Plastic injection molding device for power distribution switch accessories and using method

Abstract

The invention relates to the technical field of plastic injection molding, and discloses a plastic injection molding device for power distribution switch accessories and a using method.The plastic injection molding device comprises an extrusion pipe body and a pushing flat head, the pushing flat head is installed at the end of the extrusion pipe body, a molten plastic injection pipe is installed at the other end of the extrusion pipe body, and a molten plastic flowing cavity is formed in the extrusion pipe body; a pressing piston is slidably arranged in the molten plastic flowing cavity, a plurality of U-shaped material distributing pipes are circumferentially arranged on the outer side wall of the material extruding pipe body, and the two ends of each material distributing pipe communicate with the upper side and the lower side of the pressing piston correspondingly. Due to the fact that the caliber of the outlet of the material pushing flat head is reduced, the impact material pushing operation is achieved, then molten plastic is impacted into the molten plastic originally located in the mold, then the molten plastic is lifted, and the injection molding operation is achieved; in this way, the bubbles are not prone to being clamped between the molten plastic originally located in the mold and the molten plastic newly injected into the mold.

Description

Technical Field

[0001] This invention relates to the field of plastic injection molding technology, and in particular to a plastic injection molding device and method for using power distribution switch accessories. Background Technology

[0002] Power distribution switch components, such as housings and bases, typically require high strength, high flame retardancy, good dimensional stability, and heat resistance. Therefore, the injection molding equipment for these components is not merely a simple shaping tool, but a comprehensive system ensuring key performance indicators. The raw materials for injection molding power distribution switch components generally involve melting and injecting recycled waste plastics, and then re-injecting this recycled molten plastic. However, this injection molding process usually presents the following problems: First, during the injection molding process of waste plastic, it is important to avoid over-melting to prevent gasification during the melting process. This would result in a large number of air bubbles being carried in the molten plastic. If these air bubbles are not removed, they will cause a large number of air bubbles to be present in the injection-molded power distribution switch components, ultimately leading to a problem of low structural strength in the overall power distribution switch components. Secondly, air bubbles are inevitably mixed in during the injection molding process. Therefore, a strong injection pressure needs to be applied to the molten plastic during the injection molding process to expel the air bubbles from the mold. However, conventional injection molding equipment generally uses molten plastic to cover and stack layer by layer. This usually traps a large number of air bubbles between the two layers of molten plastic, which can also lead to a large number of air bubbles in the structure of the power distribution switch accessories, resulting in low strength.

[0003] To address this, we designed a plastic injection molding device and its usage method for power distribution switch accessories. Summary of the Invention

[0004] The purpose of this invention is to solve the problem in the prior art that a large number of air bubbles are trapped between two layers of molten plastic, which also leads to a large number of air bubbles in the structure of power distribution switch accessories and thus low strength. Therefore, this invention proposes a plastic injection molding device and method for power distribution switch accessories.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A plastic injection molding device for power distribution switch accessories includes an extrusion tube body and a pusher head. The pusher head is installed at one end of the extrusion tube body, and a molten plastic injection tube is installed at the other end of the extrusion tube body. The extrusion tube body has a molten plastic flow chamber, and a pressing piston is slidably arranged in the molten plastic flow chamber. Multiple distribution tubes are arranged circumferentially on the outer wall of the extrusion tube body. The distribution tubes are U-shaped and their two ends are respectively connected to the upper and lower sides of the pressing piston. A movable chamber is arranged in the tube wall of the extrusion tube body. A piston ring is slidably arranged in the movable chamber and divides the movable chamber into an upper chamber and a lower chamber. A pressure-sensing heating component is arranged in the lower chamber. The upper chamber is connected to the molten plastic flow chamber through a suction component, and a venting pipe component is arranged on the side wall of the upper chamber. A centrally located propulsion assembly is installed inside the molten plastic flow chamber, and the centrally located propulsion assembly is connected to the pressing piston via a downward pressure rod.

[0006] Preferably, the pressure-sensitive heating component includes: The mounting base and the movable base slide coaxially within the movable cavity. The piston ring is fixed coaxially with the movable base, and a first return spring connects the mounting base and the movable base. An electric heating wire is installed on the inner wall of the molten plastic flow chamber, and a sliding rheostat is installed between the mounting base and the movable base, and a sensor assembly is installed in the lower chamber.

