaft 81 is rotated. The shaft 81 drives the turntable 82 to rotate. The turntable 82 is driven by four connecting arms 83 that are respectively hinged to the turntable 82 and the slider 73. The four sliders 73 move radially synchronously along the slide groove 72 on the frame 71. The four sliders 73 are then driven by the mounting plates 74 fixed on their respective sides to move the four pressure blocks 75 away from each other synchronously until the soft pads 76 on the side of the pressure blocks 75 are attached to the inner wall of the ventilation duct and tighten the duct wall.

[0029] Then, the screw 93 is rotated in the opposite direction, pushing the toothed plate 94 to move linearly, so that its bottom teeth mesh with the gear 91 fixedly sleeved on the rotating shaft 81, locking the gear 91, rotating shaft 81 and turntable 82. The positions of the four pressure blocks 75 are fixed and kept in a supported state. In the same way, another clamping structure is installed at the other end of the ventilation duct. The two clamping structures support the ventilation duct from the inside, forming a... Figure 5 As shown, the soft pad 76 increases the friction between the pressure block 75 and the inner wall and fits against the inner wall, so that both ends of the ventilation duct are stably clamped and supported.

[0030] Subsequently, based on the dimensions of the ventilation duct, the staff slid the two slide blocks 64 along their corresponding guide rails 63 to adjust the spacing to correspond to the positions of the two clamping structures. Then, bolts were passed through the positioning holes 66 on the slide blocks 64 and screwed into the aligned first threaded slots 65, fixing the two slide blocks 64 to their respective positions on the guide rails 63. The fixing plate 68 connected to the top surface of the slide blocks 64 via the fixing block 67, and the slot 69 on the fixing plate 68, were then positioned to connect with the clamping structures. Figure 3 As shown, the adjustable arrangement of the two slides 64 allows the flip assembly to be adapted to ventilation ducts of different sizes, improving the versatility of the invention.

[0031] Furthermore, the workers hook the lifting equipment, such as the electric hoist, onto the two lifting rings 104. The lifting rings 104 support the ventilation duct with clamping structures installed at both ends and lift it as a whole. After being lifted above the two slides 64, it is lowered into position so that the assembly plate 102 fixed to the side of the lifting frame 101 is placed into the slot 69 on the top surface of the fixing plate 68. The size of the assembly plate 102 matches the size of the slot 69. Then, the bolts are passed through the through holes 103 on the assembly plate 102 and screwed into the second threaded slot 610 at the bottom of the slot 69 to fix the assembly plate 102 to the fixing plate 68. After the two clamping structures are fixed, the ventilation duct is installed on the two slides 64.

[0032] After hoisting, workers use a handheld polishing machine 5 to grind, level, and polish the welds, weld scars, welding spatter, and burrs on the curved surface of the ventilation duct. When it is necessary to change the working curved surface, the servo motor 4 installed on the frame 1 is started. The servo motor 4 drives the rotating rod 3 connected to it to rotate through the belt drive transmission component. The rotating rod 3 drives the flipping component between the two mounting brackets 2 to rotate. The two clamping structures rotate synchronously with the flipping component, thereby driving the ventilation duct to rotate together, so that each splicing area and curved surface turns to the position facing the workers in sequence. The workers do not need to constantly adjust their position and posture around the ventilation duct, nor do they need to manually flip or move the ventilation duct. The polishing of each curved surface of the ventilation duct can be completed in place, reducing the auxiliary time occupied by repeated flipping and positioning. It should be noted that the servo motor 4 has a self-locking function. When the servo motor 4 stops running, it can lock the corresponding rotating rod 3 in the current position, thereby locking the position of the ventilation duct. This is existing technology and will not be described in detail here.

[0033] After polishing, remove the bolts at the through 103 and lift the ventilation duct with the lifting ring 104. Then rotate the screw 93 to separate the toothed plate 94 from the gear 91. Rotate the shaft 81 of the drive unit in the opposite direction. The turntable 82 and the connecting arm 83 drive the four pressure blocks 75 to move closer to each other synchronously and the soft pad 76 to detach from the inner wall of the ventilation duct. Then the two clamping structures can be removed from both ends of the ventilation duct.

[0034] The specific embodiments described in this specification are only used to illustrate the technical solutions of the present invention and to help understand the present invention. They are not intended to limit the scope of protection of the present invention. All equivalent transformations, component modifications, and process parameter adjustments that can be easily conceived by those skilled in the art based on the technical content disclosed in the present invention specification and drawings, without changing the function to be achieved by the present invention and the corresponding technical effect, fall within the scope of protection defined by the claims of the present invention. The patent protection boundary should not be narrowed due to the specific structure of the embodiments.

