Rotary elastic shoe buckle

Abstract

The utility model relates to the field of rotary shoe buckles, in particular to a rotary elastic shoe buckle which comprises a fixed base, a mounting seat capable of accommodating a shoelace is arranged at the upper end of the fixed base, and a take-up device capable of winding and rotating the shoelace is mounted in the mounting seat. A fixing shell capable of driving the take-up device to rotate is arranged on the outer side of the take-up device, a rotating upper cover capable of rebounding is connected to the outer side of the fixing shell in a clamped mode, the fixing base, the installation base, the take-up device, the fixing shell, the rotating upper cover and other components are tightly combined, and stability and durability of the structure are guaranteed. Due to the clamping and meshing design of all the components, the whole device is smoother during rotation and operation, and the phenomenon of failures or looseness is not prone to occurring. And the concave tooth block and the convex tooth block are in meshed connection, so that the connection strength between the fixed shell and the take-up device is improved, and the rotation between the fixed shell and the take-up device is smoother.

Description

Technical Field

[0001] The utility model relates to the field of rotating shoe buckles, in particular to a rotating elastic shoe buckle. Background Art

[0002] Shoelaces are ropes used to adjust the tightness of the shoe upper and ensure the comfort of the foot. Shoelaces have always been fastened by cross-knotting the shoelaces, which is very cumbersome. In addition, the shoelaces are often too tight, too loose or loose when walking or exercising, causing a lot of inconvenience.

[0003] Children usually tie their shoelaces with the help of adults. Many children simply stop tying their shoelaces once they get loose, so it is common for children to step on their shoelaces and fall down.

[0004] The shoelaces and shoe buckles currently in use cannot rebound, and children often break them apart when using them, which is inconvenient to use. Therefore, we propose a rotating elastic shoe buckle. Utility Model Content

[0005] The purpose of the utility model is to provide a rotating elastic shoe buckle to solve the problems raised in the above background technology.

[0006] To achieve the above-mentioned purpose, a rotating elastic shoe buckle includes a fixed base, the upper end of the fixed base is provided with a mounting seat capable of storing shoelaces, a wire take-up device capable of winding and rotating the shoelaces is installed inside the mounting seat, a fixed shell capable of driving the wire take-up to rotate is provided on the outer side of the wire take-up device, and a rotating upper cover capable of rebounding is clamped on the outer side of the fixed shell.

[0007] Preferably, the fixed base includes a notch, a groove S, a protrusion S, a buckle groove A and a buckle groove B, the notch is opened on the outer wall of the fixed base, the fixed base is fixedly installed on the shoe upper, shoelaces are inserted into the interior of the fixed base, the protrusion S is integrally connected to the upper surface of the fixed base, the groove S is opened inside the protrusion S, the number of the grooves S is two, the buckle groove A and the buckle groove B are opened at the bottom of the fixed base, and the buckle groove A and the buckle groove B are connected.

[0008] Preferably, the mounting seat includes a rack edge, a wire feed protrusion, a buckle B and a buckle A, the mounting seat is clamped inside the fixed base through the buckle B and the buckle A, the buckle B and the buckle A are integrally connected to the bottom of the mounting seat, the size of the buckle B is adapted to the size of the buckle slot B, the buckle B is clamped to the buckle slot B, the size of the buckle A is adapted to the size of the buckle slot A, the buckle A is clamped to the buckle slot A, the wire feed protrusion is integrally connected to the outer wall of the mounting seat, the number of the wire feed protrusions is two, the wire feed protrusion is installed inside the groove S, the rack edge is integrally connected to the inner wall of the mounting seat, the rack edge is meshed with the gear on the wire take-up device, so that when the wire take-up device rotates, the rack edge can drive the mounting seat to rotate together, thereby realizing the automatic winding and storage of the shoelaces. The rotating upper cover includes a cover body, a torsion spring and anti-slip patterns.

[0009] When in use, the user only needs to pass the shoelaces through the fixed base and the mounting seat, and then rotate the wire take-up device to achieve automatic winding and storage of the shoelaces.

