Blister forming device for meal boxes

Abstract

The application provides a blister forming device for a meal box, material conveying units are arranged on both sides of a heating unit and a forming unit, the material conveying units can continuously clamp both sides of a film material and drive the film material to linearly move, material pressing devices are arranged on one side or both sides of a cutting unit, execution ends of the material pressing devices can be close to or away from a film material surface, when the execution ends of the material pressing devices are close to the film material surface, execution ends of the cutting unit are away from the film material, the material pressing devices can drive the film material to linearly move, when the execution ends of the material pressing devices are away from the film material surface, the film material is in a tension releasing state, the execution ends of the cutting unit are close to the film material and cutting is performed. The blister forming device for the meal box can increase the force application points on the film material through the continuous clamping of both sides of the film material by the material conveying units, the film material can be orderly released and the film material surface is not polluted, so that subsequent orderly production and product quality are ensured.

Description

Technical Field

[0001] This invention belongs to the field of vacuum forming, and in particular relates to a vacuum forming device for a lunch box. Background Technology

[0002] Vacuum forming is a plastic processing technique that involves vacuum-forming a softened sheet of plastic onto a mold surface. It is primarily used in packaging, lighting, advertising, and decoration. The main advantages of vacuum-formed packaging are: saving raw materials, lightweight, convenient transportation, good sealing performance, and compliance with environmentally friendly packaging requirements; it can package any irregularly shaped product without the need for additional cushioning materials; the packaged product is transparent and visible, aesthetically pleasing, and easy to sell; it is also suitable for mechanized and automated packaging, facilitating modern management, saving manpower, and improving efficiency.

[0003] In existing technologies, to improve the processing efficiency of vacuum forming, continuous roll vacuum forming automated production is generally adopted. Usually, multiple forming units are set on a single vacuum forming mold, and then cut into individual vacuum forming products. This results in a large forming area. Before vacuum forming, the plastic film to be processed needs to be preheated locally. After preheating, the film softens. After linear stretching, the softened film will be stretched and deformed. In the case of a large forming area, this stretching deformation is disordered, which will cause the thickness of each surface of the vacuum formed product to be inconsistent, affecting product quality. Summary of the Invention

[0004] In view of this, the present invention aims to provide a thermoforming device for lunch boxes to solve the problem in the existing thermoforming production process that the film material needs to be preheated. When stretching the preheated and softened film material, the stretched film material is subjected to disordered deformation under tension, resulting in uneven thickness of various surfaces of the thermoformed product and poor product quality.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows: A thermoforming device for a lunchbox includes a heating unit, a forming unit, and a cutting unit arranged sequentially along a forming line. The heating unit, forming unit, and cutting unit are respectively mounted on a fixed frame. A feeding unit is located upstream of the heating unit, on which a roll of film material is mounted. The film roll is linearly laid flat on the heating unit via the feeding unit. The heating unit is used to preheat the film material. The forming unit is used to thermoform the film material. The cutting unit is used to cut the thermoformed product. Material conveying units are located on both sides of the heating unit and the forming unit. The material conveying units can continuously clamp both sides of the film material and drive the film material to move linearly. A material pressing device is located on one or both sides of the cutting unit. The actuating end of the material pressing device can approach or move away from the film material surface. When the actuating end of the material pressing device approaches the film material surface, the actuating end of the cutting unit moves away from the film material, and the material pressing device can drive the film material to move linearly. When the material pressing device moves away from the film material surface, the film material is in a state of released tension, and the actuating end of the cutting unit approaches the film material and performs cutting.

[0006] Furthermore, material conveying units are respectively provided on both sides of the membrane material, and the stroke of the material conveying units at least covers the processing paths of the heating unit and the forming unit. The material conveying unit includes a first conveyor belt, the inner ring of the first conveyor belt is respectively sleeved on the periphery of the first driving wheel and the first driven wheel, and the first driving wheel and the first driven wheel are respectively installed on the fixed frame. A first fixed frame is installed on the fixed frame, and the first fixed frame at least covers the processing paths of the heating unit and the forming unit. A first limiting groove is provided on the first fixed frame, and the two sides of the first conveyor belt are respectively slidably connected to the two sides of the first limiting groove. Pressure joints are evenly distributed along the circumference of the first conveyor belt, and the ends of the pressure joints can abut against the upper surface of the membrane material.

[0007] Furthermore, the pressure joint includes a first top tube, and the first conveyor belt has mounting holes evenly distributed around its circumference. A first top tube is fixedly installed in each mounting hole. A first ball is rotatably installed at one end of the first top tube, and a second ball is rotatably installed at the other end of the first top tube. The outer periphery of the first ball can be rotatably connected to the top of the first limiting groove, and the outer periphery of the second ball can be pressed against the upper surface of the membrane material.

[0008] Furthermore, a second fixed frame is arranged opposite to the first fixed frame below it. The second fixed frame is provided with a second limiting groove. A second conveyor belt is arranged inside the second fixed frame. The first conveyor belt and the second conveyor belt face each other and rotate synchronously. Second top tubes are evenly distributed along the circumference of the second conveyor belt. A third ball is provided at one end of the second top tube. The outer periphery of the third ball is tumbling to the second limiting groove. The other end of the second top tube is provided with a pressing hole. The pressing hole presses against the second ball to clamp the side of the membrane material.

[0009] Furthermore, the heated membrane material side is clamped by the pressure hole and the second ball to form an arc-shaped recessed indentation. Limiting units are respectively provided on both sides of the cutting unit. The limiting unit has a material passage gap. The arc-shaped recessed indentation is located in the material passage gap, and the thickness of the arc-shaped recessed indentation is greater than the thickness of the membrane material. The height of the material passage gap is not greater than the thickness of the arc-shaped recessed indentation. The membrane material side is clamped into the material passage gap through the arc-shaped recessed indentation.

[0010] Furthermore, the limiting unit includes a lower plate, an upper plate, and an adjusting bolt. The lower plate is fixedly installed on the fixed frame. One end of the adjusting bolt is rotatably connected to the lower plate, and the outer thread of the adjusting bolt is connected to the upper plate. A material passage gap is provided between the lower plate and the upper plate. Rotating the adjusting bolt can adjust the height of the material passage gap.

[0011] Furthermore, the forming unit includes an upper pressure plate and a lower pressure plate, which can move relative to each other. A template is installed at the lower end of the upper pressure plate, and a punch is provided at the lower end of the template. A die is installed at the upper end of the lower pressure plate, and a groove is provided on the die. The outer contour of the punch matches the inner contour of the groove. An air inlet and an air suction hole are provided on the punch. An air inlet pipe and an air suction pipe are provided on the upper pressure plate. The air inlet pipe can blow hot air onto the upper surface of the film material through the air inlet hole, and the air suction pipe can remove the hot air from the upper surface of the film material through the air suction hole. A cutting hole is provided on the die, and a cutting tool is slidably installed in the cutting hole. The upper edge of the cutting tool is used to cut the film material to form a positioning hole on the film material, and the cutting edge can press against the lower end of the template.

