Variable diameter dial for centering cylindrical through holes

Abstract

The application relates to a variable-diameter dividing plate for the centering of cylindrical through holes, which solves the technical problems of fixed diameter, poor adaptability and reliability and relatively high matching precision of existing dividing plates. The dividing plate comprises a base, at least three adjusting assemblies, a rotating disc and a scale plate; the adjusting assembly comprises a rotating rod, a top block, a sliding block, an elastic reset assembly and an adjusting wrench; the base is provided with a plurality of guide groove groups; the rotating disc is coaxially and rotatably connected with the base; the rotating disc is provided with a plurality of rotating disc guide grooves; the adjusting assembly is arranged between the base and the rotating disc and cooperates with the corresponding rotating disc guide grooves and guide groove groups; the rotating rod is rotatably connected with the base; the top block is slidably connected with the first guide groove; the sliding block is slidably connected with the second guide groove; the adjusting wrench is connected with the sliding block and extends out of the hollow track; the elastic reset assembly is connected with the sliding block; the top block and the sliding block are slidably connected with the rotating rod; the top block is slidably connected with the corresponding rotating disc guide groove; and the scale plate is fixedly connected with the base.

Description

TECHNICAL FIELD

[0001] The present application relates to a dividing plate for engineering installation, in particular to a variable diameter dividing plate for centering of cylindrical through hole. BACKGROUND

[0002] In the fields of building construction, equipment manufacturing, large device construction and many other engineering installations, it is often necessary to install and center the parts with cylindrical through hole according to the established laser light path, and the relative position of the center of the cross section of the two ends and the laser light path is observed to adjust the cylindrical through hole, so as to ensure that the position and angle meet the design requirements.

[0003] In order to observe the centering of the cylindrical through hole in real time, a dividing plate is needed to display the position of the laser on the cross section of the through hole. At present, the commonly used method is to use transparent or translucent material to make a circular dividing plate with the same diameter as the cylindrical through hole, and a scale ruler is processed in the center of the dividing plate. When centering, the circular dividing plate is placed on the end face of the cylindrical through hole, and the center of the dividing plate is guaranteed to be concentric with the cross section of the cylindrical through hole through the processing precision and fitting precision, and then the position of the laser on the dividing plate is observed to judge the positional relationship between the laser and the axis of the cylindrical through hole, so as to realize the adjustment and centering of the cylindrical through hole. This kind of dividing plate has simple structure and is easy to process, but since its diameter is fixed, when centering the cylindrical holes with multiple diameters, especially a series of cylindrical holes with small diameter difference, multiple different specifications of dividing plates need to be designed and processed, which not only causes a certain degree of waste, but also is extremely inconvenient in actual use. In addition, in order to guarantee the coaxiality when centering with the cylindrical through hole, the fitting precision between the fixed diameter dividing plate and the cylindrical through hole is relatively high, which easily leads to the problem that the dividing plate cannot be used on the construction site due to the fitting problem, and the adaptability is poor. SUMMARY

[0004] The present application provides a variable diameter dividing plate for centering of cylindrical through hole to solve the technical problems of fixed diameter of the existing dividing plate, unadjustable outer diameter, relatively high fitting precision, poor adaptability and reliability.

[0005] The technical scheme provided by the present application is as follows:

[0006] A variable diameter dividing plate for centering of cylindrical through hole, characterized in that it comprises a base, at least three adjusting assemblies, a rotating disc and a scale plate.

[0007] The base is circular and has a first surface and a second surface arranged opposite to each other; the first surface of the base is provided with a plurality of guide groove groups corresponding to each adjusting assembly; the guide groove group comprises a first guide groove and a second guide groove arranged adjacent to each other and along the radial direction of the base, and the second guide groove has a hollow track penetrating through the base;

[0008] The rotating disc is coaxial with the base and rotatably connected; the rotating disc has a plurality of rotating disc guide slots arranged along the same circumference and corresponding to the respective adjusting assemblies; along the extension direction of the rotating disc guide slots, the distance between the rotating disc guide slots and the axis of the rotating disc gradually decreases; any two rotating disc guide slots are rotationally symmetrical about the axis of the rotating disc;

[0009] The adjusting assembly comprises a rotating rod, a top block, a sliding block, an elastic reset assembly and an adjusting wrench.

