Automatic die assembling and disassembling die for energy-saving prefabricated pipe gallery expansion joint

Abstract

The invention relates to the technical field of pipe gallery forming, in particular to an energy-saving type prefabricated pipe gallery expansion joint automatic die-filling and die-stripping die which comprises two symmetrical shells, inner plates are slidably connected into cavities of the two shells, clamping cavities are formed in the spaces between the shells and the inner plates, motors are installed on the sides, close to the shells, of the inner plates, and the clamping cavities are connected with the motors. An inner plate is driven by a driving structure to move, so that when the inner plate is in a shell, an eccentric block and an inclined block are driven by a motor to rotate, the inner plate can continuously vibrate to reduce gaps between concrete on the side wall of a pipe gallery, after a hub is formed and taken out, the inner plate is elastically supported through abutting of a first spring in a three-section telescopic pipe, and the inner plate is prevented from falling off. And then the two inner plates abut against each other through a driving structure, then through eccentric shaking of an eccentric block and an inclined block, the two inner plates rub against each other to clean away cement residues on the inner plates, and meanwhile the discharging effect of cement scraps can be promoted when the inner plates are polished.

Description

Technical Field

[0001] The present invention relates to the technical field of pipe gallery forming, in particular to an automatic moulding and demoulding mould for energy-saving prefabricated pipe gallery expansion joints. Background Art

[0002] In the traditional production of prefabricated pipe gallery expansion joints, steel mold components need to be manually carried and spliced, manually fixed, concrete poured and cured, and then the molds are manually disassembled, cleaned and recycled. However, this process has problems such as low efficiency, poor consistency in manual operation resulting in a high rework rate of finished products, poor mold versatility and large inventory, serious energy consumption and material waste, low degree of automation and disconnection from the industry's intelligent upgrade needs, prompting the research and development of energy-saving automatic mold loading and disassembly.

[0003] However, in the existing process of forming the tunnel, since the side walls of the tunnel mold are wrapped by the mold, it is necessary to continuously vibrate the vibrator from the upper end of the tunnel to reduce the gaps between the cements, which makes the vibrator less effective and leads to irrational use of energy. At the same time, after the tunnel is formed and taken out, the staff is required to grind the side walls of the mold to clean up the cement residue on the mold. Since the tunnel mold is large, this will make grinding the tunnel mold a long process, which greatly affects work efficiency and makes it impossible to reasonably use human resources. Summary of the Invention

[0004] The purpose of the invention is to provide an energy-saving prefabricated pipe gallery expansion joint automatic mold assembly and disassembly mold to solve the problems raised in the above background technology.

[0005] To achieve the above-mentioned object, the present invention provides the following technical solution: an automatic mold assembly and demolding mold for an energy-saving prefabricated pipe gallery expansion joint, comprising two symmetrical outer shells, inner plates being slidably connected to the cavities of the two outer shells, the space between the outer shells and the inner plates forming a clamping cavity, a motor being mounted on a side of the inner plate close to the outer shell, an eccentric block being fixedly connected to the output end of the motor, an inclined block being mounted on the eccentric block, an inclined top block adapted to the inclined block being fixedly connected to one side of the outer shell, an outer side wall of the inclined top block being fixedly connected to a limit shell, and the limit shell being capable of being sleeved on the outer side wall of the eccentric block; A plurality of three-section movable tubes are provided on one side of the inner plate close to the outer shell, and an axis frame is fixedly connected to the outer wall of each of the three-section movable tubes at a corresponding position on one side of the inner plate, and a rotating shaft is rotatably connected in the cavity of each axis frame, and a sliding column is fixedly connected to the side close to each other of two opposite rotating shafts, and a central tube is slidably connected between the two sliding columns; The interior of the three-section movable tube is provided with a breathing structure capable of inhaling and exhausting air in opposite directions of the two shells; A driving structure is installed on a side of the shell away from the inner plate, which can drive a rotating shaft installed on one side of the shell to rotate.

[0006] Preferably, the driving structure includes two connecting rods, which are symmetrically connected to the upper and lower sides of the inner wall of the inner plate, and each connecting rod is fixed to the rotating shaft at the corresponding position. The outer wall of each connecting rod is fixed with a gear, and a rack is engaged with one side of the gear, and the rack slides through the outer wall of the outer shell.

