A medical device shell injection mold without ejector pin inclined top demolding core pulling mechanism
By using a pinless, angled ejector core-pulling mechanism, which utilizes a linked core-pulling structure and high-pressure gas to drive the ejector block, the problems of large space occupation and complex structure of injection molds are solved, thereby achieving mold miniaturization and cost reduction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHEJIANG KAIHUA MOLDS
- Filing Date
- 2026-04-10
- Publication Date
- 2026-06-02
AI Technical Summary
In existing injection molds, the ejection structure occupies a large space and has a complex structure, which leads to an increase in mold height, equipment cost, and development cost.
The ejector core-pulling mechanism adopts a pinless angled ejector, which uses a linkage core-pulling structure and high-pressure gas to push the push block to eject the plastic part. It eliminates the mold feet, ejector plates, straight ejector pins and oil cylinders in traditional molds. The core-pulling and demolding of the angled pillars and angled holes are achieved by the cooperation of the wedge and the slider.
The mold has a simple structure and reduced size, which lowers equipment investment and development costs, and is suitable for production on smaller tonnage injection molding machines.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention relates to injection molds, and more particularly to a core-pulling mechanism for ejector pins and angled ejectors in injection molds for medical device housings. Background Technology
[0002] After injection molding a plastic part, the mold typically uses an ejector mechanism to eject the part from the moving platen of the mold. Existing ejector mechanisms usually employ a hydraulic cylinder and an ejector plate. A straight ejector pin is mounted on the ejector plate, and the hydraulic cylinder drives the ejector plate, which in turn drives the straight ejector pin to eject the plastic part. If the injection-molded plastic part has a protruding inclined pillar with an inclined hole, a slide block is also needed on the ejector plate. An inclined ejector pin is mounted on the slide block, with its bottom slidingly engaging with the slide block. As the ejector plate pushes the slide block and the inclined ejector pin upwards, the inclined ejector pin slides along the slide block and gradually withdraws. The design incorporates inclined pillars and holes at the bottom of the plastic part, but this structure has several drawbacks: First, the ejection structure using an ejector plate requires mold feet between the moving platen and the lower platen. These mold feet create running space for the ejector plate. The mold feet and ejector plate occupy a significant amount of mold space, increasing the overall height and volume of the injection mold. Consequently, a larger tonnage injection molding machine is needed to operate the mold, increasing equipment costs. Second, the addition of mold feet, ejector plates, straight ejector pins, inclined ejector pins, and hydraulic cylinders makes the structure more complex, leading to higher mold development costs. Summary of the Invention
[0003] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a core-pulling mechanism for injection molds of medical device housings that occupies little mold space, reduces mold volume, has a simple structure, and lowers mold development costs.
[0004] The technical solution of the present invention for a core-pulling mechanism without ejector pins in an injection mold for a medical device housing is as follows: It includes an upper plate and a lower plate. A fixed template is provided under the upper plate, and a movable template is provided on the lower plate. A mold cavity is formed between the movable template and the fixed template, and a plastic part is injection molded in the mold cavity. A protruding inclined post is provided under the plastic part, and an inclined hole is formed in the inclined post. An inclined guide hole and a mounting hole are formed in the movable template. A lower core-pulling rod is provided in the inclined guide hole. The upper end of the lower core-pulling rod cooperates with the inclined post and the inclined hole. The lower end of the lower core-pulling rod is provided with a linkage core-pulling structure for driving the lower core-pulling rod downward to pull the core. An air inlet is provided in the moving template, an air blowing seat is provided in the mounting hole, a limiting plate is provided in the air blowing seat, and a through hole is provided in the limiting plate. The interior of the air blowing seat is divided into an upper cavity and a lower cavity by the limiting plate. A push block is provided in the upper cavity, and a push rod is provided below the push block. An air blowing groove is provided on the side wall of the push rod. The air inlet communicates with the lower cavity, and the lower cavity communicates with the upper cavity through the air blowing groove. A baffle is provided through the through hole at the lower end of the push rod, and a nut is provided below the baffle. The nut is threadedly engaged with the lower end of the push rod. A first spring is provided on the outer wall of the push rod. The upper end of the first spring contacts the limiting plate, and the lower end of the first spring contacts the baffle.
