PCR tube switch cap device
By designing a PCR tube cap opening and closing device, which utilizes a flip-out limiting groove and plug structure to enable simultaneous opening and closing of multiple PCR tubes, the problems of low operating efficiency and contamination in existing technologies are solved, thereby improving operating efficiency and experimental safety.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZHONGSHAN HOSPITAL FUDAN UNIV
- Filing Date
- 2025-07-22
- Publication Date
- 2026-07-10
AI Technical Summary
In the existing technology, the opening and closing operation of PCR tube caps is inefficient, as only one cap can be opened or closed at a time. During operation, the caps are easily contaminated by gloves, and multiple caps can easily mix, leading to sample contamination.
A PCR tube cap opening and closing device was designed, including a support structure and a cap opening and closing structure. The cap opening and closing structure is flip-connected to the support structure and is provided with multiple limiting grooves and plugs. The cap opening and closing of multiple PCR tubes can be achieved simultaneously by flipping the cap, avoiding manual contact with the cap and preventing cap contamination and mixing.
This improves the efficiency of opening and closing PCR tube caps, avoids cap contamination and sample contamination, and ensures the accuracy and safety of experiments.
Smart Images
Figure CN224477925U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of medical device technology, and in particular to a PCR tube opening and closing device. Background Technology
[0002] PCR tubes are an indispensable key consumable in polymerase chain reaction experiments, mainly used to provide a closed and stable container environment for DNA amplification reactions.
[0003] In existing technologies, PCR tubes are usually placed on a support rack. When needed, staff manually open or close the cap of a PCR tube using their index finger and thumb. Only one cap can be opened or closed at a time. After the cap is opened, it is placed aside. During the opening operation, gloves are easily contaminated with the cap. After opening multiple caps in succession, multiple caps are easily mixed during the subsequent closing operation, which leads to sample contamination inside the PCR tube.
[0004] That is, the current method involves staff manually opening and closing the caps of multiple PCR tubes, with only one cap being opened or closed at a time. This method is inefficient, the caps are easily contaminated by gloves during operation, and multiple caps can easily mix, leading to sample contamination inside the PCR tubes. Utility Model Content
[0005] The purpose of this invention is to provide a PCR tube opening and closing device to solve the problems of low efficiency, easy contamination of the cap by gloves, and easy mixing of multiple caps, which can lead to sample contamination inside the PCR tube.
[0006] To achieve this objective, the present invention adopts the following technical solution:
[0007] This utility model provides a PCR tube switch cap device, including a support structure and a switch cap structure. The switch cap structure is rotatably connected to the support structure. The support structure is provided with a receiving hole for accommodating the tube body of the PCR tube. The end of the switch cap structure is recessed with a limiting groove and protruding with a plug. Multiple limiting grooves and plugs are provided, and each limiting groove is located between two adjacent plugs. The limiting groove matches the tube body.
[0008] The switch cover structure has an open state and a closed state. In the open state, the switch cover structure flips and moves away from the support structure, so that the two adjacent plugs are respectively lifted from both sides and placed in the corresponding limiting grooves of the PCR tube caps, and the caps are locked in the switch cover structure to separate from the tube body. In the closed state, the switch cover structure flips and moves closer to the support structure, so that the tube body is inserted into the limiting groove, the plugs are inserted between adjacent tube bodies, and the caps are placed on the tube body.
[0009] As an optional technical solution for a PCR tube switch cap device, the end of the switch cap structure is further provided with a stop portion, the stop portion is spaced apart from the plug, and the cap of the PCR tube is engaged between the stop portion and the plug.
[0010] As an optional technical solution for a PCR tube switch cap device, the stop portion has a groove on the side facing closer to the plug, and the groove is used for inserting the cap portion.
[0011] As an optional technical solution for a PCR tube opening and closing device, the supporting structure includes a base and a limiting plate connected to the base. The receiving hole is disposed on the limiting plate. The base has a receiving space communicating with the receiving hole, so that the tube body of the PCR tube passes through the receiving hole and is partially placed in the receiving space. The receiving space is used to place a heating element to heat the tube body.
