A plastic film blow molding apparatus

Abstract

The application provides a plastic film blowing device, comprising a film blowing frame and a winding frame for winding the film; the film blowing frame is provided with multiple groups of blowing ports, and one blowing frame is arranged at each group of blowing ports; the rear end of each blowing frame is connected to a shared double-tube channel through a corrugated spring pipe, the lower end of the double-tube channel is connected to a fan body through a fan pipe; the device further comprises a rotary connection assembly, which comprises a shaft groove arranged at the rear end of the double-tube channel, a rotary shaft rotatably arranged in the shaft groove, and a power main rod coaxially penetrating the rotary shaft; the central part of the rotary shaft is fixedly provided with a penetrating cylinder, a plurality of groups of linkage grooves extending in the axial direction are arranged on the circumferential surface of the penetrating cylinder, and the rear end of the double-tube channel is provided with a positioning groove in communication with the linkage grooves. The application solves the problems of the prior art, such as the unadjustable blowing effect of the plastic film blowing device, poor film uniformity and insufficient production flexibility.

Description

Technical Field

[0001] This invention relates to the field of plastic film processing technology, and more specifically, to a plastic film blow molding apparatus. Background Technology

[0002] In traditional plastic film blow molding production, a single blow nozzle or a fixed multi-blow nozzle structure is typically used. This structure often cannot dynamically adjust the airflow distribution and blow angle during the blow molding process, resulting in limitations in thickness uniformity and surface smoothness of the blow-molded film. Especially when producing wide-width or specialty films with high requirements for thickness consistency, traditional equipment struggles to differentiate blow pressure and direction control across different areas, easily leading to problems such as uneven thickness, wrinkles, or inconsistent mechanical properties. Furthermore, existing equipment often requires a complete machine shutdown for adjustments to blow molding parameters, resulting in poor flexibility and impacting production efficiency and product adaptability. Therefore, we have proposed an improved plastic film blow molding device. Summary of the Invention

[0003] The purpose of this invention is to solve the technical problems of existing plastic film blow molding devices, such as the inability to locally adjust the blow molding effect, poor film uniformity, and insufficient production flexibility.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution: A plastic film blow molding apparatus is provided to improve the above-mentioned problems.

[0005] The application is as follows: A plastic film blow molding apparatus includes a film blow molding machine frame and a winding machine frame for winding the film. The inner end of the film blow molding machine frame is provided with multiple blow molding nozzles. The inner end of each blow molding nozzle is wrapped with a set of blow molding frames. The rear end of the blow molding frames is connected to a corrugated spring tube. The tail ends of the multiple sets of corrugated spring tubes are connected to a double pipe channel. The lower end of the double pipe channel is connected to a fan duct. The lower end of the fan duct is connected to a fan body. It also includes a rotating connection assembly, which includes a shaft groove located at the rear end of the dual-tube channel, a rotating shaft, and a power main rod passing through the rotating shaft. A through cylinder and multiple sets of linkage grooves are embedded in the center of the rotating shaft. Each set of linkage grooves has a positioning groove at its outer end. The positioning groove is embedded in the rear end of the dual-tube channel. A central rod is provided in the middle of the through cylinder. Multiple sets of linkage rods are movably provided at the outer end of the central rod. A positioning shaft is provided at the outer end of the linkage rod. A linkage block is provided at the outer end of the positioning shaft.

[0006] As a preferred technical solution of this application, a positioning plate is connected to the outer end of the central rod, a sliding cylinder is provided at the outer end of the positioning plate, a linkage cylinder is provided at the inner end of the sliding cylinder, the positioning plate has a ring of limit holes, a limit rod slides at the inner end of the limit hole, the tail end of the limit rod is fixed on the power main rod, the power main rod passes through the rear end of each set of double pipe channels, the cross section of the power main rod is non-circular, which is used to limit and rotate.

[0007] As a preferred technical solution of this application, the rotating shaft and the power main rod are interlocked. The condition for the rotating shaft to drive the blow molding frame to rotate is that the linkage cylinder extends and drives the linkage block to interlock with the positioning groove, and the linkage cylinder extends and drives the positioning plate to slide along the slide cylinder.

[0008] As a preferred technical solution of this application, the positioning plate is limited in movement by the limiting hole and the limiting rod, the central rod is fixedly connected to the main power rod, and a hinge is provided between the linkage rod and the main power rod, and the linkage rod rotates along the main power rod.

