Marine active noise reduction fireproof multi-layer soundproof door

Abstract

The application belongs to the technical field of fireproof soundproof doors for ships, and discloses a ship active noise reduction fireproof multilayer soundproof door, which comprises a door frame, and a fireproof door is hingedly connected to one end of the door frame. The ANC active noise reduction module adopts active noise reduction technology, and the fireproof rock wool core can effectively separate the fire area from the non-fire area in the event of a fire, thereby ensuring personal safety. By manually pressing the fireproof lock to drive the tension disc to move downward, the sensor is started, the electric cylinder is driven to move downward, the inclined slot on the square plate drives the cylindrical slider to slide horizontally, when the square plate moves, the reverse translation of the gear rack is driven, at this time, the gear rack is clamped in the gear teeth, when the gear rotates, the telescopic baffle is driven to rotate in real time, thereby the L-shaped ball rod and the fireproof door can be tilted to achieve the effect of opening the door. The above-mentioned effect of automatically opening the door can be achieved by manually rotating and pressing the fireproof lock.

Description

Technical Field

[0001] This invention belongs to the technical field of marine fireproof and soundproof doors, specifically a marine active noise reduction fireproof multi-layer soundproof door. Background Technology

[0002] The main function of marine soundproof doors is to isolate and reduce noise, providing a quiet working environment for crew members. This is especially important in noisy areas such as ship engine rooms or machinery rooms, where noise not only affects the comfort of crew members but may also interfere with the normal operation of ship equipment. Given the long-term working environment of ships at sea, the doors used in cabins need to meet the ship's fire protection requirements while also having good sound insulation to ensure a good resting environment inside the cabins. The sound insulation of soundproof and fireproof doors is directly related to the thickness and density of the panels and rock wool. To achieve high-quality sound insulation, heavy door panels are required.

[0003] Currently, ship doors and panels are trending towards lightweight design. With the reduction in thickness and weight, the passive noise reduction of traditional soundproof and fireproof doors is difficult to meet the ever-increasing sound insulation requirements of ships. Even with the reduction in thickness and weight of fireproof and soundproof doors, the weight of ship-use fireproof and soundproof doors is still much greater than that of doors used in daily life. Therefore, it takes a certain amount of time and effort to open ship doors manually. If the door is opened in the event of a fire, it may result in personnel injury due to the door not being opened in time. Summary of the Invention

[0004] To address the problems mentioned in the background section, this invention provides a marine active noise reduction and fireproof multi-layer soundproof door.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a marine active noise reduction and fireproof multi-layer soundproof door, comprising a door frame, a fireproof door hinged to one end of the door frame, a fireproof lock fixedly connected to the outer wall of one end of the fireproof door, an ANC active noise reduction module fixedly connected to the inner wall of one end of the fireproof door, and a fireproof rock wool core fixedly connected to the other end of the fireproof door, wherein the ANC active noise reduction module and the fireproof rock wool core are fixedly connected, and further comprising:

[0006] The door auxiliary part includes a railing plate with an elastic tension structure. An arc groove is provided on the outer wall of one end of the door frame, and a lifting structure is provided in the arc groove. The lifting structure has an engaging rotation structure for driving the fire door to rotate and open at a fixed point.

[0007] Preferably, the elastic tension structure includes a spring and a tension plate fixedly connected to the bottom end of the spring. The bottom of the tension plate is fixedly connected to the fireproof lock. The tension plate is specifically divided into two parts: the part near the fireproof lock is made of a soft material, while the upper part is made of a hard material.

[0008] The elastic tension structure further includes a guardrail plate and a sensor fixedly connected to the inner wall of the bottom end of the guardrail plate. The sensor and the tension plate are fitted together, and the tension plate and the bottom end of the guardrail plate are slidably connected. The guardrail plate is also fixedly connected to the outer wall of one end of the fire door.

[0009] Preferably, the lifting structure includes an electric cylinder and a T-shaped sliding plate fixedly connected to the bottom end of the electric cylinder. A T-shaped groove plate is slidably engaged on the T-shaped sliding plate, and the T-shaped groove plate is fixedly connected to the inner wall of the arc groove.

