A plastic bag edge folding device and a film blowing machine
By using a symmetrically designed folding mechanism and mechanical linkage, the problem of inconsistent folding depth in existing technologies for plastic bags has been solved, achieving efficient and synchronous folding adjustment and improving the quality and production efficiency of garbage bags.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- GUANGDONG SHUNCHENG ALWAYSEAL TECH
- Filing Date
- 2025-08-08
- Publication Date
- 2026-07-14
AI Technical Summary
Existing plastic bag folding devices are inefficient when adjusting the folding depth and are prone to causing inconsistencies on both sides, affecting the quality of garbage bags.
The folding mechanism, with its symmetrical design, achieves synchronous adjustment on both sides through a single forward and reverse threaded rod and handwheel control. Combined with electric push rods and mechanical linkage, it ensures consistent folding depth, and improves efficiency by driving the winding mechanism with a servo motor.
It significantly improves the quality consistency and production efficiency of plastic bag folding, simplifies the adjustment process, shortens the adjustment time, and improves the continuity of the production line.
Smart Images
Figure CN224490029U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of garbage bag processing equipment, specifically to a plastic bag folding device and a blown film machine. Background Technology
[0002] A blown film machine is the core equipment for producing plastic film, especially tubular plastic film. Its working principle involves heating and melting plastic particles, then extruding them through a ring die to form a film bubble. After inflation and cooling, the bubble is wound into a tubular film by traction rollers and a winding device. This tubular film is the basic material for the subsequent production of various garbage bags. When making garbage bags, the sides of the bag body need to be edged. Edge-feeding involves pressing the sides of the cylindrical film inwards after the plastic bag body is inflated to form a cylindrical film, creating an inward fold. After being pressed by guide components, it becomes a sheet-like film bag with folded edges on both sides. The existing technology has the following problems:
[0003] Chinese patent document CN215590074U discloses a folding device for a plastic bag folding machine, including a mounting frame, a pair of limiting guide frames distributed along the length of the mounting frame to limit and guide the sides of the plastic bag, and a pair of folding plates distributed along the width of the mounting frame to guide the folding side of the plastic bag. The folding plates are located between the two limiting guide frames and are slidably connected to the mounting frame along the width of the mounting frame. The mounting frame is provided with a first adjustment mechanism to adjust the sliding position of the folding plates. This application has the advantage of meeting the needs of folding plastic bags of different sizes.
[0004] Although the folding depth can be adjusted in the aforementioned literature, it can only be adjusted manually by rotating the first and second handwheels. Since it requires adjustment on both sides, the adjustment efficiency is slow, and the alternating adjustment on one side can easily cause inconsistent folding depths on both sides, thus leading to garbage bag quality problems. Utility Model Content
[0005] This invention provides a plastic bag folding device and a blown film machine to solve the problems mentioned in the background art.
[0006] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:
[0007] A plastic bag folding device includes a fixed frame, a first positioning mechanism on the inner side of the fixed frame, a folding mechanism above the first positioning mechanism, a compression mechanism above the folding mechanism, a traction mechanism at the top of the fixed frame, and a winding mechanism below the front end of the fixed frame. The fixed frame includes four vertical columns and four horizontal columns. The first positioning mechanism includes two fixed connecting plates, which are fixedly installed between the front and rear faces of the two vertical columns of the fixed frame. A positive and negative threaded rod is movably installed on the left front of the right fixed connecting plate. The left end of the positive and negative threaded rod 1 extends through to the left side of the left fixed connecting plate and is fixedly installed with a first handwheel. The left and right sides of the outer wall of the positive and negative threaded rod 1 are respectively provided with threaded walls 1 with opposite threads, and the outer walls of the two threaded walls 1 are respectively threaded with first movable plates. The rear ends of the two first movable plates are fixedly installed with clamping frames. The inner rings of the two clamping frames are respectively movably installed between the front and rear sides, and the diameter of the first clamping rotating roller is larger than the width of the clamping frame. The opposite surfaces of the two fixed connecting plates are fixedly installed with a first sliding rod, and the two first movable plates are slidably connected to the first sliding rod.
