A product appearance defect detection device based on machine vision

Abstract

The present invention relates to the technical field of product appearance defect detection devices, and discloses a product appearance defect detection device based on machine vision, including a bottom frame, a rotation detection component is installed on the inner wall of the top of the bottom frame, and an object placement component is provided on the top of the bottom frame. After the visual camera rotates 360°, the four sides of the object are photographed, and the mounting bracket rotates in the same direction to push the inner gear ring to rotate 30° again. At this time, the rotation of the inner gear ring drives the gear three to rotate, and the rotation of the gear three drives the gear one and the gear two to rotate, so that the rotating shaft one, the rotating shaft two, the outer rubber sleeve one and the outer rubber sleeve two rotate to drive the object to rotate. At this time, the top surface and the bottom surface of the object are rotated to the side, and then the mounting bracket rotates 30° in the opposite direction, and then rotates 180° to take pictures of the undetected surface of the object for detection, thereby solving the problem that the existing defect detection device is easy to cause surface damage of the object and the detection time is long when detecting cylindrical objects.

Description

Technical Field

[0001] The present invention relates to the technical field of product appearance defect detection devices, and in particular to a product appearance defect detection device based on machine vision. Background Art

[0002] Machine vision is a rapidly developing branch of artificial intelligence. Simply put, machine vision is to use machines to replace human eyes for measurement and judgment. The machine vision system uses machine vision products (i.e. image acquisition devices, divided into CMOS and CCD) to convert the captured target into image signals, transmit them to a dedicated image processing system, obtain the morphological information of the captured target, and convert them into digital signals based on pixel distribution, brightness, color and other information; the image system performs various operations on these signals to extract the characteristics of the target, and then controls the equipment action on site based on the judgment results.

[0003] Existing cylindrical objects are inspected in a vertical state. This inspection method prevents the visual camera from inspecting the bottom. When inspecting the bottom, the position of the cylindrical object needs to be changed so that the bottom of the object is within the shooting range of the visual camera. This operation process can easily cause damage to the surface of the object and also results in a long inspection time. Summary of the invention

[0004] The present invention provides a device for detecting product appearance defects based on machine vision, which solves the problems raised by the above-mentioned background technology.

[0005] The present invention provides the following technical solution: a product appearance defect detection device based on machine vision, comprising a bottom frame, a rotation detection component is installed on the inner wall of the top of the bottom frame, and an object placement component is provided on the top of the bottom frame;

[0006] The rotation detection assembly comprises a bottom rotating bracket, a rotating servo motor is installed on the inner wall of the bottom rotating bracket, a rotating gear is fixedly sleeved on the power output shaft of the rotating servo motor, an inner gear ring is meshed on the outer edge of the rotating gear, the inner gear ring is installed on the bottom frame, a mounting bracket is installed on the top of the bottom rotating bracket, a rotating screw is provided on the inner wall of the mounting bracket, a lifting bracket is threadedly connected to the outer edge of the rotating screw, and a visual camera is installed on the outer wall of the lifting bracket;

[0007] The article placement assembly includes a fixed bracket, a side bracket is installed on the outer edge of the fixed bracket, and the inner walls of the side bracket and the fixed bracket are provided with a rotating shaft 1 and a rotating shaft 2, and the outer edges of the rotating shaft 1 and the rotating shaft 2 are respectively movably sleeved with an outer rubber sleeve 1 and an outer rubber sleeve 2, and the outer edges of the rotating shaft 1 and the rotating shaft 2 are respectively fixedly sleeved with a gear 1 and a gear 2, and the outer edges of the gear 1 and the gear 2 are both meshed with a gear 3, and the gear 3 is movably connected to the fixed bracket, and the outer edge of the gear 3 is meshed with a top gear ring.

[0008] As a preferred technical solution of the present invention, a worm wheel is fixedly sleeved on the outer edge of the rotating screw, a worm is meshed on the outer edge of the worm wheel, and a handle is fixedly mounted on the outer edge of the worm.

[0009] As a preferred technical solution of the present invention, a vertical rod is fixedly mounted on the inner wall of the bottom rotating bracket, and the lifting bracket is slidably connected to the vertical rod.