[0010] Preferably, the wire take-up device includes a central cylinder, a convex tooth block and a wire entry hole, the wire take-up device is rotatably connected to the inside of the mounting seat, the central cylinder is fixedly connected to the top of the wire take-up device, the convex tooth block is integrally connected to the surface of the central cylinder, the number of the convex tooth blocks is two, the wire entry holes are opened on the outer wall of the wire take-up device and are arranged relatively, the wire entry holes are divided into two groups, each group has four holes, and through the setting of the wire entry holes, the bottom of the shoelaces can be fixed to the inside of the wire take-up device, which is convenient for winding up the shoelaces, and through the setting of the wire entry protrusions, the shoelaces can be wound up, which is convenient for use, and the number of the wire entry protrusions is only two, which can make it more convenient to wind up the shoelaces.

[0011] Preferably, the fixed shell includes an arc-shaped groove, a convex block, a center groove, a concave tooth block, a fixed card edge and an arc-shaped block. The fixed shell is clamped on the top of the wire take-up device through the center groove. The center groove is opened in the middle of the fixed shell. The size of the center groove is adapted to the size of the center cylinder. The center cylinder is arranged inside the center groove. The arc-shaped groove is opened on the surface of the fixed shell. The number of the arc-shaped grooves is three. The convex block is integrally connected to the outer wall of the fixed shell. The number of the convex block is three. The concave tooth block is integrally connected to On the inner wall of the arc-shaped groove, the concave tooth block is meshed with the convex tooth block, the fixed clamping edge is fixedly connected to the bottom of the inner wall of the fixed shell, the number of the fixed clamping edges is three, and the fixed clamping edge is clamped on the outer side of the mounting seat, the arc-shaped clamping block is integrally connected to one end of the concave tooth block, the arc-shaped clamping block is meshed with the rack edge, the shape of the arc-shaped clamping block is arc-shaped, and a rack is provided at the end. Several clamping teeth on the rack edge and the arc-shaped clamping block can cooperate to produce a precisely combined mechanical sound, which can not only improve the user's comfort, but also make it very convenient to reel in the shoelaces.

[0012] Preferably, the rotating upper cover includes an arc-shaped protrusion and a blocking groove, the rotating upper cover is clamped on the outer side of the fixed shell through the blocking groove, the blocking groove is opened on the inner wall of the rotating upper cover, the number of the blocking grooves is three, the arc-shaped protrusion is fixedly connected to the inner wall of the top of the rotating upper cover, the number of the arc-shaped protrusions is three, the arc-shaped protrusion is clamped inside the arc-shaped groove, and the size of the arc-shaped protrusion is adapted to the size of the arc-shaped groove.

[0013] Compared with the prior art, the beneficial effects of the utility model are:

[0014] The utility model realizes automatic winding and storage of shoelaces through ingenious structural design, greatly improving the convenience of putting on and taking off shoes. Users only need to simply operate the wire take-up device to easily complete the winding and fixing of shoelaces, without having to manually perform tedious shoelace tying steps, which saves time and effort and is convenient and quick.

[0015] The utility model adopts a close combination of multiple components such as a fixed base, a mounting base, a wire take-up device, a fixed shell and a rotating upper cover to ensure the stability and durability of the structure. The card connection and meshing design between the various components make the entire device smoother when rotating and operating, and less prone to malfunction or looseness.

[0016] The meshing connection between the concave tooth block and the convex tooth block not only increases the connection strength between the fixed shell and the take-up device, but also makes the rotation between the two smoother. This design not only ensures the stability of the device, but also increases its service life. The rack edge is located on the inner wall of the mounting seat and can cooperate with the corresponding gear structure to achieve precise rotation and positioning. This design not only improves the operating accuracy of the equipment, but also enhances its stability and durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0018] Figure 2 This is an explosion diagram of the utility model;

[0019] Figure 3 It is a structural schematic diagram of the mounting seat and the fixing shell of the utility model;

[0020] Figure 4 It is a three-dimensional diagram of the utility model.

