A resilient inclined ejector mechanism for injection moulds

Abstract

The utility model relates to injection mold technical field, concretely is a kind of elastic inclined ejector mechanism for injection mold, including front mould plate, rear mould plate, front mould core, rear mould core, upper pin plate, lower pin plate, elastic pin, square iron and fixed plate, its core lies in, the head of elastic pin is equipped with the reverse buckle structure for the reverse buckle of shaped product, middle part is equipped with neck section, upper end to neck section gradually narrow and form the inclined section of guiding elastic pin resilience, the upper portion of pin hole is equipped with the inclined guide hole with the shape matching of inclined section, when clamping, inclined section is constrained in inclined guide hole to make elastic pin keep straight state, when ejecting, upper pin plate and lower pin plate drive elastic pin upward movement, when inclined section is released from the constraint of inclined guide hole, elastic pin can produce elastic resilience along neck section, to realize the separation with product reverse buckle.This mechanism structure is compact, action is reliable, effectively solved the problem of reverse buckle demoulding in narrow space, simplified mould structure.

Description

Technical Field

[0001] This utility model relates to the field of injection mold technology, specifically to an elastic inclined ejector mechanism for injection molds. Background Technology

[0002] In injection molding, products with internal or lateral undercut structures are very common. These products require special demolding mechanisms, such as sliders or angled ejectors, to allow for or actively release the undercut structure during demolding; otherwise, the product will be stuck and unable to eject. Traditional angled ejector mechanisms achieve demolding through angled movement, but they require a certain amount of installation space and angle, making them difficult to implement in extremely confined mold spaces, deep undercut locations, or complex surrounding structures. Even if installation is possible, the structure is often very complex, resulting in high manufacturing costs and unreliable performance. Therefore, for precision plastic parts with compact internal spaces and small undercut features, existing technologies have significant limitations, necessitating a simplified, space-saving, stable, and reliable undercut demolding mechanism suitable for confined spaces. Utility Model Content

[0003] The purpose of this invention is to provide an elastic inclined ejector mechanism for injection molds to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, this utility model provides the following technical solution: an elastic inclined ejector demolding mechanism for injection molds, comprising a front mold plate, a rear mold plate, a front mold core, a rear mold core, an upper ejector plate, a lower ejector plate, elastic ejector pins, a square iron, and a fixing plate; the front mold plate is connected to the rear mold plate, the front mold core is fixed to the front mold plate, the rear mold core is fixed to the rear mold plate, the square iron is disposed between the rear mold plate and the fixing plate, the upper ejector plate is connected to the lower ejector plate and is located between the rear mold plate and the fixing plate; the front mold core, the rear mold core, and the elastic ejector pins, after mold closing, together form the cavity of the product; the rear mold core is provided with ejector pin holes, and the lower end of the elastic ejector pin is fixed to the lower ejector plate, the elastic... The upper end of the ejector pin passes through the ejector pin hole on the rear mold core and extends into the product cavity; the head of the elastic ejector pin is provided with an undercut structure for forming the undercut of the product, and the middle part of the elastic ejector pin is provided with a narrow neck section. The upper end of the elastic ejector pin gradually narrows to the narrow neck section to form an inclined section that guides the elastic ejector pin to rebound; the upper part of the ejector pin hole is provided with an inclined guide hole that matches the shape of the inclined section. When the mold is closed, the inclined section is constrained in the inclined guide hole, so that the elastic ejector pin remains straight; when ejecting, the upper ejector plate and the lower ejector plate drive the elastic ejector pin to move upward. When the inclined section is freed from the constraint of the inclined guide hole, the elastic ejector pin can generate elastic rebound along the narrow neck section to achieve separation from the undercut of the product.

[0005] Preferably, the inclined guide hole has a straight wall on one side corresponding to the inverted structure and an inclined wall on the side opposite to the inverted structure, so as to allow the elastic pin to rebound to the inclined wall side after being released from the constraint.

