A film heat press compounding device

Abstract

The utility model discloses a film hot press composite device, its technical scheme main points include film conveying roller group one, film conveying roller group two and two groups of hot press mechanism, film conveying roller group one is used for conveying film one to hot press mechanism, film conveying roller group two is used for conveying film two to hot press mechanism, and two groups of hot press mechanism are along the membrane material delivery direction setting, are used for to film one and film two hot press composite, and hot press mechanism includes upper hot press roller, lower hot press roller and support frame, and upper hot press roller sliding installation is in support frame, and lower hot press roller rotates and installs in support frame, and upper hot press roller is located in the just above lower hot press roller, and upper hot press roller and lower hot press roller periphery are equipped with a plurality of upper convex ring and lower convex ring respectively, and upper convex ring and lower convex ring press each other, can carry out hot press composite to film one and film two, and two groups of hot press mechanism can be relatively slip adjustment. The utility model has integrated filling and composite film, and the effect of different width's stripe can be adjusted and pressed together.

Description

Technical Field

[0001] This utility model relates to the field of thin film composite processing, and more specifically, to a thin film hot pressing composite device. Background Technology

[0002] A film hot-pressing lamination unit is an automated device used to manufacture multilayer composite film materials. It is a key piece of equipment in materials processing, particularly in industries such as flexible packaging, medical protective equipment, and new energy battery separators.

[0003] For some membrane materials, it is necessary to heat-press two layers of film together and fill the space between the two membranes with some flocculent or foam-like filler, so that the membrane material as a whole has a relatively fluffy effect, which can be used as a packaging material to protect and cushion the packaged items.

[0004] One type of membrane material requires composite processing of two membrane materials on both sides. The two layers of film are hot-pressed together using a hot-pressing composite device. The hot-pressed texture is striped along the length of the membrane material, creating a certain unpressed gap in the middle of the membrane material, which can be filled with a buffer material.

[0005] By setting convex rings on the outer periphery of the hot press rollers, with the convex rings of the upper and lower hot press rollers facing each other, heat can be concentrated at the pressing position of the convex rings, enabling striped hot press lamination of the membrane material. The texture of the hot press lamination on the membrane surface is directly determined by the width of the convex rings on the outer periphery of the hot press rollers. Therefore, the width of the hot press lamination texture cannot be easily adjusted and can only be achieved by replacing hot press rollers of different sizes.

[0006] Therefore, a new solution is needed to address this problem. Utility Model Content

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a thin film hot pressing composite device, which has the effect of integrated filling and composite film, and adjustable pressing to produce stripes of different widths.

[0008] To achieve the above objectives, this utility model adopts the following technical solution: a film hot-pressing laminating device, comprising a first film conveying roller group, a second film conveying roller group, and two sets of hot-pressing mechanisms. The first film conveying roller group is used to convey film one to the hot-pressing mechanism; the second film conveying roller group is used to convey film two to the hot-pressing mechanism; the two sets of hot-pressing mechanisms are arranged along the film conveying direction and are used for hot-pressing laminating film one and film two; the hot-pressing mechanism includes an upper hot-pressing roller, a lower hot-pressing roller, and a support frame, wherein the upper hot-pressing roller is slidably mounted on the support frame. The lower hot press roller is rotatably mounted on the support frame. The upper hot press roller is located directly above the lower hot press roller, and both ends of the upper hot press roller are rotatably supported by slide blocks, which are disposed on the support frame. The outer circumference of the upper and lower hot press rollers are respectively provided with a plurality of upper and lower convex rings, which are arranged one-to-one corresponding to each other. The upper and lower convex rings press against each other, enabling hot pressing and laminating of film one and film two. The support frame is slidably mounted on the machine frame along the axial direction of the upper hot press roller, and the two sets of hot pressing mechanisms can slide and adjust relative to each other.

[0009] By adopting the above scheme, the support frames of the two sets of hot pressing mechanisms can slide on the frame along the axis of the upper hot pressing roller, allowing the equipment to adjust the lateral spacing between the two sets of hot pressing units according to production needs. This design enables the device to no longer be limited to producing pressing stripes of a single width, but can efficiently and quickly press composite stripes of various widths, greatly enhancing the equipment's production flexibility and process adaptability. Simultaneously, the convex ring structure mating on the upper and lower hot pressing rollers ensures the quality and consistency of the hot pressing composite.

