A spiral ejection structure for injection molds

Abstract

This utility model discloses a spiral ejection structure for injection molds, including a fixed mold base and a movable mold base that closes with the fixed mold base. The fixed mold base has three sliding grooves, and sliders are slidably connected to the three sliding grooves. The three sliders are evenly distributed circumferentially and fit around the molding cavity. A rotating cylinder is rotatably connected to the fixed mold base. One end of the rotating cylinder is located in the cavity and has a threaded part at that end. The cavity, rotating cylinder, and threaded part cooperate for product molding. A fixed plate is installed on the outside of the fixed mold base, and a driving device for driving the rotating cylinder to rotate is installed on the fixed plate. A pin hole is provided in the center of the rotating cylinder. A top plate is movably connected to the bottom of the fixed mold base, and an ejector pin for extending into the pin hole is installed on the top plate. Through the coordinated cooperation of the driving device, rotating cylinder, top plate, and ejector pin, this utility model realizes the automatic unscrewing and ejection of internally threaded products, eliminating the need for manual intervention to disassemble products with internal threads, thus improving production efficiency and automation level.

Description

Technical Field

[0001] This utility model relates to the field of injection mold technology, specifically a spiral ejection structure for injection molds. Background Technology

[0002] Injection molds are precision tools used for molding plastic products. They inject molten plastic into a closed mold cavity under high pressure, and after cooling and solidification, the mold is opened to obtain the plastic product of the desired shape. Injection molds typically consist of two parts: a moving mold and a fixed mold. They include key structures such as a gating system, a cooling system, an ejection system, and a guiding mechanism. They are widely used in mass production fields such as automobiles, electronics, home appliances, and daily necessities. Their design and manufacturing quality directly affect the precision, surface quality, and production efficiency of the product.

[0003] The internal thread structure of plastic parts presents problems such as molding difficulties, demolding difficulties, and complex structure during injection molding. Currently, the production of internal thread plastic parts mostly adopts manual demolding, that is, the product is removed from the mold by manually rotating it. However, this demolding method is inefficient, especially when mass production is required to meet the production capacity. Utility Model Content

[0004] The purpose of this invention is to provide a spiral ejection structure for injection molds to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A spiral ejection structure for an injection mold includes a fixed mold base and a movable mold base that closes with the fixed mold base. The fixed mold base has three sliding grooves, and sliders are slidably connected to the three sliding grooves respectively. The three sliders are evenly distributed circumferentially and fit around the molding cavity. A rotating cylinder is rotatably connected to the fixed mold base. One end of the rotating cylinder is located in the mold cavity and has a threaded portion at that end. The mold cavity, rotating cylinder, and threaded portion cooperate for product molding. A fixing plate is installed on the outside of the fixed mold base, and a driving device for driving the rotating cylinder to rotate is installed on the fixing plate. A pin hole is provided at the center of the rotating cylinder. A top plate is movably connected to the bottom of the fixed mold base, and an ejector pin for extending into the pin hole is installed on the top plate.

[0007] Furthermore, the driving device includes a motor, the output end of which is provided with a driving wheel, and the end of the rotating cylinder away from the threaded part is equipped with a driven wheel. The driving wheel is connected to the driven wheel via a transmission belt.

[0008] Furthermore, each of the three sliders has a slot at one end away from each other. The slot is located on one side of the cavity and has a guide slope. The moving mold base has three inserts, the positions of which correspond one-to-one with the three slots. Each insert has a guide slope two on one side of the corresponding guide slope one, and the guide slope two cooperates with the guide slope one.

[0009] Furthermore, an exhaust groove is provided at one end of the surface of the ejector pin near the top, and several escape grooves are provided at equal intervals along the circumference of the surface of the ejector pin. All of the escape grooves are located below the exhaust groove and are connected to the exhaust groove.

[0010] Furthermore, the exhaust groove is an annular groove, the escape groove is an elongated groove, and the exhaust groove and the several escape grooves have the same depth.

