Flaring device for plastic pipe production

Abstract

The utility model relates to the technical field of plastic pipe production, in particular to a flaring device for plastic pipe production, which can position the center of a plastic pipe, so that the plastic pipe and a flaring die are kept coaxial, and the flaring quality of the plastic pipe is improved. Comprising a bottom plate, a first sliding block, a vertical plate, an air cylinder, a flaring die, a clamping device, a power mechanism and a positioning device, the power mechanism is installed at the top end of the bottom plate, the first sliding block is connected with the power mechanism in a matched mode, the vertical plate is installed at the top end of the first sliding block, the air cylinder is installed at the left end of the vertical plate, and the output end of the air cylinder penetrates through the vertical plate to be connected with the flaring die; the clamping device is connected with the power mechanism in a matched mode, and the positioning device is installed on the right rear side of the top end of the bottom plate and corresponds to the clamping device in position.

Description

Technical Field

[0001] The utility model relates to the technical field of plastic pipe production, in particular to a expanding device for plastic pipe production. Background Art

[0002] As an important component of chemical building materials, plastic pipes are widely accepted by users for their superior performance, hygiene, environmental protection, low consumption and other advantages. There are mainly UPVC drainage pipes, UPVC water supply pipes, aluminum-plastic composite pipes, polyethylene (PE) water supply pipes, polypropylene PPR hot water pipes. The expansion device in the production of plastic pipes is a special equipment used to form an enlarged and neatly edged mouth at the end of the plastic pipe to facilitate connection with other pipe fittings (such as valves, joints, etc.). The expansion not only improves the sealing of the connection, but also enhances the physical strength of the connection.

[0003] The process of expanding a plastic pipe is usually to fix the pipe by a clamping device, then use a heating device to heat the position of the pipe to be expanded, and then use a expanding mold to expand the pipe.

[0004] However, when expanding the plastic pipe, it is impossible to position the plastic pipe to keep it coaxial with the expanding device. Without positioning, a certain offset may occur between the plastic pipe and the expanding device, and the coaxiality may be reduced, which may have a certain impact on the processed shape, reduce the quality of the plastic pipe expansion, and have certain limitations. Utility Model Content

[0005] In order to solve the above technical problems, the utility model provides a expanding device for plastic pipe production, which can locate the center of the plastic pipe by setting this equipment, so that the plastic pipe and the expanding mold maintain coaxiality, thereby improving the expanding quality of the plastic pipe.

[0006] The utility model discloses a flaring device for producing plastic pipes, comprising a bottom plate, a first slider, a vertical plate, a cylinder, a flaring die, a clamping device, a power mechanism and a positioning device, wherein the power mechanism is mounted on the top of the bottom plate, the first slider is cooperatively connected with the power mechanism, the vertical plate is mounted on the top of the first slider, the cylinder is mounted on the left end of the vertical plate, the cylinder output end passes through the vertical plate and is connected with the flaring die, the clamping device is cooperatively connected with the power mechanism, the positioning device is mounted on the right rear side of the top of the bottom plate, and the positioning device corresponds to the position of the clamping device.

[0007] Preferably, the clamping device comprises a U-shaped frame, two groups of first electric push rods, four groups of first telescopic tubes, four groups of first telescopic rods, four groups of springs, two groups of arc-shaped clamps, a second slider, a first motor and a lifting device, the second slider is connected in cooperation with the power mechanism, the first motor is installed at the top of the second slider, the U-shaped frame is installed at the output end of the first motor, the two groups of first electric push rods are respectively installed at the front end and the rear end of the U-shaped frame, the output ends of the two groups of first electric push rods respectively pass through the front end and the rear end of the U-shaped frame and are connected with the two groups of arc-shaped clamps, the four groups of first telescopic tubes are respectively installed at the upper and lower parts of the front and rear sides of the U-shaped frame, the four groups of first telescopic rods are respectively slidably connected with the four groups of first telescopic tubes, the inner ends of the four groups of first telescopic rods are respectively connected with the outer ends of the two groups of arc-shaped clamps, the four groups of springs are respectively sleeved on the four groups of first telescopic rods, one end of the four groups of springs is connected to the four groups of first telescopic rods, and the other ends of the four groups of springs are connected to the four groups of first telescopic tubes, and the lifting device is installed at the bottom inside the U-shaped frame.

