A longitudinal stretching device and a stretching method for a plastic film

Abstract

The application relates to the technical field of plastic film stretching, and discloses a plastic film longitudinal stretching device which comprises a workbench and further comprises a stretching and winding mechanism installed on one side of the top of the workbench, wherein the stretching and winding mechanism comprises a stretching and winding roller, and the stretching and winding mechanism is used for longitudinally stretching and winding a plastic film; in the application, the stretching and winding roller is driven to synchronously rotate by a synchronous belt and a synchronous pulley, an incomplete gear drives a positioning block to do reciprocating movement along a guide slide rail, and then drives the whole to do reciprocating movement, a second hollow sleeve on a film smoothing mechanism continuously reciprocatingly scrapes the surface of the plastic film in the stretching and winding process; as the side, close to the stretching and winding roller, of the guide block is an arc-shaped structure, when the top pressure yarn moves from right to left, the plastic film, which is stretched and wound at the stretching and winding roller, can be smoothed to the left, the torsion is transmitted backward, the end part of the plastic film after winding is prevented from being uneven, and the film is automatically and continuously tensioned and smoothed.

Description

Technical Field

[0001] This invention relates to the field of plastic film stretching technology, specifically to a plastic film longitudinal stretching device and stretching method. Background Technology

[0002] There are many methods for forming films, such as calendering, casting, blow molding, and stretching. Among them, stretching is a film forming method that has been widely used in recent years. After the polymer raw material is heated and melted by an extruder and extruded into a thick sheet, it is stretched by a certain multiple in the longitudinal and transverse directions under the action of external force in a highly elastic state. This causes the molecular chains or crystal planes to be oriented and arranged in an orderly manner in a direction parallel to the film plane. After cooling and subsequent processing, plastic film products of different thicknesses can be obtained.

[0003] For example, Chinese Patent Publication No. CN118404802A discloses a stretching device for polymer film production. This patent can effectively avoid necking of the film during longitudinal stretching and significantly improve the stretching process, but it does not involve winding twisting and surface dust removal.

[0004] Chinese patent authorization announcement number CN115535691A discloses a winding device for anti-wrinkle biodegradable plastic film. This patent uses incomplete gears to drive reciprocating motion to smooth the film, but it only works on wrinkle problems and requires the cooperation of a motor and an electromagnet, making the structure relatively complex.

[0005] Chinese patent authorization announcement number CN222431597U discloses an automatic film stretching device for high-efficiency rust-proof bags. It uses a dust extraction method to remove dust from the film during the stretching process. However, it requires an external fan and pipeline system, the equipment is large in size, and it cannot solve the problem of uneven winding caused by twisting during the film stretching process.

[0006] Chinese Patent Publication No. CN107758400A discloses an improved film production winding machine. This patent prevents the winding roller from reversing by using a ratchet and pawl to avoid loosening of the film during winding. However, its ratchet mechanism is set on the transmission chain of the winding roller and can only prevent the winding roller itself from reversing. It does not involve the unidirectional rotation control of the guide roller during the stretching process.

[0007] The aforementioned patents propose solutions to individual problems such as necking, wrinkling, dust removal, and anti-reverse twisting during the film stretching process. However, in actual production, the longitudinal stretching device for plastic film still has the following shortcomings: First, uneven tension during film stretching can easily generate torsional force, causing uneven twisting of the film on the film roll, making it impossible to automatically and continuously tension and smooth the film during the stretching process, thus affecting the flatness of the finished film. Second, existing devices cannot automatically remove industrial dust adhering to the film surface before film stretching, and the dust is easy to remain inside the film during the stretching process, affecting the quality of the finished film. Summary of the Invention

