Internal thread rapid demolding injection molding device

Abstract

The utility model relates to the technical field of injection molding equipment, in particular to an internal thread rapid demolding injection molding device, which is characterized by comprising a fixed mold assembly, a movable mold assembly and a connecting rod, cavities for injection molding are formed in the fixed mold assembly and the movable mold assembly, a core rod is rotatably mounted in the cavity of the movable mold assembly, and a plurality of threaded surfaces and smooth parts which are mutually spaced are arranged on the outer wall surface of the core rod. According to the utility model, the threaded surface and the smooth part are arranged on the core rod, so that the core rod can be directly pulled out from a product only by rotating the smooth part to the position of the original threaded surface during demolding, and the demolding efficiency of the product is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of injection molding equipment, and more specifically, to an injection molding device for rapid demolding of internal threads. Background Art

[0002] With the continuous progress of modern industrial technology, plastic products have been widely used in various fields due to their light weight, corrosion resistance, easy processing and other characteristics. Among them, PVC (polyvinyl chloride), as a common thermoplastic, occupies an important position in the field of injection molding due to its good physical properties and processing performance. The internal thread structure is applied to a variety of common injection molded products, and its production efficiency is much lower than that of other straight-through, elbow-like products and external thread structure products. The main reason is that the demolding of the internal thread structure cannot directly force the extraction of the thread mandrel assembly. It is necessary to use a motor to drive the mandrel assembly to rotate, so that the threads on the mandrel assembly gradually screw out along the internal thread helix of the injection molding to achieve the purpose of demolding. The whole process takes a long time and accounts for too large a proportion in the injection molding cycle, seriously affecting the injection molding efficiency of products with internal thread structures.

[0003] There is a Chinese invention with a publication number of CN115139447A, which discloses an injection molding device for an internal thread insert on the appearance surface of an injection molded part. It includes an injection molding die assembly. The injection molding die assembly includes an insert die for shaping the insert surface of the injection molded part, and also includes a flash stopper. The flash stopper includes a positioning post and a screwing post for screwing the internal thread insert. The insert die includes a positioning hole, and the positioning post is in transitional fit with the positioning hole. The insert die is also provided with a magnetic attraction assembly for magnetically attracting the flash stopper, so that the outer surface of the internal thread insert fits against the inner wall of the insert die. The present invention can avoid the problems of flash overflow in the hole of the internal thread insert and surface encapsulation, and moreover, the surface of the internal thread insert after injection molding can be flush with the plastic appearance surface where it is located.

[0004] In the above technical solution, since the internal thread insert forms a threaded connection with the product, when demolding the internal thread insert and the product, it is necessary to continuously rotate the internal thread insert or the product until the internal thread insert is screwed out of the product. A large amount of time is consumed in this process, reducing the production efficiency of the product. Summary of the Utility Model

[0005] To solve the above technical problems, the utility model provides an injection molding device for rapid demolding of internal threads. By providing a threaded surface and a smooth part on the mandrel, when demolding, only need to rotate the smooth part to the position where the original threaded surface is located, and the mandrel can be directly withdrawn from the product, improving the demolding efficiency of the product.

[0006] In order to solve the above technical problems, the technical solution adopted by the utility model is: an internal thread quick demolding injection molding device, including a fixed mold assembly, a movable mold assembly and a connecting piece, the movable mold assembly is slidably connected to the fixed mold assembly through the connecting piece, and a cavity for injection molding is provided in the fixed mold assembly and the movable mold assembly, a core rod is rotatably installed in the cavity of the movable mold assembly, and a plurality of threaded surfaces and smooth portions are alternately provided on the outer wall surface of the core rod, and a retraction device is also included, and the retraction device is connected to the smooth portion to drive the smooth portion to move toward the inside of the core rod.

