An expansion device for PVC pipe production

Abstract

The present application relates to an expansion device for the production of PVC pipes, belonging to the technical field of PVC pipe production and processing. In order to solve the problem that the thread processing of PVC pipes is likely to reduce the structural strength of PVC pipes, it includes an expansion die. An adjustment hole is provided in the expansion die, and an adjustment rod is inserted into the adjustment hole. A through hole is provided on the outer side wall of the expansion die, and the through hole communicates with the adjustment hole; a first sliding groove and a second sliding groove are provided on the inner wall of the adjustment hole. The first sliding groove and the second sliding groove are provided along the length direction of the die. The position of the first sliding groove is staggered from that of the through hole, and the second sliding groove is aligned with the through hole. A connecting groove is provided at one end of the first sliding groove close to the through hole, and the first sliding groove and the through hole are communicated through the connecting groove. A receiving groove is provided on the inner wall at one end of the second sliding groove far from the through hole; a plugging component and a cutting component are provided on the side wall of the adjustment rod. The plugging component is slidably arranged in the second sliding groove, and the cutting component is slidably arranged in the first sliding groove. The present application has the effect of maintaining the structural strength of the PVC pipe during thread processing.

Description

Technical Field

[0001] This application relates to the technical field of PVC pipe production and processing, and particularly relates to an expansion device for PVC pipe production. Background Art

[0002] PVC pipe is a plastic pipe extruded by hot pressing after mixing polyvinyl chloride resin with stabilizers, lubricants, etc. It is commonly used in applications such as drainage, wastewater, chemicals, heating liquids and coolants, food, ultra-pure liquids, mud, gases, compressed air, and vacuum systems, and is a pipe with a wide range of applications.

[0003] In related technologies, during the production of PVC pipes, in order to improve the strength, toughness, impact resistance, fatigue resistance, low-temperature resistance, etc. of PVC pipes, or to set a larger-diameter mating port at the pipe orifice of PVC pipes, a two-way expansion and stretching process for PVC pipes is added during the production process of PVC pipes. Two-way stretching refers to stretching in the axial and radial directions of the PVC pipe; the two-way expansion and stretching process refers to inserting an expansion and stretching die into the PVC pipe. The expansion and stretching die includes two cylinders with different diameters, and a tapered column is connected between the two cylinders. After the small-diameter cylinder is inserted into the PVC pipe and passes through the PVC pipe, one end of the small-diameter cylinder is connected to a traction device, and the traction device pulls the expansion and stretching die to further pass through the PVC pipe. The tapered column moves to be in contact with the inner wall of the PVC pipe, and the pipe wall of the PVC pipe is expanded under the guiding action of the side wall of the tapered column. After the PVC pipe is expanded to the same thickness as the large-diameter cylinder, the two-way expansion and stretching of the PVC pipe can be achieved.

[0004] After the PVC pipe is expanded and stretched, in order to achieve the use connection of the PVC pipe, internal threads need to be opened on the inner wall of the PVC pipe; generally, the threading of PVC pipes is cold-formed on the inner wall of the PVC pipe using a threading device after the PVC pipe is cooled and formed; however, after the PVC pipe is cooled, the internal structure of the PVC pipe has been stabilized, and cold-forming is likely to affect the internal structure of the PVC pipe, reducing the structural strength of the PVC pipe. Summary of the Invention

[0005] In order to maintain the structural strength when processing threads on PVC pipes, this application provides an expansion device for PVC pipe production.

[0006] The expansion device for PVC pipe production provided by this application adopts the following technical solutions:

[0007] An expansion device for PVC pipe production, comprising an expansion die. An adjustment hole is provided in the expansion die, and an adjustment rod is inserted into the adjustment hole. A through hole is provided in the outer side wall of the expansion die, and the through hole communicates with the adjustment hole; a first sliding groove and a second sliding groove are provided in the inner wall of the adjustment hole. The first sliding groove and the second sliding groove are provided along the length direction of the die. The position of the first sliding groove is offset from the through hole, and the second sliding groove is aligned with the through hole. A connecting groove is provided at one end of the first sliding groove close to the through hole, and the first sliding groove and the through hole are connected through the connecting groove. A receiving groove is provided in the inner wall at one end of the second sliding groove away from the through hole; a blocking component and a cutting component are provided on the side wall of the adjustment rod. The blocking component is slidably arranged in the second sliding groove, and the cutting component is slidably arranged in the first sliding groove. The through hole is used for the blocking component and the cutting component to be inserted respectively.

