Multi-point hot runner valve pin injection mechanism for pet plastic chair injection mold

Abstract

The utility model belongs to mould technical field relates to a kind of PET plastic chair injection mould multi-point hot runner valve needle glue feeding mechanism.The utility model, including plastic chair forming upper die, the plastic chair forming upper die bottom is equipped with plastic chair forming surface, the plastic chair forming upper die lower side is equipped with chair body auxiliary forming part and chair leg auxiliary forming part.The utility model in use, multi-point hot runner valve needle glue feeding mechanism is cooperated by glue feeding main hole, glue feeding valve needle and glue feeding hot runner, can be accurately distributed melt according to the different forming needs of chair body and chair leg, avoid the uneven filling problem of single point glue feeding;At the same time, the diameter difference design of glue feeding valve needle and glue feeding main hole, both ensure the smooth flow of melt, and glue feeding switch can be flexibly controlled by the up-down movement of valve needle, eliminate melt leakage, and the shrinkage mark, bubble defect rate of PET plastic chair is reduced.

Description

Technical Field

[0001] This utility model belongs to the field of mold technology and relates to a multi-point hot runner valve needle injection mechanism for PET plastic chair injection mold. Background Technology

[0002] PET plastic chairs are widely used in homes, offices, and outdoors due to their lightweight, high strength, and impact resistance. Their production mainly relies on injection molds; however, existing PET plastic chair injection molds have many technical defects in practical applications, making it difficult to meet the demands of efficient and high-precision production. Specific problems include: 1. Uneven glue injection and poor molding quality: Traditional molds often use a single-point glue injection structure, which... 1. Due to its high viscosity and poor fluidity, single-point injection can easily lead to uneven filling of the melt within the mold cavity (especially in large areas of the chair body and slender structures of the chair legs), resulting in defects such as shrinkage marks, bubbles, and material shortages. Furthermore, the long melt flow path and rapid localized cooling can generate internal stress, causing product deformation. 2. Low precision in the fit between the valve needle and the injection hole: Although some molds use valve needles to control injection, the diameter matching between the valve needle and the injection hole is unreasonable. Either the fit is too tight, causing the valve needle to jam and preventing flexible control of the injection opening and closing; or the fit is too loose, leading to melt leakage, contaminating the mold cavity, and increasing cleaning costs. 3. Auxiliary molding parts are prone to misalignment and low dimensional accuracy: Auxiliary molding parts (inserts, sliders) for the chair body and legs are key components for ensuring the contour forming of the PET plastic chair. However, existing molds lack reliable positioning and limiting structures. Under the action of mold closing and injection pressure, these auxiliary molding parts are prone to lateral displacement, leading to misalignment at the connection between the chair body and the chair legs, resulting in out-of-tolerance product dimensions and a low pass rate. Therefore, there is an urgent need to design a multi-point hot runner valve needle injection mechanism for PET plastic chair injection molds that can overcome the above defects.

[0003] To overcome the shortcomings of existing technologies, people have continuously explored and proposed various solutions. For example, a Chinese patent discloses an interchangeable multi-purpose injection mold for processing plastic chairs [Application No.: 201310162873.8]. This mold includes a fixed mold plate and a moving mold plate. A fixed mold is installed under the fixed mold plate, and a moving mold and guide pillars are installed on the moving mold plate. Fixed blocks are installed on both sides of the moving mold. A cavity is set on the moving mold, and a plastic chair is injection molded between the cavity and the fixed mold. Lifting cylinders are installed on both sides of the cavity, and the piston rods of the lifting cylinders are connected to the fixed blocks. An ejector plate is located in front of the cavity, with an ejector rod installed on one side of the ejector plate and an ejector bracket installed on the other side. An ejector cylinder is installed on the ejector bracket, and the piston rod of the ejector cylinder is connected to the cavity. The ejector rod is driven by the ejector cylinder, and the head of the ejector rod contacts the injection molded plastic chair. However, this solution still easily suffers from uneven glue injection, poor molding quality, low precision in the fit between the valve needle and the glue injection hole, and easy misalignment and low dimensional accuracy of auxiliary molding parts during use. Summary of the Invention

