A drawstring bag sealing device

Abstract

This invention discloses a longitudinal sealing device for drawstring bags, including a first guide roller. The drawstring bag includes an upper half and a lower half of the bag opening, each with a folded edge, formed from a bag body film. It also includes a longitudinal sealing roller and an isolation pressure belt. A heating wire is provided around the circumference of the longitudinal sealing roller. The isolation pressure belt is positioned to match the heating wire and is placed between the folded edges of the upper and lower half of the bag opening. During heat sealing, the folded edge between the isolation pressure belt and the heating wire of the longitudinal sealing roller forms a heat-sealed joint with the corresponding upper or lower half of the bag opening. The longitudinal sealing speed is fast, heat loss from the heating wire is minimal, resulting in significant energy savings. Furthermore, the isolation pressure belt moves at the same speed as the bag body film, completely separating the upper and lower half of the bag opening, preventing mutual interference during heat sealing. This helps ensure the quality of subsequent conveying and transverse sealing, avoids waste bags, and allows for high production speed.

Description

Technical Field

[0001] This invention relates to the field of drawstring bag machinery technology, specifically a drawstring bag longitudinal sealing device. Background Technology

[0002] A drawstring bag is a type of packaging bag, typically consisting of a bag body and a drawstring. The drawstring, usually a plastic rope, is threaded through the bag opening. A notch is provided at the bag opening for easy removal of the drawstring. When filling the bag with materials, the drawstring is pulled through the notch, and the bag opening naturally tightens. Currently, drawstring bags are manufactured using mechanical equipment. The typical production process involves using a cylindrical bag film strip as raw material, first performing an M-shaped edge folding process, and then cutting the formed M-shaped edge structure along its central fold line. Figure 4 As shown, the bag opening consists of an upper half and a lower half with folded edges 17. The other side of the continuous strip is the bag bottom 18. A plastic rope 15 is then inserted through the folded edges 17. The folded edges 17 are then longitudinally heat-sealed to form a cavity 16, allowing the plastic rope 15 to slide freely within the cavity. Finally, the bag is horizontally sealed and cut into individual drawstring bags. Because the bag opening has an overlapping structure with upper and lower halves, to avoid the upper and lower halves from sticking together during longitudinal sealing, the existing technology typically... The upper and lower halves of the bag opening are often separated and then paired heat-sealing rollers are used to complete the longitudinal heat sealing. This makes the travel path of the strip at the bag opening longer than that at the bottom of the bag at the same position. During bag making, the strip at the bag opening is prone to stretching. After longitudinal sealing, wrinkles are likely to occur, which may even affect subsequent conveying and correction work. Waste bags will be produced during transverse sealing and cutting. At the same time, since the heat-sealing rollers are in line contact, the effective heating surface in the longitudinal direction is small during longitudinal sealing, resulting in slow production speed and poor energy efficiency. Summary of the Invention

[0003] The purpose of this invention is to provide a longitudinal sealing device for a drawstring bag to solve the problems in the prior art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a longitudinal sealing device for a drawstring bag, comprising a first guide roller 2, wherein the drawstring bag comprises an upper half of the bag opening and a lower half of the bag opening formed from a bag body film 1, each having a folded edge 17, and further comprising a longitudinal sealing roller 6 and an isolation pressure belt 4, wherein an electric heating wire 7 is provided on the circumference of the longitudinal sealing roller 6, and at least one section of the isolation pressure belt 4 is placed between the folded edges 17 of the upper half of the bag opening and the lower half of the bag opening and is adapted to the position of the electric heating wire 7; during heat sealing, the folded edge 17 between the isolation pressure belt 4 and the electric heating wire 7 of the longitudinal sealing roller 6 forms a heat-sealed joint 19 with the corresponding upper half of the bag opening or the lower half of the bag opening.

[0005] Furthermore, the isolation belt 4 is a seamless annular belt structure.

