Folding carton and easy-to-tear carton

Abstract

The utility model relates to the technical field of packaging, and discloses a folding paper box and a paper box easy to tear, the folding paper box comprises a bottom plate, a first side plate, a second side plate, a third side plate and a fourth side plate are arranged around the bottom plate, bottom folding marks are respectively arranged between the bottom plate and the first side plate, between the bottom plate and the second side plate, between the bottom plate and the third side plate and between the bottom plate and the fourth side plate, and the bottom folding marks are arranged on the bottom plate. An accommodating space is formed by folding along the bottom crease; wherein the first side plate and the third side plate are oppositely arranged, and buckle holes are formed in the first side plate and the second side plate; the second side plate and the fourth side plate are oppositely arranged, buckling parts are arranged on the second side plate and the fourth side plate, and when the folding paper box is folded, the buckling parts are bent and inserted into the buckling holes; the paper box easy to tear comprises a box body and the folding paper box. The packaging box has the technical effects that the production cost is reduced, the recycling of packaging materials is realized, and the pollution to the environment is reduced.

Description

Technical Field

[0001] This utility model belongs to the field of packaging technology, specifically relating to a folding cardboard box and an easy-tear cardboard carton. Background Technology

[0002] Currently, electronic products typically use cardboard boxes as outer packaging, with the inside filled with expanded polyethylene (PE) or polystyrene (PS) foam. PE and PS foam offer high cushioning and shock resistance. The cardboard boxes are primarily made of corrugated cardboard, die-cut and creasing then folded. They can include slotted boxes, nesting boxes, and folding boxes. Wrapping the electronic product in the cardboard box provides excellent moisture and dust protection. Simultaneously, the PE or PS foam, encasing the electronic product and filling any remaining space inside the box, acts as a buffer during distribution and storage, reducing damage from collisions and compression during transport.

[0003] However, packaging made of expanded polyethylene and polystyrene foam has the problems of environmental pollution and overuse of limited resources. In addition, the high cost of polystyrene foam molds makes it difficult to use for packaging small quantities of products, which increases product costs. Packaging filled with expanded polyethylene or polystyrene foam in cartons has limitations in its use. Utility Model Content

[0004] To address the shortcomings of the existing technology, this utility model provides a folding cardboard box and an easy-tear carton. The folding cardboard box is formed by folding cardboard and is connected and fixed by inserting a buckle part into a buckle hole. It can replace packaging made of foamed polyethylene and polystyrene foam, which helps to reduce production costs and realize the recycling and reuse of packaging materials, thereby reducing environmental pollution.

[0005] The technical effects to be achieved by this utility model are realized through the following technical aspects:

[0006] In a first aspect, this utility model provides a folding cardboard box, including a base plate. The base plate is surrounded by a first side plate, a second side plate, a third side plate, and a fourth side plate. Bottom creases are provided between the base plate and the first side plate, the second side plate, the third side plate, and the base plate is folded along the bottom creases to form an accommodating space. The first side plate and the third side plate are arranged opposite to each other, and the first side plate and the second side plate are provided with snap-fit ​​holes. The second side plate and the fourth side plate are arranged opposite to each other, and the second side plate and the fourth side plate are provided with snap-fit ​​parts. When the cardboard box is folded, the snap-fit ​​parts are bent and inserted into the snap-fit ​​holes.

[0007] In some implementations, the second side panel includes an inner panel and an outer panel, the inner panel being connected to the bottom plate, and the buckle being disposed on the inner panel; a separation crease is provided between the inner panel and the outer panel, the inner panel and the outer panel are folded along the separation crease, and a separation area is formed between the inner panel and the outer panel, the separation area being separated from the accommodating space by the inner panel.

[0008] In some implementations, the second side plate further includes a wing plate with edge creases and connecting strips cut into it; both the inner plate and the outer plate have insertion holes, and after the wing plate is folded along the edge creases, the connecting strips are inserted into the corresponding insertion holes.