[0010] The adjusting assembly is clamped between the base and the rotating disc and cooperates with the corresponding rotating disc guide slot and the corresponding guide slot group; the first end of the rotating rod is rotatably connected with the base; the top block is slidably fitted with the first guide slot and protrudes from the edge of the base; the sliding block is slidably fitted with the second guide slot; the adjusting wrench is connected with the sliding block and protrudes from the second surface of the base; the elastic reset assembly is connected with the sliding block and applies a repulsive force to the sliding block away from the axis of the base; the top block and the sliding block are both slidably fitted with the rotating rod; a plurality of top blocks are respectively slidably fitted with the corresponding rotating disc guide slots so that each top block synchronously extends and retracts.

[0011] The scale plate is fixedly connected with the base coaxially, and a scale ruler is arranged on the scale plate; the axis of the scale ruler coincides with the axis of the base.

[0012] Further, the rotating rod is in the shape of a flat strip and is arc-shaped and parallel to the plane on which the base is located, and the rotating rod has a rotating rod guide slot consistent with the extension direction of the rotating rod; the opening direction of the rotating rod guide slot is parallel to the central axis of the base.

[0013] The top block is provided with a top block positioning pin parallel to the central axis of the base, the first end of the top block positioning pin is inserted into the rotating rod guide slot and slidably fitted with the rotating rod guide slot; the second end of the top block positioning pin is inserted into the rotating disc guide slot and slidably fitted with the rotating disc guide slot.

[0014] The sliding block has a sliding block positioning pin parallel to the central axis of the base, and the sliding block positioning pin is inserted into the rotating rod guide slot and slidably fitted with the rotating rod guide slot.

[0015] Further, the base has a first central circular hole, and a rotating disc support surrounding the first central circular hole is arranged on the first surface.

[0016] The rotating disc has a second central circular hole, and the second central circular hole is rotatably fitted with the rotating disc support.

[0017] Further, the number of the guide slot groups is three; the included angle between the adjacent first guide slot and the second guide slot is 60°.

[0018] Further, the top block has a through hole parallel to the plane of the base; the rotating rod passes through the through hole of the top block; and the first end of the top block positioning pin is located in the through hole.

[0019] Further, the first surface of the base is provided with a base positioning hole; the first end of the rotating rod is provided with a rotating rod positioning pin parallel to the central axis of the base; and the first end of the rotating rod positioning pin is inserted into the base positioning hole, so that the rotating rod and the base are rotatably connected.

[0020] Further, the elastic reset assembly comprises a spring guide shaft and a spring.

[0021] The spring guide shaft is fixedly arranged in the second guide groove along the radial direction of the base.

[0022] The inner end of the spring guide shaft is fixedly connected with the rotating disc support; the sliding block is slidably sleeved on the spring guide shaft; and the spring is sleeved on the spring guide shaft and located between the sliding block and the rotating disc support.

[0023] Further, the rotating disc is circular and is provided with an avoiding groove for avoiding each rotating rod positioning pin.

[0024] Further, in the same adjusting assembly, the top block is located between the sliding block and the first end of the rotating rod.

[0025] Further, the variable-diameter reticle plate further comprises a cover plate; the cover plate covers the rotating disc and is fixedly connected with the base.

[0026] The cover plate has a cover plate guide groove corresponding to each top block positioning pin, a cover plate positioning hole corresponding to each rotating rod positioning pin, and a circular boss corresponding to the rotating disc support.

[0027] The cover plate guide groove is arranged along the radial direction of the base; the second end of the top block positioning pin is inserted into the cover plate guide groove and slidably connected with the cover plate guide groove.

[0028] The second end of the rotating rod positioning pin is inserted into the corresponding cover plate positioning hole and rotatably connected with the cover plate positioning hole.

[0029] The circular boss is connected with the rotating disc support and covers the rotating disc.

[0030] The beneficial effects of the present application are as follows:

[0031] (1) The present application adjusts the position of the sliding block through the elastic reset assembly, drives the position of the top block to change, adjusts the diameter of the reticle plate, and makes the reticle plate suitable for the centering of cylindrical hole of various diameters. Meanwhile, through the cooperation of the spring, the sliding block, the top block and the rotating rod, the top block of the reticle plate can be automatically expanded and fastened in the cylindrical hole, thereby reducing the requirement for the cooperation precision.

[0032] (2) The present application can ensure the synchronous movement of the top block through the rotating disc guide groove on the rotating disc, thereby realizing the high-precision concentricity between the top block circumscribed circle of the scale plate and the center of the scale plate.