[0010] The present invention is further configured such that the widths of the upper convex ring and the lower convex ring are the same, and in the two sets of hot pressing mechanisms, the indentations of the upper convex ring and the lower convex ring at least partially overlap.

[0011] By adopting the above scheme, and designing the upper and lower convex rings in the two sets of hot pressing mechanisms to have the same width and ensuring that their indentations at least partially overlap, the composite quality and functional flexibility of the device are improved. This structure ensures that during continuous pressing, the two indentations can be aligned or form a controllable overlap area, which not only effectively enhances the composite strength of the stripe edges but also avoids the generation of unpressed gaps.

[0012] The present invention is further configured such that the distance between the two sets of hot pressing mechanisms that can slide relative to each other is less than the width of the upper convex ring.

[0013] By adopting the above scheme, and limiting the relative sliding adjustment distance of the two sets of hot pressing mechanisms to less than the width of the upper convex ring, the continuity of the pressing process and the reliability of the composite quality are ensured. This design allows the two indentations to maintain partial overlap when adjusting the stripe width, effectively avoiding unpressed blank areas due to excessive adjustment gaps. This controllable overlapping pressing not only strengthens the interfacial bonding force but also enables the composite film to maintain structural integrity while achieving a smooth transition in stripe width and uniform stress distribution, thus improving the product's sealing performance and mechanical stability.

[0014] The present invention is further configured such that the support frame has vertically extending grooves on both sides, the slide block is slidably installed in the grooves, the upper end of the slide block is connected to a lifting rod, and the lifting rod is connected to a driving device for driving the upper hot press roller to move up and down along the grooves.

[0015] By adopting the above solution, and through the coordinated design of the chute, slide block, and lifting rod, stable vertical lifting motion of the upper hot press roller is achieved. This allows the equipment to quickly adjust the hot pressing gap and pressure according to the material and thickness of the film. This not only ensures the bonding quality required for different products and avoids poor lamination or film damage caused by uneven pressure, but also improves the equipment's process adaptability and ease of operation for different production tasks.

[0016] The present invention is further configured such that a transverse drive rod is externally connected to the support frame, and the transverse drive rod is connected to a transverse drive device for driving the hot pressing mechanism to slide along the axial direction and for adjusting the relative transverse spacing between the upper and lower sets of convex rings.

[0017] By adopting the above solution, the combination of the lateral drive rod and the drive device endows the core component with axial position control capability. This design allows the two sets of hot pressing mechanisms to slide relative to each other according to production instructions, thereby adjusting the lateral spacing between the upper and lower convex rings. This enables the equipment to quickly adapt to the production needs of products of different specifications without replacing any hardware, and can efficiently press out composite stripes of various widths and distribution patterns, greatly improving the equipment's functional versatility.

[0018] The present invention is further configured to include a filler conveying roller group, which is located between the first film conveying roller group and the second film conveying roller group, and is used to convey filler between the first film and the second film.

[0019] By adopting the above scheme and introducing a filler conveyor roller group located between the two films, functional interlayer materials such as fiber webs and non-woven fabrics can be simultaneously fed between the two films and enter the hot-pressing zone together for lamination. This achieves the integration of the two processes of "interlayer filling" and "hot-pressing lamination," which not only simplifies the production process but also successfully manufactures functional composite membrane products with specific interlayer structures (such as reinforcement, filtration, and sound absorption), ensuring the uniformity and integrity of the interlayer bonding.

[0020] The present invention is further configured such that the filler is a flocculent material with a strip-like structure, and each filler is arranged side by side evenly along the width direction and corresponds to the gap between the upper convex rings.

[0021] By adopting the above scheme, using a strip-shaped flocculent material as the filler, and arranging it evenly side-by-side along the width direction, while aligning it with the gaps between the upper convex rings, a high degree of synergy between structural design and process requirements is achieved. This configuration allows the filler to be embedded in the gaps between the stripes formed by hot pressing, fully utilizing the fluffy, breathable, or sound-absorbing properties of the flocculent material, while ensuring the integrity of the composite membrane through the pressing of the convex rings.

