Small-size rigid article packaging machine

Abstract

The invention provides a small-size rigid article packaging machine. The small-size rigid article packaging machine comprises a material conveying device, a thin film unwinding device, a thin film arching and shrinking device, a three-edge heat sealing device, a code spraying device and a cutting device. The article conveying device comprises an annular conveying belt; the thin film unwinding device comprises an unwinding shaft and a guide roller set. A thin film on the unwinding shaft passes through a plurality of guide rollers and then is flatly laid on the annular conveying belt. The thin film arching and shrinking device comprises an arc-shaped guide plate group and a mechanical shrinking mechanism, the thin film which arches and is flatly laid from the two sides to the middle enables the thin film to wrap an object in a U shape, and the arching thin film is tightly pressed on the object; the three-edge heat-sealing device comprises two groups of heat-sealing frames and driving cylinders, and is used for carrying out hot-pressing sealing on film attaching parts on the upper side, the front side and the rear side of an article; the code spraying device is used for spraying codes on packages, and the cutting device comprises a servo cutting knife and a positioning sensor. According to the full-automatic packaging machine, efficient, reliable and used full-automatic packaging of small-size rigid objects is achieved through the unique process of placing, arching and shrinking and then sealing.

Description

Technical Field

[0001] This invention relates to the field of automated packaging machinery technology, specifically to a packaging machine for small-sized rigid items. Background Technology

[0002] Currently, for automated packaging of items within a certain size range, common methods include manual packaging, semi-automatic packaging, or packaging machines using pre-made bags. However, existing technologies have significant shortcomings when packaging small to medium-sized rigid items (such as laboratory test samples, small parts, and small appliance accessories).

[0003] Manual or semi-automatic packaging is inefficient, with each person only able to complete 30-50 packages per hour. Furthermore, packaging consistency is poor, and problems such as film wrinkles and inadequate sealing are common.

[0004] Traditional vertical packaging machines use "film tube making first - material feeding later" as the core process, which is mainly suitable for fluid materials such as granules and powders. For rigid items, jamming and damage from collisions are likely to occur during the feeding process, and the items are not accurately positioned in the film tube, resulting in packaging deviation.

[0005] Pre-made bag packaging machines require pre-made bags of special sizes to be customized in advance, which results in high material costs. Furthermore, when changing the specifications of the items, the pre-made bags must be replaced, which reduces flexibility and makes them unsuitable for packaging needs of multiple varieties and small batches.

[0006] Existing packaging equipment often lacks user-friendly interactive design, and packaged items lack dedicated lifting structures, requiring tools to open. Furthermore, it is difficult to achieve accurate "one item, one code" identification, which is not conducive to product traceability.

[0007] To address the aforementioned issues, there is an urgent need to design an automatic packaging machine that can adapt to small-sized rigid items, has a high degree of automation, and provides excellent packaging results. Summary of the Invention

[0008] This invention provides a packaging machine for small-sized rigid items, which can solve the problems of traditional packaging equipment being unsuitable for rigid items, having low efficiency, and poor packaging consistency, and realize fully automatic sealed packaging of small-sized rigid items.

[0009] To achieve the above objectives, the present invention employs the following technical solution:

[0010] A small-sized rigid item packaging machine includes a material conveying device, a film unwinding device, a film arching and shrinking device, a three-side heat sealing device, and a cutting device. The material conveying device includes an annular conveyor belt. The film unwinding device includes an unwinding shaft and a guide roller assembly. A film roll is mounted on the unwinding shaft, and the guide roller assembly includes multiple guide rollers, with the end guide roller positioned at the front end of the annular conveyor belt. The film on the unwinding shaft passes through the multiple guide rollers and is then laid flat onto the annular conveyor belt. The film arching and shrinking device includes an arc-shaped guide plate assembly and a mechanical shrinking mechanism. The arc-shaped guide plate assembly includes two arc-shaped guide plates positioned above the annular conveyor belt on the left and right sides, used to arch the film from both sides towards the center. The film is laid out in a U-shape to wrap the item; the mechanical shrinking mechanism includes elastic pressing components located at the ends of the left and right arc-shaped guide plates, used to press the arched film onto the item; the three-sided heat sealing device includes two sets of heat sealing frames and drive cylinders, with the two drive cylinders symmetrically arranged on both sides of the annular conveyor belt, and a heat sealing strip set installed at the front end of each drive cylinder, the heat sealing strip set including a U-shaped heat sealing frame composed of three heat sealing strips, used to heat-press and seal the film adhesion points on the top and front and back sides of the item; the cutting device includes a servo cutter and a positioning sensor, when the positioning sensor detects the spatial interval between adjacent packaging strips, the servo cutter cuts at the interval.

