Portable electro-therapeutic apparatus

Abstract

The utility model belongs to the technical field of physiotherapy equipment, and discloses a portable electro-therapeutic apparatus. The connector comprises a shell, a circuit board, a connector assembly and a fixing assembly. The circuit board is arranged in a cavity formed by the shell, one end of the circuit board is electrically connected with the connector assembly, the connector assembly comprises at least two connectors, the fixing assembly is fixed at one end of the shell, and the first fixing piece and the second fixing piece are matched to clamp and fix the at least two connectors arranged at one end of the circuit board. The portable electro-therapeutic apparatus is provided with at least two connectors which are used as output channels and can be respectively connected with the electrode plates with the number twice that of the connectors, so that more electrode plates can be used for electro-therapy at the same time, and the electro-therapy efficiency is improved; in addition, loosening and shaking of the connector caused by repeated plugging and unplugging during dismounting of the electrode plates can be avoided, external force during plugging and unplugging is shared by at least two connectors and the fixing assembly together, and the situation that the connector is driven to shake when the external force is concentrated on one connector is prevented.

Description

Technical Field

[0001] The utility model relates to the technical field of physiotherapy equipment, in particular to a portable electrotherapy instrument. Background Art

[0002] An electrotherapy instrument is a physiotherapy device that connects a pulsed electrical signal of a certain voltage and frequency to the human body through an electrode to stimulate the human body. Since many components of human tissues have certain electrical properties, when subjected to appropriate electrical stimulation, the muscles, nerves, body fluids, blood, etc. of the human body will all produce certain physical and chemical reactions. Therefore, an electrotherapy instrument can be used to promote blood circulation in the human body, improve the body's immunity, and achieve the purpose of strengthening the body, preventing diseases, and assisting in treatment.

[0003] Most of the existing electrotherapy instruments are single-channel electrotherapy instruments, that is, they have only one output interface. A single output interface can only correspond to two electrode patches, one electrode patch is the positive electrode, and the other is the negative electrode so that the current can enter the human body. Therefore, a single-channel electrotherapy instrument can only perform electrotherapy on two parts of the user at the same time, and the electrotherapy efficiency is low. In addition, even if there are multi-channel electrotherapy instruments, because they have increased output interfaces, more plugging and unplugging operations are required when disassembling and assembling the electrode patches. Under multiple plugging and unplugging operations, it is easier for the output interface to become loose, affecting the overall service life of the electrotherapy instrument. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a portable electrotherapy instrument to improve the efficiency during electrotherapy and ensure the structural stability at the connector during long-term use.

[0005] To achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A portable electrotherapy instrument, comprising:

[0007] A housing, within which a cavity is formed;

[0008] A circuit board, which is arranged in the cavity and fixed to the housing;

[0009] A connector assembly, electrically connected to one end of the circuit board. The connector assembly includes at least two connectors, and the housing is provided with a first avoidance hole corresponding to the connector assembly;

[0010] A fixing assembly, fixed to one end of the housing. The fixing assembly includes a first fixing member and a second fixing member, and the first fixing member and the second fixing member cooperate to clamp at least two of the connectors between the first fixing member and the second fixing member.

[0011] Preferably, a first mounting groove is provided on a side of the first fixing member close to the connector assembly, and a second mounting groove is provided on a side of the second fixing member close to the connector assembly. The first mounting groove and the second mounting groove cooperate to form at least two mounting positions, and at least two of the connectors are fixedly mounted in the at least two mounting positions in a one-to-one correspondence.

[0012] Preferably, at least two of the connectors are spaced apart along an extending direction of one end of the circuit board.

[0013] Preferably, at least two of the connectors are spaced apart along a direction perpendicular to the extending direction of one end of the circuit board.

[0014] Preferably, the housing includes a first housing and a second housing, and the first housing and the second housing enclose to form the cavity; the first housing and the second housing are fixedly connected by snap connection. A plurality of snap protrusions are provided along a circumference of the first housing, and a plurality of snap grooves that can be correspondingly and cooperatively snap-connected with the snap protrusions are provided along a circumference of the second housing.

