Automatic plastic bag sealing and cutting device and working method thereof

Abstract

The invention relates to the technical field of automatic packaging, and discloses an automatic plastic bag sealing and cutting device and a working method thereof.The automatic plastic bag sealing and cutting device comprises an upper sealing plate, a lower sealing plate, a sealing and cutting mechanism, a material pressing mechanism, a horizontal plate, a fixing plate, a motor, a supporting plate and a supporting rod; the part, sunken in the force bearing strip, of the packaging bag upwards generates pulling force, the smooth rod is stressed to drive the rotating plate to rotate on the rotating rod, the packaging bag elastically inclines and moves under the elasticity of the spring, an elastic stretching space is provided for the packaging bag, and the situation that the excessively fixed packaging bag is pulled when the sealing lower plate conducts sealing and cutting is prevented; the packaging bag is prevented from being separated from the elastic mechanism.

Description

Technical Field

[0001] The invention relates to the technical field of automatic packaging, in particular to an automatic plastic bag sealing and cutting device and a working method thereof. Background Art

[0002] After the plastic bag is folded, it needs to be put into the packaging bag, and the two ends of the packaging bag are in an open state, so the packaging bag needs to be sealed and cut. After the packaging bag is rolled up and pulled out to the predetermined position, the sealing and cutting device is used to seal and cut one side of the opening of the packaging bag. During the sealing and cutting, the packaging bag needs to be fixed to prevent the roll material from returning after sealing and cutting, so as to facilitate the next pulling out of the roll material for sealing and cutting to form a packaging bag. At that time, a groove will be formed during the sealing and cutting, so that the pressing will drive the packaging bag again, which can easily cause the problem of pulling between the fixed packaging bag and the sealing and cutting force, affecting the sealing and fixing effect of the packaging bag. Summary of the invention

[0003] The present invention provides a plastic bag automatic sealing and cutting device and a working method thereof, which overcomes the shortcomings described in the background technology.

[0004] The technical solution adopted by the present invention to solve its technical problem is: A plastic bag automatic sealing and cutting device, comprising an upper sealing plate, a lower sealing plate, a sealing and cutting mechanism, a material pressing mechanism, a horizontal plate, a fixed plate, a motor, a support plate and a support rod, wherein the lower sealing plate is arranged on the side of the support plate through the support rod, the support plate is mounted on the surface of the fixed plate, the sealing and cutting mechanism is arranged on the upper end of the support plate, and a hydraulic device is arranged at the connection between the sealing and cutting mechanism and the support plate, and an electric signal drives the hydraulic device to drive the sealing and cutting mechanism to extend and retract up and down, the upper sealing plate is arranged on the side of the sealing and cutting mechanism above the lower sealing plate, the material pressing mechanism is arranged on the right side of the sealing and cutting mechanism, and the material pressing mechanism is perpendicular to the surface of the horizontal plate, and the motor is arranged on the surface of the sealing and cutting mechanism and driven to cut by an electric signal; The sealing and cutting mechanism is provided with a limit block, a bag cutting knife, a connecting plate, a rail, a fixed seat and a belt strip. The fixed seat is symmetrically arranged on the surface of the connecting plate. The sides of the two fixed seats are provided with rollers and belt strip limit transmission. The motor is fixed on one of the fixed seats. The output end of the motor drives the roller on the fixed seat to drive the belt strip. The limit block moves left and right on the rail on the surface of the connecting plate, and the belt strip drives the bag cutting knife on the limit block to translate and cut; The pressing mechanism is provided with an elastic plate, a force block, a force bar, a cylinder, an elastic mechanism and a telescopic rod. The cylinder is arranged inside the connecting plate, and the telescopic rod is located at the output end of the cylinder. The electric signal drives the cylinder to extend and retract the telescopic rod, and makes the force block at the lower end of the telescopic rod press the force bar. The elastic mechanism is arranged at the lower end of the force block, and the elastic mechanism is against the position of the elastic plate on the surface of the force bar. The elastic mechanism presses the packaging bag downward, and the left side of the packaging bag is elastically moved through the elastic mechanism.