[0010] Preferably, a square plate is fixedly connected to one end of the T-shaped slide plate, and an oblique groove is formed on the other end of the square plate. A U-shaped groove plate is fixedly connected to both outer walls of the T-shaped groove plate. A horizontal groove is formed through one end of the U-shaped groove plate, and a rectangular groove is formed on the inner walls of both the upper and lower surfaces of one end of the U-shaped groove plate.

[0011] Preferably, a U-shaped sliding plate is slidably connected to the inner wall of one end of the U-shaped groove plate, and a cylindrical slider is fixedly connected to the outer wall of one end of the U-shaped sliding plate.

[0012] Preferably, the cylindrical slider is slidably connected to the inclined groove and the horizontal groove, and rectangular sliders are fixedly connected to the outer walls of the upper and lower ends of the U-shaped slide plate, and the two rectangular sliders are slidably connected to the inner wall of the rectangular groove respectively.

[0013] Preferably, the meshing rotation structure includes a rack and a gear meshing with the rack. A telescopic guardrail is fixedly connected to the top of the gear. An L-shaped ball rod is movably sleeved on one side of the bottom of the telescopic guardrail, and the other end of the L-shaped ball rod is movably sleeved with a fire door.

[0014] A rod plate is fixedly connected to the inner wall of one side of the U-shaped slide plate. A rotating rack is rotatably connected to the rod plate. A second spring is fixedly connected to the outer wall of one end of the rotating rack. The other end of the second spring is fixedly connected to the inner wall of the other side of the U-shaped slide plate.

[0015] Preferably, a support rod is movably sleeved on the bottom end of the gear, and the bottom end of the support rod is fixedly connected to the inner wall of the arc groove. An arc plate is fixedly connected to the support rod.

[0016] Preferably, a circular groove plate is fixedly connected to one side of the top end of the arc plate, a spring three is fixedly connected to the inner wall of the bottom end of the circular groove plate, and a locking rod is fixedly connected to the top end of the spring three.

[0017] Preferably, the clamping rod and the inner wall of the circular groove plate are in close sliding connection, and the top of the clamping rod is slidably engaged with the gear.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] This invention utilizes active noise reduction technology through the ANC active noise reduction module, and together with the fireproof rock wool core installed inside the fire door, the two can effectively separate the fire and non-fire areas in the event of a fire, thus ensuring personal safety.

[0020] This invention allows for automatic door opening by manually pressing the fireproof lock on the fireproof door. The lock's rotation causes a pull plate to move downwards, contacting a sensor. This sensor then activates an electric cylinder, causing the diagonal groove on the square plate to move the cylindrical slider horizontally within the transverse groove. As the square plate moves upwards, it causes a rotating rack to move in the opposite direction, engaging with the teeth of a gear until it reaches the end of the rectangular groove. The rotating gear then rotates, causing the telescopic barrier to rotate, which in turn pulls the L-shaped lever and tilts the fireproof door, opening it. This automatic door opening is achieved simply by manually rotating and pressing the fireproof lock, avoiding the need for excessive manual force. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the fire door of the present invention when it is opened and its overall three-dimensional structure.

[0022] Figure 2 This is a schematic diagram of the fire door's closed and overall planar structure according to the present invention;

[0023] Figure 3 This is a top view of the overall cross-sectional structure of the fire door of the present invention;

[0024] Figure 4 This is a partial structural diagram of the auxiliary part of the door body of the present invention (one of the diagrams);

[0025] Figure 5 This is a partial structural diagram of the auxiliary part of the door body of the present invention;

[0026] Figure 6 This is a schematic diagram of a partially disassembled structure of the auxiliary part of the door body of the present invention (second part);

[0027] Figure 7 For the present invention Figure 6 A magnified view of the structure at point A in the middle;

[0028] Figure 8 For the present invention Figure 6 A magnified schematic diagram of the structure at point B in the middle.

