Novel embedded sleeve combined steel formwork for air defense door frame

Abstract

The utility model relates to a novel civil air defence door frame pre -buried sleeve pipe combined steel form, including front formwork subassembly, rear formwork subassembly and a plurality of pre -buried sleeve pipes, and front formwork subassembly and rear formwork subassembly all include a pair of left, right distribution's vertical formwork, and a block horizontal formwork is established between a pair of vertical formwork top, and the inside end between the vertical formwork of front, rear formwork subassembly component is located same side and is equipped with inside end closing plate, and the inside end face of vertical formwork and the outside end face of inside end closing plate are pasted together, and the horizontal formwork bottom between the horizontal formwork of front, rear formwork subassembly component is equipped with top closing plate, and top closing plate and inside end closing plate are perpendicular distribution, and the left and right two ends bottom surface of top closing plate respectively with the top surface of inside end closing plate located same side are pasted together. The utility model effectively improves the size accuracy of the civil air defence door frame wall after pouring concrete, makes the right angle of civil air defence door frame wall left, right inside end, the right angle of civil air defence door frame wall top left, right two ends all get good guarantee, avoids the normal installation of subsequent civil air defence door frame being affected.

Description

Technical Field

[0001] This utility model relates to a novel combination steel formwork for pre-embedded sleeves in civil defense door frames. Background Technology

[0002] Civil defense doors are the entrances and exits of civil defense projects. As my country develops and the country attaches greater importance to civil defense, people's awareness of safety and prevention is increasing, and the quality standards for civil defense projects are becoming higher. On December 29, 2024, the National Civil Air Defense Office issued and implemented the "General Technical Requirements for Civil Air Defense Protective Equipment (Protective Doors)".

[0003] Developed based on general technical requirements, the air-raid shelter door employs an innovative construction process where the wall is poured first, followed by the installation of the door frame. An air-raid shelter door typically consists of a door frame and a door body. The door frame is secured to pre-drilled holes in the air-raid shelter door frame wall using fasteners. To achieve higher quality standards and greater efficiency in implementing the "General Technical Requirements for Civil Air Defense Protective Equipment (Protective Doors)," the construction of the air-raid shelter door frame wall typically involves first erecting a pouring formwork, then binding reinforcing bars and installing pre-embedded sleeves inside the formwork. After the concrete is poured, these pre-embedded sleeves become the pre-drilled holes for installing the air-raid shelter door frame, which are then secured with tie rods.

[0004] The existing formwork for the pouring of civil defense door frame walls is usually wooden formwork erected on site, or steel formwork prefabricated in the factory. Erecting wooden formwork on site is not only time-consuming, but also results in poor dimensional accuracy of the civil defense door frame wall after pouring. Steel formwork includes front formwork components and rear formwork components. Both the front and rear formwork components include a pair of vertical formworks distributed on the left and right. A horizontal formwork is set between the upper ends of the pair of vertical formworks. The pair of vertical formworks and the horizontal formwork form a door frame structure.

[0005] However, when steel formwork is used for pouring the formwork of the air-raid shelter door frame wall, no sealing plate is installed between the inner ends of the vertical formwork on the same side of the front and rear formwork components. Usually, a wooden formwork is temporarily erected on site, and the pouring area is enclosed by the wooden formwork and the two vertical side plates on the same side. The right angle position of the air-raid shelter door frame wall poured in this way has the problem of insufficient dimensional accuracy. For example, the right angles of the left and right inner ends of the air-raid shelter door frame wall (i.e., the right angle between the left inner side and the front and rear sides, and the right inner side of the right side and the front and rear sides) cannot be well guaranteed, and non-right angle structures are prone to occur. At the same time, many horizontal formworks are composed of multiple spliced ​​pieces, which makes it possible to form many splicing seams at the corner splicing of the top left and right ends, which can easily form steps. This makes it impossible to guarantee the right angle at the corners of the top left and right ends after pouring, and non-right angle structures are prone to occur. The aforementioned two situations result in suboptimal position, dimensions, flatness, and verticality of the pre-embedded sleeves in the civil defense door frame. These issues fail to meet the requirements of the "Notice from the National Civil Air Defense Office on Issuing the General Technical Requirements for Civil Air Defense Protective Equipment (Protective Doors)," which came into effect on January 1, 2025. This leads to deviations during subsequent installation of the civil defense door frame after demolding, affecting normal installation. Therefore, it is necessary to improve this technical aspect. Utility Model Content