[0011] Furthermore, the top of the ejector pin has an inverted conical structure.

[0012] The beneficial effects of this utility model are:

[0013] After injection molding, the moving mold base separates from the fixed mold base, leaving the molded product on the fixed mold base. Then, the operator manually or with tools pushes the three sliders outwards to release the product from its grip. Next, the drive device is activated, rotating the rotating cylinder. The rotating cylinder drives the threaded portion on its outer periphery to rotate synchronously. Simultaneously, the external ejection device activates, pushing the top plate slowly towards the product, moving the ejector pin accordingly. During this movement, the ejector pin continuously and gently presses against the solidified material portion of the product within the pin hole, providing stable axial support. This creates a relative unscrewing motion between the threaded portion and the product's internal thread, achieving thread disengagement. Once the product's internal thread has completely exited the threaded portion, the top plate continues to move, and the ejector pin completely ejects the disengaged product from the fixed mold base, completing the entire demolding process. Through the coordinated operation of the drive device, rotating cylinder, top plate, and ejector pin, automatic unscrewing and ejection of internally threaded products is achieved, eliminating the need for manual intervention in disassembling products with internal threads, thus improving production efficiency and automation levels.

[0014] Other features and advantages of this invention will be described in detail in the following detailed description section. Attached Figure Description

[0015] Figure 1 : Overall structural diagram of this utility model.

[0016] Figure 2 The explosion of the moving mold base and the fixed mold base of this utility model Figure 1 .

[0017] Figure 3 The explosion of the moving mold base and the fixed mold base of this utility model Figure 2 .

[0018] Figure 4 : Overall structural cross-sectional view of this utility model.

[0019] Figure 5 : Figure 4 Enlarged view of the structure of part A.

[0020] Figure 6 : A cross-sectional view of the connection between the slider and the insert block of this utility model.

[0021] Figure 7 : A structural diagram of the ejector pin of this utility model.

[0022] Reference numerals in the attached drawings: 1. Fixed mold base; 2. Moving mold base; 3. Fixed plate; 4. Drive device; 5. Top plate; 11. Slide groove; 12. Slider; 13. Cavity; 14. Rotating cylinder; 15. Threaded part; 21. Insert block; 22. Guide slope two; 41. Motor; 42. Drive wheel; 43. Driven wheel; 44. Transmission belt; 51. Ejector pin; 52. Venting groove; 53. Exhaust groove; 54. Inverted cone structure; 121. Slot; 122. Guide slope one; 141. Pin hole. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0024] Please refer to Figure 1-7 ;

[0025] A spiral ejection structure for an injection mold includes a fixed mold base 1 and a movable mold base 2 that closes with the fixed mold base 1. The fixed mold base 1 has three grooves 11 evenly distributed along the circumference. Each groove 11 has a slider 12 slidably connected to it. The three sliders 12 fit together to form a cavity 13 for molding the outer contour of the product. A rotating cylinder 14 is rotatably connected to the fixed mold base 1. One end of the rotating cylinder 14 is located in the cavity 13, and a threaded portion 15 is provided on the outer periphery of that end. The cavity 13, the rotating cylinder 14, and the threaded portion 15 work together to mold an injection molded product with internal threads and a conical cross-section. The movable mold base 2 has a conventional gating mechanism for injecting molten plastic into the cavity 13. The gating mechanism is a common structure in existing injection molds and will not be described in detail here. After mold closing, the injection molding machine injects high-temperature molten plastic into the cavity 13 formed by the three sliders 12 through the gating mechanism. After cooling and solidification, a conical product with internal threads is formed. Because the product's diameter gradually increases from the outside to the inside, it cannot be directly removed from the mold via axial demolding. Before demolding, the three sliders 12 must be released from their grip on the product's outer wall. Additionally, the product has internal threads. Therefore, a fixing plate 3 is installed on the outside of the fixed mold base 1. A drive device 4 for rotating the rotating cylinder 14 is mounted on the fixing plate 3. When the drive device 4 is activated, it rotates the rotating cylinder 14, causing the threaded portion 15 within the cavity 13 to rotate synchronously. A pinhole 141 is located at the center of the rotating cylinder 14. A top plate 5 is movably connected to the bottom of the fixed mold base 1. Ejector pins 51 for extending into the pinhole 141 are mounted on the top plate 5. During demolding, the external ejection device pushes the top plate 5 towards the product, thereby moving the ejector pins 51 forward to assist in the product's ejection.