[0010] As a preferred technical solution of the present invention, an inner connecting rod is provided on the inner periphery of the bottom rotating bracket, and a limiting wheel is movably sleeved on the outer edge of the inner connecting rod; an outer connecting rod is provided on the outer periphery of the bottom rotating bracket, and a roller is movably sleeved on the outer edge of the outer connecting rod, and the outer walls of the roller and the limiting wheel are respectively in contact with the outer edge and inner edge of the inner gear ring.

[0011] As a preferred technical solution of the present invention, a support bracket is fixedly mounted on the bottom of the bottom rotating bracket, and a support wheel is installed on the inner wall of the support bracket.

[0012] As a preferred technical solution of the present invention, a support rod is fixedly mounted on the bottom of the fixed bracket, and the top gear ring is movably connected to the support rod.

[0013] As a preferred technical solution of the present invention, a first contact piece is fixedly mounted on the outer wall of the top gear ring, and a second contact piece is fixedly mounted on the outer wall of the mounting bracket.

[0014] As a preferred technical solution of the present invention, the outer edges of the first and second rotating shafts are both provided with mounting grooves, the inner walls of the mounting grooves are fixedly equipped with cross bars, and the outer edges of the cross bars are movably sleeved with clamping blocks.

[0015] As a preferred technical solution of the present invention, a circular hole is formed at one end of the mounting groove away from the cross bar, a supporting spring is formed on the inner wall of the circular hole, and limiting slots are formed at both ends of the outer rubber sleeve one and both ends of the outer rubber sleeve two.

[0016] As a preferred technical solution of the present invention, the inner walls of the outer rubber sleeve 1 and the outer rubber sleeve 2 are fixedly equipped with limit strips, and the outer edges of the rotating shaft 1 and the rotating shaft 2 are both provided with limit grooves.

[0017] The present invention has the following beneficial effects:

[0018] 1. The product appearance defect detection device based on machine vision, after the visual camera rotates 360°, the four sides of the object are photographed, and then the mounting bracket rotates in the same direction to push the inner gear ring to rotate another 30°. At this time, the rotation of the inner gear ring drives gear three to rotate, and the rotation of gear three drives gear one and gear two to rotate, so that the rotating shaft one, rotating shaft two, outer rubber sleeve one and outer rubber sleeve two rotate to drive the object to rotate. At this time, the top and bottom surfaces of the object are rotated to the side, and then the mounting bracket is rotated in the opposite direction by 30°, and then rotated 180° to take pictures of the undetected surfaces of the object for detection, so that the device can perform four-sided shooting detection on cylindrical objects and can also perform comprehensive detection, thereby solving the problem that the existing appearance defect detection device needs to manually move the bottom of the cylindrical object into the shooting range of the visual camera when detecting cylindrical objects, and the problem that the surface of the object is easily damaged and the detection time is long during this operation is easily caused.

[0019] 2. The product appearance defect detection device based on machine vision, through the setting of the card block, when disassembled, by inserting the flat strip into the limit card slot, the card block changes from an inclined state to a horizontal state, and the card block is not in contact with the limit card slot. At this time, the outer rubber sleeve 1 and the outer rubber sleeve 2 can be removed from the rotating shaft 1 and the rotating shaft 2, so that the device is easy to disassemble for maintenance. The outer rubber sleeve 1 and the outer rubber sleeve 2 are made of rubber material, which can increase the friction of the object and prevent the object from slipping between the outer rubber sleeve 1 and the outer rubber sleeve 2. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the front three-dimensional structure of the present invention;

[0021] Figure 2 It is a schematic diagram of the internal structure of the present invention;

[0022] Figure 3 It is a schematic diagram of the top structure of the present invention;

[0023] Figure 4 This is a schematic diagram of the cross-sectional structure of the article placement assembly of the present invention;

[0024] Figure 5 For the present invention Figure 4 A is an enlarged structural diagram;

[0025] Figure 6 It is a schematic diagram of the structure of the components of the present invention;

[0026] Figure 7 It is a structural schematic diagram of the rotation detection component of the present invention;

[0027] Figure 8 For the present invention Figure 7 The enlarged structural diagram at B in FIG.