[0004] The purpose of this invention is to address the above-mentioned problems by providing a multi-point hot runner valve needle injection mechanism for PET plastic chair injection molds.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A multi-point hot runner valve needle injection mechanism for a PET plastic chair injection mold includes a plastic chair molding upper mold. The bottom of the plastic chair molding upper mold has a plastic chair molding surface. Below the plastic chair molding upper mold are chair body auxiliary molding parts and chair leg auxiliary molding parts. The chair body auxiliary molding parts and chair leg auxiliary molding parts are respectively positioned and matched with the plastic chair molding surface. A side anti-deviation limiting structure is provided between the chair body auxiliary molding parts and chair leg auxiliary molding parts to fix them. The plastic chair molding upper mold is provided with a multi-point hot runner valve needle injection mechanism, which is positioned corresponding to the plastic chair molding surface.

[0006] In the above-mentioned multi-point hot runner valve needle injection mechanism for PET plastic chair injection mold, the multi-point hot runner valve needle injection mechanism includes a main injection hole disposed in the upper mold of the plastic chair molding, and an injection valve needle is provided at the bottom of the main injection hole, the diameter of the injection valve needle being smaller than the diameter of the main injection hole.

[0007] In the above-mentioned multi-point hot runner valve needle injection mechanism for PET plastic chair injection mold, a hot runner is provided between the injection valve needle and the molding surface of the plastic chair. One side of the hot runner is connected to the bottom of the injection valve needle, and the other side is connected to the molding surface of the plastic chair.

[0008] In the above-mentioned PET plastic chair injection mold multi-point hot runner valve needle injection mechanism, the chair body auxiliary molding part includes a chair body auxiliary molding insert disposed below the upper mold of the plastic chair molding. The top of the chair body auxiliary molding insert is provided with a chair body molding surface, and the shape of the chair body molding surface is adapted to the plastic chair molding surface.

[0009] In the multi-point hot runner valve needle injection mechanism of the above-mentioned PET plastic chair injection mold, the chair body auxiliary molding insert is provided with several parallel connecting rod fixing holes and slots, and the connecting rod fixing holes and slots are equipped with connecting rods for moving the chair body auxiliary molding insert.

[0010] In the above-mentioned PET plastic chair injection mold multi-point hot runner valve needle injection mechanism, the chair leg auxiliary molding part includes two chair leg auxiliary molding sliders disposed below the upper mold of the plastic chair molding. The top of the chair leg auxiliary molding slider is provided with a chair leg molding surface, and the shape of the chair leg molding surface is adapted to the plastic chair molding surface.

[0011] In the above-mentioned multi-point hot runner valve needle injection mechanism of PET plastic chair injection mold, the upper mold of the plastic chair forming has a slider positioning groove, and the chair leg auxiliary forming slider is engaged with the slider positioning groove.

[0012] In the above-mentioned PET plastic chair injection mold multi-point hot runner valve needle injection mechanism, the side anti-deviation limiting structure includes an anti-deviation positioning seat disposed between the chair body auxiliary molding insert and the chair leg auxiliary molding slider. The top of the anti-deviation positioning seat abuts against the chair leg auxiliary molding slider, and the inner side of the anti-deviation positioning seat abuts against the chair body auxiliary molding insert.

[0013] In the above-mentioned multi-point hot runner valve needle injection mechanism of PET plastic chair injection mold, the top of the anti-deviation positioning seat is provided with a T-shaped slide bar, the T-shaped slide bar and the anti-deviation positioning seat are fixed by bolts, the chair leg auxiliary molding slider has a T-shaped slide groove, and the T-shaped slide bar and the T-shaped slide groove slide in a sliding fit.

[0014] In the multi-point hot runner valve needle injection mechanism of the above-mentioned PET plastic chair injection mold, the upper mold of the plastic chair molding has several cooling water channels.

[0015] Compared with existing technologies, the advantages of this utility model are: 1. In use, the multi-point hot runner valve needle injection mechanism of this utility model can accurately distribute melt according to the different molding requirements of the chair body and chair legs through the cooperation of the injection main hole, injection valve needle and injection hot runner, avoiding the problem of uneven filling of single-point injection; at the same time, the diameter difference design between injection valve needle and injection main hole not only ensures smooth melt flow, but also allows flexible control of injection switch by moving the valve needle up and down, eliminating melt leakage and reducing the shrinkage and bubble defect rate of PET plastic chairs.

