Anti-bulging blank sheets and packaging boxes

Abstract

To prevent bulging of a body in a wrap-around type packaging box.SOLUTION: A blank sheet of a wrap-around packaging box includes a main body, an outer flap 6, and an inner flap 7. The main body has an arrangement in which a rectangular side surface plate 4 is sandwiched between a rectangular top surface plate and a rectangular bottom surface plate 5, and the outer flap extends from the short side of the top surface plate and the short side of the bottom surface plate, and the inner flap extends from the short side of the side surface plate. A groove is formed between the outer flap and the inner flap adjacent to each other, and a width of the groove at a position where a folding line of the outer flap is located is narrower than twice the plate thickness of the blank sheet. A folding line between the top surface plate and the side surface plate and a folding line 8b between the bottom surface plate and the side surface plate are provided closer to the side of the side surface plate than the center of the groove.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a wrap-around blank sheet made of thick paper such as corrugated cardboard or paperboard for wrapping and packaging an article, and to a packaging box assembled from said blank sheets. [Background technology]

[0002] A wraparound type packaging box as shown in FIG. 2 of Patent Document 1 has been known for packaging items such as tissue paper, instant noodles, and retort foods. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-298018 A Summary of the Invention [Problem to be solved by the invention]

[0004] When multiple packaging boxes containing items are stacked, the side panels of the lower packaging boxes are crushed by the weight, which causes a problem of so-called body bulging. In particular, when multiple packaging boxes are stacked and stored under hot and humid summer conditions, the long sides of the packaging boxes can become deformed by body bulging, resulting in defective products. The body bulging can also have a detrimental effect on the packaged items, such as deformation. An object of the present invention is to prevent bulging of the body of a wraparound type packaging box. [Means for solving the problem]

[0005] The present invention provides a blank sheet for a wraparound type packaging box having a main body, outer flaps, and inner flaps, the main body being arranged such that a rectangular side panel is sandwiched between a rectangular top panel and a rectangular bottom panel, the outer flaps extend from the short sides of the top panel and the short sides of the bottom panel, the inner flaps extend from the short sides of the side panels, a groove is formed between adjacent outer flaps, the width of the groove at a fold line of the outer flap is narrower than twice the thickness of the blank sheet, and the fold line between the top panel and the side panels is narrower than twice the thickness of the blank sheet. End of or A fold line between the bottom panel and the side panel End of is the distance from the center of the groove Inner flap Come closer The groove is connected to the end of the fold line between the top panel and the side panel or the end of the fold line between the bottom panel and the side panel. , The ends of the fold lines between the side panels and the inner flaps are spaced apart from each other at intervals narrower than the panel thickness. The above-mentioned problem was solved by providing a blank sheet for a wrap-around type packaging box, characterized in that: Effect of the Invention

[0006] It was possible to prevent the body of a wrap-around type packaging box from swelling. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a plan view of a blank sheet according to the prior art; [Diagram 2] FIG. [Diagram 3] 3(a) is an explanatory diagram of a groove, (b) is an enlarged view of the circle A in FIG. 2 according to the embodiment, (c) is an enlarged view of a conventional groove, and (d) is an enlarged view of the groove. [Figure 4] 1A is a perspective view of a packaging box assembled from the blank sheet of the embodiment; and FIG. 1B is a perspective view of a packaging box assembled from the blank sheet of the prior art. [Diagram 5] An explanatory diagram of buckling. (a) A perspective view of multiple packaging boxes stacked up. (b) An enlarged view of the area around the bottom packaging box. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] (Example)

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the same reference numerals in different drawings indicate parts having the same function, and duplicated descriptions in each drawing will be omitted as appropriate. In addition, although there are no inherent directions such as left / right or front / back on the blank sheet 1B or the packaging box 1, directions may be illustrated in the drawings for explanation purposes. The directions are limited to the drawings and represent the left, right, front, and back directions for the sake of explanation.

