Data acquisition terminal compatible with multiple types of sensor interfaces

Abstract

The invention discloses a data acquisition terminal compatible with multiple types of sensor interfaces, and relates to the field of data acquisition terminals. The data acquisition terminal compatible with the multiple types of sensor interfaces comprises a data acquisition terminal main body and a protection unit. According to the data acquisition terminal compatible with the multiple types of sensor interfaces, after the plug seat and the sensor wiring port are plugged, the protective seat is loosened, the protective seat is pushed to slide downwards along the sliding rod under the rebound of the spring, and at the moment, the protective seat extrudes the plug seat and limits the plug seat, so that the situation that the plug seat is pulled out due to mistaken touch is avoided, and the service life of the plug seat is prolonged. And meanwhile, the plug seat is positioned in the protection seat, so that the plug seat and the sensor wiring port are protected, and the problem of faults caused by connection looseness, mistaken touch and damage of the plug seat and the sensor wiring port is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of data acquisition terminals, and in particular to a data acquisition terminal compatible with multiple types of sensor interfaces. Background Art

[0002] A data acquisition terminal refers to a portable or fixed device with multiple functions such as data acquisition, storage, transmission, and processing. It can collect data from various data sources.

[0003] The design of a data acquisition terminal compatible with multiple types of sensor interfaces needs to take into account the different output interfaces and communication protocols of various sensors to ensure wide access and accurate data collection. In the prior art, the data acquisition terminal sets each sensor wiring port according to the corresponding instrument type connected, but the sensor wiring port is directly exposed to the outside world, and the stability of the sensor wiring port cannot be guaranteed. When the connection between the plug socket and the sensor wiring port is loose, accidentally touched, or damaged, an abnormal alarm will occur during operation, and manual abnormal troubleshooting is required. Only after the fault is troubleshooted can it be used normally. Therefore, we propose a data acquisition terminal compatible with multiple types of sensor interfaces. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a data acquisition terminal that is compatible with multiple types of sensor interfaces, which solves the problem that the data acquisition terminal needs to set each sensor wiring port according to the type of corresponding instrument connected, but the sensor wiring port is directly exposed to the outside world, and the stability of the sensor wiring port plugging cannot be guaranteed. When the connection between the plug socket and the sensor wiring port is loose, accidentally touched or damaged, abnormal alarms will be caused during operation, and manual abnormal troubleshooting is required. Normal use can only be performed after the fault is eliminated.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: a data acquisition terminal compatible with multiple types of sensor interfaces includes a data acquisition terminal body, and the data acquisition terminal body is provided with:

[0006] A network port, which is arranged on the back of the data acquisition terminal body and is used for connecting to Ethernet;

[0007] A wiring port, which is arranged on the back of the data acquisition terminal body, and the wiring port includes an upper wiring terminal and a lower wiring terminal;

[0008] A display unit, which is arranged on the top end surface of the data acquisition terminal body and is used to display data and parameters;

[0009] A plurality of sensor connection ports are arranged on the data acquisition terminal body, and the sensor connection ports are used to connect to the monitoring instrument;

[0010] The data acquisition terminal body is provided with a protection unit, which is arranged on the sensor wiring port and is used to limit the plug socket plugged into the sensor wiring port.

[0011] Preferably, a USB interface is provided on the back of the data acquisition terminal body, and the USB interface is used to configure parameters of the data acquisition terminal body, download historical data through a USB flash drive, and upgrade the program.

[0012] Preferably, a manual ratio measurement port is provided on the back of the data acquisition terminal body, and the manual ratio measurement port is used for manual debugging of the data acquisition terminal body.

[0013] Preferably, an LED status light is provided on the top end surface of the data acquisition terminal body.

[0014] Preferably, there are four LED status lights, namely RUN, READ, DATA and USB.

[0015] Preferably, the top end surface of the data acquisition terminal body is provided with buttons, and the buttons are used for system startup and system data setting.