[0029] In the picture:

[0030] 1. Door frame; 11. Fire door; 12. Fireproof lock; 13. ANC active noise reduction module; 14. Fireproof rock wool core;

[0031] 2. Gate auxiliary parts; 21. Guardrail plate; 22. Sensor; 23. Spring 1; 24. Tension plate; 25. Electric cylinder; 26. T-shaped groove plate; 27. T-shaped sliding plate; 28. Square plate; 29. ​​Diagonal groove; 230. U-shaped groove plate; 231. Horizontal groove; 232. Rectangular groove; 233. U-shaped sliding plate; 234. Cylindrical slider; 235. Rectangular slider; 236. Rod plate; 237. Rotary rack; 238. Spring 2; 239. Support rod; 240. Gear; 241. Arc plate; 242. Circular groove plate; 243. Spring 3; 244. Locking rod; 245. Telescopic guardrail plate; 246. L-shaped ball rod. Detailed Implementation

[0032] 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, and 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.

[0033] like Figures 1 to 8 As shown, this invention provides a marine active noise reduction and fireproof multi-layer soundproof door, including a door frame 1, a fireproof door 11 hinged to one end of the door frame 1, a fireproof lock 12 fixedly connected to the outer wall of one end of the fireproof door 11, an ANC active noise reduction module 13 fixedly connected to the inner wall of one end of the fireproof door 11, and a fireproof rock wool core 14 fixedly connected to the other end of the fireproof door 11. The ANC active noise reduction module 13 and the fireproof rock wool core 14 are fixedly connected. The invention also includes:

[0034] The door auxiliary part 2 includes a railing plate 21, which is provided with an elastic tension structure. An arc groove is provided on the outer wall of one end of the door frame 1, and a lifting structure is provided in the arc groove. The lifting structure is provided with an engaging rotation structure, which is used to drive the fire door 11 to rotate and open at a fixed point.

[0035] The above solution employs active noise reduction technology through the ANC active noise reduction module 13, and the fireproof rock wool core 14 installed inside the fire door 11 can effectively separate the fire and non-fire areas in the event of a fire, ensuring personal safety.

[0036] When the fireproof lock 12 on the fireproof door 11 is pressed manually, the rotation of the fireproof lock 12 will cause the pull plate 24 to move downward, causing the pull plate 24 to contact the sensor 22 downward, thereby activating the sensor 22 to drive the electric cylinder 25 to move downward. As a result, the inclined groove 29 on the square plate 28 will drive the cylindrical slider 234 to slide horizontally in the horizontal groove 231. When the square plate 28 moves upward, it will drive the rotating rack 237 to move in the opposite direction. At this time, the rotating rack 237 will be engaged in the teeth of the gear 240 until it moves to the end of the rectangular groove 232. When the gear 240 rotates, it will drive the telescopic barrier 245 to rotate in real time, thereby pulling the L-shaped ball rod 246 and tilting the fireproof door 11 to achieve the effect of opening the door. The above can achieve the effect of automatic door opening by simply rotating and pressing the fireproof lock 12, avoiding the need for excessive manual force to open the fireproof door 11.

[0037] The first point that needs to be added is that after the electric cylinder 25 is started, it continuously performs a reciprocating motion of lifting and lowering until the fire door 11 is opened to a specific position and angle. This technology is all existing technology that is programmed by computer.

[0038] The second point that needs to be added is that when the fire door 11 is manually closed, the gear 240 will rotate in the opposite direction. During the rotation, it will continuously slide and contact the rack 237, but there will be no jamming due to the presence of the rack 237. This is because the end of the gear 240 that actively contacts the rack 237 during the reverse rotation is an arc surface. Furthermore, with the setting and installation of the spring 238, even after the gear 240 is freely reversed, the rack 237 will still be driven by the spring 238 to mesh with the teeth of the gear 240.

[0039] The elastic tension structure includes a spring 23 and a tension plate 24 fixedly connected to the bottom of the spring 23. The bottom of the tension plate 24 is fixedly connected to the fireproof lock 12. The tension plate 24 is divided into two parts: the part near the fireproof lock 12 is made of soft material, while the upper part is made of hard material.

[0040] The elastic tension structure also includes a guardrail plate 21 and a sensor 22 fixedly connected to the inner wall of the bottom end of the guardrail plate 21. The sensor 22 and the tension plate 24 are closely connected, and the tension plate 24 and the bottom end of the guardrail plate 21 are slidably connected. The guardrail plate 21 is also fixedly connected to the outer wall of one end of the fire door 11.