[0008] A further improvement of this utility model is that: the four horizontal columns are fixedly installed on the top of the four vertical columns, the extrusion mechanism includes an electric push rod and two inclined extrusion plates, the tops of the two inclined extrusion plates are close to each other, and each of the two inclined extrusion plates has several through holes that extend from front to back, and a second clamping rotating roller is movably installed between the left and right sides of the inner circle of the through hole, the diameter of the second clamping rotating roller is greater than the thickness of the inclined extrusion plate.
[0009] A further improvement of this utility model is that: the electric push rod is fixedly installed at the bottom of the left horizontal column, and movable rods are movably installed at the front and back of the right side of the output end of the electric push rod. The two movable rods are movably connected to the upper left side of the two inclined extrusion plates respectively. Mounting plates are movably installed at the bottom of the left and right ends of the two inclined extrusion plates, and the two mounting plates at the front and back are fixedly installed on the opposite sides of the two vertical columns respectively.
[0010] A further improvement of this utility model is that the folding mechanism includes two fixed plates, which are respectively fixedly installed on the top rear side of two fixed connecting plates. A positive and negative threaded rod is movably installed on the left side of the right fixed plate. The left end of the positive and negative threaded rod extends through to the left side of the left fixed plate and is fixedly installed with a second handwheel. The outer walls of the positive and negative threaded rod are respectively provided with threaded walls of opposite threads on the left and right sides. The outer walls of the two threaded walls are respectively threaded with second moving plates. Clamping plates are fixedly installed at the front ends of the two second moving plates. Clamping inclined plates are fixedly installed on the top of the two clamping plates. The top ends of the two clamping inclined plates are inclined and close to each other. The two clamping inclined plates are located between two inclined extrusion plates. Stainless steel U-shaped rods are fixedly installed above the opposite surfaces of the two clamping inclined plates.
[0011] A further improvement of this utility model is that a second sliding rod is fixedly installed between the opposing surfaces of the two fixed plates, and both of the second movable plates are slidably connected to the second sliding rod.
[0012] A further improvement of this utility model is that: the traction mechanism includes two first traction rollers and two second traction rollers, the two first traction rollers are arranged on the top of the fixed frame, and the two second traction rollers are arranged on the front side of the fixed frame; the winding mechanism includes an L-shaped plate, the L-shaped plate is fixedly installed on the front side of the vertical column on the right front side of the fixed frame, a servo motor is fixedly installed on the top of the horizontal part of the L-shaped plate, and the output shaft of the servo motor passes through to the left side of the vertical part of the L-shaped plate and is fixedly installed with a winding roller.
[0013] A blown film machine includes an extrusion blown film mechanism and the aforementioned plastic bag folding device. The extrusion blown film mechanism includes an extruder, the output end of which is fixedly connected to a blown film head. An air inlet pipe is fixedly connected to the left side of the blown film head. An electrically controlled air valve is provided on the outer wall of the air inlet pipe. An air compressor is connected to the input end of the electrically controlled air valve. The folding device is located above the blown film head.
[0014] Due to the adoption of the above technical solution, the technological progress achieved by this utility model compared to the prior art is as follows:
[0015] 1. This utility model provides a plastic bag folding device and a blown film machine. The folding mechanism adopts a symmetrical design and is controlled by a single positive and negative threaded rod and a second handwheel. When the second handwheel is rotated, the opposite threads on both sides of the positive and negative threaded rod drive the two second moving plates to move synchronously in opposite directions along the second slide rod, which drives the clamping inclined plate and the stainless steel U-shaped rod to move towards or separate from the center at the same time. This avoids the problem of depth difference caused by the need to adjust both sides separately in traditional devices. By mechanically linking and forcing symmetrical movement on both sides, it ensures that the folding depth on both sides of the plastic bag is completely consistent, which significantly improves product quality.
[0016] 2. This utility model provides a plastic bag folding device and a blown film machine. By driving the first handwheel with the positive and negative threaded rods, the two first moving plates move synchronously along the first sliding rod, which can quickly adapt to the tubular film of different widths. Moreover, only a single second handwheel needs to be rotated to adjust the folding depth on both sides at the same time, without the need for alternating operation. This simplifies the original step-by-step and alternating adjustment process into a single operation, greatly shortens the adjustment time, and improves the continuity of the production line and the overall efficiency. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the overall structure of this utility model;
[0018] Figure 2 This is a schematic diagram of the first positioning mechanism of the present invention.
[0019] Figure 3 This is a schematic diagram of the extrusion mechanism of the present invention;
[0020] Figure 4 This is a schematic diagram of the folding mechanism of the present invention.