[0008] By adopting the above technical solution, after the PVC pipe is expanded and stretched, the PVC pipe is not cooled first. The expansion die is inserted into the stretched PVC pipe again. At this time, the adjustment rod is pulled to move along the length direction of the adjustment hole. The adjustment rod applies a pulling force to the blocking component, causing the blocking component to move from the through hole into the second sliding groove; the adjustment rod simultaneously pulls the cutting component to move along the first sliding groove, and the cutting component moves from the first sliding groove into the connecting groove. At this time, the adjustment rod is rotated, and the adjustment rod drives the cutting component to move from the connecting groove to align with the through hole, and at the same time drives the blocking component to rotate and insert into the receiving groove; the cutting component protrudes from the through hole and protrudes along the outer side wall of the expansion die, and the cutting component cuts into the inner wall of the PVC pipe. At this time, the expansion die is driven to rotate and simultaneously move along the length direction of the PVC pipe, and the cutting component can be driven to cut a threaded section on the inner wall of the PVC pipe. The cooperation of the adjustment hole and the adjustment rod, the settings of the first sliding groove, the second sliding groove, the connecting groove and the receiving groove, and the settings of the blocking component and the cutting component can quickly perform thread processing on the inner wall of the PVC pipe after the expansion die finishes stretching the PVC pipe. At this time, the PVC pipe is still in a relatively soft state at a high temperature, and the influence on the internal structure of the PVC pipe can be reduced when the expansion die performs thread processing on the PVC pipe, thereby maintaining the structural strength of the PVC pipe during thread processing.

[0009] Preferably, the cutting component includes a mounting block, a cutting head and a spring. The mounting block is fixedly connected to the side wall of the adjustment rod. The spring is connected to the side wall of the mounting block. The cutting head is connected to the end of the spring away from the mounting block; the mounting block is slidably connected in the first sliding groove, and the cutting head is arc-shaped.

[0010] By adopting the above technical solution, when the adjusting rod pulls the cutting assembly, the mounting block is pulled to move along the first slide groove, and the mounting block drives the cutting head to move from the first slide groove to the connecting groove; when the adjusting rod rotates the cutting assembly, the adjusting rod drives the mounting block to make the cutting head move from the connecting groove to be aligned with the through hole, and the spring force can push the cutting head to extend out of the through hole and protrude along the outer wall of the expansion mold. The cutting head protrudes and cuts into the inner wall of the PVC pipe. At this time, the expansion mold is driven to rotate and move along the length direction of the PVC pipe at the same time, which can drive the cutting head to cut a threaded segment on the inner wall of the PVC pipe.

[0011] Preferably, the blocking assembly includes a slider, an elastic member and a blocking block, the slider is fixedly connected to the side wall of the adjusting rod, the elastic member is connected to the side wall of the slider, the blocking block is connected to the elastic member, the slider is slidably connected in the second slide groove, and the side wall of the blocking block is set as an inclined wall.

[0012] By adopting the above technical solution, when the adjusting rod pulls the blocking assembly, the adjusting rod applies a pulling force to the slider, and the slider then applies a pulling force to the blocking block through the elastic member. Under the guidance of its own inclined wall, the blocking block compresses the elastic member at the same time and further moves into the second sliding groove; when the adjusting rod rotates the blocking assembly, it will drive the slider to rotate and insert the blocking block into the accommodating groove, thereby achieving the purpose of making way for the through hole.