[0009] In some implementations, an edge banding strip is cut into the wing plate and inserted between the outer panel and the inner panel, wherein the edge banding strip, the inner panel, and the outer panel surround the partition area.

[0010] In some implementations, slots are provided on both the second side plate and the fourth side plate, and a partition for dividing the accommodating space is provided in the accommodating space, the partition being inserted into the slot.

[0011] In a first aspect, the present invention provides an easy-tear cardboard box, including a box body and the aforementioned folding cardboard box, wherein the folding cardboard box is disposed within the box body.

[0012] In some implementations, the housing includes a first outer flap and a second outer flap, the first outer flap covering the surface of the second outer flap and being bonded to the second outer flap, and the first outer flap being provided with an easy-tear strip.

[0013] In some implementations, one side of the folding carton is provided with a cushioning fold for filling the interior of the box.

[0014] In some implementations, the buffer fold card is provided with a buffer crease, the buffer fold card is folded along the buffer crease, and a sunken plate and a raised plate are formed.

[0015] In some implementations, the raised plate has a fixing hole, the lowered plate is cut to form a fixing strip, and a lifting hole is formed on the lowered plate at the cut of the fixing strip, and the fixing strip is inserted into the fixing hole.

[0016] In summary, this utility model has at least the following advantages:

[0017] 1. The folding cardboard box provided by this utility model has its first, second, third, and fourth side panels folded along the bottom crease. The bottom panel, first, second, third, and fourth side panels are folded into a cardboard box forming an accommodating space. After folding, the snap fasteners of the second and fourth side panels are inserted into their corresponding snap fastener holes. The first, second, third, and fourth side panels are connected through the snap fasteners and snap fastener holes, securing the folded cardboard box. Inserting the snap fasteners into the snap fastener holes improves the stability of the folding cardboard box. The folding cardboard box is made of folded cardboard. Compared with traditional foamed polyethylene and polystyrene packaging, it ensures lightweight packaging while saving packaging costs and is environmentally friendly.

[0018] 2. The easy-tear cardboard box provided by this utility model packages products by folding the cardboard box and the box body. The easy-tear cardboard box realizes paper material packaging, which can reduce packaging costs and can be recycled and reused to reduce the impact on the environment. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the unfolded form of a folding cardboard box according to a specific embodiment of the present utility model.

[0020] Figure 2 This is a schematic diagram of the overall structure of a folding paper box according to a specific embodiment of the present utility model.

[0021] Figure 3 This is a schematic diagram of the unfolded folding paper box according to Embodiment 2 of this utility model.

[0022] Figure 4 This is a schematic diagram showing the unfolded partition of a specific embodiment of the present utility model.

[0023] Figure 5 This is an exploded schematic diagram of an easy-tear cardboard box according to a specific embodiment of the present utility model.

[0024] Figure 6 This is a schematic diagram of the unfolded box body according to a specific embodiment of the present utility model.

[0025] Figure 7 This is a schematic diagram of the unfolded buffer card according to a specific embodiment of the present invention.

[0026] Marked in the image:

[0027] 1. Base plate; 11. Bottom crease; 12. Storage space;

[0028] 2. First side panel; 21. Buckle hole; 22. Transition section; 221. First crease; 23. Connecting section; 231. Second crease; 232. Third crease; 233. Folding angle;

[0029] 3. Second side panel; 31. Buckle part; 32. Fourth crease; 33. Inner panel; 331. Insertion hole; 34. Outer panel; 341. Outer crease; 35. Divider crease; 351. Divider area; 36. Wing panel; 361. Edge crease; 362. Connecting strip; 363. Edge sealing strip;

[0030] 4. Third side panel;

[0031] 5. Fourth side plate; 51. Slot;

[0032] 6. Partition plate; 61. Assembly slot; 62. Support hole;

[0033] 7. Folding cardboard box;

[0034] 8. Box body; 81. First outer flap; 811. Easy-tear strap; 82. Second outer flap; 83. Inner flap;

[0035] 9. Buffer fold; 91. Buffer crease; 92. Sinking plate; 921. Fixing strip; 922. Lifting hole; 93. Raising plate; 931. Fixing hole. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are some, but not all, of the embodiments of this utility model.