[0010] [Common features between the prior art and the embodiment] (Main body area) 1 is a plan view of a conventional blank sheet 1B. The main body 2 refers to a portion in which a top panel 3, a side panel 4, a bottom panel 5, and a side panel 4 are arranged in this order. The top panel 3, the side panel 4, and the bottom panel 5 are all rectangular, and the main body 2 is arranged such that the long sides of each panel are connected to each other, with the rectangular side panel 4 being sandwiched between the rectangular top panel 3 and the rectangular bottom panel 5. The top panel 3 is disposed at the front end of the blank sheet 1B in the figure. The top panel 3 has front and rear long sides, of which the rear long side forms a fold line (between the top panel and the side panel) 8a, and the front long side forms a fold line (between the top panel and the seam) 8e. The left and right short sides are provided with fold lines (between the top panel and the outer flap) 8d1. The area that will become the top panel 3 is formed on the blank sheet 1B by these fold lines. The bottom plate 5 has fold lines (between the bottom plate and the side plates) 8b on the front and back long sides and fold lines (between the bottom plate and the outer flaps) 8d2 on the left and right short sides, so that the area that will become the bottom plate 5 is formed on the blank sheet 1B. One of the two side panels 4 is sandwiched between the top panel 3 and the bottom panel 5. This side panel 4 has a fold line (between the top panel and the side panel) 8a on the top panel 3 side, a fold line (between the bottom panel and the side panel) 8b on the bottom panel 5 side, and fold lines (between the side panel and the inner flap) 8c on the left and right short sides, thereby forming an area that will become the side panel 4 on the blank sheet 1B. The other of the two side panels 4 has a fold line (between the bottom panel and the side panel) 8b on the long side facing the bottom panel 5, and the other is the rear end of the blank sheet 1B. In addition, fold lines (between the side panel and the inner flap) 8c are provided on the left and right short sides, so that the area that will become the side panel 4 is formed on the blank sheet 1B. The fold line (between the bottom panel and the side panel) 8b, the fold line (between the top panel and the side panel) 8a, and the fold line (between the top panel and the joint) 8e are arranged parallel to each other, and are configured to form a rectangular parallelepiped when assembled.

[0011] (Outer flap / inner flap) The outer flaps 6 extend from the left and right short sides of the top panel 3 and the left and right short sides of the bottom panel 5 in the figure, and a total of four outer flaps 6 are provided on the blank sheet 1B. Each outer flap 6 has a rectangular shape having a pair of outer flap sides 61 . The inner flaps 7 extend from the right and left short sides of the two side panels 4, and a total of four inner flaps 7 are provided on the blank sheet 1B. Each inner flap 7 has a rectangular shape having a pair of inner flap sides 71 .

[0012] (groove) A groove 9 is formed between the adjacent outer and inner flaps 6, 7.

[0013] (Successor) In both the embodiment and the prior art, the seam 32 is provided at the front end of the blank sheet 1B (the front end in Figs. 1 and 2), and extends from the fold line (between the top panel and the seam) 8e.

[0014] (adhesion) At the width surface 12 of the packaging box 1, the outer flap 6 is wrapped around the folded inner flap 7 and fixed with an adhesive. The seam 32 is adhered to the long surface 11 (side panel 4) and closed to form the packaging box 1.

[0015] [Features of the embodiment] Fig. 2 is a plan view of a blank sheet 1B of the embodiment. Fig. 3(a) is an enlarged view of the circle A in Fig. 2 according to the embodiment. Fig. 3(b) is an enlarged view of Fig. 3(a). The same points as the conventional technology will be omitted, and the description will focus on the features of the embodiment.

[0016] (Fold line structure) In the embodiment, the fold line (between the top panel and the side panel) 8a and the fold line (between the bottom panel and the side panel) 8b have the same structure. In Fig. 2, only the fold line (between the top panel and the side panel) 8a is labeled for the sake of explanation, but the fold line (between the bottom panel and the side panel) 8b also has the same structure. The fold line (between the top panel and the side panel) 8a has a branch point 8g, at which the fold line that was previously a single line branches. The fold line that branches at the branch point 8g splits into two parallel fold lines, one on the top panel 3 side and the other on the side panel 4 side, and then returns to a single fold line. In the embodiment, the fold line (between the top panel and the side panel) 8a has four branch points 8g, from the left, so that it becomes a single fold line region 8h, a double fold line region 8f, a single fold line region 8h, a double fold line region 8f, and finally a single fold line region 8h. The number of double fold line regions 8f and the ratio of their length to the single fold line regions 8h will vary depending on the thickness and strength of the blank sheet 1B, as well as the size and contents of the packaging box 1, and so the embodiment is merely one example of the present invention.