[0007] Preferably, the intake assembly includes: Side tubes are provided in multiples and are inserted circumferentially into the inner wall of the molten plastic flow chamber. The side tubes are connected to the upper chamber. Vertical tubes are arranged in multiples, and are linearly and vertically fixed on the vertical tubes, which are arranged axially along the molten plastic flow chamber.

[0008] Preferably, the vertical pipe has multiple air filter holes on its side wall, and a filter membrane and a second one-way valve are fixed on the air filter holes. The vertical pipe has a cavity, and the airflow direction of the second one-way valve is from the molten plastic flow cavity to the cavity.

[0009] Preferably, a lifting piston and a partition plate are arranged sequentially from top to bottom inside the vertical tube, which are used to divide the tube into an upper chamber, a middle chamber and a lower chamber. The partition plate is fixed to the inner wall of the vertical tube, and the upper chamber and the lower chamber are connected by multiple side connecting holes opened on the inner wall of the vertical tube.

[0010] Preferably, an end sealing plate is fixed to the end of the vertical pipe facing the side pipe, a top rod is coaxially fixed to the lifting piston and slides through the end sealing plate, a second return spring is connected between the lifting piston and the partition plate, an air pressure balance hole communicating with the outside is provided on the middle pipe chamber, a first one-way air valve is provided on the end sealing plate, and the airflow direction of the first one-way air valve is from the upper pipe chamber to the side pipe.

[0011] Preferably, the centrally mounted propulsion assembly includes: The central cylinder is coaxially arranged with the molten plastic flow chamber and connected to the side tube. The side tube is connected to the upper chamber but not to the central cylinder. The rotating rod rotates coaxially with the side tube, and one end of the rotating rod extends into the central cylinder.

[0012] Preferably, the centrally mounted propulsion assembly further includes: The lifting plate and the lower pressure rod are coaxially connected through the top of the central cylinder, and one end of the lower pressure rod extending into the central cylinder is fixed coaxially with the lifting plate. The rotating gear is coaxially fixed with the end of the rotating rod that extends into the central cylinder. The bottom of the lifting plate is provided with multiple downward pressing teeth, which are arranged in a circle. The rotating gear and the downward pressing teeth mesh with each other.

[0013] Preferably, the centrally mounted propulsion assembly further includes: The rotating disk is fixed coaxially with the rotating rod. Multiple rotating disks are installed, each corresponding to a vertical tube and located on the same vertical plane. The outer wall of the rotating disk has multiple grooves, which are curved grooves, and the push rod abuts against the grooves through the second return spring.