[0006] Preferably, the inclination angle of the sidewall of the inclined section is the same as the inclination angle of the inner wall of the inclined guide hole, and the inclination angle is 3-7 degrees.

[0007] Preferably, after the elastic ejector pin moves upward by 25-40mm during the ejection process, its inclined section completely disengages from the inclined guide hole and rebounds.

[0008] Preferably, the elastic pin has a rebound angle of 5-6 degrees when it rebounds.

[0009] Preferably, the elastic pin is made of spring steel or titanium alloy.

[0010] Preferably, the maximum width of the elastic pin is 10.95-11.15 mm.

[0011] Compared with existing technologies, this utility model provides an elastic inclined ejector demolding mechanism for injection molds, which has the following beneficial effects: This utility model, by setting ejector pin holes with specific inclined guide holes in the rear mold core, and cooperating with the design of elastic ejector pins with undercut structures, narrow neck sections, and inclined sections, allows the mold core to press the elastic ejector pins upright and constrain them to maintain an upright state during mold closing, ensuring accurate forming of the undercut on the product. During ejection, the elastic ejector pin moves upward with the ejector plate assembly. Once its inclined section is freed from the constraint of the guide hole, it can utilize the elasticity of its own material and the flexible design of the narrow neck section to quickly spring back to one side at a predetermined angle, thereby achieving separation from the undercut on the product. This mechanism cleverly combines ejection action with elastic deformation, eliminating the need for complex drive mechanisms, greatly simplifying the mold structure, and reducing manufacturing costs. Its operation is smooth and reliable, effectively avoiding product damage during ejection, significantly improving demolding success rate and product quality. It is particularly suitable for compact space scenarios where traditional sliders or inclined ejectors are difficult to arrange, and has high practical value and promising prospects for promotion. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of the present invention before injection molding in the mold-closed state; Figure 2 This is a schematic diagram of the injection-molded structure in the mold-closed state of this utility model; Figure 3 This is a schematic diagram of the elastic ejector pin rebound structure of this utility model; Figure 4 for Figure 3 Enlarged view of point A in the middle; Figure 5 This is a schematic diagram of the demolding state of this utility model.

[0013] Explanation of reference numerals in the attached drawings: 1. Front mold plate; 2. Rear mold plate; 3. Front mold core; 4. Rear mold core; 41. Ejector pin hole; 411. Inclined guide hole; 5. Upper ejector plate; 6. Lower ejector plate; 7. Elastic ejector pin; 71. Undercut structure; 72. Neck section; 73. Inclined section; 8. Square iron; 9. Fixing plate; 10. Product; 11. Cavity. Detailed Implementation

[0014] The technical solutions of the present utility model will now be described with reference to the accompanying drawings in the embodiments of the present utility model: like Figure 1-5 As shown, the present invention provides an elastic inclined ejector mechanism for injection molds, including a front mold plate 1, a rear mold plate 2, a front mold core 3, a rear mold core 4, an upper ejector plate 5, a lower ejector plate 6, an elastic ejector pin 7, a square iron 8, and a fixing plate 9.

[0015] The front mold plate 1 and the rear mold plate 2 are connected to form the basic frame of the mold, enabling the mold to open and close. The front mold core 3 is fixed to the front mold plate 1 and is used to shape the front end of the product 10. The rear mold core 4 is fixed to the rear mold plate 2 and, together with the front mold core 3, closes to form the complete cavity 11 of the product 10. The square iron plate 8 is placed between the rear mold plate 2 and the fixed plate 9. Its function is to support the rear mold plate 2 and create sufficient space between the rear mold plate 2 and the fixed plate 9 to accommodate the ejector plate and its movement. The fixed plate 9 is used to mount and fix the entire mold mechanism to the injection molding machine.

[0016] The upper ejector plate 5 and the lower ejector plate 6 are fixedly connected by bolts to form a whole, constituting the ejector plate assembly. This assembly is located in the space between the rear mold plate 2 and the fixed plate 9, and is driven by the ejector pin of the injection molding machine, allowing it to reciprocate along the mold opening and closing direction. After the front mold core 3, the rear mold core 4, and the elastic ejector pin 7 are closed, they together form the cavity 11 of the product 10. The rear mold core 4 is provided with an ejector pin hole 41, which is the channel for the movement of the elastic ejector pin 7.

