A secondary ejection mechanism for an injection mold

Abstract

The utility model provides a secondary ejection mechanism of injection mould belongs to mould technical field. The utility model provides an improved scheme for the problems of complex structure, poor stability and large space occupation of the existing secondary ejection mechanism. The mechanism includes B plate and A plate, A plate sliding connection is in the top of B plate, is equipped with former and rear die kernel and forms the mould cavity. The demoulding assembly is located at the bottom of B plate, and includes the ejector pin plate and the ejector pin main body. The secondary ejection assembly is symmetrically arranged at both sides of B plate, and contains the outer sleeve plate fixed to the bottom plate, and the inner slide plate slides in the outer sleeve plate. When demoulding, the sliding block is stretched out and is clamped into the recess under the compression spring, drives the inner slide plate and B plate synchronous movement and completes the first ejection, when the sliding block contacts the trapezoidal groove inclined section, the sliding block is retracted and is separated from the recess, and the ejector pin main body moves alone and realizes the second ejection. The demoulding action of the utility model is stable and reliable, effectively reduces the demoulding resistance of plastic parts, avoids the deformation damage of plastic parts, improves product quality and production efficiency.

Description

Technical Field

[0001] This utility model relates to the field of mold technology, and in particular to a secondary ejection mechanism for injection molds. Background Technology

[0002] In injection molding, demolding is the crucial step in removing the molded plastic part from the mold. For some simple-shaped plastic parts with low demolding resistance, a single ejection mechanism can usually meet the demolding requirements. However, with the continuous development of the plastic products industry, the requirements for the shape and structure of plastic parts are becoming increasingly stringent. Many plastic parts have complex shapes, deep cavity structures, or internal undercuts, which increases the adhesion between the plastic part and the mold during demolding, and consequently increases the demolding resistance.

[0003] Traditional single-ejection mechanisms often have many limitations when dealing with such complex plastic parts. On the one hand, excessive single ejection force can easily lead to deformation and damage of the plastic part, affecting its appearance and dimensional accuracy, and reducing product quality. On the other hand, for plastic parts with undercut structures, single ejection may not be able to smoothly remove the plastic part from the mold, which may cause the plastic part to get stuck in the mold, resulting in mold damage or production interruption, affecting production efficiency and mold life.

[0004] To address these issues, a secondary ejection mechanism was developed. This mechanism applies ejection force in stages: first, a preliminary ejection separates the plastic part from the mold, reducing demolding resistance; then, a secondary ejection completely removes the part from the mold. This method effectively reduces the stress on the plastic part during demolding, preventing damage, and better accommodates the demolding needs of complex-shaped parts.

[0005] However, existing secondary ejection mechanisms still have some shortcomings in their structural design, such as complex structure, poor stability, and large space occupation, which affect their application effect in actual production. Therefore, developing a secondary ejection mechanism for injection molds that is simple in structure, stable and reliable, and has good demolding effect is of great practical significance. Utility Model Content

[0006] The purpose of this invention is to address the shortcomings of existing secondary ejection mechanisms in terms of structural design, such as complex structure, poor stability, and large space occupation, which affect their application effect in actual production. Therefore, this invention proposes a secondary ejection mechanism for injection molds.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A secondary ejection mechanism for an injection mold includes a B plate and an A plate. The A plate is slidably connected to the top of the B plate. A front mold core is fixedly installed at the bottom of the A plate, and a rear mold core is fixedly installed at the top of the B plate. The front mold core and the rear mold core cooperate to form a mold cavity. A panel is fixedly installed at the top of the A plate. A demolding assembly, located at the bottom of plate B, includes an ejector plate and an ejector body fixedly mounted on the ejector plate, the ejector body extending into the interior of the rear mold core; The secondary ejection assembly is symmetrically arranged on both sides of the B plate, including an outer plate, an inner slide plate, and a slider. The outer plate is fixedly installed on the base plate, and the inner slide plate is slidably connected to the inside of the outer plate. The outer plate has a trapezoidal groove, and the inner slide plate has a groove. The slider is slidably arranged in the first mounting groove of the ejector plate and is connected to a compression spring. During demolding, the slider extends under the action of the compression spring and gets into the groove, driving the inner slide plate and B plate to move synchronously to achieve the first ejection. When the slider contacts the inclined section of the trapezoidal groove, the slider retracts and disengages from the groove, and the ejector pin body moves independently to achieve the second ejection.