[0008] Preferably, the power mechanism includes a bidirectional screw, two groups of fixed seats, a second motor and a guide rail, the two groups of fixed seats are symmetrically installed on the top of the base plate, the second motor is installed on the right end of the right fixed seat, the bidirectional screw is rotatably installed between the two groups of fixed seats, the output end of the second motor passes through the right fixed seat and is connected to the right end of the bidirectional screw, the guide rail is installed on the top of the base plate, the first slider and the second slider are both connected and provided with threaded holes in the middle part, the first slider and the second slider are both threadedly connected to the bidirectional screw, and the bottom ends of the first slider and the second slider are both slidably connected to the guide rail.

[0009] Preferably, the positioning device includes a three-jaw chuck, a base, three groups of screws, three groups of threaded sleeves, three groups of splints and a transmission device. The three-jaw chuck is installed on the base, and the base is installed on the right rear side of the top of the bottom plate. The three-jaw chuck corresponds to the position of the U-shaped frame, and the three-jaw chuck is consistent with the center position of the expansion mold. The middle part of the three-jaw chuck is connected with a through hole, and the front end of the three-jaw chuck is evenly provided with three groups of slide grooves. The three groups of screws are respectively rotatably installed inside the three groups of slide grooves. The transmission device is installed at the rear end of the three-jaw chuck, and the transmission device is matched with the inner ends of the three groups of slide grooves. The three groups of threaded sleeves are respectively threadedly connected to the three groups of screws, and the three groups of splints are respectively installed at the front ends of the three groups of threaded sleeves. The three groups of splints are located on the front side of the three-jaw chuck, and the three groups of threaded sleeves are slidably connected to the three groups of slide grooves.

[0010] Preferably, the transmission device includes a transmission box, a rotating shaft, a first gear, a gear shaft and three groups of second gears. The transmission box is installed in the middle of the rear end of the three-jaw chuck, the transmission box is connected to the through hole in the middle of the three-jaw chuck, the rotating shaft is rotatably installed on the top of the transmission box, the bottom of the rotating shaft is located inside the transmission box, the first gear is installed at the bottom of the rotating shaft, the first gear is meshed with the rear end of the gear shaft, the gear shaft is rotatably installed inside the transmission box, the three groups of second gears are respectively installed at the inner ends of the three groups of screws, and the three groups of second gears are all meshed with the front end of the gear shaft.

[0011] Preferably, the lifting device includes a second electric push rod, a movable plate, three groups of rollers and an auxiliary device. The second electric push rod is installed in the middle of the bottom end of the U-shaped frame, the movable plate is installed at the output end of the second electric push rod, three groups of mounting grooves are provided at the top of the movable plate, the three groups of rollers are rotatably installed in the three groups of mounting grooves at the top of the movable plate, and the auxiliary device is installed at the bottom end of the U-shaped frame, and the auxiliary device is cooperatively connected with the movable plate.

[0012] Preferably, the auxiliary device includes two groups of second telescopic tubes and two groups of second telescopic rods, the two groups of second telescopic tubes are respectively installed on the front and rear sides of the bottom end of the U-shaped frame, the two groups of second telescopic rods are respectively installed on the front and rear sides of the bottom end of the movable plate, and the two groups of second telescopic rods are respectively slidably connected to the two groups of second telescopic tubes.

[0013] Preferably, the inner ends of the two groups of arc-shaped clamping plates, the inner ends of the three groups of clamping plates and the surfaces of the three groups of rollers are all provided with rubber layers.

[0014] Compared with the prior art, the beneficial effects of the utility model are as follows: the clamping device is started and rotated backward 90 degrees so that the position of the clamping device corresponds to that of the positioning device, and then the pipe is placed on the clamping device so that the pipe contacts the positioning device, and then the positioning device positions the pipe, and then the clamping device fixes the pipe, and then the clamping device is opened to reset the clamping device, and then the power mechanism is opened, and the power mechanism drives the clamping device and the first slider to move inward at the same time, and the first slider drives the vertical plate to move inward. When the vertical plate and the pipe on the clamping device move to the specified position, the power mechanism is closed, and the heating device heats and softens the position of the pipe to be expanded, and then the cylinder is opened, and the cylinder drives the expanding mold to move to the right, thereby expanding the pipe. By setting this device, the center positioning of the plastic pipe can be achieved, so that the plastic pipe and the expanding mold remain coaxial, thereby improving the expanding quality of the plastic pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the utility model;

