A compact inside core-pulling water cup cover upper shell injection mold based on secondary pushing

Abstract

The application discloses a compact inside core-pulling water cup cover upper shell injection mold based on secondary pushing, which comprises a mold closing surface of a fixed mold, wherein a cavity is arranged on the mold closing surface, and a pouring runner communicated with the cavity is arranged in the fixed mold; the movable mold comprises a movable mold frame, a core, a side core-pulling mechanism, a push plate, a bent pin fixing assembly, a bent pin and a pushing piece plate, the core is arranged opposite to the cavity and fixed with the movable mold frame, a sliding cavity and a sliding channel communicated with the sliding cavity are arranged in the core, the side core-pulling mechanism is slidably connected with the sliding cavity and the forming end of the side core-pulling mechanism is exposed, the push plate is slidably connected with the movable mold frame, the bent pin fixing assembly is located on the side of the push plate away from the fixed mold and slidably connected, the bent pin is fixed with the bent pin fixing assembly and transmissionally connected with the side core-pulling mechanism, and the pushing piece plate is slidably connected with the movable mold frame and transmissionally connected with the push plate. Through the cooperation of the secondary pushing structure, the inside reverse clamping core-pulling is first driven to complete the inside reverse clamping core-pulling when the mold is opened, and then the plastic part is pushed to demold, so that the problems of incomplete reverse clamping core-pulling, easy damage of the demolding part and loose layout of the mold in the prior art are solved.

Description

Technical Field

[0001] This invention relates to the field of injection mold technology, and more specifically to a compact inner core-pulling injection mold for a cup lid shell based on a two-stage ejection process. Background Technology

[0002] In the injection molding process of plastic parts such as water cup shells, an undercut structure perpendicular to the parting direction is often designed on the inner side of the plastic part to achieve the assembly and snap-fit ​​function. The existence of this structure brings core-pulling and demolding challenges to the mold. In the existing technology, for the molding of such plastic parts with internal undercuts, the undercut is usually removed by means of inclined ejector rods, internal sliders with inclined guide pillars for core pulling, or hydraulic core pulling. At the same time, the final demolding of the plastic part is completed by a secondary ejection mechanism. Common secondary ejection schemes include spring-driven, return pin + stop pin mechanical drive, and cylinder or hydraulic cylinder assisted type. In this case, the inclined ejector rod and internal slider core pulling mechanism remove the undercut through lateral movement, and then the ejector plate or ejector rod completes the first ejection. Subsequently, the spring force or the ejector rod of the injection molding machine achieves the second ejection, and finally the plastic part is removed from the mold core.

[0003] However, existing technologies still have many shortcomings in practical applications: First, the reliability of internal undercut demolding is poor. Due to the limitation of mold space on the movement stroke of the inclined ejector or inner slider, for undercut structures perpendicular to the parting direction, problems such as incomplete core pulling or uneven force on the plastic part during demolding often occur, leading to plastic part deformation, undercut breakage, and low yield. Second, it is difficult to achieve a compact mold design. In order to adapt to the movement of the core pulling mechanism and the secondary ejection mechanism, existing molds need to reserve more clearance space. Some secondary ejection mechanisms also need to add auxiliary components such as cam pull rods and hydraulic cylinders, resulting in a large overall mold volume, loose structure, and a large occupation of production space. Third, the coordination and reliability of the secondary ejection action are insufficient. Spring-driven secondary ejection mechanisms have problems such as easy spring failure and insufficient ejection force, while cylinder or hydraulic cylinder driven mechanisms increase the complexity and cost of the mold, and some mechanisms have the risk of motion interference, affecting the stability of production efficiency.