[0006] This utility model addresses the problems existing in the prior art by providing a novel combination steel template for pre-embedded sleeves of civil defense door frames. The template is reasonably designed, improves the positional accuracy of the pre-embedded sleeves of civil defense doors, and avoids deviations during the installation of civil defense door frames after subsequent demolding.

[0007] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a novel combination steel formwork for pre-embedded sleeves of civil defense door frames, comprising a front formwork assembly, a rear formwork assembly, and multiple pre-embedded sleeves distributed between the front and rear formwork assemblies. Each of the front and rear formwork assemblies includes a pair of vertical formworks distributed on the left and right. A horizontal formwork is provided between the tops of the pair of vertical formworks. An inner sealing plate is provided between the inner ends of the vertical formworks on the same side of the front and rear formwork assemblies, and the inner end face of the vertical formwork is in contact with the outer end face of the inner sealing plate. A top sealing plate is horizontally provided between the bottom of the horizontal formwork of the front formwork assembly and the horizontal formwork of the rear formwork assembly. The top sealing plate is perpendicular to the inner sealing plate, and the bottom surfaces of the left and right ends of the top sealing plate are respectively in contact with the top surfaces of the inner sealing plates on the same side.

[0008] Furthermore, multiple pre-embedded sleeves are provided between the vertical templates on the same side of the front template assembly and the rear template assembly, and between the horizontal templates of the front template assembly and the horizontal templates of the rear template assembly.

[0009] Furthermore, each vertical template and horizontal template is provided with a positioning cylinder corresponding to the position of the pre-embedded sleeve. The positioning cylinder located on the front side and the positioning cylinder located on the rear side extend into the front and rear ports of the pre-embedded sleeve, respectively. The end of the positioning cylinder that is close to the interior of the pre-embedded sleeve is truncated cone-shaped.

[0010] Furthermore, a connecting screw is axially inserted into the pre-embedded sleeve. The front and rear ends of the connecting screw pass through the positioning cylinder on the same side and are locked and fixed to the positioning cylinder on the same side by fasteners. The fasteners include a locking washer and a locking nut. The locking washer contacts the end face of the positioning cylinder away from the pre-embedded sleeve. A clearance hole is opened in the middle of the locking washer to facilitate the passage of the connecting screw. The locking nut is screwed to the connecting screw and abuts against the end face of the locking washer away from the positioning cylinder.

[0011] Furthermore, the front and rear ends of the inner sealing plate are respectively connected to the vertical template located on the same side via a first connector; the left and right end faces of the top sealing plate are respectively flush with the outer end faces of the inner sealing plate located on the same side; the bottom surface of the horizontal template is in contact with the top surface of a pair of vertical templates located on the same side; and the front and rear ends of the top sealing plate are respectively connected to the horizontal template located on the same side via a second connector.

[0012] Furthermore, the front end face of the vertical template of the front template assembly and the rear end face of the vertical template of the rear template assembly are each provided with a pair of first angle irons distributed on the left and right. The first angle irons are vertically arranged, and the horizontal edges of the first angle irons are fixedly connected to the vertical template. The longitudinal edges of the pair of first angle irons are respectively flush with the left and right sides of the vertical template. The inner side of the inner sealing plate is provided with a pair of second angle irons symmetrically distributed in front and back. The second angle irons are vertically arranged, and the positions of the second angle irons and the first angle irons correspond to those of the first angle irons. The longitudinal edges of the second angle irons, the inner sealing plate, and the longitudinal edges of the first angle irons on the same side are connected by a first connector.

[0013] Furthermore, the first connector includes a plurality of first connecting bolts distributed vertically. The first connecting bolts pass through the longitudinal edge of the second angle iron, the inner sealing plate, and the longitudinal edge of the first angle iron on the same side, and are then locked with the first nut.