[0007] Preferably, a positioning plate is fixedly connected to the side of the rack away from the shell, two positioning columns are symmetrically slidably connected on both sides of the positioning plate, and the positioning columns are fixed to the outer wall of the shell, and a strong spring is also installed between the positioning plate and the outer wall of the shell, and the strong spring is sleeved on the outer wall of the rack.

[0008] Preferably, each positioning plate is fixed with a spring 2 on one side away from the rack, and the two springs 2 are commonly fixed with a connecting plate on one side away from the housing. A cylinder is provided on one side of the connecting plate, and the output end of the cylinder is fixed to the connecting plate.

[0009] Preferably, the lower ends of the two shells are commonly provided with a base plate, and the base plate is symmetrically provided with two groups of slide grooves, each group of the slide grooves is slidingly connected to the shell at the corresponding position, and the upper end of the base plate is symmetrically installed with two connecting seats, and the upper end of each connecting seat is fixedly connected to the cylinder at the corresponding position.

[0010] Preferably, the breathing structure includes several trachea, which are fixed to the side close to the inner plate, and each trachea is slidably connected to the inner wall of the three-section movable tube. The outer wall of the trachea is provided with a spring, and the two ends of the spring are respectively in contact with the bottom and top of the inner cavity of the three-section movable tube.

[0011] Preferably, a plurality of air cavities are opened at the upper end of the inner plate, and each air cavity is connected to the air pipe at the corresponding position, the upper notch of each air pipe is fixedly connected to an exhaust pipe, and the notch of the exhaust pipe is fixedly connected to a filter screen.

[0012] Preferably, an outer mold door is rotatably connected to the outer side wall of each shell, and each outer mold door can be screwed to another shell. An inner mold is provided on one side of the shell, and the inner mold can be inserted between two inner plates.

[0013] Compared with the prior art, the present invention has the following beneficial effects: The motor drives the inclined block and the inclined top block to slide against each other, so that the inner plate vibrates to reduce the gap between the cements, reduces the frequency of using the vibrating rod, and improves work efficiency. Later, when the formed pipe gallery is steam-cured, the cylinder pushes the connecting plate to move back and forth repeatedly in a small range, so that the three-section movable tube can perform telescopic movement to absorb steam into the inside of the three-section movable tube and then discharge it to increase the temperature inside the clamping cavity and conduct it to the side wall of the pipe gallery, solving the problem that the side wall of the pipe gallery is difficult to be cured by steam temperature. Finally, after the pipe gallery is formed and taken out, the cylinder is further pushed The dynamic connecting plate moves, and the two inner plates are pushed to conflict with each other through the driving structure. At this time, the motor is started again to drive the eccentric block to rotate, which will cause the oblique block and the eccentric block to form an eccentric structure, thereby driving the inner plate to vibrate up and down. The two inner plates vibrate up and down while conflicting with each other, which will cause the cement residue on the surface of the inner plate to be preliminarily polished and cleaned, reducing the workload of the staff in the subsequent process of fine polishing. While the inner plate shakes up and down, the three-section movable pipe will be extended and slid again, so that the exhaust pipe will inhale and exhale to the polishing position, which promotes the discharge of cement chips during polishing. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention will be further explained below in conjunction with the accompanying drawings and examples: Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a schematic diagram of the partial structure of the housing of the present invention; Figure 3 This is a schematic diagram of the internal structure of the inner plate after removing the outer shell of the present invention; Figure 4 For the present invention Figure 3 Enlarged view of point A in the middle; Figure 5 It is a structural schematic diagram of the eccentric block and the oblique block of the present invention; Figure 6 This is a schematic diagram of the internal structure of the housing after removing the inner plate of the present invention; Figure 7 Schematic diagram of the cross-sectional structure of the housing of the present invention; Figure 8 is a schematic cross-sectional structural diagram of the inner panel of the present invention; Figure 9 For the present invention Figure 7 Enlarged view of point B in the middle.

