Locking mechanism and protection pressing plate easy to open and close

Abstract

The utility model discloses a locking mechanism and a protection pressing plate easy to open and close, and relates to the technical field of relay protection, and the locking mechanism comprises an anti-falling unit which comprises a buffer cylinder, a damping rod and a damping spring; the connecting unit comprises a connecting cylinder, a switch assembly and a clamping assembly; the pressing plate unit comprises a base assembly and a pressing plate assembly arranged at the upper end of the base assembly. The beneficial effects of the utility model are that the rapid connection of the relay protection system is realized through the clamping assembly, the rapid disconnection of the relay protection system can be realized through the switch assembly, and after connection, the buffer cylinder can buffer the vibration of the connecting cylinder, thereby reducing the influence of the vibration on the equipment, ensuring the stability of the equipment, and improving the reliability of the equipment. The situation of poor connection or looseness is avoided, the connection state is adjusted by rotating the connection plate, positioning is conducted through attraction of the fixed magnetic ring and the connection magnetic ring, the operation process is simplified, and efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of relay protection, in particular to a locking mechanism and a protection pressing plate which is easy to open and close. Background Art

[0002] The protection pressure plate is also called the protection connection plate or the trip pressure plate. It is the bridge and link between the protection device and the external wiring, which is related to whether the protection function and the action output can function normally. The protection pressure plate is a disconnection point visible to the naked eye, which is convenient for the operator to judge whether the trip circuit of the relay protection device can be connected to the trip coil of the switch (circuit breaker), which provides great convenience for maintenance and operation.

[0003] At present, the common protection pressure plate is fixed by the connection plate knob, which takes a long time to install and remove, and has low efficiency. In the machine room environment, the equipment will generate uninterrupted vibration during operation, which will lead to poor connection or looseness in the long run. In addition, under high load or frequent operation, the pressure plate is prone to aging, damage or even failure. Therefore, a protection pressure plate that can achieve fast connection and removal and has low loss during use is needed to ensure the stability of the relay protection system.

[0004] In view of the above problems, a locking mechanism and a protective pressure plate that is easy to open and close are proposed to solve the above problems. Utility Model Content

[0005] Some simplifications or omissions may be made in this section and the abstract of the specification and the title of the utility model of this application to avoid blurring the purpose of this section, the abstract of the specification and the title of the utility model, and such simplifications or omissions shall not be used to limit the scope of the utility model.

[0006] In view of the above-mentioned prior art problems, the present utility model is proposed.

[0007] The utility model aims to provide a locking mechanism, which aims to solve the problem that vibration during the operation of equipment affects the stability of the system.

[0008] In order to solve the above technical problems, the utility model provides the following technical solutions: a locking mechanism, which includes an anti-drop unit, including a buffer cylinder, a damping rod is arranged inside the buffer cylinder, and the damping rod is connected to the buffer cylinder through a damping spring;

[0009] The connecting unit comprises a connecting cylinder, wherein a switch assembly is arranged at the upper end of the connecting cylinder and a clamping assembly is arranged at the lower end, and the damping rod and the connecting cylinder are matched through the clamping assembly.

[0010] As a preferred solution of the locking mechanism of the utility model, the upper end of the buffer cylinder is a connecting groove, and the lower end is a damping groove, which are connected through a sliding hole, and the damping groove is filled with damping medium.

[0011] As a preferred solution of the locking mechanism of the utility model, wherein: the upper end of the damping rod is a connecting block, and the lower end is a piston block, the connecting block is arranged in the connecting groove, the piston block is arranged in the damping groove, and the damping rod cooperates with the sliding hole.

[0012] As a preferred solution of the locking mechanism of the utility model, wherein: a snap-fit ​​groove is provided at the upper end of the connecting block, the snap-fit ​​groove is arranged along the circumference of the connecting block, and its cross-section is an inverted triangle, and the piston block is evenly provided with multiple guide holes along the circumferential direction, which pass through the upper and lower ends of the piston block.