[0021] In the figure: 1. fixed base; 2. mounting base; 3. wire take-up device; 4. fixed shell; 5. rotating upper cover; 11. notch; 12. groove S; 13. protrusion S; 14. buckle groove A; 15. buckle groove B; 21. rack edge; 22. wire inlet protrusion; 23. buckle B; 24. buckle A; 31. center cylinder; 32. convex tooth block; 33. wire inlet hole; 41. arc-shaped groove; 42. convex block; 43. center groove; 44. concave tooth block; 45. fixed clamping edge; 46. arc-shaped block; 51. arc-shaped protrusion; 52. block groove. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0023] See also Figure 1-4 A rotating elastic shoe buckle shown in the figure includes a fixed base 1, a mounting seat 2 for storing shoelaces is arranged on the upper end of the fixed base 1, a wire take-up device 3 for winding and rotating the shoelaces is installed inside the mounting seat 2, a fixed shell 4 for driving the wire take-up device 3 to rotate is arranged on the outer side of the wire take-up device 3, and a rotating upper cover 5 capable of rebounding is clamped on the outer side of the fixed shell 4.

[0024] The design of the rotating elastic shoe buckle is ingenious and practical. It is not only convenient for storing shoelaces, but also can adjust the tightness of shoelaces through simple operation. A precise gear structure is arranged inside the wire take-up device 3. By rotating the fixed shell 4, the gear inside the wire take-up device 3 can be driven to rotate, thereby winding and tightening the shoelaces. At the same time, the material of the wire take-up device 3 is selected from high-strength plastic, which not only ensures durability but also reduces the overall weight.

[0025] The rotating upper cover 5 is made of elastic material and has good resilience. Even if the child accidentally breaks it open, the rotating upper cover 5 will not be removed, but can rebound, which is very convenient. When the shoelaces need to be adjusted, just press the rotating upper cover 5 lightly to unlock the fixed shell 4, and then rotate the fixed shell 4 to adjust.

[0026] The design of this rotating elastic shoe buckle is not only convenient and practical, but also stylish and generous in appearance, and can be used with various styles of shoes. Whether it is sports shoes, casual shoes or leather shoes, it can show a unique personality and taste.

[0027] The fixed base 1 includes a notch 11, a groove S12, a protrusion S13, a buckle groove A14 and a buckle groove B15. The notch 11 is opened on the outer wall of the fixed base 1. The fixed base 1 is fixedly installed on the shoe upper. Shoelaces are inserted into the interior of the fixed base 1. The protrusion S13 is integrally connected to the upper surface of the fixed base 1. The groove S12 is opened inside the protrusion S13. There are two grooves S12. The buckle groove A14 and the buckle groove B15 are opened at the bottom of the fixed base 1. The buckle groove A14 and the buckle groove B15 are connected.

[0028] Specifically, the opening position of the notch 11 is carefully selected, which is convenient for user operation and can maintain the overall beauty of the fixed base 1. The size of the notch 11 is also accurately calculated to ensure that the shoelace can pass smoothly, while providing sufficient fixing force to prevent the shoelace from loosening.

[0029] The design of the protrusion S13 not only increases the stability of the fixed base 1, but also provides additional comfort for the user. It is integrally connected to the upper surface of the fixed base 1, ensuring the stability and durability of the structure. The connection design of the buckle groove A14 and the buckle groove B15 makes the structure easier to install and disassemble.

[0030] The mounting base 2 includes a rack edge 21, a wire inlet protrusion 22, a buckle B23 and a buckle A24. The mounting base 2 is clamped to the inside of the fixed base 1 by the buckle B23 and the buckle A24. The buckle B23 and the buckle A24 are integrally connected to the bottom of the mounting base 2. The size of the buckle B23 is compatible with the size of the buckle groove B15. The buckle B23 is clamped to the buckle groove B15. The size of the buckle A24 is compatible with the size of the buckle groove A14. The buckle A24 is clamped to the buckle groove A14. The wire inlet protrusion 22 is integrally connected to the outer wall of the mounting base 2. There are two wire inlet protrusions 22. The wire inlet protrusion 22 is installed in the inside of the groove S12. The rack edge 21 is integrally connected to the inner wall of the mounting base 2.