[0007] In this technical solution, when producing internal threaded pipe fittings, first the movable mold assembly and the fixed mold assembly are molded together, and both the movable mold assembly and the fixed mold assembly are slidably connected to the connecting piece. The movable mold assembly and the fixed mold assembly can only move along the length direction of the connecting piece. The connecting piece ensures that the relative position of the movable mold assembly and the fixed mold assembly is accurate after the mold is closed, and the shape of the pipe fitting after injection molding will not be deformed due to the deviation of the relative position of the movable mold assembly and the fixed mold assembly. The movable mold assembly and the fixed mold assembly are provided with a cavity. After the mold is closed, the core rod is inserted into the cavity. The cavity forms a closed space. The cavity determines the external shape of the pipe fitting, and the core rod determines the internal shape of the pipe fitting. A threaded surface is provided on the core rod, so that a thread matching the threaded surface will also be generated inside the pipe fitting after injection molding. An injection port is provided on the fixed mold assembly, and the injection port is connected to the cavity. The injection molding raw material is injected into the cavity through the injection port to fill the space between the cavity and the core rod. After the injection molding raw material cools and solidifies, a pipe fitting product is formed, and then the fixed mold component is separated from the movable mold component, and the cavity changes from closed to open, and the product can be directly taken out of the cavity. When taking out the pipe fitting product, since the pipe fitting has threads formed by injection molding, and the core rod is also provided with a threaded surface, the two form a threaded connection. When taking out the pipe fitting product, the threaded connection between the two needs to be released first. There are multiple threaded surfaces evenly distributed on the outer wall surface of the core rod, and smooth parts are provided between each threaded surface. During injection molding, the inside of the pipe fitting product will only form threads on the threaded surface of the core rod, and a smooth inner wall surface is formed at the smooth part. Since there are multiple threaded surfaces and they are evenly distributed on the outer wall surface of the core rod, the threads formed in the pipe fitting are also evenly distributed on the inner wall surface of the pipe fitting. During use, the pipe fitting product can also form a uniform threaded connection with other components along the circumferential direction without affecting the connection effect. When demoulding the pipe fitting product and the mandrel, you only need to rotate the mandrel and rotate the threaded surface of the mandrel to the smooth inner wall surface of the pipe fitting product, so that the threaded connection between the mandrel and the pipe fitting product is released, so that the mandrel can be directly pulled out of the pipe fitting product, greatly improving the demoulding efficiency of the mandrel. Since the inner wall surface of the pipe fitting product only fits the outer wall surface of the mandrel during injection molding, when the mandrel rotates, the internal thread on the pipe fitting product will conflict with the smooth part on the mandrel, causing damage to the internal thread of the pipe fitting product or the mandrel. Therefore, a retraction device connected to the smooth part is provided, and the retraction device can retract the smooth part toward the axial direction of the mandrel, leaving space for accommodating the internal thread of the pipe fitting product.

[0008] Preferably, the mandrel includes a mandrel body and a rotating rod, the moving die assembly includes a first moving plate and a second moving plate, the mandrel body is rotatably installed on the first moving plate, the rotating rod is fixedly connected to the mandrel body and penetrates through the second moving plate, the retracting device is rotatably installed on the second moving plate and moves along the axial direction of the rotating rod under the drive of the second moving plate. A plurality of the threaded surfaces are distributed on the outer wall surface of the mandrel body, an installation groove is arranged between two adjacent threaded surfaces, the smooth part is slidably installed in the installation groove, and two sides of the retracting device are respectively slidably connected with the inner wall surface of the installation groove and the smooth part.

[0009] Preferably, the retracting device includes a connecting disc and a trapezoidal block. The connecting disc is rotatably installed on the second moving plate. The trapezoidal block is fixed on the connecting disc and inserted into the installation groove. The trapezoidal block is a frustum structure with a cross-sectional area decreasing towards the direction of the mandrel body. The trapezoidal block is respectively slidably connected with the installation groove and the smooth part.

[0010] Preferably, a first sliding rail and a second sliding rail are respectively arranged on one surface of the trapezoidal block close to the axis of the mandrel and one surface far from the axis. The first sliding rail and the second sliding rail are inverted trapezoid structures. A first sliding groove and a second sliding groove are respectively arranged on one surface of the installation groove close to the axis and one surface of the smooth part close to the axis. The first sliding groove is slidably connected with the first sliding rail, and the second sliding groove is slidably connected with the second sliding rail.

[0011] Preferably, a driving device is further arranged on the second moving plate. The driving device is connected to the rotating rod to drive the mandrel to rotate.

