Plastic cup mold capable of rapidly demolding

Abstract

The utility model relates to the technical field of plastic mold forming, and discloses a plastic cup mold capable of being quickly demolded, which comprises a mold plate, a convex mold for forming an inner cavity of a cup body, a push plate, a material pushing assembly arranged on the push plate, and an ejection piece, the piston hole is formed in the template, the piston component penetrates through the push plate and is matched with the piston hole, the exhaust structure is arranged in the male die, and when the piston component pressurizes the piston hole, gas is filled between the top face of the male die and the bottom of the cup body through the exhaust structure, and the jacking piece drives the piston component to stretch into the piston hole. The piston component is provided with a driven assembly and a reset assembly, the driven assembly drives the push plate to move close to the mold plate along with the piston component when the piston component stretches into the piston hole and reaches a preset stroke, and the reset assembly drives the piston component to reset. Concave of the cup body generated when vacuum is converted into negative pressure is relieved.

Description

Technical Field

[0001] This utility model relates to the field of plastic mold forming technology, and in particular to a plastic cup mold that can be quickly demolded. Background Technology

[0002] Chinese Patent CN213107940U discloses a convenient PP plastic cup injection mold. The mold includes an upper mold and a lower mold. The lower mold has a protruding punch for forming the inner cavity of the cup, and the inner cavity of the cup fits with the punch. The upper mold has a recessed cavity. A push rod assembly is installed on the lower mold. A guide hole is opened on the lower mold for the push rod assembly to pass through. The end of the push rod assembly facing the punch is flush with the surface of the lower mold. The end of the push rod assembly facing away from the upper mold extends out of the lower mold and is connected to a push plate. The push plate abuts against a push rod. A driving component can drive the push plate to reciprocate towards or away from the lower mold by means of the push rod. A return spring is provided outside the push rod assembly. The lower mold has an internal air passage that connects to the guide hole. The inner wall of the guide hole has a recessed air groove that connects to the surface of the lower mold with the punch. The end of the push rod assembly has a protrusion that can block the air groove, and the other end is opened on the outside of the lower mold and connected to an air supply device.

[0003] In the above scheme, after the upper mold separates from the lower mold, the inner wall of the cup after injection molding adheres to the punch and is carried out of the mold cavity. When the cup is completely detached from the mold cavity, the ejector pin contacts the push plate and drives the ejector plate closer to the lower mold, causing the ejector pin assembly to move a preset distance. At this time, the ejector pin assembly extends towards the end of the punch and first pushes the opening of the cup away a certain distance before stopping. The punch moves synchronously with the ejector pin assembly, opening the air groove and connecting the air groove with the gap between the cup and the punch. At this time, the air supply device inputs gas into the air channel. The gas flows from the air channel into the air groove and fills the inner cavity of the cup, filling the gap between it and the punch, thus breaking the vacuum adsorption state. Then the ejector pin continues to push forward, pushing the cup away from the punch. The above scheme utilizes the ejector pin to demold while simultaneously pushing the cup and the punch together. Gas is filled in the space between the cups to quickly remove them from the vacuum adsorption state, making them easier to remove. However, during the initial push of the cup by the pusher assembly, there is a transition from vacuum to adsorption. During the push, the inner wall of the cup can slide along the outer wall of the punch, resulting in a cavity between the cup and the top of the punch. The external air pressure will compress the cup, causing a certain indentation at the bottom. The indentation will disappear after the gas is filled in, but the cup will retain some stress when it is indented. Since plastics generally have the phenomenon of post-shrinkage, the material will shrink and deform after being left for a period of time after curing. When the cup material undergoes post-shrinkage, the residual stress generated during the ejection of the mold will aggravate the degree of deformation of the cup, leading to an increase in the defect rate. Therefore, there is still room for improvement in the existing demolding method of plastic cup molds. Utility Model Content

[0004] To address the shortcomings of existing plastic cup molds, which tend to cause the bottom of the cup to sink during demolding, resulting in residual deformation stress within the material and exacerbating the deformation when the plastic shrinks, the purpose of this invention is to provide a plastic cup mold that allows for rapid demolding and reduces the degree of cup deformation during demolding, thereby reducing residual stress in the cup material.