[0016] Figure 2 yes Figure 1 A right view structural diagram of ;

[0017] Figure 3 yes Figure 1 A vertically enlarged structural diagram of the middle three-jaw chuck;

[0018] Figure 4 yes Figure 1 A schematic diagram of the enlarged longitudinal section of the middle three-jaw chuck;

[0019] Markings in the accompanying drawings: 1. bottom plate; 2. first slider; 3. vertical plate; 4. cylinder; 5. expansion mold; 6. U-shaped frame; 7. first electric push rod; 8. first telescopic tube; 9. first telescopic rod; 10. spring; 11. arc-shaped clamping plate; 12. second slider; 13. first motor; 14. bidirectional screw; 15. fixed seat; 16. second motor; 17. three-jaw chuck; 18. base; 19. slide groove; 20. screw; 21. screw sleeve; 22. clamping plate; 23. transmission box; 24. rotating shaft; 25. first gear; 26. gear shaft; 27. second gear; 28. second electric push rod; 29. ​​moving plate; 30. roller; 31. second telescopic tube; 32. second telescopic rod; 33. guide rail. DETAILED DESCRIPTION

[0020] The following is a further detailed description of the specific implementation of the present invention in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0021] like Figures 1 to 4 As shown, the utility model is a flaring device for plastic pipe production, comprising a bottom plate 1, a first slider 2, a vertical plate 3, a cylinder 4, a flaring die 5, a clamping device, a power mechanism and a positioning device, the power mechanism is mounted on the top of the bottom plate 1, the first slider 2 is connected with the power mechanism, the vertical plate 3 is mounted on the top of the first slider 2, the cylinder 4 is mounted on the left end of the vertical plate 3, the output end of the cylinder 4 passes through the vertical plate 3 and is connected with the flaring die 5, the clamping device is connected with the power mechanism, the positioning device is mounted on the right rear side of the top of the bottom plate 1, and the positioning device corresponds to the clamping device;

[0022] Start the clamping device and rotate it backward 90 degrees so that the position of the clamping device corresponds to that of the positioning device. Then place the pipe on the clamping device so that the pipe contacts the positioning device. Then the positioning device positions the pipe. Then the clamping device fixes the pipe. Then the clamping device is opened to reset the clamping device. Then the power mechanism is turned on. The power mechanism drives the clamping device and the first slider 2 to move inward at the same time. The first slider 2 drives the vertical plate 3 to move inward. When the vertical plate 3 and the pipe on the clamping device move to the specified position, the power mechanism is turned off so that the heating device heats and softens the position of the pipe to be expanded. Then the cylinder 4 is turned on. The cylinder 4 drives the expanding mold 5 to move rightward, thereby expanding the pipe. By setting this device, the center of the plastic pipe can be positioned, so that the plastic pipe and the expanding mold 5 remain coaxial, thereby improving the expanding quality of the plastic pipe.

[0023] As a preferred embodiment of the above embodiment, the clamping device includes a U-shaped frame 6, two groups of first electric push rods 7, four groups of first telescopic tubes 8, four groups of first telescopic rods 9, four groups of springs 10, two groups of arc-shaped clamping plates 11, a second slider 12, a first motor 13 and a lifting device, the second slider 12 is connected with the power mechanism, the first motor 13 is installed at the top of the second slider 12, the U-shaped frame 6 is installed at the output end of the first motor 13, the two groups of first electric push rods 7 are respectively installed at the front end and the rear end of the U-shaped frame 6, and the output ends of the two groups of first electric push rods 7 are respectively passed through the U The front and rear ends of the frame 6 are connected to the two groups of arc-shaped clamping plates 11, and the four groups of first telescopic tubes 8 are respectively installed on the upper and lower parts of the front and rear sides of the U-shaped frame 6, and the four groups of first telescopic rods 9 are respectively slidably connected to the four groups of first telescopic tubes 8, and the inner ends of the four groups of first telescopic rods 9 are respectively connected to the outer ends of the two groups of arc-shaped clamping plates 11, and the four groups of springs 10 are respectively sleeved on the four groups of first telescopic rods 9, one end of the four groups of springs 10 is connected to the four groups of first telescopic rods 9, and the other end of the four groups of springs 10 is connected to the four groups of first telescopic tubes 8, and the lifting device is installed at the bottom of the U-shaped frame 6;