[0015] Preferably, the portable electrotherapy device further includes a power supply assembly. A power supply mounting position for mounting the power supply assembly is provided on the second housing, and the power supply assembly is electrically connected to the circuit board.

[0016] Preferably, a limiting groove is provided at one end of the second housing, and the fixing assembly is disposed in the limiting groove.

[0017] Preferably, a key assembly and a display assembly are electrically connected to a side of the circuit board close to the first housing.

[0018] Preferably, the portable electrotherapy device further includes a cover plate. The cover plate is covered on a side of the first housing away from the second housing. A key limiting member and a lens are provided on the cover plate. The key limiting member is provided corresponding to the key assembly, and the lens is provided corresponding to the display assembly.

[0019] Preferably, the portable electrotherapy device further includes a protective cover. The protective cover covers the first housing and the second housing from a side away from the cover plate; a second avoidance hole is provided on the protective cover corresponding to the first avoidance hole, and a fixing ring is provided on a side of the protective cover away from the cover plate.

[0020] Beneficial effects: The portable electrotherapy device provided by the present utility model includes a housing, a circuit board, a connector assembly, and a fixing assembly. The circuit board is disposed in a cavity formed by the housing and is electrically connected to the connector assembly at one end of the circuit board. The connector assembly includes at least two connectors. The at least two connectors can be used as output channels to respectively connect electrode patches with a number twice that of the connectors. Therefore, the portable electrotherapy device can simultaneously use multiple electrode patches for electrotherapy, increasing the efficiency of electrotherapy. In addition, the first fixing member and the second fixing member cooperate to simultaneously clamp and fix at least two connectors disposed at one end of the circuit board, avoiding loosening and shaking of the connectors caused by multiple plugging and unplugging of the electrode patches. At the same time, the external force during plugging and unplugging can be shared by at least two connectors and the fixing assembly, preventing the external force from concentrating on one connector and causing the connector to shake. Description of the Drawings

[0021] Figure 1 is an exploded view of the portable electrotherapy device provided by the present utility model;

[0022] Figure 2 is an overall schematic diagram of the portable electrotherapy device provided by the present utility model;

[0023] Figure 3 is a cross-sectional view of the portable electrotherapy device provided by the present utility model;

[0024] Figure 4 is a schematic diagram of one side of the cover plate of the portable electrotherapy device provided by the present utility model;

[0025] Figure 5 is a schematic diagram of the electrode patch assembly of the portable electrotherapy device provided by the present utility model;

[0026] Figure 6 is a schematic diagram of the side with the hanging rope hole of the portable electrotherapy device provided by the present utility model.

[0027] In the figure: 1 - Portable electrotherapy device main body; 2 - Cover plate; 3 - First housing; 4 - Button limiting member; 5 - Up adjustment button; 6 - Down adjustment button; 7 - Selection button; 8 - Switch button; 9 - Lens; 10 - First connector; 11 - Second connector; 12 - Second housing; 13 - Hanging rope hole; 14 - Screen; 15 - Screen bracket; 16 - Screen bracket connecting member; 17 - Circuit board; 18 - Battery connection socket; 19 - Battery wire; 20 - Power supply installation position; 21 - Battery; 22 - Hexagonal stud; 23 - Button board; 24 - Screw; 25 - Second fixing member; 26 - First fixing member; 27 - Button lining; 28 - Type-c interface rubber plug; 29 - Type-c interface; 30 - Clamping groove; 31 - Protective cover; 32 - Fixed ring; 33 - Output wire; 34 - Connection end; 35 - Electrode patch connection part; 36 - Second avoidance hole. Detailed Embodiments

[0028] The present utility model will be further described in detail below in conjunction with the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only for explaining the present utility model, rather than limiting the present utility model. In addition, it should be noted that for the sake of description, only the parts related to the present utility model rather than all the structures are shown in the drawings.

[0029] In the description of the present utility model, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0030] In the present utility model, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "above and to the right of", and "on the upper surface of" the second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is at a higher horizontal height than the second feature. The first feature being "below", "below and to the left of", and "on the lower surface of" the second feature includes that the first feature is directly below and obliquely below the second feature, or simply means that the first feature is at a lower horizontal height than the second feature.

