Independent smoke detector transceiver with optional wireless module
Through modular design and custom communication protocols, users can flexibly select or replace wireless modules, solving the problem of the built-in module of existing wireless smoke detectors, and achieving high flexibility and low operation and maintenance costs of smoke detectors.
Patent Information
- Application Number
- CN202421984721.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-16
- Publication Date
- 2025-06-24
- Estimated Expiration
- 2034-08-16
AI Technical Summary
The existing wireless smoke detector cannot be flexibly selected or upgraded due to the built-in fixed wireless module, which limits the universality and expansion of the detector. The built-in module may be outdated due to technical iteration, increasing user maintenance costs. A single module is not suitable for all network environments, affecting the stability and reliability of data transmission.
An independent smoke detector transceiver device with optional wireless modules was designed. Through modular design, users can select or replace different types of wireless modules according to their needs to adapt to different network environments and application scenarios. The radio frequency module and the onboard antenna are integrated on the same circuit board. The antenna adopts onboard design. The modules are contacted through metal shrapnel and are connected to the smoke detector main body using a custom single-line communication protocol interface.
The flexibility and expansion of smoke detectors are realized, the wireless module outdated caused by technical iteration is avoided, and the user maintenance costs are reduced. The modular design makes repairs or replacement more convenient and faster, reducing the overall operation and maintenance costs.
Smart Images
Figure CN223022755U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of wireless communication, and particularly to a transceiver device of an independent smoke detector with an optional wireless module. Background Technique
[0002] In the field of fire safety, as a key device for early fire warning, the performance and reliability of smoke detectors are directly related to the safety of people's lives and property. Most of the smoke detectors widely used in the market at present adopt wired connection methods, and are connected to the central control system through preset cables to realize signal transmission and alarm. Although this method is stable and reliable, it has obvious deficiencies in terms of installation, maintenance and flexibility. Especially when retrofitting old buildings or deploying in temporary places, the wiring cost is high and the difficulty is great.
[0003] In recent years, with the rapid development of Internet of Things technology, wireless communication technology has been gradually introduced into fire-fighting equipment in order to solve the limitations of wired connection. However, most of the existing wireless smoke detectors adopt the design of built-in fixed wireless modules. Although this design realizes wireless transmission, there are the following problems: First, the wireless module cannot be flexibly selected or upgraded according to specific application scenarios, which limits the versatility and expandability of the detector; Second, the built-in wireless module may become quickly outdated due to the rapid technological iteration, increasing the later maintenance cost of users; Third, a single wireless module may not be applicable to all network environments, affecting the stability and reliability of data transmission. Content of the Utility Model
[0004] The utility model provides a transceiver device of an independent smoke detector with an optional wireless module to solve the technical problems raised in the above background technique.
[0005] To solve the above technical problems, the utility model discloses a transceiver device of an independent smoke detector with an optional wireless module, including: a PCB main body module, a first decorative part, and a second decorative part. The first decorative part and the second decorative part are detachably connected. The PCB main body module is arranged between the first decorative part and the second decorative part, and the first decorative part is detachably connected to the smoke detector main body;
[0006] The PCB main body module includes: a PCB board, an on-board antenna, and a radio frequency module. The on-board antenna is formed by a circuit etched on the PCB board. The radio frequency module is arranged on the PCB board. The radio frequency module is electrically connected to the on-board antenna. The radio frequency module is provided with interface pins, and the interface pins are connected to an interface that matches the smoke detector main body.
[0007] Preferably, the detachable connection is snap connection or screw connection.
[0008] Preferably, the on-board antenna includes:
[0009] A feeder stub, a first antenna body, a second antenna body, a third antenna body, and a fourth antenna body that are electrically connected in sequence.
[0010] Preferably, clearance is made around the feeder stub, the first antenna body, the second antenna body, the third antenna body, and the fourth antenna body on the PCB.
[0011] Preferably, the length of the feeder stub is 6.95 mm and the width is 0.8 mm. The feeder stub is led out from the RF module and routed to the clearance area at the front edge of the PCB. The feeder stub is routed in the direction opposite to the reference ground.
[0012] The length of the first antenna body is 6.95 mm and the width is 1.35 mm. The first antenna body is routed perpendicular to the feeder stub and continues to be routed along the edge of the PCB, taking the antenna body away from the reference ground.