[0024] By arranging the U-shaped frame 6, the first electric push rod 7, the first telescopic tube 8, the first telescopic rod 9, the spring 10, the arc-shaped clamping plate 11, the second slider 12, the first motor 13 and the lifting device, the first motor 13 is turned on, the first motor 13 drives the U-shaped frame 6 to rotate backward 90 degrees, the plastic pipe is placed on the lifting device, and then the plastic pipe is pushed to correspond to the position of the positioning device, and then the lifting device is turned on, the lifting device drives the plastic pipe to move to a specified height, and then the pipe is contacted with the positioning device, and the positioning device positions the pipe, and then the two groups of first electric push rods 7 are turned on, the two groups of first electric push rods 7 drive the two groups of arc-shaped clamping plates 11 to clamp and fix the pipe, and then the first motor 13 is turned on, the first motor 13 drives the U-shaped frame 6 to reset, so as to clamp and fix the pipe.

[0025] As a preferred embodiment of the above, the power mechanism includes a bidirectional screw 14, two sets of fixed seats 15, a second motor 16 and a guide rail 33. The two sets of fixed seats 15 are symmetrically installed at the top of the base plate 1, the second motor 16 is installed at the right end of the right fixed seat 15, the bidirectional screw 14 is rotatably installed between the two sets of fixed seats 15, the output end of the second motor 16 passes through the right fixed seat 15 and is connected to the right end of the bidirectional screw 14, the guide rail 33 is installed at the top of the base plate 1, the first slider 2 and the second slider 12 are both connected and provided with threaded holes in the middle, the first slider 2 and the second slider 12 are both threadedly connected to the bidirectional screw 14, and the bottom ends of the first slider 2 and the second slider 12 are both slidably connected to the guide rail 33;

[0026] By setting the bidirectional screw 14, the fixing seat 15, the second motor 16 and the guide rail 33, by turning on the second motor 16, the second motor 16 drives the bidirectional screw 14 to rotate, and the bidirectional screw 14 is threadedly connected with the first slider 2 and the second slider 12. The first slider 2 drives the vertical plate 3 to move inward, and the second slider 12 drives the U-shaped frame 6 to move inward, which plays a role in driving the vertical plate 3 and the U-shaped frame 6 to move inward synchronously.

[0027] As a preferred embodiment of the above, the positioning device includes a three-jaw chuck 17, a base 18, three groups of screws 20, three groups of screw sleeves 21, three groups of clamping plates 22 and a transmission device. The three-jaw chuck 17 is installed on the base 18, and the base 18 is installed on the right rear side of the top of the bottom plate 1. The three-jaw chuck 17 corresponds to the position of the U-shaped frame 6. The three-jaw chuck 17 is consistent with the center position of the expansion mold 5. The middle part of the three-jaw chuck 17 is connected with a perforation. The front end of the three-jaw chuck 17 is evenly provided with three groups of slide grooves 19. The three groups of screws 20 are rotatably installed inside the three groups of slide grooves 19, and the transmission device is installed at the rear end of the three-jaw chuck 17. The transmission device is connected with the inner end of the three groups of slide grooves 19. The three groups of screw sleeves 21 are threadedly connected with the three groups of screws 20, and the three groups of clamping plates 22 are respectively installed at the front ends of the three groups of screw sleeves 21. The three groups of clamping plates 22 are located at the front side of the three-jaw chuck 17, and the three groups of screw sleeves 21 are slidably connected with the three groups of slide grooves 19.

[0028] By setting a three-jaw chuck 17, a base 18, a slide groove 19, a screw 20, a screw sleeve 21, a clamping plate 22 and a transmission device, when the pipe contacts the front end of the three-jaw chuck 17, the three groups of screws 20 are driven to rotate through the transmission device, and the three groups of screws 20 are threadedly connected with the three groups of screw sleeves 21. The three groups of screw sleeves 21 drive the three groups of clamping plates 22 to move inward synchronously, and the three groups of clamping plates 22 perform center positioning on the pipe, thereby playing a role in center positioning of the pipe.