[0031] In the description of this embodiment, the orientation or positional relationships such as "upper", "lower", "right", etc. are based on the orientation or positional relationships shown in the drawings. It is only for the convenience of description and simplifying the operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meanings.

[0032] Such as Figures 1-6As shown in the figure, this embodiment provides a portable electrotherapy device, which includes a housing, a circuit board 17, a connector assembly, and a fixing assembly. A cavity is formed inside the housing, and the cavity is used to accommodate the electrical appliances required by the portable electrotherapy device. Specifically, the circuit board 17 is arranged inside the cavity and fixed to the housing. One end of the circuit board 17 is electrically connected to the connector assembly. The connector assembly includes at least two connectors. Specifically, the connector assembly is the output end of the electrical signal generated by the circuit board 17 and is used to connect the output line of the electrode patch. The housing is provided with a first avoidance hole corresponding to the connector assembly, and the output line of the electrode patch is connected to the connector through the first avoidance hole. The fixing assembly is fixed to one end of the housing. The fixing assembly includes a first fixing member 26 and a second fixing member 25, and the first fixing member 26 and the second fixing member 25 clamp at least two connectors between the first fixing member 26 and the second fixing member 25.

[0033] Specifically, the electrode patch assembly connected to the connector includes a connection end 34, an output wire 33, and an electrode patch connection part 35. After the connection end 34 is engaged with the connector, the current is conducted to the output wire 33, and the output wire 33 then conducts the current to the electrode patch connection part 35. At the same time, each electrode patch connection part 35 is correspondingly connected to an electrode patch, and the shape and size of the electrode patch can be changed according to the actual situation. Each connector corresponds to a connection end 34, each connection end 34 corresponds to two output wires 33 and the electrode patch connection parts 35 respectively connected to the two output wires 33, and each electrode patch connection part 35 is correspondingly connected to an electrode patch.

[0034] Further, the number of connectors is two, namely a first connector 10 and a second connector 11. Each connector can correspondingly connect to a connection end 34, and each connection end 34 corresponds to a set of positive and negative electrode patches, that is, the above-mentioned portable electrotherapy device can simultaneously use four electrode patches for electrotherapy. Using this portable electrotherapy device can enable the same user to perform electrotherapy on four parts at the same time; or enable two different users to each use a set of positive and negative electrode patches for electrotherapy, improving the electrotherapy efficiency during electrotherapy. At the same time, due to the relatively large number of connectors, the corresponding number of plugging and unplugging times of the electrotherapy device also increases. Excessive plugging and unplugging easily causes the connectors to become loose, affecting the subsequent use of the electrotherapy device. The first fixing member 26 is fixed to the housing and cooperates with the second fixing member 25 to clamp and fix the first connector 10 and the second connector 11 arranged at one end of the circuit board 17 at the same time, avoiding the loosening and shaking of the first fixing member 26 or the second fixing member 25 caused by repeatedly plugging and unplugging the connection end 34; at the same time, it can also make the external force during plugging and unplugging be shared by the two connectors together, preventing the external force from concentrating on one connector and driving the connector to shake. In some other embodiments, the number of connectors can also be three or more.

[0035] Furthermore, the portable electrotherapy device provided in this embodiment is an intermediate frequency electrotherapy device that modulates low-frequency current into intermediate frequency current. The amplitude and frequency of the current change with the amplitude and frequency of the low-frequency current, and then act on specific parts of the human body for rehabilitation treatment.

[0036] Specifically, a first installation groove is provided on one side of the first fixing member 26 close to the connector assembly, and a second installation groove is provided on one side of the second fixing member 25 close to the connector assembly. The first installation groove and the second installation groove cooperate to form at least two installation positions, and at least two connectors are fixedly arranged in the at least two installation positions in a one-to-one correspondence. Further, the cross-sectional shape of the connector is oval, and both the first installation groove and the second installation groove include at least two semi-oval grooves. The first installation groove and the second installation groove cooperate to form at least two oval installation positions, that is, when the first fixing member 26 and the second fixing member 25 are fixedly combined, the peripheral walls of the installation positions are in contact with the peripheral wall of the connector for fixation.

