Loop seal cutting device and method

Abstract

The application provides a sealing and cutting device and method, which comprises a sealing and cutting mechanism, a sealing and cutting area product conveying line, a sealing and cutting pad strip and a sealing and cutting mechanism circulating movement mechanism. The sealing and cutting pad strip is conveyed to a sealing and cutting starting position corresponding to a sealing and cutting starting time and is conveyed forward along with the forward conveying of the film-coated product, and is returned after the sealing and cutting work is completed. The sealing and cutting mechanism is conveyed to the sealing and cutting starting position corresponding to the sealing and cutting starting time and is conveyed forward along with the forward conveying of the product, and the sealing and cutting is completed in the forward conveying process. The operation track of the sealing and cutting work head comprises a forward conveying section corresponding to the sealing and cutting work, a descending section before the sealing and cutting starting position and an ascending section after the forward conveying section, and a returning section between the ascending section and the descending section. The application can perform the sealing and cutting work in the product conveying process, the product does not need to stop, and two or more sets of sealing and cutting mechanisms can be circulated and alternately worked, the sealing and cutting work can be continuously performed, and the sealing and cutting efficiency is greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of packaging machinery, and relates to a sealing and cutting device and a sealing and cutting method applied to a film wrapping machine. BACKGROUND

[0002] The film wrapping machine is a device for wrapping products with plastic film, such as wrapping groups of beverage bottles or cans. In the existing film wrapping machine, a sealing and cutting station is fixed in the film wrapping machine, and a lifting sealing and cutting mechanism is arranged at the sealing and cutting station. When a product group is pushed against the film and passes through the sealing and cutting station until the rear part of the product group reaches the sealing and cutting station, the sealing and cutting mechanism is lowered to seal and cut the film for a period of time. The rear end of the front film wrapping is sealed and cut, the upper film and the lower film are connected, and the sealing line and the connecting line are cut. Since the wrapping film has a certain thickness, a certain period of time is required for sealing and cutting. Therefore, the sealing and cutting device of this structure has a long stop time during sealing and cutting, and the working efficiency needs to be improved. SUMMARY

[0003] The purpose of the present application is to provide a circulating sealing and cutting device with higher sealing and cutting efficiency. To this end, the present application adopts the following technical solutions:

[0004] The circulating sealing and cutting device comprises a sealing and cutting mechanism, and the sealing and cutting mechanism is provided with a sealing and cutting working head. The circulating sealing and cutting device further comprises a sealing and cutting area product conveying line, a sealing and cutting pad strip, and a sealing and cutting mechanism circulating movement mechanism. The sealing and cutting pad strip is connected with the circulating conveying mechanism and is circulated and conveyed. The sealing and cutting pad strip can be conveyed to the sealing and cutting starting position in correspondence with the sealing and cutting starting time and is conveyed forward along with the forward conveying of the film-wrapped product. After the sealing and cutting work is completed, the sealing and cutting pad strip returns. The sealing and cutting mechanism is connected with the sealing and cutting mechanism circulating movement mechanism and can be conveyed to the sealing and cutting starting position in correspondence with the sealing and cutting starting time and is conveyed forward along with the forward conveying of the product. The sealing and cutting mechanism completes the sealing and cutting during the forward conveying process. The running track of the sealing and cutting working head comprises a forward conveying section corresponding to the sealing and cutting work, a descending section before the sealing and cutting starting position, an ascending section after the forward conveying section, and a returning section between the ascending section and the descending section.

[0005] On the basis of the above-mentioned technical solutions, the present application can further adopt the following further technical solutions, or use these further technical solutions in combination:

[0006] The circulating sealing and cutting device is provided with at least two sets of sealing and cutting mechanisms which perform sealing and cutting work in sequence. The sealing and cutting mechanisms are arranged on the sealing and cutting mechanism circulating movement mechanism to realize the circulating sealing and cutting action.

[0007] The circulating sealing and cutting device is provided with two sets of sealing and cutting mechanisms which perform sealing and cutting work in alternation. The two sets of sealing and cutting mechanisms have their respective sealing and cutting mechanism circulating movement mechanisms.

[0008] The two sets of sealing and cutting mechanisms each have a sealing and cutting mechanism circulating movement mechanism located on the two sides of the conveying route of the product being wrapped by the film, and the sealing and cutting work head is long-armed, with its first end connected to the sealing and cutting mechanism on the side where the circulating movement mechanism is located, and its second end extending to the other side to match the width of the film, and the two sets of sealing and cutting mechanisms are staggered and do not interfere with each other.