[0029] As a preferred embodiment of the above, the transmission device includes a transmission box 23, a rotating shaft 24, a first gear 25, a gear shaft 26 and three groups of second gears 27. The transmission box 23 is installed in the middle of the rear end of the three-jaw chuck 17, and the transmission box 23 is connected to the through hole in the middle of the three-jaw chuck 17. The rotating shaft 24 is rotatably installed on the top of the transmission box 23, and the bottom of the rotating shaft 24 is located inside the transmission box 23. The first gear 25 is installed at the bottom end of the rotating shaft 24, and the first gear 25 is meshed with the rear end of the gear shaft 26. The gear shaft 26 is rotatably installed inside the transmission box 23. The three groups of second gears 27 are respectively installed at the inner ends of the three groups of screws 20, and the three groups of second gears 27 are all meshed with the front end of the gear shaft 26.

[0030] By setting up a transmission box 23, a rotating shaft 24, a first gear 25, a gear shaft 26 and a second gear 27, the first gear 25 is rotated by the rotating shaft 24, the first gear 25 is meshed with the gear shaft 26, the gear shaft 26 is meshed with three groups of second gears 27, the three groups of second gears 27 drive the three groups of screw rods 20 to rotate, and the three groups of screw rods 20 are threadedly connected with the three groups of screw sleeves 21, so as to provide power to the three groups of screw rods 20.

[0031] As a preferred embodiment of the above, the lifting device includes a second electric push rod 28, a moving plate 29, three groups of rollers 30 and an auxiliary device. The second electric push rod 28 is installed in the middle of the bottom end of the U-shaped frame 6, the moving plate 29 is installed at the output end of the second electric push rod 28, and three groups of mounting grooves are arranged at the top of the moving plate 29. The three groups of rollers 30 are rotatably installed in the three groups of mounting grooves at the top of the moving plate 29. The auxiliary device is installed at the bottom end of the U-shaped frame 6, and the auxiliary device is connected with the moving plate 29.

[0032] By setting the second electric push rod 28, the movable plate 29, the rollers 30 and the auxiliary device, the pipe is placed on the three groups of rollers 30, and then the second electric push rod 28 is turned on. The second electric push rod 28 drives the movable plate 29 to move upward, and the movable plate 29 drives the pipe to move upward. When the pipe moves upward to the specified position, it pushes the pipe to slide backward on the three groups of rollers 30, so that the pipe contacts the positioning device, which plays a role in adjusting the height of the pipe.

[0033] As a preferred embodiment of the above, the auxiliary device includes two sets of second telescopic tubes 31 and two sets of second telescopic rods 32, the two sets of second telescopic tubes 31 are respectively mounted on the front side and the rear side of the inner bottom end of the U-shaped frame 6, the two sets of second telescopic rods 32 are respectively mounted on the front side and the rear side of the bottom end of the movable plate 29, and the two sets of second telescopic rods 32 are respectively slidably connected to the two sets of second telescopic tubes 31;

[0034] By providing the second telescopic tube 31 and the second telescopic rod 32 , when the moving plate 29 moves, the two groups of second telescopic rods 32 slide on the two groups of second telescopic rods 32 to assist the moving plate 29 in moving, thereby improving the stability of the moving plate 29 .

[0035] As a preferred embodiment of the above, the inner ends of the two groups of arc-shaped clamping plates 11, the inner ends of the three groups of clamping plates 22 and the surfaces of the three groups of rollers 30 are all provided with a rubber layer;

[0036] Can avoid causing pipe wear.