[0005] A better technical solution: the elastic mechanism is provided with a smooth rod, a movable plate, a rotating plate, a limit rod, a rotating rod, a spring and a roller shaft. The smooth rod is arranged on the left side of the rotating plate. The rotating plate and the movable plate are arranged in the rotating rod at an obtuse angle hinge. The roller shaft is arranged at both ends of the rotating rod. The limit rod is arranged at the upper end of the movable plate, and the limit rod rotates at the lower end of the force block. The two ends of the spring are respectively connected to the side surfaces of the movable plate and the rotating plate. The lower end of the roller shaft presses the packaging bag against the surface of the elastic plate. When the packaging bag is sealed and cut, the left side of the packaging bag pulls the smooth rod, and the rotating plate rotates elastically on the rotating rod through the spring.

[0006] A better technical solution: when the limit rod is in a stationary state, the movable plate at the lower end of the limit rod is tilted 15° to the left, and when the movable plate at the lower end of the limit rod is pressed downward, the movable plate rotates 15° to the left with the limit rod as the center. When the spring is stationary, the rotating plate is in a horizontal state. When the force block is pressed downward, the rotating rod is inclined to the upper left corner of the surface of the force-bearing bar.

[0007] A better technical solution: the limit rod is divided into an inner tube and an outer tube, the inner tube is fixed inside the force-bearing block, and the outer tube is connected to the upper end of the movable plate, and the rotation angle between the outer tube and the inner tube is 15°.

[0008] A better technical solution: the load-bearing bar is arranged on the surface of the horizontal plate, the packaging bag passes horizontally through the surface of the load-bearing bar, and the load-bearing bar is arranged at a corresponding position below the load-bearing block.

[0009] A better technical solution: the elastic plate is made of rubber. When the roller drives the packaging bag to press against the surface of the elastic plate, it has the effect of increasing friction. The roller rolls on the surface of the elastic plate through the downward pressing force of the movable plate, which has the effect of increasing the fixing force of the roller on the packaging bag.

[0010] A better technical solution: the sealing upper plate is provided with a hollow groove, a hot melt strip, a splicing plate and a heat fuser. The electrical signal drives the heat fuser inside the splicing plate and heats the "U"-shaped hot melt strip at the lower end of the heat fuser, so that the hot melt strip presses the packaging bag on the surface of the sealing lower plate when the splicing plate descends. The hollow groove is arranged inside the splicing plate, and the splicing plate is fixed to the side of the connecting plate. The bag cutting knife moves left and right in the hollow groove and cuts the packaging bag below.

[0011] A better technical solution: the lower sealing plate is provided with a groove corresponding to the hot melt strip, and a concave groove is provided on the surface of the lower sealing plate directly below the hollow groove. When the hot melt strip melts the packaging bag at the groove position of the lower sealing plate downward, the bag cutting knife moves in the hollow groove and cuts the packaging bag at the concave groove position on the surface of the lower sealing plate.

[0012] A preferred technical solution: the upper surface of the sealing lower plate and the bearing strip are located on the same horizontal line, and when the hot melt strip is pressed downward, the packaging bag is pulled to move on the surface of the sealing lower plate and the bearing strip.

[0013] Based on the working method of the automatic sealing and cutting device for plastic bags described above, the working method includes the following specific steps: S1: The packaging bag passes through the surface of the horizontal plate and the hollow position below the sealing and cutting mechanism. The packaging bag passes through the surface of the lower sealing plate. After the packaging bag is stretched and stationary, the electric signal of the cylinder in the pressing mechanism drives the telescopic rod to compress downward, so that the elastic mechanism at the lower end of the force block presses the packaging bag passing through the surface of the bearing bar; S2: After the packaging bag is fixed by the pressing mechanism, the electric signal drives the hydraulic device to lift the sealing and cutting mechanism, so that the upper sealing plate seals and cuts the packaging bag passing through the lower sealing plate position; S3: After the sealing and cutting is completed, the electric signal drives the motor, so that the output end of the motor drives the roller on the fixed seat to transmit the belt, and then the belt drives the limit block to slide linearly on the rail, so that the bag cutting knife moves left and right to cut the packaging bag under the sealing upper plate. After the cutting is completed, the electric signal drives the hydraulic press and the motor to reset; S4: When the upper sealing plate seals and cuts the packaging bag, the packaging bag is driven to move downward and is pulled at the left protrusion of the elastic plate. Then the packaging bag presses the rotating plate upward outside the smooth rod, causing the rotating plate to rotate under the elastic force of the spring. The straight-line distance from the elastic plate to the rotating rod causes the rotating plate to bend relative to the packaging bag through the elasticity of the spring.