[0037] Specifically, the at least two connectors are spaced apart along the extending direction of one end of the circuit board 17. Specifically, the housing includes a first housing 3 and a second housing 12, and the first housing 3 and the second housing 12 enclose to form a cavity. When the portable electrotherapy device is placed horizontally, the internal circuit board 17 is also placed horizontally, the second housing 12 is located at the bottom, and the first housing 3 is covered on the second housing 12. The first connector 10 and the second connector 11 are arranged at intervals in the horizontal direction. The circuit board 17 and the first fixing member 26 are both fixed to the first housing 3. The first fixing member 26 abuts against one side of the at least two connectors close to the first housing 3, the second fixing member 25 is fixed to the first fixing member 26, and the second fixing member 25 abuts against one side of the at least two connectors away from the first housing 3. The circuit board 17 and the first fixing member 26 are both fixedly connected to the first housing 3. Further, a plurality of circuit board mounting holes are provided on the circuit board 17. The first circuit board 17 can be fixed to the first housing 3 by using screws to pass through the circuit board mounting holes and threadedly connect with the first housing 3. Further, fixing member mounting holes are provided on both the first fixing member 26 and the second fixing member 25. The second fixing member 25 can be fixed to the first fixing member 26 by using screws to pass through the fixing member mounting holes of the second fixing member 25; the screws can pass through the fixing member mounting holes of the first fixing member 26 to fix the first fixing member 26 to the first housing 3. At this time, the first fixing member 26 and the second fixing member 25 jointly clamp the at least two connectors. A limiting groove is provided at one end of the second housing 12, and the fixing assembly is arranged in the limiting groove. The limiting groove can determine the installation position of the fixing assembly and play a role in positioning and limiting the fixing assembly. At this time, the first fixing member 26 and the second fixing member 25 are fixed to the first housing 3 by screws and abut against the limiting groove on the second housing 12 to further strengthen the fixing effect. When the connector is inserted or pulled out, the first housing 3 and the second housing 12 can share the force acting on the connector, further improving the stability at the connector.

[0038] Specifically, at least two connectors are spaced apart along the extension direction of one end of the circuit board 17. The first fixing member 26 is fixed to the first housing 3 and the second housing 12 and abuts against one side of at least two connectors. The second fixing member 25 is fixed to the first fixing member 26 and abuts against the other side of at least two connectors. When the portable electrotherapy device is placed horizontally, the first connector 10 and the second connector 11 are arranged at intervals in the vertical direction. That is, at this time, both ends of the first fixing member 26 are respectively fixed to the first housing 3 and the second housing 12, and the second fixing member 25 is fixed to the first fixing member 26 to cooperate with clamping the connectors. At this time, the first housing 3 and the second housing 12 share the force together, improving the stability at the connectors.

[0039] Specifically, the first housing 3 and the second housing 12 are fixedly connected by snap connection. A plurality of snap protrusions are arranged along the inner circumferential direction of the first housing 3, and a plurality of snap grooves 30 that can be correspondingly and cooperatively snap-connected with the snap protrusions are arranged along the circumferential direction of the second housing 12. When the first housing 3 and the second housing 12 are snap-connected, the snap protrusions are buckled into the corresponding snap grooves 30, so that the first housing 3 and the second housing 12 are relatively fixed. When the first housing 3 and the second housing 12 are detached, only a force that makes them move away from each other needs to be provided to the first housing 3 and the second housing 12 to make the snap protrusions disengage from the snap grooves 30 to complete the detachment, improving the installation efficiency and stability of the housing, allowing for flexible and multiple disassembly, effectively strengthening the integrity of the portable electrotherapy device, and ensuring its aesthetics.

[0040] Specifically, the limiting groove can abut against and limit the fixing component. The limiting groove is arranged directly below the second housing 12 corresponding to the fixing component. When the second housing 12 is fixedly connected to the first housing 3 by snap connection, the top edge and the two side edges of the limiting groove respectively abut against the bottom edge and the two side edges of the fixing component. At this time, the fixing component is directly fixed to the first housing 3, and the first housing 3 can share the force effect for it. The second housing 12 abuts against the fixing component through the limiting groove, sharing the force effect for it.