[0012] Preferably, the driving device includes a driving part, a connecting rod and a rotating plate. The rotating plate is fixed on the rotating rod. A U-shaped groove is arranged on the rotating plate. The connecting rod is slidably connected with the second moving plate. The connecting rod is provided with a protruding block. The protruding block is slidably connected with the U-shaped groove. The driving part is installed on the second moving plate. The driving part is connected to one end of the connecting rod.

[0013] Preferably, it also includes a spacing device, which includes a spacing rod, an elastic member and a sliding plate, the midpoint of the spacing rod is hinged to the first movable plate, a hook is provided at one end of the spacing rod close to the fixed mold assembly, and a second protrusion that can hook with the hook is provided on the fixed mold assembly, the two ends of the elastic member are respectively connected to the spacing rod and the first movable plate, a decoupling structure is provided at one end of the spacing rod away from the hook, the sliding plate is fixed to the first movable plate, a third sliding groove is provided on the sliding plate, a third protrusion is provided on the second movable plate, and the third protrusion is slidably connected to the third sliding groove.

[0014] Preferably, the unhooking structure is a unhooking groove, and the end of the unhooking groove away from the hook head is an inclined surface connected to the outer surface of the spacer rod, and a fourth protrusion is provided on the second movable plate, and the fourth protrusion is slidably connected to the unhooking groove.

[0015] Preferably, a starting device for controlling the rotation of the core rod is further provided on the second movable plate, and a detection head of the starting device is slidably connected to the outer wall surface of the sliding plate.

[0016] Preferably, the fixed mold assembly includes a first fixed mold plate, a cavity insert, a second fixed mold plate and a spring; the first fixed mold plate is fixedly connected to the second fixed mold plate, the cavity insert is slidably connected to the first fixed mold plate, and the bottom of the cavity insert is fixedly connected to the bottom of the groove of the first fixed mold plate through the spring.

[0017] Compared with the prior art, the beneficial effects of the present technical solution are as follows: a plurality of mutually spaced threaded surfaces and smooth portions are arranged on the outer wall surface of the mandrel, and while ensuring uniform threaded connection of the pipe fitting product in the circumferential direction, the mandrel can be pulled out by rotating a certain angle to align the smooth surface of the pipe fitting product with the threaded surface of the mandrel, which greatly improves the demoulding efficiency of the product. A retraction device is provided so that the smooth portion can collapse toward the axis of the mandrel, thereby avoiding the smooth portion from conflicting with the threaded surface of the pipe fitting product during rotation. A driving device is provided to drive the mandrel to rotate, thereby improving the degree of automation of the equipment. A spacing device is provided so that the retraction device can utilize the movement of the Dongmu component itself to provide energy, while spacing the movement of the first moving plate from the movement of the Dadel moving plate, thereby ensuring that demoulding is performed only after the retraction device is completed. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is an exploded view of the quick demoulding injection molding device for internal threaded pipe fittings of the utility model;

[0019] Figure 2 It is a three-dimensional diagram of the movable mold assembly of the internal thread pipe quick demoulding injection molding device of the utility model;

[0020] Figure 3 It is the right view of the moving die assembly of the quick demolding injection molding device for the internal thread pipe fittings of the present utility model;

[0021] Figure 4 It is the exploded view of the core rod of the quick demolding injection molding device for the internal thread pipe fittings of the present utility model;

[0022] Figure 5 It is the half-sectional view of the fixed die assembly of the quick demolding injection molding device for the internal thread pipe fittings of the present utility model.

[0023] In the attached drawings: 1. Fixed die assembly; 2. Moving die assembly; 3. Connecting piece; 4. Core rod; 5. Driving device; 6. Spacing device; 7. Starting device; 11. First fixed template; 12. Cavity insert plate; 13. Second fixed template; 14. Spring; 21. First moving plate; 22. Second moving plate; 41. Threaded surface; 42. Smooth surface; 43. Core rod body; 44. Rotating rod; 45. Retracting device; 46. Installation groove; 51. Driving part; 52. Connecting rod; 53. Rotating plate; 54. Raised block; 61. Spacing rod; 62. Elastic part; 63. Sliding plate; 64. Second raised part; 65. Hook-off groove; 66. Fourth raised part; 221. Third raised part; 421. First sliding groove; 451. Connecting disk; 452. Trapezoidal block; 453. First slide rail; 454. Second slide rail; 461. Second sliding groove. Detailed implementation manners

[0024] The attached drawings are only for illustrative purposes and cannot be construed as a limitation to this patent; for better illustrating this embodiment, some components in the attached drawings will be omitted, enlarged or reduced, which do not represent the dimensions of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the attached drawings may be omitted. The positional relationships described in the attached drawings are only for illustrative purposes and cannot be construed as a limitation to this patent.