[0013] Preferably, the elastic member is an elastic bending plate, one side of the elastic member is connected to the slider, and the other side of the elastic member is connected to the blocking block; the inner wall of the through hole close to the second slide groove is set as a sloped wall that adapts to and adheres to the inclined wall of the blocking block.

[0014] Generally, the elastic part is a spring, and when the blocking block enters the second slide groove from the through hole, the blocking block will tilt and rotate, and the spring will easily bend and deform, resulting in spring imbalance; by adopting the above technical solution, the elastic part is set as an elastic bending plate, and when the blocking block tilts and rotates, the elastic part bends and deforms accordingly, and no bending imbalance will occur; at the same time, the cooperation between the inclined wall of the blocking block and the inclined wall of the through hole can reduce the resistance of the blocking block when entering the second slide groove.

[0015] Preferably, the side wall of the cutting head is provided with a filling portion, the filling portion is arranged along the circumference of the cutting head, the filling portion is connected to the side wall of the mounting block, and the filling portion is used to be inserted into the through hole.

[0016] By adopting the above technical solution, when the cutting head extends from the through hole, the filling part is inserted into the through hole, and the side wall of the filling part is flush with the outer wall of the expansion mold, so as to avoid direct misalignment between the side wall of the mounting block and the outer wall of the expansion mold, resulting in the PVC pipe being scratched by the edge of the inner wall of the through hole.

[0017] Preferably, a protective shell is slidably connected to the inner side wall of the first chute. The cutting head is rotatably inserted into the protective shell, and a protective groove adapted to the side wall of the cutting head is formed on the inner wall of the protective shell. The mounting block can drive the protective shell to slide along the first chute and is rotatably arranged relative to the protective shell.

[0018] By adopting the above technical solution, when the cutting head rotates into the first chute, it will enter the protective shell along the opening of the protective shell at the same time. At the same time, the cutting edge of the cutting head is inserted into the protective groove. Then, the adjusting rod is pushed to drive the mounting block to make the cutting head slide into the first chute. At the same time, the protective shell can protect the cutting head and avoid the situation that the cutting edge of the cutting head is worn due to the relative sliding between the cutting head and the inner wall of the first chute.

[0019] Preferably, guide wheels are rotatably connected to the two inner side walls of the protective shell, and the guide wheels are located on the inner wall of the protective shell near the opening. An included angle is formed between the side walls of the two guide wheels, and the included angle between the two guide wheels is the same as the included angle of the side wall of the cutting head.

[0020] By adopting the above technical solution, when the cutting head enters the protective shell, the two side walls of the cutting edge of the cutting head will be in contact with the two guide wheels and enter the protective shell under the guidance of the two guide wheels. The guide wheels can protect the cutting head and avoid the contact between the cutting head and the end wall of the protective shell, and avoid the damage of the cutting edge of the cutting head caused by the contact between the protective shell and the cutting edge of the cutting head. At the same time, the two guide wheels can rub the two side walls of the cutting edge of the cutting head to sharpen the cutting edge of the cutting head.

[0021] Preferably, a sliding plate that moves synchronously with the expansion die is arranged on one side of the expansion die. A matching hole for the expansion die to pass through is formed on the side wall of the sliding plate. A support block is slidably arranged on the inner wall of the matching block hole, and the support block can rotate circumferentially along the inner wall of the matching hole. The support block is used to be in contact with the outer wall of the PVC pipe and correspond to the position of the cutting head.

[0022] By adopting the above technical solution, when threading the PVC pipe, the sliding plate is moved to make the expansion die and the PVC pipe pass through the matching hole. When the cutting head cuts into the inner wall of the PVC pipe, the support block is rotated to a position opposite to the cutting head, and the support block is simultaneously in contact with the outer wall of the PVC pipe. When the expansion die rotates and simultaneously moves along the length direction of the PVC pipe, the sliding plate moves synchronously with the expansion die. At the same time, the motor is started to make the gear drive the tooth disc to rotate, driving the support block to rotate circumferentially along the inner wall of the matching hole, so that the support block can always maintain a corresponding position with the cutting head, and the PVC pipe at the cutting position of the cutting head can be supported, avoiding the situation that the pipe wall of the PVC pipe is deformed when it is cut.