[0013] The length of the second antenna body is 17 mm and the width is 1.35 mm. The second antenna body is routed at a perpendicular angle to the first antenna body, passes through the entire PCB and reaches the edge of the rear PCB. The routing direction of the second antenna body is parallel to the PCB reference ground.
[0014] The length of the third antenna body is 28.59 mm and the width is 1.35 mm. The third antenna body is routed along the edge of the PCB to the left end of the PCB. The third antenna body is in the opposite direction to the reference ground.
[0015] The length of the fourth antenna body is 16.4 mm and the width is 1.3 mm. It is routed along the left side edge of the PCB.
[0016] Preferably, the RF module includes a transmitting module and a receiving module.
[0017] Next, through the drawings and embodiments, the technical solution of the present invention will be further described in detail.
[0018] Compared with the prior art, the present invention has the following beneficial effects:
[0019] The overall structure of the independent smoke detector transceiver device of the present utility model is designed to be separable from the main body of the smoke detector. Through modular design (the independent smoke detector transceiver device is a wireless module), a separable design is adopted in the main body structure of the smoke detector for the wireless module (the independent smoke detector transceiver device). The wireless module is a pluggable component that makes contact through metal shrapnel and is connected to the main body of the smoke detector using a custom single-wire communication protocol interface. Users can select or replace different types of wireless modules (such as custom protocol ICs, Zigbee, LoRa, NB-IoT, etc.) according to actual needs, thereby adapting to different network environments and application scenarios. When the independent smoke detector transceiver device of the present utility model is used as a pure independent device, it has an aesthetically pleasing outer cover.
[0020] High flexibility: Users can flexibly select or replace wireless modules according to actual needs, meeting the requirements of different network environments and application scenarios, and improving the versatility and expandability of the detector.
[0021] Good cost-effectiveness: It avoids the problem of wireless module obsolescence caused by technological iteration, reducing the later maintenance cost for users. At the same time, the modular design makes repair or replacement more convenient and fast, reducing the overall operation and maintenance cost. Description of the Drawings
[0022] The drawings are used to provide a further understanding of the present utility model and constitute a part of the specification. Together with the embodiments of the present utility model, they are used to explain the present utility model and do not constitute a limitation to the present utility model. In the drawings:
[0023] Figure 1 It is a schematic structural diagram of the PCB main body module of the present utility model;
[0024] Figure 2 It is a schematic structural diagram of the on-board antenna of the present utility model;
[0025] Figure 3 It is an exploded structural diagram of the independent smoke detector transceiver device with an optional wireless module in an embodiment of the present utility model;
[0026] Figure 4 For the present utility model Figure 3 It is a schematic overall structural diagram of the independent smoke detector transceiver device with an optional wireless module in the present utility model;
[0027] Figure 5 For the present utility model Figure 4 It is a schematic structural diagram of the connection between the independent smoke detector transceiver device with an optional wireless module in the present utility model and the main body of the smoke detector;
[0028] Figure 6Schematic diagram of the connection structure of the first decorative part and the second decorative part in an embodiment of the present utility model;
[0029] Figure 7 is Figure 6 the enlarged structure diagram of area A in
[0030] In the figure: 1. PCB main body module; 1.1. RF module; 1.2. On-board antenna; 1.3. Interface pin; 1.4. PCB board; 2.1. Feed line stub; 2.2. First antenna main body; 2.3. Second antenna main body; 2.4. Third antenna main body; 2.5. Fourth antenna main body; 3. Matching structure; 31. First groove; 32. Second groove; 33. Vertical limit post; 34. Third groove; 35. Clamping block; 36. First spring; 37. Block; 38. Inclined surface; 39. Vertical column; 310. Connecting plate; 311. Second spring; 4. First decorative part; 41. Shell; 5. Second decorative part; 51. Shell cover; 6. Smoke detector main body; 7. Stand-alone smoke detector transceiver device with an optional wireless module. Specific embodiments
[0031] The following describes the preferred embodiments of the present utility model with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present utility model, and are not used to limit the present utility model.
