Sleeve pup joint compensation device
By designing a casing short-circuit compensation device including short-circuit expansion tube and positioning plate, the problem that traditional casing compensator is difficult to deal with the composite direction displacement, and the multi-directional displacement processing capability and improvement of the pipe body stability is achieved.
Patent Information
- Application Number
- CN202421637614.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-11
- Publication Date
- 2025-06-13
- Estimated Expiration
- 2034-07-11
AI Technical Summary
Traditional casing compensators mainly compensate for the axial displacement of linear pipes, making it difficult to effectively deal with the displacement in the transverse, angular or composite directions, and cannot meet the needs of complex pipeline systems in modern industry.
A short-circuit compensation device for sleeves is designed, including components such as the left connecting plate, the right connecting plate, the connecting pipe body, the short-circuit expansion tube and the positioning plate. By setting the short-circuit expansion tube and the positioning plate, the multi-directional displacement and change direction of the connecting plate are realized, and the stability of the pipe body is enhanced.
The device can provide additional flexibility in the longitudinal and transverse directions, adapt to complex spatial displacement needs, realize multi-directional displacement processing capability, and improve the stability and adaptability of the pipeline system.
Smart Images
Figure CN222977709U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of compensators, and particularly relates to a casing short joint compensation device. Background Art
[0002] The casing compensator is an important device for solving pipeline deformation caused by temperature changes or mechanical vibrations. In multiple industrial fields, such as chemical industry, metallurgy, etc., they are widely used in various pipeline transportation systems. These compensators mainly consist of bellows and accessories such as end pipes, brackets, flanges, and conduits, jointly forming a complete compensation system.
[0003] As a key engineering device, the casing compensator is designed and applied to address pipeline system deformation problems caused by temperature fluctuations and mechanical vibrations. The wide application of this device covers multiple heavy industrial fields such as chemical industry, metallurgy, petroleum, and power, and is crucial for ensuring the safe operation of the pipeline system. They can not only maintain the stability of the system but also reduce maintenance costs and downtime, thereby improving the overall operation efficiency. Looking deeper, the structural design of the compensator is very delicate, and the elastic deformation ability of the core component, the bellows, is the basis for its function realization. Through a series of folding designs, the bellows can elongate or shorten in length, and this deformation ability can effectively offset the expansion or contraction of the pipeline caused by temperature changes. At the same time, with the cooperation of auxiliary components such as end pipes, brackets, flanges, and conduits, the entire system can work more stably, ensuring its function under various pressure conditions.
[0004] However, the functions of traditional casing compensators have certain limitations. They mainly compensate for axial displacement of straight pipelines and have weak capabilities in dealing with lateral, angular, or composite-direction displacements. With the development of modern industry, the design of pipeline systems is becoming increasingly complex, and a single-direction compensation mechanism is no longer sufficient to meet actual needs.
[0005] Therefore, researchers and engineers are working on developing a new generation of casing compensators, aiming to enable the compensator to not only handle single-direction displacements but also process multi-dimensional deformations in space and automatically adjust the compensation strategy according to real-time conditions. Content of the Utility Model
[0006] The purpose of the utility model is to provide a casing short joint compensation device with wide applicability and convenient adaptation to the multi-directional adaptability of pipelines for the above problems.
[0007] To achieve the above object, the present utility model discloses a casing stub compensation device, which includes a left connection disk and a right connection disk. Two connection plates are respectively arranged on the inner end faces of the left connection disk and the right connection disk. The structural feature is that a connection pipe body is arranged between the left connection disk and the right connection disk. The first stub expansion pipe and the second stub expansion pipe connected to the left connection disk and the right connection disk are respectively arranged at the left and right ends of the connection pipe body. The first positioning plate and the second positioning plate connected to the left and right connection plates are respectively arranged on the front and back sides of the connection pipe body. The first hinge seat and the second hinge seat are respectively arranged at the left ends of the first positioning plate and the second positioning plate. The second hinge seat and the first hinge seat are respectively arranged at the right ends of the first positioning plate and the second positioning plate.