[0005] To solve the above-mentioned technical problems, the present invention provides a solution through the following technical method:

[0006] A quick-release plastic cup mold includes a template, a punch protruding from the template for forming the inner cavity of the cup, a push plate disposed on the side of the template opposite to the punch and capable of approaching or moving away from the template, a pusher assembly disposed on the push plate, and a top holder disposed movably relative to the push plate. The template is provided with a gas supply mechanism, which includes a piston hole disposed on the template, a piston component passing through the push plate and telescopically cooperating with the piston hole, and an exhaust structure disposed in the punch that fills the space between the top surface of the punch and the bottom of the cup body to counteract negative pressure when the piston component pressurizes the piston hole. The top holder can drive the piston component to extend into the piston hole. The piston component is provided with a driven assembly that drives the push plate to follow the piston component closer to the template when the piston component extends into the piston hole and reaches a preset stroke, and a reset assembly that drives the piston component to reset when the top holder moves away from the piston component.

[0007] In this scheme, when the piston component is driven by the top holding component to approach the template, it will move independently a preset distance before driving the push plate. Then, the piston component uses the driven component to drive the push plate to approach the template, and the pusher assembly continuously pushes the cup away from the punch. Compared with the prior art, during the independent movement of the piston component, the piston hole and the exhaust structure are pressurized and a small amount of air is filled into the space between the cup and the punch to form an air gap. During the synchronous movement of the piston component and the push plate, the pusher assembly pushes the cup away from the punch. At this time, a cavity will be generated between the cup and the punch. Since the piston component and the push plate advance synchronously, and an air gap has been formed between the cup and the punch before, and the exhaust structure is under positive pressure, when the cavity appears, the gas will immediately fill the cavity, realizing the pressure balance inside and outside the cup. This alleviates the situation where the cup is dented due to the influence of external air pressure when it is lifted, and alleviates the situation where the cup is deformed more severely during subsequent shrinkage due to residual stress inside the material. This can effectively reduce the defect rate.

[0008] Preferably, the driven component includes a first protruding ring disposed on the piston component, the first protruding ring being located on the side of the push plate facing away from the template and having a predetermined distance between it and the push plate.

[0009] Using the above scheme, when the piston component approaches the template, the first convex ring moves with the piston component and approaches the push plate, then abuts against the push plate and drives the push plate and piston component to approach the template together. The preset distance in this scheme is the distance the piston component moves independently of the push plate. The designer can set the preset distance according to the specific shape, wall thickness or material hardness of the cup body, and reasonably control the amount of gas filled into the cup body and punch when the piston component moves independently, so as to minimize the phenomenon of reverse expansion of the cup body due to excessive positive pressure.

[0010] Preferably, the first convex ring is movably disposed on the piston component, and an adjustment structure for adjusting the size of the preset distance is provided between the first convex ring and the piston component.

[0011] Preferably, the adjustment structure includes a threaded section on the piston component and a threaded hole on the first convex ring that is screwed into the threaded section.

[0012] The above solution takes into account that the mold can produce more product models by changing the punch. Therefore, the first punch ring in this solution is designed to be adjustable. Whenever the punch is changed, the operator can adjust the position of the first punch ring according to the cup body to be produced next time. During the production process, the operator can also adjust the first punch ring in real time according to the actual deformation of the product to reduce the subsequent defect rate.

[0013] Preferably, the reset assembly includes a second convex ring fixedly disposed on the piston component and located between the push plate and the template, and a first elastic member disposed between the second convex ring and the template.

[0014] Using the above scheme, one end of the first elastic member abuts against the template, and the other end abuts against the second convex ring. When the top holding member drives the piston component closer to the template, the first elastic member is in a state of gradual compression. When the top holding member moves away from the piston component, the first elastic member drives the piston component away to the initial state.

[0015] Preferably, the piston component includes a cylinder that is guided through the push plate and a piston rod that is guided and telescopically arranged relative to the cylinder. The end of the piston rod that protrudes from the cylinder forms a piston end. A driven component is arranged on the guide rod. A second elastic element is provided between the cylinder and the piston rod to drive the piston rod to remain in the extended state.

[0016] With the above solution, the depth of the piston hole is limited by the height of the punch, and space must be reserved in the punch for setting up the venting structure. This may result in the depth of the piston hole being less than the active stroke of the push plate. There is a possibility that the push plate will not move to its maximum stroke when the piston component is against the bottom of the piston hole. In this solution, the piston component is designed to be a component with elastic extension and retraction capabilities. When the above situation occurs, the piston rod will retract into the cylinder to avoid it. When the piston component moves away from the template, the second elastic element drives the piston rod to extend and reset.

[0017] Preferably, the exhaust structure includes exhaust grooves at both ends that are connected to the inner wall of the piston hole and the top surface of the punch, respectively, and an air pin is provided at the opening of the exhaust groove on the top surface of the punch.

