Packing box

Abstract

The rigidity of the hand holes is ensured by folding back the folded-over pieces of the outer and inner flaps. [Solution] The packaging box has an outer flap (15a) that is attached to a pair of inner flaps (14a, 14b). The packaging box is provided with a first hand-hole shaped fold-over piece (21) formed on the outer flap and a pair of second fold-over pieces (25a, 25b) formed on the pair of inner flaps. The pair of second fold-over pieces have one side edge (26a, 26b) of the pair of inner flaps, and the fold lines (L10, L11) of the pair of second fold-over pieces are positioned along the fold line (L9) of the first fold-over piece. The pair of inner flaps are opened so that when the pair of second fold-over pieces are pressed into the first fold-over piece, the pair of second fold-over pieces fold back in the direction of the fold of the first fold-over piece.

Description

Technical Field

[0001] The present invention relates to a packaging box.

Background Art

[0002] Conventionally, a packaging box called a wraparound case that wraps a product is known (see, for example, Patent Document 1). Such a packaging box has a cylindrical body portion formed of a bottom wall, an upper wall, and a pair of side walls, and is assembled by adhering a pair of outer flaps connected to the bottom wall and the upper wall to a pair of inner flaps connected to each side wall from the outside. Further, folding pieces are formed on the upper outer flap and each inner flap by fold lines and cut lines. By folding the folding pieces of the upper outer flap and each inner flap inward along the fold lines, hand holes for gripping the packaging box are formed on each side surface of the packaging box.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the packaging box described in Patent Document 1, the outer flap is adhered to a pair of inner flaps, and folding pieces are formed on the pair of inner flaps so as to overlap the folding piece of the upper outer flap. However, depending on the adhesion position of the upper outer flap and the pair of inner flaps, even if the folding piece of the outer flap is pushed in, the folding pieces of the pair of inner flaps cannot be rolled up. Further, the same problem may occur even when a pair of inner flaps are not adhered to the outer flap in another type of cardboard box such as an A-type cardboard box.

[0005] Therefore, an object of the present invention is to provide a packaging box capable of ensuring the rigidity of hand holes by folding the folding pieces of the outer flap and the inner flap. [Means for solving the problem]

[0006] A packaging box according to one aspect of the present invention is a packaging box in which a pair of inner flaps are folded inside an outer flap, comprising: a first hand-hole shaped fold-off piece formed on the outer flap; and a second fold-off piece formed on at least one of the inner flaps, wherein the tip of the at least one inner flap is one edge of the second fold-off piece, the fold line of the second fold-off piece is positioned along the fold line of the first fold-off piece, and the at least one inner flap is opened such that when the second fold-off piece is pressed into the first fold-off piece, the second fold-off piece folds back in the direction of the fold-off of the first fold-off piece. [Effects of the Invention]

[0007] According to the present invention, when the second folded piece is pressed into the first folded piece, the first and second folded pieces fold back using the fold line as a starting point, with the first folded piece wrapping around the second folded piece. The pressing force acting on the second folded piece in the folding direction prevents unintended folding of at least one of the inner flaps, thus preventing the inner flap from opening sideways. The outer flap, inner flap, first folded piece, and second folded piece create a quadruple layer in the hand grip portion of the handhole, increasing rigidity and reducing strain on the hand. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view of the packaging box according to the first embodiment. [Figure 2] This is a diagram showing the hand hole structure of a comparative example. [Figure 3] This is a plan view of the sheet material according to the first embodiment. [Figure 4] This is an explanatory diagram of the handhole structure of the first embodiment. [Figure 5] This figure shows a modified example of the handhole structure of the first embodiment. [Figure 6] This is an explanatory diagram of the handhole structure of the second embodiment. [Figure 7]It is a figure showing a modification example of the hand hole structure of the second embodiment. [Figure 8] It is an explanatory view of the hand hole structure of the third embodiment. [Figure 9] It is a figure showing a modification example of the hand hole structure of the third embodiment. [Figure 10] It is an explanatory view of the hand hole structure of the fourth embodiment. [Figure 11] It is a plan view of the sheet material of the fifth embodiment. [Figure 12] It is an explanatory view of the hand hole structure of the fifth embodiment. [Figure 13] It is an explanatory view of a modification example of the second folded-back piece of the quadrilateral type. [Figure 14] It is a figure showing a modification example of the second folded-back piece of the quadrilateral type. [Figure 15] It is a figure showing a modification example of the second folded-back piece of the quadrilateral type. [Figure 16] It is an explanatory view of another modification example of the second folded-back piece of the quadrilateral type. [Figure 17] It is a figure showing another modification example of the second folded-back piece of the quadrilateral type. [Figure 18] It is a figure showing another modification example of the second folded-back piece of the quadrilateral type. [Figure 19] It is an explanatory view of a modification example of the second folded-back piece of the triangular type. [Figure 20] It is a figure showing a modification example of the second folded-back piece of the triangular type. [Figure 21] It is an explanatory view of another modification example of the second folded-back piece of the triangular type. [Figure 22] It is a figure showing another modification example of the second folded-back piece of the triangular type.

Modes for Carrying Out the Invention

[0009] Hereinafter, this embodiment will be described with reference to the drawings. Arrows Fr, Rr, L, R, U, and Lo attached to each figure indicate the front side, rear side, left side, right side, upper side, and lower side, respectively, when the packaging box is viewed from the front. In addition, in this embodiment, terms indicating directions and positions are used, but these terms are used for convenience of explanation and do not limit the technical scope of the present invention.

[0010] <First Embodiment> Referring to FIGS. 1 to 3, a packaging box having the handhole structure of the first embodiment will be described. FIG. 1 is a perspective view of the packaging box of the first embodiment. FIG. 2 is an explanatory view of the handhole structure of the comparative example. FIG. 3 is a plan view of the sheet material of the first embodiment. Note that the upper side of FIG. 2 indicates the outer flap, and the lower side of FIG. 2 indicates a pair of inner flaps.

[0011] As shown in FIG. 1, the packaging box 1 is a wraparound case for packaging so as to enclose a plurality of products. The packaging box 1 is provided with an upper wall 11 and a bottom wall 12 facing each other in the vertical direction, and a pair of side walls 13a and 13b facing each other in the front-rear direction. A pair of inner flaps 14a are connected to both side edges in the left-right direction of the front side wall 13a, and a pair of inner flaps 14b are connected to both side edges in the left-right direction of the rear side wall 13b. A pair of outer flaps (outer flaps) 15a are connected to both side edges in the left-right direction of the upper wall 11, and a pair of outer flaps 15b are connected to both side edges in the left-right direction of the bottom wall 12.

[0012] The inner flaps 14a and 14b are folded inside the outer flaps 15a and 15b, and the outer flaps 15a and 15b are adhesively bonded to the inner flaps 14a and 14b with hot melt to form a pair of left and right side walls of the packaging box 1. A first folded piece 21 having a handhole shape (a rounded square shape in this embodiment) is formed on the upper outer flap 15a, and second folded pieces 25a and 25b are formed on the left and right inner flaps 14a and 14b so as to overlap the first folded piece 21 (see FIG. 3). By folding the first folded piece 21 and the second folded pieces 25a and 25b inward, a pair of handholes 30 are formed on a pair of left and right side walls of the packaging box 1.