[0014] The following are the specific operating steps for using a plastic injection molding device for a power distribution switch accessory: S1: First, the waste plastic is melted and injected into the extrusion tube body through the molten plastic injection pipe. Then, the molten plastic is extruded through the pusher head. Since the outlet of the pusher head is narrowed, it has an impact pushing operation, which then impacts the molten plastic into the molten plastic that was originally located in the mold, thereby raising the molten plastic and realizing the injection molding operation. S2: When the molten plastic is injected into the extrusion tube body from the molten plastic injection tube, it will first impact the pressing piston in the molten plastic flow chamber. Then the pressing piston tends to move towards the pusher head. The molten plastic impacting the pressing piston will flow through the distribution tube to the bottom of the pressing piston. This part of the molten plastic will pass through the electric heating wire for heat preservation or further heating and melting operation, so that the molten plastic reaches the required state and is extruded from the pusher head. S3: When the molten plastic passes through the section where the electric heating wire is located, the heat generated by the electric heating wire will heat the molten plastic passing through the section, causing the molten plastic to heat up further. As the temperature continues to rise during the flow, if the temperature exceeds the predetermined temperature, the molten plastic will boil and generate bubbles. Then these bubbles will come into contact with the vertical pipe in that area. S4: In S2, the molten plastic impacts the pressing piston, causing the pressing piston to drive the lower rod to press down and extend into the central cylinder, maintaining the tendency of the lower rod to extend into the central cylinder. Since the lifting plate at the end of the lower rod has a lower pressing tooth plate, and the rotating rod is driven to rotate through the meshing rotating gear and the lower pressing tooth plate, the rotating rod with the rotation tendency will drive the rotating disk to rotate. Since the top rod abuts against the groove through the second return spring, it will push the top rod down during the rotation of the rotating disk. Due to the presence of the first one-way air valve, if no bubbles are generated, the molten plastic will completely cover the vertical tube. Therefore, during the descent of the lifting piston, the upper tube chamber, the side connecting hole and the lower tube chamber are in a negative pressure state. When the molten plastic is heated to a high temperature and boils to produce bubbles, some of the bubbles are covered by the outer wall of the vertical tube. Therefore, the bubbles will pass through the filter membrane in the filter hole and the second one-way valve and reach the lower tube chamber. This will change the negative pressure in the upper tube chamber, the side connecting hole and the lower tube chamber to the standard atmospheric pressure. At this time, the rotating disk with the rotation tendency will continue to rotate until the push rod is disengaged from the groove. S5: When the rotating disk continues to rotate, the next groove moves above the push rod. At this time, the push rod loses its pushing force. Under the action of the second return spring, the lifting piston rises. Due to the presence of the second one-way air valve, the gas in the upper tube chamber is discharged from the first one-way air valve on the end sealing plate into the side tube. Then this part of the gas will enter the upper chamber. S6: As more gas enters the upper chamber, the vent pipe assembly is closed. The movable base will then be pushed down by the gas, which will shorten the sliding rheostat between the mounting base and the movable base, thereby changing the resistance. Finally, the sensor assembly transmits the change of the sliding rheostat to the heating wire, reducing the heat generated by the heating wire and alleviating the problems caused by the heating wire. At the same time, it can also promptly expel the bubbles generated by the heat, so that the molten plastic discharged does not contain bubbles.

[0015] The beneficial effects of this invention are as follows: 1. In this invention, the heat generated by the electric heating wire heats the molten plastic passing through the zone, further raising the temperature of the molten plastic. As the temperature continues to rise during the flow, if the temperature exceeds the predetermined temperature, the molten plastic will boil and generate bubbles. These bubbles will then come into contact with the vertical pipe in that zone, and some bubbles will be covered by the outer wall of the vertical pipe. Therefore, the bubbles will pass through the filter membrane in the filter hole and the second one-way valve and reach the upper cavity, so that the discharged molten plastic does not contain the bubbles generated by heating. This ensures that the injection-molded power distribution switch accessories are free of bubbles, thereby enhancing the overall strength.

[0016] 2. In this invention, because the outlet of the pusher head is narrowed, it has an impact pusher operation, which then impacts the molten plastic into the molten plastic that was originally located in the mold, thereby raising the molten plastic and realizing the injection molding operation. Compared with the injection molding method of stacking and covering in the prior art, this is less likely to trap air bubbles between the molten plastic that was originally located in the mold and the newly injected molten plastic. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a plastic injection molding device for a power distribution switch accessory proposed in this invention; Figure 2 This is a cross-sectional view of a plastic injection molding device for a power distribution switch accessory proposed in this invention; Figure 3 This is a main sectional view of a plastic injection molding device for a power distribution switch accessory proposed in this invention; Figure 4 This is a schematic diagram of the structure of the central cylinder in the plastic injection molding device for a power distribution switch accessory proposed in this invention; Figure 5 This is a schematic diagram of the side tube structure in a plastic injection molding device for a power distribution switch accessory proposed in this invention; Figure 6 This is a front sectional view of the side tube in a plastic injection molding device for a power distribution switch accessory proposed in this invention; Figure 7 for Figure 6 Enlarged structural diagram at point A; Figure 8 This is a comparison diagram of the injection molding states of traditional injection molding and the injection molding state of this solution.

