Limited space inverted draw demolding structure

Abstract

The utility model provides a limited space reverse buckle demolding structure, including setting dynamic drawing board, the boss cylinder ejection mechanism and bottom plate in proper order. Dynamic drawing board bottom is equipped with the sliding slot. The boss cylinder ejection mechanism includes: sliding plate, sliding plate slidingly arranged in the sliding slot, and the preset gap between the sliding plate top surface and the sliding slot bottom surface. The top plate subassembly, the top plate subassembly includes the thimble face plate, the thimble middle plate and the thimble bottom plate. At least one support column, the support column lower end fixed connection in the thimble bottom plate, and its top end abuts in the sliding plate bottom surface. At least one boss cylinder, the top of boss cylinder is equipped with the reverse buckle forming part of radial elastic tension shrink, is used for the reverse buckle feature of the shaped product. The boss cylinder is equipped with the sliding hole of through along its axial direction. At least one first thimble, at least one second thimble. The bottom plate is fixedly connected with the boss cylinder needle. The utility model can complete the demolding of reverse buckle without additional lateral drive mechanism, effectively simplifies the mould structure, reduces the interference risk, improves the demolding efficiency and product qualification rate.

Description

Technical Field

[0001] This utility model belongs to the field of injection mold technology, specifically relating to a limited space undercut demolding structure. Background Technology

[0002] In injection molds, for products with complex geometries such as undercuts, additional core-pulling mechanisms or angled ejector structures are typically introduced to address the demolding problem of the undercut area. During demolding, an independent slider core-pulling mechanism can be used to complete lateral parting or core pulling during mold opening, followed by the ejection operation. Alternatively, an angled ejector can be used to simultaneously perform lateral displacement, thus detaching from the undercut area. Angled ejector mechanisms require sufficient ejection stroke and angular space, are prone to interference in deep-cavity, thin-walled, or densely packed molds, and have limited lateral core-pulling distance. Independent slider mechanisms, on the other hand, require additional installation space and a drive system, increasing mold complexity and manufacturing costs, and may also lead to ejection collisions or product damage due to uncoordinated action sequences. Both of these solutions face challenges in space-constrained mold layouts.

[0003] Therefore, the above problems urgently need to be solved. Utility Model Content

[0004] Purpose of the utility model: In order to overcome the above shortcomings, this utility model provides a limited space undercut demolding structure, which can complete the undercut demolding without an additional driving mechanism within a limited mold space, effectively simplifying the mold structure, reducing the risk of interference, and improving demolding efficiency and product qualification rate.

[0005] Technical Solution: To achieve the above objectives, this utility model provides a limited-space undercut demolding structure, comprising a moving template, an ejector sleeve mechanism, and a base plate arranged sequentially. The moving template has a groove at its bottom. The ejector sleeve mechanism includes: The skateboard is mounted in a groove, and there is a preset gap between the top surface of the skateboard and the bottom surface of the groove.

[0006] Top plate assembly; The top plate assembly is located below the slide plate and includes a pin front panel, a pin middle plate, and a pin base plate stacked from top to bottom.

[0007] At least one support column; the lower end of the support column is fixedly connected to the ejector plate, and the support column passes through the ejector panel and the ejector middle plate. The top of the support column abuts against the bottom surface of the slide plate.

[0008] At least one ejector sleeve; the lower end of the ejector sleeve is fixedly connected to the top surface of the slide plate and passes upward through the moving template. The top of the ejector sleeve is provided with a radially elastically expandable undercut forming part for the undercut feature of the molded product. The ejector sleeve is provided with a through sliding hole along its axial direction.

[0009] At least one first ejector pin. The first ejector pin is fixed to the ejector pin panel and / or the ejector pin middle plate; the upper end of the first ejector pin passes upward through the slide plate and the moving template.

[0010] At least one second ejector pin. The lower end of the second ejector pin is fixedly connected to the slide plate. The upper end of the second ejector pin passes upward through the moving template.

[0011] At least one ejector pin is fixedly connected to the base plate; in the mold closed state, the ejector pin passes through the sliding hole and extends into the undercut forming part, and forms radial support for the undercut forming part.