[0013] Incidentally, in the comparative example handhole structure shown in Figure 2(A), a first handhole-shaped folded-back piece 43 is formed on the outer flap 41. The base end of the first folded-back piece 43 is connected to the outer flap 41 via a fold line La, and the tip 44 and arc-shaped side edges 45 of the first folded-back piece 43 are separated from the outer flap 41. In addition, a second semi-handhole-shaped folded-back piece 46a, 46b is formed on the inner flaps 42a, 42b. The base end of the second folded-back piece 46a, 46b is connected to the inner flaps 42a, 42b via a fold line Lb, and the tip 48a, 48b and arc-shaped side edges 47a, 47b of the second folded-back piece 46a, 46b are separated from the inner flaps 42a, 42b.

[0014] When the first folded piece 43 is divided into a front half and a back half, the second folded piece 46a is positioned on the inside (lower side in the figure) of the front half of the first folded piece 43, and the second folded piece 46b is positioned on the inside of the back half of the first folded piece 43. In addition, the inner flaps 42a and 42b are superimposed on the inside of the outer flap 41, and both sides of the outer flap 41 in the front-rear direction are bonded to the base ends of the inner flaps 42a and 42b with hot melt adhesive 49a and 49b. In this way, the outer flap 41 is fixed to the inner flaps 42a and 42b at a point where the first folded piece 43 and the second folded pieces 46a and 46b are avoided in the front-rear direction.

[0015] As shown in Figure 2(B), when the first folded piece 43 is pushed in, the first folded piece 43 abuts against the second folded pieces 46a and 46b (see Figure 2(A)). At this time, even if the first folded piece 43 is folded properly, the second folded pieces 46a and 46b may not be folded properly. More specifically, the first folded piece 43 is folded with the fold line La as the pivot point, but the second folded pieces 46a and 46b are not folded with the fold line Lb as the pivot point. With the boundary Lc (see Figure 2(A)) between the adhesive and non-adhesive positions of the inner flaps 42a and 42b as the pivot point, the inner flaps 42a and 42b may unintentionally fold in the middle and open both ways.

[0016] When the inner flaps 42a and 42b open from both sides and only the first folded piece 43 is folded back, the hand grip portion of the hand hole becomes double-layered with the outer flap 41 and the first folded piece 43, resulting in insufficient rigidity in the hand grip portion and increased strain on the hand. Therefore, in the packaging box 1 of this embodiment, openings are formed in the inner flaps 14a and 14b so that the second folded pieces 25a and 25b are wrapped around the fold of the first folded piece 21 (see Figure 4). When the first folded piece 21 and the second folded pieces 25a and 25b are properly folded back, the hand grip portion of the hand hole becomes quadruple-layered, increasing rigidity and reducing strain on the hand.

[0017] As shown in Figure 3, the sheet material 5 represents the unfolded state of the packaging box 1, and is formed by applying various processes to a single sheet of corrugated cardboard manufactured by a corrugator. The corrugated cardboard sheet is a double-sided corrugated cardboard sheet in which a front liner and a back liner are laminated to a corrugated core 6. Note that Figure 3 shows the corrugated cardboard sheet as seen from the front liner side. In the following explanation, the direction in which the peaks of the corrugations of the core 6 of the corrugated cardboard sheet extend will be referred to as the "corrugation direction X," and the direction perpendicular to the core 6 of the corrugated cardboard sheet will be referred to as the "flow direction Y."

[0018] The sheet material 5 has a roughly rectangular joint 16, a rear side wall 13b, a bottom wall 12, a front side wall 13a, and a top wall 11 arranged in one direction in the step direction X via fold lines L1-L4. A pair of roughly rectangular inner flaps 14b are connected to both sides of the rear side wall 13b in the flow direction Y via fold line L5, and a pair of roughly rectangular outer flaps 15b are connected to both ends of the bottom wall 12 in the flow direction Y via fold line L6. A pair of roughly rectangular inner flaps 14a are connected to both sides of the front side wall 13a in the flow direction Y via fold line L7, and a pair of roughly rectangular outer flaps 15a are connected to both sides of the top wall 11 in the flow direction Y via fold line L8.

[0019] A pair of first folded pieces 21 are formed on a pair of outer flaps 15a. A pair of second folded pieces 25a are formed on one side of the inner flap 14a in the step direction X, and a pair of second folded pieces 25b are formed on the other side of the inner flap 14b in the step direction X. The first folded pieces 21 are connected to the outer flap 15a via a fold line L9, and the second folded pieces 25a and 25b are connected to the inner flaps 14a and 14b via fold lines L10 and L11. The second folded pieces 25a and 25b are formed in positions corresponding to the first folded pieces 21 when the packaging box 1 is assembled. The first folded pieces 21 and the second folded pieces 25a and 25b form a hand-hole structure.

[0020] Referring to Figure 4, the hand-hole structure of the first embodiment will be described. Figure 4 is an explanatory diagram of the hand-hole structure of the first embodiment. Note that the upper part of Figure 4 shows the outer flap, and the lower part of Figure 4 shows the pair of inner flaps. The packaging box contains a bottle as the product. Furthermore, the hand-holes of the pair of inner flaps, which are formed by folding back a pair of second folded pieces, are larger than the hand-holes of the outer flap, which are formed by folding back a first folded piece. That is, the height and width dimensions of the hand-holes of the pair of inner flaps are larger than the height and width dimensions of the hand-holes of the outer flap.

[0021] As shown in Figure 4(A), in the hand-hole structure of the packaging box 1, a first hand-hole shaped folded-back piece 21 is formed in the central part of the outer flap 15a. The base end of the first folded-back piece 21 is connected to the outer flap 15a via a fold line L9, and the tip 22 and arc-shaped side edges 23 of the first folded-back piece 21 are separated from the outer flap 15a. In addition, rectangular second folded-back pieces 25a and 25b are formed on the tip sides of the inner flaps 14a and 14b. The base ends of the second folded-back pieces 25a and 25b are connected to the inner flaps 14a and 14b via fold lines L10 and L11, and the tips 28a and 28b of the second folded-back pieces 25a and 25b are separated from the inner flaps 14a and 14b.

[0022] The tips of the inner flaps 14a and 14b are directed toward the center of the packaging box 1, and the second folded pieces 25a and 25b have one side edge 26a and 26b of the tips of the inner flaps 14a and 14b. In addition, the inner flaps 14a and 14b have openings where they are adjacent to the other side edges 27a and 27b of the second folded pieces 25a and 25b. That is, the second folded pieces 25a and 25b are formed into a rectangular tab shape by cutting off the semicircular portions at both ends from a half-handhole shape which is obtained by dividing the handhole shape in the front-to-back direction into two equal parts. The openings 29a and 29b separate the other side edges 27a and 27b of the second folded pieces 25a and 25b from the inner flaps 14a and 14b.