[0028] Fig. 9 This is a schematic diagram of the three positions of the gear of the present invention;

[0029] Fig.10 For the present invention Fig. 9 The enlarged structural diagram at C in the figure.

[0030] In the figure: 1. bottom frame; 2. rotation detection component; 3. object placement component;

[0031] 201, bottom rotating bracket; 202, rotating servo motor; 203, rotating gear; 204, inner gear ring; 205, inner connecting rod; 206, limiting wheel; 207, outer connecting rod; 208, roller; 209, supporting bracket; 210, supporting wheel; 211, mounting bracket; 212, rotating screw; 213, worm gear; 214, worm; 215, handle; 216, vertical rod; 217, lifting bracket; 218, contact piece 2; 219, visual camera;

[0032] 301, fixed bracket; 302, side bracket; 303, shaft one; 304, shaft two; 305, outer rubber sleeve one; 306, outer rubber sleeve two; 307, gear one; 308, gear two; 309, gear three; 310, support rod; 311, top gear ring; 312, mounting groove; 313, cross bar; 3131, block; 314, round hole; 315, support spring; 316, limit groove; 317, limit strip; 318, contact piece one; 319, limit slot. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] See also Figure 1-10A product appearance defect detection device based on machine vision comprises a bottom frame 1, a rotation detection component 2 is installed on the inner wall of the top of the bottom frame 1, and an object placement component 3 is arranged on the top of the bottom frame 1. The rotation detection component 2 rotates around the object placement component 3, so that the visual camera 219 on the rotation detection component 2 can take pictures of the objects on the rotation detection component 2 for detection. After the rotation detection component 2 rotates 360°, it is rotated 30° in the direction so that the rotation detection component 2 is operated. At this time, the bottom and top of the object on the rotation detection component 2 that are not detected are rotated to the side, and then the rotation detection component 2 rotates 30° and then rotates 180° to take pictures of the undetected surface of the object.

[0035] The rotation detection component 2 includes a bottom rotating bracket 201, a rotating servo motor 202 is installed on the inner wall of the bottom rotating bracket 201, a rotating gear 203 is fixedly sleeved on the power output shaft of the rotating servo motor 202, an inner gear ring 204 is meshed on the outer edge of the rotating gear 203, and the inner gear ring 204 is installed on the bottom frame 1, and a mounting bracket 211 is installed on the top of the bottom rotating bracket 201, a rotating screw rod 212 is provided on the inner wall of the mounting bracket 211, and a lifting bracket 217 is threadedly connected to the outer edge of the rotating screw rod 212, and a visual camera 219 is installed on the outer wall of the lifting bracket 217, and the rotating servo motor 202 is rotated to drive the rotating gear 203 to rotate, so that the rotating gear 203 rotates in the inner gear ring 204, so that the bottom rotating bracket 201, the mounting bracket 211 and the visual camera 219 can rotate, so that the visual camera 219 can perform all-round detection of the object;

[0036] The article placement assembly 3 includes a fixed bracket 301, a side bracket 302 is installed on the outer edge of the fixed bracket 301, and a rotating shaft 1 303 and a rotating shaft 2 304 are provided on the inner walls of the side bracket 302 and the fixed bracket 301. The outer edges of the rotating shaft 1 303 and the rotating shaft 2 304 are respectively movably sleeved with an outer rubber sleeve 1 305 and an outer rubber sleeve 2 306, and the outer edges of the rotating shaft 1 303 and the rotating shaft 2 304 are respectively fixedly sleeved with a gear 1 307 and a gear 2 308. The gear 1 307 and the gear 2 308 are respectively fixedly sleeved. The outer edges of 8 are all meshed with gear three 309, and gear three 309 is movably connected to the fixed bracket 301. The outer edges of gear three 309 are meshed with top gear ring 311, and the top gear ring 311 rotates to drive gear three 309 to rotate. The rotation of gear three 309 drives gear one 307 and gear two 308 to rotate in the same direction, so that shaft one 303 and shaft two 304 can be rotated, and at this time, the objects on the outer rubber sleeve one 305 and the outer rubber sleeve two 306 can be rotated.