[0037] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0038] Example 1:

[0039] Please see the appendix Figure 1 and Figure 2 The folding cardboard box 7 of this utility model is folded from paper folding cards and can be used as inner packaging for electronic devices and accessories, playing a role in cushioning, support and separation, thereby effectively protecting the safety of the products. It has low usage cost and is environmentally friendly, which is in line with the concept of sustainable development.

[0040] The folding paper box 7 of this utility model includes a base plate 1. The base plate 1 is surrounded by a first side plate 2, a second side plate 3, a third side plate 4, and a fourth side plate 5. Bottom creases 11 are provided between the base plate 1 and the first side plate 2, the second side plate 3, the third side plate 4, and the fourth side plate 5. Specifically, the bottom creases 11 can be set along the perimeter of the base plate 1. The first side plate 2, the second side plate 3, the third side plate 4, and the fourth side plate 5 are folded along the bottom creases 11 to form an accommodating space 12. Specifically, the folding paper box 7 is folded into a rectangular box body.

[0041] The first side plate 2 and the third side plate 4 are arranged opposite to each other, and the first side plate 2 and the third side plate 4 are provided with snap-fit ​​holes 21. In some specific embodiments, the first side plate 2 and the third side plate 4 are located in the width direction of the base plate 1.

[0042] The second side plate 3 and the fourth side plate 5 are arranged opposite to each other. The second side plate 3 and the fourth side plate 5 are provided with a buckle part 31. When the cardboard box is folded, the buckle part 31 is bent and inserted into the buckle hole 21. In some specific embodiments, the second side plate 3 and the fourth side plate 5 are located in the length direction of the bottom plate 1.

[0043] In a preferred embodiment, the snap-fit ​​hole 21 can be a square hole, while the snap-fit ​​part 31 is a trapezoidal paper piece including a long side and a short side. When the snap-fit ​​part 31 is inserted into the snap-fit ​​hole 21, the long side of the snap-fit ​​part 31 is inserted into the corresponding snap-fit ​​hole 21, and the first side plate 2, the second side plate 3, the third side plate 4 and the fourth side plate 5 are connected and fixed, which can reduce the loosening of the folded paper box 7 during use. There is no need to use tape or glue for bonding and fixing, which is convenient to use and helps to save packaging costs.

[0044] In a preferred embodiment, both the first side panel 2 and the second side panel 3 include a transition section 22 and a connecting section 23. A bottom crease 11 is provided on the transition section 22. The first side panel 2 or the second side panel 3 is connected to the base plate 1 at the transition section 22. Specifically, a first crease 221 is provided on the transition section 22. The first crease 221 can be a rectangular fold line. Folding the transition section 22 along the first crease 221 forms a three-dimensional frame in the width direction of the folded cardboard box 7. Furthermore, different creases and cuts can be provided on the transition section 22 to form different through holes according to the actual product specifications, so that the transition section 22, after folding, adapts to the shape and specifications of the product.

[0045] The buckle hole 21 is provided on the connecting section 23. A second crease 231 is provided between the connecting section 23 and the transition section 22. The connecting section 23 is folded along the second crease 231 so that the buckle part 31 is inserted into the buckle hole 21. Two third creases 232 are provided on the connecting section 23. After the connecting section 23 is folded along the third crease 232, a folding angle 233 is formed on the connecting section 23. The folding angle 233 of the connecting section 23 can be folded towards the second side plate 3 and the fourth side plate 5 respectively. Then the buckle part 31 is inserted into the buckle hole 21, which can further enhance the stability of the connection.

[0046] In a preferred embodiment, both the second side plate 3 and the fourth side plate 5 are provided with a fourth fold line 32. The second side plate 3 and the fourth side plate 5 are folded along the fourth fold line 32. The fourth fold line 32 can be a rectangular fold line, which can form a three-dimensional frame in the length direction of the folded paper box 7.