[0022] The present invention is further configured such that an upper pressing block is provided on the outer periphery of the upper hot pressing roller; a lower pressing block is provided on the outer periphery of the lower hot pressing roller, and the upper pressing block and the lower pressing block can press against each other during the rotation of the upper and lower hot pressing rollers; the upper pressing block is located between two upper convex rings, and the lower pressing block is located between two lower convex rings.

[0023] By adopting the above scheme, an upper and lower pressure block are added to the outer periphery of the upper and lower hot press rollers, and positioned between the two upper and lower convex rings, respectively, a composite pressing mode is constructed. This design allows the device to form continuous sealing stripes through the pressing of the convex rings during continuous rotation, while also utilizing the intermittent pressure of the upper and lower pressure blocks to form independent point-like or strip-like pressing points in specific areas between the stripes. This synergistic effect enhances the interlayer bonding force of the composite film in non-striped areas.

[0024] The present invention is further configured such that the upper pressing block has an upper pressing surface, which is flush with the outermost contour surface of the upper convex ring; the lower pressing block has a lower pressing surface at its top, which is tangent to the inner surface of the outer edge of the lower convex ring; the upper pressing surface and the lower pressing surface can press against each other.

[0025] By adopting the above scheme, and by setting the upper pressing surface of the upper pressure block to be flush with the outermost contour of the upper convex ring, while simultaneously making the lower pressing surface of the lower pressure block tangent to the inner surface of the outer edge of the lower convex ring, a seamless connection in pressure distribution between the convex ring pressing and the pressure block pressing is achieved. This design enables the two pressing structures to form a continuous and uniform stress interface during operation, ensuring the integrity of the sealing stripes through the convex ring pressing and enhancing the bonding force in the stripe gap area through the pressure block pressing.

[0026] In summary, this utility model has the following beneficial effects:

[0027] 1. By driving two sets of hot pressing units to move independently or synchronously along the axial direction of the pressure rollers, the lateral spacing between them can be adjusted. This design breaks through the limitation of traditional equipment that can only produce products of a single specification, allowing operators to set and press out composite stripes of different widths according to process requirements without changing molds or stopping the machine for complex mechanical adjustments, greatly enhancing the processing flexibility of the equipment.

[0028] 2. By setting an optimized filler guiding and conveying path between the upper and lower film layers and the hot pressing mechanism, the positioning and synchronous conveying of the filler material are achieved. This integrated design allows the two originally separate processes of "filler insertion" and "hot pressing composite stripes" to be completed in one continuous process, which not only simplifies the equipment structure and operation process, but also improves material utilization and overall production efficiency. Attached Figure Description

[0029] Figure 1 This is a cross-sectional view of a thin film hot-pressing composite device in this embodiment;

[0030] Figure 2 This is a perspective view of the hot pressing mechanism in this embodiment;

[0031] Figure 3 This is a top view of the hot pressing mechanism in this embodiment;

[0032] Figure 4 This is a cross-sectional view of the hot pressing mechanism in this embodiment;

[0033] Figure 5 This is a cross-sectional view of the composite membrane in this embodiment;

[0034] Figure 6 This is a cross-sectional view of the upper and lower hot press rollers in this embodiment;

[0035] Figure 7 for Figure 4 Enlarged view of point A in the middle.

[0036] Reference numerals: Film conveying roller group 1; Film 101; Film conveying roller group 2; Film 21; Filler conveying roller group 3; Filler 31; Stripe 32; Composite film 41; Rewinding roller 5; Hot pressing mechanism 6; Upper hot pressing roller 61; Upper convex ring 611; Upper pressure block 612; Upper pressing surface 6121; Spacing groove 613; Lower hot pressing roller 62; Lower convex ring 621; Lower pressure block 622; Lower pressing surface 6221; Support frame 7; Slide 71; Lifting rod 72; Slide groove 73; Lateral drive rod 8. Detailed Implementation

[0037] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0038] This embodiment discloses a thin film hot-pressing lamination device, referring to... Figures 1-7 As shown, it includes a film conveying roller group 1, a film conveying roller group 2, a filler conveying roller group 3, a take-up roller 5, and two parallel hot pressing mechanisms 6. The film conveying roller group 1 and the film conveying roller group 2 are rotatably mounted on the upper and lower parts of the frame, respectively, and each includes several guide rollers, which can guide and convey the film material. The film conveying roller group 1 can convey film 101 to the hot pressing mechanism 6, and the film conveying roller group 2 can convey film 21 to the hot pressing mechanism 6.

