Online diameter expanding device for plastic pipe

Abstract

The invention relates to the technical field of plastic pipe production, in particular to a plastic pipe online diameter expanding device which comprises a shell and a circular groove formed in the front side of the shell, a diameter expanding mechanism is installed at the center of the circular groove, and a shape preserving mechanism is installed on the inner ring wall of the circular groove. A driving mechanism for driving the diameter expanding mechanism and the shape preserving mechanism to rotate reversely is mounted on the shell, and a guiding mechanism is mounted between the diameter expanding mechanism and the shape preserving mechanism. The expanding mechanism and the shape preserving mechanism are in linkage fit to expand the diameter of the plastic pipe, when the expanding assembly I pushes the expanding plate to expand outwards to expand the diameter of the plastic pipe, the retaining plate can be clamped on the outer wall of the plastic pipe and expand outwards along with the expanding plate, and the retaining plate rotates in the circumferential direction of the plastic pipe in the outward expanding process, so that the diameter of the plastic pipe is increased, and the diameter of the plastic pipe is increased. And the outer wall of the plastic pipe is kept through the keeping plate, and the situations that the wall thickness of the plastic pipe is not uniform and the outer wall is not flat can be avoided.

Description

Technical Field

[0001] This invention relates to the field of plastic pipe manufacturing technology, specifically to an online plastic pipe diameter expansion device. Background Technology

[0002] Plastic pipes are generally made from synthetic resins with added stabilizers, lubricants, plasticizers, etc., and are processed by extrusion in a pipe-making machine using a "plastic" method. Ordinary plastic pipes are usually connected by fusion welding, but for large-diameter plastic pipes, it is difficult to connect them by fusion welding. Therefore, in the process of plastic pipe production and processing, in order to facilitate the connection between large-diameter pipes, one end of the plastic pipe is usually enlarged.

[0003] A fixed mold is typically used to extrude the softened plastic end. While this method uses a simple structure, it can easily lead to uneven wall thickness in the expanded section, excessive material stretching and thinning, and stress concentration and abrupt shape changes at the connection between the expanded and unexpanded sections, affecting the connection strength and sealing performance of the pipe.

[0004] To improve wall thickness uniformity, existing technologies, such as Chinese invention patent publication number CN116423815A, disclose a plastic pipe expansion device and its usage method. This device uses a drive motor to rotate the expansion component and, in conjunction with an external clamping device, expands the plastic pipe online, achieving multi-directional heating and expansion of the plastic pipe.

[0005] However, after in-depth analysis, the existing technology still has the following limitations: the pipe expansion equipment adopts a unidirectional rotation expansion method, and the plastic pipe will be subjected to a torsional torque in one direction during the expansion process, which can easily lead to torsional deformation at the connection between the expanded section and the unexpanded section; and the plastic pipe will undergo tensile deformation under the action of the expansion device, which can easily lead to problems such as inconsistent pipe wall thickness and uneven pipe outer wall. Summary of the Invention

[0006] To address the aforementioned problems, the present invention provides an online expansion device for plastic pipes, comprising a housing and a circular groove formed on the front side of the housing, an expansion mechanism installed at the center of the circular groove, a conformal mechanism installed on the inner ring wall of the circular groove, and a drive mechanism installed on the housing.

[0007] The diameter expansion mechanism includes a central rotating shaft rotatably installed inside the housing and coaxial with the circular groove. Several diameter expansion plates are evenly distributed around the outer circumference of the central rotating shaft. An expansion component is installed on the central rotating shaft. A movable disc located behind the diameter expansion plates is slidably sleeved on the outer side of the central rotating shaft.

[0008] The conformal mechanism includes a movable ring rotatably mounted on the inner ring wall of a circular groove. Several retaining plates are evenly distributed circumferentially on the inner side of the movable ring. Several expansion components II are evenly mounted circumferentially on the movable ring to drive the corresponding retaining plates to expand outward. Clamping components are mounted on the expansion components II to drive the retaining plates to clamp inward.

[0009] When the expansion plate is pushed outward by the expansion component to expand the diameter of the plastic tube, the retaining plate clamps the outer wall of the plastic tube and moves synchronously with the expansion plate. The driving mechanism makes the expansion plate and the retaining plate rotate around the circumference of the plastic tube at the same speed but in opposite directions.

[0010] The expanding mechanism is equipped with a limiting mechanism to limit the movement distance of the expanding plate and the retaining plate; a guiding mechanism is installed between the expanding mechanism and the retaining mechanism to guide the shaping of the inner and outer sides of the plastic tube.

[0011] In one possible implementation, the expansion assembly includes two frustums slidably mounted inside a central rotating shaft and connected end to end. An expansion rod symmetrically distributed front and rear is fixedly connected to the side of the expansion plate near the central rotating shaft. One end of each expansion rod, near the center of the central rotating shaft, slides through the shaft and is fixedly connected to a wedge block. The inclined surface of the wedge block slides in engagement with the inclined surface of the corresponding frustum. A return spring, sleeved outside the expansion rod, is fixedly connected between the wedge block and the inner wall of the central rotating shaft. An electric push rod, which pushes the frustums back and forth, is fixedly installed inside the central rotating shaft. The front end of the telescopic section of the electric push rod is fixedly connected to the frustum.

[0012] In one possible implementation, an annular groove is provided on the front side of the movable disk, the center of the annular groove coincides with the axis of the central rotating shaft, and a support rod is fixedly connected to the inner side of the movable disk. The support rod slides through the interior of the central rotating shaft and is then fixedly connected to the telescopic shaft of the electric push rod.

