Injection molding device for electric melting pipe fitting

Abstract

The utility model discloses an electrofusion pipe fitting injection molding device which comprises a lower mold, an upper mold, a side core mold and cover closing plates, the upper mold and the lower mold are mutually fixed in a cover closing mode, the side core mold is arranged in a central area between the upper mold and the lower mold, and the cover closing plates are fixedly connected to the two ends of the side core mold respectively. The cover closing plates are connected to the two sides of the upper mold and the two sides of the lower mold in a closed mode respectively, a section mold cavity used for injection molding of the electric melting pipe fitting is formed among the upper mold, the lower mold, the side core molds and the cover closing plates, two sets of embedding holes are formed in the inner side wall of the section mold cavity, the embedding holes are all located between the upper mold and the lower mold, and cover cap barrels are connected into the embedding holes in an embedded mode; a binding post is inserted into the cap cylinder, the other end of the binding post is connected with an electric heating wire, and the electric heating wire is evenly wound and connected to the two sides of the side core mold. The utility model aims to provide the injection molding device for the electric melting pipe fitting, which is reasonable in structure, accurate in positioning and convenient to maintain.

Description

Technical Field

[0001] This utility model relates to the field of electrofusion pipe fitting forming technology, specifically an electrofusion pipe fitting injection molding device. Background Technology

[0002] Electrofusion fittings are key connecting components widely used in plastic piping systems. They achieve a reliable socket connection with the pipe by melting the polymer layer on the inner wall of the fitting through a built-in heating wire. Currently, electrofusion fittings are mainly manufactured using injection molding, but the following technical problems still exist in actual production:

[0003] 1. Heating wire positioning and sealing issues: In traditional molds, the winding position of the heating wire is prone to misalignment during injection molding, leading to uneven heating of the inner wall of the fitting and affecting the stability of electrofusion performance. Furthermore, insufficient sealing of the terminals allows molten plastic to easily seep into the wiring cavity, causing short circuits or poor contact, thus reducing product yield.

[0004] 2. Insufficient alignment accuracy of side core type: In order to improve production efficiency, molds are usually designed in a split manner. However, the side core type is prone to misalignment when the mold is closed, which leads to inaccurate forming of the inner wall structure of the pipe (such as the socket), and even produces flash defects, affecting the sealing performance.

[0005] 3. Complex mold maintenance and assembly: The side core is a vulnerable part that needs to be replaced or maintained regularly. However, the disassembly and assembly process of traditional molds is cumbersome and lacks a reliable reset mechanism, resulting in the side core not fitting tightly and affecting the consistency of pipe dimensions. Utility Model Content

[0006] In view of the above-mentioned shortcomings in the existing technology, the purpose of this utility model is to provide an electrofusion tube injection molding device with reasonable structure, accurate positioning and easy maintenance.

[0007] The technical solution adopted by this utility model to achieve the above objectives is as follows: an injection molding device for electrofusion pipe fittings, comprising a lower mold, an upper mold, a side core, and a cover plate. The upper mold and the lower mold are mutually closed and fixed. A side core is provided in the central area between the upper mold and the lower mold. Cover plates are fixedly connected to both ends of the side core. The cover plates are respectively closed and connected to both sides of the upper mold and the lower mold. A mold cavity for injection molding electrofusion pipe fittings is formed between the upper mold, the lower mold, the side core, and the cover plate. Two sets of fitting holes are provided on the inner sidewall of the mold cavity. The fitting holes are all located between the upper mold and the lower mold. A cap cylinder is nested in the fitting hole. A terminal is inserted into the cap cylinder. The other end of the terminal is connected to an electric heating element. The heating wires are evenly wound and connected to both sides of the side core. In this invention, the upper or lower mold has an injection hole that passes through the mold cavity. The upper and lower molds are designed separately to facilitate mold opening, part removal, and maintenance. After the mold is closed, mechanical fixing (such as bolts) ensures stability during the injection molding process. The side core is located in the central area between the upper and lower molds, and its two ends are fixed by cover plates. It is used to form the inner wall structure of the pipe fitting (such as the socket part of the electrofusion interface). The heating wires are evenly wound on both sides of the side core. After being energized, they directly heat the inner wall of the pipe fitting to form a weldable polymer layer, thereby realizing the electrofusion function. The fitting hole is opened in the inner wall of the mold cavity to fix the cap cylinder. A terminal is connected inside the cap cylinder to prevent the plastic melt from seeping into the cap cylinder.

