An anti-freezing device for charging guns in alpine regions

Abstract

The present invention discloses an anti-freezing device for a charging gun in alpine regions, which relates to the technical field of charging guns. The present invention includes a plug, an end panel and a handle, and the plug is connected to the power receiving end through a buckle. Heating sheets are embedded in the unlocking button and the buckle movable plate of the device, and anti-freezing is achieved through a thermistor and a force-sensitive resistor. When low-temperature freezing occurs, pressing the unlocking button triggers the heating sheet to melt the ice, ensuring smooth plugging and unplugging; after the temperature recovers, the thermistor automatically cuts off the power to avoid energy waste. The dual force-sensitive resistors detect the frozen and unfrozen states, enhancing stability. The electromagnetic solenoid-assisted unlocking is combined with mechanical transmission to improve flexibility. The reset tension spring and the limiting convex block ensure the durability of the structure. The device effectively solves the problem of freezing of the charging gun in alpine environments, improving the use reliability and operation convenience.

Description

Technical Field

[0001] The present invention relates to the technical field of charging guns, and particularly to an anti-freezing device for a charging gun in alpine regions. Background Art

[0002] In alpine regions, as an important connecting component of electric equipment, the charging gun faces the problem of water condensing into ice in a low-temperature environment. The existing charging gun designs usually only include basic plug-and-unplug structures, such as simple plugs and buckle mechanisms, and the connection and separation with the power receiving end are achieved by manually pressing a button or pulling a lever. However, this design has significant defects in a cold environment. First, when the ambient temperature is lower than the condensation point, the moisture in the air will freeze at the plug or the unlocking button, resulting in the button being unable to be pressed or the buckle being unable to disengage, and it is difficult for the user to pull out the charging gun. Second, the existing technology lacks effective anti-freezing measures and usually relies on external heating devices or manual de-icing, which is cumbersome and inefficient. These disadvantages are particularly prominent in alpine environments, restricting the practicability and reliability of the charging gun. Summary of the Invention

[0003] To overcome the defects of the above-mentioned prior art, the present invention provides the following technical solution: An anti-freezing device for a charging gun in alpine regions, including a plug, the plug is fixedly installed on an end panel, rectangular through holes are opened on both the end panel and the plug, an electromagnet is fixedly installed in the rectangular through hole, two parallel buckle slide rods are fixedly installed on the side of the end panel away from the plug, a buckle movable plate is slidably installed on the buckle slide rods, and the buckle movable plate is also slidably arranged in the rectangular through hole, so that both ends of the buckle movable plate are located on both sides of the plug and the end panel respectively. A buckle is provided at one end of the buckle movable plate facing the plug, and the buckle is in clamping cooperation with the power receiving end; the end panel is fixedly installed on a mechanism box, the mechanism box is fixedly installed on a handle, a cable is arranged inside the handle, one end of the cable is electrically conductive with the plug, an unlocking button is slidably embedded and installed on the circumferential surface of the mechanism box along its radial direction, and the unlocking button is in transmission cooperation with the buckle movable plate; a second heating sheet and a first heating sheet are respectively embedded in the buckle movable plate and the unlocking button, a first force-sensitive resistor is arranged on the side of the unlocking button located outside the mechanism box for measuring the force of pressing the unlocking button; a thermistor is also embedded in the unlocking button or the buckle movable plate.

[0004] Preferably, the bottoms of the two buckle slide rods are fixedly connected to the end panel through a buckle slide rod bracket, and a return spring is wound around each buckle slide rod, and both ends of the return spring are fixedly connected to the buckle movable plate and the buckle slide rod bracket.

[0005] Preferably, two symmetrically arranged swing frame brackets are fixedly mounted on the snap slide bracket, and a swing frame is movably connected between the two swing frame brackets. A roller that contacts and rolls with the snap movable plate is rotatably mounted on one end of the swing frame. A slide rail groove is also provided on the swing frame, and a sliding pin rod is slidably mounted in the slide rail groove.

[0006] Preferably, a guide slide bracket is fixedly mounted on the snap slide bracket, two parallel guide slides are fixedly mounted on the guide slide bracket, and a toggle frame is slidably mounted on the two guide slides, wherein the sliding pin is fixedly mounted on the toggle frame.