[0004] Therefore, how to provide a new type of compact inner core-pulling injection mold for cup lid shells based on secondary ejection, which can accurately complete the inner inverted core pulling while also achieving a compact mold layout, is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a compact inner core-pulling injection mold for a cup lid shell based on a secondary ejection, which aims to solve the above-mentioned technical problems of easy deformation and damage of plastic parts during demolding and loose mold layout.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A compact, internally-driven cup lid upper shell injection mold based on a secondary ejection process, wherein the inner surface of the cup lid upper shell has undercut features arranged perpendicular to its parting direction, including: The fixed mold has a cavity at its parting surface; The moving mold includes a moving mold base, a core, a side core puller, an ejector plate assembly, a bent pin fixing assembly, a bent pin, and an ejector plate. The core is arranged opposite to the cavity and is fixedly connected to the moving mold base. A sliding cavity is opened inside the core. A sliding channel corresponding to the undercut feature and communicating with the sliding cavity is opened on the outer surface of the core. The side core puller is slidably connected to the sliding cavity. The forming end of the side core puller is exposed on the outer surface of the core through the sliding channel. The ejector plate assembly is slidably connected to the moving mold base. The bent pin fixing assembly is located on the side of the ejector plate assembly facing away from the fixed mold and is slidably connected to the ejector plate assembly. The bent pin is fixedly connected to the bent pin fixing assembly and is drivenly connected to the side core puller. The ejector plate is located at the mold closing surface of the moving mold base and is slidably connected to the moving mold base and is drivenly connected to the ejector plate assembly. When the mold opens, the ejector rod of the injection machine pushes the bent pin fixing assembly and the bent pin to move first, so as to drive the side core puller to complete the side pulling. Then, it continues to push the ejector plate assembly and the ejector plate to move, so as to demold the plastic part.

[0008] Therefore, this invention achieves the molding of the upper shell of the cup lid by arranging the cavity of the fixed mold and the core of the moving mold relative to each other. The gating channel in the fixed mold ensures stable injection of the melt. At the same time, the moving mold frame provides the mounting support base. Through the fixed connection between the bent pin fixing component and the bent pin, the sliding cooperation between the side core pull and the core sliding cavity and sliding channel, and the transmission connection between the push plate and the ejector plate, a two-stage ejection structure design is adopted. When the mold is opened, the injection molding machine ejector rod first pushes the bent pin fixing component and the bent pin to move first, accurately driving the side core pull to disengage from the undercut feature that is perpendicular to the parting direction on the inner surface of the upper shell of the cup lid. Then, the push plate and ejector plate continue to push to complete the demolding of the plastic part. This effectively solves the technical problems of difficult core pulling and easy damage to the plastic part caused by the perpendicularity of the inner undercut feature to the parting direction. Moreover, all components are compactly integrated in the cooperation structure of the fixed mold and the moving mold. While ensuring the stability of molding and demolding, the compact design of the mold is achieved, which improves the molding quality and production efficiency of the plastic part.

[0009] Preferably, the free end of the bent pin is bent toward the side core-pulling direction, and the side core-pulling has a through guide channel along the parting direction. The guide channel has a guide surface one and a guide surface two that contact and abut with the inner and outer folded surfaces of the bent pin respectively. When the bent pin moves toward the fixed mold, its outer folded surface pushes the guide surface two to cause the forming end of the side core-pulling to disengage from the undercut feature. When the bent pin moves away from the fixed mold, its inner folded surface pulls the guide surface one to cause the forming end of the side core-pulling to reset.

[0010] Preferably, the moving mold frame includes a moving mold base plate, a pad, a support plate and a core fixing plate arranged in sequence and fixedly connected in sequence by screws and pins.

[0011] Preferably, the bent pin fixing assembly includes a bent pin fixing plate and a second push plate. The bent pin fixing plate faces away from the fixed mold and has an installation position corresponding to the position of the bent pin. The bent pin is inserted into the installation position and positioned. The second push plate is fastened to the bent pin fixing plate facing away from the fixed mold to support the fixed end of the bent pin.

[0012] Preferably, it also includes a guide assembly, which includes a guide post, a guide sleeve one, and a guide sleeve two. The guide post is fixedly connected to the core fixing plate. The push plate has a guide sleeve mounting hole at the position corresponding to the guide post. The guide sleeve one is fixedly connected to the guide sleeve mounting hole and slidably connected to the guide post. The fixed mold has a guide sleeve mounting position at the position corresponding to the guide post. The guide sleeve two is fixedly connected to the guide sleeve mounting position and slidably connected to the guide post.

[0013] Preferably, the push plate assembly has a sliding groove on the plate surface facing away from the fixed mold, the bent pin fixing assembly is located in the sliding groove and is slidably connected to the sliding groove, and the moving mold also includes a baffle, the baffle is fixedly connected to the plate surface of the push plate assembly facing away from the fixed mold, and the plate surface of the baffle extends toward the opening side of the sliding groove to cover part of the sliding groove, which is used to limit the bending pin fixing assembly.