[0013] In one possible implementation, the expansion component two includes a movable block that is slidably mounted inside a movable ring. The movable block has two inclined grooves that are equidistantly distributed in the front and back. A sliding rod is slidably mounted inside the inclined groove along its length. Two sliding rods corresponding to the same movable block are fixedly connected to movable plates that are symmetrically distributed about the movable block. A horizontal plate is fixedly connected to one end of the two movable plates near the center of the circular groove. A linkage rod is fixedly connected to the rear side of the movable block. The rear end of the linkage rod slides through the rear of the movable ring and is slidably mounted in the annular groove.

[0014] In one possible implementation, the clamping assembly includes a second electric push rod fixedly mounted on the side of the horizontal plate near the center of the circular groove. The telescopic shaft of the second electric push rod is fixedly connected to a corresponding retaining plate. Telescopic rods symmetrically distributed about the front and rear of the second electric push rod are fixedly connected between the horizontal plate and the corresponding retaining plate.

[0015] In one possible implementation, the drive mechanism includes a drive disk one coaxially fixedly connected to the rear side of the central rotating shaft, a gear ring coaxially fixedly connected to the outer side of the movable ring, a drive motor fixedly mounted on the rear side of the housing, a transmission shaft located below the drive disk one fixedly connected to the front end of the output shaft of the drive motor, the transmission shaft being rotatably mounted inside the housing, a drive disk two and a drive gear coaxially fixedly connected to the outer side of the transmission shaft, the drive gear meshing with the gear ring, both drive disk one and drive disk two being single-sided bevel gears, a transmission wheel located between drive disk one and drive disk two being rotatably connected inside the housing, the transmission wheel being a double-sided bevel gear, drive disk one and drive disk two meshing with the upper and lower sides of the transmission wheel respectively, drive disk one and gear ring having the same number of teeth, drive gear, transmission wheel, and drive disk two having the same number of teeth, and the total transmission ratio from gear ring to drive gear being equal to the total transmission ratio from drive disk one to drive disk two.

[0016] In one possible implementation, the limiting mechanism includes a limiting plate fixedly connected to the rear side of the expansion plate. The limiting plate has a through groove running from front to back inside. A scale line is provided on the front side of the limiting plate. A limiting rod is slidably mounted on the front side of the limiting plate. An up-and-down adjustment assembly for driving the limiting rod to move up and down is installed on the limiting plate. A limiting assembly for limiting the expansion degree of the expansion plate is installed between the uppermost limiting plate and the movable disc. The up-and-down adjustment assembly includes a first sliding groove opened at the front end of the limiting plate and parallel to the scale line. A threaded rod is rotatably mounted inside the first sliding groove. The end of the threaded rod away from the center of the circular groove rotatably passes through to the outside of the limiting plate and is fixedly connected to a handwheel. A first slider is threadedly connected to the outer side of the threaded rod. The first slider is slidably mounted inside the first sliding groove. The rear side of the limiting rod is fixedly mounted on the front side of the first slider.

[0017] In one possible implementation, the limiting component includes a second scale line on the front side of the movable disk, a second slide groove parallel to the second scale line on the front side of the movable disk, a second slider slidably mounted inside the second slide groove, the second slider being fixed in the second slide groove by bolts, a baffle fixedly connected to the front side of the second slider, and a second protrusion fixedly connected to the top of the rear side of the uppermost limiting plate, the second protrusion being located below the baffle and the rear end of the second protrusion overlapping the front end of the baffle.

[0018] In one possible implementation, the guiding mechanism includes an arc-shaped rod rotatably mounted on the front end of the expanding plate, the concave surface of the arc-shaped rod facing the axis of the housing. A support assembly 1 for elastically supporting the arc-shaped rod rotatably is mounted on the side of the expanding plate near the center of the circular groove. The support assembly 1 includes a fixing plate 1 fixedly mounted on the side of the expanding plate near the center of the circular groove. A return spring 2 is fixedly connected between the fixing plate 1 and the arc-shaped rod rotatably mounted on the front end of the retaining plate, the concave surface of the arc-shaped rod rotatably facing away from the axis of the housing. A support assembly 2 is mounted on the side of the retaining plate away from the center of the circular groove. The support assembly 2 includes a fixing plate 2 fixedly connected to the side of the retaining plate away from the center of the circular groove. A return spring 3 is fixedly connected between the fixing plate 2 and the arc-shaped rod 2.

[0019] In one possible implementation, a processing mechanism is mounted on the housing; the processing mechanism includes a support ring located at the front of the housing and coaxial with the circular groove; electric push rods three for driving the support ring to move back and forth are symmetrically mounted on the left and right sides of the housing; the front end of the telescopic shaft of the electric push rods three is fixedly connected to the support ring; a plurality of electric heating blocks are evenly mounted circumferentially on the inner ring wall of the support ring; a cooling assembly is mounted on the outside of the support ring; the cooling assembly includes an annular tube fixedly mounted on the outer ring wall at the rear end of the support ring; a plurality of air outlets are evenly distributed circumferentially on the rear side of the annular tube; a cold air duct is fixedly mounted on the top of the support ring; the rear side of the cold air duct communicates with the annular tube; a plurality of external pressure plates are evenly mounted circumferentially on the rear side of the support ring; the external pressure plates are located on the side of the air outlets closer to the center of the support ring.

[0020] The beneficial effects of the present invention are as follows: 1. The expansion mechanism and the conforming mechanism of the present invention work together to expand the diameter of the plastic tube. When the expansion component pushes the expansion plate outward to expand the diameter of the plastic tube, the retaining plate can be clamped on the outer wall of the plastic tube and expand outward together with the expansion plate. In addition, the retaining plate rotates around the plastic tube in the circumference during the outward expansion process. By using the retaining plate to hold the outer wall of the plastic tube, it is possible to avoid the plastic tube from having uneven wall thickness and uneven outer wall.