[0012] As an optional technical solution for a PCR tube opening and closing device, the inner wall of the receiving hole is provided with an elastic layer, and the PCR tube body is fixed in the receiving hole under the squeezing action of the elastic layer.
[0013] As an optional technical solution for a PCR tube opening and closing device, the supporting structure and the opening and closing structure are an integral structure made of plastic material.
[0014] As an optional technical solution for a PCR tube switching cap device, the supporting structure and the switching cap structure are rotatably connected by a rotating shaft or by an elastic element.
[0015] As an optional technical solution for a PCR tube opening and closing device, one of the supporting structure and the opening and closing structure is provided with a slot, and the other is provided with a buckle that cooperates with the slot. When the opening and closing structure is in the closed state, the slot and the buckle are engaged.
[0016] As an optional technical solution for a PCR tube switch cap device, the switch cap structure includes a first connecting part and a second connecting part. The first connecting part is rotatably connected to the support structure, one end of the second connecting part is slidably inserted into the first connecting part, and the limiting groove and the plug are disposed at the other end of the second connecting part.
[0017] As an optional technical solution for a PCR tube switching cap device, it also includes a positioning component, the two ends of which are respectively connected to the supporting structure and the switching cap structure. The positioning component is used to limit the switching cap structure to maintain a preset flip angle θ.
[0018] Beneficial effects:
[0019] This invention provides a PCR tube opening and closing device, which includes a support structure and an opening and closing structure. The opening and closing structure is rotatably connected to the support structure. The support structure has a receiving hole for accommodating the PCR tube body. The end of the opening and closing structure has a recessed limiting groove and a protruding plug. Multiple limiting grooves and plugs are provided, and each limiting groove is located between two adjacent plugs. The limiting groove matches the tube body. The opening and closing structure has an open state and a closed state. In the open state, the opening and closing structure flips and moves away from the support structure, so that two adjacent plugs are respectively lifted from both sides and placed in the corresponding limiting grooves of the PCR tube cap, and the cap is locked in the opening and closing structure to separate from the tube body. In the closed state, the opening and closing structure flips and moves closer to the support structure, so that the tube body is inserted into the limiting groove, the plug is inserted between adjacent tube bodies, and the cap is placed on the tube body. By setting up a switch cap structure connected to the support structure, multiple limiting grooves and multiple plugs are set at the end of the switch cap structure. By operating the switch cap structure to flip it over, the limiting grooves are used to position the tube body, and two adjacent plugs are used to pry up the cap from both sides, realizing the opening operation of PCR tubes. This replaces the existing method of directly manually operating the tube cap and avoids the cap being contaminated due to direct contact with gloves. With the cooperation of multiple limiting grooves and multiple plugs, multiple PCR tubes can be operated at the same time with one flip of the switch cap structure, improving the operation efficiency. After opening, the cap is locked on the switch cap structure, and when closing the cap, flipping the switch cap structure in the opposite direction will put the cap on the corresponding tube body, preventing multiple caps from mixing and causing sample contamination after closing. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the PCR tube opening and closing device provided in this embodiment of the present invention;
[0021] Figure 2 This is a first structural schematic diagram of the PCR tube opening and closing device provided in this embodiment of the present invention;
[0022] Figure 3This is a schematic diagram of the second structure of the PCR tube opening and closing device provided in this embodiment of the present invention;
[0023] Figure 4 This is a partial structural schematic diagram of the PCR tube switch cap device provided in this embodiment of the utility model;
[0024] Figure 5 This is a cross-sectional view of the load-bearing structure provided in an embodiment of this utility model.
[0025] In the picture:
[0026] 10. Load-bearing structure; 11. Base; 111. Accommodating space; 12. Limiting plate; 121. Accommodating hole;
[0027] 20. Switch cover structure; 21. First connecting part; 22. Second connecting part; 221. Limiting groove; 222. Plug; 23. Stopping part;
[0028] 30. Positioning components. Detailed Implementation
[0029] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.
