Ejection mechanism for a three-plate mold and three-plate mold

Abstract

This application provides a demolding mechanism for a three-plate mold and a three-plate mold. The demolding mechanism for the three-plate mold includes a movable insert assembly and a drive assembly. The movable insert assembly includes a fixed insert and a movable insert. The fixed end of the fixed insert is connected to a pad plate, and the molding end of the fixed insert slides through the rear mold fixing plate and the rear mold molding core in sequence. The fixed insert has a stroke limiting hole and an inner sliding hole that are connected in sequence. The inner sliding hole extends from the fixed end face of the fixed insert to the molding end face of the fixed insert. The molding end of the movable insert slides in the inner sliding hole, and a sliding limiting part is formed at the end of the movable insert opposite to the molding end. This utility model uses multiple demolding actions to demold the cylindrical plastic part in stages. It cleverly uses multiple demolding actions to replace the single demolding action of the traditional technology, so as to better reduce the clamping force of the cylindrical plastic part, thereby making the cylindrical plastic part easier to demold and avoiding the problem of tearing defects in the cylindrical plastic part.

Description

Technical Field

[0001] This utility model relates to the technical field of demolding mechanism for injection molds used in three-plate molds, and in particular to a demolding mechanism for three-plate molds and a three-plate mold. Background Technology

[0002] When injection molding products, if the product cannot detach from the mold cavity normally, the edges or inner walls of the product will be pulled by the resistance inside the mold cavity, resulting in tear defects in the product.

[0003] Typically, during the demolding process, the plastic parts most prone to the aforementioned pulling phenomenon are cylindrical structures. This is because the cavities of such cylindrical plastic parts need to adhere to the rear mold, which causes the plastic to exert a large clamping force on the rear mold core or inserts. Therefore, the plastic part is subject to this clamping force during demolding, making it prone to pulling, especially for plastic parts with complex cavity structures and large longitudinal lengths; for example... Figure 1 and Figure 2 As shown, a cylindrical plastic part 11 (which is the outer shell of a projection device) has a cavity 101 formed on its back, and an inner hole 102 penetrating the front of the plastic part is formed in the middle of the cavity 101. This means that the cavity 101 and the inner hole 102 can simultaneously exert a large clamping force on the mold core or insert. However, the existing technology usually uses the ejection mechanism of the rear mold to eject the plastic part directly after the mold is opened. This ejection method is often difficult to demold. Even if the ejection force of the ejection mechanism is adjusted, and even if the ejection force is much greater than the clamping force of the cavity 101 and the inner hole 102 to force demolding, it is easy to cause tearing defects in the plastic part. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a demolding mechanism and a three-plate mold for three-plate molds that can demold cylindrical plastic parts in sections, thereby reducing the clamping force of the cylindrical plastic parts and making them easier to demold, thus avoiding the tearing defects of the cylindrical plastic parts.

[0005] The objective of this utility model is achieved through the following technical solution:

[0006] A demolding mechanism for a three-plate mold includes a rear mold fixing plate, a backing plate, two supporting square irons, a base plate, and an ejection assembly. The rear mold fixing plate has a rear mold forming core embedded in it. The two supporting square irons are spaced apart between the backing plate and the base plate. The ejection assembly is located between the two supporting square irons and is used to eject a cylindrical plastic part. The rear mold fixing plate is movably mounted on the backing plate. The demolding mechanism for the three-plate mold further includes:

[0007] A movable insert assembly includes a rear mold fixed insert and a rear mold movable insert. The fixed end of the rear mold fixed insert is connected to the pad plate. The molding end of the rear mold fixed insert slides through the rear mold fixed plate and the rear mold molding core in sequence. The rear mold fixed insert has a stroke limiting hole and an inner sliding hole that are connected in sequence. The stroke limiting hole is located on the end face of the fixed end of the rear mold fixed insert. The inner sliding hole extends from the end face of the fixed end of the rear mold fixed insert to the end face of the molding end of the rear mold fixed insert. The molding end of the rear mold movable insert slides in the inner sliding hole. A sliding limiting part is formed at the end of the rear mold movable insert opposite to the molding end of the rear mold movable insert. The sliding limiting part slides in the stroke limiting hole. The molding end of the rear mold fixed insert is used to be located in the cavity of the cylindrical plastic part during injection molding. The rear mold molding core is used to adhere to the outer peripheral wall of the cylindrical plastic part during injection molding.