[0014] Compared with the prior art, this technical solution has the following advantages: In the present invention, when the upper sealing plate is sealed downward, the packaging bag is pulled to the left. At this time, the part of the packaging bag that is sunk in the position of the load-bearing bar generates a pulling force upward, so that the smooth rod is forced to drive the rotating plate to rotate on the rotating rod, and the packaging bag performs elastic tilting movement under the elastic force of the spring, thereby providing an elastic stretching space for the packaging bag, preventing the packaging bag that is too fixed from being pulled when the lower sealing plate is sealed and cut, and avoiding the packaging bag from being pulled out of the elastic mechanism.

[0015] In the present invention, an electrical signal drives the hot melter to heat the hot melt strip, so that the hot melt strip heats the packaging bag to a gel-like state to form a sealing effect. After the heating is completed, the bag cutting knife moves left and right in the hollow groove in the splicing plate, and cuts the packaging bag at the concave groove position on the surface of the sealing lower plate, thereby achieving an automatic sealing cutting effect on the packaging bag. The "U"-shaped hot melt strip is limited by the groove on the surface of the sealing lower plate to avoid the heating position being disconnected by the tension force of the packaging bag due to the weak fixing force when the packaging bag is heated. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0017] Figure 1 This is an overall diagram of the present invention.

[0018] Figure 2It is a three-dimensional schematic diagram of the sealing and cutting mechanism.

[0019] Figure 3 It is a side view of the pressing mechanism.

[0020] Figure 4 It is a three-dimensional schematic diagram of the elastic mechanism.

[0021] Figure 5 A side view of the sealing upper plate.

[0022] Figure 6 It is a three-dimensional schematic diagram of the limit rod.

[0023] In the figure: sealing upper plate-1, sealing lower plate-2, sealing and cutting mechanism-3, pressing mechanism-4, horizontal plate-5, fixed plate-6, motor-7, support plate-8, support rod-9.

[0024] Limit block-31, bag cutting knife-32, connecting plate-33, rail-34, fixing seat-35, belt strip-36.

[0025] Elastic plate-41, force block-42, load-bearing bar-43, cylinder-44, elastic mechanism-45, telescopic rod-46.

[0026] Smooth rod 451, movable plate 452, rotating plate 453, limiting rod 454, rotating rod 455, spring 456, roller 457.

[0027] Hollow groove-11, hot melt strip-12, splicing plate-13, hot melter-14. DETAILED DESCRIPTION

[0028] like Figures 1 to 6 As shown, the present invention proposes an automatic sealing and cutting device for plastic bags, comprising an upper sealing plate 1, a lower sealing plate 2, a sealing and cutting mechanism 3, a pressing mechanism 4, a horizontal plate 5, a fixed plate 6, a motor 7, a support plate 8 and a support rod 9, wherein the lower sealing plate 2 is arranged on the side of the support plate 8 through the support rod 9, and the support plate 8 is installed on the surface of the fixed plate 6, the sealing and cutting mechanism 3 is arranged on the upper end of the support plate 8, and a hydraulic device is arranged at the connection between the sealing and cutting mechanism 3 and the support plate 8, and the hydraulic device is driven by an electric signal to drive the sealing and cutting mechanism 3 to extend and retract up and down, the upper sealing plate 1 is arranged on the side of the sealing and cutting mechanism 3 above the lower sealing plate 2, and the pressing mechanism 4 is arranged on the right side of the sealing and cutting mechanism 3, and the pressing mechanism 4 is perpendicular to the surface of the horizontal plate 5, and the motor 7 is arranged on the surface of the sealing and cutting mechanism 3 and driven by an electric signal to cut; The sealing and cutting mechanism 3 is provided with a limit block 31, a bag cutting knife 32, a connecting plate 33, a rail 34, a fixed seat 35 and a belt strip 36. The fixed seat 35 is symmetrically arranged on the surface of the connecting plate 33. The sides of the two fixed seats 35 are provided with rollers and the belt strip 36 for limiting transmission. The motor 7 is fixed on one of the fixed seats 35. The output end of the motor 7 drives the roller on the fixed seat 35 to drive the belt strip 36. The limit block 31 moves left and right on the rail 34 on the surface of the connecting plate 33, and the belt strip 36 drives the bag cutting knife 32 on the limit block 31 to translate and cut; The pressing mechanism 4 is provided with an elastic plate 41, a force block 42, a force bar 43, a cylinder 44, an elastic mechanism 45 and a telescopic rod 46. The cylinder 44 is arranged inside the connecting plate 33, and the telescopic rod 46 is located at the output end of the cylinder 44. The electric signal drives the cylinder 44 to extend and retract the telescopic rod 46, and makes the force block 42 at the lower end of the telescopic rod 46 press the force bar 43. The elastic mechanism 45 is arranged at the lower end of the force block 42, and the elastic mechanism 45 is against the position of the elastic plate 41 on the surface of the force bar 43. The elastic mechanism 45 presses the packaging bag downward, and the left side of the packaging bag is elastically moved through the elastic mechanism 45.