[0031] Specifically, the design of the mounting base 2 is unique and practical, and the clever combination of the rack edge 21, the wire inlet protrusion 22, the buckle B23 and the buckle A24 makes the entire installation process simple and stable. The rack edge 21 is located on the inner wall of the mounting base 2 and can cooperate with the corresponding gear structure to achieve precise rotation and positioning. This design not only improves the operating accuracy of the equipment, but also enhances its stability and durability.

[0032] The wire inlet protrusions 22 are another important part of the mounting base 2. They are integrally connected to the outer wall of the mounting base 2, and there are two of them. The design of the wire inlet protrusions 22 cleverly adapts to the shape of the groove S12, so that the mounting base 2 can be stably installed on the fixed base 1. This structure not only simplifies the installation process, but also improves the overall stability of the device.

[0033] Buckle B23 and buckle A24 are key parts of the mounting base 2. They are integrally connected to the bottom of the mounting base 2 and respectively match the buckle slot B15 and buckle slot A14 of the fixed base 1. The buckle design allows the mounting base 2 to be easily and quickly snapped into the inside of the fixed base 1 without the use of additional tools or screws. This design not only improves installation efficiency, but also makes the disassembly and maintenance of the equipment easier.

[0034] The wire take-up device 3 includes a central cylinder 31, a protruding tooth block 32 and a wire entry hole 33. The wire take-up device 3 is rotatably connected to the inside of the mounting base 2. The central cylinder 31 is fixedly connected to the top of the wire take-up device 3. The protruding tooth block 32 is integrally connected to the surface of the central cylinder 31. There are two protruding tooth blocks 32. The wire entry holes 33 are opened on the outer wall of the wire take-up device 3 and are arranged opposite to each other. The wire entry holes 33 are divided into two groups, and each group has four holes.

[0035] Specifically, the design of the wire take-up device 3 is exquisite and practical, which not only effectively solves the problem of shoelace storage, but also makes the entire device look neater and more beautiful. The central cylinder 31, as the core part of the wire take-up device 3, stably supports the entire structure and ensures the smooth rotation of the wire take-up device 3. The design of the convex tooth block 32 enhances the connection stability between the wire take-up device 3 and the mounting seat 2. At the same time, the number of the convex tooth blocks 32 is set to two, which not only ensures sufficient connection strength, but also avoids excessive complexity of the structure due to too many convex tooth blocks.

[0036] The fixed shell 4 includes an arc-shaped groove 41, a convex block 42, a central groove 43, a concave tooth block 44, a fixed card edge 45 and an arc-shaped block 46. The fixed shell 4 is clamped on the top of the wire take-up device 3 through the central groove 43. The central groove 43 is opened in the middle of the fixed shell 4. The size of the central groove 43 is adapted to the size of the central cylinder 31. The central cylinder 31 is arranged inside the central groove 43. The arc-shaped groove 41 is opened on the surface of the fixed shell 4. The number of the arc-shaped grooves 41 is three. The convex block 42 is integrally connected to On the outer wall of the fixed shell 4, there are three convex card blocks 42, the concave tooth block 44 is integrally connected to the inner wall of the arc-shaped groove 41, the concave tooth block 44 is meshed with the convex tooth block 32, and the fixed card edge 45 is fixedly connected to the bottom of the inner wall of the fixed shell 4. There are three fixed card edges 45, and the fixed card edge 45 is clamped on the outer side of the mounting seat 2. The arc card block 46 is integrally connected to one end of the concave tooth block 44, and the arc card block 46 is meshed with the rack edge 21. The shape of the arc card block 46 is arc-shaped, and a rack is provided at the end.

[0037] Specifically, the design of the fixed shell 4 is exquisite and practical, and the coordinated work of various components makes the entire device run stably and efficiently. The setting of the arc groove 41 not only enhances the structural strength of the fixed shell 4, but also facilitates the installation of other components. The presence of the convex block 42 allows the fixed shell 4 to be more firmly fixed on the top of the take-up device 3 to prevent shaking or falling off during use.

[0038] The close fit between the central groove 43 and the central cylinder 31 forms a stable connection between the wire take-up device 3 and the fixed shell 4. This design not only ensures the normal operation of the wire take-up device 3, but also makes the entire device more beautiful.

