Multi-stage propelling device
By designing a multi-stage propulsion device, and using trigger keys and magnet drives, segmented adjustment of the electromagnetic propulsion device is achieved, solving the problem of the inability to adjust the propulsion distance in the prior art, and improving control flexibility and operation convenience.
Patent Information
- Application Number
- CN202422055078.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-23
- Publication Date
- 2025-07-25
- Estimated Expiration
- 2034-08-23
AI Technical Summary
The existing electromagnetic propulsion device cannot achieve segmented adjustment of the propulsion distance, reducing the flexibility of propulsion control.
A multi-stage propulsion device is designed, including a moving component and a trigger key. By pressing different trigger keys, the moving push rod is pushed to different positions in stages, and the electromagnetic suction driving of the fixed magnet and the moving magnet is driven, combined with the cooperation of the elastic member and the clamping member, two-stage propulsion is achieved.
The function of adjusting the propulsion distance in stages is realized, which improves the flexibility of propulsion control, is simple to operate and compact in structure.
Smart Images
Figure CN223156944U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to a multi-stage propulsion device capable of advancing in stages. Background Art
[0002] In existing electromagnetic propulsion devices, under the interaction of a first magnet and a second magnet, movement or propulsion over a single stroke distance is achieved. However, the object carried in this way cannot adjust the distance during forward movement, that is, it cannot adjust the propulsion distance in segments, reducing the flexibility of propulsion control. Summary of the Invention
[0003] An object of the present application is to provide a multi-stage propulsion device capable of advancing in stages. To achieve the above object, in one solution of the present application, a multi-stage propulsion device includes a moving component capable of moving in a first direction; the moving component includes a moving magnet and a moving push rod connected to each other; during the first-stage propulsion, the moving magnet pushes the moving push rod to move from an initial position in the first direction to a first position, and the moving component is locked; during the second-stage propulsion, the moving component is unlocked, and the moving magnet further pushes the moving push rod to move in the first direction to a second position, and the moving component is locked.
[0004] In a preferred manner, when the moving push rod is at the second position and the moving component is unlocked, the moving push rod can retract in the opposite direction of the first direction to the first position, and the moving component is locked; thereafter, when the moving component is unlocked again, the moving push rod can retract in the opposite direction of the first direction to the initial position.
[0005] In a preferred manner, it includes a first trigger key and a second trigger key; when the first trigger key is pressed to a first trigger position, the moving magnet drives the moving push rod to move to the first position; when the second trigger key is pressed to a second trigger position, the moving component is unlocked, and the moving magnet drives the moving push rod to move to the second position.
[0006] In a preferred manner, the second trigger key is arranged more rearward than the first trigger key in the pressing direction; thus, after pressing the first trigger key to the first trigger position, continuing to press the first trigger key can touch and press the second trigger key.
[0007] In a preferred manner, after pressing the second trigger key to the second trigger position, continuing to press the second trigger key, and then unlocking the moving component via a transmission mechanism.
[0008] In a preferred embodiment, the multi-stage propulsion device includes a first engaging member extending along a direction intersecting the first direction; the moving push rod includes a push rod slot; when the moving push rod moves to the first position, the first engaging member is engaged with the push rod slot.
[0009] In a preferred embodiment, the multi-stage propulsion device includes a second engaging member extending along a direction intersecting the first direction; when the moving push rod moves to the second position, the second engaging member is engaged with the moving magnet.
[0010] In a preferred embodiment, the moving assembly includes a fixed magnet sleeved on the outer periphery of the moving magnet; the fixed magnet is fixed to the first bracket; an elastic member is connected between the moving magnet and the fixed magnet; when the moving magnet moves along the first direction, the elastic member deforms and stores energy; when the moving assembly is unlocked at the second position, the elastic member pushes the moving magnet and the moving push rod to rebound and reset in the opposite direction of the first direction.
[0011] In a preferred embodiment, an unlocking member capable of moving along a direction intersecting the first direction is included, and the unlocking member has a first unlocking portion and a second unlocking portion capable of abutting against the first engaging member and the second engaging member respectively; when the moving magnet is located at the second position, the unlocking member is pushed, so that the first unlocking portion and the second unlocking portion respectively push the first engaging member and the second engaging member to move, thereby unlocking the moving assembly.