[0025] In the attached drawings of the embodiments of the present utility model, the same or similar reference numerals correspond to the same or similar components; in the description of the present utility model, it should be understood that if there are terms such as "upper", "lower", "left", "right", "long", "short", etc. indicating the orientation or positional relationship, they are based on the orientation or positional relationship shown in the attached drawings, and are only for facilitating the description of the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationships in the attached drawings are only for illustrative purposes and cannot be construed as a limitation to this patent. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0026] The technical solutions of the present utility model will be further specifically described below through specific embodiments in conjunction with the attached drawings:

[0027] Example 1

[0028] Such as Figure 1As shown, an internal thread quick demoulding injection molding device comprises a fixed mold assembly 1, a movable mold assembly 2 and a connecting piece 3, wherein the movable mold assembly 2 is slidably connected to the fixed mold assembly 1 through the connecting piece 3, and a cavity for injection molding is provided in both the fixed mold assembly 1 and the movable mold assembly 2, and a core rod 4 is rotatably installed in the cavity of the movable mold assembly 2, and a plurality of threaded surfaces 41 and a smooth portion 42 are alternately provided on the outer wall surface of the core rod 4, and a retraction device 45 is also included, and the retraction device 45 is connected to the smooth portion 42 to drive the smooth portion 42 to move toward the inside of the core rod 4. When producing internal thread pipe fittings, firstly, the movable mold assembly 2 and the fixed mold assembly 1 are molded together, and the movable mold assembly 2 and the fixed mold assembly 1 are both slidably connected to the connecting piece 3, and the movable mold assembly 2 and the fixed mold assembly 1 can only move along the length direction of the connecting piece 3, and the connecting piece 3 ensures that the relative position of the movable mold assembly 2 and the fixed mold assembly 1 is accurate after the mold is closed, and the shape of the pipe fitting after injection molding will not be deformed due to the deviation of the relative position of the movable mold assembly 2 and the fixed mold assembly 1. The movable mold assembly 2 and the fixed mold assembly 1 are provided with a cavity. After the mold is closed, the core rod 4 is inserted into the cavity, and the cavity forms a closed space. The cavity determines the external shape of the pipe fitting, and the core rod 4 determines the internal shape of the pipe fitting. A threaded surface 41 is provided on the core rod 4, so that a thread matching the threaded surface 41 will also be produced inside the pipe fitting after injection molding. An injection port is provided on the fixed mold assembly 1, and the injection port is connected to the cavity. The injection molding material is injected into the cavity through the injection port to fill the space between the cavity and the core rod 4. After the injection molding material is cooled and solidified, a pipe fitting product is formed, and then the fixed mold assembly 1 is separated from the movable mold assembly 2, and the cavity changes from closed to open, and the product can be directly taken out of the cavity. When taking out the pipe fitting product, since the pipe fitting is formed with a thread by injection molding, and the core rod 4 is also provided with a threaded surface 41, the two form a threaded connection. When taking out the pipe fitting product, it is necessary to first release the threaded connection between the two. There are multiple threaded surfaces 41 evenly distributed on the outer wall surface of the core rod 4, and smooth parts 42 are provided between each threaded surface 41. When injection molding is performed, threads will only be formed on the threaded surface 41 of the core rod 4 inside the pipe fitting product, and a smooth inner wall surface will be formed on the smooth part 42. Since there are multiple threaded surfaces 41 evenly distributed on the outer wall surface of the core rod 4, the threads formed in the pipe fitting are also evenly distributed on the inner wall surface of the pipe fitting. During use, the pipe fitting product can also form a uniform threaded connection with other components along the circumferential direction without affecting the connection effect. When demolding the pipe fitting product and the core rod 4, it is only necessary to rotate the core rod 4 and rotate the threaded surface 41 of the core rod 4 to the smooth inner wall surface of the pipe fitting product, thereby releasing the threaded connection between the core rod 4 and the pipe fitting product, so that the core rod 4 can be directly pulled out of the pipe fitting product, which greatly improves the demolding efficiency of the core rod 4. Since the inner wall surface of the pipe product only fits the outer wall surface of the core rod 4 during injection molding, when the core rod 4 rotates, the internal thread on the pipe product will conflict with the smooth part 42 on the core rod 4, causing damage to the internal thread of the pipe product and the core rod 4.Therefore, a retraction device 45 is provided and connected to the smooth portion 42. The retraction device 45 can retract the smooth portion 42 in the axial direction of the mandrel 4 to leave a space for accommodating the internal thread of the pipe fitting product.