[0008] The driving assembly includes at least two telescopic driving members; each telescopic driving member is embedded in a corresponding supporting square iron, and the power output end of each telescopic driving member passes through the pad plate and is connected to the rear mold fixing plate; after the mold is opened, the power output ends of the two telescopic driving members drive the rear mold fixing plate to move away from the pad plate, so as to drive the cavity of the cylindrical plastic part to be demolded from the molding end of the rear mold fixing insert, while the inner hole of the cylindrical plastic part drags the molding end of the rear mold movable insert to slide relative to the inner sliding hole; when the molding end of the rear mold movable insert slides relative to the inner sliding hole to a preset distance, the ejection assembly ejects the cylindrical plastic part.

[0009] In one embodiment, the height of the sliding limit portion is less than the depth of the travel limit hole.

[0010] In one embodiment, the pad is provided with a foolproof mounting groove;

[0011] The fixed end of the rear mold fixing insert is provided with a foolproof positioning part, which is located in the foolproof mounting groove and is detachably connected to the pad.

[0012] In one embodiment, the foolproof positioning part is connected or snapped with the pad screw.

[0013] In one embodiment, each of the telescopic actuators is a hydraulic cylinder actuator.

[0014] In one embodiment, the demolding mechanism for the three-plate mold further includes at least two auxiliary guide slides; the two auxiliary guide slides are respectively fixedly installed on two symmetrical sides of the rear mold fixing plate;

[0015] The pad has alignment grooves on its two symmetrical sides. The two auxiliary guide slides are arranged in a one-to-one correspondence with the two alignment grooves, so that the end of each auxiliary guide slide slides into the corresponding alignment groove.

[0016] In one embodiment, the ejection assembly includes a plurality of ejector pins and an ejector pin fixing plate and an ejector pin push plate sequentially disposed between two of the supporting square irons; the ejector pin fixing plate is used to fix one end of the plurality of ejector pins, and the other ends of the plurality of ejector pins are sequentially slid through the pad and the rear mold fixing insert to the forming end of the rear mold fixing insert; the ejector pin push plate is used to push the ejector pin fixing plate to move.

[0017] In one embodiment, the demolding mechanism for the three-plate mold further includes a plurality of travel limiting members; one end of each of the plurality of travel limiting members passes through the pad and is connected to the bottom surface of the rear mold fixing plate, and the other end of the travel limiting member forms a limiting platform.

[0018] In one embodiment, both the rear mold fixing insert and the rear mold movable insert are integrally formed structures.

[0019] A three-plate mold includes the demolding mechanism for a three-plate mold as described in any of the above embodiments.

[0020] Compared with the prior art, the present invention has at least the following advantages:

[0021] After the mold is opened, the rear mold fixing plate is driven to move away from the pad plate by two telescopic drive components. This allows the outer peripheral wall of the cylindrical plastic part to adhere to the molding core of the rear mold, thereby driving the cavity of the cylindrical plastic part to be demolded from the molding end of the rear mold fixing insert. Since the inner hole of the cylindrical plastic part covers the molding end of the rear mold movable insert, the inner hole of the cylindrical plastic part can drag the molding end of the rear mold movable insert to slide relative to the inner sliding hole. The sliding limit part is restricted by the stroke limit hole, so that the molding end of the rear mold movable insert slides relative to the inner sliding hole to a preset distance. Then, the cylindrical plastic part is ejected by the ejection component. Specifically, during the demolding process, the cavity of the cylindrical plastic part is first demolded from the molding end of the fixed insert of the rear mold, giving the cavity a tendency and space to deform towards the center of the inner hole after demolding. Then, the ejector assembly is used to eject the cylindrical plastic part, ultimately allowing the inner hole of the cylindrical plastic part to be demolded from the molding end of the movable insert of the rear mold. This effectively disperses the demolding strength of the cylindrical plastic part, thereby reducing the large clamping force exerted by the cavity and inner hole of the cylindrical plastic part on the fixed insert and movable insert of the rear mold. The demolding mechanism for a three-plate mold of this invention utilizes multiple demolding actions to demold the cylindrical plastic part in stages. That is, it cleverly uses multiple demolding actions to replace the single demolding action of the traditional technology, thereby effectively reducing the clamping force of the cylindrical plastic part and making it easier to demold, thus avoiding the problem of tearing defects in the cylindrical plastic part. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a structural diagram of a cylindrical plastic part;