[0016] Preferably, the protection unit comprises:

[0017] A protective seat, which is located above the plurality of sensor wiring ports;

[0018] A mounting groove is provided on the protective seat, and the mounting groove is provided corresponding to the sensor wiring port;

[0019] A plurality of sliding rods are symmetrically fixedly connected to the data acquisition terminal body, and the protection seat is slidably connected to the inner wall of the sliding rod.

[0020] Preferably, a nut is threadedly connected to the outer peripheral wall of the sliding rod, a spring is sleeved on the outer peripheral wall of the sliding rod, and two ends of the spring are fixedly connected to the protective seat and the nut respectively.

[0021] The present invention discloses a data acquisition terminal compatible with multiple types of sensor interfaces, which has the following beneficial effects:

[0022] 1. The data acquisition terminal compatible with multiple types of sensor interfaces, after the plug socket is connected to the sensor wiring port, the protective socket is released, and the protective socket is pushed to slide down along the sliding rod under the rebound of the spring. At this time, the protective socket squeezes the plug socket to limit the plug socket to avoid accidental touch, which causes the plug socket to be pulled out. At the same time, the plug socket is placed in the protective socket to protect the plug socket and the sensor wiring port to avoid loose connection, accidental touch and damage between the plug socket and the sensor wiring port.

[0023] 2. The data acquisition terminal compatible with multiple types of sensor interfaces sets the time for the general module to wait for the center's response after sending a number to the center. After the general module sends a number to the center, if the center does not respond within the set time, the general module will resend the message data again. If no response is received from the center, the general module will resend the message three times, record the fault, and continue to send the next message at the next sending time.

[0024] 3. The data acquisition terminal compatible with multiple types of sensor interfaces collects data in real time. It collects data of onboard Zhenxuan (frequency + temperature) sensor, onboard Zhenxuan (frequency) sensor, onboard differential resistance sensor, onboard potentiometer sensor, onboard 4-20mA sensor, and onboard 4-20mA sensor copper resistance, obtains sensor feedback data, and performs status comparison and analysis through the comparison module. If the actual parameters are within the allowable threshold range, data is recorded for normal operation. If the actual parameters are lower or higher than the allowable threshold range, the operation is stopped at the specified time, and abnormal data is recorded. If the actual parameters are within the allowable threshold warning range, an early warning is issued, and abnormal data is recorded. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 This is a schematic diagram of the overall structure of this embodiment;

[0027] Figure 2 This is a schematic diagram of the sensor wiring port connection in this embodiment;

[0028] Figure 3 This is a schematic diagram of the structure of the back of the data acquisition terminal body of this embodiment;

[0029] Figure 4 This is a schematic diagram of the structure of the protection unit of this embodiment;

[0030] Figure 5This is a flow chart of the wiring port plugging in this embodiment;

[0031] Figure 6 This is a flow chart of determining the number of transmissions of the general module in this embodiment;

[0032] Figure 7 This is a data collection and comparison flow chart for this embodiment.

[0033] In the figure: 1. Data acquisition terminal body; 11. Network port; 12. USB port; 13. Manual ratio measurement port; 14. Wiring port; 15. Display unit; 16. LED status light; 17. Button; 18. Sensor wiring port; 2. Protection unit; 21. Protection seat; 22. Mounting slot; 23. Sliding rod; 24. Spring; 25. Nut. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] The embodiment of the present application provides a data acquisition terminal compatible with multiple types of sensor interfaces, thereby solving the problem that the data acquisition terminal needs to set each sensor wiring port 18 according to the type of corresponding instrument connected, but the sensor wiring port 18 is directly exposed to the outside world, and the stability of the sensor wiring port 18 cannot be guaranteed. When the connection between the plug socket and the sensor wiring port 18 is loose, accidentally touched or damaged, an abnormal alarm will occur during operation, and manual abnormal troubleshooting is required. Only after the fault is troubleshooted can the data acquisition terminal be used normally. After the plug socket and the sensor wiring port 18 are plugged in, the protective seat 21 is released, and the protective seat 21 is pushed to slide downward along the sliding rod 23 under the rebound of the spring 24. At this time, the protective seat 21 squeezes the plug socket and locks the plug socket to avoid accidental touch, which causes the plug socket to be pulled out. At the same time, the plug socket is placed in the protective seat 21 to protect the plug socket and the sensor wiring port 18, so as to avoid the problem that the connection between the plug socket and the sensor wiring port 18 is loose, accidentally touched or damaged and causes faults.