[0037] In a preferred embodiment, a worm wheel 213 is fixedly sleeved on the outer edge of the rotating screw 212, a worm 214 is meshed on the outer edge of the worm wheel 213, and a handle 215 is fixedly installed on the outer edge of the worm 214. By rotating the handle 215, the worm 214 can be driven to rotate, the worm 214 can be driven to rotate by the worm wheel 213, and the worm wheel 213 can be driven to rotate by the rotating screw 212, so that the lifting bracket 217 can be raised and lowered.

[0038] In a preferred embodiment, the inner wall of the bottom rotating bracket 201 is fixedly equipped with a vertical rod 216, and the lifting bracket 217 is slidably connected to the vertical rod 216. The vertical rod 216 serves as a limit for the lifting bracket 217. The vertical rod 216 can enable the lifting bracket 217 to perform stable vertical lifting and lowering, thereby improving the stability of the device.

[0039] In a preferred embodiment, an inner connecting rod 205 is provided on the inner periphery of the bottom rotating bracket 201, and a limiting wheel 206 is movably sleeved on the outer edge of the inner connecting rod 205. An outer connecting rod 207 is provided on the outer periphery of the bottom rotating bracket 201, and a roller 208 is movably sleeved on the outer edge of the outer connecting rod 207. The outer walls of the roller 208 and the limiting wheel 206 are respectively fitted with the outer edge and inner edge of the inner gear ring 204. Through the setting of the roller 208 and the limiting wheel 206, the roller 208 and the limiting wheel 206 can limit the bottom rotating bracket 201, so that the rotating gear 203 can mesh with the inner gear ring 204 and will not separate during rotation, thereby improving the rationality of the device.

[0040] In a preferred embodiment, a support bracket 209 is fixedly installed at the bottom of the bottom rotating bracket 201, and a support wheel 210 is installed on the inner wall of the support bracket 209. By utilizing the setting of the support bracket 209 and the support wheel 210, the support bracket 209 and the support wheel 210 can support the weight of the servo motor 202 and the mounting bracket 211 of the bottom rotating bracket 201, so that the roller 208 and the limiting wheel 206 are in contact with the inner gear ring 204 more stably, thereby improving the stability of the device.

[0041] In a preferred embodiment, the bottom of the fixed bracket 301 is fixedly equipped with a support rod 310, and the top ring gear 311 is movably connected to the support rod 310. Since the fixed bracket 301 is fixed to the bottom frame 1 through the support rod 310, the top ring gear 311 needs to rotate when the gear three 309 is to rotate, thereby improving the rationality of the device.

[0042] In a preferred embodiment, the outer wall of the top gear ring 311 is fixedly equipped with a contact piece 1 318, and the outer wall of the mounting bracket 211 is fixedly equipped with a contact piece 218. When the mounting bracket 211 rotates 360°, the contact piece 218 contacts the contact piece 1 318, and then the mounting bracket 211 continues to rotate to make the top gear ring 311 rotate.

[0043] In a preferred embodiment, the outer edges of the rotating shaft 1 303 and the rotating shaft 2 304 are both provided with mounting grooves 312, the inner walls of the mounting grooves 312 are fixedly equipped with a cross bar 313, and the outer edge of the cross bar 313 is movably sleeved with a clamping block 3131. By setting the clamping block 3131, the clamping block 3131 can limit the two ends of the outer rubber sleeve 1 305 and the outer rubber sleeve 2 306, so that the outer rubber sleeve 1 305 and the outer rubber sleeve 2 306 can be fixed on the rotating shaft 1 303 and the rotating shaft 2 304 respectively, so that the outer rubber sleeve 1 305 and the outer rubber sleeve 2 306 will not be displaced when the rotating shaft 1 303 and the rotating shaft 2 304 rotate.