[0009] As a preferred technical solution of this application, the tail end of the linkage rod rotates with the linkage block through the positioning shaft, and the linkage block slides along the through cylinder and moves along the linkage groove and the positioning groove.

[0010] As a preferred technical solution of this application, the lower end of the double-pipe channel is connected to the fan duct, the upper end of the double-pipe channel is movably connected to the corrugated spring tube, the rear end of the corrugated spring tube is provided with an arc-shaped slide, the center of the arc-shaped slide is penetrated by the corrugated spring tube, the outer end of the arc-shaped slide is provided with an arc-shaped groove, the arc-shaped groove is embedded in the outer side of the upper end of the double-pipe channel, and the front end of the corrugated spring tube moves within the blow molding frame.

[0011] As a preferred technical solution of this application, the two ends of the corrugated spring tube are respectively provided with miniature cylinders, which are used to push the blow molding frame to slide along the blow molding port. The blow molding frame slides in and out along the blow molding port to improve the flatness and thickness of the film of a single segment. The miniature cylinders are fixed between the blow molding port and the blow molding frame.

[0012] As a preferred technical solution of this application, each blow molding frame is provided with a sleeve at both ends. The sleeve is sleeved on the outer end of the power main rod, and the two ends of the sleeve are fixed between the blow molding frame and the sub-blow molding frame.

[0013] As a preferred technical solution of this application, the lower end of the blow molding frame is provided with a support structure. The support structure is used to support the blow molding frame when it rotates or moves outward. The support structure includes an arc-shaped groove located at the lower end of the blow molding frame. The inner end of the arc-shaped groove is provided with a movable fixed ball. The lower end of the fixed ball is fixed with a support rod. The outer end of the support rod is provided with a linkage telescopic rod.

[0014] As a preferred technical solution of this application, the linkage telescopic rod is an elastic telescopic rod that can extend and retract according to the movement of the blow molding frame.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: In the scheme of this application: 1. By setting multiple sets of independently adjustable blow molding frames and their driving mechanisms, the blow molding intensity and action angle of local areas of the film can be finely adjusted, which significantly improves the overall thickness uniformity and surface flatness of the film. 2. Through the coordinated action of the rotating connection component and the corrugated spring tube, the blow molding frame can be rotated synchronously as a whole to adjust the angle, and can also be axially displaced independently, thus flexibly adapting to the production needs of different raw materials and different specifications of films. 3. Through the transmission of linkage blocks, linkage grooves, positioning grooves, and non-circular power main rods, the transmission accuracy and structural stability during the adjustment process are ensured. At the same time, the setting of the support structure further ensures the rigid support of the blow molding frame during movement or rotation, improving the long-term reliability of the equipment. Attached Figure Description

[0016] Figure 1 This application provides an overall structural schematic diagram of a plastic film blow molding apparatus. Figure 2 A cross-sectional view of the film blow molding machine frame of a plastic film blow molding apparatus provided in this application; Figure 3 This application provides a plastic film blow molding apparatus. Figure 2 A magnified structural diagram of A in the middle; Figure 4 This application provides a plastic film blow molding apparatus. Figure 2 Top view; Figure 5 A cross-sectional top view of the blow nozzle of a plastic film blow molding apparatus provided in this application; Figure 6 This application provides a plastic film blow molding apparatus. Figure 5 A magnified structural diagram of B in the diagram; Figure 7 A side sectional view of the blow molding frame of a plastic film blow molding apparatus provided in this application; Figure 8 This application provides a plastic film blow molding apparatus. Figure 7 Enlarged structural diagram of the rotating connection component; Figure 9 This application provides a plastic film blow molding apparatus. Figure 7 A magnified structural diagram of C; Figure 10 This application provides a plastic film blow molding apparatus. Figure 7 A magnified structural diagram of D in the diagram; Figure 11 This application provides a plastic film blow molding apparatus. Figure 7 A magnified structural diagram of E in the middle.

[0017] The image shows: 1. Film blow molding machine frame; 2. Rewinding machine frame; 3. Blow molding nozzle; 5. Blow molding frame; 6. Fan duct; 7. Fan body; 8. Dual-pipe channel; 9. Corrugated spring tube; 10. Rotary connecting assembly; 11. Linkage block; 12. Linkage rod; 13. Linkage groove; 14. Positioning shaft; 15. Positioning groove; 16. Central rod; 17. Limiting rod; 18. Linkage cylinder; 19. Shaft groove; 20. Rotating shaft; 21. Support structure; 22. Arc groove; 23. Support rod; 24. Linkage telescopic rod; 25. Fixed ball. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention.