[0009] The circulating conveying mechanism of the sealing and cutting pad strip uses a sealing and cutting area product conveying line, and the sealing and cutting pad strip is located between or on the product support structure on the sealing and cutting area product conveying line.

[0010] The circulating conveying mechanism of the sealing and cutting pad strip uses a sealing and cutting pad strip circulating conveying mechanism other than the sealing and cutting area product conveying line, and the pad strip circulating conveying mechanism contains a conveying stroke that coincides with the sealing and cutting area product conveying line, and the coinciding stroke corresponds to the sealing and cutting starting position to the sealing and cutting end position, and in the coinciding stroke, the sealing and cutting pad strip is located between or above the product support structure on the sealing and cutting area product conveying line.

[0011] The forward conveying section ends before the conveying end of the sealing and cutting area product conveying line.

[0012] A first product conveying line independent of the sealing and cutting area product conveying line is provided before the sealing and cutting area product conveying line, and the first product conveying line is provided with a product blocking mechanism; the sealing and cutting starting position is located on the conveying path inside the sealing and cutting area product conveying line; the circulating sealing and cutting device is further provided with a driving mechanism, and the driving mechanism includes a driving rod and a driving rod circulating mechanism, and the circulating sealing and cutting device is provided with a conveying connection mechanism between the first product conveying line and the sealing and cutting area product conveying line, and the driving rod circulating mechanism has a driving path that starts from behind the first product conveying line to the sealing and cutting starting position.

[0013] The descending section is a trajectory that gradually runs forward and downward from behind the sealing and cutting starting position, including at least a running trajectory that runs obliquely forward and downward from behind the sealing and cutting starting position to the sealing and cutting starting position in the latter half of the descending section, or a running trajectory that first runs forward to above the sealing and cutting starting position from behind the sealing and cutting starting position and then descends to the sealing and cutting starting position.

[0014] Another object of the present application is to provide a film wrapping machine circulating sealing and cutting method with higher sealing and cutting efficiency, and for this purpose, the present application adopts the following technical solutions:

[0015] The film wrapping machine circulating sealing and cutting method has the following characteristics:

[0016] At least two sets of sealing and cutting mechanisms are used to perform sealing and cutting work in sequence;

[0017] The sealing work is performed in a stroke range, the sealing work on the film uses a sealing work head to follow the product and performs the sealing work during the following process, the running track of the sealing work head includes a forward conveying section corresponding to the sealing work, a descending section before the sealing work starting position and an ascending section after the forward conveying section, and a returning section between the ascending section and the descending section, and the circulating sealing method includes the following processes:

[0018] S1, the first sealing mechanism completes the sealing work, the connected film is straightened by the upper film tensioning mechanism and the lower film tensioning mechanism, is located in front of the sealing work starting position, and waits for the next product group to enter

[0019] S2, the front end of the product group is conveyed against the packaging film, the first sealing mechanism rises to give way, and the second sealing mechanism runs to the rear of the sealing work starting position;

[0020] S3, connected to S2, the rear end of the product group is conveyed to the sealing work starting position, the second sealing mechanism moves from the rear of the conveyed product group to the front and descends to the sealing work starting position to perform the sealing work;

[0021] S4, the product group is continuously conveyed forward without stopping, and at the same time, the second sealing mechanism performs the sealing work in the following process.

[0022] According to the technical scheme of the present application, the two or more sets of sealing mechanisms are used to perform the circulating motion containing the product conveying route and the lifting route, and in the product conveying track, the circulating conveying of the sealing pad is combined, the sealing work can be performed in the product conveying process, the product does not need to stop, and the two or more sets of sealing mechanisms can be used to perform the circulating and alternating work, the sealing work can be continuously performed, and the sealing efficiency is greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of an embodiment of the present application.

[0024] Figure 2 It is Figure 1 In the embodiment shown, the running track of the upper film and the lower film and the combination of the product conveying line and the sealing pad circulating structure in the sealing area are shown.

[0025] Figure 3 It is Figure 1 In the embodiment shown, the schematic diagram of the two circulating motion sealing mechanisms is shown.

[0026] Figure 4 It is a working schematic diagram of an embodiment of the present application.