[0018] Using the above solution, the air pin can be flush with the top of the punch after being inserted into the opening. During injection molding, it can cover the air groove opening to prevent material from entering the air groove. When the piston component pressurizes, the head of the air pin will extend when the pressure in the air groove reaches its limit, partially opening the air groove opening and venting the air. At the same time, its extension can also help to lift the cup body, making it easier to create an air gap between the cup body and the punch.

[0019] Preferably, n venting grooves are provided, with one venting groove opening at the center of the top surface of the punch, and n-1 venting groove openings evenly spaced around the edge of the end face of the punch.

[0020] By adopting the above solution, the design allows for even airflow from all parts of the bottom of the cup, and under positive pressure, the air pins can lift the cup from multiple points, resulting in more even force distribution, reducing the likelihood of protrusions and lowering the defect rate.

[0021] Preferably, the pusher assembly includes a pair of push rods protruding from the pusher plate, the ends of the push rods passing through the template and flush with the end of the template facing the punch, and a third elastic element is provided on the push rod sleeve to drive the pusher plate away from the template.

[0022] This utility model, by adopting the above technical solution, has significant technical effects: When the piston component in this solution is driven by the top holding component to approach the template, it will move independently a preset distance before driving the push plate. Then, the piston component uses the driven component to drive the push plate to approach the template, and the pusher assembly continuously pushes the cup body away from the punch. Compared with the prior art, during the independent movement of the piston component, the piston hole and the exhaust structure are pressurized and a small amount of air is filled into the space between the cup body and the punch to form an air gap. During the synchronous movement of the piston component and the push plate, the pusher assembly pushes the cup body away from the punch. At this time, a cavity will be generated between the cup body and the punch. Since the piston component and the push plate advance synchronously, and an air gap has been formed between the cup body and the punch before, and the exhaust structure is under positive pressure, when the cavity appears, the gas will immediately fill the cavity, realizing the pressure balance inside and outside the cup body. This alleviates the situation where the cup body is dented due to the influence of external air pressure when it is lifted, and alleviates the situation where the cup body is aggravated by the residual stress inside the material during subsequent shrinkage, which can effectively reduce the defect rate. Attached Figure Description

[0023] Figure 1 This is a three-dimensional structural diagram of a plastic cup mold that can be quickly demolded according to this embodiment;

[0024] Figure 2 This is a right view of a plastic cup mold that can be quickly demolded according to this embodiment;

[0025] Figure 3 yes Figure 2 A sectional view of AA in the middle;

[0026] Figure 4 yes Figure 3 A magnified view of the portion related to B in the image;

[0027] Figure 5 yes Figure 3 A magnified view of the portion related to C;

[0028] Figure 6 yes Figure 3 Diagram showing the state changes of the piston assembly when the central support member drives the piston component to move independently;

[0029] Figure 7 yes Figure 6 The diagram shows the state changes of the push plate driven by the first convex ring as it moves synchronously with the piston assembly.

[0030] The parts referred to by the numbers in the above attached figures are as follows: 1. Base plate; 101. Center hole; 2. Guide post; 3. Template; 4. Punch; 5. Cup body; 6. Push plate; 7. Top support; 8. Piston hole; 9. Piston assembly; 901. Cylinder; 902. Piston rod; 903. Piston end; 10. First convex ring; 11. Threaded section; 12. Threaded hole; 13. Second convex ring; 14. First elastic element; 15. Exhaust groove; 16. Air pin; 17. Push rod; 18. Third elastic element. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0032] Example

[0033] A quick-release plastic cup mold, based on Figure 1 , 3 As shown, the device includes a base plate 1, on which several guide posts 2 are protruding. A template 3 is fixedly mounted on each guide post 2. A punch 4 for forming the inner cavity of the cup body 5 is protruding on the template 3. A push plate 6, which can move closer to or away from the template 3, is fitted on the side of the template 3 facing away from the punch 4. A pusher assembly is provided on the push plate 6, which includes a pair of push rods 17 protruding from the push plate 6. The ends of the push rods 17 pass through the template 3 and are flush with the end of the template 3 facing the punch 4. A third elastic element 18 is fitted around the push rods 17 to drive the push plate 6 away from the template 3. The movement of the push plate 6 is controlled by a top holder 7. In this embodiment, the mold is produced in conjunction with the injection molding machine. The guide post 2 is connected to the drive body on the injection molding machine. By pulling the guide post 2, the template 3 and the base plate 1 move synchronously. The top holder 7 is fixedly set on the moving template 3 of the injection molding machine. When the base plate 1 approaches the top holder 7, the top holder 7 can restrict the push plate 6 from continuing to follow the base plate 1 and use the pulling force of the injection molding machine to drive the push plate 6 to move closer to the template 3. The above is the prior art and will not be described in detail in this embodiment.