[0039] Two sets of hot pressing mechanisms 6 are arranged along the film material conveying direction, which can perform hot pressing composite of film one 101 and film two 21 to form two hot pressing composite steps; the filler conveying roller group 3 is set between the two films, which can introduce the filler 31 and sandwich it between the two films; the composite film 41 after composite is finally wound up by the winding roller 5.

[0040] Reference Figure 2 As shown, the hot pressing mechanism 6 includes an upper hot pressing roller 61, a lower hot pressing roller 62, and a support frame 7. The lower hot pressing roller 62 is rotatably mounted on the support frame 7 via a rotating shaft. The upper hot pressing roller 61 is located directly above the lower hot pressing roller 62, and both ends of the upper hot pressing roller 61 are mounted on a slide block 71 via rotating shafts and are rotatably supported by the slide block 71.

[0041] The slide block 71 is disposed on both sides of the support frame 7. The support frame 7 has vertically extending grooves 73 on both sides. The slide block 71 is slidably installed in the grooves 73. The upper end of the slide block 71 is connected to a lifting rod 72. The lifting rod 72 is connected to the driving device and can drive the upper hot pressure roller 61 to move up and down along the grooves 73, changing the gap between the upper hot pressure roller 61 and the lower hot pressure roller 62, so as to control the film to pass through and adjust the pressure.

[0042] Reference Figure 2 , Figure 3 As shown, the outer periphery of the upper hot pressing roller 61 and the lower hot pressing roller 62 is provided with a plurality of upper convex rings 611 and lower convex rings 621, respectively. The upper convex rings 611 and lower convex rings 621 have the same width and are arranged one above the other, allowing them to press against each other to press film one 101 and film two 21 together. The upper hot pressing roller 61 and the lower hot pressing roller 62 can be heated by electricity or by heat transfer oil. Once the heating reaches a certain stability, the heat generated by the upper hot pressing roller 61 and the lower hot pressing roller 62 will be transferred to the upper convex rings 611 and the lower convex rings 621, heating the pressing position of the film material to achieve hot pressing lamination of the film.

[0043] The upper hot press roller 61 is driven downward by the lifting rod 72. The upper convex ring 611 and the lower convex ring 621 are heated and press against each other, thereby hot pressing out the stripes 32 of the required specifications. In the two sets of hot pressing mechanisms 6, the indentations of the upper convex ring 611 and the lower convex ring 621 at least partially overlap, which can form a relatively wide hot pressing pattern. The specific width range of the hot pressing pattern is between 1 and 2 times the width of the upper convex ring 611. When the patterns of the two hot pressings completely overlap, it is exactly the width of the upper convex ring 611 (at this time, only one set of two hot pressing mechanisms 6 can work). When the patterns of the two hot pressings partially overlap and partially misalign, the width of the hot pressing pattern is greater than the width of the stripe 32 of the upper convex ring 611, and the widest value is exactly twice the width of the upper convex ring 611.

[0044] By designing the upper convex ring 611 and lower convex ring 621 in the two sets of hot pressing mechanisms 6 to have the same width and to make their indentations at least partially overlap, the composite quality and functional flexibility of the device are improved. This structure ensures that during continuous pressing, the two indentations can be aligned or form a controllable overlap area, which not only effectively enhances the composite strength of the stripe 32 edge but also avoids the generation of unpressed gaps.

[0045] Reference Figure 3 , Figure 4As shown, a transverse drive rod 8 is externally connected to the support frame 7. The transverse drive rod 8 is connected to a transverse drive device. A slide rail is provided at the bottom of the hot pressing mechanism 6. The transverse drive device can drive the transverse drive rod 8, thereby driving the hot pressing mechanism 6 to slide along the slide rail axially, thus adjusting the relative transverse distance between the two sets of upper convex rings 611 and lower convex rings 621. In particular, the distance that the two sets of hot pressing mechanisms 6 can slide relative to each other is less than the width of the upper convex ring 611. By adjusting the transverse distance, the hot pressing mechanism 6 can hot press various specifications of stripes 32 on the film with a width between the width of the upper convex ring 611 and twice the width of the upper convex ring 611, realizing multiple uses of one machine and improving the applicability and production flexibility of the equipment.