[0017] 2, the rear end of the main body 2 is interrupted by the side panel 4. Therefore, it is not possible to provide a double fold line region 8f at this location, but a recessed fold line 8j passing through the side panel 4 may be provided at the same position as the double fold line region 8f provided at the fold line (between the top panel and the side panel) 8a.

[0018] (groove shape) In the prior art, as shown in FIG. 1, an outer flap side 61 forming one side of the groove 9 and an inner flap side 71 forming the other side of the groove 9 are parallel to each other, forming a deep U-shaped groove 9. In contrast, as shown in Figures 3(a) and 3(b), in the embodiment, a groove 9 is provided between adjacent outer and inner flaps 6 and 7, which is the same as the prior art, but the side edge 61 of the outer flap is inclined so as to widen from the back of the groove 9 toward the opening. On the other hand, the inner flap side edge 71 extending from the short side of the side panel 4 extends parallel to the long side of the side panel 4, that is, the fold line (between the bottom panel and the side panel) 8b and the fold line (between the top panel and the side panel) 8a.

[0019] The groove 9 is for making it easier to assemble the packaging box 1. During assembly, the inner flap 7 is folded, and then the outer flap 6 is folded so as to cover the outside of the inner flap 7, so there is a slight misalignment width s between the fold line (between the side panel and the inner flap) 8c and the fold line (between the bottom panel and the outer flap) 8d2. This slight misalignment width s is set to approximately the plate thickness h because the outer flap 6 covers the outside of the inner flap 7 when the packaging box 1 is assembled. In the embodiment, it is slightly shorter than the plate thickness h of 2.5 mm. As described above, the inner flap side 71 extending from the short side of the side panel 4 extends parallel to the long side of the side panel 4, i.e., the fold line (between the bottom panel and the side panel) 8b and the fold line (between the top panel and the side panel) 8a. The inner flap side 71 is wavy.

[0020] (The fold line (between the top panel and the side panel) and the position of the fold line (between the top panel and the side panel)) 3(c) is an enlarged view of the groove 9 of the prior art. In the prior art, a fold line (between the bottom panel and the side panel) 8b extends from the center of the groove 9. Although not shown, the fold line (between the top panel and the side panel) 8a is also the same, and also extends from the center of the groove 9. In Fig. 3(b), which is an enlarged view of the groove 9 of the embodiment, the fold line (between the bottom panel and the side panel) 8b between the bottom panel 5 and the side panel 4 is provided closer to the side panel 4 than the center of the groove 9. The same is true for the fold line (between the top panel and the side panel) 8a, although not shown.

[0021] (groove width) In the embodiment, the width of the groove 9 at the fold line of the outer flap 6 is narrower than twice the thickness of the blank sheet 1B. As shown in Fig. 3(b), the narrowest width of the groove 9 is 3.5 mm, which is narrower than twice the thickness h of the blank sheet 1B. In contrast, in the conventional groove 9 shown in FIG. 3(c), the groove 9 is formed to have a width of 5 mm, which is exactly twice the plate thickness h of the blank sheet 1B, ie, 2.5 mm.