[0012] Furthermore, the lower end of the cutting tool is connected to the base plate via a mounting base, and a first linear module is provided at the lower end of the base plate. The first linear module is mounted on the lower pressure plate and is used to drive the cutting tool to rise and fall. The first linear module is a hydraulic cylinder of the prior art.

[0013] Furthermore, the mounting base has threads on its periphery, and a mounting hole is provided at one end of the mounting base. The cutting tool is a hollow cylindrical structure, and the inner diameter of the mounting hole is not greater than the periphery of the cutting tool. The cutting tool is installed in the mounting hole, and the cutting edge of one end of the cutting tool is located outside the mounting base. The periphery of the mounting base is slidably connected to the cutting hole. The inner ring of the mounting base is provided with an abutment ring, and the other end of the cutting tool abuts against the abutment ring, and the outer diameter of the cutting tool is greater than the inner diameter of the abutment ring.

[0014] Furthermore, a floating assembly is provided between the mounting base and the base plate. The floating assembly includes an upper floating plate and a lower floating plate. The upper floating plate is threaded to the periphery of the mounting base, and the lower floating plate is connected to the base plate. The upper floating plate is provided with multiple first sliding rods, and the lower floating plate is provided with multiple first sliding holes. The periphery of the first sliding rods is slidably connected to the first sliding holes, and the lower floating plate is provided with a first clearance hole. The lower periphery of the tool holder is located in the first clearance hole. Multiple rigid springs are provided between the upper floating plate and the lower floating plate. The multiple rigid springs are arranged parallel to each other, and the two ends of each rigid spring are respectively fixedly connected to the lower end of the upper floating plate and the upper end of the lower floating plate.

[0015] Furthermore, the inner wall of the cutter is a vertical wall, and the inner wall of the cutter is a collection structure for the waste material removed from the membrane material. The waste material removed by the cutter can be squeezed and stacked inside the cutter. A concave mold is installed at the upper end of the lower pressure plate, a floating component is set inside the lower pressure plate, and a receiving box is slidably set at the bottom of the lower pressure plate. The removed membrane material can fall into the receiving box. The lower pressure plate is installed on the base plate, and a second linear module is set at the lower end of the base plate. The second linear module is fixedly installed on the fixed frame or base.

[0016] Furthermore, the cutting unit includes an upper cutting plate and a mold base. The upper cutting plate can move relative to the mold base, or the mold base and the upper cutting plate can move relative to or towards each other. The mold base and the upper cutting plate are respectively set on a fixed frame or a foundation. The upper cutting plate is used to cut the film material. A positioning post is set on the upper cutting plate. The outer diameter of the positioning post is not greater than the inner diameter of the positioning hole, and the end of the positioning post is a conical or hemispherical structure. The periphery of the positioning post is slidably connected to the positioning hole to position the relative position of the film material and the upper cutting plate. The mold base is provided with a second clearance hole, which is coaxial with the positioning post. The material pressing device includes a first support plate, a central shaft, a rocker plate, and a conveying roller. The first support plate is installed on one side of the upper cutting plate. A pressure rod is set on the first support plate. The central shaft is fixedly installed in the middle of the rocker plate. The two ends of the central shaft are rotatably connected to the fixed frame. The lower end of the pressure rod presses against one end of the rocker plate. The other end of the rocker plate is rotatably provided with a conveying roller. The periphery of the conveying roller presses against the upper surface of the film material.

[0017] Furthermore, the first support plate has an L-shaped cross-section. The first side of the first support plate has a first elongated hole, in which a first locking bolt is slidably disposed. The outer periphery of the first locking bolt is threaded to the upper cutting plate. The first locking bolt is used to fix the relative position of the first support plate and the upper cutting plate. The second side of the first support plate has a second elongated hole, in which a pressure rod is slidably disposed. The outer periphery of the pressure rod is threaded to a lock nut, and a lock nut is provided at each end of the second side. The lock nut is used to fix the relative position of the pressure rod and the second side.

[0018] Furthermore, a U-shaped door panel is provided at one end of the rocker, and a conveying roller is installed at each end of the U-shaped door panel. Each conveying roller is pressed to the side of a film material, and the two conveying rollers rotate synchronously. A second sliding rod is provided on the U-shaped door panel, and a second sliding hole is provided on the first support plate. The outer periphery of the second sliding rod is slidably connected to the second sliding hole, and a counterweight is installed at the upper end of the second sliding rod.

[0019] Compared with the prior art, the vacuum forming device for the lunch box described in this invention has the following advantages: (1) The thermoforming device for the lunch box of the present invention has a material conveying unit that can continuously clamp both sides of the film material and drive the film material to move linearly. The film material heated by the heating unit will soften. The continuous clamping of both sides of the film material by the material conveying unit can increase the force application points on the film material, release the film material in an orderly manner, and not contaminate the surface of the film material, so as to ensure the orderly production and product quality in the future.

[0020] (2) In the thermoforming device for the lunch box described in this invention, the lifting and lowering of the cutting unit can drive the material pressing device to approach or move away from the surface of the film material, so that when the cutting unit cuts the film material, the film material is in a loose state, so as to reposition the film material cutting and ensure the cutting quality of the product. When the material pressing device provides linear moving power to the film material, the material conveying unit rotates synchronously, so that the film material moves in an orderly manner at the rotation speed of the material conveying unit, and the film material that first comes into contact with the moving power of the material pressing device is the film material that is cooled and shaped by the forming unit, so as to avoid stretching and deforming the film material.

[0021] (3) The thermoforming device for the lunch box of the present invention has pressure joints evenly distributed along the circumference on the first conveyor belt. The end of the pressure joint can abut against the upper surface of the film material. Material conveying units are respectively set on both sides of the film material. The pressure joints can press against both sides of the film material. Each pressure joint is a pressure point at a relative position of the film material. Through the circumferential movement of the first conveyor belt, multiple pressing heads can be arranged and pressed against both sides of the film material. When the material pressing device drives the film material to move, the first motor rotates synchronously, so that the film material moves forward linearly at the linear speed achieved by the stepping rotation of the first motor.

[0022] (4) The blister forming device for the lunch box of the present invention has a first limiting groove as a limiting structure for the first ball and the first top tube. The first ball facilitates the first top tube to slide into the first limiting groove, and the second ball can press against the upper surface of the film material so as to press and hold the film material in place.