[0041] Specifically, the above-mentioned portable electrotherapy device further includes a power supply component. A power supply installation position 20 for installing the power supply component is arranged on the second housing 12, and the power supply component is electrically connected to the circuit board 17. Specifically, the power supply component is electrically connected to one side of the circuit board 17 close to the second housing 12 and placed in the power supply installation position 20. Further, the power supply component includes a battery 21, a battery wire 19, and a battery connection socket 18. The battery connection socket 18 is connected to the battery 21 through the battery wire 19 and is plugged into one side of the circuit board 17 close to the second housing 12. Further still, a type-c interface 29 is correspondingly arranged on one side of the circuit board 17 close to the first housing 3 corresponding to the battery connection socket 18. The charger can be inserted into the type-c interface 29 to charge the battery. A type-c interface rubber plug 28 is arranged at the corresponding position of the first housing 3 and the type-c interface 29 to prevent dust from entering the cavity where the electrical appliance is located.

[0042] Specifically, on one side of the circuit board 17 close to the first housing 3, a key assembly and a display assembly are electrically connected. Further, the key assembly includes an up button 5, a down button 6, a selection button 7, a switch button 8, a key board 23, and a key lining 27. The up button 5 and the down button 6 are used to adjust the output power of the electrode plate; the selection button 7 is used to select the output mode of the electrode plate 35; the switch button 8 controls whether the electrode plate works; the key board 23 is electrically connected to the circuit board 17 and is correspondingly arranged with the above keys; the key lining 27 is arranged between the above keys and the key board 23 to play a buffering role. Further, the key assembly is fixed to the circuit board 17 by hexagon head studs 22, and the hexagon head studs 22 can raise the position of the key assembly for easy pressing. The display assembly includes a screen 14 and a screen bracket. The screen bracket is connected to the circuit board 17 through a screen bracket connecting column. The screen bracket is used to support the screen 14, and the screen 14 is electrically connected to the circuit board 17 and can display the working information of the portable electrotherapy device.

[0043] Specifically, the cover plate 2 is covered on one side of the first housing 3 away from the second housing 12. A key limiting member 4 and a lens 9 are arranged on the cover plate 2. The key limiting member 4 is correspondingly arranged with the key assembly, and the lens 9 is correspondingly arranged with the display assembly. The key limiting member 4 is provided with a relief hole for the key assembly to extend out, and the key limiting member 4 abuts against and limits the circumferential surface of the key assembly. The key limiting member 4 can prevent radial displacement when pressing the key assembly, thereby avoiding the shaking of the key assembly under long-term use. The lens 9 covers the display assembly, and the lens 9 is a transparent glass sheet for protecting the display assembly and preventing external liquid or particles from contacting the display assembly. The cover plate 2 is covered on the first housing 3, and the two jointly clamp and fix the lens 9 and the key limiting member 4. Further, the lens 9 and the key limiting member 4 are both provided with connection holes, and screws pass through the connection holes to fix the lens 9 and the key limiting member 4 on the first housing 3 or on the cover plate 2. At this time, the first housing 3, the second housing 12, the cover plate 2, and the components enclosed by the three jointly constitute the portable electrotherapy device main body 1. When the portable electrotherapy device main body 1 is powered on, it can work normally, and users can use its electrotherapy function for electrotherapy.