[0008] The purpose of this invention is to provide a longitudinal stretching device and method for plastic films, which solves the problems of uneven winding caused by torsional force during the longitudinal stretching process of plastic films in the prior art, and the inconvenience of automatically cleaning industrial dust on the film surface before stretching. The invention achieves automatic relief of torsional force on the plastic film during the stretching process, and drives the film-straightening mechanism to reciprocate during the stretching and winding process to continuously tension and smooth the plastic film, avoiding uneven twisting of the film roll. At the same time, it can automatically remove industrial dust attached to the film surface before stretching, thereby improving the stretching flatness and quality of the finished film.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a plastic film longitudinal stretching device, comprising a worktable, and further comprising: A stretching and winding mechanism is installed on one side of the top of the workbench. The stretching and winding mechanism includes a stretching roller and is used to stretch and wind a plastic film longitudinally. A guiding film mechanism is installed on the top of the worktable and symmetrically distributed on both sides away from the stretching and winding film mechanism. The guiding film mechanism includes an upper guiding roller and a lower guiding roller. The guiding film mechanism is used for longitudinal guidance of the plastic film and to relieve torque. A reciprocating drive mechanism is symmetrically distributed on both sides of the worktable. The reciprocating drive mechanism includes a positioning block and is used to drive reciprocating motion. A film-stretching mechanism is installed between the two sets of reciprocating drive mechanisms. The film-stretching mechanism includes a fixing plate and is used to tension the plastic film. A dust removal mechanism is installed between the two sets of the guide film mechanism. The dust removal mechanism includes a dust removal adsorption plate and is used to adsorb and remove industrial dust from the surface of the plastic film.

[0010] Furthermore, an outer protective net is fixedly installed in the middle of the periphery of the workbench, and the stretching film winding mechanism also includes a bearing seat fixedly installed at the end of the periphery of the workbench. The stretching roller is rotatably installed between two sets of bearing seats. A servo motor is fixedly installed on the bearing seat located at one end of the front of the workbench, and the output end of the servo motor is fixedly connected to the end shaft of the stretching roller.

[0011] Furthermore, the guiding film mechanism also includes a fixed seat fixedly installed on the top of the workbench away from the stretching and rolling film mechanism, the dust removal and adsorption plate fixedly installed on the side of the fixed seat away from the reciprocating drive mechanism, a linear slide rail fixedly installed on one side of the inner wall of the fixed seat, a cylinder fixedly installed on the top of the fixed seat, a slider slidably connected to the outside of the linear slide rail, the two ends of the upper guide roller are respectively rotatably installed between the two sets of sliders, the lower guide roller is rotatably installed on the inner wall of the fixed seat near the bottom, and the upper guide roller and the lower guide roller are in parallel clearance fit, and the telescopic end of the cylinder is fixedly connected to the top of the corresponding slider on the same side.

[0012] Furthermore, one-way ratchet wheels are fixedly sleeved on the rotating shafts at both ends of the lower guide roller, and connecting seats are fixedly installed on the inner walls of the two sets of fixed seats near the bottom. Pads are rotatably installed on the outer side of the connecting seats via rotating shafts. A first torsion spring is fixedly installed between the pawl and the connecting seat. The pawl meshes with the one-way ratchet wheel on the same side. Side connecting plates are fixedly installed on the outer rotating shaft ends of the two sets of pawls. A first connecting roller is fixedly installed in the U-shaped groove at the end of the two sets of side connecting plates away from the pawls, and a first hollow sleeve is movably sleeved on the outside of the first connecting roller.

[0013] Furthermore, the reciprocating drive mechanism includes two sets of side seats fixedly installed at the top edge of the worktable. Guide slide rails are fixedly installed on the inner sides of the two sets of side seats respectively. Positioning blocks are slidably connected inside the guide slide rails. Positioning racks are integrally formed on the top and bottom of the inner wall of the positioning blocks respectively.

[0014] Furthermore, the inner sides of the two sets of side seats are respectively rotatably mounted with incomplete gears via rotating shafts. The incomplete gears are located in the inner wall of the positioning block and mesh with the positioning rack.

[0015] Furthermore, positioning seats are fixedly installed on the inner sides of the two sets of guide rails respectively, and a connecting rod is rotatably installed between the two sets of positioning seats. The fixing plate is fixedly installed on the middle of the periphery of the connecting rod, and a second torsion spring is fixedly installed between the two ends of the connecting rod and the corresponding positioning seat.

[0016] Furthermore, a second connecting roller is fixedly installed on the U-shaped groove on the side of the fixed plate away from the connecting rod, and a second hollow sleeve is movably sleeved on the outside of the second connecting roller. Top pressure rollers are fixedly installed at both ends of the second connecting roller in the U-shaped groove on the side of the fixed plate away from the connecting rod, and a guide block is provided on the top of the top pressure roller. A connecting frame is fixedly installed between the guide block and the inner wall of the side seat.