[0023] (5) In the thermoforming device for the lunch box of the present invention, the side of the film material is clamped by the pressure hole and the second ball to form an arc-shaped recessed indentation. The arc-shaped recessed indentation is located in the material passage gap, and the thickness of the arc-shaped recessed indentation is greater than the thickness of the film material. The height of the material passage gap is not greater than the thickness of the arc-shaped recessed indentation. The side of the film material is clamped into the material passage gap through the arc-shaped recessed indentation. In practice, the recessed indentation is slightly scraped to the material passage gap. The recessed indentations on both sides of the film material allow the material passage gap to limit the relative position of the film material and not interfere with the linear movement of the film material. When the forming unit cuts the film material, the recessed indentation does not interfere with the secondary positioning of the film material. When the material pressing device moves the film material linearly, the film material can be straightened in the material passage gap due to the tension, and the relative position of the two sides of the film material is limited.

[0024] (6) The vacuum forming device for the lunch box of the present invention has a die with a cutting hole, and a cutting tool is slidably arranged in the cutting hole. The upper cutting edge of the cutting tool is used to cut the film material to form a positioning hole on the film material. The cutting edge can press against the lower end of the template so that the positioning hole can be cut out on the shaped film material by the cutting tool, which prepares for secondary positioning during the subsequent cutting unit cutting, so as to improve the cutting accuracy of the product and ensure the cutting quality of the product.

[0025] (7) In the thermoforming device for the lunch box described in this invention, multiple rigid springs are provided between the upper floating plate and the lower floating plate. The rigid springs are protective structures for the blade edge. During implementation, after the lower pressure plate and the upper pressure plate move and close the mold, the blade edge fully contacts the film material and abuts against the template. At this time, the rigid springs can achieve micro-deformation, which can protect the blade edge, improve the service life of the blade, and ensure that the blade edge has enough pressure to cut the film material.

[0026] (8) The thermoforming device for the lunch box described in this invention sets the inner wall of the blade as a vertical wall so that the cut waste can be naturally stacked into the blade. As the stacked waste increases, it gradually falls into the collection box, thereby realizing the automatic removal and collection of waste, reducing manual operation, and preventing waste from contaminating the product.

[0027] (9) In the thermoforming device for the lunch box of the present invention, the outer diameter of the positioning post is the same as the inner diameter of the positioning hole. The positioning post is inserted into the positioning hole to facilitate secondary positioning of the film material before cutting. The end of the positioning post is a conical or hemispherical structure to facilitate the positioning post to slide into the positioning hole. The positioning post slides into the corresponding positioning hole to facilitate secondary positioning of the cutting center point of the whole film material to ensure the dimensional accuracy of the individual product cutting and forming.

[0028] (10) In the thermoforming device for the lunchbox of the present invention, a counterweight is installed at the upper end of the second slide bar. The counterweight is used to provide contact pressure for the conveyor roller to press against the side of the film material, so as to ensure that the conveyor roller can effectively drive the film material to move linearly. The conveyor roller contacts the film material and drives the film material to move linearly. The first support plate and the pressure rod move synchronously with the upper cutting plate. The central shaft and the rocker plate are connected to the fixed frame. The second slide bar is slidably connected to the first support plate. When the upper cutting plate is pressed down, the pressure rod presses against one end of the rocker plate. The U-shaped door panel is restricted by the displacement trajectory of the second slide bar. The U-shaped door panel drives the conveyor roller to move upward. The lifting motion allows multiple conveying rollers to simultaneously disengage from the upper surface of the film material, ensuring that the film material is in a loose state when the positioning post is aligned with the positioning hole. When the upper cutting plate is raised, the pressure bar disengages from one end of the rocker plate. The U-shaped door panel is restricted by the displacement trajectory of the second sliding rod and the pressure of the configuration block. The U-shaped door panel drives the conveying rollers to descend, allowing multiple conveying rollers to simultaneously contact the upper surface of the film material. The conveying rollers drive the film material to move linearly, ensuring that after the positioning post disengages from the positioning hole, the preceding film material is transferred to the downstream process, and the film material to be cut is in a taut state. Attached Figure Description

[0029] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the vacuum forming device for the lunchbox according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the first fixed frame and the second fixed frame cooperating according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the first conveyor belt equipped with the first jacking pipe according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the second conveyor belt equipped with the second jacking pipe according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of the limiting unit described in an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of the lower pressure plate according to an embodiment of the present invention; Figure 7 This is a side view of the pressure plate according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the structure of the tool and the mounting base as described in an embodiment of the present invention; Figure 9 This is a cross-sectional schematic diagram of the tool and mounting base mating according to an embodiment of the present invention; Figure 10 This is a schematic diagram of the structure of the floating component described in an embodiment of the present invention; Figure 11 This is a schematic diagram of the structure of the lower floating plate according to an embodiment of the present invention; Figure 12 This is a schematic diagram of the upper cutting plate according to an embodiment of the present invention; Figure 13 This is a schematic diagram of the material pressing device according to an embodiment of the present invention.

[0030] Explanation of reference numerals in the attached figures: 1-Heating unit; 2-Forming unit; 21-Upper pressure plate; 211-Air inlet pipe; 212-Suction pipe; 22-Lower pressure plate; 221-Knife hole; 23-Knife; 24-Mounting base; 241-Abutting ring platform; 25-Floating component; 251-Upper floating plate; 252-Lower floating plate; 253-First slide bar; 254-Hard spring; 26-Receiving box; 27-Base plate; 3-Cutting unit; 31-Upper cutting plate; 32-Mold base; 33-Positioning post; 4-Material conveying unit; 41-First conveyor belt; 42-First fixed frame; 43-First limiting groove; 4 4-Pressure joint; 441-First jacking pipe; 442-First ball bearing; 443-Second ball bearing; 45-Second fixed frame; 46-Second conveyor belt; 47-Second jacking pipe; 48-Third ball bearing; 49-Pressure hole; 5-Material pressing device; 51-First support plate; 52-Central shaft; 53-Winged plate; 54-Conveying roller; 55-Pressure rod; 56-Counterweight; 57-First locking bolt; 58-Locking nut; 59-U-shaped door panel; 510-Second sliding rod; 6-Limiting unit; 61-Material passage gap; 62-Upper plate; 63-Lower plate; 64-Adjusting bolt; 7-Membrane material. Detailed Implementation

