A plug-in sealing frame of a modular civil air defense door

Abstract

The application provides a modular civil air defense door plug-in sealing frame, and belongs to the technical field of civil air defense protection equipment. The civil air defense door plug-in sealing frame comprises a door frame, a main door which is slidably connected to the inner wall of the door frame, a hydraulic pump which is fixedly installed on the side wall of the door frame, a hydraulic rod which is fixedly installed on the hydraulic pump and fixedly connected to the side wall of the main door, a cleaning assembly which is located in the interior of the main door and is linked with the main door to clean the sliding rail, an oil spraying assembly which is located in the interior of the main door and is linked with the cleaning assembly to improve the lubricity of the sliding rail, and a baffle assembly which is located in the interior of the door frame and is linked with the main door to prevent foreign matters from falling into the sliding rail. The civil air defense door plug-in sealing frame has the beneficial effect that the above components are arranged to cover the groove when the door is opened to prevent foreign matters from falling into the sliding groove, clean the sliding groove and spray oil when the door is closed to increase the lubricating effect.

Description

Technical Field

[0001] This invention relates to the field of civil defense protection equipment technology, and more specifically, to a modular civil defense door with a plug-in sealing frame. Background Technology

[0002] Modular interlocking sealing frames for civil defense doors are the mainstream upgraded sealing structure for prefabricated civil defense equipment. They combine modular assembly technology with labyrinth interlocking sealing, taking into account both the convenience of industrial prefabrication construction and the core airtight performance of civil defense protection. They are gradually replacing traditional integral welded flat sealing door frames in newly built prefabricated underground garages, integrated pipe corridors, and subway civil defense projects. They are a standardized sealing system that takes into account both wartime explosion and poison protection and rapid installation and maintenance in peacetime.

[0003] Most modular air-raid shelter doors currently on the market have interlocking sealing frames where the slide rails or grooves are exposed or semi-exposed for extended periods. When the door is opened, these grooves are completely exposed to the external environment, easily accumulating dust, sand, construction debris, and other contaminants. This long-term accumulation significantly increases friction during sliding, exacerbates wear on the door frame and door body, shortens the lifespan of the sealing frame, and can also cause the door to jam. In emergency air-raid scenarios, such jamming can affect the normal opening and closing of the door, posing a safety hazard. Furthermore, most existing sealing frames lack self-cleaning and self-lubricating functions, requiring regular manual cleaning and lubrication of the slide rails. However, the slide rails are usually concealed, making manual maintenance difficult, inefficient, and unreliable. Therefore, inventing an interlocking sealing frame for modular air-raid shelter doors to address these issues has become a pressing problem for those skilled in the art. Summary of the Invention

[0004] To overcome the above shortcomings, this invention provides a modular interlocking sealing frame for air defense doors, which aims to solve the problems of debris easily falling into the slide groove when the door is opened and the lack of self-cleaning and self-lubricating functions in the equipment.

[0005] This invention is implemented as follows: This invention provides a modular air-raid shelter door with a plug-in sealing frame, including a door frame, a main door slidably connected to the inner wall of the door frame, a hydraulic pump fixedly installed on the side wall of the door frame, a hydraulic rod fixedly installed on the hydraulic pump, and the hydraulic rod fixedly connected to the side wall of the main door, and further comprising: A cleaning component is located inside the main door and works in conjunction with the main door to clean the slide rails. An oil spraying assembly is located inside the main door. The oil spraying assembly works in conjunction with a cleaning assembly to improve the lubrication of the slide rails. A baffle assembly is located inside the door frame and works in conjunction with the main door to prevent external debris from falling into the slide rail.

[0006] Preferably, the cleaning assembly includes a straight shaft, which is rotatably connected to the inner wall of the main door. A cleaning plate is fixedly installed at one end of the straight shaft, and the cleaning plate is located below the main door. A rotating rod and a spur gear are fixedly installed on the outer wall of the straight shaft, and the spur gear is meshed with a rack. The rack is fixedly connected to the side wall of the door frame, and a filter plate is fixedly installed on the inner wall of the main door.