[0023] Preferably, a support platform for supporting the PVC pipe is arranged at the lower end of the inner side wall of the matching hole, and a through groove for the support block to move through is formed through the support platform.

[0024] By adopting the above technical solution, when the PVC pipe passes through the mating hole, the support platform can support the PVC pipe, and at the same time, the support block will pass through the through groove, avoiding the interference of the support platform on the movement of the support block.

[0025] In summary, the present application includes at least one of the following beneficial technical effects:

[0026] 1. The cooperation of the adjustment hole and the adjustment rod, the settings of the first chute, the second chute, the connection groove and the accommodation groove, and the settings of the plugging component and the cutting component can quickly process the inner wall of the PVC pipe with threads after the expansion mold finishes stretching the PVC pipe. At this time, the PVC pipe is still in a relatively soft state at high temperature. When the expansion mold processes the threads of the PVC pipe, it can reduce the influence on the internal structure of the PVC pipe, thereby maintaining the structural strength of the PVC pipe when processing the threads.

[0027] 2. The protective shell can protect the cutting head, avoiding the situation where the cutting edge of the cutting head is worn due to the relative sliding of the cutting head with the inner wall of the first chute.

[0028] 3. The guide wheel can protect the cutting head, avoiding the contact of the cutting head with the end wall of the protective shell and preventing the damage of the cutting edge of the cutting head caused by the contact between the protective shell and the cutting edge of the cutting head. Description of the Drawings

[0029] Figure 1 is a schematic structural diagram of an expansion device for producing PVC pipes in an embodiment of the present application.

[0030] Figure 2 is a schematic cross-sectional view for showing the positional relationship between the first chute and the second chute in an embodiment of the present application.

[0031] Figure 3 is a schematic cross-sectional view for showing the positional relationship between the through hole and the inclined surface wall in an embodiment of the present application.

[0032] Figure 4 is a schematic cross-sectional view for showing the positional relationship between the adjustment rod and the plugging component and the cutting component in an embodiment of the present application.

[0033] Figure 5 is a schematic structural diagram for showing the positional relationship between the support block and the sliding plate in an embodiment of the present application.

[0034] Figure 6 is Figure 4 an enlarged schematic view of part A in

[0035] Description of reference numerals: 1. Expansion die; 11. Adjustment hole; 12. Adjustment rod; 13. First chute; 14. Second chute; 15. Connection groove; 16. Accommodation groove; 17. Through hole; 171. Inclined wall; 2. Cutting assembly; 21. Mounting block; 22. Cutting head; 221. Filling part; 23. Spring; 3. Sealing assembly; 31. Slide block; 32. Elastic member; 33. Sealing block; 331. Inclined wall; 4. Protective shell; 41. Protective groove; 42. Guide wheel; 5. Slide plate; 51. Matching hole; 52. Support block; 53. Support platform; 531. Through groove. Detailed implementation mode

[0036] The following further elaborates on this application in conjunction with the attached Figures 1-6 drawings.

[0037] The embodiment of this application discloses an expansion device for PVC pipe production. Refer to Figure 1 , the expansion device for PVC pipe production includes an expansion die 1. The expansion die 1 includes two cylinders with different diameters, and a conical cylinder is connected between the two cylinders. One end diameter of the conical cylinder is the same as that of the large-diameter cylinder, and the other end diameter of the conical cylinder is the same as that of the small-diameter cylinder. The conical cylinder is integrally formed between the two cylinders. The expansion die 1 is slidably connected to a machine base and is connected to a traction device on the machine base; a slide plate 5 is also slidably connected to the machine base, and the slide plate 5 can move synchronously with the expansion die 1.