[0021] Figure 5 This is a schematic diagram of the traction mechanism and winding mechanism of this utility model.
[0022] Figure 6 This is a schematic diagram of the extrusion blown film mechanism of this utility model.
[0023] In the diagram: 1. First positioning mechanism; 11. Fixed connecting plate; 12. First threaded rod; 13. First handwheel; 14. First moving plate; 15. Clamping frame; 16. First clamping rotating roller; 17. First sliding rod; 2. Extrusion mechanism; 21. Inclined extrusion plate; 22. Through hole; 23. Second clamping rotating roller; 24. Electric push rod; 25. Movable rod; 26. Mounting plate; 3. Folding mechanism; 31. Fixed plate; 32. First threaded rod 2; 33. Second handwheel; 34. Second slide bar; 35. Second moving plate; 36. Clamping plate; 37. Clamping inclined plate; 38. Stainless steel U-shaped rod; 4. Fixed frame; 5. Extrusion blown film mechanism; 51. Extruder; 52. Blown film head; 53. Air inlet pipe; 54. Electrically controlled air valve; 6. Traction mechanism; 61. First traction roller; 62. Second traction roller; 7. Winding mechanism; 71. L-shaped plate; 72. Servo motor; 73. Winding roller. Detailed Implementation
[0024] To make the technical means, creative features, objectives and effects of this utility model easier to understand
[0025] Understood. The present invention will now be further described in conjunction with specific implementation methods.
[0026] Example 1
[0027] like Figure 1 , Figure 2 As shown, this utility model provides a plastic bag folding device, including a fixed frame 4. A first positioning mechanism 1 is provided on the inner side of the fixed frame 4. A folding mechanism 3 is provided above the first positioning mechanism 1. A squeezing mechanism 2 is provided above the folding mechanism 3. A traction mechanism 6 is provided at the top of the fixed frame 4. A winding mechanism 7 is provided below the front end of the fixed frame 4. The fixed frame 4 includes four vertical columns and four horizontal columns. The first positioning mechanism 1 includes two fixed connecting plates 11. The two fixed connecting plates 11 are fixedly installed between the front and rear vertical columns of the fixed frame 4. A positive and negative threaded rod 12 is movably installed on the left front of the right fixed connecting plate 11. The left end of the positive and negative threaded rod 12 extends through to the left side of the left fixed connecting plate 11 and is fixedly installed with a first handwheel 13. The outer walls of the positive and negative threaded rod 12 are respectively provided with threaded walls with opposite threads on the left and right sides. The outer walls of the two threaded walls are respectively threaded with first moving plates 14. The rear ends of the two first moving plates 14 are fixedly installed with clamping frames 15. The inner rings of the two clamping frames 15 are respectively movably installed between the front and rear sides of the inner rings. The diameter of the first clamping rotating rod 16 is larger than the width of the clamping frame 15. The opposite surfaces of the two fixed connecting plates 11 are fixedly installed with a first sliding rod 17. The two first moving plates 14 are slidably connected to the first sliding rod 17.
[0028] When it is necessary to adjust the left and right position of the blowing cylinder membrane during use, simply rotate the first handwheel 13 to drive the positive and negative threaded rod 12 between the two fixed connecting plates 11 to rotate. By using the threaded wall of the opposite threads on the left and right sides of the outer wall of the positive and negative threaded rod 12 to connect with the threaded connection of the first moving plate 14, the two first moving plates 14 can be driven to move closer together stably and synchronously by sliding connection with the first slide rod 17. This allows the first clamping rotating roller 16 of the inner ring of the two clamping frames 15 to gradually contact the blowing cylindrical membrane, completing the positioning and preventing left and right deviation while adapting to cylindrical membranes of different thicknesses.
[0029] like Figure 3As shown, four horizontal columns are fixedly installed on the top of four vertical columns. The extrusion mechanism 2 includes an electric push rod 24 and two inclined extrusion plates 21. The tops of the two inclined extrusion plates 21 are close to each other. Each of the two inclined extrusion plates 21 has several through holes 22 that pass through from front to back. A second clamping roller 23 is movably installed between the left and right sides of the inner circle of the through hole 22. The diameter of the second clamping roller 23 is larger than the thickness of the inclined extrusion plate 21. The electric push rod 24 is fixedly installed at the bottom of the left horizontal column. Movable rods 25 are movably installed on the right side of the output end of the electric push rod 24. The two movable rods 25 are movably connected to the upper left side of the two inclined extrusion plates 21 respectively. Mounting plates 26 are movably installed at the bottom of the left and right ends of the two inclined extrusion plates 21 respectively. The two mounting plates 26 at the front and back are fixedly installed on the opposite sides of the two vertical columns respectively.