[0016] 2. The side anti-deviation limiting structure in this utility model achieves bidirectional positioning of the chair body auxiliary molding insert and the chair leg auxiliary molding slider through the cooperation of the anti-deviation positioning seat, T-shaped slide bar and T-shaped slide groove, effectively resisting the lateral deviation caused by injection molding pressure, controlling the product size tolerance and improving the pass rate.

[0017] 3. The connecting rod fixing hole groove of the chair body auxiliary molding insert in this utility model can be quickly moved and adjusted in position by the connecting rod. The chair leg auxiliary molding slider can be quickly disassembled and assembled through the sliding cooperation of the T-shaped slide bar and the T-shaped slide groove. When changing the molding surface of PET plastic chairs of different specifications, there is no need to disassemble the mold as a whole, the adjustment time is shortened, and the mold versatility is significantly improved.

[0018] Other advantages, objectives and features of this invention will be partly apparent from the following description, and partly understood by those skilled in the art through study and practice of this invention. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of this utility model.

[0020] Figure 2 This is a partial structural schematic diagram of the present invention.

[0021] Figure 3 This is a partial structural schematic diagram of another aspect of this utility model.

[0022] Figure 4 This is a partial structural schematic diagram of another aspect of this utility model.

[0023] Figure 5 This is a structural schematic diagram of another aspect of this utility model.

[0024] In the diagram: 1. Upper mold for plastic chair forming; 2. Plastic chair forming surface; 3. Auxiliary forming part for chair body; 4. Auxiliary forming part for chair legs; 5. Side anti-deviation limiting structure; 6. Multi-point hot runner valve needle injection mechanism; 7. Main injection hole; 8. Injection valve needle; 9. Injection hot runner; 10. Auxiliary forming insert for chair body; 11. Chair body forming surface; 12. Connecting rod fixing hole groove; 13. Auxiliary forming slider for chair legs; 14. Slider positioning groove; 15. Anti-deviation positioning seat; 16. T-shaped slide bar; 17. T-shaped slide groove; 18. Cooling water channel; 19. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings.

[0026] like Figure 1-5 As shown, a multi-point hot runner valve needle injection mechanism for a PET plastic chair injection mold includes a plastic chair molding upper mold 1. The bottom of the plastic chair molding upper mold 1 is provided with a plastic chair molding surface 2. A chair body auxiliary molding component 3 and a chair leg auxiliary molding component 4 are provided below the plastic chair molding upper mold 1. The chair body auxiliary molding component 3 and the chair leg auxiliary molding component 4 are respectively positioned and matched with the plastic chair molding surface 2. A side anti-deviation limiting structure 5 for fixing the chair body auxiliary molding component 3 and the chair leg auxiliary molding component 4 is provided between them. A multi-point hot runner valve needle injection mechanism 6 is provided inside the plastic chair molding upper mold 1. The multi-point hot runner valve needle injection mechanism 6 is positioned corresponding to the plastic chair molding surface 2.

[0027] In this embodiment, the bottom of the upper mold 1 for molding the plastic chair is machined to form a plastic chair molding surface 2 that matches the shape of the PET plastic chair. The chair body auxiliary molding part 3 and the chair leg auxiliary molding part 4 are respectively arranged below the upper mold 1 for molding the plastic chair. The top contours of the two correspond one-to-one with the chair body area and the chair leg area of ​​the plastic chair molding surface 2, and their shapes are perfectly matched, together forming the injection cavity of the PET plastic chair. The side anti-deviation limiting structure 5 is fixed to the side connection of the chair body auxiliary molding part 3 and the chair leg auxiliary molding part 4 by bolts to achieve the lateral positioning of the two. The multi-point hot runner valve needle injection mechanism 6 is embedded in the interior of the upper mold 1 for molding the plastic chair, and its injection end corresponds to multiple key filling points of the plastic chair molding surface 2. (Chair body center, chair leg root) Precise alignment, through the shape adaptation of the plastic chair molding surface 2 and auxiliary molding parts 3 and 4, ensures the contour accuracy of the injection cavity; the side anti-deviation limiting structure 5 avoids the misalignment of auxiliary molding parts caused by mold closing and injection pressure; the multi-point injection design of the multi-point hot runner valve needle injection mechanism 6 solves the problem of uneven PET melt filling, and integrates the multi-point hot runner valve needle injection mechanism with the anti-deviation limiting structure of the auxiliary molding parts. In addition, for the "chair body + chair leg" composite structure of PET plastic chair, the injection point corresponds to the key area of ​​the molding surface, breaking the design limitations of the traditional mold "single point injection + rigid fixation", and solving the dual problems of molding quality and positioning accuracy.