[0014] Furthermore, the outer side of the horizontal template is provided with a pair of upper and lower triangular irons, the third triangular irons are arranged horizontally, the vertical side of the third triangular irons is fixedly connected to the horizontal template, and the longitudinal side of the third triangular irons is in contact with the top surface of the top sealing plate; the bottom surface of the top sealing plate is provided with a pair of front and rear distributed fourth triangular irons, the fourth triangular irons are arranged horizontally, and the longitudinal side of the fourth triangular irons, the top sealing plate, and the longitudinal side of the triangular irons on the same side are connected by a second connector.

[0015] Furthermore, the second connector includes a plurality of second connecting bolts distributed laterally. The second connecting bolts pass through the longitudinal edge of the third angle iron, the top sealing plate, and the longitudinal edge of the fourth angle iron located on the same side, and then engage with the second nut to lock it in place.

[0016] Furthermore, a pair of horizontal connecting plates distributed on the left and right are provided below the first triangular iron at the lower end of the horizontal template. The horizontal connecting plates are vertically fixed to the upper end of the vertical template on the same side. The horizontal connecting plates and the longitudinal edge of the third angle iron are locked together by a vertically set third connecting bolt and a third nut.

[0017] Compared with the prior art, the present invention has the following advantages: The present invention has a reasonable structural design, which effectively improves the dimensional accuracy of the air-raid shelter door frame wall after concrete pouring, and ensures that the right angles of the left and right inner ends of the air-raid shelter door frame wall and the right angles of the top left and right ends of the air-raid shelter door frame wall are well guaranteed. The present invention can more accurately position the position, size, flatness and verticality of the air-raid shelter door frame pre-embedded sleeve, and avoid the normal installation of the air-raid shelter door frame after subsequent demolding. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the main structure of an embodiment of this utility model;

[0019] Figure 2 This is a side view of an embodiment of the present invention.

[0020] Figure 3 This is a top view of an embodiment of the present invention.

[0021] Figure 4 yes Figure 1 Enlarged diagram of point A in the diagram;

[0022] Figure 5 This is a schematic cross-sectional view of the installation of the pre-embedded sleeve according to an embodiment of this utility model;

[0023] Figure 6 yes Figure 5 Enlarged diagram of point B in the diagram;

[0024] Figure 7 yes Figure 5 Enlarged diagram of point C in the diagram;

[0025] Figure 8 This is a schematic diagram of the cooperation between the horizontal template and the top sealing plate in an embodiment of this utility model;

[0026] Figure 9 yes Figure 8 Enlarged diagram of point D in the diagram;

[0027] Figure 10This is a schematic diagram of the cooperation between the top sealing plate and the inner sealing plate in an embodiment of this utility model;

[0028] Figure 11 This is a schematic diagram of the structure of the pre-embedded sleeve in an embodiment of this utility model;

[0029] Figure 12 This is a schematic diagram of the structure of the positioning cylinder in an embodiment of this utility model;

[0030] Figure 13 This is a cross-sectional schematic diagram of the civil defense door frame wall after it has been poured. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0032] In the description of this utility model, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0033] like Figures 1-12As shown, this utility model discloses a novel combination steel formwork for pre-embedded sleeves of civil defense door frames. It is designed based on the "Notice of the National Civil Air Defense Office on Issuing the General Technical Requirements for Civil Air Defense Protection Equipment (Protective Doors)" which came into effect on January 1, 2025. The overall structure is a door-shaped frame structure, specifically including a front formwork assembly 1 and a rear formwork assembly 2 arranged in parallel and spaced order, and multiple pre-embedded sleeves 3 distributed between the front formwork assembly 1 and the rear formwork assembly 2. There are multiple pre-embedded sleeves 3. After pouring, the pre-embedded sleeves 3 form reserved holes for installing the civil defense door frame. The reserved holes are locked to the civil defense door frame by tie rods 27. The front template assembly 1 and the rear template assembly 2 have the same structure and each includes a pair of vertical templates 11 distributed on the left and right. The vertical templates 11 are arranged horizontally. A horizontal template 12 is provided between the tops of the pair of vertical templates 11 in the front template assembly 1 and between the tops of the pair of vertical templates 11 in the rear template assembly 2. An inner seal is provided between the inner ends of the vertical templates 11 on the same side of the front template assembly 1 and the rear template assembly 2 (such as the vertical template on the left and the vertical template on the right). The inner end face of the vertical template 11 is attached to the outer end face of the inner sealing plate 13. The front and rear ends of the inner sealing plate 13 are respectively connected and fixed to the vertical template 11 located on the same side. A top sealing plate 18 is horizontally arranged between the bottom of the horizontal template 12 of the front template assembly 1 and the horizontal template 12 of the rear template assembly 2. The top sealing plate 18 is perpendicular to the inner sealing plate 13. The bottom surfaces of the left and right ends of the top sealing plate 18 are respectively attached to the top surfaces of the inner sealing plate 13 located on the same side.

