CN112572866A

CN112572866A - Plastic packaging equipment for packaging boxes of nourishing products

Info

Publication number: CN112572866A
Application number: CN202011549779.4A
Authority: CN
Inventors: 林嘉珣
Original assignee: Dazhou Xinyan Xiamen Biological Technology Co ltd
Current assignee: Dazhou Xinyan Xiamen Biological Technology Co ltd
Priority date: 2020-12-24
Filing date: 2020-12-24
Publication date: 2021-03-30

Abstract

The invention discloses plastic packaging equipment for a packaging box of a nourishing product, which comprises a rack, a film discharging device, a film folding device, a cutting device and two conveying devices, wherein the film discharging device is arranged on the rack; the film discharging device is arranged on one side of the rack, and the folded roll-shaped plastic film is arranged on the film discharging device; after the plastic film enters the film folding device, the opposite folding edges of the plastic film are folded inwards to clamp the opposite folding edges at the free ends between the upper layer and the lower layer of the plastic film; the film folding device comprises two film folding plates and a lifting device; the lower film folding plate is fixed on the rack, and the upper film folding plate is fixed on the rack through a lifting device; the conveying device is arranged between the two film folding plates in a penetrating mode; one side of the film folding plate close to the feeding end of the conveying device is a forming bevel edge; the forming bevel edges of the two film folding plates are respectively embedded into the inward folding bevel edges on the upper side and the lower side of the plastic film; the cutting device is arranged at the discharge end of the film folding device, and the adjacent edges of the plastic film are sealed and cut through the cutting device.

Description

Plastic packaging equipment for packaging boxes of nourishing products

Technical Field

The invention relates to the technical field of packaging equipment, in particular to plastic packaging equipment for a packaging box of a nourishing product.

Background

With the development of society and the continuous improvement of people's living standard, the nourishing product is gradually favored by people. In the production process, a plastic film is often required to be packaged outside the packaging box to protect the packaging box from being wetted or worn. The existing plastic packaging equipment for the nourishing product packaging box is complex in structure, the phenomenon of clamping bands is easily generated in the process of conveying plastic films and plastic packaging, and the plastic packaging needs to be carried out for multiple times for the same packaging box, so that the plastic packaging process is unstable, the production efficiency is reduced, and the production cost of enterprises is improved.

Disclosure of Invention

The invention aims to provide plastic packaging equipment for a packaging box of a nourishing product, which can continuously discharge plastic films and wrap the packaging box by pulling the free end of the plastic film through a conveying device corresponding to a cutting device, and then seal and cut the adjacent edges of the plastic films through the cutting device.

In order to achieve the purpose, the invention adopts the following technical scheme:

a plastic packaging device for a packaging box of a nourishing product comprises a rack, a film discharging device, a film folding device, a cutting device and two conveying devices, wherein the two conveying devices respectively correspond to the film folding device and the cutting device; the film discharging device is arranged on one side of the rack, and the folded roll-shaped plastic film is arranged on the film discharging device; after the free end of the plastic film enters the film folding device, the opposite folding edges of the plastic film are folded inwards to clamp the opposite folding edges of the free end between the upper layer and the lower layer of the plastic film; the film folding device comprises two film folding plates and a lifting device, wherein the two film folding plates are arranged oppositely up and down; one end of the lower film folding plate, which is far away from the film discharging device, is fixed on the rack, and the upper film folding plate is fixed on the rack through a lifting device; the conveying device corresponding to the film folding device penetrates between the two film folding plates, and the packaging box is conveyed through the conveying device; one side of the film folding plate close to the feeding end of the conveying device is a forming bevel edge; the forming bevel edges of the two film folding plates are respectively embedded into the inward folding bevel edges on the upper side and the lower side of the plastic film, the plastic film is pulled by a conveying device corresponding to the cutting device to be discharged, and the plastic film is coated outside the packaging box; the cutting device is arranged at the discharge end of the film folding device, and the adjacent edges of the plastic film are sealed and cut through the cutting device.