[0029] In the present invention, the packaging bag is horizontally pulled from the bearing strip 43 on the surface of the horizontal plate 5. After the pulling is completed, the electrical signal drives the cylinder 44 to press and fix the packaging bag on the surface of the bearing strip 43. When the material is pressed and fixed, the elastic mechanism 45 presses the packaging bag, so that the packaging bag is sunk into the surface of the elastic plate 41 in the middle of the bearing strip 43, and the elastic mechanism 45 rolls again on the surface of the elastic plate 41 to strengthen the pressing force. After the pressing is completed, the hydraulic machine drives the sealing and cutting mechanism 3 to move up and down, so that the sealing upper plate 1 moves downward to the corresponding sealing lower plate 2 position to seal the packaging bag. After the sealing is completed, the electrical signal drives the motor 7 to drive the belt strip 36 on the surface of the sealing and cutting mechanism 3, and then drives the limit block 31 to make linear left and right movements along the sealing upper plate 1 on the track 34. At this time, the bag cutting knife 32 on the side of the limit block 31 follows the movement and cuts the packaging bag under the sealing upper plate 1 to form a sealing and cutting effect.

[0030] Among them, the elastic mechanism 45 is provided with a smooth rod 451, a movable plate 452, a rotating plate 453, a limiting rod 454, a rotating rod 455, a spring 456 and a roller 457. The smooth rod 451 is arranged on the left side of the rotating plate 453, and the rotating plate 453 and the movable plate 452 are arranged in the rotating rod 455 at an obtuse angle hinge. The roller 457 is arranged at both ends of the rotating rod 455. The limiting rod 454 is arranged at the upper end of the movable plate 452, and the limiting rod 454 rotates at the lower end of the force block 42. The two ends of the spring 456 are respectively connected to the sides of the movable plate 452 and the rotating plate 453. The lower end of the roller 457 presses the packaging bag against the surface of the elastic plate 41. When the packaging bag is sealed and cut, the left side of the packaging bag pulls the smooth rod 451, and the rotating plate 453 elastically rotates on the rotating rod 455 through the spring 456.

[0031] Furthermore, when the limiting rod 454 is in a stationary state, the movable plate 452 at the lower end of the limiting rod 454 is tilted 15° to the left, and when the movable plate 452 at the lower end of the limiting rod 454 is pressed downward, the movable plate 452 rotates 15° to the left with the limiting rod 454 as the center. When the spring 456 is stationary, the rotating plate 453 is in a horizontal state. When the force block 42 is pressed downward, the rotating rod 455 is inclined to the upper left corner of the surface of the force-bearing bar 43.

[0032] In addition, the limiting rod 454 is divided into an inner tube and an outer tube. The inner tube is fixed inside the force-bearing block 42, and the outer tube is connected to the upper end of the movable plate 452. The rotation angle between the outer tube and the inner tube is 15°.

[0033] Furthermore, the load-bearing bar 43 is arranged on the surface of the horizontal plate 5 , and the packaging bag passes horizontally through the surface of the load-bearing bar 43 , and the load-bearing bar 43 is arranged at a corresponding position below the load-bearing block 42 .

[0034] In addition, the elastic plate 41 is made of rubber. When the roller 457 drives the packaging bag to press against the surface of the elastic plate 41, it has the effect of increasing friction. The roller 457 rolls on the surface of the elastic plate 41 through the downward pressing force of the movable plate 452, which has the effect of increasing the fixing force of the roller 457 on the packaging bag.