[0028] Combination Figure 1-5 As shown, the multi-point hot runner valve needle injection mechanism 6 includes an injection main hole 7 disposed in the upper mold 1 for molding plastic chairs, and an injection valve needle 8 is provided at the bottom of the injection main hole 7. The diameter of the injection valve needle 8 is smaller than the diameter of the injection main hole 7.

[0029] Specifically, the main injection port 7 is a cylindrical channel, with one end connected to the melt output end of the injection molding machine and the other end extending above the plastic molding surface 2. The injection valve needle 8 is a cylindrical metal part (made of H13 hot work die steel with chrome plating), assembled at the bottom of the main injection port 7, and the diameter of the injection valve needle 8 is smaller than that of the main injection port 7, forming an annular melt channel. The top of the injection valve needle 8 is connected to the hydraulic drive device of the mold and can move up and down along the axis of the main injection port 7. The diameter difference between the injection valve needle 8 and the main injection port 7 ensures smooth flow of PET melt in the annular channel and precisely controls the injection switch by the movement of the valve needle (the valve needle moves down to block the channel and stops injection, and moves up to open the channel and start injection). The chrome-plated valve needle has a surface roughness as low as Ra0.02μm, which avoids jamming caused by PET melt adhesion and reduces wear.

[0030] A hot runner channel 9 is provided between the glue inlet valve needle 8 and the plastic chair molding surface 2. One side of the hot runner channel 9 is connected to the bottom of the glue inlet valve needle 8, and the other side is connected to the plastic chair molding surface 2.

[0031] In this embodiment, the hot runner 9 is an arc-shaped metal pipe (made of P20 pre-hardened steel, with a heating wire inside). One end of the pipe is connected to the bottom of the inlet valve needle 8 by welding, and the other end is connected to the inlet of the plastic molding surface 2 by thread. The heating function of the hot runner 9 can keep the temperature of the PET melt stable during the flow process, avoiding the problems of melt cooling and decreased fluidity caused by traditional cold runners. The arc-shaped design of the runner can reduce melt flow resistance, avoid the generation of eddies, and reduce the probability of bubble formation. The direct connection between the hot runner and the molding surface shortens the melt flow path and reduces waste.

[0032] Combination Figure 1-4 As shown, the chair body auxiliary molding component 3 includes a chair body auxiliary molding insert 10 disposed below the upper mold 1 for molding a plastic chair. The top of the chair body auxiliary molding insert 10 is provided with a chair body molding surface 11, and the shape of the chair body molding surface 11 is adapted to the shape of the plastic chair molding surface 2.

[0033] In this embodiment, the chair body forming surface 11 of the chair body auxiliary forming insert 10 is used to assist in forming the chair body surface. The modular design of the chair body auxiliary forming insert 10 makes it easy to replace the chair body forming surface 11 of different specifications (such as PET plastic chairs with different backrest curvatures) without replacing the entire mold. The insert made of pre-hardened steel has strong wear resistance and a long service life. The positioning pin has high positioning accuracy, ensuring the fit between the chair body forming surface 11 and the plastic chair forming surface 2.

[0034] The chair body auxiliary molding insert 10 is provided with a plurality of parallel connecting rod fixing slots 12, and the connecting rod fixing slots 12 are provided with connecting rods for moving the chair body auxiliary molding insert 10.

[0035] In this embodiment, the connecting rod fixing slot 12 is a rectangular channel, with 2-4 slots evenly distributed on the side of the chair body auxiliary molding insert 10, and is formed by milling. The connecting rod is assembled in the connecting rod fixing slot 12, with one end connected to the connecting rod fixing slot 12 by a key, and the other end connected to the servo motor drive device of the mold. The servo motor can drive the connecting rod to move horizontally, thereby driving the chair body auxiliary molding insert 10 to adjust its position. The key connection between the connecting rod and the connecting rod fixing slot 12 ensures the stability of power transmission and prevents the connecting rod from slipping. The servo motor has high driving precision and can accurately adjust the position of the chair body auxiliary molding insert 10 to meet the production needs of PET plastic chairs of different thicknesses. The galvanized connecting rod has strong rust resistance and is suitable for the humid and hot working environment of the mold.