Claims

1. A polishing device for curved surfaces of irregularly shaped ventilation ducts, comprising a frame (1), wherein a handheld polishing machine (5) is mounted on the frame (1), characterized in that: Two mounting brackets (2) are fixed on the frame (1). Rotating rods (3) are rotatably mounted on both mounting brackets (2). A servo motor (4) is mounted on the frame (1). A transmission component is provided between the servo motor (4) and one of the rotating rods (3). The transmission component adopts a belt drive transmission method. A flipping assembly is provided between the two mounting brackets (2). The two sides of the flipping assembly are respectively connected to the two rotating rods (3). The flipping assembly includes a support plate (61), a connecting plate (62) and a sliding structure. The two sliding structures are arranged on the top surface of the support plate (61) and are perpendicular to each other. The support plate (61) and the connecting plate (62) are fixedly connected. The support plate (61) and the connecting plate (62) together form a frame structure. The support plate (61) is connected to one of the rotating rods (3), and the connecting plate (62) is connected to the other rotating rod (3). The support plate (61) and the connecting plate (62) can be driven by a servo motor (4) to achieve synchronous rotation; The flipping component is provided with a clamping component, which includes two clamping structures. The two clamping structures are respectively connected to two sliding structures. Each clamping structure includes a clamping part, a driving part, and a locking part.

2. The irregular-shaped ventilation duct curved surface polishing device according to claim 1, characterized in that: The sliding structure includes a guide rail (63) and a slide block (64). The guide rail (63) is fixed on the support plate (61). The slide block (64) is slidably assembled on the corresponding guide rail (63). A fixing block (67) is fixed on the top surface of the slide block (64). A fixing plate (68) is fixed on the fixing block (67). A plurality of first threaded slots (65) are opened on the guide rail (63). A positioning port (66) is opened on the slide block (64).

3. The irregularly shaped ventilation duct curved surface polishing device according to claim 2, characterized in that: The clamping part includes a frame (71), multiple sliders (73) and multiple pressure blocks (75). Multiple grooves (72) are provided on the frame (71), and the multiple sliders (73) are slidably disposed in the grooves (72) in a corresponding manner.

4. The irregularly shaped ventilation duct curved surface polishing device according to claim 3, characterized in that: The drive unit includes a rotating shaft (81), a turntable (82), and four connecting arms (83). The rotating shaft (81) is rotatably mounted on the side of the frame (71). The turntable (82) is fixedly sleeved on the rotating shaft (81). One end of each of the four connecting arms (83) is hinged to the turntable (82), and the other end of each of the four connecting arms (83) is hinged to one of the four sliders (73). When the rotating shaft (81) rotates, it drives the turntable (82) to rotate, and the corresponding sliders (73) are driven to move synchronously radially along the groove (72) via the four connecting arms (83).

5. The irregularly shaped ventilation duct curved surface polishing device according to claim 4, characterized in that: The four sliders (73) are arranged in a circumferential array around the axis of the rotating shaft (81). Each slider (73) has a mounting plate (74) fixed on its side. The mounting plate (74) has a pressure block (75) fixed at one end away from the corresponding slider (73). Each pressure block (75) has a soft pad (76) on its side. The soft pad (76) is used to fit against the inner wall of the irregular ventilation duct.

6. The irregularly shaped ventilation duct curved surface polishing device according to claim 5, characterized in that: The locking part includes a gear (91), a side plate (92), a lead screw (93), and a toothed plate (94). The gear (91) is fixedly sleeved on the rotating shaft (81). The side plate (92) is fixed to the side of the frame (71). The lead screw (93) is threaded to the side plate (92). The bottom end of the lead screw (93) is rotatably connected to the toothed plate (94). The bottom surface of the toothed plate (94) is provided with teeth that are adapted to the gear (91). When the teeth mesh with the gear (91), the toothed plate (94) locks the gear (91), the rotating shaft (81), and the turntable (82). When the toothed plate (94) is separated from the gear (91), the rotating shaft (81) can rotate freely.

7. The irregularly shaped ventilation duct curved surface polishing device according to claim 6, characterized in that: The locking part also includes a guide block (95) and a guide plate (96). The guide block (95) is fixed to the side of the toothed plate (94), and the guide plate (96) is fixed to the side of the frame (71). The guide block (95) has a slot on its side. The guide plate (96) passes through the slot and is slidably connected to the slot to guide the movement of the toothed plate (94).

8. The irregularly shaped ventilation duct curved surface polishing device according to claim 7, characterized in that: A number of first threaded slots (65) are arranged in a straight array along the length of the guide rail (63), and a slot (69) is provided on the top surface of the fixing plate (68), and a second threaded slot (610) is provided at the bottom of the slot (69).

9. The irregularly shaped ventilation duct curved surface polishing device according to claim 8, characterized in that: The clamping structure also includes a hoisting part, which includes a hoisting frame (101), an assembly plate (102), and a lifting ring (104). The hoisting frame (101) is fixed to the side of the frame (71) and has a U-shaped structure. The assembly plate (102) is fixed to the side of the hoisting frame (101). The assembly plate (102) is adapted to the slot (69) and placed in the slot (69). The assembly plate (102) has a through opening (103). The lifting ring (104) is fixed on the hoisting frame (101).

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