[0011] Optionally, it also includes an item input device, which includes a robotic arm for placing items onto a film laid flat on the circular conveyor belt, or a conveying mechanism that docks with an end guide roller at the front end of the circular conveyor belt for conveying items onto the film laid flat on the circular conveyor belt.

[0012] Optionally, the conveying speed of the film is the same as the conveying speed of the annular conveyor belt.

[0013] Optionally, the film unwinding device further includes a tension control mechanism, which includes a telescopic drive, an adjusting roller, and a pressure sensor. The telescopic drive stabilizes the film tension by driving the adjusting roller to move.

[0014] Optionally, a guide positioning piece is provided at the front end of the arc-shaped guide plate to guide the flat film into the arc-shaped guide plate.

[0015] Optionally, the elastic pressing assembly includes a first position sensor, an elastic block, a pressing cylinder, and a first electric push rod. The front end of the elastic block has a groove for adapting to the item, and the rear end is connected to the telescopic end of the pressing cylinder. The fixed end of the pressing cylinder is mounted on the first electric push rod. When the first position sensor detects the item, the pressing cylinder drives the elastic block to extend and press the item so that the film adheres tightly to the item. The first electric push rod extends synchronously, and the extension speed is consistent with the conveying speed of the circular conveyor belt. After a set pressing time, the pressing cylinder retracts and resets, and the first electric push rod retracts and resets.

[0016] Optionally, the groove of the elastic block is composed of a silicone layer, a supporting rigid layer and a heating element, the heating element being used to heat to 60-80°C to slightly soften the film.

[0017] Optionally, the three-sided heat sealing device further includes a second position sensor and second electric push rods disposed on both sides of the annular conveyor belt. Two drive cylinders are respectively mounted on the two electric push rods. When the second position sensor detects that the item has arrived at the heat sealing station, the drive cylinders extend to the two heat sealing strip groups to perform three-sided heat sealing on the item. The second electric push rods extend synchronously, and the extension speed of the second electric push rods is consistent with the conveying speed of the annular conveyor belt. After setting the heat sealing time, the drive cylinders retract and reset, and the second electric push rods retract and reset.

[0018] Optionally, the heat-sealing strip includes a high-temperature resistant pressure block, a heat-sealing resistance wire, and a ceramic base. A temperature sensor is embedded in the heat-sealing strip, and a temperature controller is electrically connected to the temperature sensor and the heat-sealing resistance wire to control the heating of the heat-sealing resistance wire to 180-220°C.

[0019] Optionally, it also includes a cutting device, comprising a top cutting mechanism and a side cutting mechanism. The top cutting mechanism includes a lifting-mouth cutting blade and a top cylinder, the top cylinder being used to drive the lifting-mouth cutting blade to cut a lifting mouth on the film heat-sealed on the top. The side cutting mechanism includes a diamond-shaped cutting blade and a side cylinder, the side cylinder being used to drive the diamond-shaped cutting blade to cut a diamond-shaped tear on the film heat-sealed on the side.

[0020] Optionally, it also includes a coding device, including a coding terminal, an information storage unit, and a third position sensor. When the third position sensor detects that the item has reached the coding position, the coding terminal prints the coding information in the information storage unit onto the surface of the film wrapped around the item.

[0021] Compared with the prior art, the present invention has at least the following advantages:

[0022] Suitable for rigid items: By using the process of "placing the item first - the film arches and shrinks", the feeding jamming problem of traditional vertical packaging machines is avoided, and rigid items with dimensions ≤50cm×30cm×20cm and weight ≤10kg can be packaged stably.