[0023] The second folded piece 25a overlaps the inside of one half (front half) of the first folded piece 21, and the second folded piece 25b overlaps the inside of the other half (rear half) of the first folded piece 21. The fold lines L10 and L11 of the second folded pieces 25a and 25b are located along the fold line L9 of the first folded piece 21. Hot melt 31a is applied to the base end (front side) of the semicircular opening 29a of the inner flap 14a, and hot melt 31b is applied to the base end (rear side) of the semicircular opening 29b of the inner flap 14b. Both sides (both sides in the front-rear direction) of the outer flap 15a are bonded to the base ends of the inner flaps 14a and 14b with hot melt 31a and 31b.

[0024] As shown in Figure 4(B), when the first folded piece 21 is pressed in, it abuts against the second folded pieces 25a and 25b. At this time, since the second folded pieces 25a and 25b are separated from the inner flaps 14a and 14b with the openings 29a and 29b in between, the pressing force of the first folded piece 21 is not easily transmitted to the inner flaps 14a and 14b via the second folded pieces 25a and 25b. The inner flaps 14a and 14b do not fold in the middle with the boundary between the bonded and non-bonded positions of the inner flaps 14a and 14b as a fulcrum. The second folded pieces 25a and 25b are folded back in the direction of the first folded piece 21 with the fold lines L10 and L11 as fulcrums.

[0025] The first folded piece 21 is folded over so as to wrap around the second folded pieces 25a and 25b, forming hand holes 30 on the left and right sides of the packaging box 1. The handle portion of the hand holes 30 is reinforced by overlapping the outer flap 15a, inner flaps 14a and 14b, the second folded pieces 25a and 25b, and the first folded piece 21 from the outside to the inside of the packaging box 1. The first folded piece 21 and the second folded pieces 25a and 25b are positioned between the neck portions of adjacent bottles 32, so that the first folded piece 21 and the second folded pieces 25a and 25b do not interfere with the bottles 32. In addition, because the fold line L9-L11 is horizontal, the upper edge of the hand holes 30 is horizontal and easy to hold.

[0026] As described above, according to the first embodiment, when the second folded pieces 25a and 25b are pressed into the first folded piece 21, the first folded piece 21 is folded back so as to wrap around the second folded pieces 25a and 25b. The pressing force acting on the second folded pieces 25a and 25b in the folding direction prevents unintended folding of the inner flaps 14a and 14b, thus preventing the inner flaps 14a and 14b from opening both sides. The grip portion of the hand hole 30 is quadrupled, increasing its rigidity and reducing the burden on the hand.

[0027] In the first embodiment, an example is shown in which the portion adjacent to the other side edge of the second folded piece is open, and the tip of the second folded piece is separated from the pair of inner flaps. The shape of the second folded piece and the direction of extension of the fold line can be changed as appropriate. A modified example of the hand hole structure of the first embodiment will be described below with reference to Figure 5. Figure 5 is a diagram showing a modified example of the hand hole structure of the first embodiment.

[0028] For example, as shown in Figure 5(A), the second folded pieces 25a and 25b may be formed in a rectangular shape, and the second folded pieces 25a and 25b may be folded using the fold lines L10 and L11 as pivot points. In this case, it is preferable that the distance C between the other side edges 27a and 27b of the second folded pieces 25a and 25b is formed to be 0.7 times or less the width A of the first folded piece 21 (see Figure 4).

[0029] As shown in Figure 5(B), the second folded pieces 25a and 25b may be formed in a trapezoidal shape, and the second folded pieces 25a and 25b may be folded back using the fold lines L10 and L11 as pivot points. In this case, it is preferable that the total length D of the tips 28a and 28b of the second folded pieces 25a and 25b is formed to be 0.7 times or more and 1.1 times or less the width A of the first folded piece 21.

[0030] As shown in Figure 5(C), the second folded pieces 25a and 25b may be formed in a triangular shape, and the second folded pieces 25a and 25b may be folded using the fold lines L10 and L11 as pivot points. The first folded piece 21 comes into contact with the vicinity of the vertices of the second folded pieces 25a and 25b, making it easier for the second folded pieces 25a and 25b to fold along the fold lines L10 and L11. In this case, it is preferable that the distance E between the vertices of the second folded pieces 25a and 25b is formed to be 0.4 times or more the width A of the first folded piece 21.

[0031] As shown in Figure 5(D), the second folded pieces 25a and 25b are formed in a rectangular shape, and may be folded back using the fold lines L10 and L11 as pivot points. The fold lines L10 and L11 intersect diagonally with the step direction X (see Figure 3). The diagonal intersection of the step of the core 6 (see Figure 3) and the fold lines L10 and L11 makes it difficult for the inner flaps 14a and 14b to tear even when the second folded pieces 25a and 25b are folded back. In this case, the fold line of the first folded piece is also formed diagonally.

[0032] As shown in Figure 5(E), the second folded pieces 25a and 25b may be formed in a triangular shape, and the second folded pieces 25a and 25b may be folded using the fold lines L10 and L11 as pivot points. The fold lines L10 and L11 intersect diagonally with the step direction X. Because the second folded pieces 25a and 25b are triangular in shape and the fold lines L10 and L11 are inclined, the second folded pieces 25a and 25b become easier to fold, and the inner flaps 14a and 14b become less likely to tear. In this case, the fold line of the first folded piece is also formed diagonally.

[0033] <Second Embodiment> Referring to Figure 6, the handhole structure of the second embodiment will be described. The handhole structure of the second embodiment differs from the handhole structure of the first embodiment in that the lower part of the second folded piece is open. Therefore, the same reference numerals are used for components corresponding to those of the first embodiment, and their description is omitted. Figure 6 is an explanatory diagram of the handhole structure of the second embodiment. Note that the upper part of Figure 6 shows the outer flap, and the lower part of Figure 6 shows the pair of inner flaps.

[0034] As shown in Figure 6(A), a first folded-back piece 21 in the shape of a handhole is formed in the central part of the outer flap 15a. The base end of the first folded-back piece 21 is connected to the outer flap 15a via a fold line L9, and the tip 22 and arc-shaped side edges 23 of the first folded-back piece 21 are separated from the outer flap 15a. In addition, second folded-back pieces 25a and 25b are formed on the tip sides of the inner flaps 14a and 14b. The second folded-back pieces 25a and 25b are formed in a shape like a rounded rectangle divided into four equal parts vertically and horizontally, and the base ends of the second folded-back pieces 25a and 25b are connected to the inner flaps 14a and 14b via fold lines L10 and L11.

[0035] The second folded pieces 25a and 25b have one side edge 26a and 26b at the tip of the inner flaps 14a and 14b, and the other arc-shaped side edge 27a and 27b of the second folded pieces 25a and 25b is separated from the inner flaps 14a and 14b. In addition, the inner flaps 14a and 14b have openings where they extend beyond the tips 28a and 28b of the second folded pieces 25a and 25b. That is, the second folded pieces 25a and 25b are formed into a tab shape by cutting off the lower half of a half-hole shape which is obtained by dividing the hand-hole shape in the front-to-back direction. The openings 29a and 29b separate the tips 28a and 28b of the second folded pieces 25a and 25b from the inner flaps 14a and 14b.