[0046] To further enhance the interlayer bonding force of the composite film, an upper pressure block 612 is provided on the outer periphery of the upper hot pressure roller 61; a lower pressure block 622 is provided on the outer periphery of the lower hot pressure roller 62. During the rotation of the upper hot pressure roller 61 and the lower hot pressure roller 62, the upper pressure block 612 and the lower pressure block 622 can press against each other; the upper pressure block 612 is located between two upper convex rings 611, and the lower pressure block 622 is located between two lower convex rings 621.

[0047] By setting up an upper pressure block 612 and a lower pressure block 622, and positioning them between the two upper convex rings 611 and the lower convex ring 621 respectively, a composite pressing mode is constructed. This design allows the upper pressure block 612 and the lower pressure block 622 to press against each other during the rotation of the roller, forming a dotted or striped reinforced pressing structure in the area between the stripes 32. This not only forms continuous sealing stripes 32 through the pressing of the convex rings, but also utilizes the intermittent pressure of the upper and lower pressure blocks to form independent dotted or striped pressing points in specific areas between the stripes 32.

[0048] Reference Figure 6 , Figure 7 As shown, the upper pressure block 612 is provided with an upper pressure surface 6121, which is flush with the outermost contour surface of the upper convex ring 611. The lower pressure block 622 is provided with a lower pressure surface 6221 at its top, which is tangent to the inner surface of the outer edge of the lower convex ring 621. The upper pressure surface 6121 and the lower pressure surface 6221 can press against each other, realizing a seamless connection between the convex ring pressing and the pressure block pressing in terms of pressure distribution, ensuring that the composite film is pressed evenly as a whole, without stress concentration or pressing blind spots.

[0049] By setting the upper pressing surface 6121 of the upper pressing block to be flush with the outermost contour of the upper convex ring 611, and making the lower pressing surface 6221 of the lower pressing block 622 tangent to the inner surface of the outer edge of the lower convex ring 621, the pressing of the convex ring and the pressing of the pressing block can be made to abut against each other at one point, and the area between two adjacent stripes 32 is periodically and intermittently pressed to ensure the composite quality of the composite film.

[0050] By setting the upper pressing surface 6121 of the upper pressure block 612 to be flush with the outermost contour of the upper convex ring 611, and simultaneously making the lower pressing surface 6221 of the lower pressure block 622 tangent to the inner surface of the outer edge of the lower convex ring 621, during the rotation of the upper hot pressing roller 61 and the lower hot pressing roller 62, the lower pressing surface 6221 of the lower pressure block 622 will pass over the surface of the upper pressing surface 6121 of the upper pressure block 612. Extrusion can be formed at the rolling contact position, thereby applying hot pressure to the two layers of film and the filler 31 in between, so that a supplementary hot pressing composite can be formed at this position, and intermittent hot pressing can also be formed at the position between the two hot pressing lines, ensuring the stability of the filler 31 between the two layers of film.

[0051] Reference Figure 1 , Figure 2 and Figure 5 As shown, the filler conveying roller group 3 is installed between the two film input paths. The filler conveying roller group 3 can convey filler 31 between film one 101 and film two 21. The filler 31 is a fibrous flocculent material with a strip structure. Each filler 31 is arranged side by side evenly along the width direction and corresponds to the gap groove 613 between the upper convex ring 611 to ensure that the filler is guided to the designated pressing position. After film one 101, film two 21 and filler 31 are hot-pressed together, a continuous composite film 41 is formed. The composite film 41 is conveyed to the take-up roller 5 by the guide roller and is wound up by the take-up roller 5.

[0052] This device integrates filler delivery and hot-pressing composite functions, setting up an optimized filler guidance and delivery path between the upper and lower film layers and the hot-pressing mechanism 6. This enables integrated continuous production of sandwich filling and stripe 32 pressing. This integrated design allows the two originally separate processes of "inserting filler 31" and "hot-pressing composite stripe 32" to be completed in one continuous process. This not only simplifies the process and improves production efficiency but also expands the functionality and application range of the composite film, making it suitable for the flexible manufacturing of various high-performance composite film materials.