[0021] 2. The expansion plate and the retaining plate of the present invention rotate at the same speed but in opposite directions. The expansion plate and the retaining plate act on the inner and outer walls of the plastic pipe respectively. The torsional forces generated when the expansion plate and the retaining plate rotate to expand the diameter cancel each other out, so as to avoid unidirectional torsional deformation of the pipe during the expansion process.

[0022] 3. The present invention limits the expansion plate and the retaining plate by setting a limiting mechanism. When the expansion component pushes the retaining plate to clamp the outer wall of the plastic pipe, the limiting rod blocks the retaining plate to avoid excessive clamping force of the retaining plate on the outer wall of the plastic pipe, which would damage the plastic pipe. At the same time, when the expansion plate and the retaining plate expand outward, the limiting component can limit the expansion degree of the expansion plate and the retaining plate, thereby improving the accuracy of the plastic pipe expansion. Attached Figure Description

[0023] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0024] Figure 2 This is a right-side sectional view of the present invention.

[0025] Figure 3 This is a partial cross-sectional view of the diameter expansion mechanism of the present invention.

[0026] Figure 4 This is a partial cross-sectional view of the conformal mechanism of the present invention.

[0027] Figure 5 This is a partial cross-sectional view of the clamping component of the present invention.

[0028] Figure 6 This is a three-dimensional structural diagram of the driving mechanism of the present invention.

[0029] Figure 7 This is a three-dimensional structural diagram of the limiting mechanism of the present invention.

[0030] Figure 8 This is a three-dimensional structural diagram of the up-and-down adjustment component of the present invention.

[0031] Figure 9 This is a three-dimensional structural diagram of the limiting component of the present invention.

[0032] Figure 10 This is a three-dimensional structural diagram of the cooling component of the present invention.

[0033] In the diagram: 1. Shell; 11. Circular groove; 2. Expansion mechanism; 21. Central shaft; 22. Expansion plate; 23. Expansion assembly one; 231. Frustum; 232. Expansion rod; 233. Wedge block; 234. Return spring one; 235. Electric push rod one; 24. Movable disc; 241. Annular groove; 3. Conformal mechanism; 31. Movable ring; 32. Holding plate; 321. Protrusion one; 33. Expansion assembly two; 331. Movable block; 332. Inclined groove; 333. Slide rod; 334. Movable plate; 335. Horizontal plate; 336. Linkage rod; 34. Clamping assembly; 341. Electric push rod two; 342. Telescopic rod; 4. Drive mechanism; 41. Drive disc one; 42. Gear ring; 43. Drive motor; 44. Transmission shaft; 45. Drive disc two; 46. Drive gear; 47. Transmission 5. Wheel; 5. Limiting mechanism; 51. Limiting plate; 511. Through groove; 52. Scale line one; 53. Limiting rod; 54. Up and down adjustment assembly; 541. First slide groove; 542. Threaded rod; 543. First slider; 55. Limiting assembly; 551. Scale line two; 552. Second slide groove; 553. Second slider; 554. Baffle; 555. Protrusion two; 6. Guiding mechanism; 61. Arc rod one; 62. Support assembly one; 621. Fixing plate one; 622. Return spring two; 63. Arc rod two; 64. Support assembly two; 641. Fixing plate two; 642. Return spring three; 7. Processing mechanism; 71. Support ring; 72. Electric push rod three; 73. Electric heating block; 74. Cooling assembly; 741. Ring tube; 742. Air outlet; 743. Cold air duct; 75. External pressure plate. Detailed Implementation

[0034] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be implemented in many other ways different from those described below, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0035] Please see Figure 1 and Figure 2 A plastic pipe online diameter expansion device includes a housing 1 and a circular groove 11 formed on the front side of the housing 1. A diameter expansion mechanism 2 is installed at the center of the circular groove 11. A conformal mechanism 3 is installed on the inner ring wall of the circular groove 11. A drive mechanism 4 is installed on the housing 1 to drive the diameter expansion mechanism 2 and the conformal mechanism 3 to rotate in opposite directions. A limit mechanism 5 is installed on the diameter expansion mechanism 2. A guide mechanism 6 is installed between the diameter expansion mechanism 2 and the conformal mechanism 3. A processing mechanism 7 is installed on the housing 1.

[0036] Please see Figure 1 , Figure 2 and Figure 3 The diameter expansion mechanism 2 includes a central rotating shaft 21 rotatably installed inside the housing 1 and coaxial with the circular groove 11. Several diameter expansion plates 22 are evenly distributed on the outer circumference of the central rotating shaft 21. An expansion component 23 is installed on the central rotating shaft 21 to push the diameter expansion plates 22 to expand outward. A movable disc 24 located behind the diameter expansion plates 22 is slidably sleeved on the outer side of the central rotating shaft 21.

[0037] Please see Figure 2 , Figure 4 , Figure 5 and Figure 6 The conformal mechanism 3 includes a movable ring 31 rotatably mounted on the inner ring wall of the circular groove 11. A plurality of retaining plates 32 are evenly distributed on the inner circumference of the movable ring 31. A protrusion 321 is fixedly connected to the rear side of the retaining plate 32. A plurality of expansion components 33 are evenly mounted on the movable ring 31 to drive the corresponding retaining plate 32 to expand outward. A clamping component 34 is mounted on the expansion component 33 to drive the corresponding retaining plate 32 to clamp inward.

[0038] It should be noted that both the housing 1 and the movable ring 31 are detachable assembly structures to facilitate the assembly of internal components. Furthermore, the specific detachable assembly method can be reasonably adjusted according to actual production needs and is not limited to the following: Figure 1 and Figure 4 As shown.