[0007] Preferably, a base plate is fixedly installed on the outer wall of the filter plate, the base plate is rotatably connected to a straight shaft, an internal gear is fixedly installed at the end of the straight shaft away from the spur gear, the internal gear meshes with a planetary gear, the planetary gear is rotatably connected to the side wall of the base plate, the planetary gear meshes with an external gear, a fan blade is fixedly installed on the outer wall of the external gear, and an air hole is opened on the inner wall of the main door, the air hole is located above the fan blade.

[0008] Preferably, the fuel injection assembly includes a liquid storage tank, which is fixedly connected to the inner wall of the main door. A liquid outlet pipe and a piston pipe are fixedly installed on the inner wall of the liquid storage tank, and a piston rod is slidably connected to the inner wall of the piston pipe.

[0009] Preferably, a sliding plate is fixedly installed at one end of the piston rod, a first spring is sleeved on the outer wall of the piston tube, the two ends of the first spring are fixedly connected to the outer wall of the liquid storage tank and the side wall of the sliding plate, respectively, the sliding plate is slidably connected to the inner wall of the main door, and the sliding plate is located on the same side of the rotating rod.

[0010] Preferably, the baffle assembly includes an inner side plate, which is slidably connected to the inner wall of the door frame. A support rod is slidably connected to the inner wall of the inner side plate and fixedly connected to the inner wall of the door frame. A second spring is sleeved on the outer wall of the support rod, and the two ends of the second spring are fixedly connected to the outer wall of the inner side plate and the inner wall of the door frame, respectively. An outer side plate is slidably connected to the inner wall of the inner side plate and fixedly connected to the side wall of the main door.

[0011] The beneficial effects of this invention are: This equipment uses a hydraulic pump to control the extension and retraction of a hydraulic rod, which drives the main door to slide back and forth in a straight line along the inner wall of the door frame. The rack installed on the door frame drives the spur gear on the main door to rotate, causing the straight shaft to rotate, which in turn drives the internal gear, planetary gear, and external gear. The fan blades fixed on the outer wall of the external gear rotate at high speed, generating a directional high-pressure airflow. This airflow is then directed through the front air hole and sprayed onto the surface of the slide rail to be cleaned, continuously blowing fine dust, sand, and other light debris forward, achieving pneumatic pre-cleaning of the slide rail. At the same time, the straight shaft drives the cleaning plate to rotate, causing the cleaning plate to rotate synchronously while moving axially along the slide rail with the main door, physically scraping away stubborn impurities such as sludge, rust particles, and hard debris attached to the bottom and side walls of the slide rail.

[0012] During the above process, the rotating rod rotates synchronously with the straight shaft, and its end slides along the end face of the sliding plate and applies axial thrust, thereby pushing the sliding plate along the guide groove of the inner wall of the main door towards the liquid storage tank. Under pressure, the pre-stored lubricating oil is squeezed out at a constant speed through the liquid outlet pipe and guided to the surface of the slide rail, completing a quantitative oil supply. At the same time, the inner side plate and the outer side plate are slidably connected, so that the two inner side plates squeeze the second spring on both sides, causing them to be compressed. The originally spliced ​​and closed inner side plates then separate on both sides along the inner wall of the door frame, smoothly making way for the sliding passage of the main door without obstructing the normal movement of the main door. This effectively improves the sealing performance of the track area and prevents dust and debris from falling into the slide rail. Attached Figure Description

[0013] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the main view structure of the interlocking sealing frame of a modular air defense door provided by an embodiment of the present invention; Figure 2 This is a side view structural diagram of the interlocking sealing frame of a modular air defense door provided by an embodiment of the present invention; Figure 3 This is a schematic diagram of the main door structure of a modular air defense door with a plug-in sealing frame, provided by an embodiment of the present invention. Figure 4 This is a top-view structural diagram of a modular air defense door with a plug-in sealing frame, provided by an embodiment of the present invention. Figure 5 This is a partial schematic diagram of the interlocking sealing frame structure of a modular air defense door provided by an embodiment of the present invention; Figure 6 This is a partial cross-sectional schematic diagram of the main door structure of the interlocking sealing frame of a modular air defense door provided by an embodiment of the present invention; Figure 7 This is a schematic diagram of the interlocking sealing frame cleaning assembly structure of a modular air defense door provided by an embodiment of the present invention; Figure 8 This is a cross-sectional schematic diagram of the interlocking sealing frame cleaning assembly structure of a modular air defense door provided by an embodiment of the present invention; Figure 9 This is a cross-sectional schematic diagram of the oil spraying assembly structure of the interlocking sealing frame of a modular air defense door provided by an embodiment of the present invention; Figure 10 This invention provides a modular air defense door with a plug-in sealing frame. Figure 2 An enlarged schematic diagram of structure A; Figure 11 This invention provides a modular air defense door with a plug-in sealing frame. Figure 6 An enlarged schematic diagram of B in the structure; Figure 12 This is a top-view structural diagram of a plug-in sealing frame cleaning assembly for a modular air defense door provided by an embodiment of the present invention.