[0019] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate some embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. It should be noted that, unless otherwise specified, the embodiments, features, and technical solutions in the embodiments of the present invention can be combined with each other.

[0020] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0021] like Figures 1-11As shown, this embodiment proposes a plastic film blow molding apparatus, including a film blow molding machine frame 1 and a winding machine frame 2 for winding the film; the film blow molding machine frame 1 is provided with multiple component blow molding nozzles 3, and a blow molding frame 5 is correspondingly provided at each component blow molding nozzle 3; the rear end of each blow molding frame 5 is connected to a common double-pipe channel 8 through a corrugated spring tube 9, and the lower end of the double-pipe channel 8 is connected to the fan body 7 through a fan pipe 6; it also includes a rotating connection assembly 10, which includes a shaft groove 19 provided at the rear end of the double-pipe channel 8, a rotating shaft 20 rotatably provided in the shaft groove 19, and a coaxial through-rotating shaft. The main power rod of shaft 20; a through cylinder is fixedly installed in the center of the rotating shaft 20, and several sets of linkage grooves 13 extending axially are opened in the circumferential direction of the through cylinder. The rear end of the double pipe channel 8 is correspondingly provided with a positioning groove 15 that communicates with the linkage groove 13; a central rod 16 is fixedly installed on the main power rod, and multiple sets of linkage rods 12 are movably hinged to the outer periphery of the central rod 16. The outer end of each set of linkage rods 12 is connected to a linkage block 11 through a positioning shaft 14; the linkage block 11 is slidably installed in the through cylinder and can selectively extend into the linkage groove 13 and the positioning groove 15 to lock or release the rotating shaft 20 and the double pipe channel 8.

[0022] A positioning plate is fixedly connected to the outer end of the central rod 16. The positioning plate is slidably sleeved in a fixedly installed slide cylinder. The slide cylinder is provided with a linkage cylinder 18 for driving the positioning plate to move along its axial direction. The positioning plate has multiple limit holes arranged in a ring. Multiple limit rods 17 corresponding to the limit holes are fixedly installed on the power main rod. The limit rods 17 slide through the corresponding limit holes. The cross-section of the power main rod is non-circular. It passes through the rear end of the double tube channel 8 and slides with it.

[0023] The rotating shaft 20 is circumferentially engaged with the power main rod and can slide relative to it axially. When the linkage cylinder 18 extends and drives the positioning plate and the central rod 16 to move towards the dual-tube channel 8, the linkage block 11 is pushed to be simultaneously engaged in the linkage groove 13 and the positioning groove 15. At this time, the rotating shaft 20 is locked with the dual-tube channel 8, and the rotation of the power main rod can drive the blow molding frame 5 to rotate synchronously through the rotating shaft 20.

[0024] The positioning plate is restricted to moving only along the axial direction of the main power rod by the cooperation of the limiting hole and the limiting rod 17; the central rod 16 is fixedly connected to the main power rod; the linkage rod 12 is movably connected to the main power rod through the hinge and can swing around the hinge point.

[0025] The outer end of the linkage rod 12 is rotatably connected to the linkage block 11 through the positioning shaft 14; when the central rod 16 moves axially, the linkage block 11 is pushed to slide in the through cylinder by the swing of the linkage rod 12, and moves along the linkage groove 13 and the positioning groove 15.

[0026] The lower end of the double-pipe channel 8 is connected to the fan duct 6, and its upper end is movably connected to the rear end of the corrugated spring tube 9. The rear end of the corrugated spring tube 9 is fixedly provided with an arc-shaped sliding piece, the middle of which allows the corrugated spring tube 9 to pass through, and its outer edge is embedded in the arc-shaped groove 22 on the outer side of the upper end of the double-pipe channel 8. The front end of the corrugated spring tube 9 extends movably into the blow molding frame 5.

[0027] Miniature cylinders are provided at both ends of the corrugated spring tube 9. The miniature cylinders are used to push the blow molding frame 5 to slide along the axial direction of the corresponding blow molding port 3 to adjust the flatness and thickness of the film at that position.