[0017] The elastic ejector pin 7 is the core component of this mechanism. It is made of materials with high elastic limit and fatigue strength, such as spring steel or titanium alloy. The maximum width of the elastic ejector pin 7 is L1, which is 10.95-11.15 mm (preferably 11.05 mm) to ensure sufficient strength and elasticity. The lower end of the elastic ejector pin 7 is fixed to the lower ejector plate 6 by bolts, and the upper end passes through the ejector hole 41 on the rear mold core 4 and extends into the cavity 11 of the product 10. The head of the elastic ejector pin 7 has an undercut structure 71 for directly molding the undercut feature on the product 10. The middle part of the elastic ejector pin 7 has a narrow neck section 72. This section has a small cross-sectional dimension and is the weakest link in the entire elastic ejector pin 7, but it has good elastic deformation capacity, which is the key to the elastic bending of the elastic ejector pin 7. The upper end of the elastic ejector pin 7 gradually narrows to the narrow neck section 72 to form an inclined section 73 that guides the elastic ejector pin 7 to rebound. The lower part of the elastic ejector pin 7 is a vertical fixing section, which is mainly used for fixing with the lower ejector plate 6.

[0018] The upper part of the ejector pin hole 41 is provided with an inclined guide hole 411 that matches the shape of the inclined section 73. The inclined guide hole 411 is not a symmetrical structure. The inclined guide hole 411 has a straight wall on one side corresponding to the undercut structure 71 and an inclined wall on the opposite side to the undercut structure 71, so as to allow the elastic ejector pin 7 to rebound towards the inclined wall side after being freed from the constraint. The inclination angle of the side wall of the inclined section 73 is the same as the inclination angle of the inner wall of the inclined guide hole 411, and the inclination angle is 3-7 degrees (preferably 5 degrees). When the mold is closed, the inclined section 73 is constrained in the inclined guide hole 411, so that the elastic ejector pin 7 remains in a straight state; when ejecting, the upper ejector plate 5 and the lower ejector plate 6 drive the elastic ejector pin 7 to move upward. When the inclined section 73 is freed from the constraint of the inclined guide hole 411, the elastic ejector pin 7 can elastically rebound along the narrow neck section 72 to achieve separation from the undercut of the product 10. The maximum upward stroke of the elastic ejector pin 7 during ejection is L2, which is 25-40mm (preferably 33mm). Its inclined section 73 completely disengages from the inclined guide hole 411 and springs back. The springback angle of the elastic ejector pin 7 during springback is 5-6 degrees.

[0019] Working principle: Mold closing and injection molding stage: During mold closing, the front mold core 3 and the rear mold core 4 are closed. At this time, the inclined section 73 of the elastic ejector pin 7 is completely constrained within the inclined guide hole 411 of the rear mold core 4, forcing the elastic ejector pin 7 to remain upright. Subsequently, injection molding is performed, and the melt fills the cavity 11 formed by the front mold core 3, the rear mold core 4, and the undercut structure 71 of the head of the elastic ejector pin 7. The product 10 and its undercut are integrally molded.

[0020] Initial stage of mold opening and ejection: After injection molding, the mold first opens, with the front mold plate 1 causing the front mold core 3 to separate from the product 10. Next, the ejector pins of the injection molding machine push the upper ejector plate 5 and the lower ejector plate 6 upwards, causing the elastic ejector pins 7 fixed thereon to be ejected upwards together. In the initial ejection stage, the inclined section 73 of the elastic ejector pin 7 is still constrained by the inclined guide hole 411, and the elastic ejector pin 7 remains upright, smoothly ejecting the product 10 away from the rear mold core 4.