[0013] As a preferred solution of the locking mechanism of the utility model, the connecting cylinder is a cylinder with a closed lower end, and its lower end extends into the buffer cylinder and cooperates with the damping rod. A movable groove is opened at the upper end of the connecting cylinder, and block through holes are opened symmetrically on both sides of the lower end.

[0014] As a preferred solution of the locking mechanism of the utility model, wherein: the switch assembly includes a switch connecting rod, and a switch spring connecting the connecting tube and the switch connecting rod, the switch connecting rod is a hollow cylinder, the upper end of which extends out of the connecting tube to form a pressing block, the lower end of the pressing block is a limit plate, which is arranged in the movable groove, the lower end of the switch spring is fixed to the lower end of the movable groove, and the upper end is connected to the limit plate.

[0015] As a preferred solution of the locking mechanism of the utility model, wherein: the engaging assembly includes a card block, which is arranged in the card block through hole and corresponds one to one to the card block through hole, the card blocks are connected by a card block spring, the front end of the card block is a triangular inclined block, which cooperates with the engaging groove, and the rear end of the card block is an adjusting inclined block, which cooperates with the switch connecting rod.

[0016] The beneficial effects of the locking mechanism of the utility model are: the relay protection system can be quickly connected through the snap-fit ​​assembly, and the relay protection system can be quickly disconnected through the switch assembly. At the same time, after the connection, the buffer cylinder can buffer the vibration of the connecting cylinder, reduce the impact of the vibration on the equipment, ensure the stability of the equipment, and avoid the occurrence of poor connection or looseness.

[0017] Another object of the utility model is to provide a protective pressure plate that is easy to open and close, so as to solve the problem that the connection and disassembly operations of the traditional protective pressure plate are relatively complicated.

[0018] To solve the above technical problems, the utility model also provides the following technical solutions: a protective pressure plate that is easy to open and close, which includes a locking mechanism; and a pressure plate unit, including a base assembly and a pressure plate assembly arranged on the upper end of the base assembly.

[0019] As a preferred solution of the protective pressure plate that is easy to open and close of the utility model, the base assembly includes a fixed base, a fixed nut, a wire spring socket and a fixed magnetic ring. Fixed cylinders are provided at both ends of the lower side of the fixed base, which cooperate with the fixed nut. The wire spring socket is provided in the fixed cylinder. Fixed blocks are respectively extended on both sides of the fixed base, and opening and closing plug holes are provided on them. The fixed magnetic ring is provided at the upper end of the fixed base, and the buffer cylinder is fixedly provided at the lower end of the fixed base.

[0020] As a preferred solution of the protective pressure plate that is easy to open and close of the utility model, the pressure plate assembly includes a rotating connecting plate, a protective shell arranged on the upper end of the rotating connecting plate, and a connecting magnetic ring arranged at the lower end of the rotating connecting plate. Connecting columns are respectively arranged on both sides of the lower end of the rotating connecting plate, which respectively extend into the fixed tube and cooperate with the wire spring socket, the connecting magnetic ring cooperates with the fixed magnetic ring, and the connecting tube is fixedly arranged at the center position of the lower end of the rotating connecting plate.

[0021] The utility model has the beneficial effects of the easily opened and closed protective pressure plate: the connection state is adjusted by rotating the connecting plate, and positioning is performed by the attraction of the fixed magnetic ring and the connecting magnetic ring, thereby simplifying the operation process and improving efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the following briefly introduces the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0023] Figure 1 It is an overall schematic diagram of the protective pressure plate that is easy to open and close in the utility model.

[0024] Figure 2 It is an exploded schematic diagram of the protective pressure plate that is easy to open and close in the utility model.

[0025] Figure 3 It is a cross-sectional schematic diagram of the easily opened and closed protective pressure plate in the utility model.

[0026] Figure 4 For the utility model Figure 3 A partial enlarged view of A in the middle (i.e., a schematic diagram of the anti-falling unit).

[0027] Figure 5 For the utility model Figure 3 A partial enlarged view of B (i.e., a schematic diagram of the connection unit). DETAILED DESCRIPTION

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0029] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0030] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or selective embodiment that is mutually exclusive with other embodiments.