Furthermore, the cutting device comprises a fixed cutter bar, a heating device, a movable cutter bar, a mounting frame and a driving device; the fixed cutter bar and the movable cutter bar are both L-shaped; the fixed cutter bars are fixed at the feed end and one side of the conveying device corresponding to the cutting device; the heating device is connected with the fixed cutter bar and heats the fixed cutter bar through the heating device; the mounting frame is rotatably connected with the upper end of the rack through a mounting seat; the movable cutter bar is arranged at the lower end of the mounting frame through a plurality of connecting pieces; the driving device drives the mounting frame to swing back and forth to close or open the movable cutter strip and the fixed cutter strip so as to carry out sealed cutting on the plastic film coated outside the packaging box.

Further, the connecting piece comprises a connecting screw rod and two connecting nuts; the lower end of the connecting screw is fixedly connected with the movable cutter bar, the upper end of the connecting screw penetrates through the mounting frame, and the connecting nuts are respectively arranged on the connecting screws on two sides of the mounting frame.

Furthermore, the lifting device comprises a lifting plate, a lifting screw rod, a fixed block and at least two guide posts; the lower end of the guide post is fixedly connected with the rack, and the upper end of the guide post is fixedly connected with the fixed block; the lifting screw rod is rotationally connected with the fixed block; one end of the lifting plate is fixedly connected with the upper film folding plate, and the other end of the lifting plate is sleeved on the guide post; the lifting screw rod is in threaded connection with the lifting plate, and the mounting height of the upper diaphragm folding plate is adjusted by rotating a hand wheel on the lifting screw rod.

Furthermore, a support rod is arranged at the lower end of the lifting plate; one end of the support rod, which is far away from the film discharging device, is fixedly connected with the lifting plate, and the upper plastic film penetrates through the lifting plate and the support rod.

Further, the film discharging device comprises two side plates, two supporting rollers and a guide roller; the end parts of the supporting rollers are respectively rotatably connected with the side plates, and the coiled plastic film is placed between the two supporting rollers; the guide roller is rotatably arranged on a side plate on one side of the film folding device, and the free end of the plastic film enters the film folding device after being wound on the guide roller; limiting devices are respectively arranged on two sides of the plastic film; the limiting device comprises a baffle and a limiting bolt; the inner end of the limiting bolt is fixedly connected with the baffle, the outer end of the limiting bolt is in threaded connection with the side plate, and the distance between the baffle and the end part of the rolled plastic film is adjusted by rotating the limiting bolt.

Further, the conveying device comprises a driving motor, a driving roller, a driven roller and a conveying belt, wherein the driving motor, the driving roller, the driven roller and the conveying belt are fixed on the rack; the driving roller and the driven roller are rotationally connected with the rack; the conveying belt is sleeved on the driving roller and the driven roller; and an output shaft of the driving motor is fixedly connected with the driving roller.

Further, the mounting seat comprises a mounting block, a rotating shaft and a mounting bolt; the mounting block is provided with a mounting chute along the direction perpendicular to the transmission direction of the conveying device, and a mounting bolt penetrates through the mounting chute to be in threaded connection with the rack so as to lock the mounting block on the rack; one end of the rotating shaft is rotatably connected with the mounting block, and the other end of the rotating shaft is fixedly connected with the mounting frame.

Further, a collecting device for collecting residual plastic films is arranged on the machine frame; the collecting device comprises a collecting motor, a belt collecting wheel and a belt guide roller; the collecting motor is fixed on the rack, and the tape guide roller is rotationally arranged on the rack; the take-up pulley is fixed on an output shaft of the collecting motor, and the residual plastic film bypasses the tape guide roller and is wound on the take-up pulley.

Furthermore, the driving device comprises a sealing and cutting motor, a swing rod and a connecting rod; the sealing and cutting motor is fixed on the frame; one end of the swing rod is fixedly connected with the side wall of an output shaft of the seal cutting motor, and the other end of the swing rod is hinged with the lower end of the connecting rod; the upper end of the connecting rod is hinged with the mounting frame, and the movable cutter strip and the fixed cutter strip are driven to close or open in a reciprocating mode through the sealing and cutting motor.