[0023] High degree of automation: From film unwinding and item positioning to cutting and output, the entire process requires no manual intervention. The packaging speed can reach 10-30 pieces / minute, which is 3-6 times more efficient than manual packaging. Moreover, the packaging consistency is good and the sealing qualification rate is ≥99%.

[0024] User-friendly design: The top handle makes it easy to carry items, and the triangular tear-out on the side can be opened without tools, improving ease of use;

[0025] Precise identification and traceability: The inkjet printing mechanism supports printing multiple lines of information that can be changed in real time, achieving "one item, one code", which facilitates product traceability. The inkjet printing is highly clear and can be stored for a long time.

[0026] Highly flexible: Each module can be adjusted according to the size of the item (such as the spacing of the arc guide plate 7 and the width of the limit baffle), adapting to various specifications of items without the need to replace a large number of parts, and the specification change time is ≤10 minutes;

[0027] High stability and safety: Equipped with tension control, temperature control, fault alarm and other functions to reduce packaging failures, and protective cover and anti-slip design to improve operational safety. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the structure of a small-sized rigid item packaging machine according to an embodiment of the present invention. Figure 1 ;

[0030] Figure 2 This is a schematic diagram of the structure of a small-sized rigid item packaging machine according to an embodiment of the present invention. Figure 2 .

[0031] Figure label:

[0032] 1. Conveyor belt; 2. Circular conveyor belt; 3. Unwinding shaft; 4. Guide roller; 5. Telescopic drive component; 6. Adjusting roller; 7. Arc-shaped guide plate; 8. Positioning guide plate; 9. Elastic pressure block; 10. Pressing cylinder; 11. First electric push rod; 12. Heat sealing strip assembly; 13. Drive cylinder; 14. Second electric push rod; 15. Lifting cutter; 16. Diamond cutter; 17. Spraying nozzle; 18. Servo cutter. Detailed Implementation

[0033] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the basic embodiments disclosed below.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0035] like Figure 1-2 As shown, the small-sized rigid item packaging machine of this invention includes a material conveying device, a film unwinding device, a film arching and shrinking device, a three-side heat sealing device, a cutting device, a coding device, and a cutting device.

[0036] The item conveying device is used to transport items to be packaged and packaging film, providing the operational basis for subsequent packaging processes. The item conveying device includes a circular conveyor belt 2, on which, sequentially arranged from front to back, are a film laying and item input station, a film arching and shrinking station, a heat sealing station, a cutting station, a coding station, and a cutting station. Here, the items to be packaged include rigid items with dimensions less than 50cm*30cm*20cm and a weight less than 10kg, such as cylindrical products.

[0037] The film unwinding device is used to feed film onto the circular conveyor belt 2. The film unwinding device includes an unwinding shaft 3 and a guide roller assembly. A film roll is mounted on the unwinding shaft 3. The guide roller assembly includes multiple guide rollers 4, with the end guide roller 4 located at the front end of the circular conveyor belt 2 (i.e., the film laying and item input station). The film on the unwinding shaft 3 passes through the multiple guide rollers 4 and is then laid flat onto the circular conveyor belt 2. The unwinding shaft 3 and the multiple guide rollers 4 are mounted below the circular conveyor belt 2 via a support frame. The unwinding shaft 3 is wound with a film roll formed of PE-PET composite film (or PE film). The film passes around the multiple guide rollers 4 in sequence and finally emerges from the end guide roller 4 and is laid flat onto the circular conveyor belt 2. Here, the end guide roller 4 is located at the front end of the circular conveyor belt 2 and its top is flush with the upper surface of the circular conveyor belt 2. Optionally, the film unwinding device also includes a tension control mechanism, which includes a telescopic drive 5, an adjusting roller 6, and a pressure sensor. The adjusting roller 6 can be one of a plurality of guide rollers 4. The roller frame of the adjusting roller 6 is mounted on the telescopic drive 5. The telescopic drive 5 can be an electric push rod, which can precisely control the displacement of the adjusting roller 6, thereby stabilizing the film tension by driving the adjusting roller 6 to move.