[0047] When the folding cardboard box 7 is folded, the first side panel 2, the second side panel 3, the third side panel 4, and the fourth side panel 5 are folded sequentially along the bottom crease 11, forming an accommodating space 12 with the base plate 1. The transition section 22 is folded along the first crease 221, and the connecting section 23 is then folded sequentially along the second crease 231 and the third crease 232. Finally, the second side panel 3 and the fourth side panel 5 are folded along the fourth crease 32. The snap fastener 31 is inserted into the snap fastener hole 21, thus connecting and fixing the first side panel 2, the second side panel 3, the third side panel 4, and the fourth side panel 5. The folding cardboard box 7 is formed by folding with paper snap fasteners. The base plate 1, the first side panel 2, the third side panel 4, and the fourth side panel 5 can be die-cut using a die, which has a low die cost. Furthermore, the folding cardboard box 7 uses only cardboard, which is a renewable resource and can be recycled and reused. Cardboard replaces foamed polyethylene or polystyrene foam packaging, offering cost reduction and environmental benefits. It is also suitable for packaging small quantities of products, addressing the limitations of traditional packaging.

[0048] Example 2:

[0049] The difference between this embodiment and Embodiment 1 is that this embodiment further optimizes the structure of the second side plate 3 of this utility model. Please refer to [link / reference]. Figures 2-4 .

[0050] Please see Figure 2 and Figure 3In this embodiment, the second side panel 3 includes an inner panel 33 and an outer panel 34. The inner panel 33 is connected to the bottom panel 1. A fourth fold 32 is provided on the inner panel 33, and a snap-fit ​​part 31 is provided on the inner panel 33. A separating fold 35 is provided between the inner panel 33 and the outer panel 34. Specifically, the separating fold 35 can be a rectangular fold line. The inner panel 33 and the outer panel 34 are folded along the separating fold 35, and a separating area 351 is formed between the inner panel 33 and the outer panel 34. The separating area 351 is separated from the accommodating space 12 by the inner panel 33. The folded cardboard box 7 forms the accommodating space 12 and the separating area 351, which can be used to package different products, components, or accessories. The product packaging is reasonable and can play a certain role in cushioning and positioning.

[0051] In some specific embodiments, the outer plate 34 is provided with an outer fold 341, the inner plate 33 is folded along the dividing fold 35, the inner plate 33 and the outer plate 34 are folded along the dividing fold 35, and the outer plate 34 is folded along the outer fold 341, so that the cross-section of the second side plate 3 is a zigzag wave shape, forming a three-dimensional buffer structure.

[0052] In some preferred embodiments, the second side panel 3 further includes a wing panel 36, which has an edge crease 361 and a connecting strip 362 cut into it. Both the inner panel 33 and the outer panel 34 have insertion holes 331. Specifically, the insertion holes 331 can be elongated through holes and multiple holes are provided. After the wing panel 36 is folded along the edge crease 361, the connecting strips 362 are inserted into the corresponding insertion holes 331, thus connecting and fixing the wing panel 36 and the second side panel 3, which helps to further improve the overall structural strength of the folding cardboard box 7.

[0053] In a specific embodiment, an edge sealing strip 363 is cut and formed on the wing plate 36. The edge sealing strip 363 is located between two connecting strips 362. The connecting strips 362 and the edge sealing strip 363 make the wing plate 36 form a comb-shaped end. When the connecting strip 362 is inserted into the insertion hole 331, the edge sealing strip 363 is inserted between the outer plate 34 and the inner plate 33. The edge sealing strip 363, the inner plate 33, and the outer plate 34 surround the partition area 351.