[0031] Example 1

[0032] Reference Figure 3-4 , which is the first embodiment of the utility model, and this embodiment provides a locking mechanism, including an anti-drop unit 100, including a buffer cylinder 101, and a damping rod 102 is arranged inside the buffer cylinder 101;

[0033] The connecting unit 200 includes a connecting tube 201 . A switch assembly 202 is disposed at the upper end of the connecting tube 201 , and a clamping assembly 203 is disposed at the lower end. The damping rod 102 and the connecting tube 201 are matched with each other through the clamping assembly 203 .

[0034] Furthermore, the upper end of the buffer cylinder 101 is a connecting groove 101a, and the lower end is a damping groove 101b, which are connected by a sliding hole 101c. The inner diameter of the sliding hole 101c is smaller than the connecting groove 101a and the damping groove 101b, and the damping groove 101b is filled with damping medium.

[0035] Furthermore, the damping rod 102 is dumbbell-shaped, with larger diameters at both ends. The upper end is a connecting block 102a, and the lower end is a piston block 102b. The connecting block 102a is arranged in the connecting groove 101a, and the piston block 102b is arranged in the damping groove 101b. The damping rod 102 cooperates with the sliding hole 101c, and the damping spring 103 is wound around the damping rod 102 and the lower end is fixed to the lower side wall of the connecting groove 101a, and the upper end is fixedly connected to the connecting block 102a.

[0036] It should be noted that the diameter of the damping rod 102 is consistent with that of the sliding hole 101c, and sealing measures are taken, such as providing a sealing gasket, so that the damping groove 101b is a closed space.

[0037] Furthermore, a snap-fit ​​groove 102a-1 is provided at the upper end of the connecting block 102a. The snap-fit ​​groove 102a-1 is cylindrical and arranged along the circumference of the connecting block 102a. Its cross-section is an inverted frustum. The piston block 102b is evenly provided with a plurality of cylindrical guide holes 102b-1 along the circumferential direction, which penetrate the upper and lower ends of the piston block 102b.

[0038] Furthermore, the connecting tube 201 is a cylinder with a closed lower end, whose lower end extends into the buffer tube 101 and cooperates with the damping rod 102. A movable groove 201a is opened at the upper end of the connecting tube 201, and block through holes 201b are opened symmetrically on both sides of the lower end.

[0039] It should be noted that, in the initial state, under the action of the damping spring 103, the piston block 102b maintains a certain distance from the upper and lower ends of the damping groove 101b, that is, the piston block 102b can vibrate up and down along the damping groove 101b.

[0040] During use, when the equipment generates vibration, the damping rod 102 is driven to vibrate up and down along the sliding hole 101c. At this time, the damping medium in the damping groove 101b flows through the guide hole 102b-1 to absorb the vibration energy, and the damping spring 103 resets the damping rod 102 to achieve the vibration reduction effect.

[0041] In summary, the vibration of the connecting tube 201 is buffered by the buffer tube 101, thereby reducing the impact of the vibration on the equipment, enhancing the stability of the equipment operation, and avoiding the occurrence of poor connection or looseness.

[0042] Example 2

[0043] Reference Figure 3 to Figure 5 , which is the second embodiment of the utility model, based on the previous embodiment, this embodiment provides a locking mechanism, including an anti-falling unit 100, including a buffer cylinder 101;

[0044] The connecting unit 200 includes a connecting tube 201 . A switch assembly 202 is disposed at the upper end of the connecting tube 201 , and a clamping assembly 203 is disposed at the lower end. The damping rod 102 and the connecting tube 201 are matched with each other through the clamping assembly 203 .

[0045] Furthermore, the upper end of the buffer cylinder 101 is a connecting groove 101a, and the lower end is a damping groove 101b, which are connected through a sliding hole 101c, and the damping groove 101b is filled with damping medium.