[0030] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0031] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0032] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.
[0033] like Figures 1 to 5 As shown, this embodiment provides a PCR tube switching cap device, which includes a support structure 10 and a switching cap structure 20. The switching cap structure 20 is rotatably connected to the support structure 10. The support structure 10 has a receiving hole 121 for receiving the tube body of the PCR tube. The end of the switching cap structure 20 has a limiting groove 221 recessed and a plug 222 protruding. Multiple limiting grooves 221 and plugs 222 are provided, and each limiting groove 221 is located between two adjacent plugs 222. The limiting groove 221 and the tube are connected... The body is matched; the switch cover structure 20 has an open state and a closed state. In the open state, the switch cover structure 20 flips and moves away from the support structure 10 so that the two adjacent plugs 222 are respectively lifted from both sides and placed in the corresponding limiting grooves 221 of the PCR tube cover, and the cover is locked in the switch cover structure 20 to separate from the tube body; in the closed state, the switch cover structure 20 flips and moves closer to the support structure 10 so that the tube body is inserted into the limiting groove 221, the plugs 222 are inserted between adjacent tube bodies, and the cover is placed on the tube body.
[0034] By setting a switch cover structure 20 connected to the support structure 10, multiple limiting grooves 221 and multiple plugs 222 are set at the end of the switch cover structure 20. When the switch cover structure 20 is flipped, the tube body is positioned by the limiting grooves 221, and the cap body is lifted from both sides by two adjacent plugs 222, realizing the opening operation of PCR tubes. This replaces the existing method of directly manually operating the tube cap and avoids the cap body being contaminated due to direct contact of gloves with the cap body. With the cooperation of multiple limiting grooves 221 and multiple plugs 222, multiple PCR tubes can be operated at the same time by flipping the switch cover structure 20 once, which improves the operation efficiency. After the cap is opened, the cap body is locked on the switch cover structure 20, and when closing the cap, the switch cover structure 20 is flipped in the opposite direction to place the cap body on the corresponding tube body. This will prevent multiple cap bodies from mixing and causing sample contamination after closing.
[0035] In this embodiment, the supporting structure 10 is provided with multiple sets of receiving holes 121, and each set includes eight receiving holes 121 for accommodating a set of eight-tube bundles; the supporting structure 10 is provided with one or more switch cover structures 20, each switch cover structure 20 is provided with eight limiting grooves 221 and nine plugs 222, and the opening or closing operation of the eight-tube bundle can be completed simultaneously by flipping one switch cover structure 20; the limiting groove 221 is an arc-shaped groove and the inner wall of the arc-shaped groove is used to fit against the side wall of the tube body, and the plug 222 is an arc-shaped protrusion. The eight-tube bundle is an integrated design of PCR tubes, specifically composed of eight independent PCR tube bodies connected into one piece, and the cap of each PCR tube can be detached from the corresponding tube body. Each PCR tube can hold reaction solution separately for parallel experiments.
[0036] In one embodiment, the supporting structure 10 and the switch cover structure 20 are an integral structure made of plastic. By using plastic to integrate the switch cover structure 20 and the supporting structure 10, and utilizing the foldable connection between the switch cover structure 20 and the supporting structure 10, the switch cover structure 20 can be flipped. The plastic material includes, but is not limited to, polypropylene and polycarbonate.
[0037] See Figure 2 Optionally, the load-bearing structure 10 and the switch cover structure 20 are rotatably connected by a pivot. This allows the load-bearing structure 10 and the switch cover structure 20 to be manufactured separately and then assembled together via the pivot, resulting in low manufacturing difficulty, strong structural stability, and high flexibility. Furthermore, the pivot can be a damped pivot to position the switch cover structure 20, maintaining it at a specific tilting angle.