[0027] Figure 5 It is Figure 4 The schematic diagram of the circulating track of the sealing mechanism is shown.

[0028] Figure 6 In accordance with Figure 5 The working process demonstration diagram of the sealing and cutting mechanism cycle trajectory is shown.

[0029] Among them, S1 is the initial state, at this time, the first sealing and cutting mechanism completes the sealing and cutting work, the upper film and the lower film are hot-sealed and sealed at the rear end of the film-wrapped product, the upper film and the lower film are hot-bonded and connected, the connection line and the sealing line are disconnected, and the connected film is straightened by the upper film tensioning mechanism and the lower film tensioning mechanism and is located in front of the hot-sealing starting position, waiting for the next product group to enter; S2 is the state when the front end of the product group is conveyed forward against the packaging film. At this time, the first sealing and cutting mechanism has risen to make way, and the second sealing and cutting mechanism has run to the rear of the sealing and cutting starting position; S3 is the continuation of S2, the rear end of the product group is conveyed to the sealing and cutting starting position, the second sealing and cutting mechanism moves forward from the rear of the product group being conveyed and descends to the sealing and cutting starting position, and starts the sealing and cutting work; S4, the product group continues to be conveyed forward without stopping, and at the same time, the second sealing and cutting mechanism performs the sealing and cutting work. DETAILED DESCRIPTION

[0030] Refer to the accompanying drawings. The cyclic sealing and cutting device provided by the present invention includes a sealing and cutting mechanism, wherein the sealing and cutting mechanism is provided with a sealing and cutting working head 1. The cyclic sealing and cutting device includes a sealing and cutting area product conveying line 301, a sealing and cutting cushion strip 2, and a sealing and cutting mechanism circulating motion mechanism 200. The sealing and cutting cushion strip 2 is connected to the circulating conveying mechanism and is cyclically conveyed. It can be conveyed to the sealing and cutting starting position C in response to the sealing and cutting start timing and conveyed forward as the product 300 (the product group requiring film wrapping) is conveyed forward. After the sealing and cutting work is completed, it is circulated back to the sealing and cutting starting position C, achieving better sealing and cutting effect and sealing and cutting efficiency. The sealing and cutting mechanism is connected to the sealing and cutting mechanism circulating motion mechanism 200 and can be transported to the sealing and cutting starting position C corresponding to the sealing and cutting starting timing and conveyed forward as the film-wrapped product 300 is conveyed forward, completing the sealing and cutting during the forward conveying process. The running trajectory of the sealing and cutting working head 1 includes a forward conveying section R1 corresponding to the sealing and cutting work, a descending section R4 before the sealing and cutting starting position C, an ascending section R2 after the forward conveying section R1, and a return section R3 between the ascending section R2 and the descending section R4.

[0031] Preferably, if Figure 5 、 6 As shown, the descending section R4 is an obliquely downward trajectory, or at least the latter half of the descending section is an obliquely forward and downward trajectory from the rear of the sealing and cutting starting position C, and runs obliquely downward from the rear to the sealing and cutting starting position C. In this way, the running trajectory of the sealing and cutting work head 1 presents an inverted trapezoidal feature, which is more efficient than other circular trajectories such as rectangles. The sealing and cutting work head 1 can reach the sealing and cutting starting position C1 from the rear without the product pausing or waiting, and the product conveying line 301 in the sealing and cutting area continuously and non-stop transports the product forward.

[0032] The cycle sealing and cutting device is provided with two sets of sealing and cutting mechanisms 101, 102 staggered to perform sealing and cutting work, which can further improve work efficiency, and the two sets of sealing and cutting mechanisms 101, 102 have their respective sealing and cutting mechanism cycle movement mechanisms, so that the speed of each can be freely adjusted, and the work connection and cooperation of the two sealing and cutting work heads 1 can be better controlled. The sealing and cutting mechanism cycle movement mechanisms 200 of the two sets of sealing and cutting mechanisms are respectively located on the two sides of the conveying route of the product with a film, and the sealing and cutting work head 1 is long-arm-shaped, with its first end connected to the sealing and cutting mechanism on the side provided with the cycle movement mechanism, and its second end extending to the other side to the width of the matching film. The two sets of sealing and cutting mechanisms stagger and do not interfere with each other. The sealing and cutting work head 1 is a hot knife capable of sealing and cutting the film, and its cross section can be inverted triangular or inverted trapezoidal with a very short bottom width.