[0017] Furthermore, synchronous belts are fixedly sleeved on the stretching roller, the one-way ratchet, and the outer shaft of the incomplete gear located on the same side, and synchronous pulleys are fixedly sleeved on the outside of the three sets of synchronous belts located on the same side.

[0018] The present invention also provides a stretching method for the above-mentioned longitudinal stretching device for plastic film, comprising the following steps: S1. Film insertion and fixing: Insert the end of the plastic film to be stretched between the two sets of fixing seats, pass through the inside of the dust removal and adsorption plate, then pass between the upper guide roller and the lower guide roller, and finally fix the end of the film to the outside of the stretching roller. S2. Clamping and positioning: Start the cylinder, and the cylinder will drive the slider to move down along the linear slide rail, so that the upper guide roller moves down and cooperates with the lower guide roller to clamp the plastic film, thus completing the pre-stretching positioning. S3. Stretch and wind: Start the servo motor, which drives the stretching roller to rotate at a constant speed to continuously stretch and wind the plastic film longitudinally. S4. Dust removal: During the process of the slider moving down and clamping, the pawl moves down and moves the one-way ratchet to rotate, which drives the lower guide roller to rotate and drives the side connecting plate to swing back and forth. The first hollow sleeve shakes the film to make the surface dust fall off and be adsorbed by the dust removal adsorption plate. S5. Reciprocating film winding: During the stretching and winding process, the stretching roller drives the incomplete gear to rotate via synchronous transmission. The incomplete gear drives the positioning block and the film winding mechanism to reciprocate. The second hollow sleeve continuously reciprocates to flatten and tension the film surface, relieving torsional torque, until the longitudinal stretching process of the entire plastic film is completed.

[0019] This invention uses a single servo motor to drive the stretching roll, which simultaneously drives the incomplete gear and the one-way ratchet to operate synchronously through a synchronous belt and synchronous pulley. One power source synchronously realizes three functions: stretching and winding, reciprocating film winding, and dust removal. No additional drive motor is required, which greatly simplifies the equipment structure, reduces manufacturing costs, and ensures that the actions of each mechanism are precisely matched with the winding speed, resulting in stronger synchronization.

[0020] In this invention, the incomplete gear and the rack of the frame-shaped positioning block alternately mesh, driving the film-straightening mechanism to reciprocate linearly along the film-feeding direction. The second hollow sleeve continuously smooths the film surface. At the same time, in conjunction with the arc-shaped guide surface of the guide block and the elastic force of the second torsion spring, the top pressure wheel drives the fixed plate to make a small reciprocating swing, further enhancing the tensioning and smoothing effect. The torsional torque generated by film stretching is continuously transmitted to the feeding side, avoiding the accumulation of torque at the winding end and causing uneven end faces, thus significantly improving the winding flatness.

[0021] The lower guide roller of this invention achieves unidirectional rotation through the cooperation of a unidirectional ratchet and a pawl, allowing the film to move only along the stretching direction, effectively preventing the film from shrinking back after stretching, ensuring the stability of the longitudinal stretching ratio, and improving the consistency of the mechanical properties of the finished film.

[0022] The rotation of a one-way ratchet drives the pawl to periodically swing, causing the first hollow sleeve to tap the film surface at high frequency, shaking off the stubborn dust particles. These particles are then collected by the dust collection plates on both sides. The dust collection action is fully linked to the stretching process, eliminating the need for external fans and piping systems. The equipment is small in size and highly integrated, effectively preventing dust from being pressed into the film during stretching and improving the appearance quality of the finished film.

[0023] This invention uses a cylinder to drive a slider to rise and fall along a linear slide rail, which can flexibly adjust the gap between the upper and lower guide rollers to meet the processing needs of plastic films of different thicknesses. The clamping process is stable and reliable, and can prevent the film from deviating and wrinkling. Attached Figure Description

[0024] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a schematic diagram of the reciprocating drive mechanism and the dust removal mechanism in this invention; Figure 3 This is a schematic diagram of the side cross-sectional structure of the workbench in this invention; Figure 4 This is a schematic diagram of the reciprocating drive mechanism and the film-smoothing mechanism in this invention; Figure 5 This is a schematic diagram of the guiding membrane mechanism in this invention; Figure 6 for Figure 4 A magnified view of the structure at point A in the middle; Figure 7 for Figure 5 A magnified schematic diagram of the structure at point B in the middle.