[0012] This invention relates to an ejection mechanism used in injection molds. During ejection, the ejector plate assembly moves upward under external driving force, which in turn pushes the ejector plate, ejector middle plate, and ejector base plate upward simultaneously. At this time, the support column fixed to the ejector base plate also moves upward. Because the top of the support column abuts against the bottom surface of the slide plate, and there is a preset gap between the slide plate and the bottom surface of the groove, the slide plate first slides upward along the groove under the push of the support column, causing the ejector sleeve and the second ejector pin fixed to it to rise synchronously. The first ejector pin, fixed to the ejector plate and / or the ejector middle plate, also rises synchronously. The ejector sleeve, the first ejector pin, and the second ejector pin together push the product away from the moving mold plate. As the ejector sleeve rises, the ejector pin slides downward relative to the ejector sleeve, gradually exiting the undercut molding part, and the ejector pin exits the product. As the ejector plate assembly continues to move upward, when the top surface of the slide plate is in contact with the bottom surface of the groove and the preset gap is eliminated, the slide plate stops sliding. At this point, the ejector plate and ejector middle plate continue to move upward, and the first ejector continues to move upward, causing the undercut forming part to undergo elastic deformation and separate from the undercut feature of the product.

[0013] This invention achieves demolding of undercut without additional lateral drive mechanism within a limited mold space by using a step-by-step ejection design of the slide plate and top plate assembly, as well as the cooperation between the ejector pin and the elastic undercut forming part. This effectively simplifies the mold structure, reduces the risk of interference, and improves demolding efficiency and product qualification rate.

[0014] Furthermore, in the aforementioned limited-space undercut demolding structure, the ejector base plate is wider than the ejector panel and the ejector middle plate on both sides. Angle irons are provided between the moving template and the base plate, with two angle irons arranged parallel to each other on both sides of the ejector base plate. Limiting grooves are provided on opposite sides of the two angle irons, and the two sides of the ejector base plate are slidably connected to the limiting grooves. The upper surface of the limiting groove restricts the maximum ejection stroke of the ejector base plate. This invention limits the maximum ejection stroke of the ejector base plate by using limiting grooves, preventing collisions caused by excessive ejection, ensuring precise and controllable movement of the slide plate and the top plate assembly, and improving the stability and safety of the demolding process. In addition, the angle irons also guide the lateral displacement of the top plate assembly, preventing displacement during ejection and ensuring the accuracy of the ejection actions of the ejector sleeve, the first ejector pin, and the second ejector pin.

[0015] Furthermore, in the aforementioned limited-space undercut demolding structure, the undercut forming part includes a cylindrical forming cavity, and the sidewall of the forming cavity is provided with an arc-shaped recess for forming the undercut part. The curvature of the arc-shaped recess matches the inner curved surface of the undercut feature of the product to ensure that the undercut forming part can accurately replicate the undercut structure of the product.

[0016] Furthermore, in the aforementioned confined space undercut demolding structure, a guide surface is provided at the upper opening of the molding cavity, and the guide surface is arranged around the circumference of the molding cavity opening. The guide surface can guide the melt to flow smoothly into the molding cavity during injection molding, reduce melt flow resistance and eddy currents, and avoid molding defects caused by melt impact.

[0017] Furthermore, in the aforementioned limited-space undercut demolding structure, the undercut forming part is provided with multiple axially extending deformation grooves. These grooves are evenly arranged around the axis of the undercut forming part, dividing it into multiple independently radially deformable flaps. Dividing the undercut forming part into multiple flaps allows for uniform radial deformation when the undercut forming part and the undercut part of the product separate, avoiding elastic failure or breakage caused by localized stress concentration, ensuring consistent deformation of each flap, and allowing the undercut feature of the product to detach uniformly from the arc-shaped recess, thus reducing demolding resistance.

[0018] Furthermore, in the aforementioned limited-space undercut demolding structure, deformation holes are provided at the ends of multiple deformation grooves. The setting of deformation holes can further enhance the elastic deformation capability of the deformation flap, ensuring that the deformation flap undergoes elastic deformation outward, forming sufficient clearance space, and avoiding damage to the undercut part of the product.