[0005] Furthermore, the linkage core-pulling structure includes a wedge on the side wall of the fixed template, a first inclined guide rail below the wedge, a groove in the moving template located below the lower core-pulling rod, a slider in the groove, a first inclined guide groove and a second inclined guide groove on the slider, the first inclined guide groove cooperating with the first inclined guide rail, and a second inclined guide rail at the bottom of the lower core-pulling rod, the second inclined guide rail cooperating with the second inclined guide groove.
[0006] Furthermore, the bottom of the slider is provided with a first positioning groove, a second positioning groove and a third positioning groove, and a first positioning pin and a second positioning pin are provided in the lower cover plate, with a second spring respectively provided at the bottom of the first positioning pin and the second positioning pin.
[0007] Furthermore, the upper cavity cross-section is inverted trapezoidal, and the corresponding push block cross-section is also inverted trapezoidal.
[0008] Furthermore, the air-blowing seat is in two or more sets.
[0009] The beneficial effects of the ejector-less inclined ejector core-pulling mechanism for injection molds of medical device housings of the present invention are as follows: It eliminates the ejection structures such as mold feet, ejector plates, straight ejector pins, inclined ejector pins, and hydraulic cylinders in traditional molds, and adopts a linked core-pulling structure to achieve core-pulling and demolding of inclined pillars and inclined holes. High-pressure gas is used to push the push block to achieve the ejection of plastic parts, reducing the number of mold parts, making the mold structure simpler, and reducing the overall height and volume of the mold. It can be produced using injection molding machines with smaller tonnage, effectively reducing equipment investment costs and mold development costs. Attached Figure Description
[0010] Figure 1This is a schematic diagram of the mold closing state structure of a core-pulling mechanism for ejector pinless inclined ejector core-pulling of a medical device housing injection mold according to the present invention; Figure 2 This is a schematic diagram of the linkage core-pulling structure driving the lower core-pulling rod to pull the core downwards. Figure 3 This is a schematic diagram of the structure in which the pusher pushes the plastic part upwards; Figure 4 yes Figure 2 A magnified view of part A; Figure 5 yes Figure 3 A magnified view of part B.
[0011] In the diagram, 1. Upper cover plate; 2. Lower cover plate; 3. Fixed template; 4. Moving template; 5. Plastic part; 6. Inclined column; 7. Inclined hole; 8. Inclined guide hole; 9. Mounting hole; 10. Lower core-pulling rod; 11. Air inlet; 12. Air blowing seat; 13. Limiting plate; 14. Through hole; 15. Upper cavity; 16. Lower cavity; 17. Push block; 18. Push rod; 19. Air blowing groove; 20. Baffle; 21. Nut; 22. First spring; 23. Inclined wedge; 24. First inclined guide rail; 25. Slide groove; 26. Slider; 27. First inclined guide groove; 28. Second inclined guide groove; 29. Second inclined guide rail; 30. First positioning groove; 31. Second positioning groove; 32. Third positioning groove; 33. First positioning pin; 34. Second positioning pin; 35. Second spring. Detailed Implementation
[0012] To enable those skilled in the art to better understand the technical solutions of the present invention, preferred embodiments of the present invention are described below in conjunction with specific examples. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote elements with the same or similar functions throughout. However, it should be understood that the drawings are for illustrative purposes only and should not be construed as limiting the present invention. To better illustrate this embodiment, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable for those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings. The positional relationships described in the drawings are for illustrative purposes only and should not be construed as limiting the present invention.
[0013] It should be noted that the terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this invention are intended to cover non-exclusive inclusion. The terms "set," "equipped with," "installed," "connected," and "connected" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral construction; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two mechanisms, elements, or components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0014] In the description of this invention, it should be understood that the terms "upper," "lower," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the mechanism or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. The terms "first" and "second" are also used only for the sake of brevity in description and do not indicate or imply relative importance.