[0015] In the diagram: 1. Door frame; 2. Main door; 3. Hydraulic pump; 4. Hydraulic rod; 5. Cleaning assembly; 501. Cleaning plate; 502. Straight shaft; 503. Rotating rod; 504. Spur gear; 505. Filter plate; 506. Rack; 507. Base plate; 508. Internal gear; 509. Planetary gear; 510. External gear; 511. Fan blade; 512. Air hole; 6. Oil injection assembly; 601. Liquid storage tank; 602. Liquid outlet pipe; 603. Piston pipe; 604. Piston rod; 605. First spring; 606. Slide plate; 7. Baffle assembly; 701. Inner side plate; 702. Support rod; 703. Second spring; 704. Outer side plate. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] Example, refer to Figures 1-11A modular air-raid shelter door with a plug-in sealing frame includes a door frame 1, a main door 2 slidably connected to the inner wall of the door frame 1, a hydraulic pump 3 fixedly installed on the side wall of the door frame 1, a hydraulic rod 4 fixedly installed on the hydraulic pump 3, and the hydraulic rod 4 fixedly connected to the side wall of the main door 2. The door also includes: Cleaning component 5 is located inside the main door 2. Cleaning component 5 works in conjunction with the main door 2 to clean the slide rails. The oil spraying assembly 6 is located inside the main door 2. The oil spraying assembly 6 works in conjunction with the cleaning assembly 5 to improve the lubrication of the slide rail. Baffle assembly 7 is located inside the door frame 1. Baffle assembly 7 works in conjunction with the main door 2 to prevent external debris from falling into the slide rail.

[0018] Furthermore, the cleaning assembly 5 includes a straight shaft 502, which is rotatably connected to the inner wall of the main door 2. A cleaning plate 501 is fixedly installed at one end of the straight shaft 502, and the cleaning plate 501 is located below the main door 2. A rotating rod 503 and a spur gear 504 are fixedly installed on the outer wall of the straight shaft 502, respectively. The spur gear 504 is meshed with a rack 506, which is fixedly connected to the side wall of the door frame 1. A filter plate 505 is fixedly installed on the inner wall of the main door 2, and a filter plate 505 is fixedly installed on the outer wall of the filter plate 505. There is a base plate 507, which is rotatably connected to a straight shaft 502. An internal gear 508 is fixedly installed at the end of the straight shaft 502 away from the spur gear 504. The internal gear 508 is meshed with a planetary gear 509. The planetary gear 509 is rotatably connected to the side wall of the base plate 507. The planetary gear 509 is meshed with an external gear 510. A fan blade 511 is fixedly installed on the outer wall of the external gear 510. An air hole 512 is opened on the inner wall of the main door 2. The air hole 512 is located above the fan blade 511.