[0046] Furthermore, the damping rod 102 is dumbbell-shaped, with larger diameters at both ends. The upper end is a connecting block 102a, and the lower end is a piston block 102b. The connecting block 102a is arranged in the connecting groove 101a, and the piston block 102b is arranged in the damping groove 101b. The damping rod 102 cooperates with the sliding hole 101c, and the damping spring 103 is wound around the damping rod 102 and the lower end is fixed to the lower side wall of the connecting groove 101a, and the upper end is fixedly connected to the connecting block 102a.

[0047] Furthermore, a snap-fit ​​groove 102a-1 is provided at the upper end of the connecting block 102a, and the snap-fit ​​groove 102a-1 is arranged along the circumference of the connecting block 102a, and its cross-section is an inverted triangle. The piston block 102b is evenly provided with a plurality of guide holes 102b-1 along the circumferential direction, which penetrate the upper and lower ends of the piston block 102b.

[0048] Furthermore, the connecting tube 201 is a cylinder with a closed lower end, whose lower end extends into the buffer tube 101 and cooperates with the damping rod 102. A movable groove 201a is opened at the upper end of the connecting tube 201, and block through holes 201b are opened symmetrically on both sides of the lower end.

[0049] Furthermore, the switch assembly 202 includes a switch connecting rod 202a and a switch spring 202b. The switch connecting rod 202a is a hollow cylinder whose outer diameter is consistent with the inner diameter of the connecting cylinder 201. The upper end thereof extending out of the connecting cylinder 201 is a pressing block 202a-1. The lower end of the pressing block 202a-1 is a limiting plate 202a-2, which is arranged in the movable groove 201a. The switch spring 202b is wound around the outside of the switch connecting rod 202a and its lower end is fixed to the lower end of the movable groove 201a, and the upper end is fixedly connected to the limiting plate 202a-2.

[0050] Furthermore, the locking assembly 203 includes a locking block 203a, which is arranged in the locking block through hole 201b and corresponds one to one with the locking block through hole 201b. The locking blocks 203a are connected by a locking block spring 203b. The front end of the locking block 203a is a triangular inclined block 203a-1, whose cross-sectional shape is consistent with the side shape of the locking groove 102a-1 and is embedded in the locking groove 102a-1. The rear end of the locking block 203a is an adjusting inclined block 203a-2, which cooperates with the switch connecting rod 202a.

[0051] It should be noted that the block spring 203b is always in a compressed state, the height of the triangular inclined block 203a-1 is consistent with the height of the block through hole 201b, the adjusting inclined block 203a-2 is a right triangle with the hypotenuse facing outward, and when engaged with the engaging groove 102a-1, the upper end of the adjusting inclined block 203a-2 can slide into the switch connecting rod 202a under the action of external force, that is, the maximum distance between the outer sides of the top ends of each adjusting inclined block 203a-2 is not greater than the inner diameter of the switch connecting rod 202a.

[0052] When in use, the connecting tube 201 is pressed. When the triangular inclined surface block 203a-1 begins to contact the engaging groove 102a-1, the triangular inclined surface block 203a-1 is subjected to the extrusion force, compressing the block spring 203b, causing it to retract into the connecting tube 201. Continue to press. When the block 203a completely enters the engaging groove 102a-1, under the action of the block spring 203b, the block 203a cooperates with the engaging groove 102a-1 to complete the connection between the connecting tube 201 and the damping rod 102. When disassembly is required, press the switch connecting rod 202a to squeeze the adjusting inclined surface block 203a-2 inward and retract it into the connecting tube 201. While pressing the switch connecting rod 202a, pull up the connecting tube 201 to disengage it from the damping rod 102 to complete the disassembly.

[0053] In summary, the fast connection of the relay protection system can be achieved through the locking assembly 203, and the fast disconnection of the relay protection system can be achieved through the switch assembly 202, which simplifies the operation steps and improves the connection efficiency.

[0054] Example 3

[0055] Reference Figure 1-2 , which is the third embodiment of the utility model, based on the above embodiment, this embodiment further provides a protective pressure plate that is easy to open and close. It includes a pressure plate unit 300, including a base assembly 301, and a pressure plate assembly 302 arranged on the upper end of the base assembly 301.

