Protective door for civil air defense engineering

Abstract

The utility model relates to the technical field of protective door, specifically relates to a protective door for civil air defence engineering, including door frame, rotation axis and the door leaf that can rotatably set on the door frame through rotation axis, the door sill subassembly of liftable is arranged on the door frame, sets up transmission mechanism between rotation axis and the door sill subassembly, and the automatic lifting of door sill is realized through pure mechanical linkage structure, and the difficult problem that traditional movable door sill needs manual installation, is inconvenient to keep and is easy to lose is solved completely, the core transmission disc subassembly and leaf spring design, can effectively absorb the overstroke in the last section of door leaf closing, the mechanism jamming phenomenon that may appear after door leaf block and door sill card slot locking is avoided ingeniously, ensure that the protective door can be smoothly opened under the emergency state, thereby, while improving civil air defence engineering emergency response speed and the degree of automation, the reliability and security of equipment are greatly enhanced.

Description

Technical Field

[0001] This utility model relates to the field of protective door technology, specifically a protective door for civil defense projects. Background Technology

[0002] In existing civil defense projects, protective doors often need to be equipped with threshold structures to ensure their airtightness and impact resistance. The traditional approach is to use independent "movable thresholds", which are manually installed into the pre-set slots at the bottom of the door frame before the battle.

[0003] This design has significant drawbacks: First, as an independent component, the movable threshold needs to be properly stored in peacetime, which not only occupies space but is also easily lost or damaged due to management negligence, making it impossible to quickly deploy in wartime and posing a serious safety hazard. Second, the installation and disassembly process relies entirely on manual operation, which is inefficient and cannot meet the requirements for rapid emergency response. In addition, to solve this problem, some existing technologies have developed automatic lifting threshold structures linked to the door leaf, but their transmission mechanisms are often quite rigid. After the door leaf is closed, the threshold rises to its highest point and locks with the door leaf, if there is a slight overtravel due to processing errors or installation deviations, the entire linkage mechanism can easily be in a dead position or unable to open in reverse due to rigidity, i.e., a "jamming" phenomenon, which is a fatal flaw in emergency situations.

[0004] Therefore, in view of the above situation, there is an urgent need to develop a protective door for civil defense projects to overcome the shortcomings in current practical applications and meet current needs. Utility Model Content

[0005] The purpose of this utility model is to provide a protective door for civil defense projects, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a protective door for civil defense projects, comprising a door frame, a rotating shaft, and a door leaf rotatably mounted on the door frame via the rotating shaft. The door frame is provided with a liftable threshold assembly, and a transmission mechanism is provided between the rotating shaft and the threshold assembly. When the door leaf is closed, the threshold assembly can be driven to rise via the rotating shaft and the transmission mechanism, thereby locking the door leaf and the raised threshold assembly together.

[0007] Specifically, by setting up a transmission mechanism linked to the rotating shaft to drive the threshold assembly to rise and fall, the threshold is automatically and synchronously raised and locked during the closing process. This design significantly improves the sealing performance and overall protective effectiveness of the security door. The precise cooperation between the transmission mechanism and the threshold assembly ensures that the threshold is driven to the highest position only when the door is nearly fully closed, and finally achieves reliable locking through the engagement of the locking block and the locking slot. The elastic buffer in the transmission plate assembly effectively absorbs overload force and prevents the mechanism from jamming due to processing or installation errors. This ensures both the smooth closing process and the reliability of self-locking, and also ensures that the door can be opened smoothly in an emergency, thereby comprehensively enhancing the automation, safety, and practical reliability of the civil defense project security door.

[0008] Preferably, the threshold assembly includes a threshold, a drive shaft, and a threaded pair; the threshold is vertically mounted on the bottom of the door frame; the drive shaft is rotatably mounted on the threshold, and its lower half is provided with a key; the threaded pair is fixed on the threshold and threadedly connected to the upper half of the drive shaft.