[0019] It should be noted that when the main door 2 transitions from the fully open state to the closed state, the electronic control system issues a control command to start the hydraulic pump 3. Pressurized oil enters the hydraulic cylinder through the oil circuit, pushing the hydraulic rod 4 to contract at a uniform speed. Under the traction of the hydraulic rod 4, the main door 2 slides smoothly along the pre-set groove on the inner wall of the door frame 1. The spur gear 504 and rack 506 maintain close meshing at all times. While the spur gear 504 moves linearly with the main door 2, it also achieves synchronous rotation, converting the translational kinetic energy of the door leaf into rotational power, which is transmitted to the cleaning assembly 5 through the straight shaft 502. The internal gear 508 rotates synchronously with the straight shaft 502 at a low speed. The meshing of the tooth surfaces drives several planetary gears 509 to revolve around the central axis and rotate on their own axis. After completing the speed increase and torque reduction, the planetary gears 509 drive the central external gear 510 to operate stably at a speed several times that of the straight shaft 502. The fan blades 511 fixed on the outer wall of the external gear 510 rotate at high speed to generate directional airflow. The airflow is transported along the preset flow channel inside the main door 2 to the end near the middle vertical mullion. It is then directionally sprayed through the air hole 512 near the middle vertical mullion to the surface of the slide rail to be cleaned. This continuously transports the fine dust, sand and other light debris in the slide rail to the end near the middle vertical mullion until they flow into the dust collection groove below the vertical mullion in the door frame 1, so as to facilitate the pneumatic pre-cleaning of the slide rail.

[0020] Meanwhile, a cleaning plate 501 (which can be made of wear-resistant rubber but is not limited to) is fixed at the end of the straight shaft 502 near the slide rail. When the straight shaft 502 rotates, it drives the cleaning plate 501 to rotate synchronously. The cleaning plate 501 moves axially along the slide rail together with the main door 2, forming a compound motion of rotating brush and axial propulsion. This physically scrapes away stubborn impurities such as sludge, rust particles, and hard debris attached to the bottom and side walls of the slide rail. The removed impurities move forward along the slide rail under the pushing action of the cleaning plate 501 and eventually collect together with the debris blown by the pneumatic system in the collection groove below the vertical rod in the door frame 1, thus completing the deep cleaning of the entire slide rail.

[0021] Once the main door 2 is fully opened, the cleaning component 5 has cleaned and collected all the impurities in the entire slide rail into the collection trough below the central mullion. Staff only need to periodically open the sealing cover at the central mullion of the door frame 1 to centrally remove the debris from the collection trough. Daily maintenance is simple and requires little work.

[0022] Reference Figures 3-11Furthermore, the fuel injection assembly 6 includes a liquid storage tank 601, which is fixedly connected to the inner wall of the main door 2. A liquid outlet pipe 602 and a piston pipe 603 are fixedly installed on the inner wall of the liquid storage tank 601. A piston rod 604 is slidably connected to the inner wall of the piston pipe 603. The piston rod 604 is characterized in that a sliding plate 606 is fixedly installed at one end of the piston rod 604. A first spring 605 is sleeved on the outer wall of the piston pipe 603. The two ends of the first spring 605 are fixedly connected to the outer wall of the liquid storage tank 601 and the side wall of the sliding plate 606, respectively. The sliding plate 606 is slidably connected to the inner wall of the main door 2 and is located on the same side of the rotating rod 503.

[0023] It should be noted that: simultaneously, the rotating rod 503 rotates synchronously with the straight shaft 502. When the free end of the rotating rod 503 rotates to the position of contacting the sliding plate 606, as the rotating rod 503 continues to rotate, its end slides along the end face of the sliding plate 606 and applies axial thrust, pushing the sliding plate 606 smoothly along the guide groove on the inner wall of the main door 2 towards the liquid storage tank 601. During the sliding process, the sliding plate 606 drives the piston rod 604, which is fixed to it, to advance into the liquid storage tank 601 along the piston tube 603, compressing the internal oil storage space of the liquid storage tank 601, so that the pre-stored lubricating oil in the tank can be stored in the liquid storage tank. Under pressure, the fluid is extruded at a constant speed through the outlet pipe 602 and guided to the slide rail surface, completing one quantitative lubrication operation. When the rotating rod 503 continues to rotate until it disengages from the sliding plate 606, the sliding plate 606 and the piston rod 604 lose axial thrust and move in the opposite direction along the piston tube 603 under the elastic restoring force of the first spring 605, restoring the internal volume of the storage tank 601 and preparing for the next oil supply (an oil inlet check valve is installed at the oil inlet of the storage tank 601 and the piston tube 603, and an oil outlet check valve is installed at the inlet of the outlet pipe 602).