[0033] In Figure 1 、 Figure 4 the embodiment, the cycle conveying mechanism of the sealing and cutting pad strip 2 adopts a sealing and cutting area product conveying line 301, which adopts a cycle conveying mechanism such as a chain or belt cycle conveying device, and a product support structure 302 such as a support strip or support plate is arranged on the cycle conveying mechanism, and a sealing and cutting pad strip 2 is arranged at a distance. In the cycle process, when the rear end of each product group reaches the sealing and cutting starting position C1, the sealing and cutting pad strip 2 also reaches the position and cooperates with the sealing and cutting work head 1 descending from above. The sealing and cutting pad strip 2 can be connected to the chain or belt of the cycle conveying device between the product support structures on the sealing and cutting area product conveying line or directly on the product support structures.

[0034] In Figure 5 、 Figure 6 the embodiment, the cycle conveying mechanism of the sealing and cutting pad strip 2 adopts a sealing and cutting area product conveying line 301, which adopts a cycle conveying mechanism such as a chain or belt cycle conveying device. The pad strip cycle conveying line 20 contains a conveying stroke coinciding with the sealing and cutting area product conveying line 301, and the coinciding stroke corresponds to the sealing and cutting starting position C to the end of the sealing and cutting work, and in the coinciding stroke, the sealing and cutting pad strip 2 is located between the product support structures on the sealing and cutting area product conveying line or above the product support structures of the sealing and cutting area product conveying line, and matches the running speed of the sealing and cutting area product conveying line. The length of the sealing and cutting pad strip 2 can be longer than the product support structure, so that the width of the pad strip cycle conveying line 20 is different from the width of the sealing and cutting area product conveying line 301, and they cooperate without interfering with each other.

[0035] For Figure 5 、 Figure 6In the embodiment of the application, the length of the cutting pad 2 is longer than the product supporting structure, and the circulation path of the cutting pad 2 is also raised upward 21 at the end of the forward conveying path, that is, the end of the conveying stroke coinciding with the cutting area product conveying line 301, and then is conveyed forward and downward, and then is circulated backward. The upwardly and downwardly inclined path can reasonably reduce the gap and smoothly convey the product.

[0036] In the application, the forward conveying section ends before the conveying end of the cutting area product conveying line. A first product conveying line 400 is arranged in the same straight line before the cutting area product conveying line 301, and a product blocking mechanism 401, such as a power-driven blocking rod or pressing plate, is arranged in the first product conveying line. The cutting start position C is arranged on the conveying path inside the cutting area product conveying line 301. After the cutting area product conveying line 301, a product output device 500 or a product receiving table can be arranged.

[0037] The circulation cutting device further comprises a driving mechanism including a driving rod 701 and a driving rod circulation mechanism 702. A conveying connection mechanism, such as a second product conveying mechanism 703 and a transition plate 704 between the second product conveying mechanism 703 and the cutting area product conveying line 301, is arranged between the first product conveying line 400 and the cutting area product conveying line 301 in the same straight line in the circulation cutting device. The driving rod circulation mechanism 702 can adopt a circulation conveying mechanism, such as a chain or a belt circulation conveying device, to push the entire product group to the cutting start position C1 on the product group conveying path of the cutting area product conveying line 301, thereby more reliably ensuring the position and timing of entering the cutting start position C each time and better matching the cutting action. The driving rod circulation mechanism has a driving path starting from after the product blocking mechanism 401 to the cutting start position C. The driving rod 701 is circulated to the lower side of the rear end of the film-wrapped product group, pushes the product group to actively move forward along the driving path, and actively controls the product group to reach the cutting start position C.

[0038] The cutting mechanism circulation movement mechanism can adopt a belt or chain circulation conveying mechanism, and the cutting mechanism itself comprises a lifting mechanism connected to a mounting seat connected to the belt or chain circulation conveying mechanism, and the cutting working head 1 is arranged at the lower end of the lifting mechanism.