[0038] In practical applications, the items to be packaged can be placed on the front end of the flat film, and the front end of the film can be pressed firmly onto the circular conveyor belt 2. This allows the film released from the unwinding shaft 3 to be smoothly transported along with the circular conveyor belt 2. Then, the items to be packaged can be placed onto the flat film one by one. Here, the film conveying speed is the same as the conveying speed of the circular conveyor belt 2, which can be achieved by linking the drive motor of the unwinding shaft 3 with the drive motor of the circular conveyor belt 2.

[0039] In one optional embodiment, the packaging machine further includes an item input device, which can be a robotic arm for sequentially placing items to be packaged onto a film laid flat on the circular conveyor belt 2; the item input device can also be an item conveying mechanism (e.g., Figure 1 The item conveyor belt is shown in the figure. The item conveying mechanism is connected to the end guide roller 4 at the front end of the circular conveyor belt 2. The item conveying mechanism, the end guide roller 4, and the circular conveyor belt 2 are flush at the top of the connection point, which makes it convenient for the item conveying mechanism to transport the items to be packaged to the film laid flat on the circular conveyor belt 2 via the end guide roller 4.

[0040] The film arching and shrinking device is used to transform the item to be packaged and the flat film into a wrapped shape that tightly adheres to the outer wall of the item, providing a sealing basis for subsequent heat sealing. The film arching and shrinking device includes an arc-shaped guide plate assembly and a mechanical shrinking mechanism. The arc-shaped guide plate assembly includes two arc-shaped guide plates 7 positioned above the annular conveyor belt 2, used to arch the flat film from both sides towards the middle, causing the film to wrap the item in a U-shape. The arc-shaped guide plates 7 are made of 304 stainless steel, with the arc-shaped curved surface facing inwards. The arc-shaped curved surface is mirror-polished to reduce the frictional resistance between the film and the guide plate, preventing scratches or stretching deformation of the film during the arching process. Optionally, guide positioning plates are provided at the front ends (entry ends) of the two arc-shaped guide plates 7 to guide the flat film into the arc-shaped guide plates 7. The positioning guide plate 8 is aligned with the tangent direction of the arc-shaped curved surface of the arc-shaped guide plate 7 and tilted outwards at 5°-10° to guide the flat film smoothly into the arc-shaped guide plate 7, preventing the film from getting stuck or wrinkled at the guide plate entrance.

[0041] The mechanical shrinking mechanism includes elastic pressing components located at the ends of the left and right arc-shaped guide plates 7, used to press the arched film onto the item. The elastic pressing components include a first position sensor, an elastic pressing block 9, a pressing cylinder 10, and a first electric push rod 11. The first position sensor can be a photoelectric position sensor, located at the film shrinking area of ​​the film arching shrinking station, used to detect whether the item to be packaged is in place. The front end of the elastic pressing block 9 has a groove adapted to the item to be packaged, and the rear end is connected to the telescopic end of the pressing cylinder 10. The telescopic direction of the pressing cylinder 10 is perpendicular to the annular conveyor belt 2. The fixed end of the pressing cylinder 10 is located on the first electric push rod 11. The first electric push rod 11 is installed on both sides of the film shrinking area. The first electric push rod 11 is flush with the annular conveyor belt 2, and its extension direction is consistent with the conveying direction of the annular conveyor belt 2, and its extension speed is consistent with the conveying speed of the annular conveyor belt 2. When the first position sensor detects that the item has reached the film shrinkage area, the pressing cylinder 10 drives the elastic pressing block 9 to extend towards the item to be packaged. The grooves of the elastic pressing blocks 9 on both sides press the item so that the film adheres tightly to the item, thereby wrapping the item to be packaged. At the same time, the first electric push rods 11 on both sides extend synchronously. After a set pressing time (e.g., 1s-2s), the pressing cylinder 10 retracts and resets, and then the first electric push rods 11 retract and reset, waiting to shrink and press the film for the next item.