[0039] Please see Figure 3 The expansion assembly 23 includes two frustums 231 that are slidably installed inside the central rotating shaft 21 and connected end to end. The cross-sectional area of ​​the frustums 231 gradually increases from front to back. An expansion plate 22 is fixedly connected to an expansion rod 232 that is symmetrically distributed front to back on one side near the central rotating shaft 21. The end of the expansion rod 232 that is close to the center of the central rotating shaft 21 slides through the interior of the central rotating shaft 21 and is fixedly connected to a wedge block 233. The inclined surface of the wedge block 233 slides and engages with the inclined surface of the corresponding frustum 231. A return spring 234 that is sleeved on the outside of the expansion rod 232 is fixedly connected between the wedge block 233 and the inner wall of the central rotating shaft 21. An electric push rod 235 that pushes the frustums 231 to move back and forth is fixedly installed inside the central rotating shaft 21. The front end of the telescopic section of the electric push rod 235 is fixedly connected to the adjacent frustum 231.

[0040] The electric push rod 235 pushes the frustum 231 forward, and the frustum 231 pushes the wedge block 233 and the expansion rod 232 to move away from the center of the central axis 21. At this time, the return spring 234 is compressed by the wedge block 233. Then the expansion rod 232 pushes the expansion plate 22 to expand outward, so that the diameter of the plastic tube gradually increases. When the electric push rod 235 drives the frustum 231 to move backward, the rebound force of the wedge block 233 pushes the wedge block 233 to move closer to the center of the central axis 21. Then the wedge block 233 drives the expansion rod 232 and the expansion plate 22 to contract inward, releasing the expansion support of the plastic tube.

[0041] Please see Figure 3 An annular groove 241 is provided on the front side of the movable disc 24. The center of the annular groove 241 coincides with the axis of the central rotating shaft 21. A support rod is fixedly connected to the inner side of the movable disc 24. The support rod slides through the interior of the central rotating shaft 21 and is fixedly connected to the telescopic shaft of the electric push rod 235.

[0042] Please see Figure 2 , Figure 3 , Figure 4 and Figure 5 The expansion component 2 33 includes a movable block 331 that is slidably installed inside the movable ring 31. The movable block 331 has two inclined grooves 332 that are equidistantly distributed in the front and back. A sliding rod 333 is slidably installed inside the inclined groove 332 along its length. The two sliding rods 333 corresponding to the same movable block 331 are fixedly connected to movable plates 334 that are symmetrically distributed about the movable block 331. The two movable plates 334 are slidably connected to a horizontal plate 335 after one end near the center of the circular groove 11 slides through to the inside of the movable ring 31. A linkage rod 336 is fixedly connected to the rear side of the movable block 331. The rear end of the linkage rod 336 slides through to the rear of the movable ring 31 and is slidably installed in the annular groove 241. The inclination angle of the inclined groove 332 is the same as the inclination angle of the inclined surface on the corresponding side of the frustum 231.

[0043] When the electric push rod 235 pushes the frustum 231 forward, the electric push rod 235 will push the movable disk 24 forward synchronously. Then, the movable disk 24 will push the linkage rod 336 and the movable block 331 forward. During the forward movement of the movable block 331, the inclined groove 332 can push the slide rod 333 to move away from the center of the circular groove 11. Then, the slide rod 333 will drive the movable plate 334 and the horizontal plate 335 to move away from the center of the circular groove 11. After that, the horizontal plate 335 will drive the clamping assembly 34 and the retaining plate 32 to move away from the center of the circular groove 11, so that the retaining plate 32 and the corresponding expansion plate 22 expand outward synchronously at the same speed. The retaining plate 32 and the expansion plate 22 will spin and shape the plastic tube from both the inside and outside, so as to avoid uneven wall thickness and uneven outer wall of the plastic tube during the expansion process.

[0044] Please see Figure 4 and Figure 5 The clamping assembly 34 includes an electric push rod 341 fixedly installed on the side of the horizontal plate 335 near the center of the circular groove 11. The telescopic shaft of the electric push rod 341 is fixedly connected to the corresponding retaining plate 32. The horizontal plate 335 and the corresponding retaining plate 32 are fixedly connected to telescopic rods 342 that are symmetrically distributed about the front and rear of the electric push rod 341.

[0045] The retaining plate 32 is moved closer to the center of the circular groove 11 by the electric push rod 341, so that the retaining plate 32 can be clamped on the outer wall of the plastic tube. The telescopic rod 342 can play a guiding role and improve the stability of the retaining plate 32 when it moves.

[0046] Please see Figure 2 , Figure 4 , Figure 6 and Figure 7The drive mechanism 4 includes a drive disk 41 coaxially fixedly connected to the rear side of the central rotating shaft 21, a gear ring 42 coaxially fixedly connected to the outer side of the movable ring 31, a drive motor 43 fixedly mounted on the rear side of the housing 1, a transmission shaft 44 located below the drive disk 41 fixedly connected to the front end of the output shaft of the drive motor 43, the transmission shaft 44 being rotatably mounted inside the housing 1, a drive disk 45 and a drive gear 46 coaxially fixedly connected to the outer side of the transmission shaft 44, the drive gear 46 meshing with the gear ring 42, both drive disk 41 and drive disk 45 being single-sided bevel gears, and the inner side of the housing 1... The part is rotatably connected to a transmission wheel 47 located between drive disc 1 41 and drive disc 2 45. The transmission wheel 47 is a double-sided bevel gear. Drive disc 1 41 and drive disc 2 45 mesh with the upper and lower surfaces of the transmission wheel 47, respectively. Drive disc 1 41 and gear ring 42 have the same number of teeth. Drive gear 46, transmission wheel 47 and drive disc 2 45 have the same number of teeth. The diameters of drive disc 1 41 and gear ring 42 are larger than the diameters of drive gear 46, transmission wheel 47 and drive disc 2 45. That is, the total transmission ratio from gear ring 42 to drive gear 46 is equal to the total transmission ratio from drive disc 1 41 to drive disc 2 45.