[0018] In the diagram: 1. Extrusion tube body; 2. Pusher flat head; 3. Molten plastic injection tube; 4. Distributor tube; 5. Molten plastic flow chamber; 6. Pressing piston; 7. Lowering rod; 8. Movable chamber; 9. Mounting base; 10. Movable base; 11. First return spring; 12. Vent pipe assembly; 13. Central cylinder; 14. Side tube; 15. Vertical tube; 16. Filter hole; 17. Piston ring; 18. Lifting plate; 19. Lowering toothed plate; 20. Rotating gear; 21. Rotating rod; 22. Rotating disk; 23. Groove; 24. Lifting piston; 25. Divider plate; 26. Side connecting hole; 27. Second return spring; 28. Air pressure balance hole; 29. ​​Top rod; 30. End sealing plate; 31. First one-way air valve. Detailed Implementation

[0019] Reference Figures 1-8A plastic injection molding device for power distribution switch accessories includes an extrusion tube body 1 and a pusher head 2. The pusher head 2 is installed at one end of the extrusion tube body 1, and a molten plastic injection tube 3 is installed at the other end of the extrusion tube body 1. Therefore, after the waste recycled plastic is washed, cleaned, and dried, it is initially melted and then enters the extrusion tube body 1 through the molten plastic injection tube 3. Then it is pushed out from the pusher head 2 at the other end of the extrusion tube body 1, thereby completing the injection molding operation.

[0020] The extrusion tube body 1 has a movable cavity 8 inside its tube wall. A piston ring 17 is slidably disposed in the movable cavity 8, dividing the movable cavity 8 into an upper cavity and a lower cavity. A pressure-sensitive heating assembly is disposed in the lower cavity. The pressure-sensitive heating assembly includes a mounting base 9 and a movable base 10. The mounting base 9 and the movable base 10 slide coaxially in the movable cavity 8. The piston ring 17 is fixed coaxially with the movable base 10. A first return spring 11 is connected between the mounting base 9 and the movable base 10. An electric heating wire is disposed on the inner wall of the molten plastic flow cavity 5, wherein the electric heating wire is used to heat the molten plastic.

[0021] It should be noted that, referring to Figure 8 The diagrams shown are schematic diagrams of the existing injection molding method and the injection molding method of this device, respectively. In conventional existing technology, the injection molding method adopts a stacking and covering injection method, which is very easy to cause air bubbles to be trapped between the molten plastic originally located in the mold and the newly injected molten plastic during the stacking process. Therefore, this injection molding method of the existing injection molding device is very prone to generating air bubbles. However, in this application, because the outlet of the pusher head 2 has a narrowed diameter, it has an impact push operation, which then impacts the molten plastic into the molten plastic originally located in the mold, thereby raising the molten plastic and realizing the injection molding operation.

[0022] The extrusion tube body 1 has a molten plastic flow chamber 5, and a pressing piston 6 is slidably arranged in the molten plastic flow chamber 5. The outer wall of the extrusion tube body 1 is circumferentially arranged with multiple distribution pipes 4. The distribution pipes 4 are U-shaped and their two ends are respectively connected to the upper and lower sides of the pressing piston 6. When the molten plastic is injected into the extrusion tube body 1 from the molten plastic injection pipe 3, it will first impact the pressing piston 6 in the molten plastic flow chamber 5. Then the pressing piston 6 tends to move towards the pushing flat head 2. The molten plastic impacting the pressing piston 6 will flow through the distribution pipes 4 to the bottom of the pressing piston 6.

[0023] Therefore, this portion of molten plastic will pass through the heating wire for heat preservation or further heating and melting, so that the molten plastic reaches the required state and is then extruded from the pusher head 2.

[0024] The molten plastic impacts the pressing piston 6, causing the pressing piston 6 to drive the lowering rod 7 downwards into the central cylinder 13, maintaining the downward extension of the lowering rod 7 into the central cylinder 13. A central propulsion assembly is provided in the molten plastic flow chamber 5, and the central propulsion assembly is connected to the pressing piston 6 via the lowering rod 7. The central propulsion assembly includes the central cylinder 13, which is coaxially arranged with the molten plastic flow chamber 5 and connected to the side tube 14. The side tube 14 communicates with the upper chamber but is not connected to the central cylinder 13. The central propulsion assembly also includes a lifting plate 18, a downward pressure rod 7 that coaxially passes through the top of the central cylinder 13, and one end of the downward pressure rod 7 that extends into the central cylinder 13 is coaxially fixed with the lifting plate 18. The bottom of the lifting plate 18 is provided with multiple downward pressure tooth plates 19, and the multiple downward pressure tooth plates 19 are arranged in a circle. The rotating gear 20 is coaxially fixed with the end of the rotating rod 21 that extends into the central cylinder 13. The rotating gear 20 and the downward pressure tooth plates 19 mesh with each other. The rotating rod 21 and the side tube 14 coaxially pass through and rotate, and one end of the rotating rod 21 extends into the central cylinder 13.