[0042] Optionally, the groove of the elastic pressure block 9 is composed of a silicone layer, a supporting steel layer, and a heating plate. The silicone layer is located on the outermost layer and has elastic protrusions on its surface, which can adapt to the shape of the item and avoid scratching the film during shrinkage. The supporting steel layer has an internal steel core, and the heating plate is located inside the steel core. The heating plate is used to heat the elastic pressure block 9 to 60-80°C, which can slightly soften the film during the shrinkage and pressing process, improve the shrinkage fit, and make the film tightly wrap the item without gaps.

[0043] The three-sided heat sealing device is used to heat seal the top and front and back sides of an item wrapped in film after shrinking and pressing. Here, the left and right sides and bottom of the item are completely wrapped in film, requiring no further heat sealing; three-sided heat sealing is sufficient to completely seal the item. The three-sided heat sealing device includes two sets of heat sealing strips 12, a drive cylinder 13, and a second electric push rod 14. The two electric push rods are symmetrically positioned on both sides of the heat sealing station, parallel to the annular conveyor belt 2, and their travel direction and extension speed are consistent with the conveying direction and speed of the annular conveyor belt 2. The rear ends of the two drive cylinders 13 are connected to the two electric push rods, and the drive cylinders 13 are perpendicular to the annular conveyor belt 2. The heat sealing strips 12 are installed at the extension and retraction ends of the drive cylinders 13. The heat sealing strips 12 include a U-shaped heat sealing frame composed of three heat sealing strips 12, used for heat-press sealing of the film adhesion points on the top and front and back sides of the item. Optionally, a second position sensor is also provided on both sides of the heat sealing station to detect whether the item wrapped in the compressed film is in place. When the second position sensor detects that the item is in place, the two drive cylinders 13 extend towards the item on the annular conveyor belt 2 and bring it to the two heat sealing strip groups 12 to perform three-sided heat sealing on the item. At the same time, the two second electric push rods 14 extend synchronously. After setting the heat sealing time (e.g., 1s-2s), the drive cylinders 13 retract and reset, and then the second electric push rods 14 retract and reset.

[0044] Optionally, the heat-sealing strip includes a high-temperature resistant pressure block, a heat-sealing resistance wire, and a ceramic base. A temperature sensor is embedded in the heat-sealing strip, and a temperature controller is electrically connected to the temperature sensor and the heat-sealing resistance wire. Here, the high-temperature resistant pressure block is located at the front end of the heat-sealing strip, the heat-sealing resistance wire and the temperature sensor are embedded in the high-temperature resistant pressure block, and the ceramic base is located at the rear end of the heat-sealing strip. The drive cylinder 13 is connected to the heat-sealing strip via the ceramic base. The high-temperature resistant pressure block is made of polytetrafluoroethylene (PTFE) material with a smooth surface, which can prevent the film from sticking during the heat-sealing process. The temperature controller uses a PID temperature control method to control the heat-sealing resistance wire to heat the heat-sealing strip to 180-220℃, which can melt the film. The drive cylinder 13 controls the pressure of the high-temperature resistant pressure block on the film by adjusting the air pressure, with an air pressure range of 0.2-0.5MPa. During heat sealing, the heat-sealing strip group 12 on both sides presses the film and melts it. After the heat-sealing time, the heat-sealing strip group 12 retracts, and the molten film cools and solidifies, forming a sealed three-sided heat-sealing structure that meets the requirements for waterproofing and dustproofing.