[0009] Specifically, by fixing the threaded pair to the sill and forming a helical transmission with the drive shaft, when the drive shaft is driven to rotate by the transmission mechanism, its own rotation can be efficiently and accurately converted into the linear lifting and lowering motion of the sill. The transmission is smooth and has a self-locking characteristic, ensuring the positional stability of the sill after it is raised. At the same time, the key structure set in the lower half of the drive shaft allows it to slide relative to the third bevel gear along the axial direction while transmitting torque, thereby seamlessly transmitting the rotational power to the vertically moving sill as a whole. This decouples the power transmission from the lifting and lowering of the components, making the entire sill assembly compact and reliable in linkage.

[0010] Preferably, the transmission mechanism includes a first bevel gear, a second bevel gear, a third bevel gear, and a transmission shaft assembly; the second bevel gear is fixed to the bottom end of the rotating shaft; the transmission shaft assembly is mounted on the door frame, with a first bevel gear at each end, wherein the first bevel gear at one end meshes with the second bevel gear; the third bevel gear is slidably sleeved on the lower half of the drive shaft and meshes with the first bevel gear at the other end, and the inner hole of the third bevel gear has a keyway adapted to the key of the drive shaft.

[0011] Specifically, by setting up a bevel gear transmission chain consisting of a first bevel gear, a second bevel gear, and a third bevel gear, and using a transmission shaft assembly for power transmission, the rotation of the vertical axis is cleverly converted into horizontal transmission, and finally back into the rotation of the drive shaft, achieving two efficient and reliable changes in the direction of power transmission. In particular, the sliding engagement between the keyway in the inner hole of the third bevel gear and the key on the drive shaft allows the rotational power to be continuously transmitted to the drive shaft without hindering the necessary axial movement of the drive shaft under the side effects of the thread. This perfectly decouples the rotational motion from the lifting motion, ensuring that the entire transmission process is smooth, precise, and structurally stable and reliable.

[0012] Preferably, the drive shaft assembly includes two coaxial drive shafts and a drive disc assembly connected between the two drive shafts; the two drive shafts are mounted on the door frame via bearing seats, and a first bevel gear is fixed to their outer ends respectively.

[0013] Specifically, by using two coaxial drive shafts connected by a transmission disc assembly to form a torque-transmitting unit, a long shaft is cleverly divided into two independently supported sections. This split structure effectively reduces the machining accuracy requirements of the bearing housing mounting surface on the door frame, simplifies the assembly process, and can adapt to minor deformations and installation errors, ensuring the flexibility and stability of the overall rotation of the drive shaft assembly. At the same time, this design provides structural space for integrating a transmission disc assembly with buffering and overload protection functions between the two drive shafts, making power transmission smoother and more reliable, and improving the adaptability of the entire transmission system to working conditions.

[0014] Preferably, the transmission disk assembly includes two transmission disks respectively fixed to the ends of two transmission shafts, and an elastic buffer disposed between the two transmission disks; one of the transmission disks is provided with a positioning shaft, and the other transmission disk is provided with a positioning groove that is clearance-fitted with the positioning shaft.

[0015] Specifically, by setting an elastic buffer between the two transmission discs and utilizing the clearance fit between the positioning shaft and the positioning groove, a flexible coupling mechanism with torque transmission, angle compensation, and overload protection functions is constructed. The elastic buffer can effectively absorb the impact energy at the end of the door closing and the overload force caused by manufacturing errors, preventing the mechanism from jamming. The fit between the positioning shaft and the positioning groove, while allowing a certain radial and angular offset, ensures the synchronization of torque transmission and the alignment between the two transmission discs, thereby significantly improving the adaptability and operational reliability of the transmission system under conditions with installation errors or slight deformation.

[0016] Preferably, the elastic buffer is a set of leaf springs, and baffles are fixed on the opposite surfaces of the two transmission discs, with the two ends of the leaf springs abutting against the baffles of the two transmission discs respectively.

[0017] Specifically, by employing multiple leaf springs as elastic buffers, with their ends respectively abutting against baffles fixed on two transmission discs, a highly efficient and reliable circumferential buffer mechanism is constructed. The leaf springs, with their high stiffness and fatigue resistance, provide precise and powerful elastic buffering at the end of the door's closing phase, effectively absorbing impact energy and allowing limited relative rotation between the transmission discs, thus preventing the mechanism from jamming. The baffle design not only provides a stable support plane for the leaf springs, ensuring uniform force transmission and avoiding stress concentration, but also enables the buffer structure to withstand frequent compression and release, greatly improving the durability of the transmission disc assembly and its long-term reliability under harsh working conditions.