[0021] Elastic rebound and undercut disengagement stage: As the ejector plate assembly continues to move upward, causing the inclined section 73 of the elastic ejector pin 7 to rise completely and disengage from the constraint of the inclined guide hole 411 (when the ejection stroke reaches 25-40mm, preferably 33mm), the inclined section 73 of the elastic ejector pin 7 completely disengages from the constraint of the inclined guide hole 411. At this time, the elastic ejector pin 7, with its narrow neck section 72 as the elastic bending fulcrum, relies on the elasticity of its own material to undergo a slight bending rebound (the rebound angle is about 5-6 degrees) towards the inclined wall side of the inclined guide hole 411 (i.e., the side away from the undercut of the product). This rebound action causes the undercut structure 71 at the head of the elastic ejector pin 7 and the undercut feature of the product 10 to generate a relative displacement in the side, thereby successfully disengaging and completing demolding.

[0022] Reset phase: After demolding is completed, the injection molding machine ejector pin retracts, driving the ejector plate assembly and elastic ejector pin 7 to reset downwards until they return to their initial positions, preparing for the next injection cycle.

[0023] The above embodiments are merely some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.

Claims

1. An elastic inclined ejector mechanism for injection molds, comprising a front mold plate (1), a rear mold plate (2), a front mold core (3), a rear mold core (4), an upper ejector plate (5), a lower ejector plate (6), elastic ejector pins (7), a square iron plate (8), and a fixing plate (9); wherein the front mold plate (1) is connected to the rear mold plate (2), the front mold core (3) is fixed on the front mold plate (1), the rear mold core (4) is fixed on the rear mold plate (2), the square iron plate (8) is disposed between the rear mold plate (2) and the fixing plate (9), and the upper ejector plate (5) is connected to the lower ejector plate (6) and located between the rear mold plate (2) and the fixing plate (9); characterized in that: The front mold core (3), rear mold core (4), and elastic ejector pin (7) together form the cavity (11) of the product (10) after mold closing; the rear mold core (4) is provided with an ejector pin hole (41), the lower end of the elastic ejector pin (7) is fixed on the lower ejector plate (6), and the upper end of the elastic ejector pin (7) passes through the ejector pin hole (41) provided on the rear mold core (4) and extends into the cavity (11) of the product (10); the head of the elastic ejector pin (7) is provided with a tool for molding the product ( 10) The undercut structure (71) has a narrow neck section (72) in the middle of the elastic ejector pin (7). The upper end of the elastic ejector pin (7) gradually narrows to the narrow neck section (72) to form an inclined section (73) that guides the elastic ejector pin (7) to rebound. The upper part of the ejector pin hole (41) is provided with an inclined guide hole (411) that matches the shape of the inclined section (73). When the mold is closed, the inclined section (73) is constrained in the inclined guide hole (411) so that the elastic ejector pin (7) is held in place. In the straightened state; during ejection, the upper ejector plate (5) and the lower ejector plate (6) drive the elastic ejector pin (7) to move upward. When the inclined section (73) is freed from the constraint of the inclined guide hole (411), the elastic ejector pin (7) can generate elastic rebound along the narrow neck section (72) to achieve separation from the product (10) undercut; the inclined guide hole (411) has a straight wall on one side corresponding to the undercut structure (71) and an inclined wall on the side opposite to the undercut structure (71). The elastic ejector pin (7) is allowed to rebound to one side of the inclined wall after being released from the constraint; the side wall inclination angle of the inclined section (73) is the same as the inner wall inclination angle of the inclined guide hole (411), and the inclination angle is 3-7 degrees; after the elastic ejector pin (7) moves upward 25-40mm during the ejection process, its inclined section (73) completely disengages from the inclined guide hole (411) and rebounds; the rebound angle of the elastic ejector pin (7) during rebound is 5-6 degrees.

2. The elastic inclined ejector mechanism for injection molds according to claim 1, characterized in that: The elastic pin (7) is made of spring steel or titanium alloy.

3. The elastic inclined ejector mechanism for injection molds according to claim 1, characterized in that: The maximum width of the elastic pin (7) is 10.95-11.15 mm.

Images