[0008] After adopting the above structure, by arranging the first stub expansion pipe and the second stub expansion pipe on the connection pipe body and connecting them to the left connection disk and the right connection disk respectively, the left connection disk and the right connection disk at the left and right ends can have a certain displacement processing ability in multiple directions. The first positioning plate and the second positioning plate arranged on the front and back sides of the connection pipe body are hinged to the connection plates on the left connection disk and the right connection disk, which can effectively improve the overall stability of the pipe body and also realize the direction change of the two connection disks of the device. By arranging the first hinge seat and the second hinge seat at both ends of the positioning plate, it is convenient for the left connection disk to displace up and down at a relatively large distance relative to the right connection disk and displace up and down at a relatively small distance relative to the connection pipe body. At the same time, it is convenient for the left connection disk to displace backward at a relatively large distance relative to the right connection disk and displace forward at a relatively small distance relative to the connection pipe body.
[0009] Preferably, the two connection plates on the inner end faces of the left connection disk and the right connection disk are respectively vertically connected to the connection disk body and are located on the front and back sides of the expansion pipe body. A plurality of hinge notches are arranged at intervals along the width direction at the outer ends of the connection plates. The hinge notches arranged at the outer ends of the connection plates facilitate the hinge connection with the first hinge seat and the second hinge seat and have strong anti-deformation ability.
[0010] Preferably, both the first stub expansion pipe and the second stub expansion pipe are corrugated pipes, and the sizes of the two corrugated pipes are the same and are adapted to the diameter of the connection pipe body. The front and back ends of the first stub expansion pipe are respectively fixed on the rear end face of the right connection disk and the right end face of the connection pipe body. The front and back ends of the second stub expansion pipe are respectively fixed on the left end face of the connection pipe body and the rear end face of the left connection disk. By setting the first stub expansion pipe and the second stub expansion pipe as corrugated pipe structures, it can effectively facilitate the right connection disk and the left connection disk to adapt to the stress in different directions.
[0011] Preferably, the first positioning plate and the second positioning plate are strip-shaped plates with a width size adapted to the width of the connecting plate, and the length of the strip-shaped plate body is adapted to the distance between the two connecting plates on the left connecting disk and the right connecting disk. The adaptation of the first positioning plate and the second positioning plate to the connecting plate can effectively improve the stability when the two are hinged, and also make the displacement processing ability in the composite direction more flexible.
[0012] Preferably, the first hinge seat includes a first positioning column provided on the outer end face of the first positioning plate or the second positioning plate, and a first circular limiting plate parallel to the plate body of the first positioning plate or the second positioning plate is provided on the outer end face of the first positioning column. The diameter of the first positioning column is smaller than the diameter of the first circular limiting plate. A first hinge plate is sleeved on the first positioning column, and a plurality of first hinge bases are provided on the outer end face of the first hinge plate near the connecting disk end. By sleeving the first hinge plate on the first positioning column and preventing the first hinge plate from falling off through the first circular limiting plate, the up-and-down swing of the first hinge plate can be realized, and the front-and-back swing of the connecting plate hinged on the first hinge base can be realized by the first hinge base provided on the outer end face of the first hinge plate.
[0013] Preferably, the plurality of first hinge bases are arranged at intervals along the width direction of the first hinge plate, and a through hole passing through the upper and lower end faces is provided on each first hinge base. A circular limiting hole adapted to the diameter of the first positioning column is provided in the middle of the first hinge plate, and a sink adapted to the first circular limiting plate is provided on the outer end face of the first hinge plate at the circular limiting hole. The height of the first positioning column is adapted to the thickness of the first hinge plate. By adapting the height of the first positioning column to the thickness of the first hinge plate, the hinge stability of the first hinge plate can be stronger and it is not easy to deform.
[0014] Preferably, the second hinge seat includes a second positioning column provided on the outer end face of the first positioning plate or the second positioning plate, and a second circular limiting plate parallel to the plate body of the first positioning plate or the second positioning plate is provided on the outer end face of the second positioning column. The diameter of the second positioning column is smaller than the diameter of the second circular limiting plate. A second hinge plate is sleeved on the second positioning column, and a plurality of second hinge bases are provided on the end of the second hinge plate near the connecting disk. By sleeving the second hinge plate on the second positioning column and preventing the second hinge plate from falling off through the second circular limiting plate, the up-and-down swing of the second hinge plate can be realized, and the front-and-back swing of the connecting plate hinged on the second hinge base can be realized by the second hinge base provided on the outer end of the second hinge plate.