[0007] Preferably, both guide slide rods are provided with sliding sleeves, the bottom ends of the two sliding sleeves are fixedly matched with the toggle frame, and the top ends of the two sliding sleeves are fixedly matched with the unlocking button, wherein a limiting protrusion is fixedly installed on the unlocking button, and the limiting protrusion is used to prevent the unlocking button from separating from the mechanism box.

[0008] Preferably, an auxiliary support plate is fixedly installed on the inner wall of the mechanism box, the auxiliary support plate is arranged parallel to the unlocking button, and an auxiliary guide slide rod parallel to the axis of the sliding sleeve is slidably installed on the auxiliary support plate, and a spring is arranged around the auxiliary guide slide rod, one end of the spring is fixedly connected to the unlocking button, and the other end of the spring is fixedly connected to the lower pressure plate, and the auxiliary guide slide rod is fixedly matched with the unlocking button.

[0009] Preferably, the lower pressure plate is slidably sleeved on the outer surface of the auxiliary guide slide bar, and a second force-sensitive resistor is provided between the opposite surfaces of the lower pressure plate and the auxiliary support plate, and the second force-sensitive resistor is used to detect the elastic force of the spring.

[0010] Preferably, it also includes a 3V DC power supply, a 5V DC power supply, and a 12V DC power supply; wherein a fixed resistor R3 and a second force-sensitive resistor are arranged in series in the 3V DC power supply, and an NPN transistor is arranged in parallel at both ends of the second force-sensitive resistor, the base of the NPN transistor is electrically connected to the positive end of the second force-sensitive resistor, and the emitter is electrically connected to the negative end of the second force-sensitive resistor, and the collector and emitter of the NPN transistor are connected in series in the 5V DC power supply.

[0011] Preferably, the 5V DC power supply is also provided with a fixed resistor R1, a first force-sensitive resistor, a fixed resistor R2, and a positive temperature coefficient thermistor in series; another NPN transistor is provided in parallel at both ends of the fixed resistor R2, the base of the NPN transistor is electrically connected to the positive end of the fixed resistor R2, and the emitter is electrically connected to the negative end of the fixed resistor R2, and the collector and emitter of the NPN transistor are connected in series in the 12V DC power supply.

[0012] Preferably, a relay is also connected in series in the 12V DC power supply. The open contacts of the relay are connected in series in the start-up circuits of the first heating element and the second heating element to control the on-off of the first heating element and the second heating element.

[0013] The present invention has the following beneficial effects compared with the prior art: (1) By embedding the first heating element and the second heating element in the unlocking button and the buckle movable plate and combining with the intelligent control circuit of the thermistor and the force-sensitive resistor, the present invention can quickly detect and melt the condensed ice in a low-temperature environment. When the ambient temperature is lower than the condensation point, the user presses the unlocking button to trigger the heating element to work, and the generated heat quickly thaws the frozen part, ensuring a smooth separation process between the charging gun plug and the power receiving end, avoiding the problem of being unable to pull out due to freezing, and thus significantly improving the reliability of charging equipment in alpine regions; (2) The present invention is internally provided with a positive temperature coefficient thermistor, which is linked with the control circuit of the heating element. When the unlocking button and the buckle movable plate are heated to a certain temperature, the resistance value of the thermistor increases, causing the relay to disconnect and the heating element to stop working. This intelligent temperature control mechanism ensures that heating only occurs when necessary, avoiding energy waste caused by long-term heating; (3) Through the dual-detection design of the first force-sensitive resistor and the second force-sensitive resistor, the device can respectively sense the pressing force when the unlocking button is frozen and the normal movement state when it is not frozen. When the unlocking button is frozen, the first force-sensitive resistor triggers heating; when it is not frozen, the second force-sensitive resistor detects through spring extrusion to ensure that the heating circuit does not start by mistake. This redundant design enhances the stability of the system and avoids misoperation or ineffective heating; (4) The present invention not only realizes the unlocking of the buckle through the mechanical transmission of the unlocking button, but also designs an electromagnet as an auxiliary unlocking means. At normal temperature, the magnetic force generated by the energized electromagnet can directly drive the movement of the buckle movable plate to complete the unlocking. This dual-mode design not only retains the intuitiveness of mechanical operation but also increases the efficiency of electromagnetic control, improving the operation flexibility and convenience of users in different scenarios; (5) The present invention adopts the combined design of a buckle slide rod and a reset tension spring to ensure that the buckle movable plate can automatically reset after unlocking, avoiding the buckle being in a detached state for a long time and affecting the next use. At the same time, the setting of the limit bump and the auxiliary guide slide rod prevents the unlocking button from detaching or shifting, ensuring the compactness of the structure and the overall durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic diagram of the overall structure of the present invention.