[0031] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0032] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0033] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0034] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0035] like Figures 1-13 As shown, the thermoforming device for the lunchbox includes a feeding unit, a heating unit 1, a forming unit 2, a cutting unit 3, and a unloading unit arranged sequentially along the forming line. The heating unit 1, forming unit 2, and cutting unit 3 are respectively mounted on a fixed frame. The feeding unit is located upstream of the heating unit 1. The feeding unit can be implemented using the feeding mechanism described in the patent titled "A Fully Automatic Thermoforming Machine for Thermoforming Products," patent number CN202511572907X, or other existing technologies can be used to meet the requirements of the feeding unit. The technical requirement is that the film material roll 7 can be installed, and the film material roll 7 is linearly laid flat on the heating unit 1 via the feeding unit. The heating unit 1 is used to preheat the film material 7. The heating unit 1 can be implemented using the heating mechanism described in the patent title: A Fully Automatic Molding Machine for Vacuum Forming Products, Patent No.: CN202511572907X, which is existing technology. Alternatively, other existing technologies can be used to ensure that the heating unit 1 can preheat the film material 7 below it to 80-200℃. The forming unit 2... The device is used for vacuum forming of film material 7. The cutting unit 3 is used to cut the vacuum-formed product, and a feeding unit is located downstream of the cutting unit 3. The feeding unit is used to pick up the cut individual products. The feeding unit can be implemented using the feeding mechanism described in the patent title "A Fully Automatic Vacuum Forming Machine," patent number CN202511572907X, which is existing technology. Alternatively, other existing technologies can be used, as long as the technical requirement is that the cut individual products can be transferred to other designated locations via suction cups. Heating unit... Material conveying units 4 are provided on both sides of the forming unit 1 and the molding unit 2. The material conveying units 4 can continuously clamp both sides of the film material 7 and move linearly with the film material 7 continuously. The film material 7, heated by the heating unit 1, softens. The continuous clamping of both sides of the film material 7 by the material conveying units 4 increases the points of force application on the film material 7 without contaminating its surface. The continuous linear movement with the film material 7 also reduces deformation and prevents contamination, ensuring orderly subsequent production and product quality. Material clamping devices 5 are provided on one or both sides of the cutting unit 3, such as... Figure 1 As shown, in this embodiment, material pressing devices 5 are provided on both sides of the cutting unit 3. The execution end of the material pressing device 5 can approach or move away from the surface of the film material 7. When the execution end of the material pressing device 5 approaches the surface of the film material 7, the execution end of the cutting unit 3 moves away from the film material 7, and the material pressing device 5 can drive the film material 7 to move linearly. When the material pressing device 5 moves away from the surface of the film material 7, the film material 7 is in a state of released tension, and the execution end of the cutting unit 3 approaches the film material 7 and performs cutting. When the forming unit 2 forms the film material 7, the rapid cooling of the profile will cause the entire profile surface to shrink and deform. When the cutting unit 3 cuts the entire profile... When cutting individual products, secondary positioning and cutting are required. The lifting and lowering of the cutting unit 3 can move the material pressing device closer to or away from the surface of the film material 7, so that the film material 7 is in a loose state when the cutting unit 3 cuts the film material 7, so as to reposition the film material 7 and ensure the cutting quality of the product. When the material pressing device 5 provides linear movement power to the film material 7, the material conveying unit 4 rotates synchronously, so that the film material 7 moves in an orderly manner at the rotation speed of the material conveying unit 4. The film material 7 that first comes into contact with the moving power of the material pressing device 5 is the film material 7 that has been cooled and shaped by the forming unit 2, so as to avoid stretching and deforming the film material 7.

[0036] Material conveying units 4 are respectively provided on both sides of the membrane material 7, and the stroke of the material conveying unit 4 at least covers the processing path of the heating unit 1 and the forming unit 2. That is, when the heating unit 1 preheats the surface of the membrane material 7, it will soften the surface of the membrane material 7, requiring the clamping of the material conveying unit 4 until the box unit is vacuum-formed. The material conveying unit 4 always maintains clamping on both sides of the membrane material 7, such as Figures 2-4As shown, the material conveying unit 4 includes a first conveyor belt 41. The inner ring of the first conveyor belt 41 is respectively fitted around the outer periphery of the first driving wheel and the first driven wheel. The first conveyor belt 41 is a conventional belt or chain. When the first conveyor belt 41 is selected as a belt, the first driving wheel and the first driven wheel are both selected as conventional synchronous pulleys. When the first conveyor belt 41 is selected as a chain, the first driving wheel and the first driven wheel are selected as sprockets, and the drive shaft of the first driving wheel is fixed to the first motor. The first driving wheel and the first driven wheel are respectively mounted on a fixed frame. A first fixed frame 42 is mounted on the fixed frame. The first fixed frame 42 at least covers the processing paths of the heating unit 1 and the forming unit 2. A first limiting groove 43 is provided, and the two sides of the first conveyor belt 41 are slidably connected to the two sides of the first limiting groove 43 respectively. The first conveyor belt 41 is evenly distributed with pressure joints 44 along the circumference. The end of the pressure joint 44 can abut against the upper surface of the membrane material 7. Material conveying units 4 are respectively provided on both sides of the membrane material 7. They can be pressed to both sides of the membrane material 7 through the pressure joints 44. Each pressure joint 44 is a pressing point of the membrane material 7 at a relative position. Through the circumferential movement of the first conveyor belt 41, multiple pressing heads can be arranged and pressed to both sides of the membrane material 7. When the material pressing device 5 drives the membrane material 7 to move, the first motor rotates synchronously stepping, so that the membrane material 7 moves forward linearly at the linear velocity achieved by the stepping rotation of the first motor.

[0037] The crimp connector 44 includes a first jacking pipe 441. In this embodiment, the first conveyor belt 41 is a belt, and the first driving wheel and the first driven wheel are both synchronous pulleys. The outer periphery of the first driving wheel and the first driven wheel is evenly distributed with recessed holes along the circumference. These recessed holes are adapted to the outer periphery of the first ball bearing 442. Multiple first driven wheels are set on the fixed frame. The wheel diameter and configuration can be set by the operator according to the working conditions, so as not to interfere with the rotation of the first conveyor belt 41 and to allow the first ball bearing 442 to roll and slide into the first limiting groove 43. The first conveyor belt 41 has evenly distributed mounting holes along its circumference, and one first driven wheel is fixedly installed in each mounting hole. The first jacking tube 441 has a first ball bearing 442 rolled at one end and a second ball bearing 443 rolled at the other end. The outer periphery of the first ball bearing 442 can be rolled to the top of the first limiting groove 43, and the outer periphery of the second ball bearing 443 can press against the upper surface of the membrane material 7. The first limiting groove 43 is a limiting structure for the first ball bearing 442 and the first jacking tube 441. By setting the first ball bearing 442, the first jacking tube 441 can slide into the first limiting groove 43. The second ball bearing 443 can press against the upper surface of the membrane material 7 so as to press and hold the membrane material 7 in place.