[0025] In the diagram: 100, worktable; 200, stretching film winding mechanism; 300, guiding film mechanism; 400, reciprocating drive mechanism; 500, film smoothing mechanism; 600, dust removal mechanism; 11, outer protective net; 21, stretching roll; 22, bearing seat; 23, servo motor; 24, synchronous belt; 25, synchronous pulley; 31, fixed seat; 32, upper guide roller; 33, lower guide roller; 34, one-way ratchet; 35, pawl; 36, side connecting plate; 37, ... 311. Hollow sleeve; 312. Linear slide rail; 313. Cylinder; 314. Slider; 351. Connecting seat; 352. First torsion spring; 41. Side seat; 42. Guide slide rail; 43. Positioning block; 44. Incomplete gear; 431. Positioning rack; 51. Connecting rod; 52. Fixing plate; 53. Positioning seat; 54. Second torsion spring; 55. Second hollow sleeve; 56. Guide block; 551. Top pressure roller; 561. Connecting frame; 61. Dust collection and adsorption plate. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. The described embodiments are only some embodiments of the present invention, and not all embodiments. Example

[0027] This embodiment provides a longitudinal stretching device for plastic film, such as... Figures 1 to 7 As shown, it includes a worktable 100, as well as a stretching and winding film mechanism 200, a guiding film mechanism 300, a reciprocating drive mechanism 400, a film rolling mechanism 500, and a dust removal mechanism 600.

[0028] A film stretching and winding mechanism 200 is mounted on one side of the top of the worktable 100 and includes a stretching and winding roller 21 for longitudinally stretching and winding the plastic film. A film guiding mechanism 300 is mounted symmetrically on both sides of the top of the worktable 100 away from the film stretching and winding mechanism 200, and includes an upper guide roller 32 and a lower guide roller 33 for longitudinally guiding the plastic film and relieving torque. A reciprocating drive mechanism 400 is mounted symmetrically on both sides of the worktable 100 and includes a positioning block 43 for driving reciprocating motion.

[0029] Specifically, an outer protective net 11 is fixedly installed in the center of the periphery of the workbench 100 for safety protection. The stretching film winding mechanism 200 also includes a bearing seat 22 fixedly installed at the periphery of the workbench 100, and the stretching roller 21 is rotatably installed between the two sets of bearing seats 22. A servo motor 23 is fixedly installed on the bearing seat 22 located at one end of the front of the workbench 100, and the output end of the servo motor 23 is fixedly connected to the end shaft of the stretching roller 21. During operation, the plastic film passes through the upper guide roller 32 and the lower guide roller 33 of the guide film mechanism 300 from one side of the workbench 100, and is then longitudinally stretched and wound up by the stretching roller 21 of the stretching film winding mechanism 200. When the servo motor 23 drives the stretching roller 21 to rotate, the stretching roller 21 drives the incomplete gear 44 to rotate synchronously through the synchronous belt 24 and the synchronous pulley 25.

[0030] The guiding film mechanism 300 also includes a fixed base 31 fixedly installed on the top of the worktable 100 away from the stretching film winding mechanism 200. A dust removal and adsorption plate 61 is fixedly installed on the side of the fixed base 31 away from the reciprocating drive mechanism 400. A linear slide rail 311 is fixedly installed on one side of the inner wall of the fixed base 31, and a cylinder 312 is fixedly installed on the top of the fixed base 31. A slider 313 is slidably connected to the outside of the linear slide rail 311, and the two ends of the upper guide roller 32 are rotatably installed between the two sets of sliders 313. The lower guide roller 33 is rotatably installed on the inner wall of the fixed base 31 near the bottom, and the upper guide roller 32 and the lower guide roller 33 are in a parallel clearance fit. The telescopic end of the cylinder 312 is fixedly connected to the top of the corresponding slider 313 on the same side. By driving the slider 313 up and down along the linear slide rail 311 with the cylinder 312, the gap between the upper guide roller 32 and the lower guide roller 33 can be flexibly adjusted to adapt to plastic films of different thicknesses, ensuring stable tension during the guiding process and preventing wrinkles or deviations during film stretching.