[0029] As Figure 4 shown, the mandrel 4 includes a mandrel body 43 and a rotating rod 44. The moving die assembly 2 includes a first moving plate 21 and a second moving plate 22. The mandrel body 43 is rotatably mounted on the first moving plate 21. The rotating rod 44 is fixedly connected to the mandrel body 43 and penetrates through the second moving plate 22. The retraction device 45 is rotatably mounted on the second moving plate 22 and moves along the axial direction of the rotating rod 44 under the drive of the second moving plate 22. A plurality of thread surfaces 41 are distributed on the outer wall surface of the mandrel body 43. An installation groove 46 is provided between two adjacent thread surfaces 41. The smooth portion 42 is slidably mounted in the installation groove 46. Both sides of the retraction device 45 are slidably connected to the inner wall surface of the installation groove 46 and the smooth portion 42 respectively. The retraction device 45 is mounted on the second moving plate 22 through a bearing, so that the retraction device 45 can only rotate on the second moving plate 22 and cannot have relative displacement. During demolding, first, the second moving plate 22 moves, and the second moving plate 22 drives the retraction device 45 to work, driving the smooth portion 42 to contract in the direction of the central axis of the mandrel 4. After the smooth portion 42 contracts, a vacant space will be formed between the smooth portion 42 and the inner wall surface of the pipe fitting product. Then, the rotating rod 44 is driven to rotate the mandrel 4. After rotation, the thread on the inner wall surface of the pipe fitting product rotates to the vacant space. At this time, there is no connection relationship between the thread on the inner wall surface of the pipe fitting product and the mandrel 4. Then, the first moving plate 21 and the second moving plate 22 are moved together to directly extract the mandrel 4 from the pipe fitting product, completing the demolding.

[0030] As Figure 4As shown in the figure, the retraction device 45 includes a connection disk 451 and a trapezoidal block 452. The connection disk 451 is rotatably mounted on the second moving plate 22. The trapezoidal block 452 is fixed to the connection disk 451 and inserted into the installation groove 46. The trapezoidal block 452 is a frustum structure with a cross-sectional area decreasing in the direction of the mandrel body 43. The trapezoidal block 452 is slidably connected to the installation groove 46 and the smooth portion 42. The connection disk 451 is rotatably connected to the second moving plate 22 and slidably connected to the rotating rod 44, so that the retraction device 45 can rotate together with the rotating rod 44. At the same time, the movement of the second moving plate 22 can provide power for the movement of the retraction device 45. The trapezoidal block 43 is fixed to the connection disk 451. The outer side and the inner side of the trapezoidal block 43 are respectively abutted against the inner side of the smooth portion 42 and the side of the installation groove 46 close to the axis. The distance between the outer side and the inner side of the trapezoidal block 43 continuously decreases in the direction of the mandrel body 43. When the second moving die 22 moves, it drives the connection disk 451 and then drives the trapezoidal block 452 to be withdrawn from the mandrel body 43. The distance between the outer side and the inner side of the trapezoidal block 452 that abuts against the installation groove 46 and the smooth portion 42 decreases, and the installation groove 46 cannot move, so that the smooth portion 42 has to approach the side of the installation groove 46 close to the axis, thereby realizing the retraction of the smooth portion 42 in the direction of the axis of the mandrel 2.