[0015] Figure 2 is Figure 1 a schematic diagram of the structure at A in

[0016] Figure 3 is a schematic diagram of the handle structure of the present invention.

[0017] Figure 4 for Figure 3 Schematic diagram of the structure at point B in the middle.

[0018] Figure 5 This is a structural diagram of the sliding sleeve of the present invention.

[0019] Figure 6 It is a structural schematic diagram of the swing frame of the present invention.

[0020] Figure 7 This is a structural schematic diagram of the snap-fit movable plate of the present invention.

[0021] Figure 8 This is the start-stop control diagram of the heating plate of the present invention.

[0022] In the figure: 101-handle; 102-cable; 103-mechanism box; 104-plug; 105-clip; 106-unlock button; 107-end panel; 108-auxiliary support plate; 109-spring; 110-down pressure plate; 111-second force-sensitive resistor; 112-sliding sleeve; 113-limiting protrusion; 114-auxiliary guide slide; 115-first heating plate; 116-guide slide; 117-sliding frame; 118-clip slide bracket; 119-clip slide; 120-clip movable plate; 121-reset spring; 122-swing frame bracket; 123-guide slide bracket; 124-swing frame; 125-electromagnet; 126-sliding pin; 127-slide groove; 128-roller; 129-second heating plate; 130-rectangular through hole. DETAILED DESCRIPTION

[0023] The following is combined with Figures 1 - 8 , and further illustrate the technical solution of the present invention through specific implementation methods.

[0024] The present invention provides an anti-freezing device for a charging gun in alpine regions, which includes a plug 104 fixedly installed on an end panel 107. Rectangular through holes 130 are provided on both the end panel 107 and the plug 104. An electromagnet 125 is fixedly installed in the rectangular through hole 130. On the side of the end panel 107 away from the plug 104, two parallel snap rod 119 are fixedly installed. A snap movable plate 120 is slidably installed on the snap rod 119. The snap movable plate 120 is also slidably arranged in the rectangular through hole 130, so that both ends of the snap movable plate 120 are located on both sides of the plug 104 and the end panel 107. A snap 105 is provided at one end of the snap movable plate 120 facing the plug 104, and the snap 105 is in snap-fit with the power receiving end; the end panel 107 is fixedly installed on a mechanism box 103, the mechanism box 103 is fixedly installed on a handle 101, a cable 102 is arranged inside the handle 101, and one end of the cable 102 is electrically conductive with the plug 104. An unlocking button 106 is slidably embedded and installed on the circumferential surface of the mechanism box 103 along its radial direction, and the unlocking button 106 is in transmission cooperation with the snap movable plate 120; a second heating sheet 129 and a first heating sheet 115 are respectively embedded in the snap movable plate 120 and the unlocking button 106. A first force-sensitive resistor is provided on the surface of the unlocking button 106 located outside the mechanism box 103 for measuring the pressing force of the unlocking button 106; a thermistor is also embedded in the unlocking button 106 or the snap movable plate 120. The bottoms of the two snap rod 119 are fixedly connected to the end panel 107 through a snap rod bracket 118. A reset tension spring 121 is arranged around each snap rod 119, and both ends of the reset tension spring 121 are fixedly connected to the snap movable plate 120 and the snap rod bracket 118. Two symmetrically arranged swing frame brackets 122 are fixedly installed on the snap rod bracket 118. A swing frame 124 is movably connected between the two swing frame brackets 122. A roller 128 in contact and rolling cooperation with the snap movable plate 120 is rotatably installed at one end of the swing frame 124. A slide rail groove 127 is also provided on the swing frame 124, and a sliding pin rod 126 is slidably installed in the slide rail groove 127. A guiding rod bracket 123 is also fixedly installed on the snap rod bracket 118. Two parallel guiding rods 116 are fixedly installed on the guiding rod bracket 123. A toggle frame 117 is slidably installed on the two guiding rods 116, and the sliding pin rod 126 is fixedly installed on the toggle frame 117. Sliding sleeves 112 are slidably sleeved on the two guiding rods 116. The bottoms of the two sliding sleeves 112 are fixedly fitted with the toggle frame 117, and the tops of the two sliding sleeves 112 are fixedly fitted with the unlocking button 106. A limit convex block 113 is fixedly installed on the unlocking button 106, and the limit convex block 113 is used to prevent the unlocking button 106 from separating from the mechanism box 103.An auxiliary support plate 108 is fixedly installed in the inner wall of the mechanism box 103 in an overhead manner. The auxiliary support plate 108 is arranged in parallel with the unlocking button 106. An auxiliary guiding slide bar 114 parallel to the axis of the sliding sleeve 112 is slidably installed on the auxiliary support plate 108. A spring 109 is wound around the auxiliary guiding slide bar 114. One end of the spring 109 is fixedly connected to the unlocking button 106, and the other end of the spring 109 is fixedly connected to a lower pressing plate 110. The auxiliary guiding slide bar 114 is fixedly matched with the unlocking button 106. The lower pressing plate 110 is slidably sleeved on the outer surface of the auxiliary guiding slide bar 114. A second force-sensitive resistor 111 is arranged between the opposite surfaces of the lower pressing plate 110 and the auxiliary support plate 108. The second force-sensitive resistor 111 is used to detect the elastic force of the spring 109.