[0018] Preferably, the threshold assembly further includes a guide mechanism for limiting the direction of threshold displacement. The guide mechanism includes a sliding shaft fixed on the threshold and a sliding sleeve fixed on the door frame and slidingly engaging with the sliding shaft.

[0019] Specifically, by setting up a guide mechanism consisting of a sliding shaft fixed to the threshold and a sliding sleeve fixed to the door frame, precise linear guidance and stable lateral support are provided for the lifting and lowering movement of the threshold. This effectively prevents the threshold from shifting, jamming, or shaking due to uneven force during the lifting and lowering process, ensuring the alignment accuracy and engagement reliability between the threshold and the locking block on the door leaf. This sliding friction pair structure is simple and reliable. It can not only effectively transfer and distribute the radial load borne by the drive shaft and threaded pair to the door frame, improving the stress state of the core transmission components, but also significantly improve the running stability and structural durability of the entire threshold assembly under frequent lifting and lowering movements.

[0020] Preferably, a slot is provided on the side of the threshold, and a corresponding block is fixed to the door leaf to match the slot. When the door leaf is fully closed and the threshold is raised to the highest position, the block is embedded in the slot.

[0021] Specifically, by creating a slot on the side of the threshold and setting a matching locking block at the corresponding position on the door leaf, a precise interlocking mechanical structure is formed the instant the door leaf is fully closed and the threshold is raised to its highest position. This design tightly integrates the door leaf and threshold from originally independent components into a robust whole, greatly enhancing the overall structural rigidity and impact resistance of the protective door when closed. This rigid locking mechanism effectively prevents displacement or vibration that may occur between the door leaf and threshold under external pressure or impact load, thereby significantly improving the airtightness and protection level of the civil defense project. At the same time, this mechanical interlocking structure is simple and reliable, and can achieve automatic locking and unlocking without additional operation.

[0022] Preferably, the door frame consists of an upper door frame beam, a lower door frame beam, a left side beam, and a right side beam. The beams and side beams are connected by connecting ears and connecting slots and fixed with bolts.

[0023] Specifically, by designing the door frame as a modular, split structure consisting of an upper door frame beam, a lower door frame beam, and left and right side beams, and using connecting ears and connecting slots for interlocking and bolting at the connection points between the beams and side beams, the disassembled transportation and efficient on-site assembly of large door frames are achieved, greatly reducing the requirements for transportation space and the difficulty of handling. The precise interlocking of the connecting ears and connecting slots provides initial positioning and radial constraint for the docking of each beam, effectively ensuring the geometric accuracy and form and position tolerances of the final assembled door frame. The subsequent bolt fixing provides strong axial locking force and connection reliability, ensuring that the door frame as a whole has sufficient structural strength and stability when bearing loads. At the same time, this structure also provides convenience for possible subsequent maintenance or component replacement.

[0024] Compared with the prior art, this utility model provides a protective door for civil defense projects, which has the following beneficial effects: The automatic raising and lowering of the threshold is achieved through a purely mechanical linkage structure, which completely solves the problems of traditional movable thresholds that require manual installation, are inconvenient to store, and are easy to lose. Its core transmission disc assembly and leaf spring design can effectively absorb the overtravel at the end of the door closing, cleverly avoiding the possibility of the mechanism jamming after the door jamb and threshold slot are locked. This ensures that the protective door can be opened smoothly in an emergency, thereby improving the emergency response speed and automation level of civil defense projects, while greatly enhancing the reliability and safety of the equipment. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Figure 1 This is a schematic diagram of the front structure of this utility model; Figure 2 This is a schematic diagram of the rear structure of the present invention; Figure 3 This is a schematic diagram of the door leaf in the unfolded state of this utility model; Figure 4 This is a schematic diagram of the threshold component structure of this utility model; Figure 5 This is a schematic diagram of the transmission disc assembly structure of this utility model; Figure 6 This is a schematic diagram of the keyway structure of this utility model.