[0031] One-way ratchet wheels 34 are fixedly fitted onto the rotating shafts at both ends of the lower guide roller 33. Connecting seats 351 are fixedly installed on the inner walls of the two sets of fixed seats 31 near the bottom. Pads 35 are rotatably mounted on the outer side of the connecting seats 351 via rotating shafts. A first torsion spring 352 is fixedly installed between the pawl 35 and the connecting seat 351, and the pawl 35 meshes with the corresponding one-way ratchet wheel 34 on the same side. Side connecting plates 36 are fixedly installed at the outer ends of the rotating shafts of the two sets of pawls 35. A first connecting roller is fixedly installed in the U-shaped groove at the end of the two sets of side connecting plates 36 away from the pawl 35, and a first hollow sleeve 37 is movably fitted onto the outside of the first connecting roller. When the stretching roller 21 is driven by the synchronous belt 24 and the synchronous pulley 25, the one-way ratchet wheel 34 rotates unidirectionally via the outer synchronous pulley 25 and the synchronous belt 24, ensuring that the plastic film passing through the lower guide roller 33 can only rotate in the stretching direction during stretching, preventing reverse rotation from causing longitudinal stretching and shrinkage of the plastic film.

[0032] The reciprocating drive mechanism 400 includes two sets of side seats 41 fixedly installed at the top edge of the worktable 100. Guide rails 42 are fixedly installed on the inner surfaces of the two sets of side seats 41, and positioning blocks 43 are slidably connected inside the guide rails 42. Positioning racks 431 are integrally formed on the top and bottom of the inner wall of the positioning blocks 43. Incomplete gears 44 are rotatably installed on the middle portions of the inner surfaces of the two sets of side seats 41 via rotating shafts. The incomplete gears 44 are located in the inner wall of the positioning blocks 43 and mesh with the positioning racks 431. When the stretching roller 21 drives the incomplete gears 44 to rotate synchronously via the synchronous belt 24 and synchronous pulley 25, the incomplete gears 44 alternately mesh with the positioning racks 431 at the top and bottom of the inner wall of the positioning blocks 43 during rotation, driving the positioning blocks 43 to reciprocate linearly along the guide rails 42, thereby driving the entire film-rolling mechanism 500 to reciprocate.

[0033] In this embodiment, during operation, the plastic film passes through the upper guide roller 32 and lower guide roller 33 of the guiding film mechanism 300 from one side of the worktable 100, and is then longitudinally stretched and wound up by the stretching roller 21 of the stretching and winding mechanism 200. When the servo motor 23 drives the stretching roller 21 to rotate, the stretching roller 21 drives the incomplete gear 44 to rotate synchronously through the synchronous belt 24 and the synchronous pulley 25. The incomplete gear 44 alternately meshes with the positioning racks 431 at the top and bottom of the inner wall of the positioning block 43, driving the positioning block 43 to reciprocate linearly along the guide slide rail 42, thereby driving the entire film-straightening mechanism 500 to reciprocate. The second hollow sleeve 55 on the film-straightening mechanism 500 continuously scrapes the surface of the plastic film during the stretching and winding process. Because the guide block 56 has an arc-shaped structure near the stretching roller 21, when the top pressure roller 551 moves from right to left, it can smooth the plastic film wound at the stretching roller 21 to the left, transmitting torque backward to prevent unevenness at the film end after winding, thus achieving automatic and continuous tensioning and smoothing. At the same time, the top pressure roller 551 rolls back and forth along the bottom slope of the guide block 56, which, together with the second torsion spring 54, drives the connecting rod 51 and the fixing plate 52 to make small back-and-forth swings, further enhancing the film tensioning effect and effectively alleviating the torsional torque caused by uneven tension during the stretching process. Example

[0034] Based on Example 1, this embodiment further provides specific structures for the film-rolling mechanism 500 and the dust removal mechanism 600, as described above. Figures 3 to 7 As shown.

[0035] A film tensioning mechanism 500 is installed between two sets of reciprocating drive mechanisms 400 and includes a fixing plate 52 for tensioning the plastic film. A dust removal mechanism 600 is installed between two sets of guiding film mechanisms 300 and includes a dust removal adsorption plate 61 for adsorbing and removing industrial dust from the surface of the plastic film.