[0036] Combination Figure 3As shown, the chair leg auxiliary forming component 4 includes two chair leg auxiliary forming sliders 13 disposed below the upper mold 1 for forming the plastic chair. The top of the chair leg auxiliary forming sliders 13 is provided with a chair leg forming surface 14, and the shape of the chair leg forming surface 14 is adapted to the shape of the plastic chair forming surface 2.

[0037] In this embodiment, the chair leg forming surface 14 of the chair leg auxiliary forming slider 13 is used to assist in forming the chair leg surface. The symmetrical design of the two chair leg auxiliary forming sliders 13 ensures the forming consistency of the chair legs on both sides of the PET plastic chair. The cooperation between the slider and the guide rail can achieve smooth movement and avoid scratching the product surface during mold opening. The high-precision processing of the chair leg forming surface 14 ensures the surface quality of the chair leg and eliminates the need for subsequent grinding.

[0038] The upper mold 1 for forming the plastic chair has a slider positioning groove 15, and the chair leg auxiliary forming slider 13 is engaged with the slider positioning groove 15.

[0039] In this embodiment, the transition fit between the slider positioning groove 15 and the chair leg auxiliary molding slider 13 achieves precise positioning of the slider and avoids slider displacement during mold closing; the wear-resistant coating can reduce friction and wear between the slider and the groove, and extend service life; the depth design of the groove can ensure the stability of the slider and resist upward displacement caused by injection pressure.

[0040] Combination Figure 1-4 As shown, the side anti-deviation limiting structure 5 includes an anti-deviation positioning seat 16 disposed between the chair body auxiliary forming insert 10 and the chair leg auxiliary forming slider 13. The top of the anti-deviation positioning seat 16 abuts against the chair leg auxiliary forming slider 13, and the inner side of the anti-deviation positioning seat 16 abuts against the chair body auxiliary forming insert 10.

[0041] In this embodiment, the bidirectional abutment design of the anti-deviation positioning seat 16 (top abutment block and inner abutment insert) can simultaneously limit the lateral displacement of the chair leg auxiliary forming slider 13 and the longitudinal displacement of the chair body auxiliary forming insert 10, resulting in high positioning reliability.

[0042] Combination Figure 1-4 As shown, the top of the anti-deviation positioning seat 16 is provided with a T-shaped slide bar 17, and the T-shaped slide bar 17 is fixed to the anti-deviation positioning seat 16 by bolts. The chair leg auxiliary forming slider 13 has a T-shaped slide groove 18, and the T-shaped slide bar 17 and the T-shaped slide groove 18 slide in cooperation.

[0043] In this embodiment, the cooperation between the T-shaped slide bar 17 and the T-shaped groove 18 not only ensures the sliding guidance accuracy of the chair leg auxiliary molding slider 13, but also restricts the vertical displacement of the slider, preventing the slider from detaching from the anti-deviation positioning seat 16; the high-temperature lubricating grease can reduce sliding friction and prevent the PET melt from sticking to the slide bar and groove after leakage; the bolt-fixed T-shaped slide bar 17 is easy to replace, and when the slide bar is worn, there is no need to replace the entire anti-deviation positioning seat 16, reducing maintenance costs.

[0044] Combination Figure 1 As shown, the upper mold 1 for molding the plastic chair has several cooling channels 19.

[0045] In this embodiment, the cooling channels 19 are serpentine channels, numbering 4-6, and are machined inside the upper mold 1 for molding the plastic chair through deep hole drilling. Their distribution path is consistent with the contour of the molding surface 2 of the plastic chair. One end of the cooling channel 19 is connected to the water inlet of the mold (connected to the chiller), and the other end is connected to the water outlet (connected to the return pipe). The chiller can provide circulating coolant at 5-10℃. The serpentine layout of the cooling channels 19 can evenly cover all areas of the molding surface, avoiding insufficient cooling in certain areas. The channel spacing in different areas is optimized (the spacing is smaller in the chair leg area), which can adapt to the different cooling needs of the chair legs (thinner) and the chair body (thicker), ensuring uniform cooling of the entire product. The temperature control of the circulating coolant is precise, which can prevent the PET plastic from generating internal stress due to excessively rapid cooling, or from extending the production cycle due to excessively slow cooling.