[0012] In a preferred embodiment, the transmission mechanism is arranged as a swing rod capable of rotating around a swing rod axis; one end of the swing rod is close to the first engaging member and the other end is close to the second trigger key; after pressing the second trigger key to the second trigger position and continuing to press the second trigger key, the second trigger key abuts against the end of the swing rod far from the first engaging member and drives the swing rod to rotate, so that the end of the swing rod close to the first engaging member pushes the first engaging member to move and disengage from the push rod slot, thereby unlocking the moving assembly.
[0013] In a preferred embodiment, the first engaging member is connected with a first engaging elastic member; in the initial state, the first engaging elastic member is in a state of storing energy; when the moving push rod moves to the first position, the first engaging elastic member pushes the first engaging member into the push rod slot to limit the displacement of the moving push rod.
[0014] In a preferred embodiment, the second engaging member is connected with a second engaging elastic member; in the initial state, the second engaging elastic member is in a state of storing energy; when the moving push rod moves to the second position, the second engaging elastic member pushes the second engaging member into a predetermined position to limit the displacement of the moving push rod.
[0015] In a preferred embodiment, it includes a first limiting portion and a second limiting portion which are arranged at intervals along the first direction; when the moving magnet moves to the second position, the first limiting portion abuts against the moving magnet to limit its displacement along the first direction; when the moving magnet retreats to the initial position, the second limiting portion abuts against the moving magnet to limit its displacement along the opposite direction of the first direction.
[0016] According to the foregoing technical solution, by means of a one-stop key, the continuous advancement of the first stroke distance and the second stroke distance is solved, and the function of at least two-stage and phased adjustment is realized. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] In order to illustrate the present application more clearly, the accompanying drawings of the present application will be described and explained below. Obviously, the accompanying drawings in the following description only illustrate some aspects of certain exemplary embodiments of the present application, and those of ordinary skill in the art can obtain other accompanying drawings based on these drawings without creative efforts.
[0018] Figure 1 It is a schematic diagram of the initial state of an exemplary multi-stage propulsion device.
[0019] Figure 2 It is a schematic diagram of the first-stage propulsion of an exemplary multi-stage propulsion device.
[0020] Figure 3 It is a schematic diagram of the second-stage propulsion of an exemplary multi-stage propulsion device.
[0021] Figure 4 It is a schematic diagram of an exemplary multi-stage propulsion device and its partial enlarged view.
[0022] Description of the accompanying drawing text:
[0023] 1 Moving magnet
[0024] 10 Second bracket
[0025] 11 Magnet baffle
[0026] 12 Elastic member
[0027] 13 First limiting portion
[0028] 14 Second limiting portion
[0029] 15 Magnet limiting part
[0030] 2 Moving push rod
[0031] 21 Push rod slot
[0032] 3 First bracket
[0033] 31 Fixed magnet
[0034] 4 Unlocking part
[0035] 40 Up and down arrow
[0036] 41 First unlocking part
[0037] 42 Second unlocking part
[0038] 5 First clamping part
[0039] 51 First clamping enabling end
[0040] 52 First clamping horizontal end
[0041] 53 First clamping elastic part
[0042] 6 Second clamping part
[0043] 61 Second clamping enabling end
[0044] 62 Second clamping horizontal end
[0045] 63 Second clamping elastic part
[0046] 7 First trigger key
[0047] 71 First trigger point
[0048] 72 Second trigger point
[0049] 8 Second trigger key
[0050] 81 Third trigger point
[0051] 82 Fourth trigger point
[0052] 83 Rear end face of the second trigger key
[0053] 9 Swing rod
[0054] 90 Swing rod shaft Detailed implementation method
[0055] Various exemplary embodiments of the present application will be described in detail below with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and in no way limits the present application and its application or use. The present application can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present application thorough and complete, and to fully convey the scope of the present application to those skilled in the art. It should be noted that: unless otherwise specified, the relative arrangements of components and steps, numerical expressions and numerical values, etc. set forth in these embodiments should be construed as merely exemplary and not as limitations.
[0056] The terms such as "including" or "comprising" used in the present application are intended to mean that the elements before this word cover the elements listed after this word, and do not exclude the possibility of also covering other elements.