[0025] It further includes a 3V DC power supply, a 5V DC power supply, and a 12V DC power supply. A fixed-value resistor R3 and a second force-sensitive resistor 111 are connected in series in the 3V DC power supply. And two ends of the second force-sensitive resistor 111 are connected in parallel with an NPN triode. The base of the NPN triode is electrically connected to the positive extreme of the second force-sensitive resistor 111, and the emitter is electrically connected to the negative extreme of the second force-sensitive resistor 111. And the collector and the emitter of the NPN triode are connected in series in the 5V DC power supply. A fixed-value resistor R1, a first force-sensitive resistor, a fixed-value resistor R2, and a positive temperature coefficient thermistor are connected in series in the 5V DC power supply. And two ends of the fixed-value resistor R2 are connected in parallel with another NPN triode. The base of the NPN triode is electrically connected to the positive extreme of the fixed-value resistor R2, and the emitter is electrically connected to the negative extreme of the fixed-value resistor R2. And the collector and the emitter of the NPN triode are connected in series in the 12V DC power supply. A relay is connected in series in the 12V DC power supply. The open contacts of the relay are connected in series in the start-up circuits of the first heating sheet 115 and the second heating sheet 129 for controlling the on-off of the first heating sheet 115 and the second heating sheet 129.

[0026] The working principle of an anti-freezing device for charging guns in alpine regions disclosed by the present invention is as follows: When the ambient temperature is normal, the user presses the unlocking button 106 normally. The unlocking button 106 drives the sliding sleeve 112 to move together. The sliding sleeve 112 drives the toggling frame 117 to slide on the guiding slide rod 116. Then, the toggling frame 117 toggles the swinging frame 124 to swing on the swinging frame bracket 122 through the sliding pin rod 126 (the sliding pin rod 126 also slides in the slide rail groove 127). The roller 128 on the swinging frame 124 will roll between the buckle movable plate 120, driving the buckle movable plate 120 to move towards the electromagnet 125. At this time, the buckle movable plate 120 slides on the buckle slide rod 119, and the reset tension spring 121 is in a stretched state. This process separates the buckle 105 from the bayonet of the power receiving end, and pulls out the plug 104 from the power receiving end or the charging pile (if the charging pile has the same bayonet design as the power receiving end). When the ambient temperature drops, moisture in the air will condense on the electromagnet 125 and the unlocking button 106. At this time, when the user presses the unlocking button 106, it may not be pressed (the unlocking button 106 is frozen together with the mechanism box 103). When the user presses the unlocking button 106, the resistance value of the first force-sensitive resistor on the unlocking button 106 will decrease, which will cause the potential difference across the fixed resistor R2 to increase (the voltage divided across the fixed resistor R2 becomes larger), making the potential difference across the fixed resistor R2 greater than 0.7V. At this time, there will be enough trigger voltage between the base and emitter of the NPN transistor connected in series in the 12V DC power supply, which will cause the open contact of the relay controlling the second heating sheet 129 and the first heating sheet 115 to close. At this time, the second heating sheet 129 and the first heating sheet 115 start to work and generate heat, melting the condensed ice around the unlocking button 106 and the buckle movable plate 120. At the same time, at normal temperature, the resistance value of the thermistor is relatively high, which will cause a relatively high potential difference across the thermistor. After the first force-sensitive resistor is pressed (pressing the unlocking button 106), the potential difference across the fixed resistor R2 cannot reach 0.7V. That is to say, the above situation will only occur when the ambient temperature (the actual temperature of the unlocking button 106 and the buckle movable plate 120) is lower than the air condensation point. At the same time, because the thermistor is in contact with the unlocking button 106, when the unlocking button 106 is heated, the resistance value of the thermistor will increase, resulting in a decrease in the potential difference across the fixed resistor R2. At this time, the collector and emitter of the NPN transistor connected in series to the 12V DC power supply are cut off, and the open contact of the corresponding relay is disconnected. The second heating sheet 129 and the first heating sheet 115 lose power and no longer heat the unlocking button 106 and the buckle movable plate 120.