[0038] A second fixed frame 45 is disposed opposite to the first fixed frame 42. The second fixed frame 45 has a second limiting groove and a second conveyor belt 46 is disposed within it. The first conveyor belt 41 and the second conveyor belt 46 face each other and rotate synchronously. In this embodiment, the second limiting groove has the same structure as the first limiting groove 43, and the first conveyor belt 41 and the second conveyor belt 46 have the same structure and transmission method. Second jacking pipes 47 are evenly distributed circumferentially on the second conveyor belt 46. A third ball bearing 48 is provided at one end, and the outer periphery of the third ball bearing 48 is rotatably connected to the second limiting groove. The other end of the second top tube 47 is provided with a pressing hole 49, which presses against the second ball bearing 443 to clamp the side of the membrane material 7. The second limiting groove is the limiting structure for the third ball bearing 48 and the second top tube 47. The pressing hole 49 and the second ball bearing 443 are the clamping structure for the membrane material 7. Furthermore, the heated side of the membrane material 7, clamped by the pressing hole 49 and the second ball bearing 443, can form an arc-shaped indentation, such as... Figure 1 and Figure 5 As shown, limiting units 6 are respectively provided on both sides of the cutting unit 3. A material feeding gap 61 is provided in the limiting unit 6. An arc-shaped recessed indentation is located in the material feeding gap 61, and the thickness of the arc-shaped recessed indentation is greater than the thickness of the film material 7. However, the thickness of the recessed indentation should not exceed 2 mm of the film material 7 to prevent jamming of the linear movement of the film material 7 during the conveying process. The height of the material feeding gap 61 is not greater than the thickness of the arc-shaped recessed indentation. The side of the film material 7 is engaged with the material feeding gap 6 through the arc-shaped recessed indentation. In the implementation, the indentation slightly scrapes against the material passage gap 61. The indentation on both sides of the film 7 allows the material passage gap 61 to limit the relative position of the film 7 without interfering with the linear movement of the film 7. When the forming unit 2 cuts the film 7, the indentation does not interfere with the secondary positioning of the film 7. When the material pressing device 5 moves the film 7 linearly, the film 7 can be straightened within the material passage gap 61 due to its tautness, and the relative position of the two sides of the film 7 is limited.

[0039] The limiting unit 6 includes a lower plate 63, an upper plate 62, and an adjusting bolt 64. The lower plate 63 is fixedly installed on the fixed frame. One end of the adjusting bolt 64 is rotatably connected to the lower plate 63, and the outer thread of the adjusting bolt 64 is connected to the upper plate 62. A material passage gap 61 is provided between the lower plate 63 and the upper plate 62. Rotating the adjusting bolt 64 can adjust the height of the material passage gap 61. The operator can adjust the height of the material passage gap 61 by rotating the adjusting bolt 64 to meet different working conditions and facilitate adjustment by the operator. In implementation, at least one adjusting bolt 64 must be provided. In this embodiment, in order to limit the displacement trajectory of the upper plate 62, such as... Figure 5 As shown, two adjusting bolts 64 are provided. In other embodiments, one adjusting bolt 64 and a slide rod that limits the displacement trajectory of the upper plate 62 can also be provided for assembly.

[0040] The forming unit 2 includes an upper pressure plate 21 and a lower pressure plate 22. The upper pressure plate 21 and the lower pressure plate 22 can move relative to each other. The method of achieving relative movement between the upper pressure plate 21 and the lower pressure plate 22 is existing technology. In implementation, existing linear modules such as hydraulic cylinders can be set at the upper end of the upper pressure plate 21 and the lower end of the lower pressure plate 22 respectively, as long as the upper pressure plate 21 and the lower pressure plate 22 can achieve opening and closing movements. A template is installed at the lower end of the upper pressure plate 21, and a punch is set at the lower end of the template. A die is installed at the upper end of the lower pressure plate 22. The die has a groove. The outer contour of the punch matches the inner contour of the groove. The punch is provided with an air inlet and an air suction hole. An air inlet pipe 211 and an air suction pipe 212 are respectively provided on the upper pressure plate 21. The air inlet pipe 211 can blow hot air onto the upper surface of the film material 7 through the air inlet hole, and the air suction pipe 212 can remove hot air from the upper surface of the film material 7 through the air suction hole. The method of hot air vacuum forming of the film material 7 using a punch and a die is a prior art. In this method, while the punch is pressed down, hot air is blown onto the surface of the film material 7 through the air inlet, softening the film material 7 and causing it to sink into the die. During the closing process of the punch and die, the hot air is extracted through the air inlet. After the mold is closed and the punch is raised, cold air is blown into the punch through the air inlet, causing the product formed around the punch to solidify and be demolded. In addition to the prior art, this embodiment also provides a cutting hole 221 on the die, with a cutting tool 23 slidably disposed within the cutting hole 221. The upper cutting edge of the cutting tool 23 is used to cut the film material 7, forming a positioning hole on the film material 7. The cutting edge can press against the lower end of the template, allowing the cutting tool 23 to cut positioning holes into the shaped film material 7, preparing for secondary positioning during subsequent cutting by the cutting unit 3, thereby improving the cutting accuracy and ensuring the cutting quality of the product.

[0041] The lower end of the cutter 23 is connected to the base plate 27 via a mounting base 24, and a first linear module is provided at the lower end of the base plate 27. The first linear module is mounted on the lower pressure plate 22 and is used to drive the cutter 23 to rise and fall. The first linear module is a hydraulic cylinder of the prior art, and as... Figure 8 and Figure 9As shown, the mounting base 24 has threads on its outer periphery, and a mounting hole is provided at one end of the mounting base 24. The tool 23 is a hollow cylindrical structure. The inner diameter of the mounting hole is not greater than the outer periphery of the tool 23. The tool 23 is interference-fitted into the mounting hole, and the cutting edge of one end of the tool 23 is located outside the mounting base 24. The outer periphery of the mounting base 24 is slidably connected to the tool hole 221. The inner ring of the mounting base 24 is provided with an abutment ring 241. The other end of the tool 23 abuts against the abutment ring 241, and the outer diameter of the tool 23 is greater than the inner diameter of the abutment ring 241 to prevent the tool 23 from being compressed. The relative position of the fixed cutter 23 is adjusted. During implementation, the first linear module can drive the mounting base 24 and the cutter 23 to slide along the axis of the cutter hole 221, so that the cutting edge of the cutter 23 can cut the film material 7. To prevent the cutting edge of the cutter 23 from being deformed due to excessive pressure, a floating component 25 is provided between the mounting base 24 and the base plate 27. The floating component 25 includes an upper floating plate 251 and a lower floating plate 252. The upper floating plate 251 is threaded to the periphery of the mounting base 24, and the lower floating plate 252 is connected to the base plate 27. The upper floating plate 251 is provided with multiple first sliding rods 253, and the lower floating plate 252 is provided with multiple first sliding holes. The outer periphery of the first sliding rods 253 is slidably connected to the first sliding holes. The first sliding rods 253 and the first sliding holes are limiting structures for the movement trajectory of the upper floating plate 251 relative to the lower floating plate 252. The lower floating plate 252 is provided with a first clearance hole, and the lower periphery of the tool holder is located in the first clearance hole to prevent the lower floating plate 252 from abutting against the end of the tool 23. Multiple hard springs 254 are provided between the upper floating plate 251 and the lower floating plate 252. 4. The rigid springs are arranged in parallel with each other. The two ends of each rigid spring 254 are fixedly connected to the lower end of the upper floating plate 251 and the upper end of the lower floating plate 252, respectively. The rigid spring 254 is a protective structure for the cutting edge of the cutter 23. During implementation, after the lower pressure plate 22 and the upper pressure plate 21 move to close the mold, the cutting edge of the cutter 23 fully contacts the film material 7 and abuts against the template. At this time, the rigid spring 254 can achieve micro-deformation, which can protect the cutting edge of the cutter 23, improve the service life of the cutter 23, and ensure that the cutting edge has enough pressure to cut the film material 7.