[0046] The working principle of this utility model is as follows: During mold closing, the hydraulic system of the mold drives the upper mold 1 of the plastic chair forming to move downward. At the same time, the servo motor drives the chair body auxiliary forming insert 10 to move to the designated position through the connecting rod (assembled in the connecting rod fixing hole slot 12), ensuring that the chair body forming surface 11 is aligned with the plastic chair forming surface 2. The chair leg auxiliary forming slider 13 moves along the guide rail, and its top is embedded in the slider positioning groove 15 of the upper mold 1 of the plastic chair forming. At the same time, the T-shaped sliding groove 18 at the bottom of the chair leg auxiliary forming slider 13 cooperates with the T-shaped sliding strip 17 at the top of the anti-deviation positioning seat 16 to slide until the chair leg forming surface 14 is completely in contact with the chair leg area of ​​the plastic chair forming surface 2. The anti-deviation positioning seat 16 of the side anti-deviation limiting structure 5 abuts against the chair leg auxiliary molding slider 13 at the top and against the chair body auxiliary molding insert 10 on the inner side, thus fixing the two. At this time, the plastic chair molding surface 2, the chair body molding surface 11, and the chair leg molding surface 14 together form a closed PET plastic chair injection molding cavity. The injection molding machine delivers the PET melt heated to 270-290℃ to the main injection hole 7 in the upper mold 1 of the plastic chair molding. The hydraulic drive device drives the injection valve needle 8 to move upward, and the annular channel between the injection valve needle 8 and the main injection hole 7 opens. The PET melt enters the injection hot runner 9 through the annular channel. The heating wire in the hot runner 9 keeps the melt temperature stable. The melt is evenly distributed along the arc-shaped flow channel to multiple injection points (chair center and leg root) on the plastic chair molding surface 2, quickly filling the injection cavity and avoiding local material shortages or air bubbles. When the injection cavity is filled with PET melt, the injection valve needle 8 moves down under hydraulic drive, blocking the connection between the main injection hole 7 and the hot runner 9, stopping the injection. The chiller starts, delivering 5-10℃ coolant to the cooling channel 19 in the upper mold 1 of the plastic chair molding. The coolant flows along the serpentine cooling channel 19, quickly removing the heat from the PET melt in the injection cavity. The differentiated cooling design of the chair body area (slot spacing 15-20mm) and the chair leg area (slot spacing 10-15mm) ensures uniform cooling and crystallization of the melt. The hydraulic system drives the upper mold 1 of the plastic chair molding to move upward, while the chair leg auxiliary molding slider 13 slides outward along the T-shaped slide bar 17, disengaging from the chair leg of the PET plastic chair. The mold ejection device is activated, pushing the chair body auxiliary molding insert 10 upward to eject the PET plastic chair from the injection cavity. The part removal device removes the molded PET plastic chair, and the chair body auxiliary molding insert 10 and the chair leg auxiliary molding slider 13 are reset, ready for the next injection cycle.

[0047] The specific embodiments described herein are merely illustrative examples illustrating the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the spirit of this utility model.

[0048] Although this article frequently uses terms such as 1. upper mold for plastic chair molding, 2. plastic chair molding surface, 3. auxiliary molding part for chair body, 4. auxiliary molding part for chair legs, 5. side anti-deviation limiting structure, 6. multi-point hot runner valve needle injection mechanism, 7. main injection hole, 8. injection valve needle, 9. hot runner injection channel, 10. auxiliary molding insert for chair body, 11. chair body molding surface, 12. connecting rod fixing hole groove, 13. auxiliary molding slider for chair legs, 14. chair leg molding surface, 15. slider positioning groove, 16. anti-deviation positioning seat, 17. T-shaped slide bar, 18. T-shaped slide groove, and 19. cooling water channel, the possibility of using other terms is not excluded. The use of these terms is merely for the convenience of describing and explaining the essence of this utility model; interpreting them as any additional limitation would contradict the spirit of this utility model.