After the technical scheme is adopted, the invention has the following beneficial effects:

1. according to the plastic packaging equipment for the packaging box of the nourishing product, the free end of the plastic film is pulled through the conveying device corresponding to the cutting device, so that the plastic film can be continuously discharged and coated outside the packaging box, and then the adjacent edges of the plastic film are sealed and cut through the cutting device.

2. According to the plastic packaging equipment for the nourishing product packaging box, the mounting frame is driven to swing in a reciprocating mode through the driving device, the movable cutter strip and the fixed cutter strip are closed or opened, the adjacent edges of the plastic film coated outside the packaging box are sealed and cut, the mounting height of the movable cutter strip can be adjusted according to the connecting nut, and the operation is simple and convenient.

3. According to the plastic packaging equipment for the nourishing product packaging boxes, the mounting height of the upper film folding plate can be adjusted by rotating the lifting screw rod, the plastic packaging equipment is suitable for plastic packaging of packaging boxes with different heights, the flexibility is good, and the supporting rod is convenient for supporting the upper plastic film, so that the packaging boxes are clamped between the upper plastic film and the lower plastic film under conveying of the conveying belt.

4. According to the plastic packaging equipment for the nourishing product packaging box, the rolled plastic film is placed between the two supporting rollers, the rolled plastic film can be driven to rotate for discharging when the free end of the plastic film is pulled, and the rolled plastic film enters the film folding device after being wound on the guide roller, so that the phenomenon of tape jamming is not easily caused; still through the interval of rotatory spacing bolt adjustable baffle and roll-shaped plastic film tip, can effectively hinder roll-shaped plastic film to take place the side and move, and applicable in the plastic film of different width spacing, the flexibility is good.

5. According to the plastic packaging equipment for the nourishing product packaging box, the collection motor drives the take-up pulley to rotate, the cut residual plastic film can be wound, the residual plastic film is not easy to wind the equipment, and the residual plastic film is treated in a centralized manner.

6. According to the plastic packaging equipment for the nourishing product packaging box, the movable cutter strip and the fixed cutter strip are driven to close or open by the reciprocating motion of the sealing and cutting motor, so that the adjacent edges of the plastic film can be cut continuously, and the sealing and cutting efficiency can be improved.

Drawings

FIG. 1 is a schematic perspective view of the present invention;

FIG. 2 is a schematic perspective view of the film discharging device, the conveying device and the film folding device of the present invention;

FIG. 3 is a schematic perspective view of the film discharging device and the film folding device of the present invention without a conveying device;

FIG. 4 is a schematic perspective view of the spacing device of the present invention;

FIG. 5 is a schematic structural view of a folded plastic film and a sealing position according to the present invention;

FIG. 6 is a schematic view of the plastic film of the present invention after it is unfolded at the fold;

FIG. 7 is a schematic perspective view of the cutting device, the conveying device and the collecting device of the present invention;

fig. 8 is a schematic perspective view of the cutting device, the conveying device and the collecting device of the present invention without a front end frame.

The reference numbers in the figures denote:

1. a frame; 2. a film discharging device; 20. a side plate; 21. a support roller; 22. a guide roller; 23. a limiting device; 230. a baffle plate; 231. a limit bolt; 3. a conveying device; 30. a drive motor; 31. a drive roll; 32. a driven roller; 33. a conveyor belt; 4. a film folding device; 40. a membrane folding plate; 400. forming a bevel edge; 41. a lifting device; 410. a lifting plate; 411. a lifting screw rod; 412. a fixed block; 413. a guide post; 414. a hand wheel; 42. a support bar; 5. a plastic film; 50. folding edges; 51. an inflected bevel edge; 6. packaging boxes; 7. a cutting device; 70. fixing the cutter bar; 71. a heating device; 72. a movable blade; 73. installing a frame; 74. a drive device; 740. sealing and cutting the motor; 741. a swing rod; 742. a connecting rod; 75. a mounting seat; 750. mounting blocks; 7500. installing a chute; 751. a rotating shaft; 752. installing a bolt; 76. a connecting member; 760. connecting a screw rod; 761. a connecting nut; 8. a collection device; 80. collecting the motor; 81. a belt retracting wheel; 82. and a tape guide roller.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 1 to 8, a plastic packaging apparatus for a packaging box of a nourishing product includes a frame 1, a film discharging device 2, a film folding device 4, a cutting device 7, and two conveying devices 3 corresponding to the film folding device 4 and the cutting device 7, respectively; the film discharging device 2 is arranged on one side of the rack 1, and the folded roll-shaped plastic film 5 is arranged on the film discharging device 2; after the free end of the plastic film 5 enters the film folding device 4, the opposite folding edges 50 of the plastic film 5 are folded inwards to clamp the opposite folding edges 50 of the free end between the upper and lower layers of the plastic films 5; the film folding device 4 comprises two film folding plates 40 and a lifting device 41 which are arranged oppositely up and down; one end of the lower film folding plate 40, which is far away from the film discharging device 2, is fixed on the rack 1, and the upper film folding plate 40 is fixed on the rack 1 through a lifting device 41; the conveying device 3 corresponding to the film folding device 4 is arranged between the two film folding plates 40 in a penetrating mode, and the packaging box 6 is conveyed through the conveying device 3; one side of the film folding plate 40 close to the feeding end of the conveying device 3 is a forming bevel edge 400; the forming bevel edges 400 of the two film folding plates 40 are respectively embedded into the inward-folding bevel edges 51 on the upper side and the lower side of the plastic film 5, the plastic film 5 is pulled by the conveying device 3 corresponding to the cutting device 7 to discharge materials, and the plastic film 5 is coated outside the packaging box 6; the cutting device 7 is arranged at the discharge end of the film folding device 4, and the adjacent edges of the plastic film 5 are sealed and cut through the cutting device 7.

As shown in fig. 1, 7 and 8, the cutting device 7 includes a fixed blade bar 70, a heating device 71, a movable blade bar 72, a mounting frame 73 and a driving device 74; the fixed cutter bar 70 and the movable cutter bar 72 are both L-shaped; the fixed cutter bars 70 are fixed at the feed end and one side of the conveying device 3 corresponding to the cutting device 7; the heating device 71 is connected with the fixed cutter bar 70, and the fixed cutter bar 70 is heated by the heating device 71; the mounting frame 73 is rotatably connected with the upper end of the frame 1 through a mounting seat 75; the movable cutter bars 72 are arranged at the lower end of the mounting frame 73 through a plurality of connecting pieces 76; the driving device 74 drives the mounting frame 73 to swing back and forth to close or open the movable cutter bar 72 and the fixed cutter bar 70 so as to seal and cut the plastic film 5 coated outside the packaging box 6.

As shown in fig. 1, 7 and 8, the connecting member 76 includes a connecting screw 760 and two connecting nuts 761; the lower end of the connecting screw 760 is fixedly connected with the movable blade bar 72, the upper end of the connecting screw 760 penetrates through the mounting frame 73, and the connecting nuts 761 are respectively arranged on the connecting screws 760 at two sides of the mounting frame 73.

As shown in fig. 1 to 3, the lifting device 41 includes a lifting plate 410, a lifting screw 411, a fixing block 412 and at least two guide posts 413; the lower end of the guide column 413 is fixedly connected with the frame 1, and the upper end of the guide column 413 is fixedly connected with the fixed block 412; the lifting screw rod 411 is rotatably connected with the fixed block 412; one end of the lifting plate 410 is fixedly connected with the upper film folding plate 40, and the other end of the lifting plate 410 is sleeved on the guide post 413; the lifting screw 411 is in threaded connection with the lifting plate 410, and the installation height of the upper diaphragm folding plate 40 is adjusted by rotating a hand wheel 414 on the lifting screw 411.

As shown in fig. 1 to 3, a support rod 42 is disposed at the lower end of the lifting plate 410; one end of the support rod 42, which is far away from the film discharging device 2, is fixedly connected with the lifting plate 410, and the upper plastic film 5 is arranged between the lifting plate 410 and the support rod 42 in a penetrating manner.