[0008] In one possible design, the demolding assembly further includes a pad and a plurality of return springs, the pad being fixedly mounted on the bottom of plate B, the ejector plate being disposed at the bottom of the pad, and the return springs being disposed between the ejector plate and the pad.

[0009] In one possible design, the design also includes square irons and a base plate, with two square irons fixedly installed on the bottom sides of the pad, and the base plate fixedly installed on the bottom of the square irons, with the bottom of the ejector plate abutting against the top of the base plate.

[0010] In one possible design, the secondary ejection assembly further includes a second mounting groove, a mounting block, and a limiting plate. The second mounting groove is opened on one side of the B plate, the mounting block is fixedly installed inside the second mounting groove, the limiting plate is fixedly installed on one side of the mounting block, and the inner sliding plate is fixedly installed at the bottom of the limiting plate.

[0011] In one possible design, two symmetrical compression springs are provided between one end of the slider and the inner wall of one side of the first mounting groove, and the outer end of the slider is arc-shaped to match the contour of the trapezoidal groove and the recess.

[0012] In one possible design, guide posts and guide sleeves are also included. The guide posts are fixedly installed at the four bottom corners of plate A, and the guide sleeves are fixedly installed at the four top corners of plate B. The guide posts are slidably connected to the inside of the guide sleeves.

[0013] In one possible design, the trapezoidal groove includes a vertical section and an inclined section, wherein the vertical section is used to guide the slider and the inclined section is used to force the slider to retract inward.

[0014] In one possible design, the return springs are multiple and evenly arranged between the ejector plate and the pad, and are used to automatically reset the ejector plate after ejection.

[0015] In one possible design, an upper positioning block and a lower positioning block are also included. The upper positioning block is fixedly installed at the bottom four corners of plate A, and the lower positioning block is fixedly installed at the top four corners of plate B. The lower positioning block and the upper positioning block are mated together during mold closing to ensure accuracy.

[0016] In this application, when demolding is required, the B plate and the pad are separated first, so that the front mold core and the rear mold core are separated, and the guide post slides inside the guide sleeve to ensure the stability of the device movement. The setting of the lower positioning block and the upper positioning block ensures the stability of the mold closing. Next, the ejector plate drives the ejector body to move, and the ejector plate squeezes the reset spring. At the same time, the slider located inside the first mounting groove is always in the extended state due to the elastic force of the compression spring. The slider is inside the groove and can drive the inner slide plate to move synchronously. Since the trapezoidal groove has a vertical section and an inclined section, the slider first drives the inner slide plate to move, and the inner slide plate drives the limit plate and the mounting block to move, thereby making the B plate and the ejector body move synchronously. When the slider presses against the inclined section of the trapezoidal groove, the slider squeezes the compression spring and retracts inward. It no longer drives the B plate to move, but only drives the ejector body to move, realizing the function of secondary ejection.

[0017] Beneficial effects: During the demolding process, the B plate and the backing plate are separated first, allowing the front mold core and the rear mold core to detach. Simultaneously, the guide pillars slide inside the guide sleeve. This design provides precise guidance for the opening and closing of the mold, ensuring the stability of the device's movement and effectively avoiding demolding failures caused by mold movement deviations, thus improving the reliability of the demolding process. The lower and upper positioning blocks further ensure the stability of mold closing, ensuring that the mold can accurately reset during multiple opening and closing processes, improving mold lifespan and product quality.

[0018] The secondary ejection assembly design utilizes an ejector plate to move the ejector body, while the slider remains extended under the force of a compression spring. In the initial demolding stage, the slider moves the inner slide synchronously, causing the B-plate and ejector body to move synchronously, achieving initial ejection. When the slider contacts the inclined section of the trapezoidal groove, it compresses the spring and retracts, ceasing to move the B-plate and only moving the ejector body to complete the secondary ejection. This secondary ejection method better adapts to the demolding requirements of complex-shaped plastic parts, effectively preventing damage during demolding due to excessive primary ejection force, and improving the molding quality of the plastic parts.