[0042] The inner wall of the cutter 23 is a vertical wall, and the inner wall of the cutter 23 is a collection structure for the waste material of the cut film 7. The waste material of the cut film 7 can be squeezed and stacked into the inside of the cutter 23. A concave mold is installed at the upper end of the lower pressure plate 22, and a floating component 25 is set inside the lower pressure plate 22. A receiving box 26 is slidably set at the bottom of the lower pressure plate 22. The cut film 7 can fall into the receiving box 26. The lower pressure plate 22 is installed on the base plate, and a second straight module is set at the lower end of the base plate. The second straight module is fixedly installed on the fixed frame or base. By making the inner wall of the cutter 23 a vertical wall, the cut waste material can be naturally stacked into the cutter 23. As the stacked waste material increases, it gradually falls into the receiving box 26, thus realizing the automatic removal and collection of waste material, reducing manual operation, and preventing waste material from contaminating the product.

[0043] The cutting unit 3 includes an upper cutting plate 31 and a mold base 32. The upper cutting plate 31 can move relative to the mold base 32, or the mold base 32 and the upper cutting plate 31 can move relative to or towards each other. The mold base 32 and the upper cutting plate 31 are respectively set on a fixed frame or foundation. The upper cutting plate 31 is used to cut the film material 7. The upper cutting plate 31 can cut the film material 7, which is formed by a punch, into independent products. In implementation, a break line should be set on the upper cutting plate 31 to prevent the independent products from falling off. This process is existing technology and can be referred to the connecting point avoidance opening described in the patent title: A fully automatic integrated forming machine for vacuum forming products, patent number: CN202511572907X. The difference between this embodiment and the existing technology is that a positioning post 33 is set on the upper cutting plate 31. The outer diameter of the positioning post 33 is the same as the inner diameter of the positioning hole. The positioning post 33 is inserted into the positioning hole to facilitate secondary positioning of the film material 7 before cutting. The end of the positioning post 33 is a conical or hemispherical structure. The outer periphery of the positioning post 33 is slidably connected to the positioning hole to position the relative position of the film material 7 and the upper cutting plate 31. The conical or hemispherical shape at the end facilitates the sliding of the positioning post 33 into the positioning hole. In this embodiment, three positioning posts 33 are provided. The three positioning posts 33 slide into the corresponding three positioning holes to perform secondary positioning of the cutting center point of the whole film material 7 to ensure the dimensional accuracy of the individual product cutting. The mold base 32 is provided with a second clearance hole. The second clearance hole is coaxial with the positioning post 33 to facilitate clearance of the positioning post 33 during movement.

[0044] like Figure 13As shown, the material pressing device 5 includes a first support plate 51, a central shaft 52, a rocker plate 53, and a conveying roller 54. The first support plate 51 is installed on one side of the upper cutting plate 31. A pressure rod 55 is provided on the first support plate 51. The central shaft 52 is fixedly installed in the middle of the rocker plate 53. The two ends of the central shaft 52 are rotatably connected to the fixed frame. The lower end of the pressure rod 55 presses against one end of the rocker plate 53. The other end of the rocker plate 53 is rotatably equipped with a conveying roller 54. The outer periphery of the conveying roller 54 presses against the upper surface of the film material 7. The cross-section of the first support plate 51 is L-shaped. The first support plate 51 has a first elongated hole on its first side, in which a first locking bolt 57 is slidably disposed. The first locking bolt 57 is threadedly connected to the upper cutting plate 31, and is used to fix the relative position of the first support plate 51 and the upper cutting plate 31. The second side of the first support plate 51 has a second elongated hole, in which a pressure rod 55 is slidably disposed. The pressure rod 55 is threadedly connected to a lock nut 58, and a lock nut 58 is provided at each end of the second side, for fixing the pressure rod 55 and the second support plate 31. On the sides, a U-shaped door plate 59 is provided at one end of the rocker arm 53. A conveyor roller 54 is installed at each end of the U-shaped door plate 59. Each conveyor roller 54 is pressed against the side of a membrane material 7, and the two conveyor rollers 54 rotate synchronously. A second slide rod 510 is provided on the U-shaped door plate 59, and a second sliding hole is provided on the first support plate 51. The outer periphery of the second slide rod 510 is slidably connected to the second sliding hole, and a counterweight 56 ​​is installed at the upper end of the second slide rod 510. The counterweight 56 ​​is used to provide pressure for the conveyor rollers 54 to press against the side of the membrane material 7. Contact pressure is applied to ensure that the conveyor roller 54 can effectively drive the membrane material 7 to move linearly. In implementation, the conveyor roller 54 needs to be equipped with a rotational power source, such as a servo motor (as in existing technology). The conveyor roller 54 connected to the servo motor is the active roller. The active roller can directly contact the membrane material 7 and can synchronously drive multiple passive rollers to rotate synchronously via a timing belt. These passive rollers are rotatably connected to the U-shaped gate plate 59, and are arranged parallel to each other. The periphery of each passive roller can roll onto the upper surface of the membrane material 7. Figure 13As shown, this embodiment is equipped with two passive rollers. During implementation, the first support plate 51 and the pressure rod 55 move synchronously with the upper cutting plate 31. The central shaft 52 and the rocker plate 53 are connected to the fixed frame. The second sliding rod 510 is slidably connected to the first support plate 51. When the upper cutting plate 31 is pressed down, the pressure rod 55 presses against one end of the rocker plate 53. The U-shaped door plate 59 is restricted by the displacement trajectory of the second sliding rod 510. The U-shaped door plate 59 drives the conveying roller 54 to move upward, so that multiple conveying rollers 54 can simultaneously disengage from the upper surface of the film material 7, ensuring that the film material 7 is in a loose state when the positioning post 33 is aligned with the positioning hole. When the upper cutting plate 31 is raised... The pressure bar 55 disengages from one end of the rocker arm 53. The U-shaped door panel 59 is restricted by the displacement trajectory of the second slide bar 510 and the pressure of the configuration block. The U-shaped door panel 59 drives the conveying roller 54 to move downward, so that multiple conveying rollers 54 can simultaneously contact the upper surface of the film material 7. The conveying roller 54 drives the film material 7 to move linearly, so as to ensure that after the positioning post 33 disengages from the positioning hole, the preceding film material 7 is transferred to the downstream process. The film material 7 to be cut is in a taut state, and the active roller drives the film material 7 to move linearly, which is the only power for the linear movement of the film material 7 in this application. The stepping speed of the film material 7 is controlled by the stepping speed of the material conveying unit 4.