[0015] Preferably, a plurality of second hinge bases are arranged at intervals along the width direction of the second hinge plate, and each second hinge base is provided with a through hole passing through the upper and lower end faces. A circular limiting hole adapted to the diameter of the second positioning column is provided in the middle of the second hinge plate, and a sinking groove adapted to the second circular limiting plate is provided on the outer end face of the second hinge plate at the circular limiting hole. The height of the second positioning column is adapted to the thickness of the second hinge plate.
[0016] To sum up, the beneficial effects of the present utility model are as follows: The structure of the present utility model is simple and can provide additional flexibility in the longitudinal and transverse directions to adapt to more complex spatial displacement requirements. By providing a first short connection expansion tube and a second short connection expansion tube on the connecting pipe body and respectively connecting a left connection disk and a right connection disk, the left connection disk and the right connection disk located at the left and right ends can have a certain multi-directional displacement processing ability. The first positioning plate and the second positioning plate provided on the front and rear sides of the connecting pipe body are hinged to the connecting plates on the left connection disk and the right connection disk, which can effectively improve the overall stability of the pipe body while realizing the direction change of the two connection disks on the left and right of the device. By providing a first hinge seat and a second hinge seat at both ends of the positioning plate, it is convenient for the left connection disk to displace up and down at a relatively large distance relative to the right connection disk and for the left connection disk to displace up and down at a relatively small distance relative to the connecting pipe body. At the same time, it is convenient for the left connection disk to displace backward at a relatively large distance relative to the right connection disk and for the left connection disk to displace forward at a relatively small distance relative to the connecting pipe body. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 is a schematic structural diagram of the whole of the present utility model;
[0018] Figure 2 is a top view structural diagram of the present utility model;
[0019] Figure 3 is a schematic structural diagram of the first hinge plate of the present utility model;
[0020] Figure 4 is Figure 3 a cross-sectional structural diagram along A-A;
[0021] Figure 5 is a schematic structural diagram of the second hinge plate of the present utility model.
[0022] In the figure: 1, left connecting plate; 2, right connecting plate; 3, connecting plate; 4, connecting pipe body; 5, first short connecting expansion pipe; 6, second short connecting expansion pipe; 7, first positioning plate; 8, second positioning plate; 9, first hinge seat; 10, second hinge seat; 11, hinge notch; 12, first positioning column; 13, first circular limiting plate; 14, first hinge base; 15, circular limiting hole; 16, sunk groove; 17, second positioning column; 18, second circular limiting plate; 19, second hinge base; 20, first hinge plate; 21, second hinge plate. Specific embodiments
[0023] The following combines the drawings and embodiments to further describe in detail the specific embodiments of the present utility model. The following embodiments are used to illustrate the present utility model, but are not used to limit the scope of the present utility model.
[0024] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.
[0025] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.
[0026] The following is a description of the preferred embodiments of the present utility model in conjunction with the drawings.
[0027] As Figure 1 and Figure 2As shown in the figure, the utility model includes a left connection disk 1 and a right connection disk 2. On the inner end faces of the left connection disk 1 and the right connection disk 2, two connection plates 3 are respectively arranged. A connection pipe body 4 is arranged between the left connection disk 1 and the right connection disk 2. The left and right ends of the connection pipe body 4 are respectively provided with a first short connection expansion pipe 5 and a second short connection expansion pipe 6 which are connected to the left connection disk 1 and the right connection disk 2. In the design, the two connection plates 3 on the inner end faces of the left connection disk 1 and the right connection disk 2 are respectively vertically connected to the connection disk body, and the two connection plates 3 are located on the front and rear sides of the expansion pipe body. A plurality of hinge notches 11 are arranged at intervals in the width direction at the outer ends of the connection plates 3. The above-mentioned first short connection expansion pipe 5 and the second short connection expansion pipe 6 are both corrugated pipes, and the sizes of the two corrugated pipes are the same and are adapted to the diameter of the connection pipe body 4. At the same time, the front and rear ends of the first short connection expansion pipe 5 are respectively fixed on the rear end face of the right connection disk 2 and the right end face of the connection pipe body 4, and the front and rear ends of the second short connection expansion pipe 6 are respectively fixed on the left end face of the connection pipe body 4 and the rear end face of the left connection disk 1. By setting the first short connection expansion pipe 5 and the second short connection expansion pipe 6 as corrugated pipe structures, it can effectively facilitate the right connection disk 2 and the left connection disk 1 to adapt to the stress in different directions.