[0036] The second folded piece 25a overlaps the inside of one half (front half) of the first folded piece 21, and the second folded piece 25b overlaps the inside of the other half (rear half) of the first folded piece 21. The fold lines L10 and L11 of the second folded pieces 25a and 25b are located along the fold line L9 of the first folded piece 21. Hot melt 31a is applied to the base end (front side) of the inner flap 14a relative to the second folded piece 25a, and hot melt 31b is applied to the base end (rear side) of the inner flap 14b relative to the second folded piece 25b. Both sides (both sides in the front-rear direction) of the outer flap 15a are bonded to the base ends of the inner flaps 14a and 14b with hot melt 31a and 31b.

[0037] As shown in Figure 6(B), when the first folded piece 21 is pushed in, it abuts against the second folded pieces 25a and 25b. At this time, when the first folded piece 21 is folded in partway, the second folded pieces 25a and 25b are pushed against the first folded piece 21, so an upward pressing force acts on the second folded pieces 25a and 25b, which is the folding direction. The inner flaps 14a and 14b do not fold in the middle, with the boundary between the adhesive and non-adhesive positions of the inner flaps 14a and 14b as the pivot point. The second folded pieces 25a and 25b are folded in the folding direction of the first folded piece 21, with the fold lines L10 and L11 as the pivot points.

[0038] The first folded flap 21 is folded over so as to wrap around the second folded flap 25a and 25b, forming hand holes 30 on the left and right sides of the packaging box. The handle portion of the hand holes 30 is reinforced by overlapping the outer flap 15a, inner flaps 14a and 14b, the second folded flap 25a and 25b, and the first folded flap 21 from the outside to the inside of the packaging box. In addition, because the fold lines L9-L11 are horizontal, the upper edge of the hand holes 30 is formed to be horizontal and easy to hold. Preferably, the length F from the fold lines L10 and L11 of the second folded flap 25a and 25b to the tip 28a and 28b is formed to be 0.6 times or less the length B from the fold line L9 to the tip 22 of the first folded flap 21.

[0039] As described above, in the second embodiment as well, the pressing force applied to the second folded pieces 25a and 25b in the folding direction suppresses the folding of the inner flaps 14a and 14b in the middle, preventing them from opening both ways. Therefore, the grip portion of the hand hole becomes quadruple-layered, increasing its rigidity and reducing the burden on the hand.

[0040] In the second embodiment, an example is shown in which the portion beyond the tip of the second folded piece is open, and the other side edge of the second folded piece is separated from the inner flap. The shape of the second folded piece and the direction of extension of the fold line can be changed as appropriate. A modified example of the hand hole structure of the second embodiment will be described below with reference to Figure 7. Figure 7 is a diagram showing a modified example of the hand hole structure of the second embodiment.

[0041] For example, as shown in Figure 7(A), the second folded pieces 25a and 25b may be formed in a trapezoidal shape, and the second folded pieces 25a and 25b may be folded back using the fold lines L10 and L11 as pivot points. In this case, it is preferable that the total length G of the tips 28a and 28b of the second folded pieces 25a and 25b is formed to be 0.7 times or more and 0.9 times or less the width A of the first folded piece 21 (see Figure 6).

[0042] As shown in Figure 7(B), the second folded pieces 25a and 25b may be formed in a triangular shape, and the second folded pieces 25a and 25b may be folded using the fold lines L10 and L11 as pivot points. The first folded piece 21 comes into contact with the vicinity of the vertices of the second folded pieces 25a and 25b, making it easier for the second folded pieces 25a and 25b to fold along the fold lines L10 and L11. In this case, it is preferable that the distance H between the vertices of the second folded pieces 25a and 25b is formed to be 0.4 times or more the width A of the first folded piece 21. Furthermore, it is preferable that the length I from the fold lines L10 and L11 to the tip of the second folded pieces 25a and 25b is formed to be 0.6 times or less the length B from the fold line L9 to the tip 22 of the first folded piece 21.

[0043] As shown in Figure 7(C), the second folded pieces 25a and 25b are formed in a rectangular shape, and may be folded back using the fold lines L10 and L11 as pivot points. The fold lines L10 and L11 intersect diagonally with the step direction X (see Figure 3). The diagonal intersection of the step of the core 6 (see Figure 3) and the fold lines L10 and L11 makes it difficult for the inner flaps 14a and 14b to tear even when the second folded pieces 25a and 25b are folded back. In this case, the fold line of the first folded piece is also formed diagonally.

[0044] As shown in Figure 7(D), the second folded pieces 25a and 25b may be formed in a triangular shape, and the second folded pieces 25a and 25b may be folded using the fold lines L10 and L11 as pivot points. The fold lines L10 and L11 intersect diagonally with the step direction X. Because the second folded pieces 25a and 25b are triangular in shape and the fold lines L10 and L11 are inclined, the second folded pieces 25a and 25b become easier to fold, and the inner flaps 14a and 14b become less likely to tear. In this case, the fold line of the first folded piece is also formed diagonally.

[0045] <Third Embodiment> Referring to Figure 8, the handhole structure of the third embodiment will be described. The handhole structure of the third embodiment differs from the handhole structure of the first embodiment in that the sides and bottom of the second folded piece are open. Therefore, the same reference numerals are used for components corresponding to those of the first embodiment, and their description is omitted. Figure 8 is an explanatory diagram of the handhole structure of the third embodiment. Note that the upper part of Figure 8 shows the outer flap, and the lower part of Figure 8 shows the pair of inner flaps.

[0046] As shown in Figure 8(A), a first folded-back piece 21 in the shape of a handhole is formed in the central part of the outer flap 15a. The base end of the first folded-back piece 21 is connected to the outer flap 15a via a fold line L9, and the tip 22 and arc-shaped side edges 23 of the first folded-back piece 21 are separated from the outer flap 15a. In addition, rectangular second folded-back pieces 25a and 25b are formed on the tip sides of the inner flaps 14a and 14b. The base ends of the second folded-back pieces 25a and 25b are connected to the inner flaps 14a and 14b via fold lines L10 and L11, and the second folded-back pieces 25a and 25b form one side edge 26a and 26b of the tip of the inner flaps 14a and 14b.

[0047] Furthermore, the inner flaps 14a and 14b are open at locations adjacent to the other side edges 27a and 27b of the second folded pieces 25a and 25b. In addition, the inner flaps 14a and 14b are open at locations beyond the tips 28a and 28b of the second folded pieces 25a and 25b. That is, the second folded pieces 25a and 25b are formed into a rectangular tab shape by cutting off the semicircular portions at both ends and the lower half from a half-handhole shape which is obtained by dividing the handhole shape in the front-to-back direction. The openings 29a and 29b cause the other side edges 27a and 27b of the second folded pieces 25a and 25b to separate from the inner flaps 14a and 14b, and the tips 28a and 28b to separate from the inner flaps 14a and 14b.