[0054] Please see Figure 2 and Figure 4In a preferred embodiment, both the second side plate 3 and the fourth side plate 5 have slots 51. Specifically, the slot 51 of the second side plate 3 is located on the inner plate 33, and a partition 6 for dividing the accommodating space 12 is provided within the accommodating space 12. The partition 6 is inserted into the slot 51. Specifically, the partition 6 can be formed by folding a rectangular cardboard in half. The partition 6 has an assembly groove 61. When the partition 6 is inserted into the slot 51, the partition 6 forms a tenon-and-mortise structure with the second side plate 3 and the fourth side plate 5 respectively at the assembly groove 61 to achieve connection. The partition 6 can have support holes 62. When the partition 6 is folded in half, the support holes 62 form a semi-circular slot, which can fix product accessories or components.

[0055] The folding cardboard box 7 forms an inner panel 33, an outer panel 34, and a wing panel 36 via the second side panel 3, which can form partition areas 351 at intervals. While supporting product accessories or components, it also separates different accessories or components, making the product more stable during transportation and reducing product damage caused by shaking and collisions. The folding cardboard box 7 does not require adhesive tape or glue; it achieves connection through different folding structures, which improves the ease of assembly.

[0056] Example 3:

[0057] This embodiment, based on the above embodiments, provides an easy-tear cardboard box. Please refer to [link / reference]. Figures 5-7 .

[0058] Please see Figure 5 and Figure 6 An easy-tear cardboard box includes a box body 8 and a folding cardboard box 7, with the folding cardboard box 7 disposed inside the box body 8. In a preferred embodiment, the box body 8 includes a first outer flap 81 and a second outer flap 82. The first outer flap 81 covers the surface of the second outer flap 82 and is bonded to the second outer flap 82. Specifically, adhesive tape is pasted on the inner surface of the first outer flap 81, and the first outer flap 81 is bonded to the second outer flap 82 by the adhesive tape. An easy-tear strip 811 is provided on the first outer flap 81, allowing the box body 8 to be opened easily and quickly without the need for additional opening tools such as scissors, making operation convenient and saving packaging materials. Simultaneously, when workers package product accessories or components, they can simply place the folding cardboard box 7 inside the box body 8, and then bond the first outer flap 81 and the second outer flap 82 together to complete the packaging, which helps reduce the labor intensity of workers and improves packaging efficiency.

[0059] Specifically, the box body 8 includes an inner flap 83. When the box body 8 is packaged, the inner flap 83 is located below the second flap to achieve the sealing of the box body 8.

[0060] Please see Figure 5 and Figure 7In a preferred embodiment, a buffer folding card 9 for filling the interior of the box body 8 is provided on one side of the folding cardboard box 7. Specifically, the number of buffer folding cards 9 can be set according to the specifications of the box body 8 and the folding cardboard box 7, so as to reduce the occurrence of product accessories or devices falling out of the folding cardboard box 7 during transportation when the folding cardboard box 7 and the box body 8 are not compatible.

[0061] In some specific embodiments, the buffer fold card 9 is provided with a buffer crease 91. The buffer fold card 9 is folded along the buffer crease 91 to form a sunken plate 92 and a raised plate 93. Specifically, when the buffer fold card 9 is placed between the inner flap 83 of the box body 8 and the folded cardboard box 7, the raised plate 93 contacts the inner flap 83, and the sunken plate 92 contacts the folded cardboard box 7. Further, the raised plate 93 is provided with a fixing hole 931, and the sunken plate 92 is cut to form a fixing strip 921. A lifting hole 922 is formed on the sunken plate 92 at the cut of the fixing strip 921. The buffer fold card 9 can be easily pulled out from the box body 8 through the lifting hole 922, which is convenient to operate. The fixing strip 921 is inserted into the fixing hole 931. By inserting the fixing strip 921 into the fixing hole 931, the edge strength of the buffer fold card 9 at the lifting hole 922 can be enhanced. Specifically, the fixing strip 921 includes an anti-detachment end. When the fixing strip 921 is inserted into the fixing hole 931, the anti-detachment end can reduce the possibility of the fixing strip 921 coming out of the fixing hole 931.

[0062] The easy-tear cardboard box of this utility model can provide cushioning and protection for the product through the folding cardboard box 7 and the cushioning card 9.