[0033] (3) In the same adjusting assembly, the top block is arranged between the sliding block and the rotating rod, so that the pressure force arm of the spring on the sliding block is greater than the reaction force arm of the inner wall of the cylindrical hole on the top block, the spring force is amplified, the spring compression force distance is enhanced, the scale plate can be tightly combined with the inner wall of the cylindrical hole, the top block can stably support the scale plate, and the coaxiality of the scale plate and the cylindrical hole is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 It is an exploded structural schematic view of the variable-diameter scale plate for cylindrical hole centering of the present application;

[0035] Figure 2 It is a base structure schematic view in the embodiment of the present application;

[0036] Figure 3 It is a base, adjusting assembly and dial assembly structure schematic view in the embodiment of the present application;

[0037] Figure 4 It is a base, adjusting assembly, dial and rotating disc assembly structure schematic view in the embodiment of the present application;

[0038] Figure 5 It is a cover plate structure schematic view in the embodiment of the present application;

[0039] Figure 6 It is a variable-diameter scale plate overall assembly front structure schematic view in the embodiment of the present application;

[0040] Figure 7 It is a variable-diameter scale plate overall assembly back structure schematic view in the embodiment of the present application;

[0041] Figure 8 It is a variable-diameter scale plate overall assembly sectional view in the embodiment of the present application.

[0042] The reference signs are as follows:

[0043] 1-base, 101-first guide slot, 102-second guide slot, 103-hollow track, 104-rotating disc support, 105-base positioning hole, 106-guide hole, 107-base screw hole, 2-rotating rod, 201-rotating rod guide slot, 202-rotating rod positioning pin, 3-top block, 301-top block positioning pin, 4-sliding block, 401-sliding block positioning pin, 5-elastic return assembly, 501-spring guide shaft, 502-spring, 6-adjusting wrench, 7-rotating disc, 701-rotating disc guide slot, 702-avoidance slot, 8-scale plate, 801-scale plate screw, 9-cover plate, 901-cover plate guide slot, 902-cover plate positioning hole, 903-circular boss, 904-cover plate screw. DETAILED DESCRIPTION

[0044] Reference Figures 1-8 The embodiment provides a variable-diameter scale plate for centering cylindrical through holes, which comprises a base 1, three adjusting assemblies, a rotating disc 7, a scale plate 8 and a cover plate 9.

[0045] The base 1 is circular and has a first surface, a second surface and a first central circular hole penetrating the first surface and the second surface, and the rotating disc support 104 is arranged on the first surface around the first central circular hole; the base 1 is provided with three guide slot sets corresponding to the adjusting assemblies respectively, a base positioning hole 105 and a base screw hole 107 for fixedly connecting the cover plate 9 on the first surface; each guide slot set comprises the first guide slot 101 and the second guide slot 102 which are adjacent and arranged radially along the base 1, and the included angle between the adjacent first guide slot 101 and the second guide slot 102 is 60°; the second guide slot 102 has the hollow track 103 penetrating the base 1.

[0046] The rotating disc 7 is circular and coaxial with the base 1 and is rotatably connected; the rotating disc 7 has three rotating disc guide slots 701 corresponding to the adjusting assemblies respectively and a second central circular hole; the second central circular hole is rotatably matched with the rotating disc support 104, so that the rotating disc 7 is constrained to rotate around the center axis of the scale plate through the rotating disc support 104 of the base 1; along the extension direction of the rotating disc guide slot 701, the distance between the rotating disc guide slot 701 and the axis of the rotating disc 7 gradually decreases; any two rotating disc guide slots 701 are rotationally symmetrical with the axis of the rotating disc 7 as the center.

[0047] The adjusting assembly comprises the rotating rod 2, the top block 3, the sliding block 4, the elastic return assembly 5 and the adjusting wrench 6, and is clamped between the base 1 and the rotating disc 7 and matched with the corresponding rotating disc guide slot 701 and the corresponding guide slot set.