As shown in fig. 1 to 3, the film discharging device 2 includes two side plates 20, two supporting rollers 21 and a guiding roller 22; the end parts of the supporting rollers 21 are respectively connected with the side plates 20 in a rotating way, and the rolled plastic film 5 is placed between the two supporting rollers 21; the guide roller 22 is rotatably arranged on the side plate 20 on one side of the film folding device 4, and the free end of the plastic film 5 is wound on the guide roller 22 and then enters the film folding device 4; two sides of the plastic film 5 are respectively provided with a limiting device 23; the limiting device 23 comprises a baffle plate 230 and a limiting bolt 231; the inner end of the limiting bolt 231 is fixedly connected with the baffle plate 230, the outer end of the limiting bolt 231 is in threaded connection with the side plate 20, and the distance between the baffle plate 230 and the end part of the rolled plastic film 5 is adjusted by rotating the limiting bolt 231.

As shown in fig. 1, 2, 7 and 8, the conveying device 3 includes a driving motor 30, a driving roller 31, a driven roller 32 and a conveying belt 33 fixed on the frame 1; the driving roller 31 and the driven roller 32 are rotationally connected with the frame 1; the conveying belt 33 is sleeved on the driving roller 31 and the driven roller 32; an output shaft of the driving motor 30 is fixedly connected with the driving roller 31.

As shown in fig. 1, 7 and 8, the mounting base 75 includes a mounting block 750, a rotation shaft 751 and a mounting bolt 752; the mounting block 750 is provided with a mounting chute 7500 along the direction perpendicular to the transmission direction of the conveying device 3, and a mounting bolt 752 passes through the mounting chute 7500 to be in threaded connection with the rack 1 so as to lock the mounting block 750 on the rack 1; one end of the rotating shaft 751 is rotatably connected with the mounting block 750, and the other end of the rotating shaft 751 is fixedly connected with the mounting frame 73.

As shown in fig. 1, 7 and 8, the frame 1 is provided with a collecting device 8 for collecting the residual plastic film 5; the collecting device 8 comprises a collecting motor 80, a belt collecting wheel 81 and a belt guide roller 82; the collecting motor 80 is fixed on the frame 1, and the tape guide roller 82 is rotatably arranged on the frame 1; the take-up pulley 81 is fixed on the output shaft of the collection motor 80, and the residual plastic film 5 is wound on the take-up pulley 81 by bypassing the tape guide roller 82.

As shown in fig. 1, 7 and 8, the driving device 74 includes a sealing and cutting motor 740, a swing link 741 and a link 742; the sealing and cutting motor 740 is fixed on the frame 1; one end of the swing rod 741 is fixedly connected with the side wall of the output shaft of the sealing and cutting motor 740, and the other end of the swing rod 741 is hinged with the lower end of the connecting rod 742; the upper end of the connecting rod 742 is hinged with the mounting frame 73, and the movable knife strip 72 and the fixed knife strip 70 are driven to close or open in a reciprocating mode through the sealing and cutting motor 740.

The working principle of the invention is as follows:

when the plastic packaging equipment for the nourishing product packaging box is used, firstly, the folded roll-shaped plastic film 5 is placed between the two supporting rollers 21, the free end of the plastic film 5 is wound on the guide roller 22 and then enters the film folding device 4, and when the free end of the plastic film 5 is pulled, the roll-shaped plastic film 5 on the two supporting rollers 21 can rotate to discharge; then, after the free end of the plastic film 5 enters the film folding device 4, the plastic film 5 can be folded and supported by the film folding device 4, so that the upper and lower layers of the plastic film 5 after being folded are respectively positioned at the upper and lower sides of the conveying device 3 corresponding to the film folding device 4, and at the moment, the packaging box 6 enters the space between the two film folding plates 40 under the driving of the conveying device 3 and is coated by the upper and lower layers of the plastic film 5; then, the lower layer of plastic film 5 penetrates out of the gap between the adjacent conveying devices 3, the lower layer of plastic film 5 is positioned above the fixed cutter bar 70, the lower layer of plastic film 5 is positioned above the conveying device 3 corresponding to the cutting device 7, and the conveying device 3 can pull the plastic film 5 to discharge and convey the packaging box 6 coated with the plastic film 5; finally, when the plastic film 5 coated outside the packaging box 6 enters the cutting device 7, the sealing and cutting motor 740 is rotated to drive the movable knife strip 72 to press down, the upper and lower plastic films 5 coated outside the packaging box 6 are attached together by the pressed movable knife strip 72, and when the movable knife strip 72 and the heated fixed knife strip 70 are closed, the plastic film 5 is fused at the closed position of the movable knife strip 72 and the fixed knife strip 70, so that the sealed cutting of the adjacent edges of the plastic film 5 is realized, the collecting motor 80 can drive the collecting wheel 81 to rotate, and the cut residual plastic film 5 is wound.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. The utility model provides a nourish product packaging box plastic envelope equipment which characterized in that: comprises a frame (1), a film discharging device (2), a film folding device (4), a cutting device (7) and two conveying devices (3) which respectively correspond to the film folding device (4) and the cutting device (7); the film discharging device (2) is arranged on one side of the rack (1), and the folded roll-shaped plastic film (5) is arranged on the film discharging device (2); after the free end of the plastic film (5) enters the film folding device (4), the opposite folding edges (50) of the plastic film (5) are folded inwards to clamp the opposite folding edges (50) of the free end between the plastic films (5) of the upper layer and the lower layer; the film folding device (4) comprises two film folding plates (40) and a lifting device (41), wherein the two film folding plates are arranged oppositely up and down; one end, far away from the film discharging device (2), of the lower film folding plate (40) is fixed on the rack (1), and the upper film folding plate (40) is fixed on the rack (1) through a lifting device (41); the conveying device (3) corresponding to the film folding device (4) is arranged between the two film folding plates (40) in a penetrating mode, and the packaging box (6) is conveyed through the conveying device (3); one side of the film folding plate (40) close to the feeding end of the conveying device (3) is a forming bevel edge (400); the forming bevel edges (400) of the two film folding plates (40) are respectively embedded into the inward folding bevel edges (51) on the upper side and the lower side of the plastic film (5), the plastic film (5) is pulled to discharge materials through the conveying device (3) corresponding to the cutting device (7), and the plastic film (5) is coated outside the packaging box (6); the cutting device (7) is arranged at the discharge end of the film folding device (4), and the adjacent edges of the plastic film (5) are sealed and cut through the cutting device (7).

2. The plastic packaging device for the nourishing product packaging box according to claim 1, wherein: the cutting device (7) comprises a fixed cutter bar (70), a heating device (71), a movable cutter bar (72), an installation frame (73) and a driving device (74); the fixed cutter bar (70) and the movable cutter bar (72) are both L-shaped; the fixed cutter bars (70) are fixed at the feed end and one side of the conveying device (3) corresponding to the cutting device (7); the heating device (71) is connected with the fixed cutter bar (70), and the fixed cutter bar (70) is heated through the heating device (71); the mounting frame (73) is rotatably connected with the upper end of the rack (1) through a mounting seat (75); the movable cutter bar (72) is arranged at the lower end of the mounting frame (73) through a plurality of connecting pieces (76); the driving device (74) drives the mounting frame (73) to swing back and forth to close or open the movable cutter strip (72) and the fixed cutter strip (70) so as to seal and cut the plastic film (5) coated outside the packaging box (6).

3. The plastic packaging device for the nourishing product packaging box according to claim 2, wherein: the connecting piece (76) comprises a connecting screw (760) and two connecting nuts (761); the lower end of the connecting screw rod (760) is fixedly connected with the movable cutter bar (72), the upper end of the connecting screw rod (760) penetrates through the installation frame (73), and the connecting nuts (761) are respectively arranged on the connecting screw rods (760) on two sides of the installation frame (73).