[0039] In particular, the meshing connection between the concave tooth block 44 and the convex tooth block 32 not only increases the connection strength between the fixed housing 4 and the wire take-up device 3, but also makes the rotation between the two smoother. This design not only ensures the stability of the device, but also increases its service life.

[0040] The meshing connection between the arc block 46 and the rack edge 21 allows the fixed shell 4 to rotate with the rotation of the mounting base 2, thereby realizing the retracting function of the wire take-up device 3. The shape of the arc block 46 and the rack design make it have good wear resistance and durability, and can work stably for a long time.

[0041] The rotating upper cover 5 includes an arc-shaped protrusion 51 and a clamping groove 52. The rotating upper cover 5 is clamped on the outer side of the fixed shell 4 through the clamping groove 52. The clamping groove 52 is opened on the inner wall of the rotating upper cover 5. The number of the clamping grooves 52 is three. The arc-shaped protrusion 51 is fixedly connected to the inner wall of the top of the rotating upper cover 5. The number of the arc-shaped protrusions 51 is three. The arc-shaped protrusion 51 is clamped inside the arc-shaped groove 41. The size of the arc-shaped protrusion 51 is adapted to the size of the arc-shaped groove 41.

[0042] The specific design of the rotating cover 5 is full of practicality and exquisiteness. The setting of the arc-shaped protrusion 51 not only makes the rotating cover 5 more stable when closed, but also provides an intuitive rotation direction indication for the user. The ingenious combination of the block groove 52 and the arc-shaped groove 41 further enhances the connection strength between the rotating cover 5 and the fixed shell 4, making the entire structure both stable and durable.

[0043] When the user needs to open or close the rotating upper cover 5, he only needs to gently rotate it, and the arc-shaped protrusion 51 will drive the arc-shaped groove 41 to rotate, and at the same time, the block groove 52 will also cooperate with the block on the outside of the fixed shell 4, so as to achieve a quick and stable connection. This design not only simplifies the operation process, but also improves the user experience of the product.

[0044] Working principle and process: When the device is needed, first ensure that the fixed base 1 is firmly installed in the desired position. Then, align the wire inlet protrusion 22 of the mounting base 2 with the groove S12 of the fixed base 1, and match the buckle B23 and the buckle A24 with the buckle groove B15 and the buckle groove A14 of the fixed base 1 to achieve rapid installation of the mounting base 2. The rack edge 21 of the mounting base 2 cooperates with the gear structure of the fixed base 1 to achieve precise rotation and positioning.

[0045] Once the mounting base 2 is installed, the wire take-up device 3 can start working. The rotating upper cover 5 can be easily opened or closed by cooperating the arc-shaped protrusion 51 of the rotating upper cover 5 with the arc-shaped groove 41 of the fixed shell 4. When the shoelaces need to be stored, the shoelaces are passed through the wire entry hole 33 of the wire take-up device 3, and the shoelaces are stored by rotating the wire take-up device 3. At this time, the meshing connection between the convex tooth block 32 and the concave tooth block 44 ensures the stable rotation of the wire take-up device 3.

[0046] During the rotation of the wire take-up device 3, the arc-shaped block 46 of the fixed housing 4 is meshed with the rack edge 21 of the mounting seat 2, so that the fixed housing 4 can rotate along with the rotation of the mounting seat 2. This design not only ensures the smooth rotation of the wire take-up device 3, but also makes the entire device more stable during the rotation process.

[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 rotating elastic shoe buckle, comprising a fixed base (1), characterized in that: The upper end of the fixed base (1) is provided with a mounting seat (2) capable of storing shoelaces, a wire take-up device (3) capable of winding and rotating the shoelaces is installed inside the mounting seat (2), a fixed shell (4) capable of driving the wire take-up device (3) to rotate is provided on the outer side of the wire take-up device (3), and a resilient rotating upper cover (5) is clamped on the outer side of the fixed shell (4).