[0019] Furthermore, in the aforementioned confined space undercut demolding structure, the ejector sleeve sidewall is provided with a pressure relief hole. This hole connects the sliding hole to the outside of the ejector sleeve. The pressure relief hole balances the air pressure within the sliding hole, preventing negative pressure caused by the ejector sleeve pin sliding from affecting the smoothness of demolding.

[0020] As can be seen from the above technical solution, this utility model has the following beneficial effects: The limited space undercut demolding structure of this utility model, through the step-by-step ejection design of the slide plate and top plate assembly, and the cooperation between the ejector pin and the elastic undercut forming part, realizes the undercut demolding without the need for an additional lateral drive mechanism in the limited mold space, effectively simplifying the mold structure, reducing the risk of interference, and improving demolding efficiency and product qualification rate. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the confined space undercut demolding structure of this utility model; Figure 2 This is a top view of the confined space undercut demolding structure of this utility model; Figure 3 for Figure 2 The sectional view shown is along line AA. Figure 4 for Figure 2 The BB-directed sectional view shown Figure 5 This is a schematic diagram of the ejector sleeve mechanism; Figure 6 This is a sectional view along the axis of the ejector sleeve mechanism; Figure 7 for Figure 6 The image shows a magnified view of a portion of the molding cavity. Figure 8 for Figure 5 The enlarged view of the undercut molding part shown.

[0022] In the diagram: 1. Moving template, 11. Slide groove, 2. Ejector sleeve ejection mechanism, 21. Slide plate, 22. Top plate assembly, 221. Ejector pin panel, 222. Ejector pin middle plate, 223. Ejector pin bottom plate, 23. Ejector sleeve, 231. Inverted forming part, 2311. Forming cavity, 2312. Arc-shaped concave part, 2313. Guide arc surface, 232. Sliding hole, 233. Deformation flap, 234. Deformation hole, 235. Pressure relief hole, 236. Deformation groove, 24. Support column, 25. First ejector pin, 26. Second ejector pin, 3. Base plate, 31. Ejector sleeve pin, 4. Angle iron, 41. Limiting groove. Detailed Implementation

[0023] Example 1 like Figure 1-6 The diagram illustrates a confined space undercut demolding structure, comprising a movable template 1, an ejector sleeve mechanism 2, and a base plate 3 arranged sequentially. The movable template 1 has a groove 11 at its bottom. The ejector sleeve mechanism 2 includes: Slide 21; Slide 21 is slidably disposed in slide groove 11, and there is a preset gap between the top surface of slide 21 and the bottom surface of slide groove 11.

[0024] Top plate assembly 22; Top plate assembly 22 is disposed below slide plate 21. Top plate assembly 22 includes ejector pin panel 221, ejector pin middle plate 222 and ejector pin base plate 223 stacked from top to bottom.

[0025] At least one support column 24; the lower end of the support column 24 is fixedly connected to the ejector base plate 223, and the support column 24 is set through the ejector panel 221 and the ejector middle plate 222. The top end of the support column 24 abuts against the bottom surface of the slide plate 21.

[0026] At least one ejector sleeve 23; the lower end of the ejector sleeve 23 is fixedly connected to the top surface of the slide plate 21 and passes upward through the moving template 1. The top of the ejector sleeve 23 is provided with a radially elastically expandable undercut forming part 231 for forming the undercut feature of the molded product. The ejector sleeve 23 is provided with a through sliding hole 232 along its axial direction.

[0027] At least one first ejector pin 25. The first ejector pin 25 is fixed to the ejector plate 221 and / or the ejector middle plate 222; the upper end of the first ejector pin 25 passes upward through the slide plate 21 and the moving template 1. The first ejector pin 25 is inserted into the countersunk through hole provided in the ejector plate 221, and the bottom end of the first ejector pin 25 abuts against the ejector middle plate 222, which keeps the first ejector pin 25 in the countersunk through hole provided in the ejector plate 221.

[0028] At least one second ejector pin 26. The lower end of the second ejector pin 26 is fixedly connected to the slide plate 21. The upper end of the second ejector pin 26 passes upward through the moving template 1.