[0030] When it is necessary to flatten the tubular film to form a plastic bag film, simply activate the electric push rod 24 to slowly lower the controller output end. The movable rod 25, connected to the inclined extrusion plate 21, controls the tops of the two inclined extrusion plates 21 to separate from each other until the movable rod 25 remains horizontal. Conversely, when the output end of the electric push rod 24 is pulled upward, the movable rod 25 pulls the tops of the two inclined extrusion plates 21 together, thus synchronously extruding the tubular film. The inclined extrusion plates 21 always rotate on the mounting plate 26. When the two inclined extrusion plates 21 clamp the tubular film from front to back, the second clamping rollers 23 in several through holes 22 improve the smoothness of the contact surface and avoid scratching the film.
[0031] like Figure 4 As shown, the folding mechanism 3 includes two fixed plates 31, which are respectively fixedly installed on the top rear side of two fixed connecting plates 11. A positive and negative threaded rod 32 is movably installed on the left side of the right fixed plate 31. The left end of the positive and negative threaded rod 32 extends through to the left side of the left fixed plate 31 and is fixedly installed with a second handwheel 33. The outer walls of the positive and negative threaded rod 32 are respectively provided with threaded walls of opposite threads on the left and right sides. The outer walls of the two threaded walls are respectively threaded with second moving plates 35. The front ends of the two second moving plates 35 are fixedly installed with clamping plates 36. The tops of the two clamping plates 36 are fixedly installed with clamping inclined plates 37. The tops of the two clamping inclined plates 37 are inclined and close to each other. The two clamping inclined plates 37 are located between two inclined extrusion plates 21. Stainless steel U-shaped rods 38 are fixedly installed above the opposite surfaces of the two clamping inclined plates 37. A second sliding rod 34 is fixedly installed between the opposite surfaces of the two fixed plates 31. The two second moving plates 35 are slidably connected to the second sliding rod 34.
[0032] When the folding depth needs to be adjusted, simply rotate the second handwheel 33 to control the rotation of the two fixed plates 31. The opposite threaded walls on the left and right sides of the outer wall of the two threaded rods 32 are connected to the threaded connection of the second moving plate 35, which drives the two second moving plates 35 to move stably close together through the sliding connection with the second slide rod 34. This drives the two clamping plates 36 and the clamping inclined plate 37 to move closer together between the two inclined extrusion plates 21. Finally, the arc of the opposite ends of the two stainless steel U-shaped rods 38 is used to complete the extrusion folding of both sides of the cylindrical film. The folding depth on both sides can be adjusted at any time by controlling the distance between the two second moving plates 35, improving the adjustment efficiency.
[0033] like Figure 5 As shown, the traction mechanism 6 includes two first traction rollers 61 and two second traction rollers 62. The two first traction rollers 61 are disposed on the top of the fixed frame 4, and the two second traction rollers 62 are disposed on the front side of the fixed frame 4. The winding mechanism 7 includes an L-shaped plate 71. The L-shaped plate 71 is fixedly installed on the front side of the vertical column on the right front side of the fixed frame 4. A servo motor 72 is fixedly installed on the top of the horizontal part of the L-shaped plate 71. The output shaft of the servo motor 72 passes through to the left side of the vertical part of the L-shaped plate 71 and a winding roller 73 is fixedly installed thereon.
[0034] After the film is folded, it can be guided and wound onto the outer wall of the winding roller 73 by the first traction roller 61 and the second traction roller 62. The winding roller 73 can be slowly rotated by the servo motor 72 on the L-shaped plate 71 to continuously complete the winding of the plastic bag after folding.