[0015] Description of reference numerals: 1. Outer shell; 2. Inner plate; 3. Clamping cavity; 4. Motor; 5. Eccentric block; 51. Oblique block; 6. Inclined top block; 7. Limiting shell; 8. Air pipe; 9. Spring 1; 10. Center tube; 11. Sliding column; 12. Three-section movable tube; 13. Rotating shaft; 14. Axle frame; 15. Connecting rod; 16. Gear; 17. Rack; 18. Power spring; 19. Positioning plate; 20. Positioning column; 21. Spring 2; 22. Connecting plate; 23. Cylinder; 24. Connecting seat; 25. Bottom plate; 26. Slide groove; 27. Inner mold; 28. Outer mold door; 29. ​​Air cavity; 30. Exhaust pipe; 31. Filter. DETAILED DESCRIPTION

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0017] See also Figures 1-9 The present invention provides a technical solution: an automatic mold assembly and demolding mold for an energy-saving prefabricated pipe gallery expansion joint, comprising two symmetrical outer shells 1, inner plates 2 being slidably connected to the cavities of the two outer shells 1, a clamping cavity 3 being formed between the outer shells 1 and the inner plates 2, a motor 4 being installed on the side of the inner plate 2 close to the outer shell 1, an eccentric block 5 being fixedly connected to the output end of the motor 4, an inclined block 51 being installed on the eccentric block 5, an inclined top block 6 being fixedly connected to one side of the outer shell 1, an outer side wall of the inclined top block 6 being fixedly connected to a limit shell 7, and the limit shell 7 being able to be sleeved on the outer side wall of the eccentric block 5; Several three-section movable tubes 12 are provided on the side of the inner plate 2 close to the outer shell 1. The outer wall of each three-section movable tube 12 is fixedly connected to the corresponding position of the side of the inner plate 2 with an axis frame 14. A rotating shaft 13 is rotatably connected in the cavity of each axis frame 14. A sliding post 11 is fixedly connected to the side of two opposing rotating shafts 13 close to each other. A central tube 10 is slidably connected between the two sliding posts 11. The interior of the three-section movable tube 12 is provided with a breathing structure, which can inhale and exhaust air in opposite directions of the two shells 1; A driving structure is installed on a side of the outer shell 1 away from the inner plate 2 , which can drive a rotating shaft 13 installed on one side of the outer shell 1 to rotate.

[0018] Specifically, refer to Figure 3 、 Figure 5 as well as Figure 6, wherein the inclined block 51 and the inclined top block 6 are both equipped with arc edges that conflict with each other. When the motor 4 drives the eccentric block 5 to rotate, if the inclined block 51 and the inclined top block 6 conflict with each other, the eccentric block 5 will conflict with the arc edge of the inclined top block 6 during the process of the eccentric block 5 driving the inclined block 51 to rotate, so that the eccentric block 5 is pushed to the side away from the outer shell 1, and the inner plate 2 will be pushed accordingly. Thereafter, the inner plate 2 is reset by the driving structure, so that the inner plate 2 produces repeated lateral vibrations to vibrate the side wall of the pipe gallery when pouring cement. At the same time, the limiting shell 7 limits the eccentric block 5 and the inclined top block 6, so that the gap between the unformed cement on the side wall of the pipe gallery is reduced by vibration, thereby improving work efficiency and reducing the use of vibrating rods; Then, when the inner plate 2 is separated from the cavity of the outer shell 1 and the two inner plates 2 are in conflict with each other, the motor 4 drives the eccentric block 5 to rotate. Since the inclined block 51 is a single counterweight, the center of gravity of the inclined block 51 is unstable, so that the inner plate 2 is driven to swing up and down during the rotation of the eccentric block 5. At the same time, the three-section movable tube 12 will continue to shrink. When the two inner plates 2 are swinging up and down, the driving structure makes them conflict with each other, which will cause the two inner plates 2 to rub against each other, thereby initially rubbing off the cement residue on the surface of the inner plate 2, making it convenient for workers to subsequently fine-grind the surface of the inner plate 2 to remove cement chips.

[0019] In this embodiment, the driving structure includes two connecting rods 15, which are symmetrically connected to the upper and lower sides of the inner wall of the inner plate 2, and each connecting rod 15 is fixed to the rotating shaft 13 at the corresponding position. The outer wall of each connecting rod 15 is fixed with a gear 16, and a rack 17 is engaged with one side of the gear 16, and the rack 17 slides through the outer wall of the outer shell 1.