[0036] Positioning seats 53 are fixedly installed on the inner sides of two sets of guide rails 42, and a connecting rod 51 is rotatably installed between the two sets of positioning seats 53. A fixing plate 52 is fixedly installed on the outer center of the connecting rod 51. A second torsion spring 54 is fixedly installed between the two ends of the connecting rod 51 and the corresponding positioning seat 53. A second connecting roller is fixedly installed on the U-shaped groove on the side of the fixing plate 52 away from the connecting rod 51, and a second hollow sleeve 55 is movably sleeved on the outside of the second connecting roller. In the U-shaped groove on the side of the fixing plate 52 away from the connecting rod 51, a top pressure roller 551 is fixedly installed at both ends of the second connecting roller. A guide block 56 is provided on the top of the top pressure roller 551, and a connecting frame 561 is fixedly installed between the guide block 56 and the inner wall of the side seat 41. The second hollow sleeve 55 on the film-straightening mechanism 500 continuously scrapes the surface of the plastic film during the stretching and winding process. In conjunction with the arc-shaped structure of the guide block 56 near the stretching roller 21, the top pressure roller 551 moves from right to left, which straightens the wound plastic film to the left and transmits the torque backward to avoid unevenness at the end of the film after winding.

[0037] Synchronous belts 24 are fixedly fitted onto the outer shafts of the stretching roller 21, the one-way ratchet 34, and the incomplete gear 44, all located on the same side. Synchronous pulleys 25 are fixedly fitted onto the outside of the three sets of synchronous belts 24 located on the same side. The output shaft of the servo motor 23 drives the stretching roller 21 to rotate, stretching and winding the plastic film longitudinally. At the same time, the stretching roller 21 drives the incomplete gear 44 and the one-way ratchet 34 to rotate synchronously through the synchronous belts 24 and the synchronous pulleys 25 on the same side.

[0038] During operation, the one-way ratchet 34 is driven synchronously by the outer synchronous pulley 25 and the synchronous belt 24 to rotate in one direction, so that the plastic film passing through the lower guide roller 33 can only rotate in the stretching direction when stretched, avoiding reverse rotation that would cause the plastic film to stretch and shrink longitudinally.

[0039] Simultaneously, as the one-way ratchet 34 rotates periodically, the externally engaged pawl 35 is intermittently lifted by the ratchet teeth, compressing the first torsion spring 352 to store energy, driving the side connecting plate 36 and the first hollow sleeve 37 to perform high-frequency, small-amplitude reciprocating oscillations. During the beating process of the first hollow sleeve 37, because the plastic film is in a taut state, the torque on the film surface continues to be transmitted backward in the stretching direction, preventing it from being wound onto the stretching roller 21 and causing uneven twisting. The first hollow sleeve 37 makes gentle contact with the surface of the plastic film, and through periodic beating, shakes off the stubborn industrial dust adhering to the surface, making it easier for it to be adsorbed and removed by the dust removal and adsorption plates 61 on both sides, improving the cleanliness of the film surface and ensuring the quality stability of subsequent stretching processes.

[0040] In addition, the upper guide roller 32 can drive the slider 313 to move up and down along the linear slide rail 311 via the cylinder 312, flexibly adjusting the gap between it and the lower guide roller 33 to adapt to plastic films of different thicknesses and ensure stable tension during the guiding process.

[0041] The working principle of this invention is as follows: When in use, one end of the plastic film to be stretched is first passed through the gap between the upper guide roller 32 and the lower guide roller 33 in the two sets of guide film mechanisms 300, and then fixedly wound around the outer circumference of the stretching roller 21.

[0042] Then, the servo motor 23 is started, and the output shaft of the servo motor 23 drives the stretching roller 21 to rotate, stretching and winding the plastic film longitudinally.

[0043] Meanwhile, the stretching roller 21 is synchronously driven by the synchronous belt 24 and synchronous pulley 25 on the same side to rotate the incomplete gear 44 and the one-way ratchet 34. When the incomplete gear 44 rotates, it alternately meshes with the positioning rack 431 at the top and bottom of the inner wall of the positioning block 43, pushing the positioning block 43 to reciprocate linearly along the guide rail 42, which drives the fixed plate 52 and the second hollow sleeve 55 of the film stretching mechanism 500 to reciprocate synchronously. The second hollow sleeve 55 contacts the surface of the plastic film and reciprocates the film during the stretching process. When the top pressure roller 551 moves with the fixed plate 52, it rolls along the bottom slope of the guide block 56. With the elastic force of the second torsion spring 54, the connecting rod 51 drives the fixed plate 52 to swing back and forth slightly, further enhancing the tension and flatness of the film and effectively relieving the torsional torque during stretching.

