A cushioning structure for an ejection device of an injection molding machine

Abstract

This utility model relates to the field of injection molding machine ejection, specifically to a buffer structure for an injection molding machine ejection device. The structure includes a plunger with a connecting post fixedly connected to its bottom, the connecting post having external threads on its outer wall; and a buffer assembly comprising a rubber block snapped onto the top of the plunger, a mating assembly between the rubber block and the plunger, a buffer frame fixedly connected to the top of the rubber block, a silicone pad fixedly connected to the top of the buffer frame, and a protrusion fixedly connected to the upper surface of the silicone pad. Through the design of the buffer assembly, the impact force of the ejector pin can be gradually dissipated from small to large, thereby stabilizing the ejection of the injection molded part while minimizing the risk of damage. This is especially beneficial for thin-walled, easily deformable injection molded parts, effectively reducing impact damage during ejection and ensuring high production yield.

Description

Technical Field

[0001] This utility model relates to the field of injection molding machine ejection, and specifically to a buffer structure for injection molding machine ejection device. Background Technology

[0002] Injection molds consist of two parts: a moving mold and a fixed mold. By closing the mold, a cavity matching the shape of the plastic part is formed. High-temperature molten plastic is injected into the cavity and, after cooling and solidification, the desired shape of the plastic part can be replicated. The ejection mechanism is a key component that removes the solidified plastic part from the cavity after the mold opens. It typically consists of ejector pins, ejector plates, and return pins. Its working principle is that after the mold opening action is completed, the power of the injection molding machine drives the ejector pins and other components forward, using mechanical force, hydraulic pressure, or pneumatic pressure to smoothly eject the plastic part from the cavity, ensuring intact demolding. Some ejector pins also have rubber parts added to their ends for cushioning to protect the plastic part.

[0003] For example, Chinese Patent Publication No. CN212312662U discloses an ejection device for injection molding machines. The three through slots A on the top plate of this device are arranged in a triangular structure, so that when the ejection sleeve and ejection rod inside the through slot A eject the plastic part, they eject the plastic part at three points on the edge of the plastic part. This ensures that the ejection sleeve connected by the spring and the ejection rod with a rubber contact buffer on the top are not affected by the structure of the plastic part when ejecting the plastic part, so that the plastic part is less likely to deviate and the ejection is more stable.

[0004] Currently, while adding a rubber buffer to the end of the ejector rod can alleviate the impact force during ejection, the buffering capacity of a single rubber component is limited by its material properties, and its deformation energy absorption range is fixed, making it difficult to cope with complex working conditions. Especially for thin-walled plastic parts, when the rubber components are in direct contact, the rigid fit of the contact surfaces often leads to localized stress concentration at the moment of ejection. Moreover, the planar contact form of the rubber components further exacerbates the pressure accumulation, causing the buffering effect to almost fail. This can easily cause irreversible deformation of thin parts due to uneven stress. Therefore, it is necessary to invent a buffer structure for the ejection device of an injection molding machine to solve the above problems. Utility Model Content

[0005] The purpose of this invention is to provide a buffer structure for the ejection device of an injection molding machine. A softer silicone pad makes initial contact with the injection molded part, providing initial buffering against the impact of the ejector pin. A honeycomb-shaped buffer frame further buffers the impact. A rubber block with a hardness slightly higher than the buffer frame and silicone pad provides stable support for the buffer frame and silicone pad, ensuring the effectiveness of the ejection action. The protrusion design effectively avoids concentrated stress caused by a large-area rigid collision during planar contact. This solves the problem of injection molded part deformation caused by uneven buffering, ensuring a high production yield.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a buffer structure for an ejector device of an injection molding machine, disposed at the end of the ejector rod of the ejector device, comprising:

[0007] A plunger, the bottom of which is fixedly connected to a connecting post, the outer wall of which is provided with external threads;

[0008] A buffer assembly includes a rubber block that is snapped onto the top of a plunger. A mating assembly is provided between the rubber block and the plunger. A buffer frame is fixedly connected to the top of the rubber block, and a silicone pad is fixedly connected to the top of the buffer frame. A protrusion is fixedly connected to the upper surface of the silicone pad.

[0009] Preferably, the docking assembly includes a positioning rod, which is fixedly connected to the top of the plunger, and a positioning ball is fixedly connected to the top of the positioning rod. The positioning ball, the positioning rod, and the plunger are coaxially arranged.

[0010] Preferably, the inner wall of the rubber block is provided with a spherical groove, the inner diameter of the spherical groove is equal to the outer diameter of the positioning ball, and the cross-section of the spherical groove is circular.

[0011] Preferably, the inner wall of the rubber block has an opening, the inner diameter of which is equal to the outer diameter of the positioning rod, and the opening, the spherical groove and the rubber block are coaxially arranged.

[0012] Preferably, both the upper and lower ends of the passage are open structures, and the opening at the top of the passage is connected to the interior of the spherical groove.