[0048] The first end of the rotating rod 2 is rotatably connected with the base 1. The rotating rod 2 is in the shape of a flat strip and is in an arc shape parallel to the plane of the base 1 and has a rotating rod guide groove 201 extending in the same direction as the rotating rod 2. The opening direction of the rotating rod guide groove 201 is parallel to the central axis of the base 1. The first end of the rotating rod 2 is provided with a rotating rod positioning pin 202 parallel to the central axis of the base 1. The first end of the rotating rod positioning pin 202 is inserted into the base positioning hole 105, so that the rotating rod 2 is rotatably connected with the base 1. At the same time, the rotating disc 7 is provided with an avoiding groove 702 for avoiding each rotating rod positioning pin 202.

[0049] In the embodiment, the three top blocks 3 are slidably connected with the corresponding first guide grooves 101 and protrude from the edge of the base 1. The top block 3 is provided with a top block positioning pin 301 parallel to the central axis of the base 1. The first end of the top block positioning pin 301 is inserted into the rotating rod guide groove 201 through the through hole on the top block 3 by over-tight fitting and is slidably connected with the rotating rod guide groove 201. The three top blocks 3 move along the fixed track (the first guide groove 101) and can change the outer diameter of the scale plate to realize the centering of different cylindrical hole centers. The length of the top block positioning pin 301 is greater than the thickness of the top block 3. The second end of the top block positioning pin 301 is inserted into the rotating disc guide groove 701 after extending outwards by 5 mm and is slidably connected with the rotating disc guide groove 701. The three top block positioning pins 301 are constrained to move synchronously by the rotating disc guide groove 701. The slider positioning pin 401 drives the top block 3 to expand outward synchronously through the rotating rod 2, so as to ensure that the outer circle of the end of the top block 3 is concentric with the center of the scale plate 8. The top block 3 has a through hole parallel to the plane of the base 1. The rotating rod 2 passes through the through hole of the top block 3. The first end of the top block positioning pin 301 is located in the through hole.

[0050] The slider 4 is slidably connected with the second guide groove 102. The slider 4 has a slider positioning pin 401 parallel to the central axis of the base 1. The slider positioning pin 401 is inserted into the rotating rod guide groove 201 through the through hole on the slider 4 by over-tight fitting and is slidably connected with the rotating rod guide groove 201.

[0051] It can be understood that the top block 3 and the slider 4 move along the radial direction of the scale plate by being constrained by the first guide groove 101 and the second guide groove 102 on the base 1. The synchronous movement of the top block 3 and the slider 4 is realized by the rotating rod guide groove 201.

[0052] The adjusting wrench 6 is connected with the sliding block 4 and extends out of the hollow track 103 and protrudes from the second surface of the base 1; when the scale plate is installed, the sliding block 4 can be gathered to the center of the scale plate by pinching the adjusting wrench 6, the sliding block 4 drives the top block 3 to retract into the scale plate through the rotating rod 2, at this time, the scale plate is in the smallest diameter state, then the scale plate is placed into the cylindrical hole, and the adjusting wrench 6 is loosened, the rotating rod 2 drives the top block 3 to expand outward under the action of the spring, and the scale plate is automatically adjusted and fixed to the correct position, thereby realizing the wide application of the scale plate to various cylindrical hole diameters.

[0053] The elastic reset assembly 5 is connected with the sliding block 4 and is used for applying a repulsive force to the sliding block 4 away from the axis of the base 1, specifically, the elastic reset assembly 5 includes a spring guide shaft 501 and a spring 502; the spring guide shaft 501 is fixedly arranged in the second guide groove 102 along the radial direction of the base 1; the inner end of the spring guide shaft 501 is fixedly connected with the rotating disc support 104; the sliding block 4 is slidably sleeved on the spring guide shaft 501; the spring 502 is sleeved on the spring guide shaft 501 and is located between the sliding block 4 and the rotating disc support 104; specifically, the spring guide shaft 501 penetrates into the guide hole 106 on the base 1, and the spring 502 applies an outward elastic force to the sliding block 4, so that the three top blocks 3 can abut against the inner wall of the cylindrical surface when the scale plate is placed into the cylindrical hole, thereby ensuring that the center of the scale plate coincides with the axis of the cylindrical hole.