[0035] In the present invention, when the cylinder 44 drives the telescopic rod 46 to press downward, the force block 42 drives the elastic mechanism 45 to squeeze the packaging bag on the surface of the bearing bar 43, and the packaging bag sinks into the middle of the bearing bar 43 to form a concave shape. Under the downward pressing force, the roller 457 and the smooth rod 451 pull the packaging bag to rotate the inclined movable plate 452 by 15°, so that the roller 457 rolls on the surface of the elastic plate 41 and increases the squeezing force on the packaging bag, and when the sealing upper plate 1 is sealed downward, the packaging bag is pulled to the left. At this time, the part of the packaging bag that is sunk in the position of the bearing bar 43 generates a pulling force upward, so that the smooth rod 451 is forced to drive the rotating plate 453 to rotate on the rotating rod 455, and the packaging bag performs elastic tilting activity under the elastic force of the spring 456, providing a space for elastic stretching for the packaging bag, preventing the sealing lower plate 2 from pulling the overly fixed packaging bag when sealing and cutting, and avoiding pulling the packaging bag out of the elastic mechanism 45.

[0036] Among them, the sealing upper plate 1 is provided with a hollow groove 11, a hot melt strip 12, a splicing plate 13 and a heat melter 14. The electrical signal drives the heat melter 14 inside the splicing plate 13, and heats the "U"-shaped hot melt strip 12 at the lower end of the heat melter 14, so that the hot melt strip 12 presses the packaging bag on the surface of the sealing lower plate 2 when the splicing plate 13 descends. The hollow groove 11 is arranged inside the splicing plate 13, and the splicing plate 13 is fixed to the side of the connecting plate 33. The bag cutting knife 32 moves left and right in the hollow groove 11 and cuts the packaging bag below.

[0037] In addition, the sealing lower plate 2 is provided with a groove corresponding to the hot melt strip 12, and a concave groove is provided on the surface of the sealing lower plate 2 directly below the hollow groove 11. When the hot melt strip 12 melts the packaging bag at the groove position of the sealing lower plate 2 downward, the bag cutting knife 32 moves in the hollow groove 11 and cuts the packaging bag at the concave groove position on the surface of the sealing lower plate 2.

[0038] Furthermore, the upper surfaces of the sealing lower plate 2 and the bearing bar 43 are located on the same horizontal line, and when the hot melt bar 12 is pressed downward, the packaging bag is pulled to move on the surfaces of the sealing lower plate 2 and the bearing bar 43 .

[0039] In the present invention, after the sealing upper plate 1 presses downward the packaging bag on the surface of the sealing lower plate 2, the hot melt strip 12 drives the packaging bag to fall into the groove on the surface of the sealing lower plate 2 for limiting, and at the same time, the electric signal drives the hot melt 14 to heat the hot melt strip 12, so that the hot melt strip 12 heats the packaging bag to a gelatinous state to form a sealing effect, and after the heating is completed, the bag cutting knife 32 moves left and right in the hollow groove 11 in the splicing plate 13, and cuts the packaging bag at the concave groove position on the surface of the sealing lower plate 2, thereby achieving an automatic sealing cutting effect on the packaging bag, and the "U"-shaped hot melt strip 12 is limited by the groove on the surface of the sealing lower plate 2, so as to avoid the heating position being disconnected by the tension force of the packaging bag due to the weak fixing force when the packaging bag is heated.