[0026] Working principle: After injection molding, the moving mold base 2 first separates from the fixed mold base 1. At this time, the injection-molded product remains on the fixed mold base 1. Then, the operator manually or with the help of tools pushes the three sliders 12 outward to release the product from the tightness. Next, the drive device 4 is started to drive the rotating cylinder 14 to rotate. The rotating cylinder 14 drives the threaded part 15 on its outer periphery to rotate synchronously. At the same time, the external ejection device starts to operate, pushing the top plate 5 to move slowly towards the product, driving the ejector pin 51 to move accordingly. During the movement, the ejector pin 51 continuously and lightly presses against the solidified part of the product in the pin hole 141, providing stable axial support force, so that the threaded part 15 and the internal thread of the product generate a relative unscrewing motion, realizing thread unpinning. When the internal thread of the product is completely out of the threaded part 15, the top plate 5 continues to move, and the ejector pin 51 completely pushes the product that has been de-threaded out of the fixed mold base 1, completing the entire demolding process. Through the coordinated operation of the drive device 4, rotating cylinder 14, top plate 5 and ejector pin 51, the automatic unscrewing and ejection of internally threaded products is realized, eliminating the need for manual intervention to disassemble products with internal threads, thereby improving production efficiency and automation level.

[0027] In this embodiment, the drive device 4 includes a motor 41, with a drive wheel 42 at the output end of the motor 41. A driven wheel 43 is installed at the end of the rotating cylinder 14 away from the threaded portion 15. The drive wheel 42 is connected to the driven wheel 43 via a transmission belt 44. The driven wheel 43 is fixedly mounted to the rotating cylinder 14 to ensure that it can synchronously drive the rotating cylinder 14 to rotate when it rotates. When the motor 41 starts, the drive wheel 42 rotates accordingly, transmitting power to the driven wheel 43 via the transmission belt 44, thereby driving the rotating cylinder 14 to rotate and realizing the rotation of the threaded portion 15.

[0028] Before mold closing, since the three sliders 12 are initially in a separated state, to avoid the inconvenience of manually pushing the sliders 12 to close them, slots 121 are provided at the ends of the three sliders 12 that are far apart from each other. Each slot 121 has a guide slope 122 on one side of the cavity 13. Three inserts 21 are provided on the moving mold base 2, with their positions corresponding one-to-one with the three slots 121. Each insert 21 has a guide slope 22 on one side of its corresponding guide slope 122, which cooperates with the guide slope 122. Specifically, the slots 121 adopt a parallelogram design, while the end of the insert 21 that inserts into the slot 121 has a right-angled trapezoidal design. The width of the insert end of the insert 21 is smaller than the width of the slot 121, facilitating initial insertion. During the mold closing process, when the moving mold base 2 moves closer to the fixed mold base 1, the three insert blocks 21 first insert into the corresponding slots 121. The guide slope 22 on the insert block 21 fits with the guide slope 122 on the slider 12. As the moving mold base 2 moves, the insert blocks 21 push the three sliders 12 to move towards the center, eventually achieving automatic closing and tight fitting to form a complete cavity 13. This realizes the automatic enclosure of the sliders 12 without manual intervention, saving labor and improving work efficiency.

