An automatic demolding structure without a ejector pin

Abstract

The utility model discloses an automatic demoulding structure without ejector pin, which comprises an upper die plate and a lower die plate arranged oppositely, a plurality of upper cavities are arranged on the bottom surface of the upper die plate, a plurality of lower cavities corresponding to the upper cavities are arranged on the top surface of the lower die plate, a base is arranged on one side of the lower cavities on the top surface of the lower die plate, a plurality of cores are arranged on the base and extend into the upper cavities and the lower cavities, the upper cavities, the lower cavities and the cores form injection molded parts, a bottom plate is arranged below the lower die plate, and an ejection assembly is arranged between the bottom plate and the lower die plate.

Description

Technical Field

[0001] This utility model relates to the field of injection mold technology, specifically to an ejector pin-less automatic demolding structure. Background Technology

[0002] Injection molding is a method in which plastic material, completely molten at a certain temperature by a screw, is injected into a mold cavity under high pressure, and then cooled and solidified to obtain the finished product. This method is suitable for the mass production of complex-shaped parts and is one of the important processing methods. After the injection molding process is completed, demolding is usually required. For injection molded parts, if the part is a large, hollow cylinder (such as PVC drainage pipe fittings), the part needs to be arranged laterally on the mold. Existing technology first uses a side core-pulling cylinder to drive a slider to pull out the inner core, and then the ejector rod of the injection molding machine pushes the ejector plate, which drives the ejector pins to eject the core-pulled part out of the mold, thus demolding the injection molded part.

[0003] However, the above demolding method has the following drawbacks: the surface of the injection molded part ejected by the ejector pin inevitably has ejector pin marks, which causes defects on the product surface, seriously affects the product appearance, and cannot meet market demand. Utility Model Content

[0004] The purpose of this utility model is to provide an automatic demolding structure without ejector pins, which effectively solves the ejection problem of injection molded products without affecting the appearance. The injection molded products have no ejector pin marks, thus solving the problem mentioned in the background art of products with ejector pin marks left on the surface.

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

[0006] An ejector-free automatic demolding structure includes an upper mold plate and a lower mold plate arranged vertically opposite each other. The bottom surface of the upper mold plate is provided with a plurality of upper cavities, and the top surface of the lower mold plate is provided with a plurality of lower cavities adapted to the corresponding upper cavities. The top surface of the lower mold plate is provided with a base located on one side of the lower cavity. A plurality of core pullers extending into the upper and lower cavities are movably arranged on the base plate. An injection molded part is formed between the upper cavity, the lower cavity and the core pullers. A base plate is provided below the lower mold plate, and an ejector assembly is provided between the base plate and the lower mold plate.

[0007] Preferably, the ejector assembly includes an ejector plate and a plurality of ejector pins. A plurality of guide pins are connected between the base plate and the lower template. The ejector plate is movably mounted on the plurality of guide pins. The bottom end of the ejector pin is connected to the ejector plate, and the top end of the ejector pin passes upward through the lower template and connects to the bottom of the base.

[0008] Preferably, the top surface of the lower template is provided with a plurality of guide grooves corresponding to the position of the base, and a guide sleeve is embedded in each of the plurality of guide grooves, the guide sleeve being fitted on the outer circumferential surface of the top column.

[0009] Preferably, the inner circumferential surface of the guide sleeve that contacts the top post is provided with a wear-resistant layer.

[0010] Preferably, the base has a plurality of spaced slider inserts connected to its side. Each slider insert is a hollow cylinder with a shaft hole. One end of the core puller passes through the shaft hole of the base and the slider insert and extends into the injection molded part. The slider insert is connected to the injection molded part at one end relative to the base.

[0011] Preferably, the top surface of the base is provided with a downwardly recessed groove, and a lateral core-pulling assembly connected to the core-pulling mechanism is provided in the groove.

[0012] Preferably, the lateral core-pulling assembly includes a slider and a hydraulic cylinder. Two slide rails are arranged opposite each other in the slide groove. The slider is movably mounted on the two slide rails. The hydraulic cylinder is fixed on the base. One end of the piston rod of the hydraulic cylinder extends into the slide groove and is connected to the slider.

[0013] Preferably, the core puller has one end passing through the sidewall of the groove and connecting to the slider.

[0014] Preferably, the bottom surface of the upper template has an upper mounting groove located on one side of the upper cavity, and the top surface of the lower template has a lower mounting groove located on one side of the lower cavity. The upper part of the base is accommodated in the upper mounting groove, and the lower part of the base is accommodated in the lower mounting groove.