[0057] All terms used in the present application (including technical terms or scientific terms) have the same meaning as understood by those of ordinary skill in the art to which the present application pertains, unless otherwise specifically defined. It should also be understood that terms defined in a general dictionary should be construed as having a meaning consistent with their meaning in the context of the relevant art, and should not be interpreted in an idealized or overly formal sense, unless expressly so defined herein.
[0058] For the components not described in detail in this part, the specific model parameters of the components, the mutual relationships between the components, and the control circuit, they can be considered as technologies, methods, and devices known to those of ordinary skill in the relevant art. However, in appropriate cases, the said technologies, methods, and devices should be regarded as part of the specification.
[0059] The following refers to Figures 1-3 to illustrate the composition of the multi-stage propulsion device of the present application. Figure 1 is a schematic diagram of the initial state of the multi-stage propulsion device, Figure 2 is a schematic diagram of the first-stage propulsion of the multi-stage propulsion device, Figure 3 is a schematic diagram of the second-stage propulsion of the multi-stage propulsion device.
[0060] Refer to Figure 1 , the multi-stage propulsion device of the present application includes a moving component capable of moving in a first direction. The moving component includes a moving magnet 1 and a moving push rod 2 connected to each other. For the convenience of description, the first direction is the front and back direction in which the moving push rod 2 moves, the direction perpendicular to the first direction on the paper is the up and down direction, and the direction from the moving magnet 1 towards the moving push rod 2 shown in the figure is the front, and vice versa is the back.
[0061] In this embodiment, the moving magnet 1 is arranged in such a way that it passes through the first bracket 3, and the first bracket 3 is arranged on the second bracket 10. A fixed magnet 31 is sleeved on the outer periphery of the first bracket 3. The fixed magnet 31 is usually a coil, which generates electromagnetic suction force when energized and drives the moving magnet 1 to move.
[0062] A magnet baffle 11 is provided at the rear end of the moving magnet 1, and an elastic member 12 is provided between the magnet baffle 11 and the first bracket 3. At this time, the elastic member 12 is sleeved on the outer periphery of the moving magnet 1. In the initial state, the elastic member 12 is not deformed.
[0063] During the first-stage propulsion, the fixed magnet 31 is energized and drives the moving magnet 1 to move in the first direction. The moving magnet 1 synchronously pushes the moving push rod 2 to advance in the first direction by a first propulsion distance to a first position, and the moving assembly is locked at the first position; during the second-stage propulsion, the moving assembly is unlocked at the first position, the fixed magnet 31 is energized to generate electromagnetic suction force and drives the moving magnet 1 to continue moving in the first direction. The moving magnet 1 synchronously pushes the moving push rod 2 to continue advancing in the first direction by a second propulsion distance to a second position, and the moving assembly is locked again at the second position.
[0064] See Figure 2 , the moving push rod 2 includes a push rod slot 21; the multi-stage propulsion device further includes a first clamping member 5. The first clamping member 5 has a first clamping enabling end 51 extending in the up-down direction and a first clamping horizontal end 52 extending in the horizontal direction. The first clamping member 5 is connected with a first clamping elastic member 53. In the initial state, the first clamping member 5 is under the acting force of being pressed downward by the moving push rod 2, so that the first clamping elastic member 53 is squeezed and in a state of storing energy. When the moving magnet 1 advances to the first position, the elastic member 12 deforms and stores energy, and the push rod slot 21 moves to a position corresponding to the first clamping member 5. The first clamping elastic member 53 pushes the first clamping member 5 to move upward, so that the first clamping enabling end 51 is inserted into the push rod slot 21, thereby restricting the movement of the moving push rod 2 in the front-rear direction and locking the moving assembly.
[0065] This embodiment further includes a swing rod 9 that can rotate around a swing rod axis 90; exemplarily, the swing rod 9 is generally L-shaped with an obtuse angle, presenting the illustrated bent shape. Its front end is located above the first clamping horizontal end 52, and its rear end is located at a position that can be triggered by a second trigger key 8 described later. Continuously pressing the second trigger key 8 can make its rear end face, i.e., the rear end face 83 of the second trigger key, abut against the rear end of the swing rod 9 and drive the swing rod 9 to rotate. The swing rod 9 rotates around the swing rod axis 90, causing the front end of the swing rod 9 to press down and push the first clamping horizontal end 52 to move downward, thereby making the first clamping enabling end 51 disengage from the push rod slot 21, unlocking the moving assembly, and enabling the moving push rod 2 to move back and forth.