[0029] In this embodiment, an venting groove 52 is provided at one end of the ejector pin 51 near the top. A plurality of escape grooves 53 are equally spaced along the circumference of the ejector pin 51, all located below and connected to the venting groove 52. During injection molding, as molten plastic is injected into the cavity 13 under high pressure, the air inside the cavity 13 is compressed and flows into the venting groove 52 through the tiny gap between the ejector pin 51 and the pin hole 141. After entering the venting groove 52, the air is then discharged to the outside of the mold through the multiple escape grooves 53, preventing the air inside the cavity 13 from being compressed and immediately reaching high temperatures, which could cause localized carbonization, scorching, and bubbles in the parts of the product in contact with the high-temperature air. Furthermore, the venting groove 52 is an annular groove, and the escape grooves 53 are elongated grooves. The depth of the venting groove 52 and the multiple escape grooves 53 are consistent. The annular structure of the venting groove 52 can collect gas from the entire circumference of the ejector pin 51, improving the efficiency and uniformity of venting.

[0030] In this embodiment, the top of the ejector pin 51 is an inverted cone structure 54. The inverted cone structure 54 can temporarily hold the product on the ejector pin 51 after it is ejected, preventing the product from falling directly due to its own weight or the impact force of ejection, and avoiding defects such as surface scratches, deformation or breakage caused by the product falling and colliding. Preferably, the angle of the inverted cone is between 1-5°, which can provide sufficient holding force to ensure that the product stays stably, without causing demolding difficulties or damage to the inner wall of the product due to an excessively large angle.

[0031] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0032] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other implementations that can be understood by those skilled in the art.

Claims

1. A spiral ejection structure for an injection mold, comprising a fixed mold base (1) and a movable mold base (2) that closes with the fixed mold base (1), characterized in that, The fixed mold base (1) is provided with three sliding grooves (11), and sliders (12) are slidably connected to the three sliding grooves (11). The three sliders (12) are evenly distributed in a circle and fit around the forming cavity (13). A rotating cylinder (14) is rotatably connected to the fixed mold base (1). One end of the rotating cylinder (14) is located in the cavity (13) and a threaded part (15) is provided at that end. The cavity (13), the rotating cylinder (14) and the threaded part (15) are used for product molding. A fixing plate (3) is installed on the outside of the fixed mold base (1). A driving device (4) for driving the rotating cylinder (14) to rotate is installed on the fixing plate (3). A pin hole (141) is provided in the center of the rotating cylinder (14). A top plate (5) is movably connected to the bottom of the fixed mold base (1). A ejector pin (51) for inserting into the pin hole (141) is installed on the top plate (5).

2. The spiral ejection structure of an injection mold according to claim 1, characterized in that, The drive device (4) includes a motor (41), the output end of which is provided with a drive wheel (42), and a driven wheel (43) is installed at the end of the rotating cylinder (14) away from the threaded part (15). The drive wheel (42) is connected to the driven wheel (43) via a transmission belt (44).

3. The spiral ejection structure of an injection mold according to claim 1, characterized in that, Each of the three sliders (12) has a slot (121) at one end away from each other. The slot (121) is located on one side of the cavity (13) and has a guide slope (122). The moving mold base (2) is provided with three inserts (21). The positions of the three inserts (21) correspond one-to-one with the three slots (121). Each insert (21) has a guide slope (22) on one side of the corresponding guide slope (122). The guide slope (22) cooperates with the guide slope (122).

4. The spiral ejection structure of an injection mold according to claim 1, characterized in that, The ejector pin (51) has an exhaust groove (52) at one end near the top. The ejector pin (51) has several escape grooves (53) at equal intervals along the circumferential direction. The several escape grooves (53) are all located below the exhaust groove (52) and are connected to the exhaust groove (52).

5. The spiral ejection structure of an injection mold according to claim 4, characterized in that, The exhaust groove (52) is an annular groove, and the escape groove (53) is a long strip groove. The exhaust groove (52) and the several escape grooves (53) have the same depth.

6. The spiral ejection structure of an injection mold according to claim 1, characterized in that, The top of the ejector pin (51) has an inverted cone structure (54).

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