[0014] Preferably, the push plate assembly includes a push rod fixing plate and a push plate one arranged sequentially along the direction away from the fixed mold. The push rod fixing plate is fastened to the push plate one. The push plate one has a sliding groove on its surface facing away from the fixed mold. A baffle is fixedly connected to the push plate one's surface facing away from the fixed mold.

[0015] Preferably, the moving mold also includes a push rod, which is fixedly connected to the push rod fixing plate. The support plate and the core fixing plate are provided with push rod through holes corresponding to the push rod positions. The free end of the push rod passes through the push rod through hole and contacts and abuts against the plate surface of the push plate facing away from the fixed mold.

[0016] Preferably, the moving mold also includes a return spring. The push plate has a spring mounting hole at the position corresponding to the bent pin. The return spring is sleeved on the outer periphery of the bent pin and elastically supported between the opposite surfaces of the push rod fixing plate and the bent pin fixing plate. It is used to assist in pushing the bent pin fixing assembly and the bent pin to return after the ejection action is completed, so as to drive the side core puller to return to its original position.

[0017] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a compact inner core-pulling water cup lid upper shell injection mold based on secondary ejection, which has the following beneficial effects: precise coordination of core pulling and demolding actions, and high quality of plastic parts: The present invention adopts a secondary ejection design of "core pulling first and demolding later". The bending pin fixing component and the bending pin move first through the injection molding machine ejector rod. With the help of the transmission cooperation between the bending pin and the guide surface of the side core pulling, the precise and complete separation of the inner undercut feature is achieved, avoiding the plastic part deformation and undercut breakage problems caused by interference between core pulling and demolding in the prior art; the subsequent ejector plate drives the ejector plate to demold smoothly, further ensuring the integrity of the plastic part and significantly improving the product yield. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0019] Figure 1 The attached figure is a top view of a compact inner core-pulling water cup lid upper shell injection mold based on the present invention; Figure 2 for Figure 1 Sectional view at point AA; Figure 3 for Figure 2 Sectional view at point A in the middle; Figure 4 for Figure 2 Sectional view at point B in the middle; Figure 5 The attached figure is a half-sectional view of the side core pulling method provided by the present invention; Figure 6 for Figure 1 Sectional view at point BB (after rotating 90 degrees).

[0020] Wherein: 1-Fixed mold; 2-Moving mold; 4-Guide assembly; 11-Cavity; 12-Gating runner; 21-Moving mold frame; 22-Core; 23-Side core pull; 24-Push plate assembly; 25-Bent pin fixing assembly; 26-Bent pin; 27-Push plate; 28-Baffle; 29-Push rod; 30-Reset spring; 41-Guide pillar; 42-Guide sleeve one; 43-Guide sleeve two; 211-Moving mold base plate; 212-Support plate; 213-Core fixing plate; 214-Padded block; 215-Tie rod; 221-Sliding channel; 231-Guide channel; 232-Guide surface one; 233-Guide surface two; 240-Sliding groove; 241-Push rod fixing plate; 242-Push plate one; 251-Bent pin fixing plate; 252-Push plate two; 2421-Spring mounting hole. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] See appendix Figure 1 To be continued Figure 3The present invention discloses a compact inner core-pulling water cup cap injection mold based on secondary ejection. The inner surface of the water cup cap upper shell has an undercut feature arranged perpendicular to its parting direction, including: a fixed mold 1 and a moving mold 2. A cavity 11 is provided at the mold closing surface of the fixed mold 1; The moving mold 2 includes a moving mold frame 21, a core 22, a side core puller 23, a push plate assembly 24, a bent pin fixing assembly 25, a bent pin 26, and a push plate 27. The core 22 is arranged opposite to the cavity 11 and is fixedly connected to the moving mold frame 21. A sliding cavity is formed inside the core 22, and a sliding channel 221 corresponding to the undercut feature and communicating with the sliding cavity is formed on the outer surface of the core 22. The side core puller 23 is slidably connected to the sliding cavity, and the forming end of the side core puller 23 is exposed on the outer surface of the core 22 through the sliding channel 221. The push plate assembly 24 is slidably connected to the moving mold frame 21 along the parting direction. Next, the bent pin fixing component 25 is located on the side of the ejector plate assembly 24 facing away from the fixed mold 1 and is slidably connected to the ejector plate assembly 24 along the mold parting direction. The bent pin 26 is fixedly connected to the bent pin fixing component 25 and is drivenly connected to the side core pull 23. The ejector plate 27 is located at the mold closing surface of the moving mold frame 21 and is slidably connected to the moving mold frame 21 and is drivenly connected to the ejector plate assembly 24. When the mold is opened, the ejector rod of the injection machine pushes the bent pin fixing component 25 and the bent pin 26 to move first, so as to drive the side core pull 23 to complete the side pull. Then, it continues to push the ejector plate assembly 24 and the ejector plate 27 to move, so as to demold the plastic part.