[0056] Furthermore, the base assembly 301 includes a fixed base 301a, a fixing nut 301b, a wire spring socket 301c and a fixed magnetic ring 301d. Fixed cylinders 301a-1 are provided at both ends of the lower side of the fixed base 301a, which cooperate with the fixing nut 301b. The wire spring socket 301c is provided in the fixed cylinder 301a-1. Fixed blocks 301a-2 are respectively extended on both sides of the fixed base 301a, and opening and closing plug holes 301a-3 are provided on them. The fixed magnetic ring 301d is provided at the upper end of the fixed base 301a, and the buffer cylinder 101 is fixedly provided at the lower end of the fixed base 301a.

[0057] It should be noted that the fixing tube 301 a - 1 and the opening and closing plug hole 301 a - 3 are arranged on the same circumference with the buffer tube 101 as the center.

[0058] Furthermore, the pressure plate assembly 302 includes a rotating connecting plate 302a, a protective shell 302b arranged at the upper end of the rotating connecting plate 302a, and a connecting magnetic ring 302c arranged at the lower end of the rotating connecting plate 302a. Connecting columns 302a-1 are respectively arranged on both sides of the lower end of the rotating connecting plate 302a, which respectively extend into the fixed tube 301a-1 and cooperate with the wire spring socket 301c, the connecting magnetic ring 302c cooperates with the fixed magnetic ring 301d, and the connecting tube 201 is fixedly arranged at the center position of the lower end of the rotating connecting plate 302a.

[0059] During use, when in the disconnected state, the connecting column 302a-1 is located in the opening and closing plug hole 301a-3. When the line needs to be closed, the connecting plate 302a is rotated to insert the connecting column 302a-1 into the fixed tube 301a-1 and cooperate with the wire spring plug hole 301c. At this time, the fixed magnetic ring 301d and the connecting magnetic ring 302c attract each other to lock the state and complete the connection.

[0060] Importantly, it should be noted that the construction and arrangement of the present application shown in a plurality of different exemplary embodiments are only exemplary. Although only a few embodiments are described in detail in this disclosure, it should be readily understood by those who refer to this disclosure that many modifications are possible (e.g., the size, scale, structure, shape and ratio of various elements, and parameter values ​​(e.g., temperature, pressure, etc.), installation arrangements, use of materials, color, directional changes, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in the application. For example, the element shown as integrally formed can be composed of multiple parts or elements, the position of the element can be inverted or otherwise changed, and the nature or number or position of the discrete element can be changed or changed. Therefore, all such modifications are intended to be included in the scope of the present utility model. The order or sequence of any process or method steps can be changed or reordered according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure described herein that performs the function, and is not only structurally equivalent but also an equivalent structure. Without departing from the scope of the present invention, other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments. Therefore, the present invention is not limited to a specific embodiment, but extends to various modifications that still fall within the scope of the appended claims.

[0061] Additionally, in order to provide a concise description of example embodiments, all features of an actual embodiment (ie, those features that are not relevant to the best mode presently contemplated for carrying out the invention or those that are not relevant to implementing the invention) may not be described.

[0062] It will be appreciated that in the development of any actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but will be a routine task of design, fabrication, and production for those of ordinary skill having the benefit of this disclosure without undue experimentation.

[0063] It should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. A locking mechanism, characterized in that: include, An anti-falling unit (100) comprises a buffer cylinder (101), a damping rod (102) is arranged inside the buffer cylinder (101), and the damping rod (102) is connected to the buffer cylinder (101) via a damping spring (103); The connection unit (200) comprises a connection cylinder (201), wherein a switch assembly (202) is arranged at the upper end inside the connection cylinder (201) and a snap-fit ​​assembly (203) is arranged at the lower end thereof, and the damping rod (102) and the connection cylinder (201) are matched with each other through the snap-fit ​​assembly (203).