[0028] As Figure 1 and Figure 2 as well as Figure 3 and Figure 4As shown in the figure, in a preferred embodiment of the present utility model, on the front and rear sides of the above-mentioned connecting pipe body 4, a first positioning plate 7 and a second positioning plate 8 connected to the left and right connecting plates 3 are respectively provided. At the left ends of the first positioning plate 7 and the second positioning plate 8, a first hinge seat 9 and a second hinge seat 10 are respectively provided, while at the right ends of the first positioning plate 7 and the second positioning plate 8, a second hinge seat 10 and a first hinge seat 9 are respectively provided. In design, the first positioning plate 7 and the second positioning plate 8 are strip-shaped plates with a width size adapted to the width of the connecting plate 3, and the length of the strip-shaped plate body is adapted to the distance between the two connecting plates 3 on the left connecting disk 1 and the right connecting disk 2. In this way, by adapting the first positioning plate 7 and the second positioning plate 8 to the connecting plate 3, the stability during their hinging can be effectively improved, and the displacement processing ability in the composite direction can be made more flexible. During production, the above-mentioned first hinge seat 9 includes a first positioning post 12 provided on the outer end face of the first positioning plate 7 or the second positioning plate 8. On the outer end face of the first positioning post 12, a first circular limiting plate 13 parallel to the plate body of the first positioning plate 7 or the second positioning plate 8 is provided. Usually, the diameter of the first positioning post 12 is smaller than the diameter of the first circular limiting plate 13. A first hinge plate 20 is sleeved on the first positioning post 12, and on the outer end face of the first hinge plate 20 near the connecting disk end, a plurality of first hinge bases 14 are vertically fixed. In this way, by sleeving the first hinge plate 20 on the first positioning post 12 and preventing the first hinge plate 20 from falling off through the first circular limiting plate 13, the up and down swinging of the first hinge plate 20 can be realized, and the first hinge bases 14 provided on the outer end face of the first hinge plate 20 can cooperate with the hinge notch 11 at the outer end of the connecting plate 3, so as to realize the front and back swinging of the connecting plate 3 hinged on the first hinge bases 14.
[0029] As Figure 3 and Figure 4 shown, in another preferred embodiment of the present utility model, the above-mentioned plurality of first hinge bases 14 are arranged at intervals along the width direction of the first hinge plate 20, and through holes penetrating the upper and lower end faces are provided on each first hinge base 14. In design, a circular limiting hole 15 adapted to the diameter of the first positioning post 12 is provided in the middle of the first hinge plate 20, and a counterbore 16 adapted to the first circular limiting plate 13 is provided on the outer end face of the first hinge plate 20 at the circular limiting hole 15. The first positioning post 12 passes through the circular limiting hole 15 of the first hinge plate 20, and the height of the first positioning post 12 is adapted to the thickness of the first hinge plate 20. In this way, by adapting the height of the first positioning post 12 to the thickness of the first hinge plate 20, the stability of the first hinge plate 20 during hinging can be stronger and it is not easy to deform. Of course, during installation, the size and interval of the plurality of first hinge bases 14 are adapted to the hinge notch 11 provided at the outer end of the connecting plate 3, and a hinge shaft passing through the hinge notch 11 and the through hole of the first hinge base 14 in the vertical direction from the upper end face of the plate body is provided on the connecting plate 3.