[0054] The top block 3 and the sliding block 4 are slidably connected with the rotating rod 2; when the adjusting wrench 6 moves to the axis of the base 1 under the action of an external force, the top block 3 can be retracted to the axis of the base 1 through the rotating rod 2; the top block 3 is slidably connected with the corresponding rotating disc guide groove 701, and synchronous extension and contraction of the top block 3 is realized through cooperation of the rotating disc 7, the rotating disc guide groove 701 arranged on the rotating disc 7 and the rotating rod 2, thereby ensuring the concentricity of the outer circle of the scale plate and the overall structure. In the same adjusting assembly, the top block 3 is located between the sliding block 4 and the first end of the rotating rod 2, so as to ensure that the pressure arm of the spring 502 to the sliding block 4 is greater than the reaction force arm of the inner wall of the cylindrical hole to the top block 3, thereby enhancing the compression force distance of the spring 502, ensuring that the top block 3 can stably support the scale plate, and ensuring the coaxiality of the scale plate and the cylindrical hole.

[0055] The scale plate 8 is coaxially fixedly installed on the second surface of the base 1 through scale plate screws 801, the scale plate screws 801 are three in number and are distributed at an angle of 120°; the scale plate 8 is provided with a scale mark, and the axis of the scale mark coincides with the axis of the base 1; specifically, the scale plate 8 is made of transparent or translucent material, in this embodiment, the scale plate 8 is made of frosted organic glass, the thickness is 2 mm, and a scale mark with a range of ±10 mm and an interval of 1 mm is processed in the center.

[0056] The cover plate 9 covers the rotating disc 7 and is fixedly connected with the base 1 through cover plate screws 904; the cover plate 9 has cover plate guide grooves 901 corresponding to the top block positioning pins 301 respectively, cover plate positioning holes 902 corresponding to the rotating rod positioning pins 202 respectively and a circular boss 903 corresponding to the rotating disc support 104.

[0057] The cover plate guide grooves 901 are arranged along the radial direction of the base 1; the second ends of the top block positioning pins 301 are inserted into the cover plate guide grooves 901 and are slidably matched with the cover plate guide grooves 901; the second ends of the rotating rod positioning pins 202 are inserted into the corresponding cover plate positioning holes 902 and are rotatably matched with the cover plate positioning holes 902; the circular boss 903 is matched with the rotating disc support 104 and covers the rotating disc 7, for restricting the axial movement of the rotating disc 7; when the cover plate 9 is installed, the screw mounting hole positions need to be aligned to ensure that the cover plate screws 904 pass through and are screwed into the base screw holes 107 smoothly, and at the same time, the rotating rod positioning pins 202 are inserted into the cover plate positioning holes 902 to further fix the rotating rod positioning pins 202, and the top block positioning pins 301 are located in the cover plate guide grooves 901 to restrict the radial movement of the top block positioning pins 301 along the scale plate.

[0058] The variable-diameter scale plate provided in the embodiment is made of light-weight density materials such as aluminum alloy, so as to reduce the influence of gravity when the scale plate is used and improve the accuracy of alignment.

Claims

1. A variable diameter dial for centering cylindrical through holes, characterized by: The device comprises a base (1), at least three adjusting assemblies, a rotating disc (7) and a scale plate (8); The base (1) is circular and has a first surface and a second surface arranged oppositely; the first surface of the base (1) is provided with a plurality of guide groove sets corresponding to the adjusting assemblies respectively; each guide groove set comprises a first guide groove (101) and a second guide groove (102) arranged adjacently and radially along the base (1), and the second guide groove (102) has a hollow track (103) penetrating through the base (1); The rotating disc (7) is coaxially and rotatably connected with the base (1); the rotating disc (7) has a plurality of rotating disc guide grooves (701) arranged along the same circumference and corresponding to the adjusting assemblies respectively; along the extension direction of the rotating disc guide grooves (701), the distance between the rotating disc guide grooves (701) and the axis of the rotating disc (7) gradually decreases; any two rotating disc guide grooves (701) are rotationally symmetrical about the axis of the rotating disc (7); The adjusting assembly comprises a rotating rod (2), a top block (3), a sliding block (4), an elastic reset assembly (5) and an adjusting wrench (6); The adjusting assembly is clamped between the base (1) and the rotating disc (7) and cooperates with the corresponding rotating disc guide groove (701) and the corresponding guide groove set; the first end of the rotating rod (2) is rotatably connected with the base (1); the top block (3) is slidably fitted with the first guide groove (101) and protrudes from the edge of the base (1); the sliding block (4) is slidably fitted with the second guide groove (102); the adjusting wrench (6) is connected with the sliding block (4) and protrudes from the second surface of the base (1) through the hollow track (103); the elastic reset assembly (5) is connected with the sliding block (4) and applies a repulsive force to the sliding block (4) away from the axis of the base (1); the top block (3) and the sliding block (4) are slidably fitted with the rotating rod (2); the plurality of top blocks (3) are slidably fitted with the corresponding rotating disc guide grooves (701) respectively so that each top block (3) synchronously extends and retracts; The scale plate (8) is fixedly connected with the base (1) coaxially and is provided with a scale on the scale plate (8); the axis of the scale coincides with the axis of the base (1).