[0028] Each blow molding frame 5 is fitted onto the main power rod at both ends via a sleeve, which connects the blow molding frame 5 to the installation structure of the blow molding port 3.

[0029] A support structure 21 is provided below the blow molding frame 5. The support structure 21 includes an arc-shaped guide groove at the bottom of the blow molding frame 5, a fixed ball 25 that is rotatably disposed in the arc-shaped guide groove, a support rod 23 fixed to the lower end of the fixed ball 25, and a linkage telescopic rod 24 that drives the support rod 23 to rise and fall.

[0030] The linkage telescopic rod 24 is an elastic telescopic rod that can extend and retract accordingly as the blow-molded frame 5 moves or rotates to provide adaptive support.

[0031] First, the plastic melt is introduced from the extruder into the die head in the film blow molding machine frame 1. The blower body 7 is started, and the airflow passes through the blower pipe 6, the double pipe channel 8 and the corrugated spring pipe 9 in sequence, and finally blows out from each blow molding frame 5 to blow the plastic preform extruded from the die head into shape. When it is necessary to adjust the thickness or flatness of a specific area of ​​the film, the micro cylinders at both ends of the corresponding corrugated spring tube 9 can be activated; the micro cylinders push the corresponding blow molding frame 5 to slide inward and outward along the axial direction of the blow molding port 3; when the blow molding frame 5 moves inward, the blow molding effect at that point is enhanced, which helps to thin and flatten the film; when it moves outward, the effect is weakened; this adjustment can be performed independently for multiple sets of blow molding frames 5, thereby achieving fine operation of the transverse contour of the film and facilitating the improvement of the film uniformity; If it is necessary to change the overall angle of the blow molding airflow (e.g., to improve the longitudinal stretching of the film or to solve specific wrinkles), the rotating connection assembly 10 is activated, the linkage cylinder 18 extends, and pushes the positioning plate and the central rod 16 to move towards the dual-tube channel 8; the central rod 16 pushes each linkage block 11 outward through the linkage rod 12, so that they simultaneously engage in the linkage groove 13 of the rotating shaft 20 and the positioning groove 15 at the rear end of the dual-tube channel 8, thereby locking the rotating shaft 20 and the dual-tube channel 8; at this time, the drive main rod rotates, and the drive main rod drives all the blow molding frames 5 connected to it to deflect synchronously at a certain angle through the locked rotating shaft 20, thereby changing the overall blow molding direction; after the adjustment is completed, the linkage cylinder 18 retracts, which can pull the linkage block 11 back from the positioning groove 15, so that the blow molding frame 5 returns to its free state or the next round of adjustment can be performed; Throughout the adjustment process, the support structure 21 at the bottom of the blow molding frame 5 always provides adaptive support; the linkage telescopic rod 24 can extend and retract elastically, and its top support rod 23 rolls in the arc-shaped guide groove at the bottom of the blow molding frame 5 through the fixed ball 25, so as to support the blow molding frame 5 without hindering its sliding or rotation, thus ensuring the smoothness and precision of the adjustment action.

[0032] Specifically, when producing high-uniformity optical-grade protective films using this device, especially for high-transparency optical-grade protective films used in displays, the requirements for film thickness consistency (error requirement less than ±3%) and surface imperfections are extremely high. When using this device, the operator first pre-adjusts the axial position of each set of blow molding frames 5 based on the die lip gap and initial bubble shape, ensuring the cooling airflow evenly adheres to the bubble surface. During production, feedback from the online thickness monitoring system indicates that the thickness in the left-hand section of the bubble is slightly excessive. At this point, without stopping the machine, the operator remotely controls the micro-cylinders of the two blow molding frames 5 corresponding to this area, slightly pushing them inward to enhance local cooling intensity, allowing the resin in this area to cool and solidify faster, thus reducing the thickness. Simultaneously, due to slight vibrations at the top of the bubble, the rotating connecting assembly 10 is activated, synchronously adjusting all blow molding frames 5 upwards by a slight angle (e.g., 2°), making the airflow direction more aligned with the upward trajectory of the bubble, instantly stabilizing the bubble shape. Through these dynamic and local adjustments, a high-quality optical film with uniform thickness and a flawless surface is successfully obtained.