[0048] The second folded piece 25a overlaps the inside of one half (front half) of the first folded piece 21, and the second folded piece 25b overlaps the inside of the other half (rear half) of the first folded piece 21. The fold lines L10 and L11 of the second folded pieces 25a and 25b are located along the fold line L9 of the first folded piece 21. Hot melt 31a is applied to the base end (front side) of the opening 29a of the inner flap 14a, and hot melt 31b is applied to the base end (rear side) of the opening 29b of the inner flap 14b. Both sides (both sides in the front-rear direction) of the outer flap 15a are bonded to the base ends of the inner flaps 14a and 14b with hot melt 31a and 31b.

[0049] As shown in Figure 8(B), when the first folded piece 21 is pressed in, it abuts against the second folded pieces 25a and 25b. At this time, the pressing force of the first folded piece 21 is not transmitted to the inner flaps 14a and 14b, and when the first folded piece 21 is folded in partway, the second folded pieces 25a and 25b are pressed against the first folded piece 21, so that an upward pressing force acts on the second folded pieces 25a and 25b, which is the folding direction. The inner flaps 14a and 14b do not fold in the middle, with the boundary between the bonded and non-bonded positions of the inner flaps 14a and 14b as the pivot point. With the fold lines L10 and L11 as pivot points, the second folded pieces 25a and 25b are folded in the folding direction of the first folded piece 21.

[0050] The first folded piece 21 is folded over so as to wrap around the second folded pieces 25a and 25b, forming hand holes 30 on the left and right sides of the packaging box. The handle portion of the hand holes 30 is reinforced by overlapping the outer flap 15a, inner flaps 14a and 14b, the second folded pieces 25a and 25b, and the first folded piece 21 from the outside to the inside of the packaging box. In addition, because the fold line L9-L11 is horizontal, the upper edge of the hand holes 30 is formed to be horizontal and easy to hold. Preferably, the distance J between the other side edges 27a and 27b of the second folded pieces 25a and 25b is formed to be 0.7 times or less the width A of the first folded piece 21. Preferably, the length K from the fold lines L10, L11 to the tip 28a, 28b of the second folded pieces 25a, 25b is formed to be 0.6 times or less the length B from the fold line L9 to the tip 22 of the first folded piece 21.

[0051] As described above, in the third embodiment as well, the pressing force applied to the second folded pieces 25a and 25b in the folding direction suppresses the folding of the inner flaps 14a and 14b in the middle, preventing them from opening both ways. Therefore, the hand grip portion of the hand hole becomes quadruple, increasing its rigidity and reducing the burden on the hand.

[0052] In the third embodiment, an example is shown in which the area adjacent to the other end of the second folded piece and the area beyond the tip of the second folded piece are open. The shape of the second folded piece and the direction of extension of the fold line can be changed as appropriate. A modified example of the hand hole structure of the third embodiment will be described below with reference to Figure 9. Figure 9 is a diagram showing a modified example of the hand hole structure of the third embodiment.

[0053] For example, as shown in Figure 9(A), the second folded pieces 25a and 25b may be formed in a trapezoidal shape, and the second folded pieces 25a and 25b may be folded back using the fold lines L10 and L11 as pivot points. In this case, it is preferable that the total length L of the tips 28a and 28b of the second folded pieces 25a and 25b is formed to be 0.6 times or more the width A of the first folded piece 21 (see Figure 8).

[0054] As shown in Figure 9(B), the second folded pieces 25a and 25b are formed in a triangular shape, and the second folded pieces 25a and 25b may be folded using the fold lines L10 and L11 as pivot points. The first folded piece 21 strikes the vicinity of the vertices of the second folded pieces 25a and 25b, making it easier for the second folded pieces 25a and 25b to fold along the fold lines L10 and L11.

[0055] As shown in Figure 9(C), the second folded pieces 25a and 25b are formed in a rectangular shape, and may be folded back using the fold lines L10 and L11 as pivot points. The fold lines L10 and L11 intersect diagonally with the step direction X (see Figure 3). The diagonal intersection of the step of the core 6 (see Figure 3) and the fold lines L10 and L11 makes it difficult for the inner flaps 14a and 14b to tear even when the second folded pieces 25a and 25b are folded back. In this case, the fold line of the first folded piece is also formed diagonally.

[0056] As shown in Figure 9(D), the second folded pieces 25a and 25b may be formed in a triangular shape, and the second folded pieces 25a and 25b may be folded using the fold lines L10 and L11 as pivot points. The fold lines L10 and L11 intersect diagonally with the step direction X. Because the second folded pieces 25a and 25b are triangular in shape and the fold lines L10 and L11 are inclined, the second folded pieces 25a and 25b become easier to fold, and the inner flaps 14a and 14b become less likely to tear. In this case, the fold line of the first folded piece is also formed diagonally.

[0057] <Fourth Embodiment> Referring to Figure 10, the handhole structure of the fourth embodiment will be described. The handhole structure of the fourth embodiment differs from the handhole structure of the first embodiment in that an opening is made between a pair of second folded pieces. Therefore, the same reference numerals are used for components corresponding to those of the first embodiment, and their description is omitted. Figure 10 is an explanatory diagram of the handhole structure of the fourth embodiment. Note that the upper part of Figure 10 shows the outer flap, and the lower part of Figure 10 shows the pair of inner flaps.

[0058] As shown in Figure 10(A), a first folded-back piece 21 in the shape of a handhole is formed in the central part of the outer flap 15a. The base end of the first folded-back piece 21 is connected to the outer flap 15a via a fold line L9, and the tip 22 and both arc-shaped side edges 23 of the first folded-back piece 21 are separated from the outer flap 15a. In addition, second folded-back pieces 25a and 25b are formed on the tip sides of the inner flaps 14a and 14b. The base ends of the second folded-back pieces 25a and 25b are connected to the inner flaps 14a and 14b via fold lines L10 and L11. The tips of the inner flaps 14a and 14b are partially cut out, creating an opening between the second folded-back pieces 25a and 25b.

[0059] The edges 26a, 26b of one side of the second folded pieces 25a, 25b are inclined downward so as to move away from each other. The other arc-shaped edges 27a, 27b of the second folded pieces 25a, 25b are separated from the inner flaps 14a, 14b. In other words, the second folded pieces 25a, 25b are formed in a tab shape, which is a half-handhole shape obtained by dividing the handhole shape in the front-to-back direction into two equal parts, with a triangular section cut out in the middle. The openings 29a, 29b are formed to widen downwards. As a result, the central part of the first folded piece 21 does not come into contact with the second folded pieces 25a, 25b, while the ends of the first folded piece 21 come into contact with the second folded pieces 25a, 25b.

[0060] The second folded piece 25a overlaps the inside of one half (front half) of the first folded piece 21, and the second folded piece 25b overlaps the inside of the other half (rear half) of the first folded piece 21. The fold lines L10 and L11 of the second folded pieces 25a and 25b are located along the fold line L9 of the first folded piece 21. Hot melt 31a is applied to the base end (front side) of the inner flap 14a relative to the second folded piece 25a, and hot melt 31b is applied to the base end (rear side) of the inner flap 14b relative to the second folded piece 25b. Both sides (both sides in the front-rear direction) of the outer flap 15a are bonded to the base ends of the inner flaps 14a and 14b with hot melt 31a and 31b.