[0023] Specifically, the gating runner 12 includes a sub-runner and a gate. The sub-runner is formed by grooves respectively opened on the opposite surfaces of the fixed platen of the fixed mold 1 and the ejector plate 27, which are joined together after the mold is closed. The gate is opened on the fixed platen of the fixed mold 1 and is used to connect the sub-runner and the cavity 11.

[0024] More specifically, after the moving mold 2 and the fixed mold 1 are closed, the core 22 and the cavity 11 are arranged opposite to each other, and the two enclose a molding space that matches the shape of the upper shell of the cup lid.

[0025] See appendix Figure 3 and attached Figure 5The free end of the bent pin 26 is bent toward the side core-pulling direction. The side core-pulling 23 has a through guide channel 231 along the parting direction. The guide channel 231 has a guide surface 1 232 and a guide surface 233 that respectively contact and abut with the inner and outer folded surfaces of the bent pin 26. When the bent pin 26 moves toward the fixed mold 1, its outer folded surface pushes the guide surface 233 to cause the forming end of the side core-pulling 23 to disengage from the undercut feature. The bent pin 26 moves away from the fixed mold 1, and its inner folded surface pulls the guide surface 232 to reset the forming end of the side core-pulling 23. Thus, by bending the free end of the bent pin 26 toward the core-pulling direction and setting a through guide channel 231 with guide surface 1 232 and guide surface 233 on the side core-pulling 23, the contact and cooperation between the inner and outer folded surfaces of the bent pin 26 and the guide surfaces is used to achieve precise conversion of the linear movement of the bent pin 26 into the radial core-pulling and resetting movement of the side core-pulling 23.

[0026] See appendix Figure 6 The moving mold frame 21 includes a moving mold base plate 211, a pad 214, a support plate 212 and a core fixing plate 213 arranged in sequence and fixedly connected by screws and pins. The push plate assembly 24 is located between the moving mold base plate 211 and the support plate 212, and the core 22 is fixedly connected to the core fixing plate 213.

[0027] Specifically, the moving mold frame 21 also includes a tie rod 215. The screw end of the tie rod 215 passes through the moving mold base plate 211, the pad 214 and the support plate 212 in sequence, and is then fastened to the core fixing plate 213 to lock the moving mold base plate 211, the pad 214, the support plate 212 and the core fixing plate 213.

[0028] Specifically, the push plate assembly 24 and the moving mold frame 21 are slidably connected by guide pillars, guide sleeves or other linear sliding components.

[0029] See appendix Figure 4 The bent pin fixing assembly 25 includes a bent pin fixing plate 251 and a push plate 252. The bent pin fixing plate 251 faces away from the plate surface of the fixed mold 1 and has an installation position corresponding to the position of the bent pin 26. The bent pin 26 is inserted into the installation position and positioned. The push plate 252 is fastened to the plate surface of the bent pin fixing plate 251 facing away from the fixed mold 1 to support the fixed end of the bent pin 26.

[0030] See appendix Figure 6The system also includes a guide assembly 4, which comprises a guide post 41, a first guide sleeve 42, and a second guide sleeve 43. The guide post 41 is fixedly connected to the core fixing plate 213. The push plate 27 has a guide sleeve mounting hole corresponding to the position of the guide post 41. The first guide sleeve 42 is fixedly connected to the guide sleeve mounting hole and slidably connected to the guide post 41. The fixed mold 1 has a guide sleeve mounting position corresponding to the position of the guide post 41. The second guide sleeve 43 is fixedly connected to the guide sleeve mounting position and slidably connected to the guide post 41. Thus, by setting the guide assembly 4, which consists of the guide post 41, the first guide sleeve 42, and the second guide sleeve 43, wherein the guide post 41 is fixed to the core fixing plate 213, and the first guide sleeve 42 and the second guide sleeve 43 are respectively set on the push plate 27 and the fixed mold 1, precise guidance is provided for the push-out and reset movements of the push plate 27 and for the opening and closing of the fixed mold 1 and the moving mold 2.

