A plastic film cutting mechanism

Abstract

This application discloses a plastic film cutting mechanism, relating to the field of cutting equipment technology. It includes a frame, with a platform fixedly connected inside the frame. A film-pulling device for conveying plastic film is provided on the top surface of the frame. A film-cutting mechanism for cutting the plastic film is provided on the top surface of the platform. The film-cutting mechanism includes a main cutting blade for cutting the plastic film and a fixed base. A cylinder for driving the main cutting blade is fixedly connected to the top surface of the fixed base. A fixed frame is fixedly connected to the top surface of the cylinder. A protective sleeve, which is slidably connected to and fixedly connected to the output end of the cylinder and protects the cylinder output end, is slidably connected inside the fixed frame. This application utilizes the side of the externally mounted cutting blade to avoid the problem of internal space congestion caused by a built-in cylinder, reducing the risk of mechanical interference, simplifying the internal component layout, and limiting the upward movement distance of the cutting blade, thus improving the adaptability of the cutting device.

Description

Technical Field

[0001] This application relates to the field of cutting equipment technology, and in particular to a plastic film cutting mechanism. Background Technology

[0002] Plastic film generally refers to films made of polyvinyl chloride, polyethylene, polypropylene, polystyrene, and other resins, used for packaging and as a coating layer. Plastic packaging and plastic packaging products are gaining an increasingly larger market share, especially composite plastic flexible packaging, which is widely used in the food, pharmaceutical, and chemical industries. Food packaging accounts for the largest proportion, including beverage packaging, frozen food packaging, retortable food packaging, and fast food packaging. These products have brought great convenience to people's lives. Among the many types of plastic film, polyethylene film is widely used as a raw material for packaging bags, food bags, and various containers due to its colorless, tasteless, odorless, translucent, non-toxic, and insulating properties.

[0003] In existing technologies, when cutting plastic film, the drive cylinder is usually built into the top of the cutting blade. When the film cutting device faces objects of different heights, it needs to be adjusted by vertical movement. However, building the drive cylinder into the top of the cutting blade reduces the space above the cutting blade, making it impossible to move higher when cutting taller objects, thus limiting the adaptability of the film cutting device. Utility Model Content

[0004] To address the limitation imposed by the built-in cylinder on the adaptability of the film cutting device, this application provides a plastic film cutting mechanism.

[0005] The plastic film cutting mechanism provided in this application adopts the following technical solution:

[0006] A plastic film cutting mechanism includes a frame, a platform fixedly connected inside the frame, and a film feeding device for conveying plastic film on the top surface of the frame.

[0007] The top surface of the platform is provided with a film cutting mechanism for cutting plastic film. The film cutting mechanism includes a main cutting blade for cutting plastic film and a fixed base. The top surface of the fixed base is fixedly connected to a cylinder for driving the main cutting blade to cut. The top surface of the cylinder is fixedly connected to a fixed frame. The inside of the fixed frame is a protective sleeve that is fixedly connected to the output end of the cylinder and protects the output end of the cylinder.

[0008] By adopting the above technical solution, the frame serves as the main framework supporting the entire machine structure, providing rigid support and installation benchmarks to ensure the stability of equipment operation. The table plate is fixed inside the frame and serves as the installation platform for the film cutting mechanism. It must ensure horizontal accuracy to maintain cutting consistency. The film pulling device under the head is located on the top surface of the frame. It drives the plastic film to be fed at a uniform speed through a precision roller group and a servo motor. It is equipped with a tension sensor to adjust the film tension in real time to prevent the film from wrinkling or shifting during cutting. The film cutting mechanism is used to cut the plastic film. The main cutting blade is the moving blade component that performs film cutting. The fixed base is the mounting base for the cylinder. The fixed frame is the protective bracket for the top of the cylinder. The protective sleeve is slidably nested inside the fixed frame and covers the cylinder piston rod.

[0009] Preferably, the platform is symmetrically fixed with columns inside, and each column has a lifting block slidably connected to its outer surface for controlling the movement of the cutting blade. One side of each lifting block is fixedly connected to a fixing plate that is fixedly connected to a fixing seat.

[0010] By adopting the above technical solution, the column serves as the vertical guide rail for the lifting block. The lifting block is connected to the column via a linear bearing, which converts the cylinder thrust into the vertical movement of the cutting blade. The fixing plate is used to connect the lifting block and the fixing seat, transmitting the cutting force and dispersing the stress.