[0006] Furthermore, the drawstring bag sealing device also includes a guide assembly for guiding the isolation pressure belt 4. The guide assembly includes guide plates 3 respectively disposed at the feed end and discharge end of the longitudinal sealing roller 6, and a second guide roller 5 corresponding to each guide plate 3. The guide plate 3 has a guide slope 301 at one end facing the bag film 1. The isolation pressure belt 4 runs along the path formed by the guide slope 301 at the feed end of the longitudinal sealing roller 6, the working arc segment of the longitudinal sealing roller 6, the guide slope 301 at the discharge end, and the second guide roller 5. The guide slope 301 is used to introduce or exit the isolation pressure belt 4 into or out of the bag film 1 area. The isolation pressure belt 4 has the same linear velocity as the bag film 1.

[0007] Furthermore, the isolation strip 4 is a Teflon strip.

[0008] Furthermore, the longitudinal sealing roller 6 includes a roller 601 fixed on a rotating shaft 11 and an insulating ring 8 pressed onto the roller 601 by an extension sleeve 9. An electric slip ring 12 is installed at one end of the rotating shaft 11. The heating wire 7 is fixed in a ring on the outer surface of the insulating ring 8 and passes through the insulating ring 8 from end to end, and is electrically connected to the output end of the electric slip ring 12. The input end of the electric slip ring 12 is connected to a power source.

[0009] Furthermore, the side of the heating wire 7 facing the bag film 1 is covered with an anti-stick layer 13, which is a fiberglass cloth tape or a Teflon tape.

[0010] The beneficial effects of this invention are as follows: The longitudinal sealing device for drawstring bags provided by this invention uses a seamless annular belt structure made of Teflon tape as an isolation pressure belt. On the one hand, it presses the half of the bag opening and the folded edge that needs to be heat-sealed against the heating wire. During longitudinal heat sealing, the effective heating path is long and the area is large. Therefore, the longitudinal sealing speed is fast, the heat loss of the heating wire is small, and the energy-saving effect is obvious. Moreover, the isolation pressure belt moves at the same speed as the bag film, that is, the isolation pressure belt and the bag film are relatively stationary, completely separating the upper half and the lower half of the bag opening. During longitudinal heat sealing, the upper half and the lower half of the bag opening will not affect each other, avoiding adhesion and ensuring the quality of the bag opening. At the same time, because the isolation pressure belt is thin, the distance between the upper half and the lower half of the bag opening is small, which does not affect the tape material. This is beneficial to ensuring the quality of subsequent conveying and transverse sealing and cutting, avoiding waste bags, and the production speed is fast. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the structure of the present invention;

[0012] Figure 2 This is a schematic diagram of the longitudinal sealing roller structure of the present invention;

[0013] Figure 3 for Figure 2Enlarged view of a portion of point A in the middle;

[0014] Figure 4 This is a schematic diagram of the longitudinal sealing steps of the drawstring bag according to the present invention;

[0015] Figure 5 This is a schematic diagram of another embodiment of the present invention. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] Please see Figure 1-4 A drawstring bag sealing device includes a first guide roller 2. The drawstring bag includes an upper half and a lower half of the bag opening, each having a folded edge 17, formed from a bag body film 1. The device also includes a sealing roller 6 and an isolation pressure belt 4. The sealing roller 6 has a heating wire 7 on its circumference. At least one section of the isolation pressure belt 4 is placed between the folded edges 17 of the upper and lower half of the bag opening and is adapted to the position of the heating wire 7. During heat sealing, the folded edge 17 between the isolation pressure belt 4 and the heating wire 7 of the sealing roller 6 forms a heat-sealed joint 19 with the corresponding upper or lower half of the bag opening. Here, the isolation pressure belt 4 is a seamless annular belt structure, preferably a Teflon belt.