[0045] The cutting device is used to cut a lifting opening and a tear opening on the heat-sealed area of ​​the upper edge and one side edge of the film of an item, respectively. The cutting device includes a top cutting mechanism and a side cutting mechanism. The top cutting mechanism includes a lifting opening cutting blade 15 and a top cylinder. The top cylinder is used to drive the lifting opening cutting blade 15 to cut a lifting opening (the lifting opening can be a rounded square opening, about 18mm high and about 10cm long) on ​​the heat-sealed film. The side cutting mechanism includes a diamond-shaped cutting blade 16 and a side cylinder. The side cylinder is used to drive the diamond-shaped cutting blade 16 to cut a diamond-shaped tear opening on the heat-sealed film. Here, the cutting device also includes a position sensor to detect whether the heat-sealed item has been conveyed to the cutting station. When the item arrives, the top cylinder drives the lifting cutter 15 to extend towards the upper heat-sealed area of ​​the film for cutting. Then, the side cylinder drives the diamond-shaped cutter 16 to extend towards the side heat-sealed area of ​​the film for cutting, creating a lifting opening for easy handling of the packaged item and a diamond-shaped tear for easy opening of the packaging. It should be noted that the side cylinder and the diamond-shaped cutter 16 are aligned with the side heat-sealed area, and the width of the diamond-shaped cutter 16 is less than the width of the heat-sealed area. That is, the diamond-shaped tear does not extend beyond the heat-sealed film and will not affect the product's seal. Furthermore, this diamond-shaped tear is the cutting point of the subsequent cutting device, and the diamond-shaped tear forms a triangular tear on two adjacent packages.

[0046] The coding device includes a coding terminal 17, an information storage unit, and a third position sensor. The information storage unit stores coding information such as production date, batch number, specifications, and traceability code. The third position sensor detects whether the packaged item has been delivered to the coding station. When the third position sensor detects that the item has reached the coding position, the coding terminal 17 prints the coding information from the information storage unit onto the surface of the film wrapping the item. Here, the coding terminal 17 is a piezoelectric coding terminal, supporting rapid printing of multiple lines of characters while ensuring coding clarity. The coding range of the coding terminal 17 is adjustable, for example, 30mm*15mm*15mm. It should be noted that the information storage unit can also have a built-in control unit, which sequentially switches the coding information for each package according to the pre-stored coding information library, achieving one item, one code.

[0047] The cutting device is used to cut continuous packaging into individual packages. It includes a servo cutter 18 and a positioning sensor (which may be a fiber optic sensor). When the positioning sensor detects a spatial gap (diamond-shaped tear) between adjacent packaging strips, the servo cutter 18 cuts at the gap. The servo cutter 18 is also covered with a transparent protective cover.

[0048] According to an exemplary embodiment of the present invention, the small-sized rigid item packaging machine further includes a control system, which is electrically connected to each device and is used to control the timing of each device, including the drive control of the annular conveyor belt 2, the unwinding shaft 3, and each cylinder and electric push rod, to ensure the continuity and automation of item packaging.

[0049] In practical application scenarios, the conveyor belt, film roll, cylinder, electric push rod, position sensor, spray nozzle 17, cutting blade and other components of the small-sized rigid item packaging machine of the present invention can all adopt the corresponding equipment or devices in the prior art; the arc guide plate 7, elastic pressure block 9, heat sealing strip, cutting blade and other components can all be made of relevant materials in the prior art according to the size, shape and other requirements in the actual working conditions.

[0050] Furthermore, other equipment or components can be installed in this small-sized rigid item packaging machine, or the actual installation positions of each piece of equipment or component can be adjusted to realize the actual application or other functions of the packaging machine.

[0051] It should be noted that, depending on the implementation needs, the various components described in the embodiments of the present invention can be split into more components, or two or more components or parts of components can be combined into new components to achieve the purpose of the embodiments of the present invention.

[0052] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A small-sized rigid item packaging machine, characterized in that, Includes a material conveying device, a film unwinding device, a film arching and shrinking device, a three-side heat sealing device, and a cutting device; The item conveying device includes a circular conveyor belt; The film unwinding device includes an unwinding shaft and a guide roller assembly. A film roll is mounted on the unwinding shaft, and the guide roller assembly includes multiple guide rollers with the end guide roller located at the front end of the annular conveyor belt. The film on the unwinding shaft is laid flat onto the annular conveyor belt after passing through the multiple guide rollers. The film arching and shrinking device includes an arc-shaped guide plate assembly and a mechanical shrinking mechanism. The arc-shaped guide plate assembly includes two arc-shaped guide plates on the left and right sides, which are arranged above the circular conveyor belt to arch the flat film from both sides to the middle so that the film wraps the item in a U-shape. The mechanical shrinking mechanism includes elastic pressing components arranged at the ends of the left and right arc-shaped guide plates to press the arched film onto the item. The three-sided heat sealing device includes two sets of heat sealing strips and a drive cylinder. The two drive cylinders are symmetrically arranged on both sides of the annular conveyor belt. Each drive cylinder has a heat sealing strip set installed at its front end. The heat sealing strip set includes a U-shaped heat sealing frame composed of three heat sealing strips, which is used to heat-press and seal the film bonding area on the upper and front sides of the item. The cutting device includes a servo cutter and a positioning sensor. When the positioning sensor detects a spatial gap between adjacent packaging strips, the servo cutter cuts at the gap.