[0019] The entire secondary ejection mechanism features a compact layout with well-coordinated components, achieving complex functions within a limited space. For example, the secondary ejection components are cleverly positioned on both sides of the B plate, utilizing the synergistic action of trapezoidal grooves, inner slide plates, and sliders to complete the secondary ejection action. This design does not occupy excessive mold space while ensuring stable functionality, thus facilitating mold miniaturization and integrated design.

[0020] Multiple return springs installed between the ejector plate and the backing plate automatically reset the ejector plate and ejector body after the ejection action is completed, preparing for the next demolding. This reset method is simple and reliable, requiring no additional complex drive devices, thus reducing the manufacturing cost and maintenance difficulty of the mold. Attached Figure Description

[0021] Figure 1 This is a three-dimensional structural diagram of a secondary ejection mechanism for an injection mold proposed in this utility model. Figure 2 This is an exploded view of a secondary ejection mechanism for an injection mold proposed in this utility model. Figure 3 This is a three-dimensional structural diagram of plate B and bottom plate in the secondary ejection mechanism of an injection mold proposed in this utility model. Figure 4 This is an exploded view of the slider and outer sleeve plate in the secondary ejection mechanism of an injection mold proposed in this utility model.

[0022] In the diagram: 1. Base plate; 2. Square iron; 3. Pad plate; 4. Front panel; 5. A plate; 6. B plate; 7. Outer plate; 8. Limiting plate; 9. Guide post; 10. Lower positioning block; 11. Upper positioning block; 12. Front mold core; 13. Rear mold core; 14. Guide sleeve; 15. First mounting groove; 16. Trapezoidal groove; 17. Ejector plate; 18. Return spring; 19. Ejector body; 20. Second mounting groove; 21. Mounting block; 22. Inner sliding plate; 23. Slider; 24. Compression spring; 25. Groove. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0024] In one embodiment: Refer to Figure 1-4The secondary ejection mechanism is mainly composed of a B plate 6 and an A plate 5 forming the basic frame structure. The A plate 5 is slidably connected to the top of the B plate 6, and the two achieve a stable sliding fit through guide pillars 9 and guide sleeves 14. Specifically, guide pillars 9 are fixedly installed at the four bottom corners of the A plate 5, and guide sleeves 14 are fixedly installed at the corresponding positions at the four top corners of the B plate 6. The guide pillars 9 are inserted into the guide sleeves 14 to form a sliding guide structure. The front mold core 12 is fixedly installed at the bottom center of the A plate 5, and the rear mold core 13 is fixedly installed at the corresponding position at the top center of the B plate 6. The two fit together to form a complete mold cavity. A panel 4 is fixedly installed at the top of the A plate 5, forming the upper structure of the mold.

[0025] To ensure mold closing accuracy, upper positioning blocks 11 are fixedly installed at the four bottom corners of plate A 5, and lower positioning blocks 10 are fixedly installed at the corresponding positions at the four top corners of plate B 6. During mold closing, the upper positioning blocks 11 and lower positioning blocks 10 are precisely aligned to prevent mold displacement. A demolding assembly is provided at the bottom of plate B 6, which consists of a backing plate 3, an ejector plate 17, return springs 18, and ejector bodies 19. The backing plate 3 is located directly below plate B 6, and the two are fixedly connected by bolts. The ejector plate 17 is located below the backing plate 3, and multiple return springs 18 are evenly arranged between the two to form an elastic return structure. Multiple ejector bodies 19 are fixedly installed on the top of the ejector plate 17. The ejector bodies 19 extend upward through the backing plate 3 and plate B 6, and finally enter the interior of the rear mold core 13 to eject the molded plastic part.

[0026] The support structure of the demolding assembly consists of square iron 2 and base plate 1. Square iron 2 is symmetrically fixed on both sides of the bottom of the pad plate 3, and the bottom of the two square iron 2 is fixedly connected to the same base plate 1 to form a stable frame structure. The bottom of the ejector plate 17 abuts against the top of the base plate 1, limiting the downward limit position of the ejector plate 17.