[0026] In the diagram: 10, door frame; 20, rotating shaft; 30, door leaf; 310, locking block; 40, threshold assembly; 410, threshold; 411, slot; 420, drive shaft; 421, key; 430, threaded pair; 440, sliding shaft; 450, sliding sleeve; 50, transmission mechanism; 510, first bevel gear; 520, second bevel gear; 530, third bevel gear; 531, keyway; 540, transmission shaft; 550, transmission disc assembly; 551, transmission disc; 552, positioning shaft; 553, positioning groove; 554, leaf spring; 555, baffle. Detailed Implementation

[0027] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0028] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0029] Example: Please see Figures 1-6 This utility model provides a technical solution: a protective door for civil defense projects, including a door frame 10, a rotating shaft 20, and a door leaf 30 rotatably mounted on the door frame 10 via the rotating shaft 20. The door frame 10 is provided with a liftable threshold assembly 40. A transmission mechanism 50 is provided between the rotating shaft 20 and the threshold assembly 40. When the door leaf 30 is closed, the threshold assembly 40 can be driven to rise through the rotating shaft 20 and the transmission mechanism 50, and the door leaf 30 and the raised threshold assembly 40 are locked together.

[0030] Specifically, by setting up a transmission mechanism 50 linked to the rotating shaft 20 to drive the threshold assembly 40 to rise and fall, the threshold 410 is automatically and synchronously raised and locked during the closing of the door 30. This design significantly improves the sealing performance and overall protective effectiveness of the protective door. The precise cooperation between the transmission mechanism 50 and the threshold assembly 40 ensures that the threshold 410 is driven to the highest position only when the door 30 is nearly fully closed, and finally achieves reliable locking through the engagement of the locking block 310 and the locking groove 411. The elastic buffer in the transmission disc assembly 550 effectively absorbs the overload force and prevents the mechanism from jamming due to processing or installation errors. This ensures both the smoothness of the closing process and the reliability of the self-locking, and also ensures that the door 30 can be opened smoothly in an emergency, thereby comprehensively enhancing the automation, safety, and practical reliability of the civil defense project protective door.

[0031] Preferably, the threshold assembly 40 includes a threshold 410, a drive shaft 420, and a threaded pair 430; the threshold 410 is vertically mounted on the bottom of the door frame 10; the drive shaft 420 is rotatably mounted on the threshold 410, and a key 421 is provided on its lower half; the threaded pair 430 is fixed on the threshold 410 and threadedly connected to the upper half of the drive shaft 420.

[0032] Specifically, by fixing the threaded pair 430 to the sill 410 and forming a helical transmission with the drive shaft 420, when the drive shaft 420 is driven to rotate by the transmission mechanism 50, its own rotation can be efficiently and accurately converted into the linear lifting motion of the sill 410. The transmission is smooth and has a self-locking characteristic, ensuring the positional stability of the sill 410 after it is raised. At the same time, the key 421 structure set in the lower half of the drive shaft 420 allows it to slide relative to the third bevel gear 530 along the axial direction while transmitting torque, thereby seamlessly transmitting the rotational power to the entire vertically moving sill 410, realizing the decoupling of power transmission and component lifting, making the entire sill assembly 40 compact and reliable in linkage.

[0033] Preferably, the transmission mechanism 50 includes a first bevel gear 510, a second bevel gear 520, a third bevel gear 530, and a transmission shaft 540 assembly; the second bevel gear 520 is fixed to the bottom end of the rotating shaft 20; the transmission shaft 540 assembly is mounted on the door frame 10, and the first bevel gear 510 is provided at both ends, wherein the first bevel gear 510 at one end meshes with the second bevel gear 520; the third bevel gear 530 is slidably sleeved on the lower half of the drive shaft 420 and meshes with the first bevel gear 510 at the other end, and the inner hole of the third bevel gear 530 is provided with a keyway 531 that matches the key 421 of the drive shaft 420.