[0008] In the above technical solution, several mutually symmetrical mounting grooves are respectively opened on both sides of the upper mold and the lower mold, and mounting holes are respectively opened on the opposite side of the mounting grooves. The bolts pass through the mounting holes in sequence and are threadedly connected to the nuts.

[0009] In the above technical solution, the side core includes a left core and a right core, and one end of the left core and the right core are attached to each other.

[0010] In the above technical solution, a sliding guide hole is provided on the end face of the left core, and a sliding groove hole is provided at the bottom of the sliding guide hole. A sliding block is slidably connected in the sliding groove hole. A guide rod is fixedly connected to one side of the sliding block. A guide hole is provided on the bottom surface of the sliding groove hole. The guide rod is slidably connected in the guide hole. A helical spring is sleeved on the guide rod in the sliding groove hole. One end of the helical spring abuts against the bottom surface of the sliding groove hole, and the other end of the helical spring abuts against the sliding block. A sliding guide post is fixedly connected to the other side of the sliding block. The sliding guide post is slidably connected in the sliding guide hole. A slot block is fixedly connected to the other end of the sliding guide post. A slot hole is provided on the right core of one side of the slot block, and the slot block is inserted into the slot hole.

[0011] In the above technical solution, several positioning pins are fixedly connected to the right core around the slot hole, and a positioning pin hole is opened on the sliding guide post on one side of the positioning pin, and the positioning pin is inserted into the positioning pin hole.

[0012] In the above technical solution, through holes are respectively opened at the four corners of the cover plate, and threaded holes are respectively opened on the upper mold and the lower mold on the opposite side of the through holes. After the screw passes through the through hole, it is threaded into the threaded hole.

[0013] The beneficial effects of this utility model are:

[0014] 1. By setting fitting holes in the inner wall of the mold cavity and nesting cap sleeves, the connection between the terminal block and the heating wire is sealed reliably, effectively preventing the plastic melt from seeping in and avoiding short circuits or poor contact problems.

[0015] 2. The heating wire is evenly wound on both sides of the side core, combined with a precise interlocking structure, which makes the heating more uniform and improves the welding stability and sealing performance of the electrofusion fitting.

[0016] 3. It adopts a split side core design (left core and right core), combined with sliding guide pillars, slot blocks and positioning pins to achieve automatic and precise alignment, avoiding molding defects caused by mold misalignment.

[0017] 4. The synergistic effect of the helical spring and the guide rod ensures that the side core fits tightly when the mold is closed, ensuring the dimensional consistency of the inner wall structure of the pipe fitting (such as the socket) and reducing the generation of flash.

[0018] 5. The upper and lower molds adopt a split bolt fixing structure, with a detachable cover plate, which simplifies the replacement and maintenance process of the side core and reduces downtime; the sliding fit design of the slide block and guide hole makes the disassembly and assembly of the side core more convenient, while the spring return function ensures the stability after repeated assembly.

[0019] 6. The overall structural design takes into account both injection molding stability and demolding convenience, reducing manual adjustment steps and shortening the production cycle; through precise cavity forming and heating wire layout, the scrap rate is greatly reduced, making it suitable for mass production of high-precision electrofusion fittings. Attached Figure Description

[0020] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0021] Figure 2 This is a schematic diagram of the disassembled structure of this utility model;

[0022] Figure 3 This is a top view of the lower mold structure of this utility model;

[0023] Figure 4This is a schematic diagram of the core-shaped cross-sectional structure on the left side of this utility model;

[0024] Figure 5 This is a schematic diagram of the core structure on the right side of this utility model.