[0041] Using the above scheme: drive the fireproof lock 12 to rotate and tilt. When the fireproof lock 12 rotates, it will drive the tension plate 24 to move downward, thereby pulling the spring 23 to deform, until the tension plate 24 moves downward to contact the sensor 22.

[0042] The lifting structure includes an electric cylinder 25 and a T-shaped sliding plate 27 fixedly connected to the bottom end of the electric cylinder 25. A T-shaped groove plate 26 is slidably engaged on the T-shaped sliding plate 27, and the T-shaped groove plate 26 is fixedly connected to the inner wall of the arc groove. A square plate 28 is fixedly connected to one end of the T-shaped sliding plate 27, and a diagonal groove 29 is formed on the other end of the square plate 28. U-shaped groove plates 230 are fixedly connected to the outer walls of both ends of the T-shaped groove plate 26. A horizontal groove 231 is formed through one end of the U-shaped groove plate 230. A rectangular groove 232 is provided in the inner wall of both the upper and lower sides of one end of the U-shaped groove plate 230. A U-shaped sliding plate 233 is slidably connected in the inner wall of one end of the U-shaped groove plate 230. A cylindrical slider 234 is fixedly connected to the outer wall of one end of the U-shaped sliding plate 233. The cylindrical slider 234 is in contact with the inclined groove 29 and the horizontal groove 231. A rectangular slider 235 is fixedly connected to the outer walls of both the upper and lower ends of the U-shaped sliding plate 233. Both rectangular sliders 235 are in contact with the inner wall of the rectangular groove 232 respectively.

[0043] Using the above scheme: sensor 22 drives electric cylinder 25 to move downward, thereby driving T-shaped slide plate 27 in T-shaped groove plate 26 to move downward synchronously. The downward moving T-shaped slide plate 27 will drive square plate 28 to move downward. As a result, the inclined groove 29 on square plate 28 will drive cylindrical slider 234 to slide horizontally in transverse groove 231. The cylindrical slider 234 will drive U-shaped slide plate 233 to slide in U-shaped groove plate 230. U-shaped groove plate 230 will be horizontally guided by the sliding of rectangular sliders 235 at the upper and lower ends in rectangular groove 232.

[0044] The meshing and rotating structure includes a rack 237 and a gear 240 that meshes with the rack 237. A telescopic guardrail 245 is fixedly connected to the top of the gear 240. An L-shaped ball rod 246 is movably sleeved on one side of the bottom end of the telescopic guardrail 245, and the other end of the L-shaped ball rod 246 is movably sleeved with the fire door 11.

[0045] A rod plate 236 is fixedly connected to the inner wall of one side of the U-shaped slide plate 233. A rotating rack 237 is rotatably connected to the rod plate 236. A spring 238 is fixedly connected to the outer wall of one end of the rotating rack 237. The other end of the spring 238 is fixedly connected to the inner wall of the other side of the U-shaped slide plate 233. A support rod 239 is movably sleeved on the bottom end of the gear 240. The bottom end of the support rod 239 is fixedly connected to the inner wall of the arc groove. An arc plate 241 is fixedly connected to the support rod 239. A circular groove plate 242 is fixedly connected to one side of the top end of the arc plate 241. A spring 243 is fixedly connected to the inner wall of the bottom end of the circular groove plate 242. A locking rod 244 is fixedly connected to the top end of the spring 243. The locking rod 244 is also in close contact with the inner wall of the circular groove plate 242. The top of the locking rod 244 is slidably engaged with the gear 240.

[0046] Using the above scheme: Conversely, when the square plate 28 moves upward, it will drive the rotating rack 237 to move in the opposite direction. At this time, the rotating rack 237 will be engaged in the teeth of the gear 240. The engagement process will maintain a specific angle to drive the gear 240 to rotate until it moves to the end of the rectangular groove 232. During the rotation of the gear 240, it will continuously press against the locking rod 244 on the circular groove plate 242. The locking rod 244 is retracted by the spring 243. When the gear 240 stops rotating, the locking rod 244 will be immediately engaged in the tooth spacing of the gear 240 by the drive of the spring 243, limiting the gear 240 and preventing the rotating rack 237 from moving in the forward direction while still driving the gear 240 to rotate. When the gear 240 rotates, it will drive the telescopic railing 245 to rotate in real time, thereby pulling the L-shaped ball rod 246 and the fire door 11 connected to the L-shaped ball rod 246 to tilt on the door frame 1, achieving the effect of opening the door.