[0022] The above points are different from the prior art in the embodiment, which gives rise to the following features in the embodiment. (Feature 1) The following effects are produced by (the width of the groove) and (the fold line (between the top panel and the side panel) and the position of the fold line (between the top panel and the side panel)). FIG. 4 is a perspective view of a packaging box 1 assembled from a blank sheet 1B of the embodiment. The packaging box 1 has a rectangular parallelepiped shape, and the corners of the packaging box 1 are formed by folding the crease line (between the side panel and the inner flap) 8c and the crease line (between the bottom panel and the side panel) 8b. As shown in FIG. 3(b), the width of the groove 9 at the position of the crease line of the outer flap 6, that is, the width of the groove 9 at the position where the crease line (between the bottom panel and the side panel) 8b and the groove 9 meet, is 3.5 mm, which is narrower than twice the plate thickness of the blank sheet 1B. In addition, the crease line (between the side panel and the inner flap) 8c and the crease line (between the bottom panel and the side panel) 8b are provided closer to the side panel 4 than the center of the groove 9. As shown in FIG. 3(b), if this shift width is w, in this embodiment, the shift width w is 1 mm.

[0023] The positional relationship between the fold line (between the side panel and the inner flap) 8c and the fold line (between the bottom panel and the side panel) 8b in the embodiment is much closer than in the conventional technology. The inner flap 7 and the side panel 4, which are 2.5 mm thick, are folded to fit within a width w of 1 mm when formed. Therefore, when the packaging boxes 1 are stacked and a load (compressive force) is applied to the top side 3, corners with high strength are created. This improvement in strength occurs at all corners of the packaging box 1.

[0024] The corner of B enclosed in a frame in Fig. 4(a) corresponds to the area in the enlarged view in Fig. 3(b). Focusing on the corners of B and A in Fig. 4(a), it can be seen that when multiple packaging boxes 1 are stacked, a load is applied from the compressed corner of A through the fold line (between the side panel and the inner flap) 8c to the compressed corner of B. It can be seen that the steps of the inner flap 7 are vertical, and the ridge line 13 formed by the fold line (between the side panel and the inner flap) 8c acts as a support pillar to provide support. The entire folded inner flap 7 also rests on the bottom panel 5 and is sandwiched between the bottom panel 5 and the top panel 3, thereby contributing to bearing the load. On the other hand, in the conventional technology shown in Fig. 3(c), the corners do not get compressed as in the embodiment, but rather the bottom panel 5 and the inner flap 7 get slightly separated at the corners. The inner flap 7 does not contribute to supporting the load, and when the load is applied to the long surface 11, the trunk bulges.

[0025] (Feature 2) (Fold line structure) In the embodiment of Fig. 2, a double crease line region 8f and a single crease line region 8h are provided on the crease line (between the top panel and the side panel) 8a and the crease line (between the bottom panel and the side panel) 8b of the blank sheet 1B. The double crease line region 8f is slightly recessed when the packaging box 1 is assembled as shown in Fig. 4(a). FIG. 5 is an explanatory diagram of buckling, in which FIG. 5(a) is a perspective view of a state in which multiple packaging boxes 1 are stacked, and FIG. 5(b) is an enlarged view of the periphery of the bottommost packaging box 1. The bottommost packaging box 1 and the vicinity of the long surface 11 of the packaging box 1 placed on the bottommost packaging box 1 are shown. In the single fold line region 8h of the bottommost packaging box 1, the ridge line 13 formed by folding the fold line (between the bottom panel and the side panel) 8b buckles to form the buckling region 8i. This buckling progresses as follows. The load acting on the long surface 11 (side panel 4) is concentrated on the multiple single fold line regions 8h because the double fold line region 8f is recessed. The single fold line region 8h that can no longer withstand the load buckles starting from the branch point 8g, and the buckling region 8i expands. In this way, when a large load is applied, the double fold line region 8f functions as a buckling induction line.

[0026] As a result, a very noticeable bulge is replaced by buckling of the less noticeable ridge 13 (single fold line region 8h). The ridge 13 formed by folding the fold line (between the side panel and the inner flap) 8c is strong as described above and continues to support the load. The single fold line region 8h buckles in the left and right central parts of the long face 11 (side panel 4), causing the original height H of the packaging box 1 to decrease slightly. In contrast, the ridges 13 formed by folding the fold lines (between the side panel and the inner flap) 8c on both the left and right sides are strong and maintain the height H even when a load is applied.