[0044] Specifically, the portable electrotherapy device further includes a protective cover 31, which is disposed on the first housing 3 and the second housing 12 from the side away from the cover plate 2. A second avoidance hole 36 corresponding to the first avoidance hole is provided on the protective cover 31, and a fixing ring 32 is provided on the side of the protective cover 31 away from the cover plate 2. The protective cover 31 can be a flexible material such as a rubber sleeve or an integrally formed plastic shell. The protective cover 31 can improve the anti-drop ability of the main body 1 of the portable electrotherapy device. And the protective cover 31 does not cover the cover plate 2 together, ensuring that the user can press the button and observe the content displayed by the display component through the lens 9. The second avoidance hole 36 ensures that the required circuit of the electrode sheet can be docked with the connector. At the same time, the fixing ring 32 can be used to pass through a belt or a hanging rope, facilitating the user to fix the position of the portable electrotherapy device when using it, and also enabling the user to perform electrotherapy while moving. Further, a hanging rope hole 13 is also provided at one end of the portable electrotherapy device away from the connector, and a hanging rope avoidance hole is provided at the corresponding position of the protective cover 31. The portable electrotherapy device can be lifted by passing a cord through the hanging rope hole 13, facilitating the carrying of the portable electrotherapy device.

[0045] Obviously, the above-mentioned embodiments of the present invention are merely examples for clearly explaining the present invention, rather than limiting the implementation manners of the present invention. For those of ordinary skill in the art, various obvious changes, re-adjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A portable electrotherapy device, characterized in that: include: a housing, wherein a cavity is formed in the housing; A circuit board (17), the circuit board (17) being arranged in the cavity and fixed to the housing; A connector assembly, the connector assembly being electrically connected to one end of the circuit board (17), the connector assembly comprising at least two connectors, the housing being provided with a first avoidance hole corresponding to the connector assembly; A fixing assembly is fixed to one end of the shell, and the fixing assembly comprises a first fixing member (26) and a second fixing member (25). The first fixing member (26) and the second fixing member (25) cooperate to clamp at least two connectors between the first fixing member (26) and the second fixing member (25).

2. The portable electrotherapy device according to claim 1, characterized in that: A first mounting groove is provided on a side of the first fixing member (26) close to the connector assembly, and a second mounting groove is provided on a side of the second fixing member (25) close to the connector assembly. The first mounting groove and the second mounting groove cooperate to form at least two mounting positions, and at least two connectors are fixed in the at least two mounting positions in a one-to-one correspondence.

3. The portable electrotherapy device according to claim 2, characterized in that: At least two of the connectors are spaced apart and distributed along the extension direction of one end of the circuit board (17).

4. The portable electrotherapy device according to claim 2, characterized in that: At least two of the connectors are spaced apart along an extension direction perpendicular to one end of the circuit board (17).

5. The portable electrotherapy device according to any one of claims 1 to 4, characterized in that: The shell comprises a first shell (3) and a second shell (12), wherein the first shell (3) and the second shell (12) enclose the cavity; the first shell (3) and the second shell (12) are fixed by snapping, a plurality of snapping protrusions are arranged along the circumference of the first shell (3), and a plurality of snapping grooves (30) are arranged along the circumference of the second shell (12) and can be snapped in a one-to-one correspondence with the snapping protrusions.

6. The portable electrotherapy device according to claim 5, characterized in that: The portable electrotherapy device also includes a power supply component. The second shell (12) is provided with a power supply installation position (20) for installing the power supply component. The power supply component is electrically connected to the circuit board (17).

7. The portable electrotherapy device according to claim 5, characterized in that: One end of the second shell (12) is provided with a limiting groove, and the fixing component is arranged in the limiting groove.

8. The portable electrotherapy device according to claim 5, characterized in that: A side of the circuit board (17) close to the first housing (3) is electrically connected to a key assembly and a display assembly.

9. The portable electrotherapy device according to claim 8, characterized in that: The portable electrotherapy device further comprises a cover plate (2), wherein the cover plate (2) is arranged on a side of the first shell (3) away from the second shell (12), and a button stopper (4) and a lens (9) are arranged on the cover plate (2), wherein the button stopper (4) is arranged corresponding to the button assembly, and the lens (9) is arranged corresponding to the display assembly.

10. The portable electrotherapy device according to claim 9, characterized in that: The portable electrotherapy device further comprises a protective cover (31), wherein the protective cover (31) is disposed on the first shell (3) and the second shell (12) from a side away from the cover plate (2); A second avoidance hole is provided on the protection cover (31) corresponding to the first avoidance hole, and a fixing ring (32) is provided on a side of the protection cover (31) away from the cover plate (2).

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