[0047] The working principle and usage process of this invention: The active noise reduction module 13 adopts active noise reduction technology, and the fireproof rock wool core 14 installed inside the fire door 11 can effectively separate the fire and non-fire areas in the event of a fire, ensuring personal safety. The working state of the active noise reduction module 13 is that when a large amount of noise that is difficult to isolate occurs, it actively outputs the reverse sound volume to eliminate the impact of noise on the room and create a comfortable environment for the crew. Moreover, the fireproof rock wool core 14 will not be twisted or deformed when exposed to fire. It has the characteristics of being non-flammable, non-explosive, high temperature resistant, and corrosion resistant, which can effectively prevent the spread of flames and reduce the occurrence of fire accidents.

[0048] When the fire lock 12 on the fire door 11 is pressed manually, it rotates and tilts. This rotation causes the tension plate 24 to move downwards, pulling the spring 23 until it deforms. The tension plate 24 then contacts the sensor 22, activating the sensor and causing the electric cylinder 25 to move downwards. This causes the T-shaped slide plate 27 in the T-shaped groove 26 to move downwards simultaneously. The moving T-shaped slide plate 27 then moves the square plate 28 downwards. The inclined groove 29 on the square plate 28 causes the cylindrical slider 234 to slide horizontally within the transverse groove 231. The cylindrical slider 234 then causes the U-shaped slide plate 233 to slide within the U-shaped groove 230. The U-shaped groove 230 then moves downwards via the upper and lower sections... The rectangular slider 235 slides within the rectangular groove 232, thus guiding the horizontal movement. The movement of the U-shaped slide plate 233 drives the rack 237 on the rod plate 236 to move synchronously. The movement of the rack 237 is aided by the elasticity of the second spring 238, and it continuously slides and contacts the gear 240. Conversely, when the square plate 28 moves upward, it drives the rack 237 to move in the opposite direction. At this time, the rack 237 will engage with the teeth of the gear 240. The engagement process will maintain a specific angle to drive the gear 240 to rotate until it moves to the end of the rectangular groove 232. During the rotation of the gear 240, it will continuously press against the locking rod 244 on the circular groove plate 242. The locking rod 244 is retracted by the third spring 243.

[0049] When gear 240 stops rotating, lever 244, driven by spring 243, immediately engages with the tooth gap of gear 240, limiting gear 240 and preventing it from rotating when rack 237 moves forward. When gear 240 rotates, it drives telescopic barrier 245 to rotate, which in turn pulls L-shaped ball 246 and the fire door 11 connected to L-shaped ball 246 to tilt on door frame 1, achieving the opening effect. When fire door 11 is opened at an angle, telescopic barrier 245 will extend in real time, avoiding the potential problem of insufficient length causing insufficient opening angle of fire door 11. The above can achieve the effect of automatic door opening by manually rotating and pressing fire lock 12, avoiding the need for excessive manual force to open fire door 11.

[0050] The first point that needs to be added is that after the electric cylinder 25 is started, it continuously performs a reciprocating motion of lifting and lowering until the fire door 11 is opened to a specific position and angle. This technology is all existing technology that is programmed by computer.

[0051] The second point that needs to be added is that when the fire door 11 is manually closed, the gear 240 will rotate in the opposite direction. During the rotation, it will continuously slide and contact the rack 237, but there will be no jamming due to the presence of the rack 237. This is because the end of the gear 240 that actively contacts the rack 237 during the reverse rotation is an arc surface. Furthermore, with the setting and installation of the spring 238, even after the gear 240 is freely reversed, the rack 237 will still be driven by the spring 238 to mesh with the teeth of the gear 240.