[0020] In this embodiment, a positioning plate 19 is fixedly connected to the side of the rack 17 away from the shell 1, and two positioning columns 20 are symmetrically slidably connected on both sides of the positioning plate 19, and the positioning columns 20 are fixed to the outer wall of the shell 1. A strong spring 18 is also installed between the positioning plate 19 and the outer wall of the shell 1, and the strong spring 18 is sleeved on the outer wall of the rack 17.

[0021] In this embodiment, each positioning plate 19 is fixedly connected to a spring 21 on the side away from the rack 17, and the two springs 21 are commonly fixedly connected to a connecting plate 22 on the side away from the housing 1. A cylinder 23 is provided on one side of the connecting plate 22, and the output end of the cylinder 23 is fixedly connected to the connecting plate 22.

[0022] In this embodiment, a base plate 25 is commonly provided at the lower ends of the two shells 1, and two groups of slide grooves 26 are symmetrically opened on the base plate 25. Each group of slide grooves 26 is slidingly connected to the shell 1 at the corresponding position. Two connecting seats 24 are symmetrically installed on the upper end of the base plate 25, and the upper end of each connecting seat 24 is fixedly connected to the cylinder 23 at the corresponding position.

[0023] In this embodiment, the breathing structure includes several trachea 8, which are fixed to the side close to the inner plate 2, and each trachea 8 is slidably connected to the inner wall of the three-section movable tube 12. The outer wall of the trachea 8 is provided with a spring 9, and the two ends of the spring 9 respectively contact the bottom and top of the inner cavity of the three-section movable tube 12.

[0024] In this embodiment, a plurality of air cavities 29 are provided at the upper end of the inner plate 2, and each air cavity 29 is connected to the air pipe 8 at the corresponding position. An exhaust pipe 30 is fixedly connected to the upper notch of each air pipe 8, and a filter screen 31 is fixedly connected to the notch of the exhaust pipe 30.

[0025] In this embodiment, an outer mold door 28 is rotatably connected to the outer wall of each shell 1, and each outer mold door 28 can be screwed to another shell 1. An inner mold 27 is provided on one side of the shell 1, and the inner mold 27 can be inserted between the two inner plates 2.

[0026] Specifically, refer to Figure 3 as well as Figure 6 , each adjacent sliding post 11 on the left and right sides of the limit shell 7 is a cross structure, so that when the rotating shaft 13 is rotated, the sliding post 11 can push the inner plate 2 more stably; When the cylinder 23 pushes the connecting plate 22 to slide in the direction of the housing 1, it will first push the two housings 1 closer to each other until they move to the maximum distance that the housing 1 can slide in the slide groove 26. After that, the connecting plate 22 moves further in the direction of the housing 1 to push the rack 17 to slide. At the same time, the strong spring 18 begins to compress. During the sliding process of the rack 17, the two gears 16 will be driven to rotate. Then the gear 16 will push the connecting rod 15 and the corresponding position of the rotating shaft 13 to rotate, thereby causing the sliding column 11 to rotate. During the rotation of the sliding column 11, the rotating shaft 13 installed on the three-section movable tube 12 at the corresponding position will also rotate accordingly, while driving the three-section movable tube 12 to extend and retract, and then During the rotation of the sliding column 11, it will first slide inside the central tube 10, so that when the rack 17 is slightly pushed by the connecting plate 22 to drive the gear 16 to rotate, the inner plate 2 will not change its position, but the three-section movable tube 12 will still produce a certain telescopic movement. While the three-section movable tube 12 is telescopic, it will draw air to the outside through the trachea 8, the air cavity 29 and the exhaust pipe 30 and then exhale it. This makes it possible to inhale hot steam into the interior of the three-section movable tube 12 through the breathing structure during the telescopic process of the three-section movable tube 12, thereby increasing the temperature of the clamping cavity 3 area to maintain the side wall of the pipe gallery, thereby improving the maintenance effect of the side wall of the pipe gallery. When the connecting plate 22 is further pushed, the sliding column 11 slides to the end, and the rotating shaft 13 on the three-section movable tube 12 will rotate further, thereby pushing the three-section movable tube 12 to further expand and contract, and pushing the inner plate 2 to move in the direction away from the outer shell 1, finally making the two inner plates 2 fit together. At the same time, the connection between the inner plate 2 and the outer shell 1 is a plurality of mutually staggered sliding columns 11, and the inner plate 2 is supported in the middle position by the elastic restoring force released by the springs 9 inside the three-section movable tube 12. The support of the inner plate 2 at this time is an elastic support, which can float up and down when subjected to external force. At this time, when the motor 4 drives the eccentric block 5 to rotate, the instability of the rotation of the eccentric block 5 and the inclined block 51 will cause the inner plate 2 to continuously shake up and down, thereby realizing the mutual grinding between the two inner plates 2, pre-treating the cement residue on the surface of the inner plate 2, and facilitating the subsequent grinding by the workers; During the grinding process, the up and down movement of the inner plate 2 will again cause the three sections of the movable tube 12 to perform telescopic movement. Figure 8 and Figure 9 The slot of the exhaust pipe 30 is positioned obliquely downward toward the relative inner plate 2, so that during the telescopic movement of the three-section movable tube 12, air will be continuously sucked in and blown out toward the grinding position of the two inner plates 2, thereby promoting the falling of cement chips during grinding. At the same time, the filter 31 is used to prevent cement chips from being sucked into the exhaust pipe 30 during the suction process.