[0035] Example 2
[0036] Example 2: Figure 6 As shown, this utility model provides a blown film machine, including an extrusion blown film mechanism 5, and also a plastic bag folding device as described in Embodiment 1. The extrusion blown film mechanism 5 includes an extruder 51, the output end of the extruder 51 is fixedly connected to a blown film head 52, the left side of the blown film head 52 is fixedly connected to an air inlet pipe 53, the outer wall of the air inlet pipe 53 is provided with an electrically controlled air valve 54, the input end of the electrically controlled air valve 54 is connected to an air compressor, and the folding device is located above the blown film head 52.
[0037] When the extruder 51 is working, it can melt plastic granules and extrude them through the blown film head 52. High-pressure gas is injected into the blown film head 52 through the air compressor and the electrically controlled air valve 54, thereby blowing the film extruded by the blown film head 52 into a cylindrical shape. The more gas blown out by the blown film head 52, the larger the diameter of the cylindrical film.
[0038] The working principle of the plastic bag folding device and the blown film machine will be explained in detail below.
[0039] like Figure 1-6As shown, when it is necessary to adjust the left and right position of the blowing cylinder membrane during use, simply rotate the first handwheel 13 to drive the positive and negative threaded rod 12 between the two fixed connecting plates 11 to rotate. The threaded walls of the positive and negative threaded rod 12, with their opposite threads on the left and right sides, are threadedly connected to the first moving plate 14. This drives the two first moving plates 14 to move stably and synchronously close together via a sliding connection with the first slide rod 17. This causes the first clamping rotating roller 16 of the inner ring of the two clamping frames 15 to gradually contact the blowing cylindrical membrane, completing the positioning and preventing left and right deviation. It can also accommodate cylindrical membranes of different thicknesses. Furthermore, when it is necessary to clamp the membrane... When flattening and forming the plastic bag film, simply activate the electric push rod 24 to slowly lower the controller output end. The movable rod 25, connected to the inclined extrusion plate 21, controls the separation of the tops of the two inclined extrusion plates 21 until the movable rod 25 remains horizontal. Conversely, pulling the output end of the electric push rod 24 upwards pulls the tops of the two inclined extrusion plates 21 together using the movable rod 25, thus synchronously extruding the film. The inclined extrusion plates 21 always rotate on the mounting plate 26. When the two inclined extrusion plates 21 clamp the film from front to back, the second clamping rollers 23 within several through holes 22 increase the contact surface. To ensure smoothness and avoid scratching the film, when adjusting the folding depth, simply rotate the second handwheel 33 to control the rotation of the two fixed plates 31. This, combined with the threaded connections of the opposite threaded walls on the outer sides of the two threaded rods 32 to the second moving plate 35, drives the two second moving plates 35 to move stably together via a sliding connection with the second slide rod 34. This, in turn, drives the two clamping plates 36 and the clamping inclined plate 37 to move closer together between the two inclined extrusion plates 21. Finally, the curvature of the opposite ends of the two stainless steel U-shaped rods 38 completes the extrusion folding of both sides of the cylindrical film. The folding depth on both sides can be adjusted. The distance between the two second moving plates 35 can be adjusted at any time. After the film is folded, it can be wound up on the outer wall of the winding roller 73 by the guide of the first traction roller 61 and the second traction roller 62. The winding roller 73 can be slowly rotated by the servo motor 72 on the L-shaped plate 71 to continuously complete the winding of the plastic bag after folding. When the extruder 51 is working, it can melt plastic granules and extrude them through the blown film head 52. High pressure gas is injected into the blown film head 52 through the air compressor and the electrically controlled air valve 54, so as to blow the film extruded by the blown film head 52 into a cylindrical shape. The more gas blown out by the blown film head 52, the larger the diameter of the film.
[0040] The present invention has been described in detail above. However, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, any modifications or improvements that do not depart from the spirit of the present invention are within the protection scope of the present invention.