[0034] Specifically, by setting up a bevel gear transmission chain consisting of a first bevel gear 510, a second bevel gear 520, and a third bevel gear 530, and using the transmission shaft 540 assembly for power transmission, the rotation of the vertical rotating shaft 20 is cleverly converted into horizontal transmission, and finally into the rotation of the drive shaft 420, achieving two efficient and reliable changes in the direction of power transmission. In particular, the third bevel gear 530, through the sliding engagement of its inner hole keyway 531 with the key 421 on the drive shaft 420, allows the rotational power to be continuously transmitted to the drive shaft 420, while not hindering the necessary axial movement of the drive shaft 420 under the action of the threaded pair 430. This perfectly decouples the rotational motion from the lifting motion, ensuring that the entire transmission process is smooth, precise, and structurally stable and reliable.

[0035] Preferably, the drive shaft 540 assembly includes two coaxially arranged drive shafts 540 and a drive disc assembly 550 connected between the two drive shafts 540; the two drive shafts 540 are mounted on the door frame 10 through bearing seats, and a first bevel gear 510 is fixed to their outer ends respectively.

[0036] Specifically, by using two coaxial drive shafts 540 connected to a single torque-transmitting unit via a drive disc assembly 550, a long shaft is cleverly divided into two independently supported sections. This split structure effectively reduces the machining accuracy requirements of the bearing housing mounting surface on the door frame 10, simplifies the assembly process, and can adapt to minor deformations and installation errors, ensuring the flexibility and stability of the overall rotation of the drive shaft 540 assembly. At the same time, this design provides structural space for integrating a drive disc assembly 550 with buffering and overload protection functions between the two drive shafts 540, making power transmission smoother and more reliable, and improving the adaptability of the entire transmission system to working conditions.

[0037] Preferably, the transmission disk assembly 550 includes two transmission disks 551 respectively fixed to the ends of two transmission shafts 540, and an elastic buffer disposed between the two transmission disks 551; one of the transmission disks 551 is provided with a positioning shaft 552, and the other transmission disk 551 is provided with a positioning groove 553 that is clearance-fitted with the positioning shaft 552.

[0038] Specifically, by setting an elastic buffer between the two transmission discs 551 and utilizing the clearance fit between the positioning shaft 552 and the positioning groove 553, a flexible coupling mechanism with torque transmission, angle compensation, and overload protection functions is constructed. The elastic buffer can effectively absorb the impact energy at the end of the closing of the door leaf 30 and the overload force caused by manufacturing errors, preventing the mechanism from jamming. The fit between the positioning shaft 552 and the positioning groove 553, while allowing a certain radial and angular offset, ensures the synchronization of torque transmission and the alignment between the two transmission discs 551, thereby significantly improving the adaptability and operational reliability of the transmission system under conditions of installation errors or slight deformation.

[0039] Preferably, the elastic buffer is a set of leaf springs 554, and baffles 555 are fixed on the opposite surfaces of the two transmission discs 551 respectively, and the two ends of the leaf springs 554 abut against the baffles 555 of the two transmission discs 551 respectively.

[0040] Specifically, by employing multiple leaf springs 554 as elastic buffers, with their ends respectively abutting against baffles 555 fixed on the two transmission discs 551, a highly efficient and reliable circumferential buffer mechanism is constructed. The leaf springs 554, with their high stiffness and fatigue resistance, can provide precise and powerful elastic buffering at the end of the door leaf 30 closing, effectively absorbing impact energy and allowing limited relative rotation between the transmission discs 551, thereby preventing the mechanism from jamming. The design of the baffles 555 not only provides a stable support plane for the leaf springs 554, ensuring uniform force transmission and avoiding stress concentration, but also enables the buffer structure to withstand frequent compression and release, greatly improving the durability of the transmission disc assembly 550 and its long-term reliability under harsh working conditions.

[0041] Preferably, the threshold assembly 40 further includes a guide mechanism for limiting the displacement direction of the threshold 410. The guide mechanism includes a sliding shaft 440 fixed on the threshold 410 and a sliding sleeve 450 fixed on the door frame 10 and slidingly engaged with the sliding shaft 440.