[0038] Refer to Figure 2 and Figure 3 , an adjustment hole 11 is opened in the expansion die 1. The adjustment hole 11 is opened along the axial direction of the expansion die 1. An adjustment rod 12 is inserted into the adjustment hole 11. The adjustment rod 12 is slidably connected and rotationally connected to the adjustment hole 11; a through hole 17 is opened on the outer side wall of the expansion die 1. The through hole 17 communicates with the adjustment hole 11. The inner wall of the adjustment hole 11 is provided with a first chute 13 and a second chute 14. The first chute 13 and the second chute 14 are opened along the length direction of the die. The first chute 13 is staggered with the through hole 17 in position, and the second chute 14 is aligned with the through hole 17. A connection groove 15 is opened at one end of the first chute 13 close to the through hole 17. The first chute 13 and the through hole 17 are connected through the connection groove 15. The inner wall of the second chute 14 at the end far from the through hole 17 is provided with an accommodation groove 16.

[0039] Refer to Figure 2 and Figure 4 , a sealing assembly 3 and a cutting assembly 2 are arranged on the side wall of the adjustment rod 12. The cutting assembly 2 includes a mounting block 21, a cutting head 22 and a spring 23. The cutting head 22 is arc-shaped; the mounting block 21 is fixedly connected to the side wall of the adjustment rod 12. The spring 23 is connected to the side wall of the mounting block 21. The cutting head 22 is fixedly connected to the end of the spring 23 far from the mounting block 21. The mounting block 21 is slidably connected in the first chute 13. The side walls on both sides of the cutting head 22 are arranged at an angle.

[0040] Refer to Figure 2 、 Figure 3 and Figure 4 As shown in FIGS. Figure 2 , Figure 3 and Figure 4 , the plugging assembly 3 includes a slider 31, an elastic member 32 and a plugging block 33. The slider 31 is fixedly connected to the side wall of the adjusting rod 12. The circumferential positions of the slider 31 and the mounting block 21 are offset along the adjusting rod 12. The elastic member 32 is fixedly connected to the side wall of the slider 31. The elastic member 32 is a bent plate made of elastic metal. The plugging block 33 is fixedly connected to the elastic member 32. The slider 31 is slidably connected in the second chute 14. One side wall of the plugging block 33 is provided with an inclined wall 331. The inner wall of the through hole 17 close to the second chute 14 is provided with an inclined surface wall 171. The inclined surface wall 171 of the through hole 17 is adapted to and abuts against the inclined wall 331 of the plugging block 33.

[0041] When the PVC pipe is expanded and stretched, the plugging block 33 is inserted into the through hole 17 at this time, and the outer side wall of the plugging block 33 is flush with the outer side wall of the expansion die 1. The small-diameter cylinder of the expansion die 1 is inserted into the PVC pipe and then passes through the PVC pipe. One end of the small-diameter cylinder of the expansion die 1 is connected to the traction device. The traction device pulls the expansion and stretching die to further pass through the PVC pipe. The conical column of the expansion die 1 moves to abut against the inner wall of the PVC pipe. The inner wall of the PVC pipe is expanded under the guiding action of the side wall of the conical column of the expansion die 1. After the PVC pipe is expanded to be as thick as the large-diameter cylinder of the expansion die 1, the large-diameter cylinder of the expansion die 1 passes through the PVC pipe again, and the two-way expansion and stretching of the PVC pipe can be realized.

[0042] After the PVC pipe is expanded and stretched, the PVC pipe is not cooled first. The expansion die 1 is inserted into the stretched PVC pipe again. At this time, the adjusting rod 12 is pulled to move along the length direction of the adjusting hole 11. The adjusting rod 12 applies a pulling force to the slider 31. The slider 31 then applies a pulling force to the plugging block 33 through the elastic member 32. Under the guiding action of its own inclined wall 331 and the inclined surface wall 171 of the through hole 17, the plugging block 33 compresses the elastic member 32 and further moves into the second chute 14. The adjusting rod 12 simultaneously pulls the mounting block 21 to move along the first chute 13. The mounting block 21 drives the cutting head 22 to move from the first chute 13 into the connecting groove 15. At this time, the adjusting rod 12 is rotated. The adjusting rod 12 drives the mounting block 21 to align the cutting head 22 with the through hole 17 from the connecting groove 15, and at the same time drives the slider 31 to rotate the plugging block 33 into the receiving groove 16. The elastic force of the spring 23 can push the cutting head 22 to protrude from the through hole 17 and protrude along the outer side wall of the expansion die 1. When the cutting head 22 protrudes, it cuts into the inner wall of the PVC pipe. At this time, the expansion die 1 is driven to rotate and simultaneously move along the length direction of the PVC pipe, and the cutting head 22 can be driven to cut out a threaded section on the inner wall of the PVC pipe. After the threaded section is opened in the PVC pipe, it can also promote the water flow to flow along the wall when conveying water, reducing the noise of the high-rise water flow flowing down.