[0018] In a preferred embodiment, the drawstring bag sealing device further includes a guiding assembly for guiding the isolation pressure belt 4. The guiding assembly includes guide plates 3 respectively located at the feed end and discharge end of the sealing roller 6, and a second guide roller 5 corresponding to each guide plate 3. One end of the guide plate 3 facing the bag film 1 has a guiding slope 301. The isolation pressure belt 4 runs along the path formed by the guiding slope 301 at the feed end of the sealing roller 6, the working arc segment of the sealing roller 6, the guiding slope 301 at the discharge end, and the second guide roller 5. The guiding slope 301 is used to introduce or exit the isolation pressure belt 4 into or out of the bag film 1 area. The isolation pressure belt 4 has the same linear velocity as the bag film 1. In this process, the angle between the guide slope 301 and the running direction of the bag film 1 is preferably 45 degrees. The second guide roller 5 is installed vertically. Thus, during operation, after the folded edges 17 of the upper and lower halves of the bag opening are formed and the plastic rope 15 is inserted, the bag film 1 is pulled by the traction mechanism (not shown) of the drawstring bag making machine and introduced into the longitudinal sealing roller 6 by the first guide roller 2 located at the feeding end. The folded edges 17 of the upper and lower halves of the bag opening that need to be longitudinally heat-sealed coincide with the position of the heating wire 7. At this time, the guide plate 3 located at the feeding end of the longitudinal sealing roller 6 and inserted into the upper and lower halves of the bag opening guides the isolation pressure belt 4 to turn through its guide slope 301. After being inserted at 90 degrees, the strip is guided between the folded edges 17 of the upper and lower halves of the bag opening, thus separating the folded edges 17 of the upper and lower halves of the bag opening. Under the friction of the bag film 1, the isolation pressure belt 4 enters the working arc section of the longitudinal sealing roller 6 synchronously with the bag film 1. At this time, the isolation pressure belt 4 presses the corresponding folded edges 17 and the bag film 1 with the heating wire 7. The heat generated by the heating wire 7 completes the heat sealing of the folded edges 17 and the bag film 1 (at the corresponding upper or lower half of the bag opening) to form a heat-sealed joint 19, thereby forming a longitudinal cavity 16 that accommodates and allows the plastic rope 15 to slide. When the isolation pressure belt 4 leaves... After the working arc of the longitudinal sealing roller 6, the material is guided by the guide plate 3 at the discharge end of the longitudinal sealing roller 6 to turn 90 degrees away from the area of ​​the bag film 1, and then guided by the second guide roller 5 to the guide plate 3 at the feed end of the longitudinal sealing roller 6 to enter the bag film 1. This cycle continues. Here, there are two second guide rollers 5 and two guide plates 3. The pressure of the isolation belt 4 on the bag film 1 can be adjusted by adjusting the tension of the isolation belt 4 through the second guide roller 5. The tension adjustment can adopt the existing tension adjustment technology. Alternatively, a transmission device can be connected to one of the second guide rollers 5 to drive the isolation belt 4 and the bag film 1 to run actively at the same linear speed.

[0019] In a preferred embodiment, the longitudinal sealing roller 6 includes a roller 601 fixed on a rotating shaft 11 and an insulating ring 8 pressed onto the roller 601 by an extension sleeve 9. One end of the rotating shaft 11 is equipped with an electric slip ring 12, and the other end of the rotating shaft 11 is connected to a transmission device. The heating wire 7 is fixed annularly on the outer surface of the insulating ring 8, and the heating wire 7 passes through the insulating ring 8 and is electrically connected to the output end of the electric slip ring 12. The input end of the electric slip ring 12 is connected to a power source. Specifically, both ends of the rotating shaft 11 are mounted on the wall plate 10 of the drawstring bag making machine through bearings. The extension sleeve 9 is provided with a journal, and the insulating ring 8 is mounted on the journal. The extension sleeve 9 is mounted on the roller 601 near the end of the electric slip ring 12 by fasteners 14, thereby pressing the insulating ring 8 onto the roller 601.

[0020] refer to Figure 1 In this embodiment, two longitudinal sealing rollers 6 are set on the travel path of the bag film 1. Each longitudinal sealing roller 6 is independently equipped with an isolation pressure belt 4. The first longitudinal sealing roller 6 completes the setting position of the folded edge 17 of the upper half of the bag opening and longitudinally heat seals the bag film 1. The second longitudinal sealing roller 6 continues to complete the setting position of the folded edge 17 of the lower half of the bag opening and longitudinally heat seals the bag film 1. After longitudinal heat sealing, the bag film 1 is discharged and transported to the subsequent station by the first guide roller 2 at the discharge end. The second longitudinal sealing roller 6 and the first longitudinal sealing roller 6 are arranged at different heights, making the overall structure compact, reducing the area occupied, and increasing production efficiency.