[0044] In a preferred embodiment, a circular hole 314 is provided at one end of the mounting groove 312 away from the cross bar 313, and a support spring 315 is provided on the inner wall of the circular hole 314. Both ends of the outer rubber sleeve 1 305 and both ends of the outer rubber sleeve 2 306 are provided with limit slots 319. By utilizing the setting of the support spring 315, the support spring 315 is used to support the block 3131 so that the block 3131 can be firmly stuck in the limit slot 319. During disassembly, the flat strip is inserted into the limit slot 319 so that the block 3131 changes from an inclined state to a horizontal state. At this time, the outer rubber sleeve 1 305 and the outer rubber sleeve 2 306 can be pulled out from the rotating shaft 1 303 and the rotating shaft 2 304 respectively.

[0045] In a preferred embodiment, the inner walls of the outer rubber sleeve 1 305 and the outer rubber sleeve 2 306 are fixedly assembled with a limit strip 317, and the outer edges of the rotating shaft 1 303 and the rotating shaft 2 304 are both provided with a limit groove 316. By using the limit strip 317 and the limit groove 316 in coordination, when the outer rubber sleeve 1 305 and the outer rubber sleeve 2 306 are installed on the rotating shaft 1 303 and the rotating shaft 2 304, the limit groove 319 and the block 3131 are easy to align, so that the outer rubber sleeve 1 305 and the outer rubber sleeve 2 306 are easy to disassemble and install.

[0046] Working principle: When in use, place the cylindrical object to be inspected on the outer rubber sleeve 1 305 and the outer rubber sleeve 2 306, and then drive the rotating gear 203 to rotate by rotating the power output shaft of the rotating servo motor 202. At this time, the bottom rotating bracket 201, the rotating servo motor 202 and the rotating gear 203 rotate around the inner gear ring 204, and the mounting bracket 211 and the visual camera 219 rotate around the object. The visual camera 219 takes a picture of the object for inspection. When the visual camera 219 rotates 360°, the four sides of the object are photographed, and then the mounting bracket 211 is installed. 1 is rotating in the same direction. At this time, the visual camera 219 on the mounting bracket 211 contacts the contact piece 1 318 on the inner gear ring 204. The mounting bracket 211 rotates to push the inner gear ring 204 to rotate another 30°. At this time, the rotation of the inner gear ring 204 drives the gear 3 309 to rotate. The rotation of the gear 3 309 drives the gear 1 307 and the gear 2 308 to rotate in the same direction. At this time, the rotating shaft 1 303 and the rotating shaft 2 304 follow the gear 1 307 and the gear 2 308 to rotate, so that the outer rubber sleeve 1 305 and the outer rubber sleeve 2 306 can be rotated. The outer rubber sleeve 1 305 and the outer rubber sleeve 2 When the rubber sleeve 2 306 is rotated, it can drive the object to rotate. At this time, the top and bottom surfaces of the object are rotated to the side, and then the mounting bracket 211 is rotated in the opposite direction by 30°, and then rotated 180° to take photos of the undetected surface of the object for detection. When the outer rubber sleeve 1 305 and the outer rubber sleeve 2 306 are used for a long time and are seriously worn, at this time, the rotating shaft 1 303 and the rotating shaft 2 304 are removed from the fixed bracket 301, and then the flat strip is inserted into the limit card slot 319. At this time, the card block 3131 changes from an inclined state to a horizontal state. At this time, the card block 3131 does not contact the limit card slot 319. When installing, the outer rubber sleeve 1 305 and the outer rubber sleeve 2 306 are respectively inserted into the rotating shaft 1 303 and the rotating shaft 2 304, and the clamping block 3131 is compressed. When the tail ends of the outer rubber sleeve 1 305 and the outer rubber sleeve 2 306 contact the clamping block 3131, the clamping block 3131 at the head contacts the limiting clamping groove 319 at the head of the outer rubber sleeve 1 305 and the outer rubber sleeve 2 306, and the outer rubber sleeve 1 305 and the outer rubber sleeve 2 306 are fixed.