[0043] Referring to Figure 5 , a mating hole 51 is formed in the side wall of the skateboard 5, a support block 52 is slidably arranged on the inner wall of the mating hole 51, a gear disk is rotatably connected in the skateboard 5, and the support block 52 can pass through the annular groove on the inner wall of the mating hole 51 and be connected to the inner wall of the gear disk; a gear is connected to the outer side wall of the skateboard 5, the gear meshes with the gear disk, and the gear is driven by a motor.

[0044] When threading the PVC pipe, move the skateboard 5 so that the expansion die 1 and the PVC pipe pass through the mating hole 51. When the cutting head 22 cuts into the inner wall of the PVC pipe, rotate the support block 52 to a position opposite to the cutting head 22. The support block 52 is simultaneously attached to the outer wall of the PVC pipe. When the expansion die 1 rotates and simultaneously moves along the length direction of the PVC pipe, the skateboard 5 moves synchronously with the expansion die 1. At the same time, start the motor to drive the gear disk to rotate by the gear, driving the support block 52 to rotate circumferentially along the inner wall of the mating hole 51, so that the support block 52 and the cutting head 22 can always maintain a corresponding position, and the PVC pipe at the cutting position of the cutting head 22 can be supported to avoid the deformation of the pipe wall when the PVC pipe is cut.

[0045] Referring to Figure 5 , a support platform 53 is fixedly connected to the lower end of the inner side wall of the mating hole 51, and a through groove 531 is formed through the support platform 53; when the PVC pipe passes through the mating hole 51, the support platform 53 can support the PVC pipe, and at the same time, the support block 52 will pass through the through groove 531 to avoid the interference of the support platform 53 on the movement of the support block 52.

[0046] Referring to Figure 3 and Figure 4 , a filling part 221 is arranged on the side wall of the cutting head 22, the filling part 221 is arranged along the circumference of the cutting head 22, the filling part 221 is connected to the side wall of the mounting block 21, and when the cutting head 22 extends out of the through hole 17, the filling part 221 is inserted into the through hole 17, and the side wall of the filling part 221 is flush with the outer side wall of the expansion die 1 to avoid the direct misalignment between the side wall of the mounting block 21 and the outer side wall of the expansion die 1, resulting in the PVC pipe being scratched by the edge of the inner wall of the through hole 17.

[0047] Referring to Figure 2 , Figure 4 and Figure 6 , a protective shell 4 is connected to one side of the mounting block 21, the protective shell 4 is rotatably connected to the inner wall of the first chute 13 and can slide along the first chute 13, a protective groove 41 adapted to the side wall of the cutting head 22 is formed in the inner wall of the protective shell 4, and the mounting block 21 is rotatably arranged relative to the protective shell 4; when the adjusting rod 12 pulls the mounting block 21 to move, the protective shell 4 can be driven to move synchronously.

[0048] After the threading of the PVC pipe is completed, the adjusting rod 12 can be rotated to drive the cutting head 22 to rotate towards the connecting groove 15. Since the cutting head 22 is arc-shaped, the cutting head 22 rotates into the connecting groove 15 under the guidance of its own arc-shaped wall and further moves into the first sliding groove 13. When the cutting head 22 enters the first sliding groove 13, it will enter the protective shell 4 along the opening of the protective shell 4. At the same time, the cutting edge of the cutting head 22 is inserted into the protective groove 41. Then, the adjusting rod 12 is pushed to drive the mounting block 21 to make the cutting head 22 slide into the first sliding groove 13. At the same time, the protective shell 4 can protect the cutting head 22 to avoid the wear of the cutting edge of the cutting head 22 caused by the relative sliding of the cutting head 22 and the inner wall of the first sliding groove 13.