2. The small-sized rigid item packaging machine according to claim 1, characterized in that, The conveying speed of the film is the same as the conveying speed of the annular conveyor belt.

3. The small-sized rigid item packaging machine according to claim 1, characterized in that, The film unwinding device also includes a tension control mechanism, which includes a telescopic drive, an adjusting roller, and a pressure sensor. The telescopic drive stabilizes the film tension by driving the adjusting roller to move.

4. A small-sized rigid item packaging machine according to claim 1, characterized in that, The front end of the arc-shaped guide plate is provided with a guide positioning piece to guide the flat film into the arc-shaped guide plate.

5. A small-sized rigid item packaging machine according to claim 1, characterized in that, The elastic clamping assembly includes a first position sensor, an elastic block, a clamping cylinder, and a first electric push rod. The front end of the elastic block has a groove for adapting to the item, and the rear end is connected to the telescopic end of the clamping cylinder. The fixed end of the clamping cylinder is set on the first electric push rod. When the first position sensor detects an item, the clamping cylinder drives the elastic block to extend and press the item so that the film adheres tightly to the item. The first electric push rod extends synchronously and the extension speed is consistent with the conveying speed of the circular conveyor belt. After setting the clamping time, the clamping cylinder retracts and resets, and the first electric push rod retracts and resets.

6. A small-sized rigid item packaging machine according to claim 6, characterized in that, The groove of the elastic pressure block is composed of a silicone layer, a supporting steel layer and a heating element. The heating element is used to heat to 60-80°C to slightly soften the film.

7. A small-sized rigid item packaging machine according to claim 1, characterized in that, The three-sided heat sealing device also includes a second position sensor and a second electric push rod disposed on both sides of the annular conveyor belt, with two drive cylinders respectively mounted on the two electric push rods; When the second position sensor detects that the item has arrived at the heat sealing station, the drive cylinder extends to the two heat sealing strip groups to perform three-sided heat sealing on the item. The second electric push rod extends synchronously, and the extension speed of the second electric push rod is consistent with the conveying speed of the circular conveyor belt. After setting the heat sealing time, the drive cylinder retracts and resets, and the second electric push rod retracts and resets.

8. A small-sized rigid item packaging machine according to claim 1, characterized in that, The heat-sealing strip includes a high-temperature resistant pressure block, a heat-sealing resistance wire, and a ceramic base. A temperature sensor is embedded in the heat-sealing strip, and a temperature controller is electrically connected to the temperature sensor and the heat-sealing resistance wire to control the heating of the heat-sealing resistance wire to 180-220℃.

9. A small-sized rigid item packaging machine according to claim 1, characterized in that, It also includes a cutting device, comprising a top cutting mechanism and a side cutting mechanism. The top cutting mechanism includes a lifting cutting blade and a top cylinder, the top cylinder being used to drive the lifting cutting blade to cut a lifting opening on the film that is heat-sealed and pressed on the top. The side cutting mechanism includes a diamond-shaped cutting blade and a side cylinder, the side cylinder being used to drive the diamond-shaped cutting blade to cut a diamond-shaped tear on the film that is heat-sealed and pressed on the side.

10. A small-sized rigid article packaging machine according to any one of claims 1-9, characterized in that, It also includes a coding device, including a coding terminal, an information storage unit, and a third position sensor. When the third position sensor detects that the item has reached the coding position, the coding terminal prints the coding information in the information storage unit onto the surface of the film wrapped around the item.

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