[0036] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0037] The embodiment of the present invention discloses a data acquisition terminal compatible with multiple types of sensor interfaces.

[0038] Embodiment 1:

[0039] According to the attached Figure 1-7 As shown, it includes a data acquisition terminal body 1, and the data acquisition terminal body 1 is provided with:

[0040] A network port 11 is provided on the back of the data acquisition terminal body 1 and is used for connecting to an Ethernet network;

[0041] A connection port 14 is provided on the back of the data acquisition terminal body 1, and the connection port 14 includes an upper connection terminal and a lower connection terminal;

[0042] The display unit 15 is arranged on the top end surface of the data acquisition terminal body 1 and is used to display data and parameters. The first line of the display unit 15 displays the time, the second line displays the device station address, the third line displays the IO port status, the fourth line displays the charging voltage and the door status, the fifth line displays the clock voltage and the switch value, and the sixth line displays the battery voltage and the DTU status.

[0043] A plurality of sensor connection ports 18, which are arranged on the data acquisition terminal body 1, and the sensor connection ports 18 are used to connect to the monitoring instrument;

[0044] Each sensor connection port 18 can be connected to vibrating string instruments, differential resistance instruments, potentiometer instruments, standard RS485 type instruments, standard current 0-20m, voltage signal and other types of instruments, covering the main types of sensors used in the field of dam safety monitoring;

[0045] It should be emphasized that the dam detection sensor terminals are not allowed to be connected at intervals. After the detection interval connection, a fault warning will be issued. Interval connection will cause a series of problems, including:

[0046] Unstable signal transmission: Intermittent connection may cause interference or attenuation of the signal during transmission, thus affecting the accuracy and reliability of the data. This is extremely unfavorable for the dam safety monitoring system that requires high precision and real-time monitoring.

[0047] Increased risk of failure: Interval connections increase the number of connection points, thus increasing the possibility of failure. Each connection point is a potential source of failure. Once a failure occurs, it will directly affect the normal operation and data collection of the sensor.

[0048] Difficult maintenance: The interval connection makes the system maintenance more complicated and difficult. When a fault occurs, each connection point needs to be checked one by one, which increases the difficulty and time cost of maintenance.

[0049] Impact on the overall performance of the system: The dam safety monitoring system is a whole, and its various parts are interrelated and influence each other. If the terminals of the sensor are connected at intervals, it may have an adverse effect on the performance and stability of the entire system, reducing the overall reliability and safety of the system.

[0050] It is particularly disclosed that the multiple sensor connection ports 18 on the data acquisition terminal body 1 are not necessarily required to all be connected to the same type of instruments, and multiple types of instruments can be mixed and connected to the same module.

[0051] Vibrating string instruments include vibrating string piezometer, vibrating string rebar meter, vibrating string steel plate meter, vibrating string earth pressure meter, vibrating string displacement meter, vibrating string side seam meter, vibrating string multi-point displacement meter, etc.

[0052] The measuring instrument type is selected as vibrating wire type, and the measurement results are modulus and temperature.

[0053] Differential resistance instruments include differential resistance water level gauge, differential resistance steel bar gauge, differential resistance steel plate gauge, differential resistance earth pressure gauge, differential resistance displacement gauge, differential resistance side seam gauge, differential resistance multi-point displacement gauge, etc.

[0054] The measuring instrument type is selected as differential resistance, and the measurement results are resistance sum and resistance ratio.

[0055] Potentiometer instruments include potentiometer displacement meters, potentiometer water weir meters, potentiometer angle meters, etc.

[0056] It is particularly disclosed that the type of measuring instrument is selected as a displacement meter, and the measurement result is two voltage values, one is the full-scale voltage, and the other is the voltage represented by the current measured value. The current position of the sensor relative to the full-scale can be determined by the ratio of the two.