[0037] The utility model is a flaring device for producing plastic pipes. When working, the first motor 13 is first turned on, and the first motor 13 drives the U-shaped frame 6 to rotate backward 90 degrees, so that the pipe is placed on the three groups of rollers 30. Then the second electric push rod 28 is turned on, and the second electric push rod 28 drives the moving plate 29 to move upward, and the moving plate 29 drives the pipe to move upward. When the pipe moves upward to a specified position, the pipe is pushed to slide backward on the three groups of rollers 30, so that the pipe contacts the positioning device, and then the first gear 25 is rotated through the rotating shaft 24, and the first gear 25 is meshed with the gear shaft 26, and the gear shaft 26 is meshed with the three groups of second gears 27, and the three groups of second gears 27 drive the three groups of screw rods 20 to rotate, and the three groups of screw rods 20 are threadedly connected with the three groups of screw sleeves 21, and the three groups of screw sleeves 21 drive the three groups of clamping plates 22 to rotate simultaneously. The first step moves inward, and the three groups of clamps 22 center the pipe. Then, the two groups of first electric push rods 7 are opened, and the two groups of first electric push rods 7 drive the two groups of arc clamps 11 to clamp and fix the pipe. Then, the first motor 13 is opened, and the first motor 13 drives the U-shaped frame 6 to reset. Then, the second motor 16 is opened, and the second motor 16 drives the bidirectional screw 14 to rotate. The bidirectional screw 14 is threadedly connected with the first slider 2 and the second slider 12. The first slider 2 drives the vertical plate 3 to move inward, and the second slider 12 drives the U-shaped frame 6 to move inward. When the pipes on the vertical plate 3 and the U-shaped frame 6 move to the specified position, the first motor 13 is turned off, so that the heating device heats and softens the position of the pipe to be expanded, and then the cylinder 4 is opened, and the cylinder 4 drives the expanding mold 5 to move to the right, so as to expand the pipe.

[0038] The expansion device for plastic pipe production of the utility model has common mechanical installation, connection or setting methods, which can be implemented as long as the beneficial effects can be achieved; the cylinder 4, the first electric push rod 7, the first motor 13, the second motor 16 and the second electric push rod 28 of the expansion device for plastic pipe production of the utility model are purchased on the market, and technicians in the industry only need to install and operate them according to the accompanying instruction manual.

[0039] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A expanding device for plastic pipe production, characterized in that: The invention comprises a base plate (1), a first slider (2), a vertical plate (3), a cylinder (4), a flaring die (5), a clamping device, a power mechanism and a positioning device. The power mechanism is mounted on the top of the base plate (1). The first slider (2) is connected to the power mechanism in cooperation with the vertical plate (3). The vertical plate (3) is mounted on the top of the first slider (2). The cylinder (4) is mounted on the left end of the vertical plate (3). The output end of the cylinder (4) passes through the vertical plate (3) and is connected to the flaring die (5). The clamping device is connected to the power mechanism in cooperation with the positioning device. The positioning device is mounted on the right rear side of the top of the base plate (1). The positioning device corresponds to the clamping device in position. The clamping device comprises a U-shaped frame (6), two groups of first electric push rods (7), four groups of first telescopic tubes (8), four groups of first telescopic rods (9), four groups of springs (10), two groups of arc-shaped clamping plates (11), a second slider (12), a first motor (13) and a lifting device. The second slider (12) is connected to the power mechanism in cooperation with the first electric push rod. The first motor (13) is mounted on the top of the second slider (12), the U-shaped frame (6) is mounted on the output end of the first motor (13), two groups of first electric push rods (7) are respectively mounted on the front end and the rear end of the U-shaped frame (6), the output ends of the two groups of first electric push rods (7) respectively pass through the front end and the rear end of the U-shaped frame (6) and are connected to the two groups of arc-shaped clamping plates (11), four groups of first telescopic tubes (8) are respectively mounted on the upper and lower parts of the front and rear sides of the U-shaped frame (6), four groups of first telescopic rods (9) are respectively slidably connected to the four groups of first telescopic tubes (8), the inner ends of the four groups of first telescopic rods (9) are respectively connected to the outer ends of the two groups of arc-shaped clamping plates (11), four groups of springs (10) are respectively sleeved on the four groups of first telescopic rods (9), one end of the four groups of springs (10) is connected to the four groups of first telescopic rods (9), and the other end of the four groups of springs (10) is connected to the four groups of first telescopic tubes (8), and the lifting device is mounted on the bottom of the U-shaped frame (6).