[0061] As shown in Figure 10(B), when the first folded piece 21 is pushed in, it abuts against the second folded pieces 25a and 25b. At this time, the first folded piece 21 does not push between the second folded pieces 25a and 25b, i.e., the leading edges of the inner flaps 14a and 14b. Because no pressing force is applied to the leading edges of the inner flaps 14a and 14b, the inner flaps 14a and 14b do not fold in the middle with the boundary between the bonded and non-bonded positions of the inner flaps 14a and 14b as the pivot point. The second folded pieces 25a and 25b are folded back in the direction of the first folded piece 21, with the fold lines L10 and L11 as the pivot points.

[0062] The first folded flap 21 is folded over so as to wrap around the second folded flap 25a and 25b, forming hand holes on the left and right sides of the packaging box. The handle portion of the hand hole is reinforced by overlapping the outer flap 15a, inner flaps 14a and 14b, the second folded flap 25a and 25b, and the first folded flap 21 from the outside to the inside of the packaging box. In addition, because the fold lines L9-L11 are horizontal, the upper edge of the hand hole 30 is formed horizontally for easy gripping.

[0063] As described above, in the fourth embodiment as well, the pressing force applied to the second folded pieces 25a and 25b in the folding direction suppresses the folding of the inner flaps 14a and 14b in the middle, preventing them from opening both ways. Therefore, the hand grip portion of the hand hole becomes quadruple-layered, increasing its rigidity and reducing the burden on the hand.

[0064] In the fourth embodiment, an example is shown in which there is an opening between the second folded pieces. As in the first to third embodiments, the opening may be located adjacent to the other end of the second folded piece and / or beyond the tip of the second folded piece. Furthermore, the shape of the second folded piece and the direction of the fold line extension can be changed as appropriate.

[0065] <Fifth Embodiment> The hand-hole structure of the fifth embodiment will be described with reference to Figures 11 and 12. The hand-hole structure of the fifth embodiment differs from that of the first embodiment mainly in the shape of the hand-holes. Therefore, components corresponding to those of the first embodiment are given the same reference numerals and their descriptions are omitted. Figure 11 is a plan view of the sheet material of the fifth embodiment. Figure 12 is an explanatory diagram of the hand-hole structure of the fifth embodiment. Note that the upper part of Figure 12 shows the outer flap, and the lower part of Figure 12 shows a pair of inner flaps. Also, the packaging box contains bottles as the product.

[0066] As shown in Figure 11, the sheet material 5 has a roughly rectangular joint 16, a rear side wall 13b, a bottom wall 12, a front side wall 13a, and a top wall 11 arranged in one direction in the step direction X via fold lines L1-L4. A pair of roughly rectangular inner flaps 14b are connected to both sides of the rear side wall 13b in the flow direction Y via fold line L5, and a pair of roughly rectangular outer flaps 15b are connected to both ends of the bottom wall 12 in the flow direction Y via fold line L6. A pair of roughly rectangular inner flaps 14a are connected to both sides of the front side wall 13a in the flow direction Y via fold line L7, and a pair of roughly rectangular outer flaps 15a are connected to both sides of the top wall 11 in the flow direction Y via fold line L8.

[0067] A pair of first folded pieces 21 are formed on a pair of outer flaps 15a. A pair of second folded pieces 25a are formed on one side of the inner flap 14a in the step direction X, and a pair of second folded pieces 25b are formed on the other side of the inner flap 14b in the step direction X. The first folded pieces 21 are connected to the outer flap 15a via fold line L9, and the second folded pieces 25a and 25b are connected to the inner flaps 14a and 14b via fold lines L10 and L11. The second folded pieces 25a and 25b are formed in positions corresponding to the first folded pieces 21 when the packaging box is assembled. The first folded pieces 21 and the second folded pieces 25a and 25b form a hand-hole structure. Fold lines L1-L9 are formed by creases, and fold lines L10 and L11 are formed by perforations.

[0068] As shown in Figure 12(A), a first folded-back piece 21 in the shape of a handhole is formed in the central part of the outer flap 15a. The base end of the first folded-back piece 21 is parallel to the step direction X (see Figure 11), and the tip 22 of the first folded-back piece 21 is curved downwards. The base end side of the first folded-back piece 21 is connected to the outer flap 15a via the fold line L9, and the tip 22 and both side edges 23 of the first folded-back piece 21 are separated from the outer flap 15a. In addition, the tips of the inner flaps 14a and 14b are cut out to form triangular second folded-back pieces 25a and 25b. The base ends of the second folded-back pieces 25a and 25b are connected to the inner flaps 14a and 14b via the fold lines L10 and L11.

[0069] The tips of the inner flaps 14a and 14b are notched, so that the inner flaps 14a and 14b are open between the second folded pieces 25a and 25b at the points adjacent to the other side edges 27a and 27b of the second folded pieces 25a and 25b, and beyond the tips 28a and 28b of the second folded pieces 25a and 25b. As a result, the triangular second folded pieces 25a and 25b are formed to protrude from the fold lines L10 and L11 of the inner flaps 14a and 14b toward the hand hole. The openings 29a and 29b cause the other side edges 27a and 27b of the second folded pieces 25a and 25b to be separated from the inner flaps 14a and 14b, and the tips 28a and 28b to be separated from the inner flaps 14a and 14b.

[0070] The second folded piece 25a overlaps the inside of one half (front half) of the first folded piece 21, and the second folded piece 25b overlaps the inside of the other half (rear half) of the first folded piece 21. The fold lines L10 and L11 of the second folded pieces 25a and 25b are located along the fold line L9 of the first folded piece 21. Hot melt 31a is applied to the base end (front side) of the semicircular opening 29a of the inner flap 14a, and hot melt 31b is applied to the base end (rear side) of the semicircular opening 29b of the inner flap 14b. Both sides (both sides in the front-rear direction) of the outer flap 15a are bonded to the base ends of the inner flaps 14a and 14b with hot melt 31a and 31b.

[0071] As shown in Figure 12(B), when the first folded piece 21 is pressed in, it abuts against the second folded pieces 25a and 25b. At this time, since the second folded pieces 25a and 25b are completely separated from the inner flaps 14a and 14b except for their base ends, an upward pressing force acts on the second folded pieces 25a and 25b, which is the folding direction. The inner flaps 14a and 14b do not fold in the middle, with the boundary between the adhesive and non-adhesive positions of the inner flaps 14a and 14b as the pivot point. With the fold lines L10 and L11 as pivot points, the second folded pieces 25a and 25b are folded in the folding direction of the first folded piece 21.