[0066] At this time, the moving magnet 1 continues to push the moving push rod 2 forward to a predetermined second position, such asFigure 3 As shown, the elastic member 12 further deforms and stores energy. The multi-stage propulsion device includes a second clamping member 6; the second clamping member 6 includes a second clamping enabling end 61 extending in the up-down direction and a second clamping horizontal end 62. The second clamping member 6 is also connected with a second clamping elastic member 63.
[0067] In the initial state, the second clamping elastic member 63 deforms and stores energy. When the moving push rod 2 moves to the second position, the magnet baffle 11 moves to the front side of the second clamping member 6, and the second clamping elastic member 63 pushes the second clamping member 6 upward, so that the second clamping enabling end 61 abuts against the magnet baffle 11 to limit the backward movement of the moving magnet 1. When the fixed magnet 31 is powered off, the moving magnet 1 is locked under the action of the backward elastic force of the elastic member 12 and the restriction of the second clamping member 6.
[0068] As an example, the multi-stage propulsion device further includes an unlocking member 4 capable of moving in the up-down direction. The unlocking member 4 has a first unlocking portion 41 and a second unlocking portion 42 that can respectively abut against the first clamping horizontal end 52 and the second clamping horizontal end 62. When the moving magnet 1 is in the second position, the unlocking member 4 is pushed downward along the up-down arrow 40 shown in the figure, so that the first unlocking portion 41 and the second unlocking portion 42 respectively abut against the first clamping horizontal end 52 and the second clamping horizontal end 62 and push the two downward, and then the first clamping enabling end 51 moves downward to a position where it will not be inserted into the push rod slot 21, and the second clamping enabling end 61 moves downward to a position where it no longer restricts the magnet baffle 11, and the moving assembly is unlocked. After that, the elastic member 12 drives the moving magnet 1 and the moving push rod 2 to rebound and reset to the initial position.
[0069] As a preferred manner, the present application provides a trigger key assembly, which includes a first trigger key 7 and a second trigger key 8. As Figure 2 、 Figure 3 shown, exemplarily, the first trigger key 7 is arranged in a manner of passing through the second trigger key 8 in the front-rear direction. Since the second trigger key 8 is arranged more rearward relative to the first trigger key 7; thus, when pressing the trigger key assembly in the front-to-back direction, a front-to-back acting force is first applied to the first trigger key 7 to move the first trigger key 7 to the first trigger position, and when continuing to press the trigger key assembly, a front-to-back acting force is applied to the second trigger key 8 to move the second trigger key 8 backward.
[0070] Specifically, when the first trigger key 7 is pressed to the first trigger position, the first trigger point 71 installed on the rear side of the first trigger key 7 contacts the second trigger point 72 installed on the second bracket 10, so that the fixed magnet 31 is powered on to generate a magnetic force and drive the moving magnet 1 to move forward to the first position, and the moving push rod 2 is clamped by the first clamping member 5. When the fixed magnet 31 is powered on, it can be instantaneously powered on. For example, it can be powered off after maintaining for 1-3 seconds first, that is, when the moving push rod 2 is clamped by the first clamping member 5, the fixed magnet 31 is powered off.
[0071] Among them, a spring is provided inside the first trigger key 7. After being pressed, the spring is compressed and pushes the first trigger point 71 to move to a position where it is connected to the second trigger point 72, and the first trigger key 7 can still be continuously pressed backward.
[0072] After the moving push rod 2 is clamped by the first clamping member 5, when the first trigger key 7 is continuously pressed, at this time, the pressing force will press on the surface of the second trigger key 8. When the second trigger key 8 moves backward to the second trigger position under the pressing force, the third trigger point 81 on its rear side contacts the fourth trigger point 82 installed on the second bracket 10, and the fixed magnet 31 is powered on again. At this time, since the moving push rod 2 is still limited by the first clamping member 5, the moving assembly is not unlocked and still remains in the first position.