2. A plastic pipe production expansion device as claimed in claim 1, characterized in that: The power mechanism comprises a bidirectional screw (14), two groups of fixing seats (15), a second motor (16) and a guide rail (33). The two groups of fixing seats (15) are symmetrically mounted on the top of the base plate (1), the second motor (16) is mounted on the right end of the right fixing seat (15), the bidirectional screw (14) is rotatably mounted between the two groups of fixing seats (15), the output end of the second motor (16) passes through the right fixing seat (15) and is connected to the right end of the bidirectional screw (14), the guide rail (33) is mounted on the top of the base plate (1), the first slider (2) and the second slider (12) are both connected and provided with threaded holes in the middle part, the first slider (2) and the second slider (12) are both threadedly connected to the bidirectional screw (14), and the bottom ends of the first slider (2) and the second slider (12) are both slidably connected to the guide rail (33).

3. A plastic pipe production expansion device as claimed in claim 2, characterized in that: The positioning device comprises a three-jaw chuck (17), a base (18), three groups of screws (20), three groups of screw sleeves (21), three groups of clamping plates (22) and a transmission device. The three-jaw chuck (17) is mounted on the base (18), and the base (18) is mounted on the right rear side of the top end of the bottom plate (1). The three-jaw chuck (17) corresponds to the position of the U-shaped frame (6). The three-jaw chuck (17) is in the same central position as the expansion mold (5). A through hole is provided in the middle of the three-jaw chuck (17). The front end of the three-jaw chuck (17) is evenly spaced. Three groups of slide grooves (19) are provided, three groups of screw rods (20) are rotatably installed inside the three groups of slide grooves (19), a transmission device is installed at the rear end of the three-jaw chuck (17), the transmission device is matched and connected with the inner ends of the three groups of slide grooves (19), three groups of screw sleeves (21) are respectively threadedly connected with the three groups of screw rods (20), three groups of clamping plates (22) are respectively installed at the front ends of the three groups of screw sleeves (21), the three groups of clamping plates (22) are located at the front side of the three-jaw chuck (17), and the three groups of screw sleeves (21) are slidably connected with the three groups of slide grooves (19).

4. A plastic pipe production expansion device as claimed in claim 3, characterized in that: The transmission device comprises a transmission box (23), a rotating shaft (24), a first gear (25), a gear shaft (26) and three groups of second gears (27). The transmission box (23) is mounted at the middle of the rear end of the three-jaw chuck (17). The transmission box (23) is communicated with a through hole in the middle of the three-jaw chuck (17). The rotating shaft (24) is rotatably mounted on the top of the transmission box (23). The bottom of the rotating shaft (24) is located inside the transmission box (23). The first gear (25) is mounted at the bottom end of the rotating shaft (24). The first gear (25) is meshed with the rear end of the gear shaft (26). The gear shaft (26) is rotatably mounted inside the transmission box (23). The three groups of second gears (27) are respectively mounted on the inner ends of the three groups of screw rods (20). The three groups of second gears (27) are all meshed with the front ends of the gear shaft (26).

5. A plastic pipe production expansion device as claimed in claim 4, characterized in that: The lifting device comprises a second electric push rod (28), a movable plate (29), three groups of rollers (30) and an auxiliary device. The second electric push rod (28) is mounted at the middle of the inner bottom end of the U-shaped frame (6). The movable plate (29) is mounted at the output end of the second electric push rod (28). Three groups of mounting grooves are arranged at the top of the movable plate (29). The three groups of rollers (30) are rotatably mounted in the three groups of mounting grooves at the top of the movable plate (29). The auxiliary device is mounted at the inner bottom end of the U-shaped frame (6). The auxiliary device is cooperatively connected with the movable plate (29).

6. A plastic pipe production expansion device as claimed in claim 5, characterized in that: The auxiliary device comprises two groups of second telescopic tubes (31) and two groups of second telescopic rods (32). The two groups of second telescopic tubes (31) are respectively mounted on the front side and the rear side of the inner bottom end of the U-shaped frame (6). The two groups of second telescopic rods (32) are respectively mounted on the front side and the rear side of the bottom end of the moving plate (29). The two groups of second telescopic rods (32) are respectively slidably connected to the two groups of second telescopic tubes (31).

7. A plastic pipe production expansion device as claimed in claim 6, characterized in that: The inner ends of the two groups of arc-shaped clamping plates (11), the inner ends of the three groups of clamping plates (22) and the surfaces of the three groups of rotating rollers (30) are all provided with rubber layers.

Images