[0027] The secondary ejection components are arranged on both sides of plate B6, with one set on each side. Taking one side as an example, a second mounting groove 20 is opened on the side of plate B6, and a mounting block 21 is fixedly installed inside. A limiting plate 8 is fixedly installed on the outside of the mounting block 21, and an inner sliding plate 22 is fixedly installed at the bottom of the limiting plate 8. An outer plate 7 is fixedly installed at the corresponding position on the bottom plate 1, and the inner sliding plate 22 is slidably connected inside the outer plate 7. Two symmetrical trapezoidal grooves 16 are opened on the side of the outer plate 7, each trapezoidal groove 16 consisting of a vertical section and an inclined section. A groove 25 is opened on the bottom of the side of the inner sliding plate 22 for use with the slider 23.

[0028] The working process is as follows: When demolding is required, the mold opening action separates plate B6 from pad 3, causing the front mold core 12 to separate from the rear mold core 13. The guide post 9 slides within the guide sleeve 14 to ensure smooth movement. The lower positioning block 10 separates from the upper positioning block 11, completing the initial mold opening. At this time, the ejector plate 17 remains stationary under the action of the return spring 18, and the ejector body 19 has not yet moved.

[0029] Then, the ejection action is performed, and the external ejection device pushes the ejector plate 17 upward. The ejector plate 17 compresses the return spring 18, simultaneously driving the ejector body 19 upward. Since the slider 23 is always in the extended state under the action of the compression spring 24, its outer end is engaged in the groove 25 of the inner slide plate 22. Therefore, when the ejector plate 17 moves, it drives the inner slide plate 22 to move upward synchronously through the slider 23. The inner slide plate 22 drives the B plate 6 upward through the limiting plate 8 and the mounting block 21, realizing the initial ejection of the plastic part.

[0030] When the inner slide plate 22 moves to the inclined section of the trapezoidal groove 16, the outer arc surface of the slider 23 contacts the inclined surface of the trapezoidal groove 16. As ejection continues, the inclined surface of the trapezoidal groove 16 forces the slider 23 to compress the compression spring 24 inward, and finally the slider 23 is completely retracted into the first mounting groove 15, disengaging from the inner slide plate 22. At this time, the B plate 6 stops moving, while the ejector plate 17 continues to drive the ejector body 19 to move upward, realizing the secondary ejection of the plastic part.

[0031] During reset, the external ejection device releases its ejection force, and the ejector plate 17 moves downward under the action of the reset spring 18. The slider 23 extends again under the action of the compression spring 24, and when it reaches the vertical section of the trapezoidal groove 16, the outer end of the slider 23 enters the internal space of the outer sleeve plate 7. Continuing downward, the outer end of the slider 23 contacts the side of the inner slide plate 22, pushing the inner slide plate 22 downward, ultimately resetting plate B 6. During mold closing, plate A 5 moves downward, and the lower positioning block 10 precisely aligns with the upper positioning block 11, completing mold closure.

[0032] This mechanism effectively reduces the demolding resistance of complex plastic parts through a staged ejection design. The initial ejection partially separates the plastic part from the mold, reducing adhesion; the secondary ejection ensures the plastic part is completely removed from the mold, avoiding deformation or damage caused by excessive force in a single ejection. The special design of the trapezoidal groove 16 enables automatic switching of the ejection process without the need for additional control devices, resulting in a simple and reliable structure. The guide pillar and guide sleeve 914 structure ensures the stability of mold movement, while the upper and lower positioning blocks 1011 ensure mold closing accuracy. The overall structure is compact, occupies little space, and is suitable for injection molding production of various complex plastic parts.

[0033] This application can be used in the field of mold making, or in other fields applicable to this application.

[0034] In another embodiment: Reference Figure 1-4 A secondary ejection mechanism for an injection mold, applicable in the mold industry, is described. A first mounting groove 15 is formed on the side of the ejector plate 17, through which a slider 23 slides. Two symmetrically arranged compression springs 24 are positioned between one end of the slider 23 and the side wall of the first mounting groove 15, ensuring the slider 23 always maintains an outward extension tendency. The outer end of the slider 23 is designed in an arc shape, matching the arc transition surface of the trapezoidal groove 16 and the recess 25.