[0072] The first folded flap 21 is folded over so as to wrap around the second folded flap 25a and 25b, forming hand holes on the left and right sides of the packaging box. The handle portion of the hand hole is reinforced by overlapping the outer flap 15a, inner flaps 14a and 14b, the second folded flap 25a and 25b, and the first folded flap 21 from the outside to the inside of the packaging box. The first folded flap 21 and the second folded flap 25a and 25b are positioned between the neck portions of adjacent bottles 32, so that the first folded flap 21 and the second folded flap 25a and 25b do not interfere with the bottles 32. In addition, because the fold line L9-L11 is horizontal, the upper edge of the hand hole 30 is horizontal and easy to hold.

[0073] As described above, in the fifth embodiment as well, the pressing force applied to the second folded pieces 25a and 25b in the folding direction suppresses the folding of the inner flaps 14a and 14b in the middle, preventing them from opening both ways. Therefore, the hand grip portion of the hand hole becomes quadruple, increasing its rigidity and reducing the burden on the hand.

[0074] <Variation> Modifying the second folded piece will be explained with reference to Figures 13 to 22. Figure 13 is an explanatory diagram of a modified rectangular type of the second folded piece. Figures 14 and 15 show modified rectangular type of the second folded piece. Figure 16 is an explanatory diagram of another modified rectangular type of the second folded piece. Figures 17 and 18 show other modified rectangular type of the second folded piece. Figure 19 is an explanatory diagram of a modified triangular type of the second folded piece. Figure 20 shows a modified triangular type of the second folded piece. Figure 21 is an explanatory diagram of another modified triangular type of the second folded piece. Figure 22 shows another modified triangular type of the second folded piece.

[0075] As shown in Figures 13(A) and (B), the second folded pieces 25a and 25b are formed in a square shape, and the tips of the second folded pieces 25a and 25b are in contact with the lower edge of the rounded square hand hole. The base end positions P1 and P2 may be changed when the base end position of one side edge 26a and 26b of the second folded pieces 25a and 25b is P1 and the base end position of the other side edge 27a and 27b of the second folded pieces 25a and 25b is P2. Also, the angles θ1 and θ2 may be changed when the angle of one side edge 26a and 26b with respect to the fold lines L10 and L11 is θ1 and the angle of the other side edge 27a and 27b with respect to the fold lines L10 and L11 is θ2.

[0076] The base end positions P1 and P2 may be positioned midway along the upper edge of the hand hole (see Figure 13(A)), or they may be positioned at one end and the other end of the upper edge of the hand hole (see Figure 13(B)). Alternatively, base end position P2 may be positioned on the arc-shaped side edge of the hand hole. In this case, an incision is made from the other end of the fold lines L10 and L11 to base end position P2. The angle θ1 of one side edge 26a, 26b may vary from obtuse, right, or acute (right angle in Figure 13), and the angle θ2 of the other side edge 27a, 27b may vary from obtuse, right, or acute (acute angle in Figure 13).

[0077] For example, as shown in Figures 14(A) to 14(D), the area adjacent to the other side edges 27a and 27b may not be open, and the base end position P1 and angle θ1 of one side edge 26a and 26b may be changed. As shown in Figures 14(E) to 14(I), the base end position P2 of the other side edges 27a and 27b may be located at the other end of the upper edge of the hand hole, the angle θ2 of the other side edges 27a and 27b may be obtuse, and the base end position P1 and angle θ1 of one side edge 26a and 26b may be changed. As shown in Figures 14(J) to 14(N), the base end position P2 of the other side edges 27a and 27b may be located at the other end of the upper edge of the hand hole, the angle θ2 of the other side edges 27a and 27b may be right, and the base end position P1 and angle θ1 of one side edge 26a and 26b may be changed. As shown in Figures 14(O)-14(S), the base end position P2 of the other side edges 27a and 27b is located at the other end of the upper edge of the hand hole, the angle θ2 of the other side edges 27a and 27b is acute, and the base end position P1 and angle θ1 of the one side edge 26a and 26b may be changed.

[0078] As shown in Figures 15(A)-15(E), the base end position P2 of the other side edges 27a and 27b may be located on the arc-shaped side edge of the hand hole, the angle θ2 of the other side edges 27a and 27b may be acute, and the base end position P1 and angle θ1 of the one side edge 26a and 26b may vary. As shown in Figures 15(F)-15(J), the base end position P2 of the other side edges 27a and 27b may be located in the middle of the upper edge of the hand hole, the angle θ2 of the other side edges 27a and 27b may be obtuse, and the base end position P1 and angle θ1 of the one side edge 26a and 26b may vary. As shown in Figures 15(K)-15(O), the base end position P2 of the other side edge 27a, 27b is located midway along the upper edge of the hand hole, the angle θ2 of the other side edge 27a, 27b is a right angle, and the base end position P1 and angle θ1 of the one side edge 26a, 26b may vary. As shown in Figures 15(P)-15(T), the base end position P2 of the other side edge 27a, 27b is located midway along the upper edge of the hand hole, the angle θ2 of the other side edge 27a, 27b is an acute angle, and the base end position P1 and angle θ1 of the one side edge 26a, 26b may vary.

[0079] As shown in Figures 16(A) and (B), the second folded pieces 25a and 25b are formed in a square shape, and the tips of the second folded pieces 25a and 25b are separated from the lower edge of the rounded square hand hole. The base end positions P1 and P2 may be changed when the base end position of one side edge 26a and 26b of the second folded pieces 25a and 25b is P1 and the base end position of the other side edge 27a and 27b of the second folded pieces 25a and 25b is P2. Also, the angles θ1 and θ2 may be changed when the angle of one side edge 26a and 26b with respect to the fold lines L10 and L11 is θ1 and the angle of the other side edge 27a and 27b with respect to the fold lines L10 and L11 is θ2.

[0080] For example, as shown in Figures 17(A) to 17(E), the area adjacent to the other side edges 27a and 27b may not be open, and the base end position P1 and angle θ1 of one side edge 26a and 26b may be changed. As shown in Figures 17(F) to 17(J), the base end position P2 of the other side edges 27a and 27b may be located at the other end of the upper edge of the hand hole, the angle θ2 of the other side edges 27a and 27b may be obtuse, and the base end position P1 and angle θ1 of one side edge 26a and 26b may be changed. As shown in Figures 17(K) to 17(O), the base end position P2 of the other side edges 27a and 27b may be located at the other end of the upper edge of the hand hole, the angle θ2 of the other side edges 27a and 27b may be right, and the base end position P1 and angle θ1 of one side edge 26a and 26b may be changed. As shown in Figures 17(P)-17(T), the base end position P2 of the other side edges 27a and 27b is located at the other end of the upper edge of the hand hole, the angle θ2 of the other side edges 27a and 27b is acute, and the base end position P1 and angle θ1 of the one side edge 26a and 26b may be changed.