[0029] At least one ejector pin 31 is fixedly connected to the base plate 3; in the mold closed state, the ejector pin 31 passes through the sliding hole 232 and extends into the undercut forming part 231, and forms radial support for the undercut forming part 231.

[0030] like Figure 4 The confined space undercut demolding structure shown has an ejector base plate 223 wider than the ejector panel 221 and the ejector middle plate 222 on both sides. Angle irons 4 are provided between the moving template 1 and the base plate 3, with two angle irons 4 arranged parallel to each other on both sides of the ejector base plate 223. Limiting grooves 41 are provided on opposite sides of the two angle irons 4, and both sides of the ejector base plate 223 are slidably connected to the limiting grooves 41. The upper surface of the limiting grooves 41 limits the maximum ejection stroke of the ejector base plate 223.

[0031] like Figure 7 The limited-space undercut demolding structure shown includes an undercut forming part 231 comprising a cylindrical forming cavity 2311, with an arc-shaped recess 2312 surrounding the sidewall of the forming cavity 2311 for forming the undercut part. The curvature of the arc-shaped recess 2312 matches the inner curved surface of the undercut feature of the product, ensuring that the undercut forming part 231 can accurately replicate the undercut structure of the product.

[0032] In this embodiment, a guide surface 2313 is provided at the upper opening of the molding cavity 2311, and the guide surface 2313 is arranged around the circumference of the opening of the molding cavity 2311. The guide surface 2313 can guide the melt to flow smoothly into the molding cavity 2311 during the injection molding process, reduce melt flow resistance and eddy current phenomenon, and avoid molding defects caused by melt impact.

[0033] like Figure 8The confined space undercut demolding structure shown has an undercut forming part 231 with multiple axially extending deformation grooves 236. These grooves are evenly arranged around the axis of the undercut forming part 231, dividing it into multiple independently radially deformable deformation petals 233. Dividing the undercut forming part 231 into multiple deformation petals 233 allows for uniform radial deformation when the undercut forming part 231 separates from the undercut part of the product, avoiding elastic failure or fracture caused by localized stress concentration. This ensures consistent deformation of each deformation petal 233, allowing the undercut feature of the product to detach evenly from the arc-shaped recess 2312 and reducing demolding resistance.

[0034] In this embodiment, each of the multiple deformation grooves 236 has a deformation hole 234 at its end.

[0035] like Figure 6 The confined space undercut demolding structure shown has a pressure relief hole 235 on the side wall of the ejector sleeve 23. The pressure relief hole 235 connects the sliding hole 232 and the outside of the ejector sleeve 23.

[0036] Working Principle: At the start of the ejection process, the injection molding machine's ejector rod pushes the entire ejector plate assembly 22 upwards. The ejector base plate 223, via the support column 24 fixed thereon, pushes the slide plate 21 upwards. Due to a preset gap, the slide plate 21 (along with the ejector sleeve 23 and the second ejector pin 26 fixed thereon) can move freely upwards a certain distance before contacting the bottom surface of the slide groove 11. At this time, the ejector sleeve 23 slides upwards relative to the ejector pin 31 fixed to the base plate 3, the ejector pin 31 pulls the core out of the product, and the undercut part of the product gradually separates from the ejector pin 31. During this stage, the ejector plate 221, the ejector middle plate 222, and the ejector base plate 223 move synchronously as a whole, and the first ejector pin 25, the second ejector pin 26, and the ejector sleeve 23 together completely eject the product from the cavity of the moving template 1. The undercut forming part 231 of the ejector sleeve 23 still maintains the undercut part of the product.

[0037] When the ejector base plate 223 moves upward until its sides are blocked by the upper end face of the limiting groove 41 of the angle iron 4, it stops moving. Simultaneously, the slide plate 21, ejector sleeve 23, and second ejector pin 26 connected to it via the support column 24 also stop. The injection molding machine ejector rod continues to act, causing the ejector plate 221 and ejector middle plate 222 to continue moving upward, and the first ejector pin 25 to continue moving upward, compressing the undercut portion of the product into deformation petals 233. Each deformation petal 233 undergoes elastic deformation outward under compression, forming clearance space, until the undercut portion of the product completely separates from the undercut forming portion 231, completing the final demolding.