[0030] As Figure 1 and Figure 2 as well as Figure 5 shown, in a specific embodiment of the present utility model, the above-mentioned second hinge seat 10 includes a second positioning column 17 provided on the outer end face of the first positioning plate 7 or the second positioning plate 8, and a second circular limiting plate 18 parallel to the plate body of the first positioning plate 7 or the second positioning plate 8 is provided on the outer end face of the second positioning column 17. The diameter of the second positioning column 17 is smaller than the diameter of the second circular limiting plate 18. At the same time, a second hinge plate 21 is sleeved on the second positioning column 17, and a plurality of second hinge bases 19 are provided at one end of the second hinge plate 21 close to the connecting plate. In this way, by sleeving the second hinge plate 21 on the second positioning column 17 and preventing the second hinge plate 21 from falling off through the second circular limiting plate 18, the up-and-down swing of the second hinge plate 21 can be realized, and the second hinge base 19 provided at the outer end of the second hinge plate 21 can realize the front-and-back swing of the connecting plate 3 hinged on the second hinge base 19. During manufacturing, a plurality of second hinge bases 19 are arranged at intervals along the width direction of the second hinge plate 21 at the outer end of the second hinge plate 21 and are located in the same plane as the second hinge plate 21, and a through hole passing through the upper and lower end faces is provided on each second hinge base 19. Similarly. A circular limiting hole 15 adapted to the diameter of the second positioning column 17 is provided in the middle of the second hinge plate 21, and a sink 16 adapted to the second circular limiting plate 18 is provided on the outer end face of the second hinge plate 21 at the circular limiting hole 15. The height of the second positioning column 17 is adapted to the thickness of the second hinge plate 21. In this way, by sleeving the second hinge plate 21 on the second positioning column 17 and preventing the second hinge plate 21 from falling off through the second circular limiting plate 18, the up-and-down swing of the second hinge plate 21 can be realized, and the second hinge base 19 provided on the outer end face of the second hinge plate 21 can cooperate with the hinge notch 11 at the outer end of the connecting plate 3, so as to realize the front-and-back swing of the connecting plate 3 hinged on the second hinge base 19. Of course, during installation, the sizes and intervals of the plurality of second hinge bases 19 are adapted to the hinge notch 11 provided at the outer end of the connecting plate 3, and a hinge shaft passing through the hinge notch 11 and the through hole of the second hinge base 19 in the vertical direction from the upper end face of the plate body is provided on the connecting plate 3.
[0031] In use, one end of the first positioning plate 7 and the second positioning plate 8 close to the left connecting plate 1 are respectively provided with a first hinge seat 9 and a second hinge seat 10 and are hinged to the connecting plate 3 through a hinge shaft, so as to realize the up-and-down swinging displacement and the forward displacement of the left connecting plate 1. One end of the first positioning plate 7 and the second positioning plate 8 close to the right connecting plate 2 are respectively provided with a second hinge seat 10 and a first hinge seat 9 and are hinged to the connecting plate 3 through a hinge shaft, so as to realize the up-and-down swinging displacement and the backward displacement of the left connecting plate 1. By the cooperation of the left connecting plate 1 and the right connecting plate 2, it is convenient for the left connecting plate 1 to have a large-distance up-and-down displacement relative to the right connecting plate 2 and a small-distance up-and-down displacement relative to the connecting pipe body 4. At the same time, it is convenient for the left connecting plate 1 to have a large-distance backward displacement relative to the right connecting plate 2 and a small-distance forward displacement relative to the connecting pipe body 4. The displacement transformation of the right connecting plate 2 is also based on the same principle, so as to realize that the device has a certain multi-directional displacement processing ability.
[0032] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A bushing short-circuit compensation device, comprising a left connecting plate (1) and a right connecting plate (2), wherein two connecting plates (3) are respectively arranged on the inner end surfaces of the left connecting plate (1) and the right connecting plate (2), and characterized in that: A connecting pipe body (4) is arranged between the left connecting plate (1) and the right connecting plate (2); a first short-circuit expansion pipe (5) and a second short-circuit expansion pipe (6) connected to the left connecting plate (1) and the right connecting plate (2) are arranged at the left and right ends of the connecting pipe body (4); a first positioning plate (7) and a second positioning plate (8) connected to the left and right connecting plates (3) are arranged at the front and rear sides of the connecting pipe body (4); a first hinge seat (9) and a second hinge seat (10) are arranged at the left ends of the first positioning plate (7) and the second positioning plate (8); and a second hinge seat (10) and a first hinge seat (9) are arranged at the right ends of the first positioning plate (7) and the second positioning plate (8).