[0038] Optionally, the PCR tube opening and closing device further includes a positioning element 30. The two ends of the positioning element 30 are connected to the supporting structure 10 and the opening and closing structure 20, respectively. The positioning element 30 is used to limit the opening and closing structure 20 to maintain a preset flip angle θ. By setting the positioning element 30, the opening and closing structure 20 can be kept at the preset flip angle θ, i.e., in an upright or tilted state, preventing the opening and closing structure 20 from lying flat on the supporting structure 10 and occupying a large space. The preset flip angle θ ranges from 90 degrees to 135 degrees.
[0039] The positioning element 30 can be a support rod. The positioning element 30 and the PCR tube are located on both sides of the switch cover structure 20. The side of the positioning element 30 closest to the switch cover structure 20 has a positioning plane for fitting with one side of the switch cover structure 20.
[0040] Specifically, the end of the switch cover structure 20 away from the limiting groove 221 is connected to the bearing structure 10 via a pivot, or the middle part of the switch cover structure 20 is connected to the bearing structure 10 via a pivot, and an avoidance groove is provided on the bearing structure 10, thereby providing a space for movement of the end of the switch cover structure 20 away from the limiting groove 221.
[0041] If the end of the switch cover structure 20 away from the limiting groove 221 is connected to the bearing structure 10 through a rotating shaft, then the switch cover structure 20 can rotate within a range of 180 degrees around the rotating shaft; if the middle part of the switch cover structure 20 is connected to the bearing structure 10 through a rotating shaft, then when the switch cover structure 20 is flipped open, the end of the switch cover structure 20 with the limiting groove 221 gradually moves away from the bearing structure 10, and the end of the switch cover structure 20 away from the limiting groove 221 gradually inserts into the clearance groove of the bearing structure 10, and the switch cover structure 20 can rotate within a range of 90 degrees around the rotating shaft.
[0042] In another embodiment, the supporting structure 10 and the switch cover structure 20 are connected by an elastic element. This elastic element can be a spring. Accordingly, the end of the switch cover structure 20 furthest from the limiting groove 221 is connected to the supporting structure 10 via the elastic element, or the middle portion of the switch cover structure 20 is connected to the supporting structure 10 via an elastic element. Connecting the supporting structure 10 and the switch cover structure 20 with an elastic element allows the switch cover structure 20 to rotate using the elastic force of the element. This allows for some compensation of the position of the switch cover structure 20 based on the deformation of the elastic element, making the position of the switch cover structure 20 adjustable and more flexible.
[0043] See Figure 3 Optionally, the switch cover structure 20 includes a first connecting part 21 and a second connecting part 22. The first connecting part 21 is rotatably connected to the supporting structure 10. One end of the second connecting part 22 is slidably inserted into the first connecting part 21, and a limiting groove 221 and a plug 222 are provided at the other end of the second connecting part 22. By providing the first connecting part 21 and the second connecting part 22, one end of the second connecting part 22 is slidably engaged with the first connecting part 21, and the other end of the second connecting part 22 is provided with a limiting groove 221 and a plug 222, thereby enabling the switch cover structure 20 to extend and retract to adjust its length, thus ensuring that the plug 222 can be inserted between two adjacent tubes when the cover is closed.
[0044] It is understandable that the positioning between the first connecting part 21 and the second connecting part 22 can be achieved by sliding into place and locking through a snap-fit structure, or by inserting a plug into the first connecting part 21 and the second connecting part 22 to achieve locking; if the retractable switch cover structure 20 is not used, the plug 222 can also be inserted between adjacent tubes by utilizing the deformation of the switch cover structure 20 itself; the shape of the first connecting part 21 and the second connecting part 22 can be adjusted according to actual needs.
[0045] See Figure 4 Optionally, the end of the switch cover structure 20 is further provided with a stop portion 23, which is spaced apart from the plug 222. The cover of the PCR tube is engaged between the stop portion 23 and the plug 222. By providing the stop portion 23 on the switch cover structure 20, and spaced apart from the plug 222, the cover can be engaged between the stop portion 23 and the plug 222. When the plug 222 lifts the cover, the stop portion 23 can play a certain blocking role to prevent the cover from detaching from the switch cover structure 20. When closing the cover, the stop portion 23 can also exert a certain downward pressure on the cover, causing the cover to be placed on the tube body.