2. The locking mechanism according to claim 1, characterized in that: The upper end of the buffer cylinder (101) is a connecting groove (101a), and the lower end is a damping groove (101b), which are connected via a sliding hole (101c), and the damping groove (101b) is filled with damping medium.

3. The locking mechanism according to claim 2, characterized in that: The upper end of the damping rod (102) is a connecting block (102a), and the lower end is a piston block (102b); the connecting block (102a) is arranged in the connecting groove (101a), the piston block (102b) is arranged in the damping groove (101b), and the damping rod (102) cooperates with the sliding hole (101c).

4. The locking mechanism according to claim 3, characterized in that: The upper end of the connecting block (102a) is provided with a snap-fit ​​groove (102a-1), which is arranged along the circumference of the connecting block (102a) and has an inverted triangle cross section. The piston block (102b) is evenly provided with a plurality of guide holes (102b-1) along the circumferential direction, which penetrate the upper and lower ends of the piston block (102b).

5. The locking mechanism according to claim 4, characterized in that: The connecting cylinder (201) is a cylinder with a closed lower end, the lower end of which extends into the buffer cylinder (101) and cooperates with the damping rod (102). The upper end of the connecting cylinder (201) is provided with a movable groove (201a), and the lower end is symmetrically provided with block through holes (201b).

6. The locking mechanism according to claim 5, characterized in that: The switch assembly (202) comprises a switch connecting rod (202a) and a switch spring (202b) connecting the connecting tube (201) and the switch connecting rod (202a); the switch connecting rod (202a) is a hollow cylinder, the upper end of which protrudes from the connecting tube (201) to form a pressing block (202a-1); the lower end of the pressing block (202a-1) is a limiting plate (202a-2) which is arranged in the movable groove (201a); the lower end of the switch spring (202b) is fixed to the lower end of the movable groove (201a), and the upper end is connected to the limiting plate (202a-2).

7. The locking mechanism according to claim 6, characterized in that: The engaging assembly (203) comprises a engaging block (203a) which is arranged in the engaging block through hole (201b) and corresponds one to one with the engaging block through hole (201b); the engaging blocks (203a) are connected via engaging block springs (203b); the front end of the engaging block (203a) is a triangular inclined surface block (203a-1) which cooperates with the engaging groove (102a-1); the rear end of the engaging block (203a) is an adjusting inclined surface block (203a-2) which cooperates with the switch connecting rod (202a).

8. A protective pressure plate that is easy to open and close, characterized in that: It comprises a locking mechanism as claimed in any one of claims 1 to 7; and a pressure plate unit (300) comprising a base assembly (301) and a pressure plate assembly (302) arranged on the upper end of the base assembly (301).

9. The easily openable and closable protective pressure plate according to claim 8, characterized in that: The base assembly (301) comprises a fixed base (301a), a fixed nut (301b), a wire spring jack (301c) and a fixed magnetic ring (301d); fixed cylinders (301a-1) are arranged at both ends of the lower side of the fixed base (301a) and cooperate with the fixed nut (301b); the wire spring jack (301c) is arranged in the fixed cylinder (301a-1); fixed blocks (301a-2) are respectively extended from both sides of the fixed base (301a) and are provided with opening and closing plug holes (301a-3); the fixed magnetic ring (301d) is arranged at the upper end of the fixed base (301a); and the buffer cylinder (101) is fixedly arranged at the lower end of the fixed base (301a).

10. The easily openable and closable protective pressure plate according to claim 9, characterized in that: The pressure plate assembly (302) comprises a rotating connecting plate (302a), a protective shell (302b) arranged at the upper end of the rotating connecting plate (302a), and a connecting magnetic ring (302c) arranged at the lower end of the rotating connecting plate (302a); connecting columns (302a-1) are respectively arranged on both sides of the lower end of the rotating connecting plate (302a), which respectively extend into the fixed cylinder (301a-1) and cooperate with the wire spring jack (301c); the connecting magnetic ring (302c) cooperates with the fixed magnetic ring (301d); and the connecting cylinder (201) is fixedly arranged at the center position of the lower end of the rotating connecting plate (302a).

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