[0073] After that, when the second trigger key 8 is continuously pressed, the rear end surface 83 of the second trigger key in contact with the rear end of the swing rod 9 moves backward, driving the swing rod 9 to rotate around the swing rod axis 90. Since the front end of the swing rod 9 contacts the first clamping horizontal end 52, the rotation of the swing rod 9 causes the front end of the swing rod 9 to push the first clamping member 5 downward, and the first clamping enabling end 51 moves out of the push rod slot 21 and is unlocked. At this time, since the fixed magnet 31 is in the powered-on state, the moving magnet 1 pushes the moving push rod 2 to continue moving forward to the second position.
[0074] It can be understood that here the first trigger key 7 is arranged in a way that it passes through the second trigger key 8 in the front-back direction. By reasonably setting each trigger point and the swing rod 9, the operator only needs to press one place with a finger, that is, by continuously pressing, the power-on of the fixed magnet 31 and the unlocking of the moving assembly are triggered successively, thereby realizing the two-stage advancement of the moving assembly to the first position and the second position, which greatly facilitates the operation of personnel.
[0075] See Figure 4 , Figure 4 , which is a schematic diagram of a multi-stage pushing device and its partial enlargement. When the moving magnet 1 moves from the first position to the second position, the magnet limiting portion 15 in the moving magnet 1 abuts against the first limiting portion 13 on the second bracket 10 to limit the forward displacement of the moving magnet 1, and the moving magnet 1 reaches the second position. At this time, the second clamping member 6 pops out under the action of the second clamping elastic member 63 to form a limit.
[0076] When the unlocking member 4 is pressed downward, the first unlocking portion 41 and the second unlocking portion 42 respectively push the first clamping horizontal end 52 and the second clamping horizontal end 62 downward to unlock the moving assembly. After that, the elastic member 12 drives the moving magnet 1 and the moving push rod 2 to rebound and reset. When the magnet baffle 11 abuts against the second limiting portion 14 on the second bracket 10 backward, the moving push rod 2 retracts to the initial position.
[0077] It should be noted that after the moving component is unlocked, the moving push rod 2 can directly return to the initial position at once. However, as a preferred method, the moving push rod 2 can also return to the initial position gradually in two steps. That is, when the moving push rod 2 is in the second position and the moving component is unlocked, when the moving push rod 2 moves backward to the first position, the moving component is locked again; then, when the moving component is unlocked again, the moving push rod 2 moves backward to the initial position to reset.
[0078] Exemplarily, referring to Figure 3 , the upper end surface of the second clamping horizontal end 62 is arranged higher than the upper end surface of the first clamping horizontal end 52, and / or the lower end surface of the second unlocking part 42 is arranged higher than the lower end surface of the first unlocking part 41, so that when the unlocking part 4 is pressed downward, the second unlocking part 42 first contacts the second clamping horizontal end 62 and pushes it downward, and the second clamping part 6 first releases the limit on the moving magnet 1, causing the moving magnet 1 to move backward and synchronously driving the moving push rod 2 to move backward.
[0079] When the moving push rod 2 moves backward to the first position, the first clamping enabling end 51 is reinserted into the push rod slot 21, locking the moving component again. Then, the unlocking part 4 can be continuously pressed downward, so that the first unlocking part 41 contacts the first clamping horizontal end 52 and pushes it downward, so that the first clamping enabling end 51 is removed from the push rod slot 21, the moving component is unlocked again, and the moving push rod 2 moves backward to the initial position to reset.
[0080] In summary, the multi-stage propulsion device of the present application realizes at least two-stage and phased propulsion through a one-stop key, and through intermittent electronic control, can perform continuous propulsion of the first stroke distance and the second stroke distance, overcoming the limitation of the single stroke distance movement of the electromagnetic device carrying an object, and the operator can operate the first trigger key 7 and the second trigger key 8 with one hand holding the second bracket 10 and one finger, with a compact and simple structure and convenient operation.
[0081] It should be understood that the specific embodiments described above are only used to explain the present application, and the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application, according to the technical solution and concept of the present application, makes changes, replacements, and combinations, and should be covered within the protection scope of the present application.
Claims
1. A multi-stage propulsion device, comprising a moving component capable of moving in a first direction; characterized in that: The moving component includes a moving magnet and a moving push rod connected to each other; During the first-stage propulsion, the moving magnet pushes the moving push rod to move from an initial position in the first direction to a first position, and the moving component is locked; During the second-stage propulsion, the moving component is unlocked, and the moving magnet further pushes the moving push rod to move in the first direction to a second position, and the moving component is locked again.