[0039] The cutting mechanism cycle movement mechanism 200 of the embodiment adopts a cross-shaped circulating conveyor belt as shown in the figure, and comprises a fixed seat 201, a horizontal guide rail is arranged on the fixed seat 201, and the horizontal two-end pulleys 202 of the cross-shaped circulating conveyor belt are arranged on the fixed seat 201, both of which are driving wheels and are driven by respective motors. The cutting mechanism is provided with a horizontal moving seat 203 and a vertical lifting frame 204, the horizontal moving seat 203 is slidably connected with the horizontal guide rail, a vertical guide rail is arranged on the horizontal moving seat 203, and the vertical moving frame 204 is slidably connected with the vertical guide rail, the horizontal moving seat 203 is arranged in a square shape and symmetrically located on both sides of the vertical lifting frame 204, four guide pulleys 205 are arranged on the horizontal moving seat 203, a top guide pulley 206 is arranged at the top end of the vertical lifting frame 204, a connecting structure 207 is arranged on both sides below the four guide pulleys 205, a cutter seat 208 is fixed at the bottom end of the vertical lifting frame 204, and the two ends of the circulating conveyor belt are connected with the connecting structures 207 on both sides and pass through the square-shaped guide pulleys 205, the two-end pulleys 202 and the top guide pulley 206 to form a cross shape, and through the forward rotation and reverse rotation of the motor, the cross-shaped circulating conveyor belt can move circularly and simultaneously move along the X and Y axes, for example, the oblique downward running track of the descending section can be very conveniently realized, and the efficiency is higher

[0040] Reference Figure 6 The working process of the present application is as follows:

[0041] S1, which can be regarded as the starting state of a round of cutting work or the ending state of a round of cutting work, at this time, the first cutting mechanism 101 completes the cutting work, the back end of the film-coated product 300 is sealed after being coated with the film, the upper film 601 and the lower film 602 are connected, the connection line 605 and the sealing line are disconnected, the connected film is straightened by the upper film tensioning mechanism 603 and the lower film tensioning mechanism 604 and located in front of the cutting starting position C, and waits for the next product group to enter;

[0042] S2 is the state when the front end of the product group is transported forward against the packaging film, at this time, the first cutting mechanism 101 has risen to give way, and the second cutting mechanism 102 has moved to the rear of the cutting starting position C;

[0043] S3 is connected with S2, the rear end of the product group is transported to the cutting starting position C, the second cutting mechanism 102 moves from the rear of the transported product group to the front and descends to the cutting starting position C, and starts the cutting work;

[0044] S4, while the film-coated product group is continuously transported forward without stopping, the second cutting mechanism simultaneously performs the cutting work.

[0045] Unless otherwise defined, all terms used in the disclosure, such as "upper", "lower", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", etc. indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the terms describing the orientation or positional relationship in the disclosure are only used for exemplary illustration, and cannot be understood as a limitation on the patent, and for those skilled in the art, the specific meaning of the above terms can be understood in combination with the drawings and according to the specific circumstances.

[0046] Unless otherwise specified and limited, in the disclosure, the terms "provided", "clamped" and "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the disclosure can be understood according to the specific circumstances.

[0047] The above is only a specific embodiment of the present application, but the structural features of the present application are not limited to this, any changes or modifications made by those skilled in the art within the scope of the present application are covered by the protection scope of the present application.

Claims

1. Circular sealing and cutting device, including a sealing and cutting mechanism, wherein the sealing and cutting mechanism is provided with a sealing and cutting working head, characterized in that The circulating sealing and cutting device further comprises a product conveying line in the sealing and cutting area, a sealing and cutting cushion strip and a circulating motion mechanism of the sealing and cutting mechanism. The sealing and cutting cushion strip is connected to the circulating conveying mechanism and is circulated and conveyed, and can be conveyed to the sealing and cutting starting position according to the sealing and cutting starting timing and conveyed forward as the film-wrapped product is conveyed forward, and is circulated back to the sealing and cutting starting position after the sealing and cutting work is completed. The sealing and cutting mechanism is connected to the circulating motion mechanism of the sealing and cutting mechanism and can be conveyed to the sealing and cutting starting position according to the sealing and cutting starting timing and conveyed forward as the product is conveyed forward, and sealing and cutting are completed during the forward conveying process. The running trajectory of the sealing and cutting working head includes a forward conveying section corresponding to the sealing and cutting work, a descending section before the sealing and cutting starting position, an ascending section after the forward conveying section, and a return section between the ascending section and the descending section. The cyclic sealing and cutting device is provided with at least two sets of sealing and cutting mechanisms that perform the hot sealing and cutting work in sequence, and the sealing and cutting mechanisms are provided on the cyclic motion mechanism of the sealing and cutting mechanism to realize the cyclic sealing and cutting action; The descending section is a trajectory that runs forward and downward step by step from the rear of the sealing and cutting starting position, including at least a second half of the descending section that runs obliquely forward and downward from the rear of the sealing and cutting starting position to the sealing and cutting starting position, or a trajectory that first runs forward from the rear of the sealing and cutting starting position to above the sealing and cutting starting position and then descends to the sealing and cutting starting position.