[0040] Based on the working method of the automatic sealing and cutting device for plastic bags described above, the working method includes the following specific steps: S1: The packaging bag passes through the surface of the horizontal plate 5 and the hollow position below the sealing and cutting mechanism 3, and passes through the surface of the sealing lower plate 2. After the packaging bag is stretched and stationary, the cylinder 44 in the pressing mechanism 4 drives the telescopic rod 46 to compress downward with an electrical signal, so that the elastic mechanism 45 at the lower end of the force block 42 presses the packaging bag passing through the surface of the force bar 43; S2: After the packaging bag is fixed by the pressing mechanism 4, the electric signal drives the hydraulic machine to lift the sealing and cutting mechanism 3, so that the packaging bag passing through the sealing upper plate 1 to the sealing lower plate 2 below is sealed and cut; S3: After the sealing and cutting is completed, the electric signal drives the motor 7, so that the output end of the motor 7 drives the roller on the fixed seat 35 to transmit the belt strip 36, and then the belt strip 36 drives the limit block 31 to slide linearly on the rail 34, so that the bag cutting knife 32 moves left and right to cut the packaging bag under the sealing upper plate 1. After the cutting is completed, the electric signal drives the hydraulic press and the motor 7 to reset; S4: When the upper sealing plate 1 seals and cuts the packaging bag, it drives the packaging bag to move downward and pulls the packaging bag at the left protrusion of the elastic plate 41. Then the packaging bag presses the rotating plate 453 upward outside the smooth rod 451, so that the rotating plate 453 rotates under the elastic force of the spring 456. The straight-line distance from the elastic plate 41 to the rotating rod 455 causes the rotating plate 453 to bend relative to the packaging bag through the elasticity of the spring 456.

[0041] The above description is only a preferred embodiment of the present invention, and therefore cannot be used to limit the scope of the present invention. That is, equivalent changes and modifications made according to the patent scope of the present invention and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A plastic bag automatic sealing and cutting device, characterized in that: The invention comprises an upper sealing plate (1), a lower sealing plate (2), a sealing and cutting mechanism (3), a material pressing mechanism (4), a horizontal plate (5), a fixed plate (6), a motor (7), a support plate (8) and a support rod (9), wherein the lower sealing plate (2) is arranged on the side of the support plate (8) through the support rod (9), the support plate (8) is mounted on the surface of the fixed plate (6), the sealing and cutting mechanism (3) is arranged on the upper end of the support plate (8), and a hydraulic device is arranged at the connection between the sealing and cutting mechanism (3) and the support plate (8), and an electric signal drives the hydraulic device to drive the sealing and cutting mechanism (3) to extend and retract upward and downward, the upper sealing plate (1) is arranged on the side of the sealing and cutting mechanism (3) above the lower sealing plate (2), the material pressing mechanism (4) is arranged on the right side of the sealing and cutting mechanism (3), and the material pressing mechanism (4) is perpendicular to the surface of the horizontal plate (5), and the motor (7) is arranged on the surface of the sealing and cutting mechanism (3) to drive cutting by electric signals; The material pressing mechanism (4) is provided with an elastic plate (41), a force block (42), a force bar (43), a cylinder (44), an elastic mechanism (45) and a telescopic rod (46); the cylinder (44) is arranged inside the connecting plate (33), and the telescopic rod (46) is located at the output end of the cylinder (44); an electrical signal drives the cylinder (44) to extend and retract the telescopic rod (46), and causes the force block (42) at the lower end of the telescopic rod (46) to press the force bar (43); the elastic mechanism (45) is arranged at the lower end of the force block (42), and the elastic mechanism (45) abuts against the position of the elastic plate (41) on the surface of the force bar (43); the elastic mechanism (45) presses the packaging bag downward, and the left side of the packaging bag is elastically moved by the elastic mechanism (45); The elastic mechanism (45) is provided with a smooth rod (451), a movable plate (452), a rotating plate (453), a limit rod (454), a rotating rod (455), a spring (456) and a roller shaft (457); the smooth rod (451) is arranged on the left side of the rotating plate (453); the rotating plate (453) and the movable plate (452) are hinged at an obtuse angle and arranged in the rotating rod (455); the roller shaft (457) is arranged at both ends of the rotating rod (455); The rod (454) is arranged at the upper end of the movable plate (452), and the limiting rod (454) rotates at the lower end of the force block (42). The two ends of the spring (456) are respectively connected to the side surfaces of the movable plate (452) and the rotating plate (453). The lower end of the roller (457) presses the packaging bag against the surface of the elastic plate (41). When the packaging bag is sealed and cut, the left side of the packaging bag pulls the smooth rod (451), and the rotating plate (453) elastically rotates on the rotating rod (455) through the spring (456).