[0015] To further illustrate the content, features, and effects of this invention, the invention will be described in detail below with reference to the accompanying drawings and examples, but this should not be construed as limiting the invention.
[0016] This invention relates to a pinless, angled ejector core-pulling mechanism for injection molds used to mold the outer casing of medical devices, such as... Figure 1 — Figure 5As shown, the system includes an upper cover plate 1 and a lower cover plate 2. A fixed template 3 is provided under the upper cover plate 1, and a movable template 4 is provided on the lower cover plate 2. A mold cavity is formed between the movable template 4 and the fixed template 3, and a plastic part 5 is injection molded in the mold cavity. A protruding inclined column 6 is provided under the plastic part 5, and an inclined hole 7 is provided in the inclined column 6. An inclined guide hole 8 and a mounting hole 9 are provided in the movable template 4. A lower core-pulling rod 10 is provided in the inclined guide hole 8. The upper end of the lower core-pulling rod 10 cooperates with the inclined column 6 and the inclined hole 7. The lower end of the lower core-pulling rod 10 is provided with a linkage core-pulling structure for driving the lower core-pulling rod 10 to pull the core downward. An air inlet 11 is provided in the movable template 4, and an air blowing seat 12 is provided in the mounting hole 9. A limiting plate 13 is provided in the middle, and a through hole 14 is provided in the limiting plate 13. The interior of the air blowing seat 12 is divided into an upper cavity 15 and a lower cavity 16 by the limiting plate 13. A push block 17 is provided in the upper cavity 15, and a push rod 18 is provided below the push block 17. An air blowing groove 19 is provided on the side wall of the push rod 18. The air inlet 11 communicates with the lower cavity 16, and the lower cavity 16 communicates with the upper cavity 15 through the air blowing groove 19. A baffle 20 is provided through the through hole 14 at the lower end of the push rod 18. A nut 21 is provided below the baffle 20. The nut 21 is threadedly engaged with the lower end of the push rod 18. A first spring 22 is provided on the outer wall of the push rod 18. The upper end of the first spring 22 contacts the limiting plate 13, and the lower end of the first spring 22 contacts the baffle 20.
[0017] Furthermore, the linked core-pulling structure includes a wedge 23 on the side wall of the fixed template 3, a first inclined guide rail 24 below the wedge 23, a groove 25 at the lower part of the moving template 4 below the lower core-pulling rod 10, a slider 26 in the groove 25, a first inclined guide groove 27 and a second inclined guide groove 28 on the slider 26, the first inclined guide groove 27 cooperating with the first inclined guide rail 24, and a second inclined guide rail 29 at the bottom of the lower core-pulling rod 10, the second inclined guide rail 29 cooperating with the second inclined guide groove 28. The first inclined guide groove 27 and the second inclined guide groove 28 can be I-shaped grooves or dovetail grooves, and the first inclined guide rail 24 and the second inclined guide rail 29 are corresponding I-shaped or dovetail-shaped slide rails.
[0018] Furthermore, the bottom of the slider 26 is provided with a first positioning groove 30, a second positioning groove 31 and a third positioning groove 32, and a first positioning pin 33 and a second positioning pin 34 are provided in the lower cover plate 2. The bottom of the first positioning pin 33 and the second positioning pin 34 are respectively provided with a second spring 35. When the slider 26 is closed and reset, the first positioning pin 33 is engaged in the first positioning groove 30, and the second positioning pin 34 is engaged in the second positioning groove 31. When the slider 26 moves outward, it overcomes the elastic force of the second spring 35 and pushes the first positioning pin 33 and the second positioning pin 34 downward. When the second positioning groove 31 corresponds to the first positioning pin 33 and the third positioning groove 32 corresponds to the second positioning pin 34, the second spring 35, under the action of elastic restoring force, pushes the first positioning pin 33 upward and engages it in the second positioning groove 31, and pushes the second positioning pin 34 upward and engages it in the third positioning groove 32, so that the slider 26 is positioned. The cooperation of the two sets of positioning pins and the three sets of positioning grooves realizes the precise positioning of the slider 26 in both the closed and fully open mold states. On the one hand, it can ensure the accurate and reliable core pulling action of the lower core pulling rod 10. On the other hand, it can ensure that the first inclined guide rail 24 can be accurately inserted into the first inclined guide groove 27 when the wedge 23 is closed, ensuring that the slider 26 can be reset smoothly.