[0034] In this combined steel formwork, the inner sealing plate spans the vertical formwork located on the same side longitudinally, and the front and rear ends of the inner sealing plate are connected and fixed to the vertical formwork. This formwork can effectively ensure the right angle between the inner sealing plate and the vertical formwork located on the same side, so that the right angle 29 (i.e., the right angle 29 between the inner side of the left end and the front and rear sides, and the right angle 29 between the inner side of the right end and the front and rear sides) of the left and right inner ends of the air-raid shelter door frame wall after the concrete is poured is well guaranteed. At the same time, the flatness of the end face 28 where the front and rear ends of the pre-embedded sleeve are located is good, so as to avoid affecting the normal installation of the air-raid shelter door frame after the formwork is removed. The horizontal formwork with an integral structure spans above a pair of vertical formworks, and the top sealing plate spans the top surface of the inner sealing plates on both sides. This reduces the splicing seams at the right angles at the upper left and right ends of the entire combined steel formwork, avoiding the formation of steps. This ensures that the right angles at the top left and right ends of the poured civil defense door frame wall (i.e., the right angle between the inner side of the left end and the top surface, and the right angle between the inner side of the right end and the top surface) are well guaranteed, preventing the normal installation of the civil defense door frame from being affected after subsequent demolding.

[0035] In this embodiment, multiple pre-embedded sleeves 3 are provided between the vertical template 11 on the same side of the front template assembly 1 and the rear template assembly 2, and between the horizontal template 12 of the front template assembly 1 and the horizontal template 12 of the rear template assembly 2.

[0036] In this embodiment, each vertical template 11 and horizontal template 12 is provided with a positioning cylinder 4 corresponding to the position of the pre-embedded sleeve 3. The number of positioning cylinders 4 on the front template assembly 1 and the rear template assembly 2 corresponds to the number of pre-embedded sleeves 3. The positioning cylinder 4 located on the front side and the positioning cylinder 4 located on the rear side extend into the front and rear ports of the pre-embedded sleeve 3, respectively. That is, the pre-embedded sleeve 3 is sandwiched between the front template assembly 1 and the rear template assembly 2, such as between the vertical templates of the front and rear template assemblies located on the same side, or between the horizontal templates of the front and rear template assemblies.

[0037] In this embodiment, the end of the positioning cylinder 4 that is close to the interior of the pre-embedded sleeve 3 is truncated cone-shaped, that is, the outer surface of the end of the positioning cylinder that is close to the pre-embedded sleeve is conical 5, so as to better extend into the port of the pre-embedded sleeve.

[0038] In this embodiment, a connecting screw 6 is axially inserted into the pre-embedded sleeve 3. The front and rear ends of the connecting screw 6 pass through the positioning cylinder 4 located on the same side and are locked and fixed to the positioning cylinder 4 located on the same side by fasteners. That is, the pre-embedded sleeve 3 is firmly clamped and fixed in the front and rear directions by the front template assembly 1 and the rear template assembly 2. The front and rear ends of the pre-embedded sleeve are inserted and positioned by the positioning cylinder, and then the pre-embedded sleeve is locked and fixed in the front and rear directions. This achieves that the pre-embedded sleeve is firmly clamped between the front template assembly 1 and the rear template assembly 2 distributed in the front and rear. When the pre-embedded sleeve is impacted by the concrete during concrete pouring, it is not easy for it to move or shift. This improves the positional accuracy of the reserved hole obtained after concrete pouring and avoids affecting the normal installation of the civil defense door frame.