[0031] See appendix Figure 4 The push plate assembly 24 has a sliding groove 240 on the plate surface facing away from the fixed mold 1. The bent pin fixing assembly 25 is located in the sliding groove 240 and is slidably connected to the sliding groove 240. The moving mold 2 also includes a baffle 28, which is fixedly connected to the plate surface of the push plate assembly 24 facing away from the fixed mold 1. The plate surface of the baffle 28 extends toward the opening side of the sliding groove 240 to cover part of the sliding groove 240, and is used to limit the bending pin fixing assembly 25.

[0032] In this embodiment, the push plate assembly 24 includes a push rod fixing plate 241 and a push plate 242 arranged sequentially in the direction away from the fixed mold 1. The push rod fixing plate 241 is fastened to the push plate 242. The push plate 242 has a sliding groove 240 on the plate surface facing away from the fixed mold 1. The baffle 28 is fixedly connected to the plate surface of the push plate 242 facing away from the fixed mold 1.

[0033] See appendix Figure 2 The moving mold 2 also includes a push rod 29, which is fixedly connected to the push rod fixing plate 241. The support plate 212 and the core fixing plate 213 are each provided with push rod through holes corresponding to the push rod 29. The free end of the push rod 29 passes through the push rod through hole and contacts the surface of the ejector plate 27 facing away from the fixed mold 1. Thus, this structure directly and effectively transmits the linear motion of the push plate assembly 24 to the ejector plate 27, driving it to complete the final demolding of the plastic part. The transmission chain is short and efficient, and the force transmission is stable.

[0034] See appendix Figure 4 The moving mold 2 also includes a return spring 30. A spring mounting hole 2421 is provided on the push plate 242 corresponding to the position of the bent pin 26. The return spring 30 is sleeved on the outer periphery of the bent pin 26 and elastically supported between the opposing surfaces of the push rod fixing plate 241 and the bent pin fixing plate 251. Therefore, after the ejection action is completed, the elastic force of the return spring 30 can assist in pushing the bent pin fixing assembly 25 and the bent pin 26 to quickly return to their original positions, thereby driving the side core puller 23 to return to its original position, preparing for the next mold closing and forming.

[0035] The specific principle of the compact inner core-pulling water cup cap injection mold based on secondary ejection provided in this embodiment is as follows: The working cycle of the mold begins in the mold-closed state. At this time, the fixed mold 1 and the moving mold 2 are locked under the action of the injection molding machine, and the cavity 11 and the core 22 together form the molding space of the water cup cap shell; the side core 23, under the pull of its return spring 30 and the inner folded surface of the bent pin 26, extends its molding end through the sliding channel 221 to the outer surface of the core 22, and cooperates with the cavity 11 to jointly form the undercut feature on the inner side of the plastic part; the bent pin fixing assembly 25 keeps in contact with the baffle 28 under the action of the return spring 30; the push plate assembly 24 and the push plate 27 are both in the initial position after reset. Molten plastic is injected through the gating channel 12 and fills the cavity, and solidifies to form the plastic part after pressure holding and cooling.

[0036] Phase 1: Inner Core Pulling. After the injection molding machine opens the mold, the main parting surface of the moving mold 2 and the fixed mold 1 separates, and the plastic part is wrapped around the core 22. Subsequently, the ejector pin of the injection molding machine extends and acts directly on the bent pin fixing assembly 25. Since the bent pin fixing assembly 25 and the push plate assembly 24 are slidably connected through the sliding groove 240, and there is a gap between them in the initial state, the thrust of the ejector pin first drives the bent pin fixing assembly 25 to slide relative to the push plate assembly 244 towards the fixed mold 1 within the sliding groove 240. The bent pin fixing assembly 25 drives the bent pin 26, which is fixedly connected to it, to move forward (towards the fixed mold 1) synchronously. The outer folded surface of the bent pin 26 contacts the guide surface 233 of the side core pull 23 and applies force. Since the side core pull 23 is constrained within the sliding cavity of the core 22, it can only move radially perpendicular to the parting direction. The linear forward movement of the bent pin 26 is converted into a radial thrust on the guide surface 233 through its inclined fold, thereby driving the side core pull 23 to retract into the core 22 along the sliding channel 221, so that its molding end completely disengages from the undercut area inside the plastic part. During this stage, the push plate assembly 24 and the push plate 27 remain stationary.