[0049] Referring to Figure 6 , on both inner side walls of the protective shell 4, there are rotatably connected guide wheels 42. The guide wheels 42 are located on the inner wall of the protective shell 4 near the opening. The included angle between the side walls of the two guide wheels 42 is set, and the included angle between the two guide wheels 42 is the same as the included angle of the side wall of the cutting head 22.

[0050] When the cutting head 22 enters the protective shell 4, the two side walls of the cutting edge of the cutting head 22 will be in contact with the two guide wheels 42 and enter the protective shell 4 under the guidance of the two guide wheels 42. The guide wheels 42 can protect the cutting head 22 to avoid the contact between the cutting head 22 and the end wall of the protective shell 4 and avoid the damage of the cutting edge of the cutting head 22 caused by the contact between the protective shell 4 and the cutting edge of the cutting head 22.

[0051] The implementation principle of the expansion device for producing PVC pipes in the embodiment of the present application is as follows:

[0052] After the PVC pipe is expanded and stretched, the PVC pipe is not cooled first. The expansion die 1 is inserted into the stretched PVC pipe again. At this time, the adjusting rod 12 is pulled to move along the length direction of the adjusting hole 11. The adjusting rod 12 applies a pulling force to the slider 31, and the slider 31 then applies a pulling force to the blocking block 33 through the elastic member 32. Under the guiding action of its own inclined wall 331 and the inclined surface wall 171 of the through hole 17, the blocking block 33 compresses the elastic member 32 at the same time and further moves into the second sliding groove 14; the adjusting rod 12 simultaneously pulls the mounting block 21 to move along the first sliding groove 13. The mounting block 21 drives the cutting head 22 to move from the first sliding groove 13 into the connecting groove 15. At this time, the adjusting rod 12 is rotated. The adjusting rod 12 drives the mounting block 21 to move the cutting head 22 from the connecting groove 15 to align with the through hole 17, and at the same time drives the slider 31 to rotate the blocking block 33 and insert it into the receiving groove 16; the elastic force of the spring 23 can push the cutting head 22 to protrude from the through hole 17 and protrude along the outer wall of the expansion die 1. While the cutting head 22 protrudes, it cuts into the inner wall of the PVC pipe. At this time, the expansion die 1 is driven to rotate and simultaneously move along the length direction of the PVC pipe, which can drive the cutting head 22 to cut out a threaded section on the inner wall of the PVC pipe. The cooperation of the adjusting hole 11 and the adjusting rod 12, the settings of the first sliding groove 13, the second sliding groove 14, the connecting groove 15 and the receiving groove 16, and the settings of the blocking assembly 3 and the cutting assembly 2 can quickly perform thread processing on the inner wall of the PVC pipe after the expansion die 1 finishes stretching the PVC pipe. At this time, the PVC pipe is still in a relatively soft state at high temperature. When the expansion die 1 performs thread processing on the PVC pipe, it can reduce the influence on the internal structure of the PVC pipe, thereby maintaining the structural strength of the PVC pipe during thread processing.

[0053] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereby. Therefore, all equivalent changes made according to the structure, shape, and principle of the present application should be covered within the protection scope of the present application.