[0039] In this embodiment, the vertical template 11 and horizontal template 12 of the front template assembly 1 and the rear template assembly 2 are provided with longitudinal through holes corresponding to the positions of the pre-embedded sleeve 3. The positioning cylinder 4 passes through the longitudinal through hole and is welded and fixed to the longitudinal through hole.

[0040] In this embodiment, the fastener includes a locking washer 7 and a locking nut 8. The locking washer 7 is in contact with the end face of the positioning cylinder 4 away from the pre-embedded sleeve 3. The locking washer 7 has a clearance hole in the middle to facilitate the passage of the connecting screw 6. The locking nut 8 is screwed to the connecting screw 6. The locking nut 8 abuts against the end face of the locking washer 7 away from the positioning cylinder 4, and is used to lock and fix the fastener.

[0041] In this embodiment, the embedded sleeve 3 is a circular steel pipe. Circular end flanges 9 are fixed to the outer sides of both the front and rear ends of the embedded sleeve 3. The end flanges 9 at the front and rear ends of the embedded sleeve 3 are respectively fitted to the front template 1 and the rear template 2. To improve structural strength, a circular intermediate flange 10 is fixed to the outer surface of the middle part of the embedded sleeve 3.

[0042] In this embodiment, the front and rear ends of the inner sealing plate 13 are respectively connected to the vertical template 11 located on the same side via a first connector; the left and right end faces of the top sealing plate 18 are respectively flush with the outer end faces of the inner sealing plate 13 located on the same side; the bottom surface of the horizontal template 12 is in contact with the top surface of a pair of vertical templates 11 located on the same side; and the front and rear ends of the top sealing plate 18 are respectively connected to the horizontal template 12 located on the same side via a second connector.

[0043] In this embodiment, both the front end face of the vertical template 11 of the front template assembly 1 and the rear end face of the vertical template 11 of the rear template assembly 2 are provided with a pair of left and right distributed first angle irons 14. The first angle irons 14 are vertically arranged, and their horizontal edges are welded and fixed to the vertical template 11. The longitudinal edges of the pair of first angle irons 14 are flush with the left and right sides of the vertical template 11, respectively. This structure, combining the first angle irons with the vertical template, uses a 90-degree integrally formed angle iron, which facilitates better right-angle formation after concrete pouring. Traditionally, the vertical template is bent at 90 degrees at both ends to form folded edges. In this method, there is a certain rounded corner between the folded edges and the vertical template, making it difficult to guarantee a right angle after concrete pouring.

[0044] In this embodiment, the inner side of the inner sealing plate 13 is provided with a pair of second angle irons 15 symmetrically distributed in front and back. The second angle irons 15 are arranged vertically and correspond to the positions of the first angle iron 14. The longitudinal edge of the second angle iron 15, the inner sealing plate 13 and the longitudinal edge of the first angle iron 14 located on the same side are connected by a first connector.

[0045] In this embodiment, the first connector includes a plurality of first connecting bolts 16 distributed vertically. The first connecting bolts 16 pass through the longitudinal edge of the second angle iron 15, the inner sealing plate 13 and the longitudinal edge of the first angle iron 14 located on the same side, and are then locked with the first nut 17.

[0046] In this embodiment, the outer side of the horizontal template 12 is provided with a pair of upper and lower distributed triangular irons 19. The triangular irons 19 are arranged horizontally, and the vertical side of the triangular irons 19 is welded and fixed to the horizontal template 12. The longitudinal side of the triangular irons 19 is in contact with the top surface of the top sealing plate 18. The bottom surface of the top sealing plate 18 is provided with a pair of front and rear distributed fourth angle irons 20. The fourth angle irons 20 are arranged horizontally, and the longitudinal side of the fourth angle irons 20, the top sealing plate 18, and the longitudinal side of the triangular irons 19 located on the same side are connected by a second connector.