[0042] Specifically, by setting up a guide mechanism consisting of a sliding shaft 440 fixed on the threshold 410 and a sliding sleeve 450 fixed on the door frame 10, precise linear guidance and stable lateral support are provided for the lifting and lowering movement of the threshold 410. This effectively prevents the threshold 410 from shifting, jamming, or shaking due to uneven force during the lifting and lowering process, ensuring the alignment accuracy and engagement reliability between the threshold 410 and the locking block 310 on the door leaf 30. This sliding friction pair structure is simple and reliable. It can not only effectively transfer and distribute the radial load borne by the drive shaft 420 and the threaded pair 430 to the door frame 10, improving the stress state of the core transmission components, but also significantly improve the running stability and structural durability of the entire threshold assembly 40 under frequent lifting and lowering movements.

[0043] Preferably, a slot 411 is provided on the side of the threshold 410, and a block 310 adapted to the slot 411 is fixed at the corresponding position of the door leaf 30. When the door leaf 30 is completely closed and the threshold 410 is raised to the highest position, the block 310 is embedded in the slot 411.

[0044] Specifically, by opening a slot 411 on the side of the threshold 410 and setting a matching locking block 310 at the corresponding position of the door leaf 30, a precise interlocking mechanical structure is formed at the moment when the door leaf 30 is fully closed and the threshold 410 is raised to the highest position. This design tightly integrates the door leaf 30 and the threshold 410 from originally independent components into a solid whole, greatly enhancing the overall structural rigidity and impact resistance of the protective door in the closed state. This rigid locking mechanism effectively prevents displacement or vibration that may occur between the door leaf 30 and the threshold 410 under external pressure or impact load, thereby significantly improving the airtightness and protection level of the civil defense project. At the same time, the mechanical interlocking structure is simple and reliable, and can achieve automatic locking and unlocking without additional operation.

[0045] Preferably, the door frame 10 consists of an upper door frame 10 crossbeam, a lower door frame 10 crossbeam, a left side beam, and a right side beam. The connection between the crossbeam and the side beam is made by connecting ears and connecting grooves, and fixed by bolts.

[0046] Specifically, by designing the door frame 10 as a modular, split structure composed of an upper door frame beam, a lower door frame beam, and left and right side beams, and by using connecting ears and connecting slots for interlocking and then fastening with bolts at the connection points between the beams and side beams, the large door frame 10 can be disassembled for transportation and efficiently assembled on-site, greatly reducing the requirements for transportation space and the difficulty of handling. The precise interlocking of the connecting ears and connecting slots provides initial positioning and radial constraints for the docking of each beam, effectively ensuring the geometric accuracy and form and position tolerances of the final assembled door frame 10. The subsequent bolt fixing provides strong axial locking force and connection reliability, ensuring that the door frame 10 as a whole has sufficient structural strength and stability when bearing loads. At the same time, this structure also provides convenience for possible subsequent maintenance or component replacement.

[0047] Working principle: When the door leaf 30 is closed, its rotation drives the second bevel gear 520 at the bottom to rotate via the rotating shaft 20. The power is transmitted to the drive shaft 540 and the drive disc assembly 550 on the same side via the first bevel gear 510 meshing with it. This assembly pushes the drive disc 551 on the other side through the leaf spring 554 inside, thereby transmitting torque to the drive shaft 540 and the first bevel gear 510 at the other end, and driving the third bevel gear 530 meshing with it to rotate. The third bevel gear 530 drives the drive shaft 420 to rotate through the keyway 531 and the key 421 on the drive shaft 420. Since the drive shaft 420 meshes with the threaded pair 430 fixed on the sill 410, the rotation... The motion is converted into a linear lifting of the threshold 410. During this process, the sliding shaft 440 and the sliding sleeve 450 provide precise guidance for the threshold 410. When the door 30 is close to being fully closed, the threshold 410 is just raised to its highest position. Subsequently, the slight over-closing displacement of the door 30 is absorbed by the compression deformation of the leaf spring 554 in the transmission disc assembly 550 to prevent the mechanism from jamming. Until the door 30 is fully closed, the locking block 310 on it is embedded in the locking groove 411 of the threshold 410 to achieve mechanical locking. When the door 30 is opened, the compressed leaf spring 554 first releases its stored energy to reset the transmission system. Only after the door 30 is opened to a certain angle does it begin to drive the threshold 410 to descend smoothly in the reverse direction.