[0044] When the one-way ratchet 34 rotates, it drives the lower guide roller 33 to rotate unidirectionally along the film stretching direction, preventing the film from shrinking in the opposite direction. At the same time, the teeth of the one-way ratchet 34 intermittently push up the pawl 35, compressing the first torsion spring 352, causing the side connecting plate 36 to drive the first hollow sleeve 37 to swing at a high frequency and small amplitude, tapping the film surface to shake off stubborn dust, which is then absorbed and removed by the dust removal adsorption plates 61 on both sides. During the tapping process of the first hollow sleeve 37, since the plastic film is in a taut state, the torque on the film surface continues to be transmitted backward in the stretching direction, preventing it from being wound onto the stretching roller 21 and causing uneven twisting.

[0045] To accommodate plastic films of different thicknesses, the cylinder 312 can drive the slider 313 to move up and down along the linear slide rail 311, adjusting the gap between the upper guide roller 32 and the lower guide roller 33 to ensure the stability of the guiding and stretching process. Through the coordinated operation of its various mechanisms, the entire device achieves efficient stretching, smooth winding, and surface dust removal of the plastic film, thus improving the quality of the finished film.

[0046] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A longitudinal stretching device for plastic film, comprising a worktable (100), characterized in that, Also includes: A stretching film winding mechanism (200) is installed on one side of the top of the worktable (100). The stretching film winding mechanism (200) includes a stretching roller (21) and is used to stretch and wind a plastic film longitudinally. A guiding film mechanism (300) is installed on the top of the worktable (100) and symmetrically distributed on both sides away from the stretching film winding mechanism (200). The guiding film mechanism (300) includes an upper guiding roller (32) and a lower guiding roller (33). The guiding film mechanism (300) is used for longitudinal guidance of the plastic film and to relieve torque. A reciprocating drive mechanism (400) is symmetrically distributed on both sides of the worktable (100). The reciprocating drive mechanism (400) includes a positioning block (43). The reciprocating drive mechanism (400) is used to drive reciprocating motion. A film tensioning mechanism (500) is installed between the two sets of reciprocating drive mechanisms (400), the film tensioning mechanism (500) includes a fixing plate (52), and the film tensioning mechanism (500) is used to tension the plastic film; A dust removal mechanism (600) is installed between the two sets of the guide film mechanism (300). The dust removal mechanism (600) includes a dust removal adsorption plate (61) and is used to adsorb and remove industrial dust from the surface of the plastic film.

2. The longitudinal stretching device for plastic film according to claim 1, characterized in that: An outer protective net (11) is fixedly installed in the middle of the periphery of the workbench (100). The stretching film winding mechanism (200) also includes a bearing seat (22) fixedly installed at the periphery end of the workbench (100). The stretching roller (21) is rotatably installed between two sets of bearing seats (22). A servo motor (23) is fixedly installed on the bearing seat (22) located at one end of the front of the workbench (100). The output end of the servo motor (23) is fixedly connected to the end shaft of the stretching roller (21).

3. The longitudinal stretching device for plastic film according to claim 2, characterized in that: The guiding film mechanism (300) also includes a fixed seat (31) fixedly installed on the top of the worktable (100) away from the stretching film winding mechanism (200). The dust removal adsorption plate (61) is fixedly installed on the side of the fixed seat (31) away from the reciprocating drive mechanism (400). A linear slide rail (311) is fixedly installed on one side of the inner wall of the fixed seat (31). A cylinder (312) is fixedly installed on the top of the fixed seat (31). A slider (313) is slidably connected to the outside of the linear slide rail (311). The two ends of the upper guide roller (32) are respectively rotatably installed between the two sets of sliders (313). The lower guide roller (33) is rotatably installed on the inner wall of the fixed seat (31) near the bottom. The upper guide roller (32) and the lower guide roller (33) are in parallel clearance fit. The telescopic end of the cylinder (312) is fixedly connected to the top of the corresponding slider (313) on the same side.