2. The variable-diameter dividing plate for centering cylindrical through holes according to claim 1, wherein: The rotating rod (2) is in the shape of a flat strip and has an arc shape parallel to the plane of the base (1); the rotating rod (2) has a rotating rod guide groove (201) consistent with the extension direction of the rotating rod (2); the opening direction of the rotating rod guide groove (201) is parallel to the central axis of the base (1); The top block (3) is provided with a top block positioning pin (301) parallel to the central axis of the base (1); the first end of the top block positioning pin (301) is inserted into the rotating rod guide groove (201) and is slidably fitted with the rotating rod guide groove (201); the second end of the top block positioning pin (301) is inserted into the rotating disc guide groove (701) and is slidably fitted with the rotating disc guide groove (701); The slider (4) has a slider positioning pin (401) parallel to the central axis of the base (1), which is inserted into the rotating rod guide groove (201) and can be slidably matched with the rotating rod guide groove (201).

3. The variable diameter dividing rule for centering cylindrical through holes according to claim 2, wherein: The base (1) has a first central circular hole, and a rotating disc support (104) is arranged around the first central circular hole on the first surface; The rotating disc (7) has a second central circular hole which is rotatably matched with the rotating disc support (104).

4. The variable diameter dividing rule for centering cylindrical through holes according to claim 3, wherein: The number of the guide groove groups is three; the included angle between the adjacent first guide groove (101) and the second guide groove (102) is 60°.

5. The variable diameter dividing rule for centering cylindrical through holes according to claim 4, wherein: The top block (3) has a through hole parallel to the plane of the base (1); the rotating rod (2) passes through the through hole of the top block (3); and the first end of the top block positioning pin (301) is located in the through hole.

6. The variable diameter dividing rule for centering cylindrical through holes according to claim 5, wherein: The first surface of the base (1) is provided with a base positioning hole (105); the first end of the rotating rod (2) is provided with a rotating rod positioning pin (202) parallel to the central axis of the base (1); and the first end of the rotating rod positioning pin (202) is inserted into the base positioning hole (105) so that the rotating rod (2) is rotatably matched with the base (1).

7. The variable diameter dividing rule for centering cylindrical through holes according to claim 6, wherein: The elastic return assembly (5) comprises a spring guide shaft (501) and a spring (502); The spring guide shaft (501) is fixedly arranged in the second guide groove (102) in the radial direction of the base (1); The inner end of the spring guide shaft (501) is fixedly connected with the rotating disc support (104); the slider (4) is slidably sleeved on the spring guide shaft (501); and the spring (502) is sleeved on the spring guide shaft (501) and located between the slider (4) and the rotating disc support (104).

8. The variable diameter dividing rule for centering cylindrical through holes according to claim 7, wherein: The rotating disc (7) is circular and is provided with an avoiding groove (702) for avoiding each rotating rod positioning pin (202).

9. The variable diameter dividing rule for centering cylindrical through holes according to claim 8, wherein: In the same adjusting assembly, the top block (3) is located between the slider (4) and the first end of the rotating rod (2).

10. The variable diameter dividing rule for centering cylindrical through holes according to claim 9, wherein: The variable diameter dividing rule further comprises a cover plate (9); and the cover plate (9) covers the rotating disc (7) and is fixedly connected with the base (1). The cover plate (9) has a cover plate guide slot (901) corresponding to each top block positioning pin (301), a cover plate positioning hole (902) corresponding to each rotating rod positioning pin (202), and a circular boss (903) corresponding to the rotating disc support (104); The cover plate guide slot (901) is arranged along the radial direction of the base (1); the second end of the top block positioning pin (301) is inserted into the cover plate guide slot (901) and is slidably matched with the cover plate guide slot (901); The second end of the rotating rod positioning pin (202) is inserted into the corresponding cover plate positioning hole (902) and is rotatably matched with the cover plate positioning hole (902); The circular boss (903) is matched with the rotating disc support (104) and covers the rotating disc (7).

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