[0045] The working process of the vacuum forming device for lunch boxes: When the upper cutting plate 31 is raised, it indicates that the individual product on the film material 7 has been cut. At this time, the conveying roller 54 contacts both sides of the film material 7, and the slightly larger indentation than the thickness of the film material 7 helps to increase the friction between the conveying roller 54 and the film material 7. The conveying roller 54 drives the cut film material 7 to the downstream process. At this time, the film material 7 is in a taut state. The first conveyor belt 41 and the second conveyor belt 46 of the synchronous material conveying unit 4 rotate synchronously, and the film material 7 is released according to the traveling speed of the first conveyor belt 41 and the second conveyor belt 46. The film material 7 of the forming unit 2 process is released to the cutting unit 3, and the film material 7 of the heating unit 1 is transferred to the forming unit 2 at the same time. During the movement of the film material 7, the material conveying unit 4 can continuously clamp both sides of the film material 7, and can provide as many clamping support points as possible for the film material 7 to prevent the softened film material 7 from deforming, until the first conveying unit 4 rotates. After the conveyor belt 41 and the second conveyor belt 46 move a preset distance, they stop driving. At this time, all the cut products have been moved to the downstream process. The vacuum-formed film material 7 has been transferred to the cutting unit 3. The preheated film material 7 enters the forming unit 2. The forming unit 2 closes the mold to vacuum-form the product. During the downward pressing of the upper cutting plate 31 of the cutting unit 3, the pressure rod 55 presses against one end of the rocker plate 53. The U-shaped door plate 59 is restricted by the displacement trajectory of the second slide rod 510. The U-shaped door plate 59 drives the conveyor roller 54 to move upward, so that multiple conveyor rollers 54 can simultaneously disengage from the upper surface of the film material 7. This ensures that when the positioning post 33 is aligned with the positioning hole, the film material 7 is in a loose state. When the positioning post slides into the positioning hole, it will drive the entire film material 7 to move and adjust the cutting center point to ensure the cutting size accuracy. This process continues until the upper cutting plate 31 and the mold base 32 close the mold and the cutting is completed. The above process is repeated.

[0046] The control method in this embodiment is controlled by a controller. The controller circuit can be implemented by simple programming by those skilled in the art. The power supply is also common knowledge in the art. Furthermore, this document is mainly used to protect mechanical devices, and the control method and circuit connection will not be explained in detail here.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A thermoforming device for a lunchbox, comprising a heating unit (1), a forming unit (2), and a cutting unit (3) arranged sequentially along a forming line, wherein the heating unit (1), the forming unit (2), and the cutting unit (3) are respectively mounted on a fixed frame, a feeding unit is provided upstream of the heating unit (1), a roll of film material (7) is mounted on the feeding unit, the roll of film material (7) is laid flat linearly on the heating unit (1) via the feeding unit, the heating unit (1) is used to preheat the film material (7), the forming unit (2) is used to thermoform the film material (7), the cutting unit (3) is used to cut the thermoformed product, and material conveying units (4) are provided on both sides of the heating unit (1) and the forming unit (2), characterized in that: The material conveying unit (4) can continuously clamp both sides of the membrane material (7) and drive the membrane material (7) to move linearly. The cutting unit (3) is provided with a material pressing device (5) on one or both sides. The execution end of the material pressing device (5) can be close to or away from the surface of the membrane material (7). When the execution end of the material pressing device (5) is close to the surface of the membrane material (7), the execution end of the cutting unit (3) is away from the membrane material (7). The material pressing device (5) can drive the membrane material (7) to move linearly. When the material pressing device (5) is away from the surface of the membrane material (7), the membrane material (7) is in a state of tension release. The execution end of the cutting unit (3) is close to the membrane material (7) and performs cutting. Material conveying units (4) are respectively provided on both sides of the membrane material (7), and the stroke of the material conveying unit (4) covers at least the processing path of the heating unit (1) and the forming unit (2). The material conveying unit (4) includes a first conveyor belt (41). The inner ring of the first conveyor belt (41) is respectively sleeved to the outer periphery of the first active wheel and the first passive wheel. The first active wheel and the first passive wheel are respectively installed on the fixed frame. The fixed frame is equipped with a first fixed frame (42). The first fixed frame (42) covers at least the processing path of the heating unit (1) and the forming unit (2). The first fixed frame (42) is provided with a first limiting groove (43). The two sides of the first conveyor belt (41) are respectively slidably connected to the two sides of the first limiting groove (43). The first conveyor belt (41) is evenly distributed with pressure joints (44) along the circumference. The end of the pressure joint (44) can abut against the upper surface of the membrane material (7). The crimp connector (44) includes a first jacking tube (441), and the first conveyor belt (41) has mounting holes evenly distributed around its circumference. Each mounting hole has a first jacking tube (441) fixedly installed in it. One end of the first jacking tube (441) is tumbledly mounted with a first ball (442), and the other end of the first jacking tube (441) is tumbledly mounted with a second ball (443). The outer periphery of the first ball (442) can be tumbledly connected to the top of the first limiting groove (43), and the outer periphery of the second ball (443) can be pressed against the upper surface of the membrane material (7). A second fixed frame (45) is arranged opposite to the first fixed frame (42). The second fixed frame (45) is provided with a second limiting groove. A second conveyor belt (46) is arranged inside the second fixed frame (45). The first conveyor belt (41) and the second conveyor belt (46) are opposite to each other and rotate synchronously. The second top tube (47) is evenly distributed along the circumference on the second conveyor belt (46). A third ball (48) is provided at one end of the second top tube (47). The outer periphery of the third ball (48) is rolled to the second limiting groove. The other end of the second top tube (47) is provided with a pressing hole (49). The pressing hole (49) and the second ball (443) press against each other to clamp the side of the membrane material (7). The cutting unit (3) includes an upper cutting plate (31) and a mold base (32). The upper cutting plate (31) can move relative to the mold base (32), or the mold base (32) and the upper cutting plate (31) can move relative to or towards each other. The mold base (32) and the upper cutting plate (31) are respectively set on a fixed frame or foundation. The upper cutting plate (31) is used to cut the film material (7). A positioning post (33) is set on the upper cutting plate (31). The outer diameter of the positioning post (33) is not greater than the inner diameter of the positioning hole, and the end of the positioning post (33) is a conical or hemispherical structure. The periphery of the positioning post (33) is slidably connected to the positioning hole for positioning the relative position of the film material (7) and the upper cutting plate (31). The mold base ( 32) is provided with a second clearance hole, which is coaxial with the positioning column (33). The material pressing device (5) includes a first support plate (51), a central shaft (52), a rocker plate (53) and a conveying roller (54). The first support plate (51) is installed on one side of the upper cutting plate (31). A pressure rod (55) is provided on the first support plate (51). The central shaft (52) is fixedly installed in the middle of the rocker plate (53). The two ends of the central shaft (52) are rotatably connected to the fixed frame. The lower end of the pressure rod (55) presses against one end of the rocker plate (53). The other end of the rocker plate (53) is rotatably provided with a conveying roller (54). The outer periphery of the conveying roller (54) presses against the upper surface of the film material (7).