2. The bushing short circuit compensation device according to claim 1, characterized in that: Two connecting plates (3) on the inner end surfaces of the left connecting plate (1) and the right connecting plate (2) are respectively vertically connected to the connecting plate body and are located at the front and rear sides of the expansion tube body, and the outer ends of the connecting plates (3) are provided with a plurality of hinge notches (11) at intervals along the width direction.
3. The bushing short circuit compensation device according to claim 1, characterized in that: The first short-circuit expansion tube (5) and the second short-circuit expansion tube (6) are both bellows and have the same size and are adapted to the diameter of the connecting tube body (4). The front and rear ends of the first short-circuit expansion tube (5) are respectively fixedly connected to the rear end surface of the right connecting plate (2) and the right end surface of the connecting tube body (4). The front and rear ends of the second short-circuit expansion tube (6) are respectively fixedly connected to the left end surface of the connecting tube body (4) and the rear end surface of the left connecting plate (1).
4. The bushing short circuit compensation device according to claim 1, characterized in that: The first positioning plate (7) and the second positioning plate (8) are strip plates whose width is adapted to the width of the connecting plate (3), and the length of the strip plate body is adapted to the spacing between the two connecting plates (3) on the left connecting plate (1) and the right connecting plate (2).
5. The bushing short circuit compensation device according to claim 1, characterized in that: The first hinge seat (9) comprises a first positioning column (12) arranged on the outer end surface of the first positioning plate (7) or the second positioning plate (8), and a first circular stop plate (13) parallel to the first positioning plate (7) or the second positioning plate (8) is arranged on the outer end surface of the first positioning column (12), the diameter of the first positioning column (12) is smaller than the diameter of the first circular stop plate (13), the first positioning column (12) is sleeved with a first hinge plate (20), and a plurality of first hinge bases (14) are arranged on the outer end surface of the first hinge plate (20) close to one end of the connecting plate.
6. The bushing short-circuit compensation device according to claim 5, characterized in that: The plurality of first hinge bases (14) are arranged at intervals along the width direction of the first hinge plate (20), and each first hinge base (14) is provided with a through hole passing through the upper and lower end surfaces, a circular limiting hole (15) adapted to the diameter of the first positioning column (12) is provided in the middle of the first hinge plate (20), and a sink groove (16) adapted to the first circular limiting plate (13) is provided on the outer end surface of the first hinge plate (20) at the circular limiting hole (15), and the height of the first positioning column (12) is adapted to the thickness of the first hinge plate (20).
7. The bushing short-circuit compensation device according to claim 1, characterized in that: The second hinge seat (10) comprises a second positioning column (17) arranged on the outer end surface of the first positioning plate (7) or the second positioning plate (8), and a second circular stop plate (18) parallel to the first positioning plate (7) or the second positioning plate (8) is arranged on the outer end surface of the second positioning column (17), the diameter of the second positioning column (17) is smaller than the diameter of the second circular stop plate (18), a second hinge plate (21) is sleeved on the second positioning column (17), and a plurality of second hinge bases (19) are arranged on one end of the second hinge plate (21) close to the connecting plate.
8. The bushing short circuit compensation device according to claim 7, characterized in that: The plurality of second hinge bases (19) are arranged at intervals along the width direction of the second hinge plate (21), and each second hinge base (19) is provided with a through hole passing through the upper and lower end surfaces, a circular limiting hole (15) adapted to the diameter of the second positioning column (17) is provided in the middle of the second hinge plate (21), and a sink groove (16) adapted to the second circular limiting plate (18) is provided on the outer end surface of the second hinge plate (21) at the circular limiting hole (15), and the height of the second positioning column (17) is adapted to the thickness of the second hinge plate (21).