[0048] 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 a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A protective door for civil defense projects, comprising a door frame (10), a rotating shaft (20), and a door leaf (30) rotatably mounted on the door frame (10) via the rotating shaft (20), characterized in that: The door frame (10) is provided with a liftable threshold assembly (40). A transmission mechanism (50) is provided between the rotating shaft (20) and the threshold assembly (40). When the door leaf (30) is closed, the threshold assembly (40) can be driven to rise through the rotating shaft (20) and the transmission mechanism (50), and the door leaf (30) and the raised threshold assembly (40) are locked together.

2. A protective door for civil defense projects according to claim 1, characterized in that: The threshold assembly (40) includes a threshold (410), a drive shaft (420), and a threaded pair (430); the threshold (410) is vertically mounted on the bottom of the door frame (10); the drive shaft (420) is rotatably mounted on the threshold (410), and a key (421) is provided on its lower half; the threaded pair (430) is fixed on the threshold (410) and threadedly connected to the upper half of the drive shaft (420).

3. A protective door for civil defense projects according to claim 2, characterized in that: The transmission mechanism (50) includes a first bevel gear (510), a second bevel gear (520), a third bevel gear (530), and a transmission shaft (540) assembly; the second bevel gear (520) is fixed to the bottom end of the rotating shaft (20); the transmission shaft (540) assembly is mounted on the door frame (10), and the first bevel gear (510) is provided at both ends, wherein the first bevel gear (510) at one end meshes with the second bevel gear (520); the third bevel gear (530) is slidably sleeved on the lower half of the drive shaft (420) and meshes with the first bevel gear (510) at the other end, and the inner hole of the third bevel gear (530) is provided with a keyway (531) adapted to the key (421) of the drive shaft (420).

4. A protective door for civil defense projects according to claim 3, characterized in that: The drive shaft (540) assembly includes two coaxial drive shafts (540) and a drive disk assembly (550) connected between the two drive shafts (540); the two drive shafts (540) are mounted on the door frame (10) through bearing seats, and the first bevel gear (510) is fixed to their outer ends respectively.

5. A protective door for civil defense projects according to claim 4, characterized in that: The transmission disk assembly (550) includes two transmission disks (551) respectively fixed to the ends of the two transmission shafts (540), and an elastic buffer disposed between the two transmission disks (551); one of the transmission disks (551) is provided with a positioning shaft (552), and the other transmission disk (551) is provided with a positioning groove (553) that is clearance-fitted with the positioning shaft (552).

6. A protective door for civil defense projects according to claim 5, characterized in that: The elastic buffer is a set of leaf springs (554), and baffles (555) are fixed on the opposite surfaces of the two transmission discs (551). The two ends of the leaf springs (554) abut against the baffles (555) of the two transmission discs (551).

7. A protective door for civil defense projects according to claim 2, characterized in that: The threshold assembly (40) further includes a guide mechanism for limiting the displacement direction of the threshold (410), the guide mechanism including a sliding shaft (440) fixed on the threshold (410) and a sliding sleeve (450) fixed on the door frame (10) and slidingly engaging with the sliding shaft (440).

8. A protective door for civil defense projects according to any one of claims 1 to 7, characterized in that: The threshold (410) has a slot (411) on its side, and the door leaf (30) has a corresponding block (310) that is compatible with the slot (411). When the door leaf (30) is completely closed and the threshold (410) is raised to the highest position, the block (310) is embedded in the slot (411).

9. A protective door for civil defense projects according to any one of claims 1 to 7, characterized in that: The door frame (10) consists of an upper door frame (10) crossbeam, a lower door frame (10) crossbeam, a left side beam, and a right side beam. The crossbeam and the side beam are connected by connecting ears and connecting slots and fixed by bolts.

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