[0038] During reset, the three layers of the top plate assembly 22 are reset as one unit, and then the entire ejector sleeve ejection mechanism 2 is driven back to its original position. The ejector sleeve pin 31 is re-inserted into the undercut forming part 231 to prepare for the next forming cycle.

[0039] The above embodiments are exemplary and are intended to illustrate the technical concept and features of this utility model, so that those skilled in the art can understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be covered within the scope of protection of this utility model.

Claims

1. A limited-space undercut demolding structure, characterized in that: It includes a movable template (1), a sleeve ejection mechanism (2), and a base plate (3) arranged sequentially; the movable template (1) has a groove (11) at its bottom; the sleeve ejection mechanism (2) includes: Slide plate (21); the slide plate (21) is slidably disposed in the slide groove (11), and there is a preset gap between the top surface of the slide plate (21) and the bottom surface of the slide groove (11); Top plate assembly (22); The top plate assembly (22) is disposed below the slide plate (21), and the top plate assembly (22) includes a pin panel (221), a pin middle plate (222) and a pin bottom plate (223) stacked from top to bottom. At least one support column (24); the lower end of the support column (24) is fixedly connected to the ejector base plate (223), and the support column (24) is set through the ejector panel (221) and the ejector middle plate (222); the top end of the support column (24) abuts against the bottom surface of the slide plate (21); At least one sleeve (23); the lower end of the sleeve (23) is fixedly connected to the top surface of the slide plate (21) and passes upward through the moving template (1); the top of the sleeve (23) is provided with a radially elastically expandable undercut forming part (231) for forming the undercut feature of the product; the sleeve (23) is provided with a through sliding hole (232) along its axial direction. At least one first ejector pin (25); the first ejector pin (25) is fixed to the ejector pin panel (221) and / or the ejector pin middle plate (222); the upper end of the first ejector pin (25) passes upward through the slide plate (21) and the moving template (1); At least one second ejector pin (26); the lower end of the second ejector pin (26) is fixedly connected to the slide plate (21); the upper end of the second ejector pin (26) passes upward through the moving template (1); At least one ejector pin (31) is fixedly connected to the base plate (3); in the mold closing state, the ejector pin (31) passes through the sliding hole (232) and extends into the undercut forming part (231), and forms radial support for the undercut forming part (231).

2. The confined space undercut demolding structure according to claim 1, characterized in that: The ejector base plate (223) is wider than the ejector panel (221) and the ejector middle plate (222) on both sides; an angle iron (4) is provided between the moving template (1) and the base plate (3), and the two angle irons (4) are arranged parallel to each other on both sides of the ejector base plate (223); a limiting groove (41) is provided on the opposite side of the two angle irons (4), and the two sides of the ejector base plate (223) are slidably connected in the limiting groove (41); the upper end face of the limiting groove (41) limits the maximum ejection stroke of the ejector base plate (223).

3. The confined space undercut demolding structure according to claim 1, characterized in that: The undercut forming part (231) includes a cylindrical forming cavity (2311), and the sidewall of the forming cavity (2311) is provided with an arc-shaped recess (2312) for forming the undercut part.

4. The confined space undercut demolding structure according to claim 3, characterized in that: The upper opening of the molding cavity (2311) is provided with a guide surface (2313), which is arranged around the circumference of the opening of the molding cavity (2311).

5. The confined space undercut demolding structure according to claim 4, characterized in that: The undercut forming part (231) is provided with a plurality of axially extending deformation grooves (236); the plurality of deformation grooves (236) are evenly arranged around the axis of the undercut forming part (231), and the deformation grooves (236) divide the undercut forming part (231) into a plurality of deformation lobes (233) that can be independently radially deformed.

6. The confined space undercut demolding structure according to claim 5, characterized in that: Each of the multiple deformation grooves (236) is provided with a deformation hole (234) at its end.

7. The confined space undercut demolding structure according to claim 1, characterized in that: The side wall of the sleeve (23) is provided with a pressure relief hole (235); the pressure relief hole (235) connects the sliding hole (232) and the outside of the sleeve (23).

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