2. The vacuum forming device for a lunchbox according to claim 1, characterized in that: The heated membrane material (7) is clamped by the pressure hole (49) and the second ball (443) to form an arc-shaped recessed groove. Limiting units (6) are provided on both sides of the cutting unit (3). A material passage gap (61) is provided in the limiting unit (6). The arc-shaped recessed groove is located in the material passage gap, and the thickness of the arc-shaped recessed groove is greater than the thickness of the membrane material (7). The height of the material passage gap is not greater than the thickness of the arc-shaped recessed groove. The side of the membrane material (7) is clamped into the material passage gap (61) through the arc-shaped recessed groove.

3. The vacuum forming device for a lunchbox according to claim 2, characterized in that: The limiting unit (6) includes a lower plate (63), an upper plate (62), and an adjusting bolt (64). The lower plate (63) is fixedly installed on the fixed frame. One end of the adjusting bolt (64) is rotatably connected to the lower plate (63), and the outer thread of the adjusting bolt (64) is connected to the upper plate (62). A material passage gap (61) is provided between the lower plate (63) and the upper plate (62). Rotating the adjusting bolt (64) can adjust the height of the material passage gap (61).

4. The vacuum forming device for a lunchbox according to claim 1, characterized in that: The molding unit (2) includes an upper pressure plate (21) and a lower pressure plate (22). The upper pressure plate (21) and the lower pressure plate (22) can move relative to each other. A template is installed at the lower end of the upper pressure plate (21), and a punch is set at the lower end of the template. A die is installed at the upper end of the lower pressure plate (22), and a groove is provided on the die. The outer contour of the punch matches the inner contour of the groove. An air inlet and an air suction hole are respectively provided on the punch. An air inlet pipe (211) and an air suction hole are respectively provided on the upper pressure plate (21). The suction pipe (212) and the air inlet pipe (211) can blow hot air onto the upper surface of the film material (7) through the air inlet hole. The suction pipe (212) can remove the hot air from the upper surface of the film material (7) through the suction hole. The die is provided with a knife hole (221). A knife (23) is slidably arranged in the knife hole (221). The upper end of the knife (23) is used to cut the film material (7) so that a positioning hole is formed on the film material (7). The knife edge can press against the lower end of the template.

5. The vacuum forming apparatus for a lunchbox according to claim 4, characterized in that: The lower end of the cutting tool (23) is connected to the base plate (27) via the mounting base (24), and a first linear module is provided at the lower end of the base plate (27). The first linear module is installed on the lower pressure plate (22) and is used to drive the cutting tool (23) to rise and fall. The mounting base (24) has threads on its periphery and a mounting hole at one end. The tool (23) is a hollow cylindrical structure. The inner diameter of the mounting hole is not greater than the periphery of the tool (23). The tool (23) is installed in the mounting hole, and the cutting edge of one end of the tool (23) is located outside the mounting base (24). The periphery of the mounting base (24) is slidably connected to the tool hole (221). The inner ring of the mounting base (24) is provided with an abutment ring (241). The other end of the tool (23) abuts against the abutment ring (241), and the outer diameter of the tool (23) is greater than the inner diameter of the abutment ring (241). A floating assembly (25) is provided between the mounting base (24) and the base plate (27). The floating assembly (25) includes an upper floating plate (251) and a lower floating plate (252). The upper floating plate (251) is threaded to the periphery of the mounting base (24), and the lower floating plate (252) is connected to the base plate (27). Multiple first sliding rods (253) are provided on the upper floating plate (251), and multiple first sliding holes are provided on the lower floating plate (252). The periphery of the first sliding rods (253) is slidably connected to the first sliding holes, and the lower floating plate (252) is provided with a first clearance hole. The lower periphery of the tool holder is located in the first clearance hole. Multiple hard springs (254) are provided between the upper floating plate (251) and the lower floating plate (252). The multiple hard springs (254) are arranged parallel to each other, and the two ends of each hard spring (254) are fixedly connected to the lower end of the upper floating plate (251) and the upper end of the lower floating plate (252), respectively.

6. The vacuum forming apparatus for a lunchbox according to claim 4, characterized in that: The inner wall of the cutter (23) is a vertical wall. The inner wall of the cutter (23) is a collection structure for the waste material of the membrane material (7) being cut off. The waste material of the membrane material (7) cut off by the cutter can be squeezed and stacked into the inside of the cutter (23). A die is installed at the upper end of the lower pressure plate (22). A floating component (25) is set inside the lower pressure plate (22). A receiving box (26) is slidably set at the bottom of the lower pressure plate (22). The cut membrane material (7) can fall into the receiving box (26). The lower pressure plate (22) is installed on the base plate. A second linear module is set at the lower end of the base plate. The second linear module is fixedly installed on the fixed frame or base.

7. The vacuum forming apparatus for a lunchbox according to claim 6, characterized in that: The first support plate (51) has an L-shaped cross section. The first side of the first support plate (51) is provided with a first elongated hole. A first locking bolt (57) is slidably disposed in the first elongated hole. The outer side of the first locking bolt (57) is threaded to the upper cutting plate (31). The first locking bolt (57) is used to fix the relative position of the first support plate (51) and the upper cutting plate (31). The second side of the first support plate (51) is provided with a second elongated hole. A pressure rod (55) is slidably disposed in the second elongated hole. The outer side of the pressure rod (55) is threaded to a lock nut (58). A lock nut (58) is provided at each end of the second side. The lock nut (58) is used to fix the relative position of the pressure rod (55) and the second side. A U-shaped door panel (59) is provided at one end of the rocker (53). A conveying roller (54) is installed at each end of the U-shaped door panel (59). Each conveying roller (54) is pressed to the side of a membrane material (7), and the two conveying rollers (54) rotate synchronously. A second sliding rod (510) is provided on the U-shaped door panel (59), and a second sliding hole is provided on the first support plate (51). The outer periphery of the second sliding rod (510) is slidably connected to the second sliding hole, and a counterweight (56) is installed at the upper end of the second sliding rod (510).

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