[0024] Figure 2 This is a structural diagram of a cylindrical plastic part;

[0025] Figure 3 This is a schematic diagram of the demolding mechanism for a three-plate mold in one embodiment;

[0026] Figure 4 for Figure 3 The exploded view of a portion of the demolding mechanism used in a three-plate mold is shown.

[0027] Figure 5 for Figure 3 The diagram shows the structure of the demolding mechanism used in a three-plate mold.

[0028] Figure 6 This is a schematic diagram showing the state of the inner hole of the cylindrical plastic part before the molding end of the movable insert of the rear mold moves, without dragging it.

[0029] Figure 7 This is a schematic diagram showing the state of the cylindrical plastic part after the inner hole is dragged and the molding end of the movable insert of the mold moves.

[0030] Figure 8 Figure 3 The diagram shows a partial structural schematic of the demolding mechanism used in a three-plate mold.

[0031] Reference numerals: 10 for demolding mechanism of three-plate mold; 11 for cylindrical plastic part; 101 for cavity; 102 for inner hole; 13 for pad; 131 for anti-foolproof mounting groove; 132 for alignment slide groove; 14 for support square iron; 15 for base plate; 16 for ejection assembly; 161 for ejector pin; 162 for ejector pin fixing plate; 163 for ejector pin push plate; 100 for movable insert assembly; 110 for rear mold fixing insert; 1101 for stroke limiting hole; 1102 for inner sliding hole; 1110 for anti-foolproof positioning part; 120 for rear mold movable insert; 1210 for sliding limiting part; 200 for drive assembly; 210 for telescopic drive component; 300 for guide slide bar; 400 for stroke limiting component. Detailed Implementation

[0032] To facilitate understanding of this utility model, a more complete description will be given below with reference to the accompanying drawings. The drawings illustrate preferred embodiments of this utility model. However, this utility model can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this utility model.

[0033] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0035] This disclosure provides a demolding mechanism for a three-plate mold, including a rear mold fixing plate, a backing plate, two supporting square blocks, a base plate, and an ejection assembly. The rear mold fixing plate has a rear mold forming core embedded therein. The two supporting square blocks are spaced apart between the backing plate and the base plate. The ejection assembly is located between the two supporting square blocks and is used to eject a cylindrical plastic part. The rear mold fixing plate is movably mounted on the backing plate. The demolding mechanism for the three-plate mold also includes a movable insert assembly and a drive assembly. The movable insert assembly includes a rear mold fixing insert and a rear mold movable insert; the fixing end of the rear mold fixing insert is connected to the pad plate, and the molding end of the rear mold fixing insert slides through the rear mold fixing plate and the rear mold molding core in sequence. The rear mold fixing insert has a stroke limiting hole and an inner sliding hole that are connected in sequence. The stroke limiting hole is located on the end face of the fixing end of the rear mold fixing insert, and the inner sliding hole extends from the end face of the fixing end of the rear mold fixing insert to the end face of the molding end of the rear mold fixing insert. The molding end of the rear mold movable insert slides in the inner sliding hole, and a sliding limiting part is formed at the end of the rear mold movable insert opposite to the molding end of the rear mold movable insert. The sliding limiting part slides in the stroke limiting hole. The molding end of the rear mold fixing insert is used to be located in the pad plate during injection molding. Within the cavity of the cylindrical plastic part, the rear mold forming core is used to adhere to the outer peripheral wall of the cylindrical plastic part during injection molding; the driving assembly includes at least two telescopic driving members; each telescopic driving member is embedded in a corresponding support square iron, and the power output end of each telescopic driving member passes through the pad plate and is connected to the rear mold fixing plate; after the mold is opened, the power output ends of the two telescopic driving members drive the rear mold fixing plate to move away from the pad plate, thereby causing the cavity of the cylindrical plastic part to be demolded from the forming end of the rear mold fixing insert, while the inner hole of the cylindrical plastic part drags the forming end of the rear mold movable insert to slide relative to the inner sliding hole; when the forming end of the rear mold movable insert slides relative to the inner sliding hole to a preset distance, the ejection assembly ejects the cylindrical plastic part.