4. The plastic packaging device for the nourishing product packaging box according to claim 1, wherein: the lifting device (41) comprises a lifting plate (410), a lifting screw rod (411), a fixed block (412) and at least two guide columns (413); the lower end of the guide post (413) is fixedly connected with the rack (1), and the upper end of the guide post (413) is fixedly connected with the fixed block (412); the lifting screw rod (411) is rotatably connected with the fixed block (412); one end of the lifting plate (410) is fixedly connected with the upper film folding plate (40), and the other end of the lifting plate (410) is sleeved on the guide column (413); the lifting screw rod (411) is in threaded connection with the lifting plate (410), and the installation height of the upper diaphragm folding plate (40) is adjusted by rotating a hand wheel (414) on the lifting screw rod (411).

5. The plastic packaging device for the nourishing product packaging box according to claim 4, wherein: the lower end of the lifting plate (410) is provided with a support rod (42); one end of the support rod (42) far away from the film discharging device (2) is fixedly connected with the lifting plate (410), and the upper layer of plastic film (5) penetrates between the lifting plate (410) and the support rod (42).

6. The plastic packaging device for the nourishing product packaging box according to claim 1, wherein: the film discharging device (2) comprises two side plates (20), two supporting rollers (21) and a guide roller (22); the end parts of the supporting rollers (21) are respectively rotatably connected with the side plates (20), and the rolled plastic film (5) is placed between the two supporting rollers (21); the guide roller (22) is rotatably arranged on the side plate (20) on one side of the film folding device (4), and the free end of the plastic film (5) is wound on the guide roller (22) and then enters the film folding device (4); two sides of the plastic film (5) are respectively provided with a limiting device (23); the limiting device (23) comprises a baffle plate (230) and a limiting bolt (231); the inner end of the limiting bolt (231) is fixedly connected with the baffle plate (230), the outer end of the limiting bolt (231) is in threaded connection with the side plate (20), and the distance between the baffle plate (230) and the end part of the rolled plastic film (5) is adjusted by rotating the limiting bolt (231).

7. The plastic packaging device for the nourishing product packaging box according to claim 1, wherein: the conveying device (3) comprises a driving motor (30), a driving roller (31), a driven roller (32) and a conveying belt (33), wherein the driving motor, the driving roller, the driven roller and the conveying belt are fixed on the rack (1); the driving roller (31) and the driven roller (32) are rotationally connected with the frame (1); the conveying belt (33) is sleeved on the driving roller (31) and the driven roller (32); and an output shaft of the driving motor (30) is fixedly connected with the driving roller (31).

8. The plastic packaging device for the nourishing product packaging box according to claim 2, wherein: the mounting seat (75) comprises a mounting block (750), a rotating shaft (751) and a mounting bolt (752); the mounting block (750) is provided with a mounting chute (7500) along the direction perpendicular to the transmission direction of the conveying device (3), and a mounting bolt (752) penetrates through the mounting chute (7500) to be in threaded connection with the rack (1) so as to lock the mounting block (750) on the rack (1); one end of the rotating shaft (751) is rotatably connected with the mounting block (750), and the other end of the rotating shaft (751) is fixedly connected with the mounting frame (73).

9. The plastic packaging device for the nourishing product packaging box according to claim 1, wherein: a collecting device (8) for collecting residual plastic films (5) is arranged on the rack (1); the collecting device (8) comprises a collecting motor (80), a take-up pulley (81) and a belt guide roller (82); the collecting motor (80) is fixed on the rack (1), and the tape guide roller (82) is rotationally arranged on the rack (1); the take-up pulley (81) is fixed on an output shaft of the collecting motor (80), and the residual plastic film (5) is wound on the take-up pulley (81) by bypassing the belt guide roller (82).

10. The plastic packaging device for the nourishing product packaging box according to claim 2, wherein: the driving device (74) comprises a sealing and cutting motor (740), a swing rod (741) and a connecting rod (742); the sealing and cutting motor (740) is fixed on the frame (1); one end of the swing rod (741) is fixedly connected with the side wall of an output shaft of the seal-cutting motor (740), and the other end of the swing rod (741) is hinged with the lower end of the connecting rod (742); the upper end of the connecting rod (742) is hinged with the mounting frame (73), and the movable knife strip (72) and the fixed knife strip (70) are driven to be closed or opened in a reciprocating mode through the sealing and cutting motor (740).