[0033] Secondly, when producing wide-width agricultural covering film using this device, especially for films up to 8 meters wide, the central area of ​​the film needs to have high strength, while the two edge areas need to be slightly thinner for easier edge finishing during laying. This device is pre-programmed with an asymmetrical blow molding process. The three sets of blow molding frames 5 in the central area maintain standard positions and angles, providing powerful blow molding to ensure sufficient molecular orientation and high strength in the middle section of the film. The two sets of blow molding frames 5 on each side edge are adjusted to a slightly retracted position using their micro-cylinders, reducing the edge blow molding force and decreasing the film thickness in that area by approximately 10%. Simultaneously, because wide-width film production is prone to edge sagging, the operator rotates the two outermost sets of blow molding frames 5 by a small downward angle (e.g., 3°) through the rotating connecting assembly 10, applying an upward lifting force to the edge of the film bubble, effectively preventing edge sagging and wrinkles. This embodiment demonstrates that the device, through differentiated grouping settings, can produce wide-width special films with longitudinal gradient thickness distribution and good forming stability in a single operation, thus meeting the specific functional requirements of agricultural films.

[0034] Furthermore, this device integrates an intelligent control system during assembly. This closed-loop adjustment system is based on real-time feedback from multiple sensors, and its core function is to ensure high uniformity and high yield in film forming. The system deploys a sensor network in key areas such as film quality, the state of the blow molding frame 5, and the airflow system. Non-contact thickness gauges and vision cameras monitor film thickness and surface defects online. Displacement and angle sensors track the precise position and angle of each blow molding frame 5 in real time, while pressure and flow sensors ensure stable airflow. All data is transmitted to the central controller in real time. The controller also performs instant analysis of the collected data. If a thickness deviation or abnormal shape is detected, it automatically drives the corresponding micro-cylinder or rotating connection component 10 to fine-tune the position of a specific blow molding frame 5 or the overall blow molding angle, thereby accurately correcting forming defects. This enables rapid closed-loop control of the device from monitoring and analysis to execution, significantly improving the first-pass yield and quality stability of film production.

[0035] In the use of this device: During the production start-up phase, after the operator inputs the target film specifications into the central controller, the system enters fully automatic operation; the fan starts to form a stable airflow, and at the same time, the multi-point laser thickness gauge and high-definition vision sensor deployed around the film bubble begin to collect film thickness and surface morphology data in real time; the central controller continuously compares the collected data with the process settings, and once it detects that the thickness of a certain area exceeds the standard or that wrinkles appear, it immediately locks the corresponding blow molding frame 5; the controller then drives the micro cylinder at that location to perform millimeter-level precision displacement, or coordinates the linkage cylinder 18 and the servo motor to perform synchronous angle fine adjustment of the blow molding frame 5. The entire process does not require manual intervention, realizing instantaneous closed-loop correction of molding defects; The entire production process is dynamically coordinated by an intelligent control system that controls all actuators. The system can not only make point-to-point corrections for deviations at single measuring points, but also comprehensively analyze the transverse thickness curve and the overall bubble morphology, making intelligent decisions on whether to adjust the local position, rotate the global angle, or perform a combination of both. During this process, the force sensor under the support structure 21 ensures mechanical stability, the airflow sensor monitors constant pressure, and all subsystem data converges at the controller, forming a collaborative network that ensures molding accuracy. This enables the device to adapt to fluctuations in raw materials and process disturbances, ultimately producing high-quality films with uniform thickness and smooth surfaces, raising the first-time molding pass rate to a new level.

[0036] The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described herein. Although the present invention has been described in detail with reference to the above embodiments, the present invention is not limited to the specific embodiments described above. Therefore, any modifications or equivalent substitutions to the present invention, as well as all technical solutions and improvements that do not depart from the spirit and scope of the invention, are covered within the scope of the claims of the present invention.