[0027] In addition, as described above, the inner flap 7 between the top panel 3 and the bottom panel 5 is firmly folded at the corners B and A, so that the load can be supported only by the corners and the ridges 13. When buckling occurs on the long surface 11 (side panel 4), the height H of the packaging box 1 can no longer be maintained on the long surface 11 (side panel 4) side, so the load gradually shifts to the width surfaces 12 on both sides as the buckling progresses. Since the inner flap 7 is present on the width surfaces 12, the inner flap 7, which initially did not contribute to support because the inner flap side edge 71 only lightly contacts between the top panel 3 and the bottom panel 5, gradually begins to support the load due to the influence of the buckling deformation occurring on the long surface 11 (side panel 4). Conversely, the long surface 11 (side panel 4) side no longer bears the load, so the body is prevented from bulging.

[0028] (Feature 3) Since the inner flap 7 has an inner flap side 71 extending from the short side of the side panel 4 and extending parallel to the long side of the side panel 4, the inner flap side 71 can contact both the top panel 3 and the bottom panel 5, and the inner flap 7 itself functions as a support member. The packaging box 1 is supported by a pair of width faces 12, and the load on the long face 11 is reduced, preventing the box from bulging. Comparing the embodiment shown in Figure 3(b) with the prior art shown in Figure 3(c), in both cases the inner flap 7 has an inner flap side edge 71 extending from the short side of the side panel 4 parallel to the long side of the side panel 4. However, the embodiment has (Feature 1), and the combination of (Feature 1) and (Feature 3) brings about an advantageous effect. As described above, in the conventional technology of Fig. 3(c), the corners are not compressed as in the embodiment, and instead the bottom panel 5 and the inner flap 7 are slightly separated at the corners. The same is true for the top panel 3 and the inner flap 7, and the inner flap 7 does not play a significant role in supporting the load. In the embodiment, the positional relationship between the fold line (between the side panel and the inner flap) 8c and the fold line (between the bottom panel and the side panel) 8b is much closer than in the conventional technology, and as shown in FIG. 3(b), in the embodiment, the shift width w is 1 mm. Therefore, when the packaging box 1 is assembled, the inner flap 7 is separated from the top panel 3 and the bottom panel 5 in the conventional technology, whereas in the embodiment, it is sandwiched between the top panel 3 and the bottom panel 5. In (characteristic point 3), the inner flap side edge 71 of the inner flap 7 extending from the short side of the side panel 4 extends parallel to the long side of the side panel 4. The inner flap side edge 71 contacts the top panel 3 and the bottom panel 5 over its entire length. Thus, in the embodiment, the proportion of the load received by the inner flap 7 is much greater than in the conventional technology.

[0029] (Feature 4) In the embodiment, as shown in Fig. 3(b), the inner flap side 71 extending from the short side of the side panel 4 is formed in a wavy shape. As described above, this inner flap side 71 is the side that abuts against the top panel 3 or the bottom panel 5 when assembled. Since the inner flap side 71 is formed in a wavy shape, the waves are crushed when a load is applied. This increases the contact area of ​​the inner flap side 71 that is in close contact with the top panel 3 or the bottom panel 5 and receives the load, allowing the load to be received evenly. This prevents the body from becoming bulging due to uneven load support.

[0030] As described above, the embodiment has a number of features for preventing bulging. These features may be used alone, but by combining them, the effect can be enhanced. Moreover, the blank sheet 1B of the embodiment can be assembled to provide a wrap-around type packaging box 1 filled with contents.