[0047] In this embodiment, the second connector includes a plurality of second connecting bolts 21 distributed laterally. The second connecting bolts 21 pass through the longitudinal edge of the third angle iron 19, the top sealing plate 18 and the longitudinal edge of the fourth angle iron 20 located on the same side, and are then locked with the second nut 22.

[0048] In this embodiment, a pair of horizontal connecting plates 23 distributed on the left and right are provided below the triangular iron 19 located at the lower end of the horizontal template 12. The horizontal connecting plates 23 are vertically fixed to the upper end of the vertical template 11 located on the same side. The horizontal connecting plates 23 and the longitudinal edge of the third angle iron 19 are locked together by a vertically arranged third connecting bolt 24 and a third nut 25.

[0049] In this embodiment, a transverse reinforcing rod 26 is fixed between the lower ends of a pair of vertical templates 11 in the front template assembly 1 and between the lower ends of a pair of vertical templates 11 in the rear template assembly 2.

[0050] This combined steel formwork is designed based on the "Notice of the National Civil Air Defense Office on Issuing the General Technical Requirements for Civil Air Defense Protective Equipment (Protective Doors)" which came into effect on January 1, 2025. It achieves more precise positioning of the location, dimensions, flatness, and verticality of the embedded sleeves in the civil air defense door frame by combining various elements such as the inner sealing plates between vertical formwork sections, the top sealing plates between the bottom of horizontal formwork sections, the coordination between the top and inner sealing plates, the connection relationships between vertical formwork sections, the connection relationships between horizontal formwork sections and the top sealing plates, and the fixing methods of the pre-embedded sleeves. The combined steel formwork complies with the requirements of the "Notice of the National Civil Air Defense Office on Issuing the General Technical Requirements for Civil Air Defense Protective Equipment (Protective Doors)".

[0051] If this utility model discloses or relates to mutually fixedly connected parts or structural components, then, unless otherwise stated, a fixed connection can be understood as: a detachable fixed connection (e.g., using bolts or screws), or a non-detachable fixed connection (e.g., riveting, welding). Of course, mutually fixed connections can also be replaced by an integral structure (e.g., manufactured using a casting process) (except where it is obviously impossible to use an integral forming process).

[0052] In addition, unless otherwise stated, the terms used to indicate positional relationships or shapes in any of the technical solutions disclosed in this utility model above include states or shapes that are similar to, close to, or approximate with them.

[0053] Any component provided by this utility model can be assembled from multiple individual components, or it can be a single component manufactured by a one-piece molding process.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it; although the utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of this utility model or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solution of this utility model, and all such modifications and substitutions should be covered within the scope of the technical solution claimed by this utility model.

Claims

1. A new type of embedded sleeve combined steel formwork for human defense door frame, comprising a front formwork assembly, a rear formwork assembly and a plurality of embedded sleeves distributed between the front formwork assembly and the rear formwork assembly, characterized in that: Both the front template assembly and the rear template assembly include a pair of vertical templates distributed on the left and right. A horizontal template is provided between the top of the pair of vertical templates. An inner sealing plate is provided between the inner ends of the vertical templates on the same side of the front template assembly and the rear template assembly. The inner end face of the vertical template is in contact with the outer end face of the inner sealing plate. A top sealing plate is horizontally provided between the bottom of the horizontal templates of the front template assembly and the horizontal templates of the rear template assembly. The top sealing plate is perpendicular to the inner sealing plate. The bottom surfaces of the left and right ends of the top sealing plate are respectively in contact with the top surfaces of the inner sealing plates on the same side.

2. The new type of embedded sleeve combined steel formwork for air defense door frame according to claim 1, characterized in that: Multiple pre-embedded sleeves are provided between the vertical templates on the same side of the front template assembly and the rear template assembly, and between the horizontal templates of the front template assembly and the horizontal templates of the rear template assembly.