[0031] As Figure 4 shown in the figure, a first slide rail 453 and a second slide rail 454 are respectively arranged on the side of the trapezoidal block 452 close to the axis of the mandrel 4 and the side far from the axis. The first slide rail 453 and the second slide rail 454 are inverted trapezoid structures. A first chute 461 and a second chute 421 are respectively arranged on the side of the installation groove 46 close to the axis and the side of the smooth portion 42 close to the axis. The first chute 461 is slidably connected to the first slide rail 453, and the second chute 421 is slidably connected to the second slide rail 454. The inverted trapezoid structure slide rails not only play a role in sliding connection, but also prevent the two sliding-connected surfaces from moving away from each other. By providing the first chute 461, the second chute 421, the first slide rail 453 and the second slide rail 454, it is ensured that the outer side and the inner side of the trapezoidal block 43 are respectively always in contact with the inner side of the smooth portion 42 and the side of the installation groove 46 close to the axis.

[0032] As Figure 2 shown in the figure, a driving device 5 is also arranged on the second moving plate 22. The driving device 5 is connected to the rotating rod 44 to drive the mandrel 4 to rotate. After the retraction device 53 completes its work, the driving device 5 can drive the rotating rod 44 to rotate so that the threaded surface 41 on the mandrel body 43 is disengaged from the threaded surface on the inner wall surface of the pipe fitting product, eliminating the need for manual rotation of the rotating rod 44 and realizing the automation of the rotation process.

[0033] As Figure 3As shown in the figure, the driving device 5 includes a driving member 51, a connecting rod 52, and a rotating plate 53. The rotating plate 53 is fixed to the rotating rod 44. A U-shaped groove is provided on the rotating plate 53. The connecting rod 52 is slidably connected to the second moving plate 22. The connecting rod 52 is provided with a raised block 54, and the raised block 54 is slidably connected to the U-shaped groove. The driving member 51 is installed on the second moving plate 22, and the driving member 51 is connected to one end of the connecting rod 52. When the driving device 5 works, the driving member 51 drives the connecting rod 52 to slide on the second moving plate 22, and the connecting rod 52 is provided with a raised block 54 that is slidably connected to the U-shaped groove. Since the sliding direction of the connecting rod 52 is not collinear with the length direction of the U-shaped groove, when the connecting rod 52 moves, the raised block 54 will abut against the groove wall of the U-shaped groove and then drive the rotating plate 53 to rotate. The rotating plate 53 is also connected to the rotating rod 44, and finally drives the rotating rod 44 to rotate and then drives the mandrel 4 to rotate.

[0034] Embodiment 2

[0035] This embodiment is similar to the above Embodiment 1, except that, as Figure 1 shown, it further includes a spacing device 6. The spacing device 6 includes a spacing rod 61, an elastic member 62, and a sliding plate 63. The midpoint of the spacing rod 61 is hinged to the first moving plate 21. A hook is provided at one end of the spacing rod 61 close to the fixed mold assembly 1. A second raised portion 64 that can be hooked by the hook is provided on the fixed mold assembly 1. Two ends of the elastic member 62 are respectively connected to the spacing rod 61 and the first moving plate 21. A hook-removing structure is provided at one end of the spacing rod 61 away from the hook. The sliding plate 63 is fixed to the first moving plate 21. A third chute is provided on the sliding plate 63. A third raised portion 221 is provided on the second moving plate 22, and the third raised portion 221 is slidably connected to the third chute. When performing the demolding operation, the first moving plate 21 and the second moving plate 22 need to move at intervals to ensure that the smooth portion 42 retracts before demolding, so as to avoid contact and damage to the pipe fitting product. When the second moving plate 22 moves, since the spacing rod 61 is hinged to the first moving plate 21 and the hook on the spacing rod 61 hooks the second raised portion 64 on the fixed mold assembly 1, and the fixed mold assembly 1 cannot move, the first moving plate 21 and the fixed mold assembly 1 remain relatively stationary and cannot move, and at the same time, the third raised portion 221 slides in the third chute. When the second moving plate 22 moves to a certain position, the hook-removing mechanism is automatically activated, so that the hook on the spacing rod 61 is disengaged from the second raised portion 64. At the same time, the third raised portion 221 just slides to the end of the third chute. At this time, when the second moving plate 22 continues to move, the third raised portion 221 on the second moving plate 22 abuts against the groove wall of the third chute, and drives the first moving plate 21 to move together with the second moving plate 22 through the sliding plate 63, achieving the effect of moving at intervals.