[0025] Since the lifting plate 18 at the end of the lowering rod 7 has a lowering toothed plate 19, and the rotating rod 21 is driven to rotate by the meshing rotating gear 20 and the lowering toothed plate 19, the rotating rod 21 with the rotation tendency will drive the rotating disk 22 to rotate.

[0026] The suction assembly includes multiple side tubes 14, which are circumferentially inserted into the inner wall of the molten plastic flow chamber 5. The side tubes 14 are connected to the upper chamber. Multiple vertical tubes 15 are linearly and vertically fixed on the vertical tubes 15. The vertical tubes 15 are arranged along the axial direction of the molten plastic flow chamber 5. Multiple air filter holes 16 are opened on the side wall of the vertical tubes 15, and air filter membranes and second one-way air valves are fixed on the air filter holes 16.

[0027] The central propulsion assembly also includes a rotating disk 22, which is coaxially fixed with the rotating rod 21. Multiple rotating disks 22 are provided, and each corresponds to a vertical tube 15 and is located on the same vertical plane. Multiple grooves 23 are provided on the outer side wall of the rotating disk 22. The grooves 23 are curved grooves, and the push rod 29 abuts against the groove 23 through the second return spring 27. Therefore, the push rod 29 will push against the groove 23 and descend during the rotation of the rotating disk 22.

[0028] An end sealing plate 30 is fixed to the end of the vertical pipe 15 facing the side pipe 14. A top rod 29 is coaxially fixed to the lifting piston 24 and slides through the end sealing plate 30. A second return spring 27 is connected between the lifting piston 24 and the partition plate 25. An air pressure balance hole 28 communicating with the outside is provided on the middle pipe chamber. A first one-way air valve 31 is provided on the end sealing plate 30. The airflow direction of the first one-way air valve 31 is from the upper pipe chamber to the side pipe 14. Due to the presence of the first one-way air valve 31, if no bubbles are generated, the molten plastic will completely cover the vertical pipe 15. Therefore, during the descent of the lifting piston 24, the upper pipe chamber, the side communication hole 26 and the lower pipe chamber are in a negative pressure state.

[0029] The vertical tube 15 has a cavity. The airflow direction of the second one-way valve is from the molten plastic flow chamber 5 to the cavity. The vertical tube 15 is provided with a lifting piston 24 and a partition plate 25 from top to bottom, which are used to divide the cavity into an upper chamber, a middle chamber and a lower chamber. The partition plate 25 is fixed to the inner wall of the vertical tube 15. The upper chamber and the lower chamber are connected by multiple side connecting holes 26 opened on the inner wall of the vertical tube 15. When the molten plastic is heated to high temperature and boils to generate bubbles, some bubbles are covered by the outer wall of the vertical tube 15. Therefore, the bubbles will pass through the filter membrane in the filter hole 16 and the second one-way valve and reach the lower chamber. Thus, the negative pressure in the upper chamber, the side connecting hole 26 and the lower chamber will become the standard atmospheric pressure. At this time, the rotating disk 22 with the rotation tendency will continue to rotate until the push rod 29 disengages from the groove 23.

[0030] As the rotating disk 22 continues to rotate, the next groove 23 moves above the push rod 29. At this time, the push rod 29 loses its pushing force. Under the action of the second return spring 27, the lifting piston 24 is lifted upward. Due to the presence of the second one-way air valve, the gas in the upper chamber is discharged from the first one-way air valve 31 on the end sealing plate 30 into the side pipe 14, and then this part of the gas will enter the upper chamber.

[0031] As more gas enters the upper chamber, the vent pipe assembly 12 is closed. The movable base 10 is then pushed down by the gas. A sliding rheostat is installed between the mounting base 9 and the movable base 10, and a sensor assembly is installed in the lower chamber. This shortens the sliding rheostat between the mounting base 9 and the movable base 10, changing its resistance. The sensor assembly transmits this change in the sliding rheostat to the heating wire, reducing the heat generated by the heating wire and alleviating problems caused by its heating. It also allows for the timely removal of air bubbles generated by the heating element, ensuring that the molten plastic discharged is bubble-free. The principle that the change in the resistance of the sliding rheostat causes the sensor assembly to adjust the heating state of the heating wire is existing technology and will not be elaborated upon here.