[0032] In addition, in the present utility model, descriptions such as "first" and "second" are only for descriptive purposes, and do not particularly refer to the meaning of order or sequence, nor are they used to limit the present utility model. They are only used to distinguish components or operations described with the same technical terms, and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions and technical features between various embodiments can be combined with each other, but it must be based on the fact that those skilled in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present utility model.
[0033] The present utility model provides the following embodiments
[0034] Embodiment 1
[0035] The embodiment of the present utility model provides a stand-alone smoke detector transceiver device with an optional wireless module, as Figures 1 - 5As shown, there are a PCB main body module 1, a first decorative piece 4, and a second decorative piece 5. The first decorative piece 4 and the second decorative piece 5 are detachably connected. The PCB main body module 1 is arranged between the first decorative piece 4 and the second decorative piece 5, and the first decorative piece 4 is detachably connected to the smoke detector main body 6; the first decorative piece 4 and the second decorative piece 5 can be of various shapes. Figure 3 and Figure 6 are embodiments of different shapes.
[0036] The PCB main body module 1 includes: a PCB board 1.4, an on-board antenna 1.2, and a radio frequency module 1.1. The on-board antenna 1.2 is formed by a circuit etched on the PCB board 1.4. The radio frequency module 1.1 is arranged on the PCB board 1.4. The radio frequency module 1.1 is electrically connected to the on-board antenna 1.2. The radio frequency module 1.1 is provided with interface pins 1.3, and the interface pins 1.3 are connected to an interface that matches the smoke detector main body 6 for connection.
[0037] The radio frequency module 1.1 includes a transmitting module and a receiving module. The interface pins 1.3 are connected to an interface that matches the smoke detector main body 6, enabling the smoke detector main body 6 to communicate and network with other external smoke detection devices through the RF module to achieve data transmission and monitoring. A power management system is also designed inside the smoke detector main body 6 to provide a stable power supply for the RF module through the interface pins 1.3.
[0038] Specifically, the on-board antenna 1.2 includes:
[0039] A feeder stub 2.1, a first antenna body 2.2, a second antenna body 2.3, a third antenna body 2.4, and a fourth antenna body 2.5 that are electrically connected in sequence.
[0040] Preferably, clearance processing is performed around the feeder stub 2.1, the first antenna body 2.2, the second antenna body 2.3, the third antenna body 2.4, and the fourth antenna body 2.5 on the PCB board 1.4 to ensure the radiation efficiency of the antenna. At the beginning of the design of this structure, the hardware layout is made as compact as possible, which can save the PCB area to save costs and can also squeeze out a larger clearance area for the on-board antenna.
[0041] Specifically, the feed line stub 2.1 has a line length of 6.95 mm and a line width of 0.8 mm. The feed line stub 2.1 is led out from the RF module 1.1 and routes to the clearance area at the front board edge of the PCB board 1.4. In the embodiment of the present invention, the feed line stub 2.1 routes in the opposite direction of the reference ground and reaches the edge of the board structure to obtain a larger clearance and better antenna radiation directivity; the feed line stub 2.1 determines the overall antenna layout and the overall routing shape, and can be adjusted according to the actual size of the PCB board and the environmental clearance. The line width of the feed line stub 2.1 is 0.8, which matches the pad width of the RF module 1.1. This width structurally enables the entire antenna layout to strive for a larger overall clearance, and adjusts the width to adjust the impedance and bandwidth to obtain better return loss.
[0042] The first antenna body 2.2 has a line length of 6.95 mm and a line width of 1.35 mm. The first antenna body 2.2 routes perpendicular to the feed line stub 2.1 and continues to route along the board edge of the PCB board 1.4 to take the antenna body away from the reference ground to obtain better clearance; the width of this antenna part is 0.55 mm wider than the 0.8 mm routing width of the antenna feed line stub 2.1, which is used to adjust the bandwidth and impedance of the antenna, optimize the smith chart, and at the same time adjust the length of this antenna structure to optimize the antenna standing wave ratio, which determines the layout and shape of the subsequent antenna structures.