[0034] The improvement in this embodiment is that the template 3 is provided with a gas delivery mechanism, according to... Figure 3 As shown, the gas delivery mechanism includes a piston hole 8 on the side of the template 3 facing away from the protrusion. A piston component 9, which telescopically engages with the piston hole 8, passes through the push plate 6. A central hole 101 is provided on the bottom plate 1 to allow the piston component 9 to move. When the bottom plate 1 approaches the top support 7, the piston component 9 is driven by the top support 7 to extend into the piston hole 8. When the bottom plate 1 returns to its original position and the piston component 9 moves away from the top support 7, the piston component 9 is driven by a reset assembly to return to its initial position. Figure 3 , 6As shown in Figure 7, the reset assembly includes a second protruding ring 13 fixedly mounted on the cylinder 901. The second protruding ring 13 is located between the push plate 6 and the template 3. A first elastic element 14 is provided between the second protruding ring 13 and the template 3. The punch 4 is provided with an exhaust structure that connects the piston hole 8 and the outer wall of the punch 4. The top holding member 7 abuts against the piston component 9 and drives the piston component 9 to pressurize into the piston hole 8. When the piston component 9 extends into the piston hole 8, it can pressurize into the piston hole 8 and the exhaust structure, driving the gas to enter the cup body 5 and the punch 4 through the air pin 16 to form an air gap.

[0035] The piston component 9 is equipped with a driven assembly, according to Figure 3 , 6 As shown in Figure 7, the driven component includes a first convex ring 10 movably disposed on the piston component 9. The first convex ring 10 is located on the side of the push plate 6 facing away from the template 3 and has a preset distance between it and the push plate 6. The first convex ring 10 is provided with an adjustment structure between it and the piston component 9 for adjusting the size of the preset distance. Figure 4 As shown, the adjustment structure includes a threaded section 11 on the piston component 9 and a threaded hole 12 on the first convex ring 10 that is screwed into the threaded section 11. When the top holding member 7 drives the piston component 9 to move, the preset distance between the first convex ring 10 and the push plate 6 will be reduced. When the first convex ring 10 abuts against the push plate 6, it can drive the push plate 6 and the piston component 9 to move synchronously closer to the template 3 to push the material.

[0036] according to Figure 3 , 6 As shown in Figure 7, the piston component 9 includes a cylinder 901 that is guided through the push plate 6. A piston rod 902 is guided and telescopically arranged inside the cylinder 901. A second elastic element is provided between the cylinder 901 and the piston rod 902 to drive the piston rod 902 to remain in an extended state. In this embodiment, the combination of the cylinder 901 and the piston rod 902 is a gas spring. The gas spring can drive the piston rod 902 to remain in an extended state. The end of the piston rod 902 that protrudes from the cylinder 901 is provided with a piston end 903 that mates with the piston hole 8.

[0037] according to Figure 3 , 5 As shown, the exhaust structure includes exhaust grooves 15 with both ends connected to the inner wall of the piston hole 8 and the top surface of the punch 4, respectively. An air pin 16 is provided at the opening of the exhaust groove 15 on the top surface of the punch 4. There are n exhaust grooves 15. One exhaust groove 15 opening is opened at the center of the top surface of the punch 4. n-1 exhaust groove 15 openings are evenly spaced around the edge of the end face of the punch 4. When the piston component 9 pressurizes the piston hole 8, the air pin 16 turns into a positive pressure state and slightly lifts the cup body 5. The gas flows into the exhaust groove 15 and fills the gap between the cup body 5 and the punch 4 through the opening of the air pin 16.

[0038] Based on the above structure, refer to Figures 1-7 It can be seen that the demolding process of a quick-release plastic cup mold in this solution is as follows:

[0039] After injection molding is completed, the main drive of the injection molding machine moves the base plate 1 and the template 3 closer to the top support 7. When the top support 7 abuts against the piston component 9, the piston component 9 begins to pressurize into the piston hole 8, so that positive pressure is formed in the exhaust groove 15 and a small amount of gas is filled into the gap between the cup body 5 and the punch 4 through the air pin 16. Then the first convex ring 10 abuts against the push plate 6 and drives the push plate 6 closer to the template 3. The push rod 17 pushes the cup body 5 away from the punch 4. During this process, a cavity will appear between the cup body 5 and the punch 4 and the cavity will become larger and larger. At the same time, the piston component 9 continues to pressurize into the piston hole 8, so that air is continuously filled into the cavity, reducing the air pressure difference inside and outside the cup body 5 until the cup body 5 separates from the punch 4.