[0036] As Figure 3As shown, the decoupling structure is a decoupling groove 65. One end of the decoupling groove 65 away from the hook head is an inclined surface connected to the outer surface of the spacer rod 61. A fourth protrusion 66 is provided on the second moving plate 22, and the fourth protrusion 66 is slidably connected to the decoupling groove 65. When the second moving plate 22 moves, it drives the fourth protrusion 66 to slide in the decoupling groove 65. When the fourth protrusion 66 slides to the end of the decoupling groove 65, the fourth protrusion 66 will slide from the decoupling groove 65 to the outer surface of the spacer rod 61 along the inclined surface. During this process, the fourth protrusion 66 drives the spacer rod 61 to rotate, so that the hook head is disengaged from the second protrusion 64, achieving the decoupling effect.

[0037] As Figure 3 shown, a starting device 7 for controlling the rotation of the mandrel 4 is also provided on the second moving plate 22. The detection head of the starting device 7 is slidably connected to the outer wall surface of the sliding plate 63. When the sliding plate 63 moves and is disengaged from the detection head of the starting device 7, the starting device 7 can control the rotation of the mandrel 4 by controlling the operation of the driving member 51, realizing the mutual cooperation between the spacing device 6 and the driving device 5.

[0038] Embodiment 3

[0039] This embodiment is similar to the above-mentioned Embodiment 1, except that the fixed mold assembly 1 includes a first fixed mold plate 11, a cavity insert plate 12, a second fixed mold plate 13 and a spring 14; the first fixed mold plate 11 is fixedly connected to the second fixed mold plate 13, the cavity insert plate 12 is slidably connected to the first fixed mold plate 11, and the bottom of the cavity insert plate 12 is fixedly connected to the bottom of the groove of the first fixed mold plate 11 through the spring 14. The first fixed mold plate 11 is used to install the fixed mold assembly 1, and the second fixed mold plate 13 is slidably connected to the cavity insert plate 12 to ensure that the position of the cavity insert plate 12 does not change. During the process of the mandrel 4 rotating and demolding, since the pipe fitting product cannot rotate, it will be axially forced to drive the cavity insert plate 12 to move inward and compress the spring 14, so that the pipe fitting product will not be demolded and deformed during the rotation of the mandrel 4.

[0040] Obviously, the above-mentioned embodiments of the present invention are only examples for clearly explaining the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made on the basis of the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent replacements and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. An injection molding device for rapid demolding of internal threads, characterized in that, It includes a fixed mold assembly (1), a movable mold assembly (2) and a connecting piece (3). The movable mold assembly (2) is slidably connected to the fixed mold assembly (1) through the connecting piece (3). Cavities for injection molding are provided in both the fixed mold assembly (1) and the movable mold assembly (2). A mandrel (4) is rotatably installed in the cavity of the movable mold assembly (2). A plurality of threaded surfaces (41) and smooth parts (42) are alternately arranged on the outer wall surface of the mandrel (4). It further includes a retraction device (45), and the retraction device (45) is connected to the smooth part (42) to drive the smooth part (42) to move towards the inside of the mandrel (4).

2. The internal-thread rapid demolding injection molding device according to claim 1, wherein, The mandrel (4) includes a mandrel body (43) and a rotating rod (44). The movable mold assembly (2) includes a first movable plate (21) and a second movable plate (22). The mandrel body (43) is rotatably installed on the first movable plate (21). The rotating rod (44) is fixedly connected to the mandrel body (43) and penetrates through the second movable plate (22). The retraction device (45) is rotatably installed on the second movable plate (22) and moves along the axial direction of the rotating rod (44) under the drive of the second movable plate (22). A plurality of the threaded surfaces (41) are distributed on the outer wall surface of the mandrel body (43). An installation groove (46) is arranged between two adjacent threaded surfaces (41). The smooth part (42) is slidably installed in the installation groove (46). Both sides of the retraction device (45) are slidably connected to the inner wall surface of the installation groove (46) and the smooth part (42).