[0043] The second antenna body 2.3 has a line length of 17 mm and a line width of 1.35 mm. The second antenna body 2.3 routes at a perpendicular angle to the first antenna body 2.2 and passes through the entire PCB board 1.4 to reach the edge of the rear end of the PCB board 1.4. The routing direction of the second antenna body 2.3 is parallel to the PCB reference ground; the second antenna body 2.3 is the same as the first antenna body 2.2, maintaining this width in the case of a limited PCB board area to obtain a wider bandwidth, and at the same time leaving enough area to ensure that the routing length behind the antenna is sufficient to be tuned to the required operating frequency band; the relative distance between this routing and the reference ground is adjustable, which is used to optimize the antenna return loss, radiation efficiency, radiation direction, etc.
[0044] The third antenna body 2.4 has a line length of 28.59 mm and a line width of 1.35 mm. The third antenna body 2.4 routes along the edge of the PCB board 1.4 to the left end of the PCB board 1.4. The third antenna body 2.4 is in the opposite direction of the reference ground, and clearance is made around it. This section of routing enlarges the overall area and size of the antenna to obtain better radiation performance and better radiation directivity;
[0045] The fourth antenna body 2.5 has a line length of 16.4 mm and a line width of 1.3 mm, and routes along the left side edge of the PCB board 1.4. The routing length determines the final required operating frequency point.
[0046] The utility model provides a stand-alone smoke detector transceiver device with an optional wireless module. Through modular design, flexible selection and replacement of the wireless module are realized. At the same time, combined with intelligent identification and configuration technology, efficient and stable communication is ensured.
[0047] Intelligent identification and configuration: Through a custom single-wire communication method, it can automatically identify the type of the connected wireless module and automatically configure relevant parameters according to the module characteristics to achieve seamless docking and efficient communication.
[0048] Low-power management: Adopt advanced low-power design strategies, including sleep-wake mechanisms, dynamic power adjustment, etc., to ensure that the removable module can maximize the battery life after being inserted into the stand-alone smoke detector.
[0049] Security protection mechanism: Add security protection functions such as data encryption and authentication to ensure the access security of this wireless module.
[0050] Aiming at the deficiencies of the above-mentioned existing technologies, the utility model provides a stand-alone smoke detector transceiver device with an optional wireless module, aiming to provide a flexible, efficient and scalable fire warning solution.
[0051] The beneficial effects of the above technical solutions are as follows:
[0052] The stand-alone smoke detector transceiver device 7 with an optional wireless module of the utility model is integrally detachably designed from the smoke detector main body 6. Through modular design (the stand-alone smoke detector transceiver device 7 with an optional wireless module is a wireless module), in the structure of the smoke detector main body 6, a detachable design of the design and the wireless module (the stand-alone smoke detector transceiver device 7 with an optional wireless module) is realized. The wireless module is a pluggable component, and contact is achieved through metal shrapnel. It is connected to the smoke detector main body 6 through a custom single-wire communication protocol interface. Users can select or replace different types of wireless modules (such as custom protocol IC, Zigbee, LoRa, NB-IoT, etc.) according to actual needs, so as to adapt to different network environments and application scenarios. When the stand-alone smoke detector transceiver device 7 with an optional wireless module of the utility model is used as a pure stand-alone type, it has a beautiful outer cover.
[0053] High flexibility: Users can flexibly select or replace the wireless module according to actual needs, meet the requirements of different network environments and application scenarios, and improve the versatility and expandability of the detector.
[0054] Good cost-effectiveness: It avoids the problem of wireless module obsolescence caused by technological iteration, reduces the user's later maintenance cost. At the same time, the modular design makes maintenance or replacement more convenient and fast, reducing the overall operation and maintenance cost.
[0055] The antenna and the RF module 1.1 are integrated on the same circuit board to form an integrated structure. The antenna part adopts an on-board antenna design and is directly etched on the FR4 circuit board without external connection cables.
[0056] In Embodiment 2, on the basis of Embodiment 1, the detachable connection is a snap connection or a screw connection.
[0057] The beneficial effects of the above technical solutions are: The snap connection and the screw connection have the advantages of simple structure.
[0058] In Embodiment 3, on the basis of Embodiment 1, as Figure 6 、 Figure 7 shown, the first decorative member 4 is a housing 41, the second decorative member 5 is a housing cover 51, the PCB main module 1 is arranged in the housing 41, and the housing 41 and the housing cover 51 are detachably connected through a plurality of matching structures 3.