[0057] Furthermore, standard RS485 instruments include all sensors that use RS485 communication mode to transmit measurement results. The module for measuring such instruments needs to be set as RS-485 instrument and the module program needs to be written to complete the relevant measurement and decoding of the results.

[0058] Furthermore, the standard current is 0-20mA. This type of instrument is set to 0-20mA in the measurement module, and the measurement result is the actual current value.

[0059] It should be particularly emphasized that in actual use, each sensor connection port 18 of the data acquisition terminal body 1 needs to be set according to the type of the corresponding instrument connected. If it is not set in advance, the channel will be connected to the vibrating string sensor by default.

[0060] A protection unit 2 is provided on the data acquisition terminal body 1 . The protection unit 2 is provided on the sensor wiring port 18 . The protection unit 2 is used to limit the plug socket plugged into the sensor wiring port 18 .

[0061] A USB interface 12 is provided on the back of the data acquisition terminal body 1. The USB interface 12 is used to configure parameters of the data acquisition terminal body 1, download historical data through a USB flash drive, and upgrade the program.

[0062] The back of the data acquisition terminal body 1 is provided with an artificial ratio measurement port 13, which is used for artificial debugging of the data acquisition terminal body 1. The artificial debugging achieves the following effects:

[0063] Manual data verification and calibration: Manual comparison port 13 allows manual access to test equipment to perform real-time comparison and verification of automatically collected input signals. This process can detect abnormalities in sensors or transmission lines and ensure data accuracy;

[0064] Fault diagnosis and system debugging: Through the manual comparison test port 13, the automatic control logic can be bypassed, and analog signals can be directly injected into the module or the output status can be read, so as to quickly locate hardware faults such as channel damage and signal interference, and improve maintenance efficiency;

[0065] Enhanced system reliability: In automated monitoring scenarios, the manual comparison measurement port 13 provides a redundant verification mechanism to prevent misjudgments caused by software logic errors or hardware drift, forming a dual guarantee of "automatic monitoring + manual review";

[0066] Compatibility extension: For special equipment or non-standard protocol scenarios, the artificial ratio measurement port 13 supports custom signal access and conversion, and expands the module's adaptability to different types of external devices.

[0067] An LED status light 16 is provided on the top end surface of the data acquisition terminal body 1 .

[0068] There are four LED status lights 16, namely RUN, READ, DATA and USB.

[0069] Especially public, RUN: flashing yellow means the device is normal, READ: green is always on means the sensor parameters are being read, DATA: blue is always on means data is being sent, USB: the light is on means the USB is plugged in, the light is off means the USB is not plugged in.

[0070] A button 17 is provided on the top end face of the data acquisition terminal body 1. The button 17 is used for system startup and system data setting. By pressing the button 17, the display unit 15 is turned over to view the data and version information read from channels one to thirty-two. On the main page, press "ENT" to enter the system menu. Menu items can be selected using the button 17. Select "Parameter Setting" in the system menu item and press "ENT" to enter the parameter setting interface.

[0071] Embodiment 2:

[0072] According to the attached Figure 1-7 As shown, the protection unit 2 includes:

[0073] A protective seat 21, which is located above the plurality of sensor wiring ports 18;

[0074] A mounting groove 22, which is provided on the protection seat 21, and the mounting groove 22 is provided corresponding to the sensor wiring port 18;

[0075] A plurality of sliding rods 23 are symmetrically fixedly connected to the data acquisition terminal body 1, and the protection seat 21 is slidably connected to the inner wall of the sliding rod 23;

[0076] The outer wall of the sliding rod 23 is threadedly connected with a nut 25 , and the outer wall of the sliding rod 23 is sleeved with a spring 24 . The two ends of the spring 24 are fixedly connected to the protection seat 21 and the nut 25 respectively.