[0036] Please see Figures 1 to 8 To better understand the demolding mechanism 10 for a three-plate mold in this application, the following further explanation of the demolding mechanism 10 for a three-plate mold is provided:

[0037] One embodiment of the demolding mechanism 10 for a three-plate mold includes a rear mold fixing plate 12, a pad plate 13, two supporting square irons 14, a bottom plate 15, and an ejection assembly 16. The rear mold fixing plate 12 is fitted with a rear mold forming core 121. The two supporting square irons 14 are spaced apart between the pad plate 13 and the bottom plate 15. The ejection assembly 16 is located between the two supporting square irons 14 and is used to eject the cylindrical plastic part 11. The rear mold fixing plate 12 is movably mounted on the pad plate 13. The demolding mechanism 10 for a three-plate mold also includes a movable insert assembly 100 and a drive assembly 200. The movable insert assembly 100 includes a rear mold fixing insert 110 and a rear mold movable insert 120. The fixing end of the rear mold fixing insert 110 is connected to the pad plate 13, and the forming end of the rear mold fixing insert 110 slides through the rear mold fixing plate 12 and the rear mold forming core 121 in sequence. The rear mold fixing insert 110 has a stroke limiting hole 1101 and an inner sliding hole 1102 that are connected in sequence. The stroke limiting hole 1101 is located on the end face of the fixing end of the rear mold fixing insert 110. The inner sliding hole 1102 extends from the fixed end face of the rear mold fixing insert 110 to the molding end face of the rear mold fixing insert 110. The molding end of the rear mold movable insert 120 is slidably disposed in the inner sliding hole 1102. A sliding limiting part 1210 is formed at the end of the rear mold movable insert 120 opposite to the molding end of the rear mold movable insert 120. The sliding limiting part 1210 is slidably disposed in the stroke limiting hole 1101. The molding end of the rear mold fixing insert 110 is used for injection molding. The rear mold forming core 121 is located within the cavity 101 of the cylindrical plastic part 11 and is used to adhere to the outer peripheral wall of the cylindrical plastic part 11 during injection molding; the drive assembly 200 includes at least two telescopic drive members 210; each telescopic drive member 210 is embedded in the corresponding support square iron 14, and the power output end of each telescopic drive member 210 passes through the pad plate 13 and is connected to the rear mold fixing plate 12; after the mold is opened, the two telescopic drive members 210... The power output end drives the rear mold fixing plate 12 to move away from the pad plate 13, so as to drive the cavity 101 of the cylindrical plastic part 11 to demold from the molding end of the rear mold fixing insert 110. At the same time, the inner hole 102 of the cylindrical plastic part 11 drags the molding end of the rear mold movable insert 120 to slide relative to the inner sliding hole 1102. When the molding end of the rear mold movable insert 120 slides relative to the inner sliding hole 1102 to a preset distance, the ejection assembly 16 ejects the cylindrical plastic part 11.