[0037] The second stage: ejection of the plastic part. When the bent pin fixing assembly 25 slides relative to the push plate assembly 24 and contacts the bottom surface of the sliding groove 240, the inner core pulling action is completely completed. At this time, the injection molding machine ejector continues to advance, and its thrust can no longer make the bent pin fixing assembly 25 move alone. Instead, it pushes the entire push plate assembly 24 (including the push rod fixing plate 241 and the push plate 242) together towards the fixed mold 1 through the bent pin fixing assembly 25. The movement of the push plate assembly 24 is transmitted through the push rod 29 fixed on it. The push rod 29 passes through the through holes of the support plate 212 and the core fixing plate 213 and directly abuts against the back of the push plate 27. Its working surface contacts the edge or surface of the plastic part, thereby smoothly and completely pushing the plastic part, which has been released from the undercut constraint, away from the core 22, achieving the final demolding.

[0038] Reset Process: After demolding, the injection molding machine ejector pin retracts. First, under the elastic force of the reset spring 30, the bent pin fixing assembly 25 is pushed back to its initial position (against the baffle 28), simultaneously causing the bent pin 26 to retract. When the bent pin 26 retracts, its inner folded surface acts on the guide surface 232 of the side core pull 23, pulling the side core pull 23 to slide radially outward along the sliding channel 221 until its forming end extends back to the working position, preparing for the next mold closing and forming. Subsequently, the mold closes, and the parting surface of the fixed mold 1 presses against the ejector plate 27 and / or the reset rod (not shown in the figure, but usually set), forcing the ejector plate 27, ejector rod 29, and the entire ejector plate assembly 24 to retract together, completely resetting to the initial state, waiting for the next injection cycle.

[0039] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0040] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A compact, inner-side pull-out cup lid upper shell injection mold based on a two-stage molding process, wherein the inner surface of the cup lid upper shell has undercut features arranged perpendicular to its parting direction, characterized in that, include: Fixed mold (1), wherein a cavity (11) is provided at the mold closing surface of the fixed mold (1); The moving mold (2) includes a moving mold frame (21), a core (22), a side core puller (23), a push plate assembly (24), a bent pin fixing assembly (25), a bent pin (26), and a push plate (27). The core (22) is arranged opposite to the cavity (11) and fixedly connected to the moving mold frame (21). A sliding cavity is provided inside the core (22). A sliding channel (221) is provided on the outer surface of the core (22) corresponding to the undercut feature and communicating with the sliding cavity. The side core puller (23) is slidably connected to the sliding cavity. The forming end of the side core puller (23) is exposed on the outer surface of the core (22) through the sliding channel (221). The push plate assembly (24) is connected to the moving mold frame (21). The curved pin fixing component (25) is located on the side of the push plate assembly (24) facing away from the fixed mold (1) and is slidably connected to the push plate assembly (24). The curved pin (26) is fixedly connected to the curved pin fixing component (25) and is drivenly connected to the side core pull (23). The push plate (27) is located at the mold closing surface of the moving mold frame (21) and is slidably connected to the moving mold frame (21) and is drivenly connected to the push plate assembly (24). When the mold is opened, the injection machine ejector pushes the curved pin fixing component (25) and the curved pin (26) to move first, so as to drive the side core pull (23) to complete the side pull. Then, it continues to push the push plate assembly (24) and the push plate (27) to move, so as to demold the plastic part.