[0015] Preferably, two guide rods are vertically arranged in the lower mounting groove, and the two guide rods are arranged opposite each other on both sides of the lower mounting groove. The upper template has two sliding holes that cooperate with the two guide rods. The top ends of the two guide rods extend upward and are inserted into the corresponding sliding holes. The two side walls of the base are slidably connected to the two guide rods respectively.

[0016] Compared with the prior art, the beneficial effects of this utility model are: it eliminates the need to eject the injection molded part directly from the lower cavity using ejector pins, thus avoiding damage to the product's appearance. Instead, it only requires ejecting the injection molded part from the lower cavity using an ejector assembly, and then separating the core puller from the injection molded part, thereby completing the seamless demolding of the injection molded part. This effectively solves the problem of rapid ejection of injection molded parts without affecting their appearance. The injection molded part has no ejector pin marks, thus improving the product demolding quality. Attached Figure Description

[0017] Figure 1 This is a perspective view of an ejector pin-less automatic demolding structure according to the present invention;

[0018] Figure 2 This is a schematic diagram of the structure of the ejector pin-less automatic demolding structure after mold opening according to this utility model;

[0019] Figure 3 This is a perspective view of the lateral core-pulling assembly of this utility model;

[0020] Figure 4 This is a cross-sectional view of an ejector pin-less automatic demolding structure according to the present invention;

[0021] Figure 5 This is a cross-sectional view of the base of this utility model being lifted up by the top column;

[0022] Figure 6 This is a cross-sectional view of the core-pulling mechanism after it has been removed from the injection-molded part.

[0023] The markings in the diagram correspond to: 1. Upper template; 11. Upper cavity; 12. Upper mounting groove; 13. Sliding hole; 2. Lower template; 21. Lower cavity; 22. Lower mounting groove; 23. Guide rod; 24. Guide groove; 25. Guide sleeve; 3. Base; 31. Slider insert; 32. Connecting block; 33. Sliding groove; 4. Core pulling; 5. Injection part; 6. Base plate; 61. Guide post; 7. Ejection assembly; 72. Ejector plate; 73. Ejector post; 8. Side core pulling assembly; 81. Slider; 82. Hydraulic cylinder. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0025] Please see Figure 1-3 An ejector-free automatic demolding structure includes an upper mold plate 1 and a lower mold plate 2 arranged vertically opposite each other. The bottom surface of the upper mold plate 1 has several upper cavities 11, and the top surface of the lower mold plate 2 has several lower cavities 21 adapted to the corresponding upper cavities 11. A base 3 located on one side of the lower cavities 21 is provided on the top surface of the lower mold plate 2. Several core-pulling components 4 extending into the upper cavities 11 and lower cavities 21 are movably disposed on the base 3, forming injection molded parts 5 between the upper cavities 11, lower cavities 21, and core-pulling components 4. A base plate 6 is provided below the lower mold plate 2, and an ejector assembly 7 is provided between the base plate 6 and the lower mold plate 2. One end of the ejector assembly 7 passes upward through the lower mold plate 2 and connects to the base 3, for ejecting the base 3 from the top surface of the lower mold plate 2.

[0026] Please see Figure 2 , Figure 5 as well as Figure 6After the injection molded part 5 is formed, the upper mold plate 1 and the lower mold plate 2 separate, completing the mold opening action. Then, the ejector assembly 7 lifts the base 3, the core puller 4, and the injection molded part 5 upwards, causing the injection molded part 5 to detach from the lower cavity 21 of the lower mold plate 2. Next, the core puller 4 is pulled out from the injection molded part 5, separating the core puller 4 from the injection molded part 5, thus completing the demolding. This utility model eliminates the need for ejector pins in the prior art to directly eject the injection molded part 5 from the lower cavity 21, avoiding damage to the product's appearance. Instead, it only requires ejector assembly 7 to eject the injection molded part 5 from the lower cavity 21, and then separate the core puller 4 from the injection molded part 5, thus completing the seamless demolding of the injection molded part 5. This effectively solves the problem of rapid ejection of the injection molded part 5 without affecting its appearance. There are no ejector pin marks on the injection molded part 5, improving the product demolding quality.