[0052] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0053] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A marine active noise reduction fireproof multi-layer soundproof door, including a door frame (1), characterized in that: A fire door (11) is hinged to one end of the door frame (1), a fireproof lock (12) is fixedly connected to the outer wall of one end of the fire door (11), an ANC active noise reduction module (13) is fixedly connected to the inner wall of one end of the fire door (11), and a fireproof rock wool core (14) is fixedly connected to the other end of the fire door (11). The ANC active noise reduction module (13) and the fireproof rock wool core (14) are fixedly connected. The system also includes: The door auxiliary part (2) has an arc groove on the outer wall of one end of the door frame (1), and a lifting structure is provided in the arc groove. The lifting structure is provided with a meshing rotation structure, which is used to drive the fire door (11) to rotate and open at a fixed point. The elastic tension structure includes a spring (23) and a tension plate (24) fixedly connected to the bottom end of the spring (23). The bottom of the tension plate (24) is fixedly connected to the fireproof lock (12). The tension plate (24) is specifically divided into two parts: the part near the fireproof lock (12) is made of soft material, while the upper part is made of hard material. The elastic tension structure also includes a guardrail plate (21) and a sensor (22) fixedly connected to the inner wall of the bottom end of the guardrail plate (21). The sensor (22) and the tension plate (24) are fitted together, and the tension plate (24) and the bottom end of the guardrail plate (21) are slidably connected. The guardrail plate (21) is also fixedly connected to the outer wall of one end of the fire door (11). The lifting structure includes an electric cylinder (25) and a T-shaped sliding plate (27) fixedly connected to the bottom end of the electric cylinder (25). A T-shaped groove plate (26) is slidably engaged on the T-shaped sliding plate (27), and the T-shaped groove plate (26) is fixedly connected to the inner wall of the arc groove. A square plate (28) is fixedly connected to one end of the T-shaped sliding plate (27), and a diagonal groove (29) is provided on the other end of the square plate (28). A U-shaped groove plate (230) is fixedly connected to the outer walls of both ends of the T-shaped groove plate (26). A horizontal groove (231) is provided through one end of the U-shaped groove plate (230), and a rectangular groove (232) is also provided in the inner walls of the upper and lower surfaces of one end of the U-shaped groove plate (230). A U-shaped sliding plate (233) is slidably connected to the inner wall of one end of the U-shaped groove plate (230), and a cylindrical slider (234) is fixedly connected to the outer wall of one end of the U-shaped sliding plate (233). The cylindrical slider (234) is in close contact with the inclined groove (29) and the horizontal groove (231). The upper and lower outer walls of the U-shaped slide plate (233) are fixedly connected with rectangular sliders (235), and the two rectangular sliders (235) are in close contact with the inner wall of the rectangular groove (232). The meshing rotation structure includes a rack (237) and a gear (240) meshing with the rack (237). A telescopic guardrail (245) is fixedly connected to the top of the gear (240). An L-shaped ball rod (246) is movably sleeved on one side of the bottom end of the telescopic guardrail (245), and the other end of the L-shaped ball rod (246) is movably sleeved with the fire door (11). A rod plate (236) is fixedly connected to the inner wall of one side of the U-shaped slide plate (233). A rotating rack (237) is rotatably connected to the rod plate (236). A spring (238) is fixedly connected to the outer wall of one end of the rotating rack (237). The other end of the spring (238) is fixedly connected to the inner wall of the other side of the U-shaped slide plate (233). A support rod (239) is movably sleeved on the bottom end of the gear (240), and the bottom end of the support rod (239) is fixedly connected to the inner wall of the arc groove. An arc plate (241) is fixedly connected on the support rod (239). A circular groove plate (242) is fixedly connected to one side of the top of the arc plate (241), and a spring three (243) is fixedly connected to the inner wall of the bottom end of the circular groove plate (242), and a locking rod (244) is fixedly connected to the top of the spring three (243). The clamping rod (244) and the inner wall of the circular groove plate (242) are in close sliding connection, and the top of the clamping rod (244) is in sliding engagement with the gear (240); When the square plate (28) moves upward, it will drive the rack (237) to move in the opposite direction. At this time, the rack (237) will be engaged in the teeth of the gear (240) until it moves to the end of the rectangular slot (232). When the gear (240) stops rotating, the lever (244) will be driven by the spring (243) to immediately engage with the tooth gap of the gear (240) to limit the gear (240) and prevent the gear (240) from rotating when the rack (237) moves forward.

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