[0038] In this embodiment, after the mold is opened, the rear mold fixing plate 12 is driven to move away from the pad plate 13 by two telescopic drive members 210. This allows the outer peripheral wall of the cylindrical plastic part 11 to adhere to the molding core 121 of the rear mold, thereby driving the cavity 101 of the cylindrical plastic part 11 to be demolded from the molding end of the rear mold fixing insert 110. Since the inner hole 102 of the cylindrical plastic part 11 covers the molding end of the rear mold movable insert 120, the inner hole 102 of the cylindrical plastic part 11 can drag the molding end of the rear mold movable insert 120 to slide relative to the inner sliding hole 1102. The sliding limit part 1210 is restricted to slide by the stroke limit hole 1101, so that the molding end of the rear mold movable insert 120 slides to a preset distance relative to the inner sliding hole 1102, and then the cylindrical plastic part 11 is ejected by the ejection component 16. Specifically, during the demolding process, the cavity 101 of the cylindrical plastic part 11 is first demolded from the molding end of the rear mold fixed insert 110, so that the cavity 101 of the cylindrical plastic part 11 has a tendency to deform towards the center of the inner hole 102 and a deformation space after demolding. Then, the ejector assembly 16 is used to eject the cylindrical plastic part 11, and finally the inner hole 102 of the cylindrical plastic part 11 is demolded from the molding end of the rear mold movable insert 120. This can better disperse the demolding intensity of the cylindrical plastic part 11, thereby reducing the large clamping force formed by the cavity 101 and inner hole 102 of the cylindrical plastic part 11 on the rear mold fixed insert 110 and the rear mold movable insert 120. The demolding mechanism 10 of this utility model for a three-plate mold uses multiple demolding actions to demold the cylindrical plastic part 11 in stages. That is, it cleverly uses multiple demolding actions to replace the single demolding action of the traditional technology, so as to reduce the clamping force of the cylindrical plastic part 11, making the cylindrical plastic part 11 easier to demold, thus avoiding the problem of tearing defects in the cylindrical plastic part 11.

[0039] It should be noted that the mold opening principle of the three-plate mold is existing technology, that is, the action after the rear mold of the three-plate mold separates from the front mold (not shown in the figure) to the predetermined mold opening position is existing technology. However, the demolding mechanism for the three-plate mold in this application is mainly for product demolding when the product adheres to the rear mold.

[0040] like Figure 1 , Figure 3 , Figure 4 , Figure 6 and Figure 7As shown, in one embodiment, the height of the sliding limiting part 1210 is less than the depth of the stroke limiting hole 1101. This allows the stroke limiting hole 1101 to provide a preset sliding distance for the sliding limiting part 1210. The maximum value of this sliding distance is specifically the maximum distance that the inner hole 102 of the cylindrical plastic part 11 can drag the molding end of the rear mold movable insert 120 relative to the inner sliding hole 1102. That is, the sliding limiting part 1210 restricts the sliding distance of the rear mold movable insert 120. It can be understood that when the rear mold movable insert 120 slides to the maximum distance, if the inner hole 102 of the cylindrical plastic part 11 continues to move and demold, the inner hole 102 of the cylindrical plastic part 11 will demold from the molding end of the rear mold movable insert 120.

[0041] Among them, such as Figure 6 In the figure, a is the depth of the stroke limiting hole 1101, b is the height of the sliding limiting part 1210, and the value of a minus the value of b is the distance that the inner hole 102 of the cylindrical plastic part 11 can drag the molding end of the rear mold movable insert 120 relative to the inner sliding hole 1102.

[0042] like Figure 3 , Figure 5 and Figure 8 As shown, in one embodiment, the pad 13 has a foolproof mounting groove 131; the fixed end of the rear mold fixing insert 110 has a foolproof positioning part 1110 protruding, the foolproof positioning part 1110 is disposed in the foolproof mounting groove 131, and the foolproof positioning part 1110 is detachably connected to the pad 13.

[0043] It is understood that by placing the foolproof positioning part 1110 inside the foolproof mounting groove 131 and connecting the foolproof positioning part 1110 to the pad plate 13, after the mold opens, the power output ends of the two telescopic drive members 210 drive the rear mold fixing plate 12 to move away from the pad plate 13, thereby causing the cavity 101 of the cylindrical plastic part 11 to be demolded from the molding end of the rear mold fixing insert 110. This keeps the rear mold fixing insert 110 stationary, while the rear mold fixing plate 12 drives the cylindrical plastic part 11 on the rear mold molding core 121 to move away from the pad plate 13. This causes the cylindrical plastic part 11 to move relative to the molding end of the rear mold fixing insert 110, thereby causing the cavity 101 of the cylindrical plastic part 11 to be demolded from the molding end of the rear mold fixing insert 110. The foolproof positioning part 1110 and the foolproof mounting groove 131, by adding a foolproof structure, can effectively improve the positioning accuracy of the mold assembly personnel when installing the rear mold fixing insert 110.