[0059] The plurality of matching structures 3 are arranged at intervals along the circumferential side of the housing 41. The matching structure 3 includes:
[0060] A first groove 31 and a second groove 32 are arranged at the top of the side wall of the housing cover 51 at an upper and lower interval;
[0061] A vertical limiting post 33 is integrally and fixedly arranged at the lower end of the housing cover 51. The vertical limiting post 33 is used to be inserted into the first groove 31 and the second groove 32. Two groups of third grooves 34 are symmetrically arranged on the left and right sides of the vertical limiting post 33;
[0062] Two groups of left and right symmetric clamping assemblies. The two groups of clamping assemblies correspond to the two groups of third grooves 34 one by one. The left clamping assembly includes: a clamping block 35. The clamping block 35 is slidably connected along the left and right directions to the upper inner wall of the left part of the second groove 32. The clamping block 35 is used to be connected to the corresponding third groove 34. A first spring 36 is fixedly connected between the clamping block 35 and the left inner wall of the third groove 34. A block 37 is integrally arranged at the lower left part of the clamping block 35. An inclined surface 38 with a lower left and a higher right is arranged on the right side of the block 37;
[0063] Two groups of vertical columns 39, corresponding to the two groups of blocks 37 one by one. The vertical columns 39 slidably penetrate through the lower end of the second groove 32 and the lower end of the housing 41 along the up and down direction. The upper end of the vertical column 39 contacts the inclined surface 38;
[0064] A connecting plate 310 is fixedly connected to the lower ends of the two groups of vertical columns 39. A second spring 311 is fixedly connected between the connecting plate 310 and the lower end of the housing 41.
[0065] The working principle and beneficial effects of the above technical solutions are:
[0066] When the utility model connects the connecting housing 41 and the housing cover 51: First, the upper pressing connecting plate 310 (the upper pressing connecting plate 310 can be manually pressed, or the connecting plate 310 is placed at the upper end of the table, and under the action of the gravity of the housing 41, the connecting plate 310 moves upward), driving the corresponding vertical column 39 to move upward. The upper end of the vertical column 39 cooperates with the inclined surface 38, so that the two groups of clamping blocks 35 of each matching structure move away from each other, and the area between the two groups of clamping blocks 35 is available for the vertical limiting column 33 to be inserted. After the vertical limiting column 33 is inserted, the connecting plate 310 is released, and the first spring 36 resets. As Figure 6 shown, the two groups of clamping blocks 35 are respectively pressed in the corresponding third grooves 34. At this time, the first spring 36 is in a compressed state, so that the clamping blocks 35 clamp the vertical limiting column 33, realizing the connection between the housing 41 and the housing cover 51.
[0067] The utility model avoids the inconvenience of using tools required for screw connection between the housing 41 and the housing cover 51, and at the same time avoids the easy damage or difficult disassembly of snap connection. The utility model can facilitate the synchronous connection of multiple vertical limiting columns 33, and the connection is convenient.
[0068] Obviously, those skilled in the art can make various changes and modifications to the present utility model without departing from the spirit and scope of the present utility model. Thus, if these modifications and variations of the present utility model fall within the scope of the claims of the present utility model and their equivalent technologies, the present utility model also intends to include these changes and modifications.
Claims
1. An independent smoke detector transceiver with an optional wireless module, characterized in that: include: A PCB main body module (1), a first decorative piece (4), and a second decorative piece (5), wherein the first decorative piece (4) and the second decorative piece (5) are detachably connected, the PCB main body module (1) is arranged between the first decorative piece (4) and the second decorative piece (5), and the first decorative piece (4) and the smoke detector main body (6) are detachably connected; The PCB main body module (1) comprises: a PCB board (1.4), an onboard antenna (1.2), and a radio frequency module (1.1); the onboard antenna (1.2) is formed by a circuit etched on the PCB board (1.4); the radio frequency module (1.1) is arranged on the PCB board (1.4); the radio frequency module (1.1) is electrically connected to the onboard antenna (1.2); the radio frequency module (1.1) is provided with an interface pin (1.3); the interface pin (1.3) is connected to an interface matching the smoke detector main body (6).
2. According to claim 1, a stand-alone smoke detector transceiver with an optional wireless module, characterized in that: The detachable connection is a snap connection or a screw connection.