[0046] In this embodiment, since the outer diameter of the cover is larger than the maximum outer diameter of the tube, the cover can be locked between the stop 23 and the plug 222; the stop 23 is located on the side of the plug 222 away from the bearing structure 10; the stop 23 is flat and has a wavy edge.
[0047] Optionally, the stop portion 23 has a groove on the side facing the plug 222, the groove being for the cover to be partially inserted. By adding a groove on the side of the stop portion 23 facing the plug 222, the cover is at least partially inserted into the groove, further ensuring that the cover can be stably placed on the switch cover structure 20 after opening and can flip with the switch cover structure 20.
[0048] See Figure 5 The supporting structure 10 includes a base 11 and a limiting plate 12. The limiting plate 12 is connected to the base 11, and a receiving hole 121 is disposed on the limiting plate 12. The base 11 has a receiving space 111 that communicates with the receiving hole 121, so that the PCR tube body passes through the receiving hole 121 and is partially placed in the receiving space 111. The receiving space 111 is used to place a heating element to heat the tube body. By setting the base 11 and the limiting plate 12, and setting the receiving hole 121 on the limiting plate 12, and setting the receiving space 111 in the base 11, when the PCR tube body is inserted into the receiving hole 121, it can be partially placed in the receiving space 111, and the heating element placed in the receiving space 111 can be used to heat the tube body, meeting the heating requirements of the PCR tube, and ensuring the uniformity of heating by heat conduction.
[0049] The tube body can be heated by water bath heating, where water is placed in the containment space 111 as the heating medium to indirectly heat the tube body; or by metal bath heating, where a metal module is placed in the containment space 111 and the metal module is in direct contact with the tube body to heat and control the tube body temperature; the base 11 and the limiting plate 12 can be an integral structure, or the base 11 and the limiting plate 12 can be detachably connected, for example, by snap-fit.
[0050] In this embodiment, the base 11 has an opening at the top, and the limiting plate 12 is connected to the base 11 and closes the opening at the top of the base 11; the switch cover structure 20 is rotatably connected to the side of the limiting plate 12 away from the base 11.
[0051] Optionally, the inner wall of the well 121 is provided with an elastic layer. Under the compression of the elastic layer, the PCR tube is fixed inside the well 121. The elastic layer is a deformable rubber ring. By providing an elastic layer on the inner wall of the well 121, the elastic layer fills the gap between the PCR tube and the inner wall of the well 121, and compresses and fixes the PCR tube, so that the PCR tube is stably fixed inside the well 121. This prevents the pipette from lifting up and taking the tube along with it when adding reagents to the PCR tube using a pipette connector, which would affect the accuracy of the experiment.
[0052] Optionally, one of the supporting structure 10 and the switch cover structure 20 is provided with a slot, and the other is provided with a buckle that mates with the slot. When the switch cover structure 20 is in the closed state, the slot and the buckle engage. By setting the supporting structure 10 and the switch cover structure 20 to engage when the cover is closed, the cover of the PCR tube remains stable after closing, preventing the cover from bursting due to temperature rise during heating in a water bath or metal bath, thus avoiding sample spillage and contamination within the PCR tube and sample loss. It is understood that when the cover is open, the slot and the buckle separate; the specific positions of the slot and the buckle can be adjusted according to the actual shape of the PCR tube switch cover device.