2. The multi-stage propulsion device according to claim 1, characterized in that: When the moving push rod is at the second position and the moving component is unlocked, the moving push rod can retreat in the opposite direction of the first direction to the first position, and the moving component is locked; After that, when the moving component is unlocked again, the moving push rod can retreat in the opposite direction of the first direction to the initial position.
3. The multi-stage propulsion device according to claim 1, characterized in that: It includes a first trigger key and a second trigger key; When the first trigger key is pressed to a first trigger position, the moving magnet drives the moving push rod to move to the first position; When the second trigger key is pressed to a second trigger position, the moving component is unlocked, and the moving magnet drives the moving push rod to move to the second position.
4. The multi-stage propulsion device according to claim 3, characterized in that: The second trigger key is arranged more rearward than the first trigger key in the pressing direction; Thus, after the first trigger key is pressed to the first trigger position, continuously pressing the first trigger key can touch and press the second trigger key.
5. The multi-stage propulsion device according to claim 3 or 4, characterized in that: After the second trigger key is pressed to the second trigger position, continuously pressing the second trigger key, and then unlocking the moving component through a transmission mechanism.
6. The multi-stage propulsion device according to claim 5, characterized in that: The multi-stage propulsion device includes a first clamping member extending along a direction intersecting the first direction; the moving push rod includes a push rod clamping groove; When the moving push rod moves to the first position, the first clamping member is clamped with the push rod clamping groove.
7. The multi-stage propulsion device according to claim 6, characterized in that: The multi-stage propulsion device includes a second clamping member extending along a direction intersecting the first direction; When the moving push rod moves to the second position, the second clamping member is clamped with the moving magnet.
8. The multi-stage propulsion device according to claim 7, characterized in that: The moving component includes a fixed magnet sleeved on the outer periphery of the moving magnet; the fixed magnet is fixed to a first bracket; An elastic member is connected between the moving magnet and the fixed magnet; When the moving magnet moves in the first direction, the elastic member deforms and stores energy; When the moving component is unlocked at the second position, the elastic member pushes the moving magnet and the moving push rod to rebound and reset in the opposite direction of the first direction.
9. The multi-stage propulsion device according to claim 8, characterized in that: It includes an unlocking member capable of moving along a direction intersecting the first direction, and the unlocking member has a first unlocking portion and a second unlocking portion capable of abutting against the first engaging member and the second engaging member respectively; When the moving magnet is located at the second position, the unlocking member is pushed to cause the first unlocking portion and the second unlocking portion to respectively push the first engaging member and the second engaging member to move, thereby unlocking the moving assembly.
10. The multi-stage propulsion device according to claim 6, characterized in that: The transmission mechanism is arranged as a swing rod capable of rotating around a swing rod axis; one end of the swing rod is close to the first engaging member and the other end is close to the second trigger key; After pressing the second trigger key to the second trigger position, continue to press the second trigger key to make the second trigger key abut against one end of the swing rod away from the first engaging member and drive the swing rod to rotate, so that one end of the swing rod close to the first engaging member pushes the first engaging member to move and disengages from the push rod slot, thereby unlocking the moving assembly.
11. The multi-stage propulsion device according to claim 6, characterized in that: The first engaging member is connected with a first engaging elastic member; In the initial state, the first engaging elastic member is in a state of storing energy; When the moving push rod moves to the first position, the first engaging elastic member pushes the first engaging member into the push rod slot to limit the displacement of the moving push rod.
12. The multi-stage propulsion device according to claim 7, characterized in that: The second engaging member is connected with a second engaging elastic member; In the initial state, the second engaging elastic member is in a state of storing energy; When the moving push rod moves to the second position, the second engaging elastic member pushes the second engaging member into a predetermined position to limit the displacement of the moving push rod.
13. The multi-stage propulsion device according to claim 1, characterized in that: It includes a first limiting portion and a second limiting portion arranged at intervals along the first direction; When the moving magnet moves to the second position, the first limiting portion abuts against the moving magnet to limit its displacement along the first direction; When the moving magnet retreats to the initial position, the second limiting portion abuts against the moving magnet to limit its displacement in the opposite direction of the first direction.