[0035] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A secondary ejection mechanism of an injection mold characterized by comprising: include: Plate B (6) and Plate A (5), Plate A (5) is slidably connected to the top of Plate B (6), a front mold core (12) is fixedly installed at the bottom of Plate A (5), a rear mold core (13) is fixedly installed at the top of Plate B (6), the front mold core (12) and the rear mold core (13) cooperate to form a mold cavity, and a panel (4) is fixedly installed at the top of Plate A (5). The demolding assembly is located at the bottom of plate B (6) and includes an ejector plate (17) and an ejector body (19) fixedly mounted on the ejector plate (17), the ejector body (19) extending into the interior of the rear mold core (13); The secondary ejection assembly is symmetrically arranged on both sides of the B plate (6), including an outer plate (7), an inner slide plate (22) and a slider (23). The outer plate (7) is fixedly installed on the base plate (1), and the inner slide plate (22) is slidably connected to the inside of the outer plate (7). The outer plate (7) has a trapezoidal groove (16), and the inner slide plate (22) has a groove (25). The slider (23) is slidably arranged in the first mounting groove (15) of the ejector plate (17) and connected to the compression spring (24). During demolding, the slider (23) extends under the action of the compression spring (24) and gets stuck in the groove (25), driving the inner slide plate (22) and the B plate (6) to move synchronously to achieve the first ejection. When the slider (23) contacts the inclined section of the trapezoidal groove (16), the slider (23) retracts and gets out of the groove (25), and the ejector pin body (19) moves alone to achieve the second ejection.

2. The secondary ejection mechanism of an injection mold according to claim 1, characterized in that, The demolding assembly also includes a pad (3) and a plurality of return springs (18). The pad (3) is fixedly installed on the bottom of the B plate (6). The ejector plate (17) is located at the bottom of the pad (3). The return springs (18) are located between the ejector plate (17) and the pad (3).

3. The secondary ejection mechanism of an injection mold according to claim 2, wherein It also includes square iron (2) and base plate (1). The two square irons (2) are fixedly installed on the bottom sides of the pad (3). The bottom of the square iron (2) is fixedly installed with the base plate (1). The bottom of the ejector plate (17) abuts against the top of the base plate (1).

4. The secondary ejection mechanism of an injection mold according to claim 1, wherein The secondary ejection assembly also includes a second mounting groove (20), a mounting block (21), and a limiting plate (8). The second mounting groove (20) is opened on one side of the B plate (6). The mounting block (21) is fixedly installed inside the second mounting groove (20). The limiting plate (8) is fixedly installed on one side of the mounting block (21). The inner sliding plate (22) is fixedly installed at the bottom of the limiting plate (8).

5. The secondary ejection mechanism of an injection mold according to claim 1 or 4, characterized in that, Two symmetrical compression springs (24) are provided between one end of the slider (23) and the inner wall of one side of the first mounting groove (15). The outer end of the slider (23) is arc-shaped, matching the contour of the trapezoidal groove (16) and the groove (25).

6. The secondary ejection mechanism of an injection mold according to claim 1, wherein It also includes guide posts (9) and guide sleeves (14). The guide posts (9) are fixedly installed at the bottom four corners of plate A (5), and the guide sleeves (14) are fixedly installed at the top four corners of plate B (6). The guide posts (9) are slidably connected to the inside of the guide sleeves (14).

7. The secondary ejection mechanism of an injection mold according to claim 1, wherein The trapezoidal groove (16) includes a vertical section and an inclined section, wherein the vertical section is used to guide the slider (23) and the inclined section is used to force the slider (23) to retract.

8. The secondary ejection mechanism of an injection mold according to claim 2, wherein The reset springs (18) are multiple and evenly arranged between the ejector plate (17) and the pad (3), and are used to automatically reset the ejector plate (17) after ejection.

9. The secondary ejection mechanism of an injection mold according to claim 1, wherein It also includes an upper positioning block (11) and a lower positioning block (10). The upper positioning block (11) is fixedly installed at the bottom four corners of plate A (5), and the lower positioning block (10) is fixedly installed at the top four corners of plate B (6). The lower positioning block (10) and the upper positioning block (11) are connected during mold closing to ensure accuracy.

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