[0013] Preferably, the cross-section of the protrusion is semi-circular, and the protrusion is a hemispherical protrusion.

[0014] Preferably, at least three sets of buffer frames are provided, and the buffer frames are hexagonal frame structures.

[0015] The technical effects and advantages provided by this utility model in the above technical solution are as follows:

[0016] This invention, through the design of the buffer component, can gradually dissipate the impact force of the ejector rod from "small to large," thereby stabilizing the ejection of the injection molded part while minimizing the risk of damage to the molded part. Especially for thin-walled, easily deformable injection molded parts, it can effectively reduce the impact damage at the moment of ejection, ensuring the production yield of injection molded parts. Through the design of the docking component, the docking component can be quickly replaced when the buffer component reaches the end of its service life and its function declines, so that the ejection device can always have excellent buffering effect. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0018] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0019] Figure 2 This is a schematic diagram of the exploded structure of this utility model;

[0020] Figure 3 This is a schematic cross-sectional view of the present invention.

[0021] Figure 4 This is a cross-sectional structural diagram of the rubber block of this utility model.

[0022] Legend:

[0023] 1. Plunger; 2. Buffer assembly; 21. Rubber block; 22. Buffer frame; 23. Silicone pad; 24. Protrusion; 3. Connecting assembly; 31. Positioning rod; 32. Positioning ball; 33. Spherical groove; 34. Through port; 4. Connecting post; 5. External thread. Detailed Implementation

[0024] To enable those skilled in the art to better understand the technical solution of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings.

[0025] This utility model provides, for example Figure 1 - Figure 3 The buffer structure shown is for the ejection device of an injection molding machine and is disposed at the end of the ejector rod of the ejection device, including a plunger 1 and a buffer assembly 2.

[0026] A connecting post 4 is fixedly connected to the bottom of the plunger 1, and the outer wall of the connecting post 4 is provided with an external thread 5;

[0027] The buffer assembly 2 includes a rubber block 21, which is snapped onto the top of the plunger 1. The rubber block 21, with a hardness slightly higher than that of the buffer frame 22 and the silicone pad 23, provides stable support for them. A connecting assembly 3 is provided between the rubber block 21 and the plunger 1. The top of the rubber block 21 is fixedly connected to the buffer frame 22. The hardness of the rubber block 21 is greater than that of the buffer frame 22. The buffer frame 22 is made of rubber, and at least three sets of buffer frames 22 are provided. These multiple sets of buffer frames 22 together form a honeycomb structure. The honeycomb arrangement of the buffer frames 22 allows each frame to deform uniformly to absorb impact force. The design provides secondary buffering against the impact force of the ejector pin. The buffer frame 22 is a hexagonal frame structure, with a silicone pad 23 fixedly connected to its top. The buffer frame 22 is harder than the silicone pad 23. During the ejection process, the softer silicone pad 23 initially buffers the impact force of the ejector pin. A protrusion 24 is fixedly connected to the upper surface of the silicone pad 23. The protrusion 24 has a semi-circular cross-section and is a hemispherical protrusion. In the initial ejection stage, the protrusion 24 only contacts the injection molded part with its tip. As the ejection force increases, the protrusion 24 is gradually compressed and deformed, and the contact area gradually expands from small to large. This point-to-surface transition contact method effectively avoids the concentrated stress generated by the instantaneous large-area rigid collision during planar contact. Especially for thin-walled, easily deformable injection molded parts, it can effectively reduce impact damage at the moment of ejection.

[0028] like Figure 2 - Figure 3 As shown, the docking assembly 3 includes a positioning rod 31, which is fixedly connected to the top of the plunger 1. A positioning ball 32 is fixedly connected to the top of the positioning rod 31. The positioning ball 32, the positioning rod 31 and the plunger 1 are coaxially arranged. The rubber block 21 and the plunger 1 can be fixed together by using the positioning rod 31 in conjunction with the positioning ball 32 and the spherical groove 33.

[0029] like Figure 4 As shown, a spherical groove 33 is provided on the inner wall of the rubber block 21. The inner diameter of the spherical groove 33 is equal to the outer diameter of the positioning ball 32. The positioning ball 32 can be limited by the spherical groove 33. The cross-section of the spherical groove 33 is circular. An opening 34 is provided on the inner wall of the rubber block 21. The inner diameter of the opening 34 is equal to the outer diameter of the positioning rod 31. The positioning rod 31 can be limited by the opening 34. The opening 34, the spherical groove 33 and the rubber block 21 are coaxially arranged. Both the upper and lower ends of the opening 34 are open structures. The opening at the top of the opening 34 is connected to the inside of the spherical groove 33. The positioning ball 32 can be easily removed from the inside of the spherical groove 33 by using the opening 34.