4. The longitudinal stretching device for plastic film according to claim 3, characterized in that: One-way ratchet fibers (34) are fixedly sleeved on the two ends of the lower guide roller (33). Connecting seats (351) are fixedly installed on the inner walls of the two sets of fixed seats (31) near the bottom. Pawls (35) are rotatably installed on the outer side of the connecting seats (351) through the rotating shaft. A first torsion spring (352) is fixedly installed between the pawls (35) and the connecting seats (351). The pawls (35) mesh with the one-way ratchet fibers (34) on the same side. Side connecting plates (36) are fixedly installed at the ends of the rotating shafts on the outer side of the two sets of pawls (35). A first connecting roller is fixedly installed in the U-shaped groove at the end of the two sets of side connecting plates (36) away from the pawls (35). A first hollow sleeve (37) is movably sleeved on the outside of the first connecting roller.

5. The longitudinal stretching device for plastic film according to claim 4, characterized in that: The reciprocating drive mechanism (400) includes two sets of side seats (41) fixedly installed at the top edge of the worktable (100). Guide slide rails (42) are fixedly installed on the inner sides of the two sets of side seats (41). A positioning block (43) is slidably connected inside the guide slide rail (42). A positioning rack (431) is integrally formed on the top and bottom of the inner wall of the positioning block (43).

6. The longitudinal stretching device for plastic film according to claim 5, characterized in that: Two sets of side seats (41) have incomplete gears (44) rotatably mounted on the middle part of their inner sides via a rotating shaft. The incomplete gears (44) are located in the inner wall of the positioning block (43) and mesh with the positioning rack (431).

7. The longitudinal stretching device for plastic film according to claim 6, characterized in that: Positioning seats (53) are fixedly installed on the inner side of the two sets of guide rails (42), and a connecting rod (51) is rotatably installed between the two sets of positioning seats (53). The fixing plate (52) is fixedly installed in the middle of the periphery of the connecting rod (51), and a second torsion spring (54) is fixedly installed between the two ends of the connecting rod (51) and the corresponding positioning seat (53).

8. The longitudinal stretching device for plastic film according to claim 7, characterized in that: A second connecting roller is fixedly installed on the U-shaped groove on the side of the fixed plate (52) away from the connecting rod (51), and a second hollow sleeve (55) is movably sleeved on the outside of the second connecting roller. Top pressure yarn (551) is fixedly installed at both ends of the second connecting roller in the U-shaped groove on the side of the fixed plate (52) away from the connecting rod (51). A guide block (56) is provided on the top of the top pressure yarn (551), and a connecting frame (561) is fixedly installed between the guide block (56) and the inner wall of the side seat (41).

9. A longitudinal stretching device for plastic film according to claim 8, characterized in that: Synchronous belts (24) are fixedly sleeved on the outer shafts of the stretching roller (21), the unidirectional spindle (34), and the incomplete gear (44) located on the same side, and synchronous belt yarns (25) are fixedly sleeved on the outside of the three sets of synchronous belts (24) located on the same side.

10. The stretching method of the longitudinal stretching device for plastic film according to claim 9, characterized in that, Includes the following steps: S1. Threading and fixing: Thread the end of the plastic film to be stretched between the two sets of fixing seats (31), pass through the inside of the dust removal adsorption plate (61), then pass between the upper guide roller (32) and the lower guide roller (33), and finally fix the end of the film to the outside of the stretching roller (21). S2, clamping and positioning: start the cylinder (312), the cylinder (312) drives the slider (313) to move down along the linear slide rail (311), so that the upper guide roller (32) moves down to cooperate with the lower guide roller (33) to clamp the plastic film and complete the pre-stretch positioning; S3, Stretch and wind: Start the servo motor (23), the servo motor (23) drives the stretching roller (21) to rotate at a constant speed, and continuously stretch and wind the plastic film longitudinally. S4. Dust removal: During the process of the slider (313) moving down and clamping, the pawl (35) moves down and pushes the unidirectional ratchet (34) to rotate, which drives the lower guide roller (33) to rotate and drives the side connecting plate (36) to swing back and forth. The first hollow sleeve (37) shakes the film to make the surface dust fall off and be adsorbed by the dust removal adsorption plate (61). S5. Reciprocating film winding: During the stretching and winding process, the stretching roller (21) drives the incomplete gear (44) to rotate via synchronous transmission. The incomplete gear (44) drives the positioning block (43) and the film winding mechanism (500) to reciprocate. The second hollow sleeve (55) continuously reciprocates to flatten and tighten the film surface, relieving the torsional torque, until the longitudinal stretching process of the entire plastic film is completed.

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