[0011] Preferably, a fixing ring is rotatably connected to the side of the fixing plate near the cylinder, and a connecting ring is rotatably connected to one side of the fixing plate.

[0012] By adopting the above technical solution, the fixed ring is the rotation fulcrum of the main blade swing arm, and the connecting ring is rotatably connected to the fixed plate, thereby decoupling the force transmission path between the cylinder and the main blade swing arm.

[0013] Preferably, the output end of the cylinder is fixedly connected to a spherical bearing, a connecting block is rotatably connected to one side of the spherical bearing, and a main blade swing arm that is fixedly connected to a fixed ring is slidably connected inside the connecting block.

[0014] By adopting the above technical solution, the spherical bearing is used to absorb the installation coaxiality error, and the connecting block is used to convert the linear motion of the cylinder into the arc trajectory of the swing arm.

[0015] Preferably, a connecting sleeve fitted on the outer surface of the main blade swing arm is fixedly connected between the connecting block and the connecting ring.

[0016] By adopting the above technical solution, the connecting sleeve is fitted outside the main blade swing arm to prevent film debris from entering the main blade swing arm.

[0017] Preferably, a main blade central shaft that is rotatably connected to the side of the fixing ring away from the connecting ring is fixedly connected, and fixing blocks are symmetrically fixedly connected to the outer surface of the main blade central shaft.

[0018] By adopting the above technical solution, the main blade central shaft passes through the core rotating shaft of the fixed plate and is plated with hard chrome to reduce the coefficient of friction. The fixed blocks are symmetrically fixed to the central shaft to transmit the rotational motion to the main blade of the cutting film.

[0019] Preferably, the side of the fixing block away from the central axis of the main blade is rotatably connected to the main cutting blade that slides on the inner wall of the fixing plate, and a plurality of torsion springs are linearly arrayed on the outer surface of the main cutting blade.

[0020] By adopting the above technical solution, a linear array of torsion springs is distributed on the surface of the main cutting blade to provide constant pressure contact force between the blade and the film.

[0021] Preferably, an auxiliary plate is fixedly connected to the side of the fixing plate away from the fixing ring, a film cutting sub-blade is fixedly connected to one side of the fixing plate, a film forming roller is rotatably connected inside the fixing plate, and an air blowing pipe is provided on the top surface of the fixing plate.

[0022] By adopting the above technical solution, the secondary cutting blade is a fixed blade holder, which forms a shearing combination with the main cutting blade. The film-forming roller is coated with silicone to flatten the film edge after cutting and eliminate curling. The air blowing pipe is connected to compressed air to blow away debris from the blade surface at the moment of cutting and to cool the blade.

[0023] In summary, this application includes at least one of the following beneficial technical effects:

[0024] 1. By utilizing the side of the externally mounted cylinder cutting blade, the problem of crowded internal space in the fixed plate caused by the internal cylinder is avoided, the risk of mechanical interference is reduced, the internal component layout is made simpler, and the upward movement distance of the cutting blade is limited, thus improving the adaptability of the cutting device.

[0025] 2. By using a compressible connecting sleeve between the cylinder output shaft and the main blade swing arm, the impact force during the cutting process is effectively absorbed, the blade vibration is reduced, and the cutting accuracy is improved. In addition, the rotating connection structure between the main blade swing arm and the fixed plate allows the blade to adapt to the slight deformation of the film during the cutting process, reducing the risk of wrinkles or scratches. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of this application;

[0027] Figure 2 This is a schematic diagram of the internal structure of the rack in this application;

[0028] Figure 3 This is a schematic diagram of the column connection structure in this application;

[0029] Figure 4 This is a schematic diagram of the connection structure of the membrane cutting swing arm in this application;

[0030] Figure 5 This is a schematic diagram of the connection structure of the main blade central axis in this application;

[0031] Figure 6 This is a schematic diagram of the connection structure of the membrane cutting auxiliary blade in this application.