3. The internal-thread rapid demoulding injection moulding device according to claim 2, wherein, The retraction device (45) includes a connecting disk (451) and a trapezoidal block (452). The connecting disk (451) is rotatably installed on the second movable plate (22). The trapezoidal block (452) is fixed on the connecting disk (451) and inserted into the installation groove (46). The trapezoidal block (452) is a frustum structure with a cross-sectional area decreasing towards the direction of the mandrel body (43). The trapezoidal block (452) is slidably connected to the installation groove (46) and the smooth part (42) respectively.

4. An internal thread rapid demolding injection molding device according to claim 3, characterized in that, A first slide rail (453) and a second slide rail (454) are respectively arranged on one side of the trapezoidal block (452) close to the axis of the mandrel (4) and one side far from the axis. The first slide rail (453) and the second slide rail (454) are inverted trapezoid structures. A first chute (461) and a second chute (421) are respectively arranged on one side of the installation groove (46) close to the axis and one side of the smooth part (42) close to the axis. The first chute (461) is slidably connected to the first slide rail (453), and the second chute (421) is slidably connected to the second slide rail (454).

5. The internal-thread rapid demoulding injection moulding device according to claim 2, characterized in that, A driving device (5) is further arranged on the second movable plate (22). The driving device (5) is connected to the rotating rod (44) to drive the mandrel (4) to rotate.

6. The injection molding device for rapid demolding of internal threads according to claim 5, wherein, The driving device (5) includes a driving member (51), a connecting rod (52), and a rotating plate (53). The rotating plate (53) is fixed to the rotating rod (44). A U-shaped groove is provided on the rotating plate (53). The connecting rod (52) is slidably connected to the second moving plate (22). The connecting rod (52) is provided with a raised block (54), and the raised block (54) is slidably connected to the U-shaped groove. The driving member (51) is installed on the second moving plate (22), and the driving member (51) is connected to one end of the connecting rod (52).

7. The injection molding device for rapid demolding of internal threads according to claim 2, wherein, It further includes a spacing device (6). The spacing device (6) includes a spacing rod (61), an elastic member (62), and a sliding plate (63). The midpoint of the spacing rod (61) is hinged to the first moving plate (21). A hook is provided at one end of the spacing rod (61) close to the fixed mold assembly (1). A second raised portion (64) capable of hooking with the hook is provided on the fixed mold assembly (1). Two ends of the elastic member (62) are respectively connected to the spacing rod (61) and the first moving plate (21). A hook detachment structure is provided at the end of the spacing rod (61) away from the hook. The sliding plate (63) is fixed to the first moving plate (21). A third chute is provided on the sliding plate (63). A third raised portion (221) is provided on the second moving plate (22), and the third raised portion (221) is slidably connected to the third chute.

8. A quick demolding injection molding device for internal threads according to claim 7, characterized in that, The hook detachment structure is a hook detachment groove (65). One end of the hook detachment groove (65) away from the hook is an inclined surface connected to the outer surface of the spacing rod (61). A fourth raised portion (66) is provided on the second moving plate (22), and the fourth raised portion (66) is slidably connected to the hook detachment groove (65).

9. The injection molding device for rapid demolding of internal threads according to claim 7, characterized in that, A starting device (7) for controlling the rotation of the mandrel (4) is further provided on the second moving plate (22). The detection head of the starting device (7) is slidably connected to the outer wall surface of the sliding plate (63).

10. The injection molding device for rapid demolding of internal threads according to claim 1, characterized in that, The fixed mold assembly (1) includes a first fixed mold plate (11), a cavity insert plate (12), a second fixed mold plate (13), and a spring (14). The first fixed mold plate (11) is fixedly connected to the second fixed mold plate (13). The cavity insert plate (12) is slidably connected to the first fixed mold plate (11), and the bottom of the cavity insert plate (12) is fixedly connected to the bottom of the groove of the first fixed mold plate (11) through the spring (14).

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