[0019] Furthermore, the upper cavity 15 has an inverted trapezoidal cross-section, and the corresponding push block 17 also has an inverted trapezoidal cross-section. The inverted trapezoidal cross-section of the upper cavity 15 cooperates with the push block 17 to ensure that the push block 17 can smoothly fall into the upper cavity 15 when it is reset downwards.
[0020] Furthermore, there are two or more sets of air-blowing seats 12. The arrangement of two or more sets of air-blowing seats 12 at different positions on the bottom of the plastic part 5 can ensure that the plastic part 5 is subjected to uniform force during ejection, and avoid deformation or damage to the plastic part 5.
[0021] This invention discloses a pinless, angled ejector core-pulling mechanism for injection molds of medical device housings. After the plastic part 5 (which can be the medical device housing) is injection molded, the injection molding machine drives the lower platen 2 to move downwards. The lower platen 2 drives the moving template 4, slider 26, lower core-pulling rod 10, air blower 12, and plastic part 5 to move downwards together, while the upper platen 1, fixed template 3, and wedge 23 remain stationary. This allows the mold to gradually open from the fixed template 3 and moving template 4. Simultaneously, the first inclined guide rail 24 of the wedge 23 engages with the first inclined guide groove 27 of the slider 26, driving the slider 26 along the guide rail... The groove 25 moves outward, and the slider 26 cooperates with the second inclined guide rail 29 at the bottom of the lower core-pulling rod 10 through the second inclined guide groove 28, driving the lower core-pulling rod 10 to move downward along the inclined guide hole 8, so that the upper end of the lower core-pulling rod 10 pulls out the inclined column 6 and inclined hole 7 of the plastic part 5 downward. Then, the high-pressure air pump (the high-pressure air pump can be set outside the mold and connected to the air inlet 11 through the pipeline) delivers high-pressure gas through the air inlet 11 to the lower cavity 16 of the air blowing seat 12. The high-pressure gas enters the upper cavity 15 through the air blowing groove 19 of the push rod 18. Since the bottom of the push block 17 is in contact with the limiting plate 13, the high-pressure gas pushes the upper cavity 15. Push block 17 moves upward, driving push rod 18 to move upward along through hole 14. Push rod 18 drives nut 21 and baffle 20 to move upward against the elastic force of first spring 22, while push block 17 pushes plastic part 5 upward. As push block 17 moves upward, a gap is left between the outer wall and bottom of push block 17 and the inner wall of upper cavity 15 of air blowing seat 12. High-pressure gas can be blown out through this gap. With the assistance of high-pressure gas, plastic part 5 is ejected from moving mold plate 4. After demolding is completed, high-pressure gas stops entering, and the elastic restoring force of first spring 22 pushes baffle 20 and nut 21 downward. In position, the baffle 20 drives the push rod 18 and the push block 17 to move downward, so that the push block 17 is re-engaged into the upper cavity 15 and fits against the limiting plate 13. The upper surface of the push block 17 is flush with the bottom surface of the mold cavity of the moving template 4. The injection molding machine drives the moving template 4, the slider 26, the lower core-pulling rod 10, and the air-blowing seat 12 to close the mold upward together. The first inclined guide rail 24 of the wedge 23 is inserted into the first inclined guide groove 27 of the slider 26, pushing the slider 26 to reset inward. The second inclined guide groove 28 of the slider 26 cooperates with the second inclined guide rail 29 at the bottom of the lower core-pulling rod 10, driving the lower core-pulling rod 10 to reset upward, waiting for the next injection molding.