[0077] It should be emphasized that when connecting vibrating string instruments, differential resistance instruments, potentiometer instruments, standard RS485 instruments, and standard current 4-20mA instruments, the plug socket needs to be plugged into the corresponding sensor wiring port 18;

[0078] Furthermore, at this time, by pulling the protective seat 21 to slide along the sliding rod 23, the plug seat is placed in the installation groove 22, and the protective seat 21 is pulled upward, so that the plug seat can be plugged into the corresponding sensor wiring port 18;

[0079] Furthermore, the power input interface connectors of the universal module are all standard 3.81mm pitch plug sockets with consistent pin definitions, which facilitates universal plug-in of a variety of instruments.

[0080] Furthermore, when the protective seat 21 moves to compress the spring 24, when the plug socket and the sensor wiring port 18 are connected, the protective seat 21 is released, and the protective seat 21 is pushed to slide downward along the sliding rod 23 under the rebound of the spring 24. At this time, the protective seat 21 squeezes the plug socket to limit the plug socket to avoid accidental touch that causes the plug socket to be pulled out. At the same time, the plug socket is placed in the protective seat 21 to protect the plug socket and the sensor wiring port 18 to avoid loose connection, accidental touch and damage between the plug socket and the sensor wiring port 18, resulting in malfunctions.

[0081] Working principle: The universal module can be set to one-way self-reporting or two-way response, which is determined by the power-on mode of the wireless communication module. If the communication module is always powered on, it is a two-way response mode. If the communication module is set to self-report at the point and then power off after reporting data, it is a one-way self-reporting mode. The self-reporting measurement interval can be set.

[0082] Communication protocol: Set the protocol format for communication between the general module and the central station;

[0083] Sub-protocol: cooperate with the communication protocol to make some subordinate settings, and select HEX or ASCII encoding according to the main protocol format;

[0084] Bias time: prevents multiple stations from sending data at the same time, which causes channel conflicts. It is especially suitable for self-built networks of ultra-short wave radio stations. If data is sent at the same time, it will interfere with each other, causing the entire system to be paralyzed or seriously missing data, and the entire system cannot operate healthily. Different bias times are assigned to each station. Specifically, the general module will send data according to the set bias time at the top of the hour. By setting the bias time of each station to be different, the time for each general module to send data to the center can be staggered.

[0085] Synchronize the system time of all common modules to avoid the problem of simultaneous transmission, and ensure that the system time of the common modules is always consistent with the central Beijing time;

[0086] Response time: Set the time the universal module waits for the center to respond after sending a message to the center. If the center does not respond within the set time after sending a message to the center, the universal module will resend the message data. If the center does not respond, it will resend the message three times, record the fault, and continue to send the next message at the next sending time.

[0087] Even Receipt: This setting is for when the message is too long and needs to be split into multiple packets for sending, whether each packet needs a central reply;

[0088] Even interval: If the sub-packet does not require the center to respond, then set the interval for the general module to automatically send sub-packets; the center must respond when the general module sends the last sub-packet;

[0089] Communication password: Set the password used in the message when the universal module of the measuring station communicates with the central station. The password value is sent to the judgment module. If the judgment module and the center are consistent, communication is carried out. If the judgment module and the center are inconsistent, the judgment leads to unsuccessful communication. The judgment sets the number of times. If the judgment number is exceeded, an early warning is issued.

[0090] Heartbeat function: Enable the function of the general module sending heartbeat when the DTU is online. The heartbeat is sent to keep the DTU online.

[0091] Heartbeat interval: set the time interval for heartbeat reports;

[0092] Acquisition channel setting: real-time data acquisition, collect the onboard Zhenxuan (frequency + temperature) sensor, onboard Zhenxuan (frequency) sensor, onboard differential resistance sensor, onboard potentiometer sensor, onboard 4-20mA sensor, onboard 4-20mA sensor copper resistance data, obtain sensor feedback data, and perform status comparison and analysis through the comparison module. If the actual parameters are within the allowable threshold range, data will be recorded for normal operation. If the actual parameters are lower or higher than the allowable threshold range, the operation will be stopped at the specified time, and abnormal data will be recorded; if the actual parameters are within the allowable threshold warning range, an early warning will be issued, and abnormal data will be recorded.