[0032] Attached reference numerals: 1. Frame; 2. Casters; 3. Front door; 4. Conveying and feeding device; 5. Table; 6. Film pulling device at the machine head;

[0033] 71. Column; 72. Lifting block; 73. Fixing plate; 74. Fixing base; 75. Cylinder; 76. Fixing frame; 77. Protective sleeve; 78. Joint bearing; 79. Connecting block; 710. Main blade swing arm;

[0034] 711. Retaining ring; 712. Connecting sleeve; 713. Connecting ring; 714. Main blade central shaft; 715. Fixing block; 716. Film cutting main blade; 717. Torsion spring;

[0035] 718. Auxiliary plate; 719. Film cutting auxiliary knife; 720. Film forming roller; 721. Air blowing pipe. Detailed Implementation

[0036] The following is in conjunction with the appendix Figures 1-6 This application will be described in further detail.

[0037] This application discloses a plastic film cutting mechanism.

[0038] Reference Figure 1 , Figure 2 A plastic film cutting mechanism includes a frame 1. Casters 2 are fixedly connected to the bottom surface of the frame 1. The casters 2 are 500KG Foma leveling wheels, nylon flat plates, with a hole spacing of 70mm x 70mm. A front door 3 is hinged to the side of the frame 1. A conveying and feeding device 4 for conveying packaging boxes is fixedly installed on the side of the frame 1. A platform 5 is fixedly connected to the middle of the inner wall of the frame 1, and the conveying and feeding device 4 is located on the top surface of the platform 5 and extends through the interior of the front door 3. A machine head lower film pulling device 6 is fixedly installed on the top surface of the inner wall of the frame 1. The machine head lower film pulling device 6 is used to convey plastic film. The packaging boxes conveyed by the conveying and feeding device 4 are positioned below the machine head lower film pulling device 6. A film cutting mechanism is fixedly installed on the top surface of the platform 5. The film cutting mechanism is used to cut plastic film and is located below the machine head lower film pulling device 6.

[0039] In use, the packaging box is transported to the position where it needs to be wrapped with film by the conveying and feeding device 4. Then, the plastic film is covered on the surface of the packaging box by the film pulling device 6, and the plastic film is cut by the film cutting mechanism.

[0040] Reference Figure 3 , Figure 4The top surface of the table plate 5 is equipped with a film cutting mechanism, which includes symmetrically fixedly connected columns 71 inside the table plate 5. The outer surface of the columns 71 is serrated, and the outer surface of the columns 71 is slidably connected to the lifting blocks 72. The lifting blocks 72 are used to control the movement of the main cutting blade 716. The opposite surfaces of the two lifting blocks 72 are fixedly connected to the fixed plate 73. The bottom surface of the fixed plate 73 is fixedly connected to the fixed seat 74. The side of the fixed seat 74 away from the fixed plate 73 is rotatably connected to the housing of the cylinder 75. The output shaft of the cylinder 75 is fixedly connected to the bottom of the joint bearing 78. The cylinder 75 is close to the joint bearing. A fixed frame 76 is fixedly connected to one side of the 78. A protective sleeve 77 is fixedly connected to the outer surface of the spherical bearing 78, and the protective sleeve 77 is slidably connected inside the fixed frame 76. The protective sleeve 77 is used to protect the output shaft of the cylinder 75. The interior of the fixed plate 73 is rotatably connected to and communicates with the fixed ring 711. The side of the fixed plate 73 near the fixed ring 711 is rotatably connected to the connecting ring 713. The side of the spherical bearing 78 near the fixed ring 711 is rotatably connected to the connecting block 79. The interior of the connecting block 79 is slidably connected to the main blade swing arm 710, and the main blade swing arm 710 is fixedly connected to the fixed ring 711.

[0041] In use, the extension of the output end of the cylinder 75 causes the joint bearing 78, which is fixedly connected to the output end of the cylinder 75, to move. The movement of the joint bearing 78 causes the protective sleeve 77, which is fixedly connected to the joint bearing 78, to move together, so that the protective sleeve 77 extends inside the fixed frame 76. The protective sleeve 77 extends and retracts synchronously with the extension and retraction of the output end of the cylinder 75, protecting the output end of the cylinder 75 inside the protective sleeve 77.