[0053] The above description is merely a preferred embodiment of this utility model. The protection scope of this utility model is not limited to the above embodiments. All technical solutions falling within the scope of this utility model's concept are protected. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of this utility model should also be considered within the protection scope of this utility model.

Claims

1. A thin-film hot-pressing composite device, characterized in that, The device includes a film conveying roller group one (1), a film conveying roller group two (2), and two sets of hot pressing mechanisms (6). The film conveying roller group one (1) is used to convey film one (101) to the hot pressing mechanism (6); the film conveying roller group two (2) is used to convey film two (21) to the hot pressing mechanism (6); the two sets of hot pressing mechanisms (6) are arranged along the film conveying direction and are used to hot press film one (101) and film two (21) together. The hot pressing mechanism (6) includes an upper hot pressing roller (61), a lower hot pressing roller (62) and a support frame (7). The upper hot pressing roller (61) is slidably mounted on the support frame (7), and the lower hot pressing roller (62) is rotatably mounted on the support frame (7). The upper hot pressing roller (61) is located directly above the lower hot pressing roller (62), and both ends of the upper hot pressing roller (61) are rotatably supported by slide blocks (71). The slide blocks (71) are provided on the support frame (7). The upper hot press roller (61) and the lower hot press roller (62) are respectively provided with a plurality of upper convex rings (611) and lower convex rings (621) on their outer periphery. The upper convex rings (611) and lower convex rings (621) are arranged in a one-to-one correspondence. The upper convex rings (611) and lower convex rings (621) press against each other, which can hot press the first film (101) and the second film (21) together. The support frame (7) is slidably installed on the machine frame along the axial direction of the upper hot press roller (61), and the two sets of hot press mechanisms (6) can slide and adjust relative to each other.

2. The thin-film hot-pressing composite device according to claim 1, characterized in that, The upper convex ring (611) and the lower convex ring (621) have the same width, and in the two sets of hot pressing mechanisms (6), the indentations of the upper convex ring (611) and the lower convex ring (621) at least partially overlap.

3. The thin-film hot-pressing composite device according to claim 1, characterized in that, The distance that the two sets of hot pressing mechanisms (6) can slide relative to each other is less than the width of the upper convex ring (611).

4. The thin film hot pressing composite device according to claim 1, characterized in that, The support frame (7) has vertically extending grooves (73) on both sides. The slide block (71) is slidably installed in the groove (73). The upper end of the slide block (71) is connected to a lifting rod (72). The lifting rod (72) is connected to a drive device and is used to drive the upper hot press roller (61) to move up and down along the groove (73).

5. The thin film hot pressing composite device according to claim 1, characterized in that, The support frame (7) is externally connected to a transverse drive rod (8), which is connected to a transverse drive device and is used to drive the hot pressing mechanism (6) to slide along the axial direction and to adjust the relative transverse distance between the two sets of upper convex rings (611) and lower convex rings (621).

6. The thin film hot-pressing composite device according to claim 1, characterized in that, It also includes a filler conveying roller group (3), which is located between film conveying roller group one (1) and film conveying roller group two (2), and is used to convey filler (31) between film one (101) and film two (21).

7. A thin-film hot-pressing composite device according to claim 6, characterized in that, The filler (31) is a flocculent material with a strip-like structure. Each filler (31) is arranged in a parallel and uniform manner along the width direction and corresponds to the spacer groove (613) between the upper convex ring (611).

8. The thin film hot pressing composite device according to claim 1, characterized in that, The upper hot press roller (61) is provided with an upper pressing block (612) on its outer periphery; the lower hot press roller (62) is provided with a lower pressing block (622) on its outer periphery. During the rotation of the upper hot press roller (61) and the lower hot press roller (62), the upper pressing block (612) and the lower pressing block (622) can press against each other; the upper pressing block (612) is located between two upper convex rings (611), and the lower pressing block (622) is located between two lower convex rings (621).

9. A thin-film hot-pressing composite device according to claim 8, characterized in that, The upper pressing block (612) is provided with an upper pressing surface (6121), which is flush with the outermost contour surface of the upper convex ring (611). The lower pressing block (622) is provided with a lower pressing surface (6221) at its top, which is tangent to the inner surface of the outer edge of the lower convex ring (621). The upper pressing surface (6121) and the lower pressing surface (6221) can press against each other.

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