[0047] When expanding the diameter of the plastic tube, the drive motor 43 drives the transmission shaft 44 to rotate clockwise. Then, the transmission shaft 44 drives the second drive disk 45 and the drive gear 46 to rotate synchronously. After that, the second drive disk 45 drives the transmission wheel 47 to rotate. The rotation axis of the second drive disk 45 and the rotation axis of the transmission wheel 47 are perpendicular to each other in the vertical plane. The rotation of the transmission wheel 47 will drive the first drive disk 41 to rotate clockwise, so that the central shaft 21 rotates clockwise during the expansion process. When the central shaft 21 rotates clockwise, the drive gear 46 drives the gear ring 42 to rotate counterclockwise. Then, the gear ring 42 drives the movable ring 31 to rotate counterclockwise. This allows the expansion plate 22 and the retaining plate 32 to rotate in opposite directions during the expansion process, avoiding unidirectional torsion of the plastic tube.

[0048] Please see Figure 2 , Figure 3 , Figure 5 , Figure 7 and Figure 8 The limiting mechanism 5 includes a limiting plate 51 fixedly connected to the rear side of the expansion plate 22. The limiting plate 51 has a through groove 511 that runs through the front and back. The front side of the limiting plate 51 has a scale line 52. A limiting rod 53 is slidably installed on the front side of the limiting plate 51. An up-and-down adjustment component 54 that drives the limiting rod 53 to move up and down is installed on the limiting plate 51. A limiting component 55 that limits the expansion degree of the expansion plate 22 is installed between the uppermost limiting plate 51 and the movable disc 24.

[0049] Based on the wall thickness of the plastic tube before expansion, the limiting rod 53 is moved to the same value as the wall thickness of the plastic tube on the scale line 52. When the retaining plate 32 moves inward to clamp the plastic tube before heating, the limiting rod 53 blocks the protrusion 321 to control the degree of downward clamping of the retaining plate 32, so as to avoid damage to the plastic tube due to excessive clamping force of the retaining plate 32.

[0050] Please see Figure 7 and Figure 8 The up-down adjustment component 54 includes a first slide groove 541 opened at the front end of the limiting plate 51 and parallel to the scale line 52. A threaded rod 542 is rotatably installed inside the first slide groove 541. One end of the threaded rod 542 away from the center of the circular groove 11 is rotatably passed through to the outside of the limiting plate 51 and then fixedly connected to a handwheel. A first slider 543 is threadedly connected to the outside of the threaded rod 542. The first slider 543 is slidably installed inside the first slide groove 541. The rear side of the limiting rod 53 is fixedly installed on the front side of the first slider 543.

[0051] By rotating the handwheel, the threaded rod 542 is driven to rotate, and then the threaded rod 542 drives the first slider 543 to move up and down along the first slide groove 541. After that, the first slider 543 drives the limiting rod 53 to move up and down, which can adjust the distance between the limiting rod 53 and the expansion plate 22.

[0052] Please see Figure 7 , Figure 8 and Figure 9 The limiting component 55 includes a scale line 551 on the front side of the movable disc 24. A second slide groove 552 parallel to the scale line 551 is opened on the front side of the movable disc 24. A second slider 553 is slidably installed inside the second slide groove 552. The second slider 553 is fixed in the second slide groove 552 by bolts. A baffle 554 is fixedly connected to the front side of the second slider 553. A protrusion 555 is fixedly connected to the top of the rear side of the uppermost limiting plate 51. The protrusion 555 is located below the baffle 554 and the rear end of the protrusion 555 overlaps with the front end of the baffle 554.

[0053] Before expanding the diameter of the plastic tube, the diameter to be expanded is indicated by the second scale line 551. Then, the height of the baffle 554 is adjusted by sliding the second slider 553 up and down. The baffle 554 is moved to the indicated value. Then, the bolt is tightened to fix the second slider 553. When the expanding plate 22 and the retaining plate 32 expand outward, the baffle 554 blocks the protrusion 555, which can limit the degree of expansion of the expanding plate 22 and improve the accuracy of expanding the diameter of the plastic tube.

[0054] Please see Figure 2 , Figure 5 and Figure 8The guiding mechanism 6 includes an arc-shaped rod 61 rotatably mounted on the front end of the expansion plate 22, with the concave surface of the arc-shaped rod 61 facing the axis of the housing 1. A support assembly 62 is installed on the side of the expansion plate 22 near the center of the circular groove 11 to provide elastic support for the arc-shaped rod 61. The support assembly 62 includes a fixing plate 621 fixedly mounted on the side of the expansion plate 22 near the center of the circular groove 11. A return spring 622 is fixedly connected between the fixing plate 621 and the arc-shaped rod 61. An arc-shaped rod 63 is rotatably mounted on the front end of the retaining plate 32, with the concave surface of the arc-shaped rod 63 facing away from the axis of the housing 1. A support assembly 64 is installed on the side of the retaining plate 32 away from the center of the circular groove 11. The support assembly 64 includes a fixing plate 641 fixedly connected to the side of the retaining plate 32 away from the center of the circular groove 11. A return spring 642 is fixedly connected between the fixing plate 641 and the arc-shaped rod 63.

[0055] Before expanding the diameter of the plastic tube, arc-shaped rod 1 61 and arc-shaped rod 2 63 are pressed tightly on the inner and outer sides of the connection between the section to be expanded and the section not to be expanded. The return spring 2 622 and return spring 3 642 provide elastic support for arc-shaped rod 1 61 and arc-shaped rod 2 63 respectively. During expansion, arc-shaped rod 1 61 and arc-shaped rod 2 63 can guide the inner and outer sides of the plastic tube to shape, so that the connection gradually expands outward in an arc-shaped structure, which helps to improve the uniformity of the wall thickness at the connection.