[0022] Although the embodiments of this application disclose the above-described methods, the content is merely an implementation method adopted for ease of understanding. Any person skilled in the art should understand that any modifications and changes in the form and details of the implementation can be made without departing from the spirit and scope of the present invention. However, the scope of patent protection of the present invention shall still be determined by the scope defined in the appended claims.
Claims
1. A core-pulling mechanism for ejector-free slanted ejector of a medical device housing injection mold, comprising an upper plate (1) and a lower plate (2), wherein a fixed template (3) is provided under the upper plate (1), and a movable template (4) is provided on the lower plate (2), forming a mold cavity between the movable template (4) and the fixed template (3), wherein a plastic part (5) is injection molded in the mold cavity, and a protruding slanted post (6) is provided under the plastic part (5), wherein a slanted hole (7) is formed in the slanted post (6), characterized in that: The moving template (4) has an inclined guide hole (8) and a mounting hole (9). A lower core-pulling rod (10) is provided in the inclined guide hole (8). The upper end of the lower core-pulling rod (10) cooperates with the inclined column (6) and the inclined hole (7). The lower end of the lower core-pulling rod (10) is provided with a linkage core-pulling structure for driving the lower core-pulling rod (10) to pull the core downward. An air inlet hole (11) is provided in the moving template (4). An air blowing seat (12) is provided in the mounting hole (9). A limiting plate (13) is provided in the air blowing seat (12). A through hole (14) is provided in the limiting plate (13). The interior of the air blowing seat (12) is divided into an upper cavity (15) and a lower cavity (16) by the limiting plate (13). The upper cavity (15) A push block (17) is provided in the middle, and a push rod (18) is provided under the push block (17). An air blowing groove (19) is opened on the side wall of the push rod (18). The air inlet (11) is connected to the lower cavity (16). The lower cavity (16) is connected to the upper cavity (15) through the air blowing groove (19). The lower end of the push rod (18) passes through the through hole (14) and a baffle (20) is provided. A nut (21) is provided under the baffle (20). The nut (21) is threadedly engaged with the lower end of the push rod (18). A first spring (22) is provided on the outer wall of the push rod (18). The upper end of the first spring (22) is in contact with the limiting plate (13), and the lower end of the first spring (22) is in contact with the baffle (20).
2. The ejector-less, angled ejector core-pulling mechanism for injection molds of medical device housings as described in claim 1, characterized in that: The linkage core-pulling structure includes a wedge (23) set on the side wall of the fixed template (3), a first inclined guide rail (24) set below the wedge (23), a sliding groove (25) opened at the lower part of the moving template (4) located below the lower core-pulling rod (10), a slider (26) set in the sliding groove (25), a first inclined guide groove (27) and a second inclined guide groove (28) set on the slider (26), the first inclined guide groove (27) cooperates with the first inclined guide rail (24), and a second inclined guide rail (29) is set at the bottom of the lower core-pulling rod (10), the second inclined guide rail (29) cooperates with the second inclined guide groove (28).
3. The ejector-less, angled ejector core-pulling mechanism for injection molds of medical device housings as described in claim 2, characterized in that: The slider (26) is provided with a first positioning groove (30), a second positioning groove (31) and a third positioning groove (32) at the bottom. A first positioning pin (33) and a second positioning pin (34) are provided in the lower cover plate (2). A second spring (35) is provided at the bottom of the first positioning pin (33) and the second positioning pin (34).
4. The ejector-less, angled ejector core-pulling mechanism for injection molds of medical device housings as described in claim 1, characterized in that: The upper cavity (15) has an inverted trapezoidal cross section, and the corresponding push block (17) has an inverted trapezoidal cross section.
5. The ejector-less, angled ejector core-pulling mechanism for injection molds of medical device housings as described in claim 1, characterized in that: The air-blowing seat (12) consists of two or more sets.