[0027] When the ambient temperature is low, but the unlocking button 106 may still be pressed (not frozen), when the unlocking button 106 moves downward at this time, the unlocking button 106 will drive the auxiliary guiding slide bar 114 to move together, and the spring 109 wound around the auxiliary guiding slide bar 114 will also move together. At this time, the spring 109 will squeeze the second force-sensitive resistor 111 through the lower pressing plate 110, resulting in a decrease in the resistance value of the second force-sensitive resistor 111. That is to say, only when the unlocking button 106 can be pressed and moved, the second force-sensitive resistor 111 will be squeezed by the spring 109 (the description of the spring 109 squeezing the second force-sensitive resistor 111 here means that the squeezing force of the spring 109 on the second force-sensitive resistor 111 increases. Because after the spring 109 receives the pressure from the unlocking button 106, the deformation amount of the spring 109 increases, its own elastic force also increases, and the squeezing force on the second force-sensitive resistor 111 also increases). The decrease in the resistance value of the second force-sensitive resistor 111 will cause the potential difference across its own two ends to decrease. Therefore, the potential difference between the base and the emitter of the NPN transistor connected in series to the 5V DC power supply will be lower than 0.7V. At this time, the collector and the emitter of this NPN transistor are cut off, which will cause no current to pass through the circuit where the first force-sensitive resistor is located, so it cannot take effect, directly resulting in the corresponding second heating sheet 129 and the first heating sheet 115 not being able to work (no work is required at this time). And here the second force-sensitive resistor 111 can make the normally open contact of the relay disconnect, which has the same function as the thermistor making the normally open contact of the relay disconnect, and can also play a redundant setting.

[0028] In the normal temperature mode, the snap buckle movable plate 120 can also be driven to move by controlling the electromagnet 125. When the electromagnet 125 is energized, it will generate a magnetic force, and the magnetic force attracts the snap buckle movable plate 120 to move towards the electromagnet 125, and then drives the snap buckle 105 to move synchronously.