[0032] The upper cavity is connected to the molten plastic flow cavity 5 through the air suction assembly, and the upper cavity sidewall is provided with a vent pipe assembly 12, wherein the vent pipe assembly 12 includes a vent pipe and an electric valve. When the electric valve is closed, the upper cavity is used to form a sealed space, which facilitates the expansion of the upper cavity space after gas is introduced into the upper cavity. When the pressing piston 6 needs to be reset, simply open the electric valve so that the gas in the upper chamber, under the action of the first reset spring 11, carries the piston ring 17 on the movable base 10 to complete the reset operation. This facilitates the continuous removal of air bubbles generated by the subsequent heating of the molten plastic, ensuring that the injection-molded power distribution switch parts are free of air bubbles and thus enhancing the overall strength.

[0033] The following are the specific operating steps for using a plastic injection molding device for a power distribution switch accessory: S1: First, the waste plastic is melted and injected into the extrusion tube body 1 through the molten plastic injection pipe 3. Then, the molten plastic is extruded through the pusher head 2. Since the outlet of the pusher head 2 is narrowed, it has an impact push operation. Then, the molten plastic is impacted into the molten plastic that was originally located in the mold, thereby raising the molten plastic and realizing the injection molding operation. S2: When the molten plastic is injected into the extrusion tube body 1 from the molten plastic injection pipe 3, it will first impact the pressing piston 6 in the molten plastic flow chamber 5. Then the pressing piston 6 tends to move towards the pusher head 2. The molten plastic impacting the pressing piston 6 will flow through the distribution pipe 4 to the bottom of the pressing piston 6. This part of the molten plastic will pass through the electric heating wire for heat preservation or further heating and melting operation, so that the molten plastic reaches the required state and is extruded from the pusher head 2. S3: When the molten plastic passes through the section where the electric heating wire is located, the heat generated by the electric heating wire will heat the molten plastic passing through the section, causing the molten plastic to heat up further. As the temperature continues to rise during the flow, if the temperature exceeds the predetermined temperature, the molten plastic will boil and generate bubbles. Then these bubbles will come into contact with the vertical pipe 15 in that area. S4: In S2, the molten plastic impacts the pressing piston 6, causing the pressing piston 6 to drive the lowering rod 7 to press down and extend into the central cylinder 13, and maintain the tendency of the lowering rod 7 to extend into the central cylinder 13. Since the lifting plate 18 at the end of the lowering rod 7 has a lowering tooth plate 19, and the rotating rod 21 is driven to rotate by the meshing rotating gear 20 and the lowering tooth plate 19, the rotating rod 21 with the rotation tendency will drive the rotating disk 22 to rotate. Since the top rod 29 abuts against the groove 23 through the second return spring 27, it will push the top rod 29 down during the rotation of the rotating disk 22. Due to the presence of the first one-way air valve 31, if no bubbles are generated, the molten plastic will completely cover the vertical tube 15. Therefore, during the descent of the lifting piston 24, the upper tube chamber, the side connecting hole 26 and the lower tube chamber are in a negative pressure state. When the molten plastic is heated to a high temperature and boils to generate bubbles, some of the bubbles are covered by the outer wall of the vertical tube 15. Therefore, the bubbles will pass through the filter membrane in the filter hole 16 and the second one-way valve and reach the lower tube chamber. This will change the negative pressure in the upper tube chamber, the side connecting hole 26 and the lower tube chamber to standard atmospheric pressure. At this time, the rotating disk 22 with the tendency to rotate will continue to rotate until the top rod 29 is disengaged from the groove 23. S5: When the rotating disk 22 continues to rotate, the next groove 23 moves above the push rod 29. At this time, the push rod 29 loses its pushing force. Under the action of the second return spring 27, the lifting piston 24 is lifted upward. Due to the presence of the second one-way air valve, the gas in the upper tube chamber is discharged from the first one-way air valve 31 on the end sealing plate 30 into the side tube 14. Then this part of the gas will enter the upper chamber. S6: As more gas enters the upper chamber, the vent pipe assembly 12 is in a closed state. The movable base 10 will then be pushed down by the gas, thereby shortening the sliding rheostat between the mounting base 9 and the movable base 10, thus changing the resistance. Finally, the sensor assembly transmits the change of the sliding rheostat to the heating wire, reducing the heat generated by the heating wire and alleviating the problems caused by the heating wire. At the same time, it can also promptly expel the bubbles generated by the heat, so that the molten plastic that is discharged does not contain bubbles.