[0044] like Figure 8As shown, in one embodiment, the foolproof positioning part 1110 is screwed or snapped onto the pad 13. This facilitates the mold assembly personnel in assembling the rear mold fixing insert 110 onto the pad 13, thereby fixing the rear mold fixing insert 110 to the pad 13 and improving the structural stability of the rear mold fixing insert 110 after assembly.

[0045] like Figure 3 , Figure 5 and Figure 8 As shown, in one embodiment, each of the telescopic drive members 210 is a hydraulic cylinder drive member. Thus, by driving the rear mold fixing plate 12 away from the pad plate 13 with at least two hydraulic cylinders, the smoothness of the movement of the rear mold fixing plate 12 is ensured. Specifically, in this embodiment, four hydraulic cylinders are arranged near the four corners of the mold, providing sufficient thrust to push the rear mold fixing plate 12, making the movement of the rear mold fixing plate 12 away from the pad plate 13 smoother. This ensures that the rear mold fixing plate 12 can effectively drive the rear mold forming core 121 and the cylindrical plastic part 11 attached to the rear mold forming core 121 to undergo initial demolding, that is, the cavity 101 of the cylindrical plastic part 11 undergoes a demolding action from the forming end of the rear mold fixing insert 110.

[0046] like Figure 3 , Figure 5 and Figure 8 As shown, in one embodiment, the demolding mechanism 10 for the three-plate mold further includes at least two auxiliary guide slides 300; the two auxiliary guide slides 300 are respectively fixedly installed on two symmetrical sides of the rear mold fixing plate 12; the two symmetrical sides of the pad plate 13 are provided with alignment grooves 132, and the two auxiliary guide slides 300 and the two alignment grooves 132 are arranged in a one-to-one correspondence, so that the end of each auxiliary guide slide 300 slides into the corresponding alignment groove 132.

[0047] like Figures 3 to 5 As shown, in one embodiment, the ejector assembly 16 includes a plurality of ejector pins 161 and an ejector pin fixing plate 162 and an ejector pin push plate 163 sequentially disposed between the two supporting square irons 14; the ejector pin fixing plate 162 is used to fix one end of the plurality of ejector pins 161, and the other end of the plurality of ejector pins 161 sequentially passes through the pad plate 13 and the rear mold fixing insert 110 to the forming end of the rear mold fixing insert 110; the ejector pin push plate 163 is used to push the ejector pin fixing plate 162 to move.

[0048] It is understandable that since the projection of the cylindrical plastic part 11 on the parting surface all falls on the molding end of the rear mold fixing insert 110, in this embodiment, by using the other ends of multiple ejector pins 161 to slide through the pad 13 and the rear mold fixing insert 110 in sequence, and making the other ends of multiple ejector pins 161 reach the molding end of the rear mold fixing insert 110, it is possible to set an exhaust gap in the sliding hole of each ejector pin 161 and the rear mold fixing insert 110, thereby not only ensuring the venting effect of the mold cavity, which is beneficial to the molding quality of the cavity 101 and inner hole 102 of the cylindrical plastic part 11, but also enabling the ejector pin push plate 163 to push the ejector pin fixing plate 162 to move, and through the ejector pin fixing plate 162 to drive multiple ejector pins to simultaneously eject the cylindrical plastic part 11 for secondary demolding.

[0049] like Figure 5 As shown, in one embodiment, the demolding mechanism 10 for the three-plate mold further includes a plurality of travel limiting members 400; one end of each of the plurality of travel limiting members 400 passes through the pad 13 and is connected to the bottom surface of the rear mold fixing plate 12, and the other end of the travel limiting member 400 forms a limiting platform.

[0050] It is understood that by having one end of the travel limiter 400 pass through the pad 13 and connect to the bottom surface of the rear mold fixing plate 12, the travel limiter 400 is moved synchronously when the rear mold fixing plate 12 moves away from the pad 13. That is, when the rear mold fixing plate 12 moves away from the pad 13 beyond the maximum travel value, the limiter will abut against the pad 13, thereby restricting the further movement of the rear mold fixing plate 12. This effectively limits the travel of the rear mold fixing plate 12, ensuring the structural rationality and coordination of the demolding action of the cylindrical plastic part 11.