[0042] Reference Figure 4 , Figure 6The connecting block 79 and the connecting ring 713 are fixedly connected to the connecting sleeve 712 between their opposing surfaces. The connecting sleeve 712 is fitted onto the outer surface of the main blade swing arm 710 and is telescopic, effectively absorbing the impact force during the cutting process and reducing blade vibration, thereby improving cutting accuracy. One side of the fixing ring 711 is fixedly connected to the main blade central axis 714, which is located away from the connecting ring 713. The main blade central axis 714 is rotatably connected inside the fixing plate 73. The outer surface of the main blade central axis 714 is fixedly connected to two fixing blocks 715, which are symmetrically arranged. One side of the fixing block 715 is slidably connected to the film cutting main blade 716, which is located away from the main blade central axis 710. On one side of 14, the main cutting blade 716 slides on the inner wall of the fixed plate 73. Several torsion springs 717 are linearly arrayed on the outer surface of the main cutting blade 716. An auxiliary plate 718 is fixed on the side of the fixed plate 73 away from the central axis 714 of the main blade. A secondary cutting blade 719 is fixedly connected to the lower side of the fixed plate 73 near the auxiliary plate 718. The bottom surface of the secondary cutting blade 719 is located above the top surface of the main cutting blade 716, and there is a gap between the bottom surface of the secondary cutting blade 719 and the top surface of the main cutting blade 716. This gap is used for the plastic film to pass through. The inner center of the fixed plate 73 is rotatably connected to the film forming roller 720. An air blowing pipe 721 is fixed on the top surface of the fixed plate 73, and the air blowing pipe 721 is located above the film forming roller 720.

[0043] In use, the spherical bearing 78 extends, causing the connecting block 79, which is rotatably connected to the spherical bearing 78, to move and compress the connecting sleeve 712. The main blade swing arm 710 slides inside the connecting block 79, thereby rotating the main blade swing arm 710. The rotation of the main blade swing arm 710 causes the fixing ring 711, which is fixedly connected to the main blade swing arm 710, to rotate, which in turn causes the main blade central shaft 714 to rotate. The rotation of the main blade central shaft 714 causes the fixing block 715, which is fixedly connected to the main blade central shaft 714, to rotate, thereby pushing the film cutting main blade 716 to move closer to the film cutting secondary blade 719. This achieves the cutting of the plastic film between the bottom surface of the film cutting secondary blade 719 and the top surface of the film cutting main blade 716.

[0044] In this device, the torsion spring 717 primarily uses torque to represent its elastic effect, and its calculation formula is usually based on the spring's stiffness (elastic coefficient). The basic formula is: M = K·θ, where: M is the torque generated by the torsion spring 717 upon recovery (the unit is usually N·m or lb·ft); θ is the torsion angle (in radians); and K is the stiffness of the torsion spring 717, representing the restoring torque generated per unit angle. For a standard circular cross-section torsion spring 717, the formula for calculating the stiffness K is:

[0045] K = (G·d) 4 ) / (10.8·D·n) where: G is the shear modulus of the material (usually in N / m) 2(or psi); d is the diameter of the 717 torsion spring wire; D is the average diameter of the 717 torsion spring; n is the effective number of coils; the constant 10.8 is an empirical coefficient used to correct the mechanical distribution in actual use (this value may vary slightly under different designs and standards);

[0046] A sealing design can be added at the connection between the output end of cylinder 75 and the main blade swing arm 710. Fluororubber (FKM) sealing rings are used, which have high temperature resistance and corrosion resistance and are suitable for pneumatic equipment. The outer and inner diameters of the sealing rings should be designed according to the specific dimensions of cylinder 75. Generally, sealing products that meet the ISO 9001 standard can be selected to ensure that there is no leakage at the output end of cylinder 75.

[0047] A high-precision sliding guide or bearing can be added between the main blade swing arm 710 and the connecting ring 713. SKF linear guide rails with a precision grade of P4 can be used. This type of guide rail can effectively reduce errors and ensure that the main blade swing arm 710 remains highly stable during movement.

[0048] The connection between the lifting block 72 and the column 71 can use an IKO precision linear bearing (model: LWL20). This type of bearing has a low coefficient of friction and a high-precision motion trajectory, which can effectively prevent the lifting block 72 from shifting during movement.

[0049] A spring lock (e.g., a Parker pneumatic lock with locking function) can be added between the lifting block 72 and the fixed plate 73 to ensure that the lifting block 72 will not be displaced due to vibration or improper operation during the movement.

[0050] A SICK brand position sensor (model: MZ35) can be used. This sensor can accurately monitor the actual position of cylinder 75 and provide real-time feedback to the control system. Its measurement range can reach 500mm and its accuracy is 0.1mm, making it suitable for this type of cutting equipment.