[0021] refer to Figure 5 As a further preferred embodiment, this embodiment sets two longitudinal sealing rollers 6 and a paired isolation pressure belt 4 on the travel path of the bag film 1. The isolation pressure belt 4 is introduced from the feed end of the first longitudinal sealing roller 6, completes the setting position of the folded edge 17 of the upper half of the bag opening and longitudinally heat seals the bag film 1, and continues to advance with the bag film 1 to the second longitudinal sealing roller 6 to complete the setting position of the folded edge 17 of the lower half of the bag opening and longitudinally heat seal the bag film 1. Then, it is discharged from the discharge end of the second longitudinal sealing roller 6 through the guide plate 3 and then through the second guide roller 5 to form a closed loop. After longitudinal heat sealing, the bag film 1 is discharged from the first guide roller 2 at the discharge end and transported to the subsequent station. Compared with the previous embodiment, this embodiment further saves the number of isolation pressure belts 4 and second guide rollers 5.

[0022] In a preferred embodiment, the side of the heating wire 7 facing the bag film 1 is covered with an anti-adhesive layer 13, which is a fiberglass cloth tape or Teflon tape. This layer prevents the bag film 1 from sticking and burning the heating wire 7 during heat sealing and also provides insulation.

[0023] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the term "comprising," or any other variation thereof, is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0024] In the description of this invention, it should be understood that the terms "upper half", "lower half", "one end", "the other end", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0025] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A drawstring bag sealing device, comprising a first guide roller (2), wherein the drawstring bag comprises an upper half of the bag opening and a lower half of the bag opening, each having a folded edge (17), formed from a bag body film (1), characterized in that: It also includes a longitudinal sealing roller (6) and an isolation pressure belt (4). The longitudinal sealing roller (6) is provided with an electric heating wire (7) on its circumference. At least one section of the isolation pressure belt (4) is placed between the folded edge (17) of the upper half of the bag opening and the lower half of the bag opening and is adapted to the position of the electric heating wire (7). When the heat sealing is working, the folded edge (17) between the isolation pressure belt (4) and the electric heating wire (7) of the longitudinal sealing roller (6) forms a heat-sealed joint (19) with the corresponding upper half or lower half of the bag opening. The isolation strip (4) is a seamless annular strip structure; It also includes a guide assembly for guiding the isolation pressure belt (4), the guide assembly including guide plates (3) respectively provided at the feed end and discharge end of the longitudinal sealing roller (6) and a second guide roller (5) corresponding to each guide plate (3), the guide plate (3) is provided with a guide slope (301) at one end facing the bag film (1), the isolation pressure belt (4) runs along the path formed by the guide slope (301) at the feed end of the longitudinal sealing roller (6), the working arc segment of the longitudinal sealing roller (6), the guide slope (301) at the discharge end and the second guide roller (5), the guide slope (301) is used to introduce or exit the isolation pressure belt (4) into the area of ​​the bag film (1), the isolation pressure belt (4) has the same linear velocity as the bag film (1).

2. The longitudinal sealing device for a drawstring bag according to claim 1, characterized in that: The isolation strip (4) is a Teflon strip.

3. The longitudinal sealing device for a drawstring bag according to claim 1, characterized in that: The longitudinal sealing roller (6) includes a roller (601) fixed on a rotating shaft (11) and an insulating ring (8) pressed on the roller (601) by an extension sleeve (9). An electric slip ring (12) is installed at one end of the rotating shaft (11). The electric heating wire (7) is fixed in a ring on the outer surface of the insulating ring (8) and the electric heating wire (7) passes through the insulating ring (8) and is electrically connected to the output end of the electric slip ring (12). The input end of the electric slip ring (12) is connected to a power source.

4. The longitudinal sealing device for a drawstring bag according to claim 3, characterized in that: The heating wire (7) facing the bag film (1) is covered with an anti-stick layer (13), which is a fiberglass cloth tape or a Teflon tape.

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