[0053] The PCR tube opening and closing device provided in this embodiment places the tube body of an eight-tube bundle within the receiving hole 121 of the support structure 10. By adding an elastic layer to the inner wall of the receiving hole 121, the tube body of the PCR tube can be fixed within the receiving hole 121. The opening or closing operation is performed by flipping the opening and closing structure 20, replacing the direct manual opening and closing method. This helps protect the sample inside the eight-tube bundle from contamination and also prevents injury to the operator's fingers from high-intensity opening and closing operations. When adding reagents to the eight-tube bundle, the tube body will not shift under the limiting effect of the receiving hole 121. After the closing operation, the support structure 10 and the opening and closing structure 20 engage to ensure that the cap is placed on the tube body, and there will be no cap bursting even when heated in a water bath or metal bath.
[0054] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make various obvious changes, readjustments, and substitutions without departing from the protection scope of this utility model. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.
Claims
1. A PCR tube opening and closing device, characterized in that, The device includes a support structure (10) and a switch cover structure (20). The switch cover structure (20) is rotatably connected to the support structure (10). The support structure (10) is provided with a receiving hole (121) for receiving the tube body of the PCR tube. The end of the switch cover structure (20) is recessed with a limiting groove (221) and protruded with a plug (222). Multiple limiting grooves (221) and plugs (222) are provided, and each limiting groove (221) is located between two adjacent plugs (222). The limiting groove (221) matches the tube body. The switch cover structure (20) has an open state and a closed state. In the open state, the switch cover structure (20) flips and moves away from the support structure (10) so that the two adjacent plugs (222) are respectively lifted from both sides and placed in the corresponding limiting grooves (221) of the PCR tube cap, and the cap is locked in the switch cover structure (20) to separate from the tube body. In the closed state, the switch cover structure (20) flips and moves closer to the support structure (10) so that the tube body is inserted into the limiting groove (221), the plug (222) is inserted between the adjacent tube bodies, and the cap is placed on the tube body.
2. The PCR tube opening and closing device according to claim 1, characterized in that, The end of the switch cover structure (20) is also provided with a stop (23), the stop (23) and the plug (222) are spaced apart, and the cover of the PCR tube is locked between the stop (23) and the plug (222).
3. The PCR tube opening and closing device according to claim 2, characterized in that, The stop (23) has a groove on the side facing the plug (222), and the groove is used for inserting the cover part.
4. The PCR tube opening and closing device according to claim 1, characterized in that, The supporting structure (10) includes a base (11) and a limiting plate (12) connected to the base (11). The receiving hole (121) is disposed on the limiting plate (12). The base (11) is provided with a receiving space (111) communicating with the receiving hole (121) so that the tube body of the PCR tube passes through the receiving hole (121) and is partially placed in the receiving space (111). The receiving space (111) is used to place a heating element to heat the tube body.
5. The PCR tube opening and closing device according to claim 1, characterized in that, The inner wall of the receiving hole (121) is provided with an elastic layer, and the tube body of the PCR tube is fixed in the receiving hole (121) under the squeezing action of the elastic layer.
6. The PCR tube opening and closing device according to claim 1, characterized in that, The supporting structure (10) and the switch cover structure (20) are an integral structure made of plastic material.
7. The PCR tube opening and closing device according to claim 1, characterized in that, The load-bearing structure (10) and the switch cover structure (20) are rotatably connected by a rotating shaft or by an elastic element.
8. The PCR tube opening and closing device according to claim 1, characterized in that, One of the supporting structure (10) and the switch cover structure (20) is provided with a slot, and the other is provided with a buckle that cooperates with the slot. When the switch cover structure (20) is in the closed state, the slot and the buckle are engaged.
9. The PCR tube opening and closing device according to claim 1, characterized in that, The switch cover structure (20) includes a first connecting part (21) and a second connecting part (22). The first connecting part (21) is rotatably connected to the bearing structure (10). One end of the second connecting part (22) is slidably inserted into the first connecting part (21). The limiting groove (221) and the plug (222) are disposed at the other end of the second connecting part (22).
10. The PCR tube opening and closing device according to any one of claims 1-9, characterized in that, It also includes a positioning element (30), the two ends of which are connected to the bearing structure (10) and the switch cover structure (20) respectively. The positioning element (30) is used to limit the switch cover structure (20) to maintain a preset flip angle θ.