[0024] As the straight shaft 502 continues to rotate, since the two ends of the sliding plate 606 and the rotating rod 503 are the same, allowing for both forward and reverse rotation, the above oil supply process is repeated to achieve segmented and uniform lubrication of the slide rail. This avoids the waste and oil accumulation caused by a large amount of lubricating oil overflowing at once, and ensures that a continuous and uniform oil film is formed on the entire slide rail surface. This effectively reduces the frictional resistance during the opening and closing of the main door 2, slows down the wear rate of the track and rollers, and also isolates the main door 2 from the moisture and corrosive media in the underground humid environment. This prevents the main door 2 from jamming or failing to close completely due to slide rail corrosion and increased friction after long-term use, and effectively ensures that the air defense door can reliably and smoothly complete the opening and closing operation in an emergency.

[0025] When the main door 2 changes from the closed state to the open state, the electronic control system controls the hydraulic pump 3 to run in reverse, driving the hydraulic rod 4 to extend at a constant speed, pushing the main door 2 to slide smoothly to both sides along the inner wall groove of the door frame 1. The spur gear 504 fixed on the side of the main door 2 rotates and meshes in the opposite direction along the rack 506. The cleaning plate 501 at the end of the straight shaft 502 rotates in the opposite direction with the straight shaft 502 and moves in the opposite direction along the slide rail with the main door 2, forming a compound motion of rotating brush and axial propulsion. The lubricating oil on the surface of the slide rail is evenly scraped to each corner of the slide rail, filling the areas where the oil film is too thin or lacks oil, ensuring that a lubricating oil film of uniform thickness, continuous integrity and full coverage is formed on the entire slide rail surface.

[0026] Reference Figures 4-11 Furthermore, the baffle assembly 7 includes an inner side plate 701, which is slidably connected to the inner wall of the door frame 1. A support rod 702 is slidably connected to the inner wall of the inner side plate 701, and the support rod 702 is fixedly connected to the inner wall of the door frame 1. A second spring 703 is sleeved on the outer wall of the support rod 702, and the two ends of the second spring 703 are fixedly connected to the outer wall of the inner side plate 701 and the inner wall of the door frame 1, respectively. An outer side plate 704 is slidably connected to the inner wall of the inner side plate 701, and the outer side plate 704 is fixedly connected to the side wall of the main door 2.

[0027] It should be noted that when the main door 2 moves in the closing direction, the outer side plate 704 fixed to the side wall of the main door 2 moves synchronously with the main door 2. At this time, the two inner side plates 701 are in a merged state. However, since the ends of the inner side plates 701 and the front ends of the outer side plates 704 are also in an arc shape, and the ends of the inner side plates 701 and the front ends of the outer side plates 704 are simultaneously in a sliding connection, the outer side plate 704 slides along the inner wall of the inner side plates 701. As the outer side plates 704 continue to advance, the two inner side plates 701 press the second springs 703 to both sides. The second springs 703 are compressed, causing the originally spliced ​​and closed inner side plates 701 to separate to both sides along the inner wall of the door frame 1, smoothly making way for the passage of the sliding main door 2. This will not obstruct the normal movement of the main door 2. Furthermore, under the action of the second springs 703, the outer side plates 704 and the inner side plates 701 are in a taut state, thereby increasing the sealing performance.

[0028] When the main door 2 is fully opened, the slide rail section that was originally exposed will be completely exposed after the main door 2 moves. At this time, the two inner side plates 701 that are no longer squeezed by the outer side plate 704 will slide along the inner wall of the door frame 1 towards the middle and re-join and close under the elastic restoring force of the second spring 703, completely covering the exposed slide rail opening. When the main door 2 moves to the closing direction, the slide rail section behind the main door 2 that has been cleaned and lubricated will also be quickly closed by the inner side plate 701 at the corresponding position after the main door 2 leaves, under the push of the second spring 703, to cover the slide rail opening.

[0029] When the main door 2 is fully open, the baffle assembly 7 completely covers the sliding rail openings not covered by the main door 2. When the main door 2 is fully closed, the sliding rail openings are completely covered by the main door 2, thereby preventing sand, dust, water and other debris from falling into the sliding rail during underground construction or daily use. This reduces the accumulation of impurities inside the sliding rail from the source, reduces the workload of the cleaning assembly 5, and further ensures that the air-raid shelter door maintains smooth opening and closing during long-term use. It will not cause problems such as jamming or poor sealing due to the accumulation of impurities or corrosion of the sliding rail. This effectively improves the working reliability and service life of the modular air-raid shelter door's plug-in sealing frame, and can better meet the protection requirements of air-raid shelter projects in emergency situations.