[0040] When the injection molding machine drives the base plate 1 to reset, the push plate 6 and the piston component 9 are driven by the combined force of the first elastic element 14 and the third elastic element 18, moving away from the template 3 together. During the process of the piston component 9 exiting the piston hole 8, the air outside the punch 4 will be refilled into the piston hole 8 through the gap of the air pin 16, so that the air supply mechanism is ready for the next demolding.

[0041] In this embodiment, a plastic cup mold that can be quickly demolded has a piston component 9 that performs an independent movement before the push rod 17 pushes the cup body 5 away. This creates a positive pressure air gap between the cup body 5 and the punch 4, which alleviates the situation where the cup body 5 is dented due to external air pressure when it is lifted. This reduces the stress caused by the dent in the cup body 5 and alleviates the situation where the cup body 5 is subjected to increased deformation during subsequent shrinkage due to residual stress in the material. This can effectively reduce the defect rate.

[0042] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A plastic cup mold capable of quick demolding, comprising a mold plate (3), a male mold (4) protruding from the mold plate (3) and used for forming an inner cavity of a cup body (5), a push plate (6) capable of approaching or moving away from the mold plate (3) and arranged on a side of the mold plate (3) opposite to the male mold (4), a pushing assembly arranged on the push plate (6), and a top holder (7) movably arranged relative to the push plate (6), characterized in that: The template (3) is provided with a gas feeding mechanism, which comprises a piston hole (8) provided on the template (3), a piston component (9) penetrating through the push plate (6) and being in telescopic cooperation with the piston hole (8), and an exhaust structure provided in the punch (4) and filling gas between the top surface of the punch (4) and the bottom of the cup body (5) to offset the negative pressure when the piston component (9) pressurizes the piston hole (8). The top holder (7) can drive the piston component (9) to extend into the piston hole (8). The piston component (9) is provided with a driven assembly for driving the push plate (6) to approach the template (3) when the piston component (9) extends into the piston hole (8) and reaches a preset stroke, and a reset assembly for resetting the piston component (9) when the top holder (7) is away from the piston component (9).

2. A plastic cup mold with quick demolding according to claim 1, characterized in that: The driven assembly comprises a first protruding ring (10) provided on the piston component (9), which is located on the side of the push plate (6) away from the template (3) and has a preset interval with the push plate (6).

3. A plastic cup mold that can be quickly demolded according to claim 2, characterized in that: The first protruding ring (10) is movably arranged on the piston component (9), and the first protruding ring (10) is provided with an adjusting structure between the piston component (9) for adjusting the size of the preset interval.

4. A plastic cup mould which can be quickly demoulded according to claim 3, characterised in that: The adjusting structure comprises a threaded segment (11) provided on the piston component (9) and a threaded hole (12) provided on the first protruding ring (10) and screwing with the threaded segment (11).

5. A plastic cup mold that can be quickly demolded according to claim 1, characterized in that: The reset assembly comprises a second protruding ring (13) fixedly arranged on the piston component (9) and located between the push plate (6) and the template (3), and a first elastic member (14) arranged between the second protruding ring (13) and the template (3).

6. A plastic cup mold that can be quickly demolded according to claim 1, characterized in that: The piston component (9) comprises a cylinder (901) penetrating through the push plate (6) and a piston rod (902) telescopically arranged opposite to the cylinder (901), and the end of the piston rod (902) exposed from the cylinder (901) forms a piston end (903). The driven assembly is arranged on the guide rod, and the second elastic member is arranged between the cylinder (901) and the piston rod (902) to keep the piston rod (902) in the extended state.

7. A plastic cup mold that can be quickly demolded according to claim 1, characterized in that: The exhaust structure comprises exhaust grooves (15) in communication with the inner wall of the piston hole (8) and the top surface of the punch (4) respectively, and the exhaust grooves (15) are provided with air pins (16) at the openings on the top surface of the punch (4).

8. A plastic cup mold that can be quickly demolded according to claim 7, characterized in that: There are n exhaust grooves (15), and one opening of the exhaust groove (15) is provided at the center of the top surface of the punch (4), and n-1 openings of the exhaust grooves (15) are uniformly and interval provided around the edge of the end surface of the punch (4).

9. A plastic cup mold that can be quickly demolded according to claim 1, characterized in that: The pushing assembly comprises a pair of push rods (17) protruding from the push plate (6), the end of the push rod (17) penetrates through the template (3) and is flush with the end of the template (3) facing the punch (4), and the push rod (17) is sleeved with a third elastic member (18) for driving the push plate (6) to move away from the template (3).

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