[0034] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A plastic injection molding device for a power distribution switch accessory, comprising an extrusion tube body (1) and a pusher head (2), wherein the pusher head (2) is installed at one end of the extrusion tube body (1), and a molten plastic injection tube (3) is installed at the other end of the extrusion tube body (1), characterized in that, The extrusion tube body (1) has a molten plastic flow chamber (5) inside, and a pressing piston (6) is slidably arranged inside the molten plastic flow chamber (5). The outer wall of the extrusion tube body (1) is circumferentially arranged with multiple distribution pipes (4). The distribution pipes (4) are U-shaped and their two ends are respectively connected to the upper and lower sides of the pressing piston (6). The tube wall of the extrusion tube body (1) is provided with a movable chamber (8). A piston ring (17) is slidably arranged inside the movable chamber (8) and divides the movable chamber (8) into an upper chamber and a lower chamber. A pressure-sensing heating component is provided in the lower chamber. The upper chamber is connected to the molten plastic flow chamber (5) through an air suction component. A venting pipe component (12) is provided on the side wall of the upper chamber. A central propulsion assembly is provided in the molten plastic flow chamber (5), and the central propulsion assembly is connected to the pressing piston (6) through the pressing rod (7).

2. The plastic injection molding device for a power distribution switch accessory according to claim 1, characterized in that, The pressure-sensitive heating component includes: Mounting base (9) and movable base (10) are both sliding coaxially in movable cavity (8). Piston ring (17) is fixed coaxially with movable base (10). A first return spring (11) is connected between mounting base (9) and movable base (10). An electric heating wire is installed on the inner wall of the molten plastic flow chamber (5), and a sliding rheostat is installed between the mounting base (9) and the movable base (10), and a sensor assembly is installed in the lower chamber.

3. The plastic injection molding device for a power distribution switch accessory according to claim 2, characterized in that, The intake components include: Side tubes (14) are provided in multiple ways and are inserted into the inner wall of the molten plastic flow chamber (5) in a circular pattern. The side tubes (14) are connected to the upper chamber. Vertical tubes (15) are arranged in multiple ways and are linearly and vertically fixed on vertical tubes (15). Vertical tubes (15) are arranged axially along the molten plastic flow chamber (5).

4. The plastic injection molding device for a power distribution switch accessory according to claim 3, characterized in that, The vertical tube (15) has multiple air filter holes (16) on its side wall, and a filter membrane and a second one-way valve are fixed on the air filter holes (16). The vertical tube (15) has a cavity inside, and the airflow direction of the second one-way valve is from the molten plastic flow cavity (5) to the cavity.

5. The plastic injection molding device for a power distribution switch accessory according to claim 4, characterized in that, A lifting piston (24) and a partition plate (25) are arranged sequentially from top to bottom inside the vertical tube (15), which are used to divide the tube into an upper tube chamber, a middle tube chamber and a lower tube chamber. The partition plate (25) is fixed to the inner wall of the vertical tube (15), and the upper tube chamber and the lower tube chamber are connected by multiple side connecting holes (26) opened on the inner wall of the vertical tube (15).

6. The plastic injection molding device for a power distribution switch accessory according to claim 5, characterized in that, An end sealing plate (30) is fixed to the end of the vertical pipe (15) facing the side pipe (14). A top rod (29) is fixed coaxially on the lifting piston (24) and slides through the end sealing plate (30). A second return spring (27) is connected between the lifting piston (24) and the partition plate (25). A pressure balance hole (28) communicating with the outside is provided on the middle pipe chamber. A first one-way air valve (31) is provided on the end sealing plate (30), and the airflow direction of the first one-way air valve (31) is from the upper pipe chamber to the side pipe (14).