[0051] like Figure 4 As shown, in one embodiment, both the rear mold fixing insert 110 and the rear mold movable insert 120 are integrally molded structures. Thus, while ensuring the injection molding quality of the cylindrical plastic part 11, the rear mold fixing insert 110 and the rear mold movable insert 120 have good structural connection strength.

[0052] This application also provides a three-plate mold, including the demolding mechanism 10 for a three-plate mold as described in any of the above embodiments.

[0053] In this embodiment, the three-plate mold adopts the above-mentioned demolding mechanism for the three-plate mold. After the mold is opened, the rear mold fixing plate is driven to move away from the pad plate by two telescopic drive members. This allows the outer peripheral wall of the cylindrical plastic part to be adhered to the molding core of the rear mold, thereby driving the cavity of the cylindrical plastic part to be demolded from the molding end of the rear mold fixing insert. Since the inner hole of the cylindrical plastic part covers the molding end of the rear mold movable insert, the inner hole of the cylindrical plastic part can drag the molding end of the rear mold movable insert to slide relative to the inner sliding hole. The sliding limit part is restricted by the stroke limit hole, so that the molding end of the rear mold movable insert slides relative to the inner sliding hole to a preset distance, and then the cylindrical plastic part is ejected by the ejection component. Specifically, during the demolding process, the cavity of the cylindrical plastic part is first demolded from the molding end of the fixed insert of the rear mold, giving the cavity a tendency and space to deform towards the center of the inner hole after demolding. Then, the ejector assembly is used to eject the cylindrical plastic part, ultimately allowing the inner hole of the cylindrical plastic part to be demolded from the molding end of the movable insert of the rear mold. This effectively disperses the demolding strength of the cylindrical plastic part, thereby reducing the large clamping force exerted by the cavity and inner hole of the cylindrical plastic part on the fixed insert and movable insert of the rear mold. The demolding mechanism for a three-plate mold of this invention utilizes multiple demolding actions to demold the cylindrical plastic part in stages. That is, it cleverly uses multiple demolding actions to replace the single demolding action of the traditional technology, thereby effectively reducing the clamping force of the cylindrical plastic part and making it easier to demold, thus avoiding the problem of tearing defects in the cylindrical plastic part.

[0054] Compared with the prior art, the present invention has at least the following advantages:

[0055] After the mold is opened, the rear mold fixing plate is driven to move away from the pad plate by two telescopic drive components. This allows the outer peripheral wall of the cylindrical plastic part to adhere to the molding core of the rear mold, thereby driving the cavity of the cylindrical plastic part to be demolded from the molding end of the rear mold fixing insert. Since the inner hole of the cylindrical plastic part covers the molding end of the rear mold movable insert, the inner hole of the cylindrical plastic part can drag the molding end of the rear mold movable insert to slide relative to the inner sliding hole. The sliding limit part is restricted by the stroke limit hole, so that the molding end of the rear mold movable insert slides relative to the inner sliding hole to a preset distance. Then, the cylindrical plastic part is ejected by the ejection component. Specifically, during the demolding process, the cavity of the cylindrical plastic part is first demolded from the molding end of the fixed insert of the rear mold, giving the cavity a tendency and space to deform towards the center of the inner hole after demolding. Then, the ejector assembly is used to eject the cylindrical plastic part, ultimately allowing the inner hole of the cylindrical plastic part to be demolded from the molding end of the movable insert of the rear mold. This effectively disperses the demolding strength of the cylindrical plastic part, thereby reducing the large clamping force exerted by the cavity and inner hole of the cylindrical plastic part on the fixed insert and movable insert of the rear mold. The demolding mechanism for a three-plate mold of this invention utilizes multiple demolding actions to demold the cylindrical plastic part in stages. That is, it cleverly uses multiple demolding actions to replace the single demolding action of the traditional technology, thereby effectively reducing the clamping force of the cylindrical plastic part and making it easier to demold, thus avoiding the problem of tearing defects in the cylindrical plastic part.