[0027] Working principle: The outer shell 1 is pushed to the end by the cylinder 23, and then the worker places the steel frame between the two outer shells 1. Then the worker rotates the two outer mold doors 28 and screws them with the adjacent outer shells 1. Then the inner mold 27 is inserted between the two outer shells 1 and fixed by screwing, thereby completing the mold construction of the pipe gallery. Then the worker pours cement from the upper end between the two outer shells 1. During the cement pouring process, the motor 4 will drive the eccentric block 5 to rotate rapidly, causing the inclined block 51 and the inclined top block 6 to slide against each other, thereby allowing the inner plate 2 to vibrate. During the cement pouring process, the side wall of the pipe gallery can vibrate quickly to reduce the gap between the cement, reduce the frequency of using the vibrating rod, improve work efficiency, and thus reduce the use of manpower and energy. Later, when the formed pipe gallery is steam-cured, the cylinder 23 is used to push the connecting plate 22 to move back and forth in a small range, so that the sliding column 11 drives the three-section movable pipe 12 to extend and retract while not driving the inner plate 2 to move and cause damage to the pipe gallery. At the same time as the movement, the breathing structure will inhale the steam into the three-section movable tube 12 and then discharge it, thereby increasing the temperature inside the clamping cavity 3 to conduct it to the side wall of the pipe gallery, solving the problem that the side wall of the pipe gallery is difficult to be maintained by the steam temperature, so that the side wall of the pipe gallery can be heated without discharging a large amount of hot steam, reducing the use of energy. Finally, after the pipe gallery is formed and taken out, the cylinder 23 further pushes the connecting plate 22 to move, so that the rack 17 drives the gear 16 to rotate, and the sliding column 11 is driven to rotate through the rotating shaft 13 to push the two inner plates 2 to the same position. When the inner plate 2 is shaken up and down, the three-section movable tube 12 will be extended and slid again, so that the exhaust pipe 30 will inhale and exhale to the grinding position, which promotes the discharge of cement chips during grinding.

[0028] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. An automatic mold assembly and demolding mold for an energy-saving prefabricated pipe gallery expansion joint, comprising two symmetrical outer shells (1), wherein inner plates (2) are slidably connected to the cavities of the two outer shells (1), and characterized in that: The space between the outer shell (1) and the inner plate (2) forms a clamping cavity (3); a motor (4) is installed on the side of the inner plate (2) close to the outer shell (1); an eccentric block (5) is fixedly connected to the output end of the motor (4); an inclined block (51) is installed on the eccentric block (5); a slanted top block (6) adapted to the inclined block (51) is fixedly connected to one side of the outer shell (1); an outer side wall of the inclined top block (6) is fixedly connected to a limiting shell (7), and the limiting shell (7) can be sleeved on the outer side wall of the eccentric block (5); A plurality of three-section movable tubes (12) are provided on a side of the inner plate (2) close to the outer shell (1), and an axis frame (14) is fixedly connected to the corresponding position of the outer wall of each of the three-section movable tubes (12) and one side of the inner plate (2), and a rotating shaft (13) is rotatably connected in the cavity of each of the axis frames (14), and a sliding column (11) is fixedly connected to the side of two opposite rotating shafts (13) close to each other, and a central tube (10) is slidably connected between the two sliding columns (11); The three-section movable tube (12) is provided with a breathing structure inside, capable of inhaling and exhausting air in opposite directions of the two shells (1); A driving structure is installed on the side of the outer shell (1) away from the inner plate (2), capable of driving a rotating shaft (13) installed on one side of the outer shell (1) to rotate.