3. The independent smoke detector transceiver device with optional wireless module according to claim 1, characterized in that: The onboard antenna (1.2) includes: A feed branch (2.1), a first antenna body (2.2), a second antenna body (2.3), a third antenna body (2.4), and a fourth antenna body (2.5) are electrically connected in sequence.
4. The independent smoke detector transceiver device with optional wireless module according to claim 3, characterized in that: Clearance treatment is performed around the feed branch (2.1), the first antenna body (2.2), the second antenna body (2.3), the third antenna body (2.4), and the fourth antenna body (2.5) on the PCB board (1.4).
5. The independent smoke detector transceiver device with optional wireless module according to claim 3, characterized in that: The feed branch (2.1) has a line length of 6.95 mm and a line width of 0.8 mm. The feed branch (2.1) is led out from the radio frequency module (1.1) and routed to the front end board edge clearance area of the PCB board (1.4). The feed branch (2.1) is routed in the opposite direction to the reference ground. The first antenna body (2.2) has a line length of 6.95 mm and a line width of 1.35 mm. The first antenna body (2.2) and the feed branch (2.1) are arranged perpendicularly. The first antenna body (2.2) continues to be arranged along the edge of the PCB board (1.4), so that the antenna body is away from the reference ground. The second antenna body (2.3) has a line length of 17 mm and a line width of 1.35 mm. The second antenna body (2.3) is arranged at a perpendicular angle to the first antenna body (2.2), passes through the entire PCB board (1.4) and reaches the edge of the PCB board (1.4) at the rear end. The routing direction of the second antenna body (2.3) is parallel to the PCB reference ground. The third antenna body (2.4) has a line length of 28.59 mm and a line width of 1.35 mm. The third antenna body (2.4) extends along the edge of the PCB board (1.4) to the left end of the PCB board (1.4). The third antenna body (2.4) is in the opposite direction to the reference ground. The fourth antenna body (2.5) has a line length of 16.4 mm and a line width of 1.3 mm, and is routed along the left side source of the PCB board (1.4).
6. The independent smoke detector transceiver device with optional wireless module according to claim 1, characterized in that: The radio frequency module (1.1) includes a transmitting module and a receiving module.
7. The independent smoke detector transceiver device with optional wireless module according to claim 1, characterized in that: The first decorative component (4) is a shell (41), the second decorative component (5) is a shell cover (51), the PCB main body module (1) is arranged in the shell (41), and the shell (41) and the shell cover (51) are detachably connected via a plurality of matching structures (3).
8. The independent smoke detector transceiver device with optional wireless module according to claim 7, characterized in that: A plurality of matching structures (3) are arranged at intervals along the circumference of the housing (41), and the matching structures (3) include: A first groove (31) and a second groove (32) are arranged at a vertical interval on the top of the side wall of the shell cover (51); A vertical limiting column (33) is integrally fixedly arranged at the lower end of the shell cover (51), the vertical limiting column (33) is used to be inserted into the first groove (31) and the second groove (32), and two groups of third grooves (34) are symmetrically arranged on the left and right sides of the vertical limiting column (33); Two groups of left-right symmetrical clamping assemblies, the two groups of clamping assemblies correspond to the two groups of third grooves (34) one by one, the clamping assembly on the left side comprises: a clamping block (35), the clamping block (35) is slidably connected to the inner wall of the left upper end of the second groove (32) along the left-right direction, the clamping block (35) is used to be connected to the corresponding third groove (34), a first spring (36) is fixedly connected between the clamping block (35) and the left inner wall of the third groove (34), a block body (37) is integrally arranged at the left lower end of the clamping block (35), and a slope (38) with a lower left side and a higher right side is arranged on the right side of the block body (37); Two groups of vertical columns (39) correspond to the two groups of blocks (37) respectively. The vertical columns (39) slide along the up-down direction to penetrate the lower end of the second groove (32) and the lower end of the shell (41). The upper end of the vertical column (39) contacts the inclined surface (38). The connecting plate (310) is fixedly connected to the lower ends of the two groups of vertical columns (39), and a second spring (311) is fixedly connected between the connecting plate (310) and the lower end of the housing (41).