[0030] It should be noted that the specific model and specifications need to be selected and determined based on the actual specifications of the device. The specific selection and calculation method adopts the existing technology in this field, so it will not be described in detail here.

[0031] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A modular air-raid shelter door with a plug-in sealing frame, comprising a door frame (1), a main door (2) slidably connected to the inner wall of the door frame (1), a hydraulic pump (3) fixedly installed on the side wall of the door frame (1), a hydraulic rod (4) fixedly installed on the hydraulic pump (3), and the hydraulic rod (4) fixedly connected to the side wall of the main door (2), characterized in that, Also includes: Cleaning component (5), the cleaning component (5) is located inside the main door (2), the cleaning component (5) is linked with the main door (2) to clean the slide rail; The oil spraying assembly (6) is located inside the main door (2). The oil spraying assembly (6) works in conjunction with the cleaning assembly (5) to improve the lubrication of the slide rail. Baffle assembly (7) is located inside the door frame (1) and cooperates with the main door (2) to prevent external debris from falling into the slide rail.

2. The interlocking sealing frame of a modular air-raid shelter door according to claim 1, characterized in that, The cleaning assembly (5) includes a straight shaft (502), which is rotatably connected to the inner wall of the main door (2). A cleaning plate (501) is fixedly installed at one end of the straight shaft (502), and the cleaning plate (501) is located below the main door (2). A rotating rod (503) and a spur gear (504) are fixedly installed on the outer wall of the straight shaft (502). The spur gear (504) is meshed with a rack (506), and the rack (506) is fixedly connected to the side wall of the door frame (1). A filter plate (505) is fixedly installed on the inner wall of the main door (2).

3. The interlocking sealing frame of a modular air-raid shelter door according to claim 2, characterized in that, A base plate (507) is fixedly installed on the outer wall of the filter plate (505). The base plate (507) is rotatably connected to the straight shaft (502). An internal gear (508) is fixedly installed at the end of the straight shaft (502) away from the spur gear (504). The internal gear (508) is meshed with a planetary gear (509). The planetary gear (509) is rotatably connected to the side wall of the base plate (507). The planetary gear (509) is meshed with an external gear (510). A fan blade (511) is fixedly installed on the outer wall of the external gear (510). An air hole (512) is opened on the inner wall of the main door (2). The air hole (512) is located above the fan blade (511).

4. The interlocking sealing frame of a modular air-raid shelter door according to claim 3, characterized in that, The fuel injection assembly (6) includes a liquid storage tank (601), which is fixedly connected to the inner wall of the main door (2). The inner wall of the liquid storage tank (601) is fixedly installed with a liquid outlet pipe (602) and a piston pipe (603), and the inner wall of the piston pipe (603) is slidably connected with a piston rod (604).

5. The interlocking sealing frame of a modular air-raid shelter door according to claim 4, characterized in that, A sliding plate (606) is fixedly installed at one end of the piston rod (604). A first spring (605) is sleeved on the outer wall of the piston tube (603). The two ends of the first spring (605) are fixedly connected to the outer wall of the liquid storage tank (601) and the side wall of the sliding plate (606), respectively. The sliding plate (606) is slidably connected to the inner wall of the main door (2). The sliding plate (606) is located on the same side of the rotating rod (503).

6. The interlocking sealing frame of a modular air-raid shelter door according to claim 1, characterized in that, The baffle assembly (7) includes an inner side plate (701), which is slidably connected to the inner wall of the door frame (1). A support rod (702) is slidably connected to the inner wall of the inner side plate (701), and the support rod (702) is fixedly connected to the inner wall of the door frame (1). A second spring (703) is sleeved on the outer wall of the support rod (702). The two ends of the second spring (703) are fixedly connected to the outer wall of the inner side plate (701) and the inner wall of the door frame (1), respectively. An outer side plate (704) is slidably connected to the inner wall of the inner side plate (701), and the outer side plate (704) is fixedly connected to the side wall of the main door (2).

Images