[0056] Please see Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 8 and Figure 10 The processing mechanism 7 includes a support ring 71 located in front of the housing 1 and coaxial with the circular groove 11. Electric push rods 72 that drive the support ring 71 to move back and forth are symmetrically installed on the left and right sides of the housing 1. The front end of the telescopic shaft of the electric push rods 72 is fixedly connected to the support ring 71. Several electric heating blocks 73 are evenly installed circumferentially on the inner ring wall of the support ring 71. A cooling assembly 74 is installed on the outside of the support ring 71. The cooling assembly 74 includes an annular pipe 741 fixedly installed on the outer ring wall of the rear end of the support ring 71. Several air outlets 742 are evenly distributed circumferentially on the rear side of the annular pipe 741. A cold air pipe 743 is fixedly installed on the top of the support ring 71. The rear side of the cold air pipe 743 is connected to the annular pipe 741. The top end of the cold air pipe 743 is connected to an external air cooler. Several external pressure plates 75 are evenly installed circumferentially on the rear side of the support ring 71. The external pressure plates 75 are located on the side of the air outlets 742 close to the center of the support ring 71.

[0057] Initially, the expansion plate 22 and the retaining plate 32 are separated from the inner and outer walls of the plastic tube. When the expansion plate 22 provides internal support to the plastic tube, the electric push rod 72 drives the support ring 71 to move backward, causing the outer pressure plate 75 to move to the outside of the expansion plate 22 and adhere to the outer wall of the plastic tube. Then, the expansion assembly 23 pushes the expansion plate 22 to expand outward until it contacts the inner wall of the plastic tube. At this time, the outer pressure plate 75 can support and restrict the outer wall of the plastic tube, so that the expansion plate 22 is accurately supported on the inner wall of the plastic tube, avoiding excessive expansion of the expansion plate 22 which could damage the plastic tube.

[0058] After the inner support is completed, the electric push rod 72 drives the support ring 71 to continue to move backward, so that the support ring 71 moves to the outside of the expansion plate 22. At this time, the outer pressure plate 75 moves through the through groove 511 to the right side of the expansion plate 22. Then, the electric heating block 73 is used to heat and soften the plastic tube appropriately. After the plastic tube is softened, the electric push rod 72 drives the support ring 71 to move forward away from the circular groove 11. Then, the clamping assembly 34 pushes the retaining plate 32 to move inward to clamp the outer wall of the plastic tube.

[0059] After the plastic tube is expanded and the expanding plate 22 and retaining plate 32 are still in contact with the expanded section, cold air is supplied to the annular pipe 741 through the cold air pipe 743. Then, the air outlet 742 blows the cold air toward the expanded section of the plastic tube, so that the plastic tube is cooled and shaped. This prevents the diameter of the expanded section of the plastic tube from shrinking and deforming when the expanding plate 22 and retaining plate 32 loosen their support for the plastic tube.

[0060] Please see Figures 1-10 In specific use, in step one, the initial state, both electric push rod 235 and electric push rod 341 are in the retracted state, so that there is enough space between the expansion plate 22 and the retaining plate 32 for the plastic tube and the cooling component 74 to pass through. By rotating the handwheel, the threaded rod 542 is rotated, so that the first slider 543 drives the limiting rod 53 to move up and down. The scale line 52 indicates the distance between the limiting rod 53 and the expansion plate 22, so that the limiting rod 53 moves to a position with the same value as the wall thickness of the plastic tube. Then, the baffle 554 is moved up and down. The scale line 551 indicates the distance from the baffle 554 to the center of the movable disc 24, so that the baffle 554 moves to a vertical position with the same diameter as the expanded plastic tube. Then, the bolt is tightened to fix the second slider 553.

[0061] Step 2: The plastic tube is clamped and moved backward by an external clamping and feeding mechanism, so that the rear end of the plastic tube enters the interior of the circular groove 11 and abuts against the limiting plate 51. The axis of the plastic tube always coincides with the axis of the circular groove 11. At this time, the expansion plate 22 is inside the plastic tube. Then, the electric push rod 72 drives the support ring 71 to move backward a certain distance, so that the outer pressure plate 75 moves to the outside of the expansion plate 22 and fits against the outside of the plastic tube.

[0062] Step 3: The electric push rod 235 pushes the frustum 231 forward, and then the frustum 231 pushes the wedge block 233 and the expansion rod 232 to move away from the center of the central axis 21, so that the expansion rod 232 pushes the corresponding expansion plate 22 to expand outward until the expansion plate 22 is supported on the inner wall of the plastic tube. The outer pressure plate 75 can limit the expansion degree of the expansion plate 22 on the outside of the plastic tube, so that the expansion plate 22 is accurately supported on the inner wall of the plastic tube, and avoids the expansion degree of the expansion plate 22 being too large, which would damage the plastic tube.

[0063] Step 4: Drive the support ring 71 to continue moving backward by the electric push rod 72, so that the electric heating block 73 moves to the outside of the expansion section of the plastic tube. At this time, the outer pressure plate 75 passes through the through groove 511 and moves to the rear side of the expansion plate 22. Then, the electric heating block 73 heats and softens the expansion section of the plastic tube. After softening, the electric push rod 72 pushes the support ring 71 to move forward, so that the support ring 71 and the outer pressure plate 75 are completely moved to the outside of the circular groove 11.

[0064] Step 5: The retaining plate 32 is moved closer to the center of the circular groove 11 by the electric push rod 2 341, so that the retaining plate 32 is clamped on the outer wall of the plastic pipe. When the retaining plate 32 is clamped on the outer wall of the plastic pipe, the protrusion 1 321 just abuts against the limiting rod 53. The limiting rod 53 can prevent the protrusion 1 321 and the retaining plate 32 from moving further, thus limiting the clamping degree of the retaining plate 32 and preventing the retaining plate 32 from being clamped too much.