[0025] In the diagram: 1 Lower mold, 2 Upper mold, 3 Side core, 4 Cover plate, 5 Mold cavity, 6 Fitting hole, 7 Cap sleeve, 8 Terminal post, 9 Heating wire, 10 Mounting groove, 11 Mounting hole, 12 Nut, 13 Left core, 14 Right core, 15 Sliding guide hole, 16 Sliding groove hole, 17 Sliding groove block, 18 Guide rod, 19 Guide hole, 20 Helical spring, 21 Sliding guide post, 22 Slot block, 23 Slot hole, 24 Positioning pin, 25 Positioning pin hole, 26 Through hole, 27 Threaded hole, 28 Screw. Detailed Implementation

[0026] 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.

[0027] Please see Figure 1-5 An injection molding device for electrofusion pipe fittings includes a lower mold 1, an upper mold 2, a side core 3, and a cover plate 4. The upper mold 2 and the lower mold 1 are fixed together. Several symmetrical mounting grooves 10 are respectively opened on both sides of the upper mold 2 and the lower mold 1. Mounting holes 11 are respectively opened on opposite sides of the mounting grooves 10. Bolts pass through the mounting holes 11 and are threadedly connected to nuts 12. A side core 3 is provided in the central area between the upper mold 2 and the lower mold 1. The two ends of the side core 3 are respectively fixedly connected to the cover plate 4. The cover plate 4 is respectively closed and connected to both sides of the upper mold 2 and the lower mold 1. A mold cavity 5 for injection molding electrofusion pipe fittings is formed between the upper mold 2, the lower mold 1, the side core 3, and the cover plate 4. Two sets of fitting holes 6 are opened on the inner side wall of the mold cavity 5. The fitting holes 6 are all located between the upper mold 2 and the lower mold 1. A cap cylinder 7 is nested in the fitting hole 6. A terminal block 8 is inserted into the cylinder 7, and the other end of the terminal block 8 is connected to the heating wire 9. The heating wire 9 is evenly wound and connected to both sides of the side core 3. In this utility model, the upper mold 2 or the lower mold 1 is provided with an injection hole for the through mold cavity 5. The upper mold 2 and the lower mold 1 adopt a split design, which is convenient for mold opening, part removal and maintenance. After the mold is closed, mechanical fixation (such as bolts) is used to ensure the stability of the injection molding process. The side core 3 is located in the central area between the upper and lower molds 1, and both ends are fixed by the cover plate 4. It is used to form the inner wall structure of the pipe fitting (such as the socket part of the electrofusion interface). The heating wire 9 is evenly wound on both sides of the side core. After being energized, it directly heats the inner wall of the pipe fitting, so that it forms a fusible polymer layer and realizes the electrofusion function. The fitting hole 6 is opened in the inner wall of the mold cavity 5 and is used to fix the cap cylinder 7. The terminal block 8 is connected inside the cap cylinder 7 to prevent the plastic melt from seeping into the cap cylinder 7.

[0028] In the above technical solution, the side core 3 includes a left core 13 and a right core 14, with one end of the left core 13 and the right core 14 being fitted together. A sliding guide hole 15 is provided on the end face of the left core 13, and a sliding groove hole 16 is provided at the bottom of the sliding guide hole 15. A sliding block 17 is slidably connected inside the sliding groove hole 16, and a guide rod 18 is fixedly connected to one side of the sliding block 17. A guide hole 19 is provided on the bottom surface of the sliding groove hole 16, and the guide rod 18 is slidably connected inside the guide hole 19. A helical spring 20 is sleeved on the guide rod 18 inside the sliding groove hole 16, with one end of the helical spring 20 abutting against the bottom surface of the sliding groove hole 16, and the other end of the helical spring 20... One end of the slide block 17 abuts against the slide block 17. The other side of the slide block 17 is fixedly connected to the slide guide post 21. The slide guide post 21 is slidably connected in the slide guide hole 15. The other end of the slide guide post 21 is fixedly connected to the slot block 22. The right core 14 on one side of the slot block 22 has a slot hole 23. The slot block 22 is inserted into the slot hole 23. In use, the left core 13 and the right core 14 are respectively inserted into the two ends of the upper mold 2 and the lower mold 1. During this process, the slide guide post 21 abuts against the right core 14. At the same time, the helical spring 20 is compressed. Through the spring force, the left core 13 and the right core 14 can fit tightly together.