2. The rotating elastic shoe buckle according to claim 1, characterized in that: The fixed base (1) comprises a notch (11), a groove S (12), a protrusion S (13), a buckle groove A (14) and a buckle groove B (15); the notch (11) is arranged on the outer wall of the fixed base (1); the fixed base (1) is fixedly mounted on the shoe upper; a shoelace is inserted into the interior of the fixed base (1); the protrusion S (13) is integrally connected to the upper surface of the fixed base (1); the groove S (12) is arranged inside the protrusion S (13); the number of the grooves S (12) is two; the buckle groove A (14) and the buckle groove B (15) are arranged at the bottom of the fixed base (1); the buckle groove A (14) and the buckle groove B (15) are connected.

3. The rotating elastic shoe buckle according to claim 1, characterized in that: The mounting seat (2) comprises a rack edge (21), a wire entry protrusion (22), a buckle B (23) and a buckle A (24); the mounting seat (2) is buckled inside the fixed base (1) via the buckle B (23) and the buckle A (24); the buckle B (23) and the buckle A (24) are integrally connected to the bottom of the mounting seat (2); the size of the buckle B (23) matches the size of the buckle groove B (15); the buckle B (23) and the buckle A (24) are connected to the mounting seat (2) in a fixed manner; The buckle groove B (15) is snap-connected, the size of the buckle A (24) is compatible with the size of the buckle groove A (14), the buckle A (24) is snap-connected with the buckle groove A (14), the line feed protrusion (22) is integrally connected to the outer wall of the mounting seat (2), the number of the line feed protrusions (22) is two, the line feed protrusions (22) are installed inside the groove S (12), and the rack edge (21) is integrally connected to the inner wall of the mounting seat (2).

4. The rotating elastic shoe buckle according to claim 1, characterized in that: The wire take-up device (3) comprises a central cylinder (31), a convex tooth block (32) and a wire entry hole (33); the wire take-up device (3) is rotatably connected to the inside of the mounting base (2); the central cylinder (31) is fixedly connected to the top of the wire take-up device (3); the convex tooth block (32) is integrally connected to the surface of the central cylinder (31); the number of the convex tooth blocks (32) is two; the wire entry holes (33) are opened on the outer wall of the wire take-up device (3) and are arranged opposite to each other; the wire entry holes (33) are in two groups, each group having four holes.

5. The rotating elastic shoe buckle according to claim 1, characterized in that: The fixed shell (4) comprises an arc-shaped groove (41), a convex block (42), a central groove (43), a concave tooth block (44), a fixed clamping edge (45) and an arc-shaped block (46); the fixed shell (4) is clamped on the top of the wire take-up device (3) through the central groove (43); the central groove (43) is provided in the middle of the fixed shell (4); the size of the central groove (43) matches the size of the central cylinder (31); the central cylinder (31) is arranged inside the central groove (43); the arc-shaped groove (41) is provided on the surface of the fixed shell (4); the number of the arc-shaped grooves (41) is three; the convex block (42) is integrated The fixed housing (4) is connected to the outer wall of the fixed housing (4), the number of the convex clamping blocks (42) is three, the concave tooth block (44) is integrally connected to the inner wall of the arc-shaped groove (41), the concave tooth block (44) is meshedly connected with the convex tooth block (32), the fixed clamping edge (45) is fixedly connected to the bottom of the inner wall of the fixed housing (4), the number of the fixed clamping edges (45) is three, the fixed clamping edge (45) is clamped on the outer side of the mounting seat (2), the arc-shaped clamping block (46) is integrally connected to one end of the concave tooth block (44), the arc-shaped clamping block (46) is meshedly connected with the rack edge (21), the arc-shaped clamping block (46) is in an arc shape, and a rack is provided at the end.

6. The rotating elastic shoe buckle according to claim 1, characterized in that: The rotating upper cover (5) comprises an arc-shaped protrusion (51) and a clamping groove (52); the rotating upper cover (5) is clamped on the outer side of the fixed shell (4) through the clamping groove (52); the clamping groove (52) is arranged on the inner wall of the rotating upper cover (5); the number of the clamping grooves (52) is three; the arc-shaped protrusion (51) is fixedly connected to the inner wall of the top of the rotating upper cover (5); the number of the arc-shaped protrusion (51) is three; the arc-shaped protrusion (51) is clamped inside the arc-shaped groove (41); the size of the arc-shaped protrusion (51) is adapted to the size of the arc-shaped groove (41).

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