[0056] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A demolding mechanism for a three-plate mold, comprising a rear mold fixing plate, a backing plate, two supporting square irons, a bottom plate, and an ejection assembly; wherein the rear mold fixing plate is embedded with a rear mold forming core, the two supporting square irons are spaced apart between the backing plate and the bottom plate, the ejection assembly is located between the two supporting square irons, the ejection assembly is used to eject a cylindrical plastic part, and the rear mold fixing plate is movably disposed on the backing plate, characterized in that... The demolding mechanism for the three-plate mold further includes: A movable insert assembly includes a rear mold fixed insert and a rear mold movable insert. The fixed end of the rear mold fixed insert is connected to the pad plate. The molding end of the rear mold fixed insert slides through the rear mold fixed plate and the rear mold molding core in sequence. The rear mold fixed insert has a stroke limiting hole and an inner sliding hole that are connected in sequence. The stroke limiting hole is located on the end face of the fixed end of the rear mold fixed insert. The inner sliding hole extends from the end face of the fixed end of the rear mold fixed insert to the end face of the molding end of the rear mold fixed insert. The molding end of the rear mold movable insert slides in the inner sliding hole. A sliding limiting part is formed at the end of the rear mold movable insert opposite to the molding end of the rear mold movable insert. The sliding limiting part slides in the stroke limiting hole. The molding end of the rear mold fixed insert is used to be located in the cavity of the cylindrical plastic part during injection molding. The rear mold molding core is used to adhere to the outer peripheral wall of the cylindrical plastic part during injection molding. The driving assembly includes at least two telescopic driving members; each telescopic driving member is embedded in a corresponding supporting square iron, and the power output end of each telescopic driving member passes through the pad plate and is connected to the rear mold fixing plate; after the mold is opened, the power output ends of the two telescopic driving members drive the rear mold fixing plate to move away from the pad plate, so as to drive the cavity of the cylindrical plastic part to be demolded from the molding end of the rear mold fixing insert, while the inner hole of the cylindrical plastic part drags the molding end of the rear mold movable insert to slide relative to the inner sliding hole; when the molding end of the rear mold movable insert slides relative to the inner sliding hole to a preset distance, the ejection assembly ejects the cylindrical plastic part.

2. The stripper mechanism for a three-plate die of claim 1 wherein, The height of the sliding limiting part is less than the depth of the travel limiting hole.

3. The stripper mechanism for a three-plate die of claim 1 wherein, The pad is provided with a foolproof mounting groove; The fixed end of the rear mold fixing insert is provided with a foolproof positioning part, which is located in the foolproof mounting groove and is detachably connected to the pad.

4. The stripper mechanism for a three-plate die of claim 3, wherein, The foolproof positioning part is connected or snapped with the pad screw.

5. The stripper mechanism for a three-plate die of claim 3 wherein, Each of the aforementioned telescopic drive components is a hydraulic cylinder drive component.

6. The stripper mechanism for a three-plate die of claim 1 wherein, The demolding mechanism for the three-plate mold further includes at least two auxiliary guide slides; the two auxiliary guide slides are respectively fixedly installed on two symmetrical sides of the rear mold fixing plate; The pad has alignment grooves on its two symmetrical sides. The two auxiliary guide slides are arranged in a one-to-one correspondence with the two alignment grooves, so that the end of each auxiliary guide slide slides into the corresponding alignment groove.

7. The stripper mechanism for a three-plate die of claim 1 wherein, The ejection assembly includes multiple ejector pins and an ejector pin fixing plate and an ejector pin push plate arranged sequentially between the two supporting square irons; the ejector pin fixing plate is used to fix one end of the multiple ejector pins, and the other end of the multiple ejector pins slides sequentially through the pad and the rear mold fixing insert to the forming end of the rear mold fixing insert; the ejector pin push plate is used to push the ejector pin fixing plate to move.

8. The stripper mechanism for a three-plate die of claim 1 wherein, The demolding mechanism for the three-plate mold further includes multiple stroke limiting components; one end of each stroke limiting component passes through the pad and is connected to the bottom surface of the rear mold fixing plate, and the other end of each stroke limiting component forms a limiting platform.

9. The stripper mechanism for a three-plate die of claim 1 wherein, Both the fixed rear mold insert and the movable rear mold insert are integrally formed structures.

10. A three-plate mold characterized by, The demolding mechanism for a three-plate mold includes any one of claims 1-9.

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