Claims

1. A plastic film blow molding apparatus, comprising a film blow molding frame (1) and a winding frame (2) for winding the film, characterized in that: The film blow molding machine frame (1) is provided with a multi-component blow molding port (3), and a blow molding frame (5) is provided at each component blow molding port (3); The rear end of each of the blow-molded frames (5) is connected to a common double-pipe channel (8) via a corrugated spring tube (9), and the lower end of the double-pipe channel (8) is connected to the fan body (7) via a fan pipe (6). It also includes a rotating connection assembly (10), which includes a shaft groove (19) located at the rear end of the dual-tube channel (8), a rotating shaft (20) rotatably located in the shaft groove (19), and a power main rod coaxially passing through the rotating shaft (20). A through-tube is fixedly provided in the center of the rotating shaft (20). Several sets of linkage grooves (13) extending axially are opened in the circumferential direction of the through-tube. A positioning groove (15) connected to the linkage groove (13) is opened at the rear end of the double tube channel (8). A central rod (16) is fixedly installed on the main power rod. Multiple sets of linkage rods (12) are movably hinged to the outer periphery of the central rod (16). The outer end of each set of linkage rods (12) is connected to a linkage block (11) through a positioning shaft (14). The linkage block (11) is slidably installed in the through cylinder and can selectively extend into the linkage groove (13) and the positioning groove (15) to lock or release the rotating shaft (20) and the double tube channel (8). The lower end of the double-pipe channel (8) is connected to the fan pipe (6), and its upper end is movably connected to the rear end of the corrugated spring pipe (9). The rear end of the corrugated spring tube (9) is fixedly provided with an arc-shaped slide plate. The middle part of the arc-shaped slide plate is for the corrugated spring tube (9) to pass through, and its outer edge is embedded in the arc-shaped groove (22) on the outer side of the upper end of the double tube channel (8). The front end of the corrugated spring tube (9) extends movably into the blow molding frame (5). The two ends of the corrugated spring tube (9) are respectively provided with miniature cylinders, which are used to push the blow molding frame (5) to slide along the axial direction of the corresponding blow molding port (3).

2. The plastic film blow molding apparatus according to claim 1, characterized in that: A positioning plate is fixedly connected to the outer end of the central rod (16). The positioning plate is slidably sleeved in a fixedly installed slide cylinder. A linkage cylinder (18) is provided on the slide cylinder for driving the positioning plate to move along its axial direction. The positioning plate has multiple limiting holes arranged in a ring, and the main power rod is fixedly provided with multiple limiting rods (17) that correspond one-to-one with the limiting holes. The limiting rods (17) slide through the corresponding limiting holes. The cross-section of the main power rod is non-circular, and it passes through the rear end of the double-tube channel (8) and slides with it.

3. The plastic film blow molding apparatus according to claim 2, characterized in that: The rotating shaft (20) is circumferentially engaged with the power main rod and can slide relative to it axially; When the linkage cylinder (18) extends and drives the positioning plate and the central rod (16) to move towards the double tube channel (8), the linkage block (11) is pushed to be simultaneously embedded in the linkage groove (13) and the positioning groove (15). At this time, the rotating shaft (20) is locked with the double tube channel (8), and the rotation of the power main rod can drive the blow molding frame (5) to rotate synchronously through the rotating shaft (20).

4. The plastic film blow molding apparatus according to claim 3, characterized in that: The positioning plate is restricted to moving only along the axial direction of the power main rod through the cooperation of the limiting hole and the limiting rod (17); The central rod (16) is fixedly connected to the power main rod; The linkage rod (12) is movably connected to the main power rod through a hinge and can swing around the hinge point.

5. The plastic film blow molding apparatus according to claim 4, characterized in that: The outer end of the linkage rod (12) is rotatably connected to the linkage block (11) through the positioning shaft (14); When the central rod (16) moves axially, the linkage block (11) is pushed to slide inside the through cylinder by the swing of the linkage rod (12), and moves along the linkage groove (13) and the positioning groove (15).

6. The plastic film blow molding apparatus according to claim 5, characterized in that: Each blow molding frame (5) is fitted onto the main power rod at both ends by a sleeve, which connects the blow molding frame (5) to the installation structure of the blow molding port (3).

7. A plastic film blow molding apparatus according to claim 6, characterized in that: A support structure (21) is provided below the blow-molded frame (5). The support structure (21) includes an arc-shaped guide groove at the bottom of the blow-molded frame (5), a fixed ball (25) that is rotatably disposed in the arc-shaped guide groove, a support rod (23) fixed to the lower end of the fixed ball (25), and a linkage telescopic rod (24) that drives the support rod (23) to rise and fall.

8. A plastic film blow molding apparatus according to claim 7, characterized in that: The linkage telescopic rod (24) is an elastic telescopic rod that can extend and retract accordingly as the blow-molded frame (5) moves or rotates, so as to provide adaptive support.

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