[0065] Step Six: Drive motor 43 drives transmission shaft 44 to rotate clockwise. Then, transmission shaft 44 drives drive disc 2 45 and drive gear 46 to rotate. Drive disc 2 45 drives drive disc 1 41 and central shaft 21 to rotate clockwise via belt, so that expansion plate 22 rotates clockwise against the inner wall of plastic tube. At the same time, drive gear 46 drives gear ring 42 and movable ring 31 to rotate counterclockwise, so that retaining plate 32 rotates counterclockwise against the outer wall of plastic tube. The retaining plate 32 and expansion plate 22 rotate at the same speed but in opposite directions. The torsional forces generated by the rotation of retaining plate 32 and expansion plate 22 cancel each other out, preventing the plastic tube from tortuous deformation during the expansion process.

[0066] Step 7: During the rotation of the expanding plate 22 and the retaining plate 32, the electric push rod 235 pushes the frustum 231 and the movable disk 24 forward, causing the expanding plate 22 to gradually expand and the diameter of the plastic tube to gradually increase. When the movable disk 24 moves forward, it pushes the linkage rod 336 forward, and then the linkage rod 336 pushes the movable block 331 forward, causing the inclined groove 332 to push the slide rod 333 to move away from the center of the circular groove 11. Then the slide rod 333 pushes the movable plate 334 and the horizontal plate 335 to move away from the center of the circular groove 11. Then the horizontal plate 335 drives the electric push rod 341 and the retaining plate 32 to expand outward synchronously at the same speed as the expanding plate 22. The retaining plate 32 is used to rotate and plasticize the outer wall of the plastic tube to avoid uneven wall thickness and uneven outer wall of the plastic tube.

[0067] Step 8: When the expansion plate 22 expands the diameter of the plastic tube to the required diameter, the second protrusion 555 moves outward to contact the baffle 554. At this time, the expansion plate 22 can no longer move outward, improving the accuracy of the plastic tube expansion. After the expansion is completed, the electric push rod 235 stops pushing the frustum 231 and the movable disc 24 forward. Then, the external cold air fan delivers cold air to the cold air pipe 743. After that, the cold air pipe 743 delivers the cold air to the annular pipe 741. Then, the air outlet 742 blows the cold air towards the expansion section of the plastic tube, so that the plastic tube cools and sets.

[0068] Step 9: After the diameter expansion is completed, the electric push rod 241 drives the retaining plate 32 to move away from the center of the circular groove 11, so that the retaining plate 32 leaves the outer surface of the plastic tube. Then, the electric push rod 235 drives the frustum 231 to move backward. Then, the return force of the return spring 234 pushes the wedge block 233 to move closer to the center of the central rotating shaft 21. Then, the wedge block 233 drives the expansion rod 232 and the diameter expansion plate 22 to contract inward, so that the diameter expansion plate 22 leaves the inner surface of the plastic tube. Finally, the expanded plastic tube is moved forward.

[0069] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "connected," "installed," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, an integral connection, or a sliding connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0070] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made based on the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A plastic pipe on-line expanding device, comprising a shell and a circular groove opened in the front side of the shell, characterized in that: The center of the circular groove is provided with a diameter expansion mechanism, the inner ring wall of the circular groove is provided with a shape preserving mechanism, and the shell is provided with a driving mechanism; The diameter expansion mechanism comprises a central rotating shaft which is rotatably installed inside the shell and coaxial with the circular groove, a plurality of diameter expansion plates are uniformly distributed on the outer periphery of the central rotating shaft, an expansion assembly one is installed on the central rotating shaft, and an active disc is slidably sleeved on the outer side of the central rotating shaft and located at the rear side of the diameter expansion plate; The shape preserving mechanism comprises an active ring which is rotatably installed on the inner ring wall of the circular groove, a plurality of retaining plates are uniformly distributed on the inner side of the active ring, a plurality of expansion assemblies two are uniformly installed on the active ring to drive the corresponding retaining plates to expand outward, and a clamping assembly is installed on the expansion assembly two to drive the retaining plates to clamp inward. When the diameter expansion plates are pushed outward by the expansion assembly one to expand the diameter of the plastic pipe, the retaining plates clamp the outer wall of the plastic pipe and move synchronously with the diameter expansion plates, and the diameter expansion plates and the retaining plates rotate around the plastic pipe at the same speed and in opposite directions at the same time through the driving mechanism; A limiting mechanism is installed on the diameter expansion mechanism to limit the movement distance of the diameter expansion plates and the retaining plates; A guide mechanism is installed between the diameter expansion mechanism and the shape preserving mechanism to guide the shaping of the plastic pipe on both sides.

2. The device according to claim 1, characterized in that: The expansion assembly one comprises two prisms which are slidably installed in the central rotating shaft and connected end to end, the side of the diameter expansion plate close to the central rotating shaft is fixedly connected with expansion rods which are symmetrically distributed in front and back, one end of the expansion rod close to the center of the central rotating shaft is slidably penetrated into the interior of the central rotating shaft and then fixedly connected with a wedge block, the inclined surface of the wedge block is slidably matched with the inclined surface of the corresponding prism, a reset spring one is fixedly connected between the wedge block and the inner wall of the central rotating shaft and sleeved on the outside of the expansion rod, and an electric push rod one is fixedly installed in the interior of the central rotating shaft to push the prisms to move forward and backward, and the front end of the telescopic section of the electric push rod one is fixedly connected with the prism.

3. The apparatus according to claim 2, wherein: The front side of the active disc is provided with an annular groove, the center of the annular groove coincides with the axis of the central rotating shaft, the inner side of the active disc is fixedly connected with a support rod, and the support rod is slidably penetrated into the interior of the central rotating shaft and then fixedly connected with the telescopic shaft of the electric push rod one.