2. The compact inner-side core-pulling water cup lid upper shell injection mold based on secondary ejection as described in claim 1, characterized in that, The free end of the bent pin (26) is bent toward the side core pulling direction. The side core pulling (23) is provided with a through guide channel (231) along the mold parting direction. The guide channel (231) is provided with a guide surface one (232) and a guide surface two (233) that respectively contact and abut with the inner and outer folded surfaces of the bent pin (26). The bent pin (26) moves toward the fixed mold (1). Its outer folded surface pushes the guide surface two (233) to drive the forming end of the side core pulling (23) to disengage from the undercut feature. The bent pin (26) moves away from the fixed mold (1). Its inner folded surface pulls the guide surface one (232) to drive the forming end of the side core pulling (23) to reset.

3. The compact inner-side core-pulling water cup lid upper shell injection mold based on secondary ejection as described in claim 1, characterized in that, The moving mold frame (21) includes a moving mold base plate (211), a pad (214), a support plate (212), and a core fixing plate (213) arranged in sequence and fixedly connected by screws and pins.

4. The compact inner-side core-pulling water cup lid upper shell injection mold based on secondary ejection as described in claim 3, characterized in that, The bent pin fixing assembly (25) includes a bent pin fixing plate (251) and a push plate two (252). The bent pin fixing plate (251) faces away from the plate surface of the fixed mold (1) and has an installation position corresponding to the position of the bent pin (26). The bent pin (26) is inserted into the installation position and positioned. The push plate two (252) is fastened to the plate surface of the bent pin fixing plate (251) facing away from the fixed mold (1) to support the fixed end of the bent pin (26).

5. The compact inner-side core-pulling water cup lid upper shell injection mold based on secondary ejection as described in claim 3, characterized in that, It also includes a guide assembly (4), which includes a guide post (41), a first guide sleeve (42) and a second guide sleeve (43). The guide post (41) is fixedly connected to the core fixing plate (213). The push plate (27) has a guide sleeve mounting hole corresponding to the position of the guide post (41). The first guide sleeve (42) is fixedly connected to the guide sleeve mounting hole and slidably connected to the guide post (41). The fixed mold (1) has a guide sleeve mounting position corresponding to the position of the guide post (41). The second guide sleeve (43) is fixedly connected to the guide sleeve mounting position and slidably connected to the guide post (41).

6. The compact inner-side core-pulling water cup lid upper shell injection mold based on secondary ejection as described in claim 4, characterized in that, The push plate assembly (24) has a sliding groove (240) on the plate surface facing away from the fixed mold (1). The bent pin fixing assembly (25) is located in the sliding groove (240) and is slidably connected to the sliding groove (240). The moving mold (2) also includes a baffle (28). The baffle (28) is fixedly connected to the plate surface of the push plate assembly (24) facing away from the fixed mold (1), and the plate surface of the baffle (28) extends toward the opening side of the sliding groove (240) to cover part of the sliding groove (240) for limiting the bending pin fixing assembly (25).

7. The compact inner-side core-pulling water cup lid upper shell injection mold based on secondary ejection as described in claim 6, characterized in that, The push plate assembly (24) includes a push rod fixing plate (241) and a push plate one (242) arranged sequentially in a direction away from the fixed mold (1). The push rod fixing plate (241) is fastened to the push plate one (242). The push plate one (242) has a sliding groove (240) on its surface facing away from the fixed mold (1). The baffle (28) is fixedly connected to the surface of the push plate one (242) facing away from the fixed mold (1).

8. The compact inner-side core-pulling water cup lid upper shell injection mold based on secondary ejection as described in claim 7, characterized in that, The moving mold (2) also includes a push rod (29), which is fixedly connected to the push rod fixing plate (241). The support plate (212) and the core fixing plate (213) are provided with push rod through holes corresponding to the push rod (29) at the positions of the push rod (29). The free end of the push rod (29) passes through the push rod through hole and contacts and abuts against the surface of the push plate (27) facing away from the fixed mold (1).

9. The compact inner-side core-pulling water cup lid upper shell injection mold based on secondary ejection as described in claim 7, characterized in that, The moving mold (2) also includes a return spring (30). The push plate (242) has a spring mounting hole (2421) corresponding to the position of the bent pin (26). The return spring (30) is sleeved on the outer periphery of the bent pin (26) and elastically supported between the opposite surfaces of the push rod fixing plate (241) and the bent pin fixing plate (251). It is used to assist in pushing the bent pin fixing assembly (25) and the bent pin (26) to reset after the ejection action is completed, so as to drive the side core puller (23) to reset.

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