2. The automatic mold assembly and demoulding mold for an energy-saving prefabricated pipe gallery expansion joint according to claim 1 is characterized in that: The driving structure includes two connecting rods (15), the two connecting rods (15) are symmetrically connected to the upper and lower sides of the inner wall of the inner plate (2), and each connecting rod (15) is fixed to the rotating shaft (13) at the corresponding position. The outer wall of each connecting rod (15) is fixed with a gear (16), one side of the gear (16) is engaged with a rack (17), and the rack (17) slides through the outer wall of the outer shell (1).

3. The automatic mold assembly and demoulding mold for an energy-saving prefabricated pipe gallery expansion joint according to claim 2 is characterized in that: A positioning plate (19) is fixedly connected to the side of the rack (17) away from the housing (1), and two positioning columns (20) are symmetrically slidably connected to the two sides of the positioning plate (19), and the positioning columns (20) are fixedly connected to the outer wall of the housing (1). A strong spring (18) is also installed between the positioning plate (19) and the outer wall of the housing (1), and the strong spring (18) is sleeved on the outer wall of the rack (17).

4. The automatic mold assembly and demoulding mold for an energy-saving prefabricated pipe gallery expansion joint according to claim 3 is characterized by: A spring 2 (21) is fixedly connected to one side of each positioning plate (19) away from the rack (17), and a connecting plate (22) is fixedly connected to the two sides of the springs 2 (21) away from the housing (1). A cylinder (23) is provided on one side of the connecting plate (22), and an output end of the cylinder (23) is fixedly connected to the connecting plate (22).

5. The automatic mold assembly and demoulding mold for an energy-saving prefabricated pipe gallery expansion joint according to claim 4 is characterized in that: The lower ends of the two shells (1) are commonly provided with a bottom plate (25), and the bottom plate (25) is symmetrically provided with two groups of slide grooves (26), and each group of the slide grooves (26) is slidably connected to the shell (1) at a corresponding position. The upper end of the bottom plate (25) is symmetrically provided with two connecting seats (24), and the upper end of each connecting seat (24) is fixedly connected to the cylinder (23) at a corresponding position.

6. The automatic mold assembly and demoulding mold for an energy-saving prefabricated pipe gallery expansion joint according to claim 1 is characterized in that: The breathing structure includes a plurality of trachea (8), wherein the trachea (8) is fixedly connected to the side close to the inner plate (2), and each trachea (8) is slidably connected to the inner wall of the three-section movable tube (12), and the outer wall of the trachea (8) is provided with a spring (9), and the two ends of the spring (9) respectively contact the inner cavity bottom and the inner cavity top of the three-section movable tube (12).

7. The automatic mold assembly and demoulding mold for an energy-saving prefabricated pipe gallery expansion joint according to claim 6 is characterized in that: A plurality of air cavities (29) are provided at the upper end of the inner plate (2), and each air cavity (29) is communicated with an air pipe (8) at a corresponding position. An exhaust pipe (30) is fixedly connected to the upper notch of each air pipe (8), and a filter screen (31) is fixedly connected to the notch of the exhaust pipe (30).

8. The automatic mold assembly and disassembly mold for an energy-saving prefabricated pipe gallery expansion joint according to claim 1 is characterized by: An outer mold door (28) is rotatably connected to the outer side wall of each shell (1), and each outer mold door (28) can be screwed to another shell (1). An inner mold (27) is provided on one side of the shell (1), and the inner mold (27) can be inserted between the two inner plates (2).

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