[0027] Please see Figure 4 The upper template 1 has an upper mounting groove 12 on its bottom surface, located on one side of the upper cavity 11, and the lower template 2 has a lower mounting groove 22 on its top surface, located on one side of the lower cavity 21. The upper part of the base 3 is accommodated in the upper mounting groove 12, and the lower part of the base 3 is accommodated in the lower mounting groove 22. The arrangement of the upper mounting groove 12 and the lower mounting groove 22 allows the base 3 to be largely accommodated within both the upper template 1 and the lower template 2, resulting in a more compact structure.

[0028] In this embodiment, please refer to Figure 2 Two guide rods 23 are vertically installed within the lower mounting groove 22, with the two guide rods 23 positioned opposite each other on both sides of the lower mounting groove 22. The upper template 1 has two sliding holes 13 that mate with the two guide rods 23. The top ends of the two guide rods 23 extend upwards and are inserted into the corresponding sliding holes 13. The two side walls of the base 3 are slidably connected to the two guide rods 23. The two guide rods 23 have a positioning function for the base 3. The arrangement of the two guide rods 23 ensures that the base 3 is accurately guided during the lifting process, preventing the base 3 from shifting during vertical movement.

[0029] Please see Figure 1 and Figure 4 The ejector assembly 7 includes an ejector plate 72 and several ejector pins 73. Several guide pins 61 connect the base plate 6 and the lower template 2. The ejector plate 72 is movably mounted on the guide pins 61. The bottom end of each ejector pin 73 is connected to the ejector plate 72, and the top end of each ejector pin 73 passes upward through the lower template 2 and connects to the bottom of the base 3. In this embodiment, the base plate 6 or the lower template 2 is provided with a driving mechanism (not shown) for driving the ejector plate 72 to move up and down. The driving mechanism can be a hydraulic cylinder.

[0030] Please see Figure 4The top surface of the lower template 2, corresponding to the position of the base 3, has several guide grooves 24. Each guide groove 24 contains a guide sleeve 25, which is fitted onto the outer circumferential surface of the top post 73. In this embodiment, the inner circumferential surface of the guide sleeve 25 in contact with the top post 73 is provided with a wear-resistant layer. By setting the guide post 61 and guide sleeve 25, the ejector plate 72 is accurately guided when moving up and down, preventing the top post 73 from shifting, resulting in a stable and reliable structure. The wear-resistant layer on the guide sleeve 25 reduces friction between the guide post 61 and the guide sleeve 25, thereby extending the service life of the guide post 61. Furthermore, the guide post 61 and guide sleeve 25 are easy to replace, facilitating later maintenance.

[0031] Please see Figure 3 as well as Figure 4 The base 3 has several spaced-apart slider inserts 31 connected to its side. Each slider insert 31 is a hollow cylinder with a shaft hole. One end of the core puller 4 passes through the shaft hole of the base 3 and the slider insert 31 and extends into the injection molded part 5 to cooperate with the molding of the injection molded part 5. The slider insert 31 is connected to the injection molded part 5 at one end relative to the base 3. A connecting block 32 is provided on the side of the base 3. One end of each slider insert 31 is fixed to the side of the connecting block 32. The connecting block 32 has several guide holes communicating with the shaft holes of the slider insert 31 to allow the core puller 4 to pass through.

[0032] Please see Figure 3 The base 3 has a downwardly recessed groove 33 on its top surface. A lateral core-pulling assembly 8, connected to the core-pulling component 4, is disposed within the groove 33. The lateral core-pulling assembly 8 includes a slider 81 and a hydraulic cylinder 82. Two slide rails are arranged opposite each other within the groove 33. The slider 81 is movably mounted on the two slide rails. The hydraulic cylinder 82 is fixed to the base 3, and one end of the piston rod of the hydraulic cylinder 82 extends into the groove 33 and connects to the slider 81. In this embodiment, the end of the core-pulling component 4 opposite to the injection-molded part 5 passes through the side wall of the groove 33 and connects to the slider 81.

[0033] The working principle of this novel pinless automatic demolding structure is as follows: Figure 2 As shown, after the injection molded part 5 is formed, the mold opening action is performed first. At this time, the upper mold plate 1 and the lower mold plate 2 separate, exposing the injection molded part 5, as shown. Figure 5 As shown, demolding then occurs. The ejector plate 72 moves upward under the drive mechanism, and the ejector plate 72 drives the ejector pin 73 to push the base 3 out from the top surface of the lower mold plate 2. At this time, the slider 81, hydraulic cylinder 82, slider insert 31, and core puller 4 on the base 3 are ejected together with the base 3, and the injection molded part 5 is also pulled out of the lower cavity 21 along with the core puller 4; as shown... Figure 6As shown, the hydraulic cylinder 82 then drives the slider 81 to retract via the piston rod. The slider 81 drives the core puller 4 to be pulled out of the injection molded part 5. At this time, the base 3, the slider insert 31, and the injection molded part 5 remain stationary. When the core puller 4 is completely pulled out of the injection molded part 5, the core puller 4 action is completed. At this time, the injection molded part 5 can be removed from the slider insert 31 manually or by a robot. The entire demolding process can achieve the purpose of product demolding without ejector pins, which meets customer needs and achieves a product appearance without marks.