[0093] Communication mode: Set the communication mode of the main channel, select direct cable connection, set the main channel communication baud rate, please select it according to the actual situation and make it consistent with the external DTU, select the parity check according to the hardware requirements, and the preheating time is the preheating time from the standby channel device to the available power supply.

[0094] Upload parameters, click "Upload parameters" to configure the above-set parameters to the MCU device. If the upload fails, please click the "Upload to universal module" button again to upload. If multiple uploads fail, save the parameters locally, then exit to check the USB line, etc. When the line is repaired, import the parameters from the local, and then upload them to the universal module without having to set them again.

[0095] Built-in DTU settings are used to configure Ethernet in MUC.

[0096] Save the parameters to the local computer. When setting up the common modules of similar stations, export the parameters of the typical settings from the local computer, and then modify only the necessary parts and upload them to the common modules later, saving workload and ensuring the consistency and reliability of parameter settings.

[0097] At the same time, it serves as a backup of working materials to facilitate inspection when there is a problem with the station data. When the universal module of the station is replaced or repaired, the original set of parameters of the station can be directly imported and uploaded to the new universal module. This not only simplifies the technical requirements and workload of maintenance, but also further ensures the consistency of parameters and the reliability of equipment.

[0098] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A data acquisition terminal compatible with multiple types of sensor interfaces, comprising a data acquisition terminal body (1), characterized in that: The data acquisition terminal body (1) is provided with: A network port (11) is arranged on the back of the data acquisition terminal body (1), and the network port (11) is used for Ethernet connection; A wiring port (14) is arranged on the back of the data acquisition terminal body (1), and the wiring port (14) comprises an upper wiring terminal and a lower wiring terminal; A display unit (15), which is arranged on the top end surface of the data acquisition terminal body (1) and is used to display data and parameters; A plurality of sensor connection ports (18) are arranged on the data acquisition terminal body (1), and the sensor connection ports (18) are used to connect to monitoring instruments; The data acquisition terminal body (1) is provided with a protection unit (2), the protection unit (2) is provided on the sensor connection port (18), and the protection unit (2) is used to limit the plug socket plugged into the sensor connection port (18).

2. The data acquisition terminal compatible with multiple types of sensor interfaces according to claim 1, characterized in that: A USB interface (12) is provided on the back of the data acquisition terminal body (1), and the USB interface (12) is used to configure parameters of the data acquisition terminal body (1), download historical data through a USB flash drive, and upgrade programs.

3. The data acquisition terminal compatible with multiple types of sensor interfaces according to claim 1, characterized in that: A manual comparison measurement port (13) is provided on the back of the data acquisition terminal body (1), and the manual comparison measurement port (13) is used for manual debugging of the data acquisition terminal body (1).

4. The data acquisition terminal compatible with multiple types of sensor interfaces according to claim 1, characterized in that: The top end surface of the data acquisition terminal body (1) is provided with an LED status light (16).

5. The data acquisition terminal compatible with multiple types of sensor interfaces according to claim 1, characterized in that: The LED status lights (16) are provided with four, namely RUN, READ, DATA and USB.

6. The data acquisition terminal compatible with multiple types of sensor interfaces according to claim 1, characterized in that: The top end surface of the data acquisition terminal body (1) is provided with a button (17), and the button (17) is used for system startup and system data setting.

7. The data acquisition terminal compatible with multiple types of sensor interfaces according to claim 1, characterized in that: The protection unit (2) comprises: A protective seat (21) located above the plurality of sensor wiring ports (18); A mounting groove (22) is provided on the protective seat (21), wherein the mounting groove (22) is provided corresponding to the sensor wiring port (18); A plurality of sliding rods (23) are symmetrically fixedly connected to the data acquisition terminal body (1), and the protection seat (21) is slidably connected to the inner wall of the sliding rod (23).

8. The data acquisition terminal compatible with multiple types of sensor interfaces according to claim 7, characterized in that: The outer wall of the sliding rod (23) is threadedly connected with a nut (25), and the outer wall of the sliding rod (23) is sleeved with a spring (24), and the two ends of the spring (24) are respectively fixedly connected to the protective seat (21) and the nut (25).

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