2. The automatic sealing and cutting device for plastic bags according to claim 1, characterized in that: The sealing and cutting mechanism (3) is provided with a limit block (31), a bag cutting knife (32), a connecting plate (33), a rail (34), a fixed seat (35) and a belt strip (36); the fixed seat (35) is symmetrically arranged on the surface of the connecting plate (33); rollers and the belt strip (36) are provided on the sides of the two fixed seats (35) for limiting transmission; the motor (7) is fixed on one of the fixed seats (35); the output end of the motor (7) drives the roller on the fixed seat (35) to drive the belt strip (36); the limit block (31) moves left and right on the track of the rail (34) on the surface of the connecting plate (33), and enables the belt strip (36) to drive the bag cutting knife (32) on the limit block (31) to translate and cut.

3. The automatic sealing and cutting device for plastic bags according to claim 1, characterized in that: When the limiting rod (454) is in a stationary state, the movable plate (452) at the lower end of the limiting rod (454) is tilted 15° to the left, and when the movable plate (452) at the lower end of the limiting rod (454) is pressed downward, the movable plate (452) rotates 15° to the left with the limiting rod (454) as the center, and when the spring (456) is stationary, the rotating plate (453) is in a horizontal state, and when the force block (42) is pressed downward, the rotating rod (455) is inclined to the upper left corner of the surface of the force bearing bar (43).

4. The automatic sealing and cutting device for plastic bags according to claim 1, characterized in that: The sealing upper plate (1) is provided with a hollow groove (11), a hot melt strip (12), a splicing plate (13) and a hot melter (14); an electrical signal drives the hot melter (14) inside the splicing plate (13) and heats the "U"-shaped hot melt strip (12) at the lower end of the hot melter (14), so that the hot melt strip (12) presses the packaging bag on the surface of the sealing lower plate (2) when the splicing plate (13) descends; the hollow groove (11) is arranged inside the splicing plate (13), and the splicing plate (13) is fixed to the side of the connecting plate (33); the bag cutting knife (32) moves left and right in the hollow groove (11) and cuts the packaging bag below.

5. The automatic sealing and cutting device for plastic bags according to claim 4, characterized in that: The sealing lower plate (2) is provided with a groove corresponding to the hot melt strip (12), and a concave groove is provided on the surface of the sealing lower plate (2) directly below the hollow groove (11). When the hot melt strip (12) heat-melts the packaging bag at the position of the groove of the sealing lower plate (2), the bag cutting knife (32) moves in the hollow groove (11) and cuts the packaging bag at the position of the concave groove on the surface of the sealing lower plate (2).

6. The automatic sealing and cutting device for plastic bags according to claim 5, characterized in that: The upper surfaces of the sealing lower plate (2) and the bearing strip (43) are located on the same horizontal line, and when the hot melt strip (12) is pressed downward, the packaging bag is pulled to move on the surfaces of the sealing lower plate (2) and the bearing strip (43).

7. A working method of an automatic plastic bag sealing and cutting device according to claim 2, characterized in that: The working method comprises the following specific steps: S1: The packaging bag passes through the surface of the horizontal plate (5) and passes through the hollow position below the sealing and cutting mechanism (3). The packaging bag passes through the surface of the sealing lower plate (2). After the packaging bag is stretched and stationary, the cylinder (44) in the pressing mechanism (4) drives the telescopic rod (46) to compress downward via an electrical signal, so that the elastic mechanism (45) at the lower end of the force block (42) presses the packaging bag passing through the surface of the force bar (43); S2: After the packaging bag is fixed by the pressing mechanism (4), the electric signal drives the hydraulic device to raise and lower the sealing and cutting mechanism (3), so that the upper sealing plate (1) seals and cuts the packaging bag passing through the position of the lower sealing plate (2) below; S3: After the sealing and cutting is completed, the electric signal drives the motor (7), so that the output end of the motor (7) drives the roller on the fixed seat (35) to transmit the belt (36), and then the belt (36) drives the limit block (31) to slide linearly on the rail (34), so that the bag cutting knife (32) moves left and right to cut the packaging bag below the sealing upper plate (1). After the cutting is completed, the electric signal drives the hydraulic press and the motor (7) to reset; S4: When the upper sealing plate (1) seals and cuts the packaging bag, the packaging bag is driven to move downward and is pulled at the left protrusion of the elastic plate (41). Then, the packaging bag presses the rotating plate (453) upward outside the smooth rod (451), causing the rotating plate (453) to rotate under the elastic force of the spring (456). The straight-line distance from the elastic plate (41) to the rotating rod (455) causes the rotating plate (453) to bend relative to the packaging bag through the elasticity of the spring (456).

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