Claims

1. An expansion device for PVC pipe production, comprising an expansion die (1), characterized in that, The expansion die (1) is provided with an adjustment hole (11) therein. An adjustment rod (12) is inserted into the adjustment hole (11). A through hole (17) is formed in the outer side wall of the expansion die (1), and the through hole (17) communicates with the adjustment hole (11). First and second sliding grooves (13) and (14) are formed in the inner wall of the adjustment hole (11). The first and second sliding grooves (13) and (14) are formed along the length direction of the die. The position of the first sliding groove (13) is offset from that of the through hole (17), and the second sliding groove (14) is aligned with the through hole (17). A connecting groove (15) is formed at one end of the first sliding groove (13) close to the through hole (17). The first sliding groove (13) and the through hole (17) are communicated through the connecting groove (15). A receiving groove (16) is formed in the inner wall at one end of the second sliding groove (14) far from the through hole (17). A plugging component (3) and a cutting component (2) are arranged on the side wall of the adjustment rod (12). The plugging component (3) is slidably arranged in the second sliding groove (14), and the cutting component (2) is slidably arranged in the first sliding groove (13). The through hole (17) is used for the plugging component (3) and the cutting component (2) to be inserted respectively.

2. The expanding device for PVC pipe production according to claim 1, characterized in that, The cutting component (2) includes a mounting block (21), a cutting head (22) and a spring (23). The mounting block (21) is fixedly connected to the side wall of the adjustment rod (12). The spring (23) is connected to the side wall of the mounting block (21). The cutting head (22) is connected to one end of the spring (23) far from the mounting block (21). The mounting block (21) is slidably connected in the first sliding groove (13), and the cutting head (22) is arc-shaped.

3. The expansion device for PVC pipe production according to claim 1, characterized in that, The plugging component (3) includes a slider (31), an elastic member (32) and a plugging block (33). The slider (31) is fixedly connected to the side wall of the adjustment rod (12). The elastic member (32) is connected to the side wall of the slider (31). The plugging block (33) is connected to the elastic member (32). The slider (31) is slidably connected in the second sliding groove (14), and one side wall of the plugging block (33) is provided with an inclined wall (331).

4. The expanding device for PVC pipe production according to claim 3, characterized in that, The elastic member (32) is an elastic bending plate. One bent side of the elastic member (32) is connected to the slider (31), and the other bent side of the elastic member (32) is connected to the plugging block (33). The inner wall of the through hole (17) close to the second sliding groove (14) is provided with an inclined surface wall (171) adapted to and in contact with the inclined wall (331) of the plugging block (33).

5. The expansion device for PVC pipe production according to claim 2, characterized in that, A filling portion (221) is arranged on the side wall of the cutting head (22). The filling portion (221) is arranged along the circumferential direction of the cutting head (22). The filling portion (221) is connected to the side wall of the mounting block (21). The filling portion (221) is used for being inserted into the through hole (17).

6. The expansion device for PVC pipe production according to claim 2, characterized in that, A protective shell (4) is slidably connected to the inner side wall of the first sliding groove (13). The cutting head (22) is rotatably inserted into the protective shell (4), and a protective groove (41) adapted to the side wall of the cutting head (22) is formed on the inner wall of the protective shell (4). The mounting block (21) can drive the protective shell (4) to slide along the first sliding groove (13) and is rotatably arranged relative to the protective shell (4).

7. The expanding device for PVC pipe production according to claim 6, characterized in that, Guide wheels (42) are rotatably connected to the two inner side walls of the protective shell (4). The guide wheels (42) are located on the inner wall of the protective shell (4) near the opening. An included angle is formed between the side walls of the two guide wheels (42), and the included angle between the two guide wheels (42) is the same as the included angle of the side wall of the cutting head (22).

8. The expansion device for PVC pipe production according to claim 2, characterized in that, A sliding plate (5) that moves synchronously with the expansion die (1) is arranged on one side of the expansion die (1). A matching hole (51) for the expansion die (1) to pass through is formed in the side wall of the sliding plate (5). A support block (52) is slidably arranged on the inner wall of the matching hole (51). The support block (52) can rotate circumferentially along the inner wall of the matching hole (51). The support block (52) is used to be in contact with the outer wall of the PVC pipe and is corresponding to the position of the cutting head (22).

9. The expansion device for PVC pipe production according to claim 8, characterized in that, A support table (53) for supporting the PVC pipe is arranged at the lower end of the inner side wall of the matching hole (51). A through groove (531) for the support block (52) to move through is formed through the support table (53).

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