[0063] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0064] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this utility model is in use. They are only for the convenience of describing this utility model 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. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0065] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," not that the structure must be completely horizontal, but can be slightly tilted.

[0066] In this invention, unless otherwise expressly specified and limited, "above or below" the first feature may include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on" the first feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the first feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0067] Although the description of this utility model has been given in conjunction with the specific embodiments described above, it is obvious to those skilled in the art that many substitutions, modifications, and variations can be made based on the above description. Therefore, all such substitutions, modifications, and variations are included within the spirit and scope of the appended claims.

Claims

1. A folded carton, characterized in that, Includes a base plate (1), and the base plate (1) is surrounded by a first side plate (2), a second side plate (3), a third side plate (4) and a fourth side plate (5). The base plate (1) is provided with bottom creases (11) between itself and the first side plate (2), the second side plate (3), the third side plate (4) and the fourth side plate (5), and is folded along the bottom creases (11) to form an accommodating space (12). The first side plate (2) and the third side plate (4) are arranged opposite to each other, and the first side plate (2) and the second side plate (3) are provided with buckle holes (21); The second side plate (3) and the fourth side plate (5) are arranged opposite to each other. The second side plate (3) and the fourth side plate (5) are provided with buckle parts (31). When the folding paper box is folded, the buckle parts (31) are bent and inserted into the buckle hole (21).

2. The folded carton of claim 1, wherein, The second side panel (3) includes an inner panel (33) and an outer panel (34). The inner panel (33) is connected to the bottom plate (1), and the buckle (31) is provided on the inner panel (33). A separating crease (35) is provided between the inner plate (33) and the outer plate (34). The inner plate (33) and the outer plate (34) are folded along the separating crease (35) and folded together to form a separating area (351) between the inner plate (33) and the outer plate (34). The separating area (351) is separated from the accommodating space (12) by the inner plate (33).

3. The folded carton of claim 2, wherein, The second side plate (3) also includes a wing plate (36), on which edge creases (361) are provided, and connecting strips (362) are cut on the wing plate (36); Both the inner plate (33) and the outer plate (34) are provided with insertion holes (331). After the wing plate (36) is folded along the edge crease (361), the connecting strip (362) is inserted into the corresponding insertion hole (331).

4. The folded carton of claim 3, wherein, An edge sealing strip (363) is cut on the wing plate (36) and inserted between the outer plate (34) and the inner plate (33). The edge sealing strip (363), the inner plate (33), and the outer plate (34) surround the partition area (351).

5. The folded carton of claim 1, wherein, The second side plate (3) and the fourth side plate (5) are provided with slots (51), and the accommodating space (12) is provided with a partition (6) for dividing the accommodating space (12), and the partition (6) is inserted into the slot (51).

6. A carton of the type which is readily torn, characterised in that, It includes a box body (8) and a folding cardboard box (7) according to any one of claims 1 to 5, wherein the folding cardboard box (7) is disposed inside the box body (8).

7. The easy-open carton of claim 6, wherein, The housing (8) includes a first outer cover (81) and a second outer cover (82). The first outer cover (81) covers the surface of the second outer cover (82) and is bonded to the second outer cover (82). The first outer cover (81) is provided with an easy-tear strip (811).

8. The easy-open carton of claim 7, wherein, One side of the folding cardboard box (7) is provided with a cushioning fold card (9) for filling the interior of the box body (8).

9. The easy-open carton of claim 8, wherein, The buffer fold (9) is provided with a buffer crease (91), the buffer fold (9) is folded along the buffer crease (91) to form a sunken plate (92) and a raised plate (93).

10. The easy-open carton of claim 9, wherein, The raised plate (93) has a fixing hole (931), the lowered plate (92) is cut to form a fixing strip (921), and a lifting hole (922) is formed on the lowered plate (92) at the cut of the fixing strip (921). The fixing strip (921) is inserted into the fixing hole (931).

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