[0034] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A pinless automatic demolding structure, comprising an upper mold plate (1) and a lower mold plate (2) arranged vertically opposite each other, wherein the bottom surface of the upper mold plate (1) is provided with a plurality of upper cavities (11), and the top surface of the lower mold plate (2) is provided with a plurality of lower cavities (21) adapted to the corresponding upper cavities (11), characterized in that: The lower template (2) has a base (3) located on one side of the lower cavity (21) on its top surface. Several core pullers (4) extending into the upper cavity (11) and the lower cavity (21) are movably arranged on the base (3). An injection molded part (5) is formed between the upper cavity (11), the lower cavity (21) and the core pullers (4). A bottom plate (6) is provided below the lower template (2). An ejection assembly (7) is provided between the bottom plate (6) and the lower template (2).

2. The ejector-less automatic demolding structure according to claim 1, characterized in that: The ejector assembly (7) includes an ejector plate (72) and several ejector pins (73). Several guide pins (61) are connected between the base plate (6) and the lower template (2). The ejector plate (72) is movably mounted on several guide pins (61). The bottom end of the ejector pin (73) is connected to the ejector plate (72). The top end of the ejector pin (73) passes upward through the lower template (2) and connects to the bottom of the base (3).

3. The ejector-less automatic demolding structure according to claim 2, characterized in that: The lower template (2) has several guide grooves (24) on its top surface corresponding to the base (3). Each of the guide grooves (24) is fitted with a guide sleeve (25), which is fitted onto the outer circumference of the top column (73).

4. The ejector-less automatic demolding structure according to claim 3, characterized in that: The inner circumferential surface of the guide sleeve (25) that contacts the top column (73) is provided with a wear-resistant layer.

5. The ejector-less automatic demolding structure according to claim 1, characterized in that: The base (3) has several spaced slider inserts (31) connected to its side. The slider insert (31) is a hollow cylinder with a shaft hole. One end of the core puller (4) passes through the shaft hole of the base (3) and the slider insert (31) and extends into the injection molded part (5). The slider insert (31) is connected to the injection molded part (5) at one end relative to the base (3).

6. The ejector-less automatic demolding structure according to any one of claims 1-5, characterized in that: The base (3) has a downwardly recessed groove (33) on its top surface, and a lateral core-pulling assembly (8) connected to the core-pulling (4) is provided in the groove (33).

7. The ejector-less automatic demolding structure according to claim 6, characterized in that: The lateral core-pulling assembly (8) includes a slider (81) and a hydraulic cylinder (82). Two slide rails are arranged opposite each other in the slide groove (33). The slider (81) is movably arranged on the two slide rails. The hydraulic cylinder (82) is fixed on the base (3). One end of the piston rod of the hydraulic cylinder (82) extends into the slide groove (33) and is connected to the slider (81).

8. The ejector-less automatic demolding structure according to claim 7, characterized in that: The core puller (4) passes through the side wall of the groove (33) and connects to the slider (81) at one end relative to the injection molded part (5).

9. The ejector pinless automatic demolding structure according to claim 1, characterized in that: The bottom surface of the upper template (1) is provided with an upper mounting groove (12) located on one side of the upper cavity (11), and the top surface of the lower template (2) is provided with a lower mounting groove (22) located on one side of the lower cavity (21). The upper part of the base (3) is accommodated in the upper mounting groove (12), and the lower part of the base (3) is accommodated in the lower mounting groove (22).

10. The ejector-less automatic demolding structure according to claim 9, characterized in that: Two guide rods (23) are upright in the lower mounting groove (22). The two guide rods (23) are arranged opposite each other on both sides of the lower mounting groove (22). The upper template (1) has two sliding holes (13) that cooperate with the two guide rods (23). The top ends of the two guide rods (23) extend upward and are inserted into the corresponding sliding holes (13). The two side walls of the base (3) are slidably connected to the two guide rods (23).

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