[0051] The implementation principle of a plastic film cutting mechanism according to an embodiment of this application is as follows:

[0052] In operation, the packaging box is transported to the location where film packaging is required via the conveying and feeding device 4. Then, the film-pulling device 6 at the die head covers the surface of the packaging box with plastic film. Subsequently, the output end of the cylinder 75 extends, causing the spherical bearing 78 to move, which in turn moves the protective sleeve 77. This causes the protective sleeve 77 to extend inside the fixed frame 76, and its extension and retraction are synchronized with the extension and retraction of the output end of the cylinder 75, protecting the output end of the cylinder 75 within the protective sleeve 77. The spherical bearing 78 then extends. The connecting block 79, which is rotatably connected to the spherical bearing 78, moves, thereby compressing the connecting sleeve 712. The main blade swing arm 710 slides inside the connecting block 79, thereby rotating the main blade swing arm 710. The rotation of the main blade swing arm 710 drives the fixing ring 711, the main blade central shaft 714, and the fixing block 715 to rotate, thereby pushing the film cutting main blade 716 to move closer to the film cutting auxiliary blade 719. This achieves the cutting of the plastic film between the bottom surface of the film cutting auxiliary blade 719 and the top surface of the film cutting main blade 716.

[0053] The above are merely optional embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A plastic film cutting mechanism, characterized by: Includes a frame (1), with a platform (5) fixedly connected inside the frame (1), and a film feeding device (6) for conveying plastic film is provided on the top surface of the frame (1). The top surface of the platform (5) is provided with a film cutting mechanism for cutting plastic film. The film cutting mechanism includes a main cutting blade (716) for cutting plastic film and a fixed base (74). The top surface of the fixed base (74) is fixedly connected to a cylinder (75) for driving the main cutting blade (716) to cut. The top surface of the cylinder (75) is fixedly connected to a fixed frame (76). The inside of the fixed frame (76) is slidably connected to a protective sleeve (77) that is fixedly connected to the output end of the cylinder (75) and protects the output end of the cylinder (75).

2. The plastic film cutting mechanism according to claim 1, wherein: The platform (5) is symmetrically fixed with columns (71) inside. The outer surface of each column (71) is slidably connected with a lifting block (72) for controlling the movement of the cutting blade (716). One side of the lifting block (72) is fixedly connected with a fixing plate (73) that is fixedly connected to the fixing seat (74).

3. The plastic film cutting mechanism according to claim 2, wherein: The fixing plate (73) has a fixed ring (711) that rotates through and connects to the side of the cylinder (75) near the fixing plate (73), and a connecting ring (713) is rotatably connected to one side of the fixing plate (73).

4. The plastic film cutting mechanism according to claim 3, wherein: The output end of the cylinder (75) is fixedly connected to a spherical bearing (78), and a connecting block (79) is rotatably connected to one side of the spherical bearing (78). The main blade swing arm (710) is slidably connected inside the connecting block (79) and fixedly connected to the fixing ring (711).

5. A plastic film cutting mechanism according to claim 4, characterized in that: A connecting sleeve (712) sleeved on the outer surface of the main blade swing arm (710) is fixedly connected between the connecting block (79) and the connecting ring (713).

6. The plastic film cutting mechanism according to claim 5, wherein: The fixing ring (711) is fixedly connected to the main blade central shaft (714) rotatably connected inside the fixing plate (73) on the side away from the connecting ring (713), and the outer surface of the main blade central shaft (714) is symmetrically fixedly connected to the fixing blocks (715).

7. The plastic film cutting mechanism according to claim 6, wherein: The side of the fixed block (715) away from the central axis (714) of the main blade is rotatably connected to the main cutting blade (716) that slides on the inner wall of the fixed plate (73), and a number of torsion springs (717) are linearly arrayed on the outer surface of the main cutting blade (716).

8. The plastic film cutting mechanism according to claim 7, wherein: An auxiliary plate (718) is fixedly connected to the side of the fixed plate (73) away from the fixed ring (711). A film cutting sub-blade (719) is fixedly connected to one side of the fixed plate (73). A film forming roller (720) is rotatably connected inside the fixed plate (73). An air blowing pipe (721) is provided on the top surface of the fixed plate (73).

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