[0029] In the above technical solution, a number of positioning pins 24 are fixedly connected to the right core 14 around the slot hole 23. The sliding guide post 21 on one side of the positioning pin 24 is provided with a positioning pin hole 25. The positioning pins 24 are respectively inserted into the positioning pin hole 25 to achieve precise docking of the left core 13 and the right core 14.

[0030] In the above technical solution, through holes 26 are respectively opened at the four corners of the cover plate 4. Threaded holes 27 are respectively opened on the upper mold 2 and the lower mold 1 on the opposite side of the through holes 26. The screw 28 passes through the through holes 26 and is threaded into the threaded holes 27 to achieve relative fixation of the cover plate 4.

[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 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 embodiments that can be understood by those skilled in the art.

Claims

1. An injection molding apparatus for electrofusion pipe fittings, comprising a lower mold (1), an upper mold (2), a side core (3), and a cover plate (4), characterized in that: The upper mold (2) and the lower mold (1) are closed and fixed together. A side core (3) is provided in the central area between the upper mold (2) and the lower mold (1). The two ends of the side core (3) are respectively fixedly connected to the cover plate (4). The cover plate (4) is closed and connected to both sides of the upper mold (2) and the lower mold (1). An electrical connection for injection molding is formed between the upper mold (2), the lower mold (1), the side core (3) and the cover plate (4). The mold cavity (5) of the melting tube fitting has two sets of fitting holes (6) on its inner side wall. The fitting holes (6) are located between the upper mold (2) and the lower mold (1). A cap tube (7) is nested in the fitting hole (6). A terminal block (8) is inserted into the cap tube (7). The other end of the terminal block (8) is connected to the heating wire (9). The heating wire (9) is evenly wound and connected to both sides of the side core (3).

2. The electrofusion tube injection molding apparatus according to claim 1, characterized in that: The upper mold (2) and the lower mold (1) are provided with several symmetrical mounting grooves (10) on both sides respectively. The mounting grooves (10) are provided with mounting holes (11) on opposite sides respectively. The bolts pass through the mounting holes (11) in sequence and are threadedly connected to the nuts (12).

3. The electrofusion tube fitting injection molding apparatus according to claim 1, characterized in that: The side core (3) includes a left core (13) and a right core (14), with one end of the left core (13) and the right core (14) being fitted together.

4. The electrofusion tube injection molding apparatus according to claim 3, characterized in that: The left core (13) has a sliding guide hole (15) on its end face. A sliding groove hole (16) is formed at the bottom of the sliding guide hole (15). A sliding block (17) is slidably connected inside the sliding groove hole (16). A guide rod (18) is fixedly connected to one side of the sliding block (17). A guide hole (19) is formed on the bottom surface of the sliding groove hole (16). The guide rod (18) is slidably connected inside the guide hole (19). A helical spring (20) is sleeved on the guide rod (18) inside the sliding groove hole (16). One end of the spring (20) abuts against the bottom surface of the slide hole (16), and the other end of the helical spring (20) abuts against the slide block (17). A sliding guide post (21) is fixedly connected to the other side of the slide block (17). The sliding guide post (21) is slidably connected in the slide hole (15). A slot block (22) is fixedly connected to the other end of the sliding guide post (21). A slot hole (23) is opened in the right core (14) on one side of the slot block (22). The slot block (22) is inserted into the slot hole (23).

5. The electrofusion tube injection molding apparatus according to claim 4, characterized in that: A number of positioning pins (24) are fixedly connected to the right core (14) around the slot hole (23). The sliding guide post (21) on one side of the positioning pin (24) is provided with a positioning pin hole (25). The positioning pins (24) are respectively inserted into the positioning pin hole (25).

6. The electrofusion tube fitting injection molding apparatus according to claim 1, characterized in that: The cover plate (4) has through holes (26) at its four corners. The upper mold (2) and lower mold (1) on the opposite side of the through holes (26) have threaded holes (27). The screw (28) passes through the through holes (26) and is threaded into the threaded holes (27).

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