[0047] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0048] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A device for detecting product appearance defects based on machine vision, comprising a bottom frame (1), characterized in that: A rotation detection component (2) is installed on the inner wall of the top of the bottom frame (1), and an object placement component (3) is provided on the top of the bottom frame (1); The rotation detection assembly (2) comprises a bottom rotating bracket (201), a rotating servo motor (202) is mounted on the inner wall of the bottom rotating bracket (201), a rotating gear (203) is fixedly sleeved on the power output shaft of the rotating servo motor (202), an inner gear ring (204) is meshed on the outer edge of the rotating gear (203), the inner gear ring (204) is mounted on the bottom frame (1), a mounting bracket (211) is mounted on the top of the bottom rotating bracket (201), a rotating screw rod (212) is disposed on the inner wall of the mounting bracket (211), a lifting bracket (217) is threadedly connected to the outer edge of the rotating screw rod (212), and a visual camera (219) is mounted on the outer wall of the lifting bracket (217); The article placement assembly (3) comprises a fixed bracket (301), the outer edge of which is mounted a side bracket (302), the inner walls of the side bracket (302) and the fixed bracket (301) are provided with a first rotating shaft (303) and a second rotating shaft (304), the outer edges of the first rotating shaft (303) and the second rotating shaft (304) are respectively movably sleeved with an outer rubber sleeve (305) and an outer rubber sleeve (306), the outer edges of the first rotating shaft (303) and the second rotating shaft (304) are respectively fixedly sleeved with a first gear (307) and a second gear (308), the outer edges of the first gear (307) and the second gear (308) are both meshed with a third gear (309), the third gear (309) is movably connected to the fixed bracket (301), and the outer edge of the third gear (309) is meshed with a top gear ring (311); The outer edges of the first rotating shaft (303) and the second rotating shaft (304) are both provided with mounting grooves (312), the inner walls of the mounting grooves (312) are fixedly provided with cross bars (313), and the outer edges of the cross bars (313) are movably sleeved with clamping blocks (3131); A circular hole (314) is formed at one end of the mounting groove (312) away from the cross bar (313), a supporting spring (315) is formed on the inner wall of the circular hole (314), and limiting slots (319) are formed at both ends of the outer rubber sleeve 1 (305) and both ends of the outer rubber sleeve 2 (306).

2. The device for detecting product appearance defects based on machine vision according to claim 1, characterized in that: A worm wheel (213) is fixedly sleeved on the outer edge of the rotating screw rod (212), a worm (214) is meshed on the outer edge of the worm wheel (213), and a handle (215) is fixedly mounted on the outer edge of the worm (214).

3. The device for detecting product appearance defects based on machine vision according to claim 1, characterized in that: A vertical rod (216) is fixedly mounted on the inner wall of the bottom rotating bracket (201), and the lifting bracket (217) is slidably connected to the vertical rod (216).

4. The device for detecting product appearance defects based on machine vision according to claim 1, characterized in that: An inner connecting rod (205) is provided on the inner periphery of the bottom rotating bracket (201), and a limiting wheel (206) is movably sleeved on the outer edge of the inner connecting rod (205). An outer connecting rod (207) is provided on the outer periphery of the bottom rotating bracket (201), and a roller (208) is movably sleeved on the outer edge of the outer connecting rod (207). The outer walls of the roller (208) and the limiting wheel (206) are respectively fitted with the outer edge and the inner edge of the inner gear ring (204).

5. The device for detecting product appearance defects based on machine vision according to claim 1, characterized in that: A support bracket (209) is fixedly mounted on the bottom of the bottom rotating bracket (201), and a support wheel (210) is installed on the inner wall of the support bracket (209).

6. The device for detecting product appearance defects based on machine vision according to claim 1, characterized in that: A support rod (310) is fixedly mounted on the bottom of the fixed bracket (301), and the top gear ring (311) is movably connected to the support rod (310).

7. The device for detecting product appearance defects based on machine vision according to claim 1, characterized in that: A first contact piece (318) is fixedly mounted on the outer wall of the top gear ring (311), and a second contact piece (218) is fixedly mounted on the outer wall of the mounting bracket (211).

8. The device for detecting product appearance defects based on machine vision according to claim 1, characterized in that: The inner walls of the outer rubber sleeve 1 (305) and the outer rubber sleeve 2 (306) are fixedly assembled with a limit strip (317), and the outer edges of the rotating shaft 1 (303) and the rotating shaft 2 (304) are both provided with a limit groove (316).

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