3. The novel civil defense door frame pre-embedded sleeve combined steel formwork according to claim 2, characterized in that: Each vertical and horizontal template is equipped with a positioning cylinder corresponding to the position of the pre-embedded sleeve. The positioning cylinder located on the front side and the positioning cylinder located on the rear side extend into the front and rear ports of the pre-embedded sleeve, respectively. The end of the positioning cylinder that is close to the inside of the pre-embedded sleeve is truncated cone-shaped.

4. The novel civil defense door frame pre-embedded sleeve combined steel formwork according to claim 3, characterized in that: A connecting screw is axially inserted into the pre-embedded sleeve. The front and rear ends of the connecting screw pass through the positioning cylinders located on the same side and are locked and fixed to the positioning cylinders located on the same side by fasteners. The fasteners include a locking washer and a locking nut. The locking washer contacts the end face of the positioning cylinder away from the pre-embedded sleeve. A clearance hole is opened in the middle of the locking washer to facilitate the passage of the connecting screw. The locking nut is screwed to the connecting screw and abuts against the end face of the locking washer away from the positioning cylinder.

5. The novel civil defense door frame pre-embedded sleeve combined steel formwork according to claim 1, characterized in that: The front and rear ends of the inner sealing plate are connected to the vertical templates on the same side via a first connector; the left and right ends of the top sealing plate are flush with the outer ends of the inner sealing plate on the same side; the bottom surface of the horizontal template is in contact with the top surface of a pair of vertical templates on the same side; and the front and rear ends of the top sealing plate are connected to the horizontal templates on the same side via a second connector.

6. The novel civil defense door frame pre-embedded sleeve combined steel formwork according to claim 5, characterized in that: The front end face of the vertical template of the front template assembly and the rear end face of the vertical template of the rear template assembly are each provided with a pair of first angle irons distributed on the left and right. The first angle irons are vertically arranged, and the horizontal edges of the first angle irons are fixedly connected to the vertical template. The longitudinal edges of the pair of first angle irons are respectively flush with the left and right sides of the vertical template. The inner side of the inner sealing plate is provided with a pair of second angle irons symmetrically distributed in front and back. The second angle irons are vertically arranged, and the positions of the second angle irons and the first angle irons are corresponding. The longitudinal edges of the second angle irons, the inner sealing plate, and the longitudinal edges of the first angle irons on the same side are connected by a first connector.

7. The novel civil defense door frame pre-embedded sleeve combined steel formwork according to claim 6, characterized in that: The first connector includes a plurality of first connecting bolts distributed vertically. The first connecting bolts pass through the longitudinal edge of the second angle iron, the inner end plate, and the longitudinal edge of the first angle iron on the same side, and are then locked with the first nut.

8. The novel civil defense door frame pre-embedded sleeve combined steel formwork according to claim 5, characterized in that: The outer side of the horizontal template is provided with a pair of upper and lower triangular irons. The third triangular iron is arranged horizontally, and its vertical side is fixedly connected to the horizontal template. The longitudinal side of the third triangular iron is in contact with the top surface of the top sealing plate. The bottom surface of the top sealing plate is provided with a pair of front and rear fourth triangular irons. The fourth triangular irons are arranged horizontally, and their longitudinal sides, the top sealing plate, and the longitudinal sides of the triangular irons on the same side are connected by a second connector.

9. The novel civil defense door frame pre-embedded sleeve combined steel formwork according to claim 8, characterized in that: The second connector includes a plurality of second connecting bolts distributed laterally. The second connecting bolts pass through the longitudinal edge of the third angle iron, the top end plate, and the longitudinal edge of the fourth angle iron located on the same side, and are then engaged with the second nut to lock in place.

10. The novel civil defense door frame pre-embedded sleeve combined steel formwork according to claim 8, characterized in that: A pair of horizontal connecting plates, one on the left and one on the right, are provided below the first triangular iron at the lower end of the horizontal template. The horizontal connecting plates are vertically fixed to the upper end of the vertical template on the same side. The horizontal connecting plates and the longitudinal edge of the third angle iron are locked together by a third connecting bolt and a third nut set vertically.

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