2. The cyclic sealing and cutting device according to claim 1, characterized in that The circulating sealing and cutting device is provided with two sets of sealing and cutting mechanisms that perform the hot-sealing and sealing work in an alternating manner, and the two sets of sealing and cutting mechanisms respectively have their own sealing and cutting mechanism circulating motion mechanisms.

3. The cyclic sealing and cutting device according to claim 2, characterized in that The sealing and cutting mechanism's respective circulating motion mechanisms are located on both sides of the conveying route of the film-wrapped product. The sealing and cutting working head is in the shape of a long arm, with its first end connected to the sealing and cutting mechanism on the side where its circulating motion mechanism is set, and its second end extends to the other side to match the width of the film. The two sets of sealing and cutting mechanisms operate in an interlaced manner without interfering with each other.

4. The cyclic sealing and cutting device according to claim 1, characterized in that The circulating conveying mechanism of the sealing and cutting gasket strip adopts the sealing and cutting area product conveying line, and the sealing and cutting gasket strip is located between the product supporting structures or on the product supporting structures on the sealing and cutting area product conveying line.

5. The cyclic sealing and cutting device according to claim 1, characterized in that The circulating conveying mechanism of the sealing and cutting gasket strip adopts a gasket strip circulating conveying mechanism outside the product conveying line in the sealing and cutting area. The gasket strip circulating conveying mechanism includes a conveying stroke that overlaps with the product conveying line in the sealing and cutting area. The overlapping stroke corresponds to the sealing and cutting starting position to the sealing and cutting end position, and in the overlapping stroke, the sealing and cutting gasket strip is located between the product support structures on the product conveying line in the sealing and cutting area or above the product support structures.

6. The cyclic sealing and cutting device according to claim 1, characterized in that The forward conveying section ends before the conveying end point of the product conveying line in the sealing and cutting area.

7. The cyclic sealing and cutting device according to claim 1, characterized in that A first product conveying line is provided before the product conveying line in the sealing and cutting area and is driven independently of the product conveying line in the sealing and cutting area. The first product conveying line is provided with a product blocking mechanism. The sealing and cutting starting position is located on the conveying path inside the product conveying line in the sealing and cutting area. The circulating sealing and cutting device is also provided with a driving mechanism, which includes a driving rod and a driving rod circulating mechanism. The circulating sealing and cutting device is provided with a conveying connection mechanism between the first product conveying line and the sealing and cutting area product conveying line. The driving rod circulating mechanism has a driving path, which starts from after the first product conveying line to the sealing and cutting starting position.

8. The film wrapping machine's cyclic sealing and cutting method has the following characteristics: At least two sets of sealing and cutting mechanisms are used to perform sealing and cutting work in sequence; the sealing and cutting mechanisms are provided with sealing and cutting working heads; The sealing and cutting work is performed within a travel range. Within this travel range, the sealing and cutting work of the film is performed by a sealing and cutting work head following the product, and the sealing and cutting work is performed during the following process. The running trajectory of the sealing and cutting work head includes a forward conveying section corresponding to the sealing and cutting work, a descending section before the sealing and cutting starting position, an ascending section after the forward conveying section, and a return section between the ascending section and the descending section. The cyclic sealing and cutting method includes the following processes: S1, the first sealing and cutting mechanism completes the sealing and cutting work, and the connected film is straightened by the upper film tensioning mechanism and the lower film tensioning mechanism, and is located before the sealing and cutting starting position, waiting for the next product group to enter S2: The front end of the product group is conveyed forward against the packaging film, the first sealing and cutting mechanism rises to make way, and the second sealing and cutting mechanism moves to the rear of the sealing and cutting starting position; S3, following S2, the rear end of the product group is conveyed to the sealing and cutting starting position, and the second sealing and cutting mechanism moves forward from the rear of the product group being conveyed and descends to the sealing and cutting starting position to perform the sealing and cutting work; S4, the product group is continuously conveyed forward, and at the same time, the second sealing and cutting mechanism performs the sealing and cutting work.

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