Claims

1. A multi-point hot runner valve needle injection mechanism for a PET plastic chair injection mold, comprising a plastic chair molding upper mold (1), characterized in that, The plastic chair forming upper mold (1) has a plastic chair forming surface (2) at the bottom. The plastic chair forming upper mold (1) has a chair body auxiliary forming part (3) and a chair leg auxiliary forming part (4) below it. The chair body auxiliary forming part (3) and the chair leg auxiliary forming part (4) are respectively positioned and matched with the plastic chair forming surface (2). A side anti-deviation limiting structure (5) for fixing the chair body auxiliary forming part (3) and the chair leg auxiliary forming part (4) is provided between them. A multi-point hot runner valve needle injection mechanism (6) is provided inside the plastic chair forming upper mold (1). The multi-point hot runner valve needle injection mechanism (6) is positioned and matched with the plastic chair forming surface (2).

2. The multi-point hot runner valve needle injection mechanism for PET plastic chair injection molds according to claim 1, characterized in that, The multi-point hot runner valve needle injection mechanism (6) includes an injection main hole (7) disposed in the upper mold (1) of the plastic chair forming, and an injection valve needle (8) is provided at the bottom of the injection main hole (7). The diameter of the injection valve needle (8) is smaller than the diameter of the injection main hole (7).

3. The multi-point hot runner valve needle injection mechanism for PET plastic chair injection molds according to claim 2, characterized in that, A hot runner channel (9) is provided between the glue inlet valve needle (8) and the plastic chair forming surface (2). One side of the hot runner channel (9) is connected to the bottom of the glue inlet valve needle (8), and the other side is connected to the plastic chair forming surface (2).

4. The multi-point hot runner valve needle injection mechanism for PET plastic chair injection molds according to claim 3, characterized in that, The chair body auxiliary molding component (3) includes a chair body auxiliary molding insert (10) disposed below the plastic chair molding upper mold (1). The top of the chair body auxiliary molding insert (10) is provided with a chair body molding surface (11), and the shape of the chair body molding surface (11) matches that of the plastic chair molding surface (2).

5. The multi-point hot runner valve needle injection mechanism for PET plastic chair injection molds according to claim 4, characterized in that, The chair body auxiliary molding insert (10) is provided with a plurality of parallel connecting rod fixing slots (12), and the connecting rod fixing slots (12) are provided with connecting rods for moving the chair body auxiliary molding insert (10).

6. The multi-point hot runner valve needle injection mechanism for PET plastic chair injection molds according to claim 4, characterized in that, The chair leg auxiliary forming part (4) includes two chair leg auxiliary forming sliders (13) disposed below the plastic chair forming upper mold (1). The top of the chair leg auxiliary forming slider (13) is provided with a chair leg forming surface (14), and the shape of the chair leg forming surface (14) matches that of the plastic chair forming surface (2).

7. The multi-point hot runner valve needle injection mechanism for PET plastic chair injection molds according to claim 6, characterized in that, The upper mold (1) for forming the plastic chair has a slider positioning groove (15), and the chair leg auxiliary forming slider (13) is engaged with the slider positioning groove (15).

8. The multi-point hot runner valve needle injection mechanism for PET plastic chair injection molds according to claim 7, characterized in that, The side anti-deviation limiting structure (5) includes an anti-deviation positioning seat (16) disposed between the chair body auxiliary forming insert (10) and the chair leg auxiliary forming slider (13). The top of the anti-deviation positioning seat (16) abuts against the chair leg auxiliary forming slider (13), and the inner side of the anti-deviation positioning seat (16) abuts against the chair body auxiliary forming insert (10).

9. The multi-point hot runner valve needle injection mechanism for PET plastic chair injection molds according to claim 8, characterized in that, The top of the anti-deviation positioning seat (16) is provided with a T-shaped slide bar (17), and the T-shaped slide bar (17) is fixed to the anti-deviation positioning seat (16) by bolts. The chair leg auxiliary forming slider (13) has a T-shaped slide groove (18), and the T-shaped slide bar (17) and the T-shaped slide groove (18) slide in cooperation.

10. The multi-point hot runner valve needle injection mechanism for PET plastic chair injection molds according to claim 1, characterized in that, The upper mold (1) for molding the plastic chair has several cooling channels (19).

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