Claims
1. A plastic bag folding device, comprising a fixing frame (4), characterized in that: The fixed frame (4) is provided with a first positioning mechanism (1) on its inner side. A folding mechanism (3) is provided above the first positioning mechanism (1). A pressing mechanism (2) is provided above the folding mechanism (3). A traction mechanism (6) is provided at the top of the fixed frame (4). A winding mechanism (7) is provided below the front end of the fixed frame (4). The fixed frame (4) includes four vertical columns and four horizontal columns. The first positioning mechanism (1) includes two fixed connecting plates (11). The two fixed connecting plates (11) are fixedly installed between the front and rear vertical columns of the fixed frame (4). A positive and negative threaded rod (12) is movably installed on the left front of the right fixed connecting plate (11). The left end of the first handwheel (13) is fixedly installed on the left side of the left fixed connecting plate (11). The outer walls of the first and second threaded rods (12) are respectively provided with threaded walls with opposite threads on the left and right sides. The outer walls of the two threaded walls are respectively threaded with first moving plates (14). The rear ends of the two first moving plates (14) are fixedly installed with clamping frames (15). The inner rings of the two clamping frames (15) are respectively movably installed between the front and rear sides. The diameter of the first clamping rotating rod (16) is larger than the width of the clamping frame (15). The opposite surfaces of the two fixed connecting plates (11) are fixedly installed with first sliding rods (17). The two first moving plates (14) are slidably connected to the first sliding rods (17).
2. The plastic bag folding device according to claim 1, characterized in that: The four horizontal columns are fixedly installed on the top of the four vertical columns. The extrusion mechanism (2) includes an electric push rod (24) and two inclined extrusion plates (21). The tops of the two inclined extrusion plates (21) are close to each other. Both inclined extrusion plates (21) are provided with several through holes (22) that run through the front and back. A second clamping roller (23) is movably installed between the left and right sides of the inner ring of the through hole (22). The diameter of the second clamping roller (23) is greater than the thickness of the inclined extrusion plate (21).
3. A plastic bag folding device according to claim 2, characterized in that: The electric push rod (24) is fixedly installed at the bottom of the left horizontal column. Movable rods (25) are movably installed on the right side of the output end of the electric push rod (24). The two movable rods (25) are movably connected to the upper left side of the two inclined extrusion plates (21). Mounting plates (26) are movably installed at the bottom of the left and right ends of the two inclined extrusion plates (21). The two mounting plates (26) at the front and back are fixedly installed on the opposite sides of the two vertical columns.
4. A plastic bag folding device according to claim 2, characterized in that: The folding mechanism (3) includes two fixing plates (31), which are respectively fixedly installed on the top rear side of two fixed connecting plates (11). A positive and negative threaded rod (32) is movably installed on the left side of the right fixing plate (31). The left end of the positive and negative threaded rod (32) extends through to the left side of the left fixing plate (31) and is fixedly installed with a second handwheel (33). The outer walls of the positive and negative threaded rod (32) are respectively provided with threaded walls with opposite threads on the left and right sides. The outer walls of the two threaded walls are respectively threaded with second moving plates (35). The front ends of the two second moving plates (35) are fixedly installed with clamping plates (36). The tops of the two clamping plates (36) are fixedly installed with clamping inclined plates (37). The tops of the two clamping inclined plates (37) are inclined and close to each other. The two clamping inclined plates (37) are located between the two inclined extrusion plates (21). Stainless steel U-shaped rods (38) are fixedly installed above the opposite surfaces of the two clamping inclined plates (37).
5. A plastic bag folding device according to claim 4, characterized in that: A second slide rod (34) is fixedly installed between the opposite surfaces of the two fixed plates (31), and the two second movable plates (35) are slidably connected to the second slide rod (34).
6. A plastic bag folding device according to claim 1, characterized in that: The traction mechanism (6) includes two first traction rollers (61) and two second traction rollers (62). The two first traction rollers (61) are located on the top of the fixed frame (4), and the two second traction rollers (62) are located on the front side of the fixed frame (4). The winding mechanism (7) includes an L-shaped plate (71). The L-shaped plate (71) is fixedly installed on the front side of the vertical column on the right front side of the fixed frame (4). A servo motor (72) is fixedly installed on the top of the horizontal part of the L-shaped plate (71). The output shaft of the servo motor (72) extends through to the left side of the vertical part of the L-shaped plate (71) and a winding roller (73) is fixedly installed thereon.
7. A blown film machine, comprising an extrusion blown film mechanism (5), characterized in that: It also includes a plastic bag folding device according to any one of claims 1-6, wherein the extrusion blown film mechanism (5) includes an extruder (51), the output end of the extruder (51) is fixedly connected to a blown film head (52), the left side of the blown film head (52) is fixedly connected to an air inlet pipe (53), the outer wall of the air inlet pipe (53) is provided with an electrically controlled air valve (54), the input end of the electrically controlled air valve (54) is connected to an air compressor, and the folding device is located above the blown film head (52).