4. The apparatus according to claim 3, wherein: The expansion assembly two comprises a movable block which is slidably installed in the active ring, two inclined grooves which are equidistantly distributed in front and back are formed in the interior of the movable block, a slide rod is slidably installed in the interior of the inclined groove along the length direction of the inclined groove, two movable plates which are symmetrically distributed with respect to the movable block are fixedly connected between the two slide rods corresponding to the same movable block, one end of the corresponding two movable plates close to the center of the circular groove is fixedly connected with a horizontal plate, a linkage rod is fixedly connected to the rear side of the movable block, and the rear end of the linkage rod is slidably penetrated to the rear of the active ring and then slidably installed in the annular groove.

5. The apparatus according to claim 4, wherein: The clamping assembly comprises an electric push rod two which is fixedly installed on the side of the horizontal plate close to the center of the circular groove, the telescopic shaft of the electric push rod two is fixedly connected with the corresponding retaining plate, and the horizontal plate and the corresponding retaining plate are fixedly connected with telescopic rods which are symmetrically distributed in front and back with respect to the electric push rod two.

6. The apparatus for on-line expanding plastic pipes according to claim 1, characterized in that: The driving mechanism comprises a driving disc I coaxially and fixedly connected to the rear side of the central rotating shaft, a gear ring coaxially and fixedly connected to the outer side of the movable ring, a driving motor fixedly installed at the rear side of the shell, a transmission shaft fixedly connected to the front end of the output shaft of the driving motor and located below the driving disc I, the transmission shaft being rotatably installed in the shell, a driving disc II and a driving gear coaxially and fixedly connected to the outer side of the transmission shaft, the driving gear being engaged with the gear ring, the driving disc I and the driving disc II being single-sided bevel gears, a transmission wheel rotatably connected to the inside of the shell and located between the driving disc I and the driving disc II, the transmission wheel being a double-sided bevel gear, the driving disc I and the driving disc II being engaged with the upper and lower surfaces of the transmission wheel respectively, the gear ring having the same number of teeth as the driving disc I, the driving gear, the transmission wheel and the driving disc II having the same number of teeth, and the total transmission ratio from the gear ring to the driving gear being equal to the total transmission ratio from the driving disc I to the driving disc II.

7. The apparatus according to claim 1, wherein: The limiting mechanism comprises a limiting plate fixedly connected to the rear side of the diameter expansion plate, a through groove penetrating through the limiting plate from front to back, a scale line I arranged on the front side of the limiting plate, a limiting rod slidably installed on the front side of the limiting plate, an up-down adjusting assembly installed on the limiting plate and used for driving the limiting rod to move up and down, a limiting assembly installed between the uppermost limiting plate and the movable disc and used for limiting the expansion degree of the diameter expansion plate, the up-down adjusting assembly comprising a first sliding groove parallel to the scale line I and arranged on the front end of the limiting plate, a threaded rod rotatably installed in the first sliding groove, a hand wheel fixedly connected to the end of the threaded rod away from the center of the circular groove and rotatably penetrating through the limiting plate to the outside of the limiting plate, a first sliding block threadedly connected to the outer side of the threaded rod and slidably installed in the first sliding groove, and the limiting rod being fixedly installed on the front side of the first sliding block.

8. The apparatus according to claim 7, wherein: The limiting assembly comprises a scale line II arranged on the front side of the movable disc, a second sliding groove parallel to the scale line II and arranged on the front side of the movable disc, a second sliding block slidably installed in the second sliding groove, the second sliding block being fixed in the second sliding groove through bolts, and a baffle fixedly connected to the front side of the second sliding block. The top of the rear side of the uppermost limiting plate is fixedly connected with a second protrusion, the second protrusion is located below the baffle, and the rear end of the second protrusion and the front end of the baffle overlap with each other.

9. The apparatus of claim 1, wherein: The guiding mechanism comprises an arc-shaped rod I rotatably installed at the front end of the diameter expansion plate, the inner concave surface of the arc-shaped rod I facing the axis of the shell, a supporting assembly I installed on the side of the diameter expansion plate close to the center of the circular groove and used for elastically supporting the arc-shaped rod I, the supporting assembly I comprising a first fixed plate fixedly installed on the side of the diameter expansion plate close to the center of the circular groove, a second reset spring fixedly connected between the first fixed plate and the arc-shaped rod I, an arc-shaped rod II rotatably installed at the front end of the retaining plate, the inner concave surface of the arc-shaped rod II facing away from the axis of the shell, and a supporting assembly II installed on the side of the retaining plate away from the center of the circular groove, the supporting assembly II comprising a second fixed plate fixedly connected to the side of the retaining plate away from the center of the circular groove, and a third reset spring fixedly connected between the second fixed plate and the arc-shaped rod II.

10. The apparatus of claim 1, wherein: A processing mechanism is mounted on the shell; the processing mechanism includes a support ring coaxial with the circular groove in front of the shell, and symmetrical electric push rods three are mounted on the left and right sides of the shell to drive the front and back movement of the support ring, the front end of the telescopic shaft of the electric push rod three is fixedly connected with the support ring, a plurality of electric heating blocks are uniformly installed on the inner ring wall of the support ring, a cooling assembly is installed outside the support ring, the cooling assembly includes an annular pipe fixedly installed on the outer ring wall of the rear end of the support ring, a plurality of air outlets are uniformly distributed on the rear side of the annular pipe, a cold air pipe is fixedly installed on the top of the support ring, the rear side of the cold air pipe is communicated with the annular pipe, and a plurality of outer pressing plates are uniformly installed on the rear side of the support ring, and the outer pressing plates are located on the side of the air outlet close to the center of the support ring.

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