[0031] (test) In both the embodiment and the conventional technique (comparative example), a blank sheet 1B having the same strength and a thickness h of 2.5 mm was used. A packaging box 1 was assembled using the blank sheet 1B of the conventional technique shown in FIG. 1 and the blank sheet 1B of the embodiment shown in FIG. In the prior art (comparison example), as shown in Figure 3(c), in blank sheet 1B, the width of groove 9 at the position of the fold line of outer flap 6 is 5 mm, which is twice the thickness of the blank sheet, and fold line (between the top panel and side panel) 8a and fold line (between the bottom panel and side panel) 8b are provided so as to pass through the center of groove 9. In the embodiment, as shown in Fig. 3(b), the width of the groove 9 at the fold line of the outer flap 6 is 3.5 mm, which is narrower than twice the thickness of the blank sheet. The fold line (between the top panel and the side panel) 8a and the fold line (between the bottom panel and the side panel) 8b are provided closer to the side panel 4 than the center of the groove 9, and are provided at a position that divides the width of the groove 9, 3.5 mm, into 2.5 mm and 1 mm. The packaging box was left for three days under conditions of a temperature of 30° C., a humidity of 70% RH, and a load of 48 kg, and the amount of bulging of the long side 11 and the wide side 12 of the packaging box 1 was measured.

[0032] [Table 1]

[0033] As a result, in the embodiment, the bulge of the long face 11 was suppressed to 1 mm, whereas in the conventional technology (comparative example), the bulge was as much as 11 mm. In the embodiment, the load is concentrated on the inner flap 7 of the width surface 12, but the bulge of the width surface 12 of the packaging box 1 is suppressed to 2 mm. In contrast, the bulge of the width surface 12 of the packaging box 1 of the conventional technology (comparative example) is 4 mm. As a result of the above tests, it was confirmed that the embodiment can effectively prevent body bulge and solve the problem.

[0034] The above describes the embodiments of the present invention in detail with reference to the drawings, and explains aspects including various characteristic points. However, the specific configuration is not limited to these embodiments, and the present invention also includes design changes and the like that do not deviate from the gist of the present invention.

[0035] Furthermore, the above-described embodiments and various aspects can be combined by utilizing each other's technologies, so long as there is no particular contradiction or problem in the purpose, configuration, or the like. [Explanation of symbols]

[0036] 1 packaging box 1B Blank Sheet 11 long side 12 Width side 13 Ridgeline 2 Main unit 3 Top plate 32 Successor 4 Side plate 5 Bottom plate 6 Outer flap 61 Outer flap side 7 Inner flap 71 Inner flap side 8a Fold line (between top panel and side panel) 8b Fold line (between bottom panel and side panel) 8c Fold line (between side panel and inner flap) 8d1 Fold line (between top panel and outer flap) 8d2 Fold line (between bottom panel and outer flap) 8e Fold line (between top panel and joint) 8f Double fold line area 8g Branching point 8h Single fold line area 8i buckling area 8j recessed crease line 9 grooves h Plate thickness H Height of the packaging box w Width s Displacement

Claims

1. A blank sheet for a wrap-around type packaging box having a main body, an outer flap, and an inner flap, The main body is arranged such that a rectangular side panel is sandwiched between a rectangular top panel and a rectangular bottom panel, The outer flaps extend from the short sides of the top panel and the short sides of the bottom panel, The inner flap extends from a short side of the side panel, A groove is formed between the adjacent outer flap and the adjacent inner flap, and the width of the groove at the position of the fold line of the outer flap is narrower than twice the plate thickness of the blank sheet, An end of the fold line between the top panel and the side panel or an end of the fold line between the bottom panel and the side panel is connected to the groove closer to the inner flap side than the center of the groove, A blank sheet for a wraparound type packaging box, characterized in that the end of the fold line between the top panel and the side panel or the end of the fold line between the bottom panel and the side panel is spaced apart from the end of the fold line between the side panel and the inner flap by a distance narrower than the plate thickness.

2. 2. The blank sheet for a wraparound packaging box according to claim 1, wherein at least one of the fold lines between the top panel and the side panel and the fold line between the bottom panel and the side panel has at least one region where the fold line branches off and then returns to one.

3. A blank sheet for a wraparound type packaging box according to claim 1 or 2, characterized in that the inner flap has an inner flap side edge extending from the short side of the side panel and extending parallel to the long side of the side panel.

4. A blank sheet for a wraparound type packaging box according to any one of claims 1 to 3, characterized in that the inner flap has a wavy side edge extending from the short side of the side panel.

5. The wrap-around type packaging box according to any one of claims 1 to 4, wherein the blank sheets are assembled and contents are placed inside the box.

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