7. The plastic injection molding device for a power distribution switch accessory according to claim 6, characterized in that, The mid-mounted propulsion assembly includes: The central tube (13) is coaxially arranged with the molten plastic flow chamber (5) and connected to the side tube (14). The side tube (14) is connected to the upper chamber and is not connected to the central tube (13). Rotating rod (21) rotates coaxially with side tube (14), and one end of rotating rod (21) extends into central tube (13).

8. The plastic injection molding device for a power distribution switch accessory according to claim 7, characterized in that, The mid-mounted propulsion assembly also includes: The lifting plate (18), the lower pressure rod (7) and the top of the central cylinder (13) are coaxially connected and the lower pressure rod (7) extending into the central cylinder (13) is fixed coaxially with the lifting plate (18); Rotating gear (20) is coaxially fixed with the end of rotating rod (21) extending into the central cylinder (13). Multiple pressing tooth plates (19) are provided at the bottom of lifting plate (18), and the multiple pressing tooth plates (19) are arranged in a circle. Rotating gear (20) and pressing tooth plates (19) mesh with each other.

9. The plastic injection molding device for a power distribution switch accessory according to claim 8, characterized in that, The mid-mounted propulsion assembly also includes: Rotating disk (22) is fixed coaxially with rotating rod (21). Multiple rotating disks (22) are provided, and each one corresponds to a vertical tube (15) and is located on the same vertical plane. The outer wall of the rotating disk (22) is provided with multiple grooves (23). The grooves (23) are curved grooves, and the push rod (29) abuts against the grooves (23) through the second return spring (27).

10. A method of using a plastic injection molding device for a power distribution switch accessory, applied to the plastic injection molding device for a power distribution switch accessory as described in claim 9, characterized in that, The specific steps are as follows: S1: First, the waste plastic is melted and injected into the extrusion tube body (1) through the molten plastic injection tube (3). Then the molten plastic is extruded through the pusher head (2) to lift the molten plastic and thus realize the injection molding operation. S2: When the molten plastic is injected into the extrusion tube body (1) from the molten plastic injection tube (3), it will impact the pressing piston (6), and then the pressing piston (6) will tend to move towards the pushing flat head (2). The molten plastic impacting the pressing piston (6) will flow through the distribution tube (4) to the bottom of the pressing piston (6). S3: When the molten plastic passes through the section where the electric heating wire is located, the heat generated by the electric heating wire will heat the molten plastic passing through the section, causing the molten plastic to heat up further and generate bubbles. Then these bubbles will come into contact with the vertical tube (15) in that area. S4: In S2, the molten plastic impacts the pressing piston (6), causing the lowering rod (7) to tend to extend into the central cylinder (13), and driving the rotating rod (21) and rotating disk (22) to rotate. Since the push rod (29) abuts against the groove (23) through the second return spring (27), it will push the push rod (29) down during the rotation of the rotating disk (22), so that the upper tube chamber, the side connecting hole (26) and the lower tube chamber are in a negative pressure state. When the molten plastic is heated to high temperature and boils to generate bubbles, some of the bubbles will be covered by the outer wall of the vertical tube (15). Therefore, the bubbles will reach the lower tube chamber, thereby turning the negative pressure in the upper tube chamber, the side connecting hole (26) and the lower tube chamber into standard atmospheric pressure. At this time, the rotating disk (22) with the tendency to rotate will continue to rotate until the top rod (29) is disengaged from the groove (23). S5: When the rotating disk (22) continues to rotate, the next groove (23) moves above the push rod (29). At this time, the push rod (29) loses its pushing force, and the gas in the upper chamber is discharged from the first one-way valve (31) on the end sealing plate (30) into the side pipe (14). Then this part of the gas will enter the upper chamber. S6: As more gas enters the upper chamber, the vent pipe assembly (12) is closed. The movable base (10) will be pushed down by the gas, thereby shortening the sliding rheostat between the mounting base (9) and the movable base (10), thus changing the resistance. Finally, the sensor assembly transmits the change of the sliding rheostat to the heating wire, reducing the heat generated by the heating wire and alleviating the problem caused by the heating wire. At the same time, it can also promptly discharge the bubbles generated by the heating, so that the molten plastic discharged does not contain bubbles.

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