[0030] The working principle of this utility model is as follows: First, an internal thread hole matching the external thread 5 is opened on the inner wall of the ejector rod end of the ejector device of the injection molding machine. Then, the connecting column 4 is threaded through the internal thread hole connected to the external thread 5, so that the plunger 1 can be fixed to the rod end of the ejector rod.

[0031] When the ejector rod drives the plunger 1 to eject the injection molded part, the silicone pad 23 will be the first to contact the injection molded part. Since the hardness of the silicone pad 23 is much lower than that of the rubber block 21, the softer silicone pad 23 can initially buffer the impact force of the ejector rod during the process of the rubber block 21 pushing the silicone pad 23 out. At the same time, the silicone pad 23 will deform sufficiently due to the force, significantly increasing the contact area with the injection molded part, ensuring that the ejection force is evenly applied to the surface of the plastic part.

[0032] When the silicone pad 23 deforms under force, it simultaneously compresses the buffer frame 22, causing it to deform as well. The multiple hexagonal buffer frames 22 between the rubber block 21 and the silicone pad 23 form a honeycomb structure. This design can provide secondary buffering against the impact force of the push rod, and the honeycomb structure can evenly absorb the impact force through the deformation of each buffer frame 22, further optimizing the distribution of the push force.

[0033] A rubber block 21, with a hardness slightly higher than that of the buffer frame 22 and the silicone pad 23, provides stable support for the buffer frame 22 and the silicone pad 23, ensuring the effectiveness of the ejection action and avoiding insufficient ejection force due to excessive buffering. It is worth noting that the multiple hemispherical protrusions 24 on the contact surface between the silicone pad 23 and the injection molded part gradually expand the contact range as the ejection force increases. Combined with the initial buffering of the silicone pad 23, the secondary energy absorption of the buffer frame 22, and the rigid support of the rubber block 21, the impact force of the ejector rod is gradually dissipated from small to large, thereby stabilizing the ejection of the injection molded part while minimizing the risk of damage to the plastic part.

[0034] When the silicone pad 23 or the buffer frame 22 is damaged and needs to be replaced, simply pull the rubber block 21 forcefully. Due to the excellent deformation ability of the rubber block 21, the positioning ball 32 will move out of the spherical groove 33 through the through-hole 34, thus separating the rubber block 21 from the plunger 1. Then, align the through-hole 34 at the bottom of the replaced rubber block 21 with the positioning ball 32 and press the rubber block 21 forcefully, so that the positioning ball 32 can be inserted into the spherical groove 33 through the through-hole 34. At this time, the positioning rod 31, together with the positioning ball 32 and the spherical groove 33, can fix the rubber block 21 and the plunger 1 together, thereby completing the replacement of the rubber block 21.

[0035] The foregoing description only illustrates certain exemplary embodiments of the present invention. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A buffer structure for an ejector device of an injection molding machine, disposed at the end of the ejector rod of the ejector device, characterized in that, include: A plunger (1) is fixedly connected to a connecting post (4) at its bottom, and the outer wall of the connecting post (4) is provided with an external thread (5). The buffer assembly (2) includes a rubber block (21), which is snapped onto the top of the plunger (1). A docking assembly (3) is provided between the rubber block (21) and the plunger (1). A buffer frame (22) is fixedly connected to the top of the rubber block (21), and a silicone pad (23) is fixedly connected to the top of the buffer frame (22). A protrusion (24) is fixedly connected to the upper surface of the silicone pad (23).

2. The buffer structure for the ejection device of an injection molding machine according to claim 1, characterized in that: The docking assembly (3) includes a positioning rod (31), which is fixedly connected to the top of the plunger (1). A positioning ball (32) is fixedly connected to the top of the positioning rod (31). The positioning ball (32), the positioning rod (31), and the plunger (1) are coaxially arranged.

3. The buffer structure for the ejection device of an injection molding machine according to claim 1, characterized in that: The inner wall of the rubber block (21) is provided with a spherical groove (33), the inner diameter of the spherical groove (33) is equal to the outer diameter of the positioning ball (32), and the cross-section of the spherical groove (33) is circular.

4. A buffer structure for an ejector device of an injection molding machine according to claim 3, characterized in that: The inner wall of the rubber block (21) is provided with an opening (34), the inner diameter of the opening (34) is equal to the outer diameter of the positioning rod (31), and the opening (34), the spherical groove (33) and the rubber block (21) are coaxially arranged.

5. A buffer structure for an ejector device of an injection molding machine according to claim 4, characterized in that: Both ends of the opening (34) are open structures, and the opening at the top of the opening (34) is connected to the interior of the spherical groove (33).

6. A buffer structure for an ejector device of an injection molding machine according to claim 1, characterized in that: The cross-section of the protrusion (24) is semi-circular, and the protrusion (24) is a hemispherical protrusion.

7. A buffer structure for an ejector device of an injection molding machine according to claim 1, characterized in that: The buffer frame (22) is provided in at least three sets, and the buffer frame (22) is a hexagonal frame structure.

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