Claims

1. An anti-freezing device for a charging gun in alpine regions, characterized in that: It includes a plug (104) fixedly installed on an end panel (107). Rectangular through holes (130) are provided on both the end panel (107) and the plug (104). An electromagnet (125) is fixedly installed in the rectangular through hole (130). On the side of the end panel (107) away from the plug (104), two parallel snap slide rods (119) are fixedly installed. A snap movable plate (120) is slidably installed on the snap slide rod (119). The snap movable plate (120) is also slidably arranged in the rectangular through hole (130), so that both ends of the snap movable plate (120) are located on both sides of the plug (104) and the end panel (107). A snap (105) is provided at one end of the snap movable plate (120) facing the plug (104), and the snap (105) is in clamping fit with the power receiving end; The end panel (107) is fixedly installed on a mechanism box (103), and the mechanism box (103) is fixedly installed on a handle (101). A cable (102) is arranged inside the handle (101). One end of the cable (102) is electrically conductive with the plug (104). An unlocking button (106) is slidably embedded and installed on the circumferential surface of the mechanism box (103) along its radial direction, and the unlocking button (106) is in transmission cooperation with the snap movable plate (120); A second heating sheet (129) and a first heating sheet (115) are respectively embedded in the snap movable plate (120) and the unlocking button (106). A first force-sensitive resistor is arranged on the surface of the unlocking button (106) located outside the mechanism box (103) for measuring the pressing force of the unlocking button (106). When the user presses the unlocking button (106), the resistance value of the first force-sensitive resistor on the unlocking button (106) will decrease. A thermistor is also embedded in the unlocking button (106) or the snap movable plate (120); It also includes a 3V DC power supply, a 5V DC power supply, and a 12V DC power supply. A fixed resistor R3 and a second force-sensitive resistor (111) are serially arranged in the 3V DC power supply. A NPN triode is arranged in parallel at both ends of the second force-sensitive resistor (111). The base of the NPN triode is electrically connected to the positive end of the second force-sensitive resistor (111), and the emitter is electrically connected to the negative end of the second force-sensitive resistor (111). The collector and emitter of the NPN triode are serially connected in the 5V DC power supply. A fixed resistor R1, a first force-sensitive resistor, a fixed resistor R2, and a positive temperature coefficient thermistor are also serially arranged in the 5V DC power supply. Another NPN triode is arranged in parallel at both ends of the fixed resistor R2. The base of the NPN triode is electrically connected to the positive end of the fixed resistor R2, and the emitter is electrically connected to the negative end of the fixed resistor R2. The collector and emitter of the NPN triode are serially connected in the 12V DC power supply. A relay is also serially arranged in the 12V DC power supply. The open contacts of the relay are serially connected in the start-up circuit of the first heating sheet (115) and the second heating sheet (129) to control the on-off of the first heating sheet (115) and the second heating sheet (129).

2. The anti-freezing device for charging guns in alpine regions according to claim 1, characterized in that: The bottoms of the two snap slider rods (119) are fixedly connected to the end panel (107) through the snap slider rod bracket (118). A return spring (121) is wound around each snap slider rod (119). The two ends of the return spring (121) are fixedly connected to the snap movable plate (120) and the snap slider rod bracket (118).

3. The anti-freezing device for a charging gun in a high-cold region according to claim 2, wherein: Two symmetrically arranged swing frame brackets (122) are fixedly installed on the snap slider rod bracket (118). A swing frame (124) is movably connected between the two swing frame brackets (122). A roller (128) that is in contact and rolling fit with the snap movable plate (120) is rotatably installed at one end of the swing frame (124). A slide rail groove (127) is also formed on the swing frame (124). A sliding pin rod (126) is slidably installed in the slide rail groove (127).

4. The anti-freezing device for a charging gun in alpine regions according to claim 3, characterized in that: A guide slider rod bracket (123) is also fixedly installed on the snap slider rod bracket (118). Two parallel guide slider rods (116) are fixedly installed on the guide slider rod bracket (123). A toggle frame (117) is slidably installed on the two guide slider rods (116). The sliding pin rod (126) is fixedly installed on the toggle frame (117).

5. The anti-freezing device for a charging gun in alpine regions according to claim 4, characterized in that: Sliding sleeves (112) are slidably sleeved on the two guide slider rods (116). The bottoms of the two sliding sleeves (112) are fixedly fitted with the toggle frame (117). The tops of the two sliding sleeves (112) are fixedly fitted with the unlocking button (106). A limit lug (113) is fixedly installed on the unlocking button (106). The limit lug (113) is used to prevent the unlocking button (106) from separating from the mechanism box (103).

6. The anti-freezing device for charging gun in alpine regions according to claim 5, characterized in that: An auxiliary support plate (108) is fixedly installed in the inner wall of the mechanism box (103) in an overhead manner. The auxiliary support plate (108) is arranged parallel to the unlocking button (106). An auxiliary guiding slide rod (114) parallel to the axis of the sliding sleeve (112) is slidably installed on the auxiliary support plate (108). A spring (109) is wound around the auxiliary guiding slide rod (114). One end of the spring (109) is fixedly connected to the unlocking button (106), and the other end of the spring (109) is fixedly connected to a lower pressing plate (110). The auxiliary guiding slide rod (114) is fixedly matched with the unlocking button (106).

7. The anti-freezing device for charging gun in alpine regions according to claim 6, characterized in that: The lower pressing plate (110) is slidably sleeved on the outer surface of the auxiliary guiding slide rod (114). A second force-sensitive resistor (111) is arranged between the opposite surfaces of the lower pressing plate (110) and the auxiliary support plate (108). The second force-sensitive resistor (111) is used to detect the elastic force of the spring (109).

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