[0081] As shown in Figures 18(A)-18(E), the base end position P2 of the other side edges 27a and 27b may be located on the arc-shaped side edge of the hand hole, the angle θ2 of the other side edges 27a and 27b may be acute, and the base end position P1 and angle θ1 of the one side edge 26a and 26b may vary. As shown in Figures 18(F)-18(J), the base end position P2 of the other side edges 27a and 27b may be located in the middle of the upper edge of the hand hole, the angle θ2 of the other side edges 27a and 27b may be obtuse, and the base end position P1 and angle θ1 of the one side edge 26a and 26b may vary. As shown in Figures 18(K)-18(O), the base end position P2 of the other side edge 27a, 27b is located midway along the upper edge of the hand hole, the angle θ2 of the other side edge 27a, 27b is a right angle, and the base end position P1 and angle θ1 of the one side edge 26a, 26b may vary. As shown in Figures 18(P)-18(T), the base end position P2 of the other side edge 27a, 27b is located midway along the upper edge of the hand hole, the angle θ2 of the other side edge 27a, 27b is an acute angle, and the base end position P1 and angle θ1 of the one side edge 26a, 26b may vary.

[0082] As shown in Figures 19(A) and (B), the second folded pieces 25a and 25b are formed in a triangular shape, and the tips of the second folded pieces 25a and 25b are in contact with the lower edge of the rounded square-shaped hand hole. The base end positions P1 and P2 may be changed when the base end position of one side edge 26a and 26b of the second folded pieces 25a and 25b is P1 and the base end position of the other side edge 27a and 27b of the second folded pieces 25a and 25b is P2. Also, the angles θ1 and θ2 may be changed when the angle of one side edge 26a and 26b with respect to the fold lines L10 and L11 is θ1 and the angle of the other side edge 27a and 27b with respect to the fold lines L10 and L11 is θ2.

[0083] For example, as shown in Figures 20(A) and 20(B), the base end position P2 of the other side edge 27a, 27b may be located at the other end of the upper edge of the hand hole, the angle θ2 of the other side edge 27a, 27b may be a right angle, and the base end position P1 and angle θ1 of the one side edge 26a, 26b may vary. As shown in Figures 20(C) to 20(E), the base end position P2 of the other side edge 27a, 27b may be located at the other end of the upper edge of the hand hole, the angle θ2 of the other side edge 27a, 27b may be an acute angle, and the base end position P1 and angle θ1 of the one side edge 26a, 26b may vary.

[0084] As shown in Figures 20(F)-20(I), the base end position P2 of the other side edges 27a and 27b may be located on the arc-shaped side edge of the hand hole, the angle θ2 of the other side edges 27a and 27b may be acute, and the base end position P1 and angle θ1 of the one side edge 26a and 26b may vary. As shown in Figures 20(J) and 20(K), the base end position P2 of the other side edges 27a and 27b may be located in the middle of the upper edge of the hand hole, the angle θ2 of the other side edges 27a and 27b may be right, and the base end position P1 and angle θ1 of the one side edge 26a and 26b may vary. As shown in Figures 20(L)-20(N), the base end position P2 of the other side edges 27a and 27b is located in the middle of the upper edge of the hand hole, the angle θ2 of the other side edges 27a and 27b is acute, and the base end position P1 and angle θ1 of the one side edge 26a and 26b may be varied.

[0085] As shown in Figures 21(A) and (B), the second folded pieces 25a and 25b are formed in a triangular shape, and the tips of the second folded pieces 25a and 25b are separated from the lower edge of the rounded square hand hole. The base end positions P1 and P2 may be changed when the base end position of one side edge 26a and 26b of the second folded pieces 25a and 25b is P1 and the base end position of the other side edge 27a and 27b of the second folded pieces 25a and 25b is P2. Also, the angles θ1 and θ2 may be changed when the angle of one side edge 26a and 26b with respect to the fold lines L10 and L11 is θ1 and the angle of the other side edge 27a and 27b with respect to the fold lines L10 and L11 is θ2.

[0086] For example, as shown in Figures 22(A) and 22(B), the area adjacent to the other side edges 27a and 27b may not be open, and the base end position P1 and angle θ1 of one side edge 26a and 26b may be changed. As shown in Figures 22(C) and 22(D), the base end position P2 of the other side edges 27a and 27b may be located at the other end of the upper edge of the hand hole, the angle θ2 of the other side edges 27a and 27b may be obtuse, and the base end position P1 and angle θ1 of one side edge 26a and 26b may be changed. As shown in Figures 22(E) and 22(F), the base end position P2 of the other side edges 27a and 27b may be located at the other end of the upper edge of the hand hole, the angle θ2 of the other side edges 27a and 27b may be right, and the base end position P1 and angle θ1 of one side edge 26a and 26b may be changed. As shown in Figures 22(G)-22(K), the base end position P2 of the other side edges 27a and 27b is located at the other end of the upper edge of the hand hole, the angle θ2 of the other side edges 27a and 27b is acute, and the base end position P1 and angle θ1 of the one side edge 26a and 26b may be changed.

[0087] As shown in Figures 22(L)-22(P), the base end position P2 of the other side edges 27a and 27b may be located on the arc-shaped side edge of the hand hole, the angle θ2 of the other side edges 27a and 27b may be acute, and the base end position P1 and angle θ1 of the one side edge 26a and 26b may vary. As shown in Figures 22(Q) and 22(R), the base end position P2 of the other side edges 27a and 27b may be located in the middle of the upper edge of the hand hole, the angle θ2 of the other side edges 27a and 27b may be obtuse, and the base end position P1 and angle θ1 of the one side edge 26a and 26b may vary. As shown in Figures 22(S) and 22(T), the base end position P2 of the other side edge 27a, 27b is located midway along the upper edge of the hand hole, the angle θ2 of the other side edge 27a, 27b is a right angle, and the base end position P1 and angle θ1 of the one side edge 26a, 26b may vary. As shown in Figures 22(U) to 22(X), the base end position P2 of the other side edge 27a, 27b is located midway along the upper edge of the hand hole, the angle θ2 of the other side edge 27a, 27b is an acute angle, and the base end position P1 and angle θ1 of the one side edge 26a, 26b may vary.

[0088] Furthermore, in the modified example of the second folded piece described above, the fold lines L10 and L11 are formed horizontally, but the fold lines L10 and L11 may also be inclined.

[0089] Although each embodiment and modification illustrates an example, it is sufficient that the inner flap is opened such that when the second folded piece is pressed into the first folded piece, the second folded piece folds back in the direction of the first folded piece.

[0090] Furthermore, while a wrap-around case is exemplified as the packaging box in each embodiment and each modification, any packaging box capable of forming hand holes with an outer flap and an inner flap is acceptable. For example, the packaging box may be a corrugated cardboard box of type A.

[0091] Furthermore, in each embodiment and each modification, a pair of second folded pieces are formed on a pair of inner flaps, but it is sufficient if the second folded piece is formed on at least one of the inner flaps. For example, in a packaging box in which short flaps are used as inner flaps, the second folded piece is formed on only one of the inner flaps. In this case, the portion adjacent to one side edge of the second folded piece may be cut out. The first folded piece does not press down on one side edge of the second folded piece. By preventing a pressing force from acting on the leading edge of one of the inner flaps, it is prevented that one of the inner flaps will fold in the middle and open sideways.

[0092] In each embodiment and each modification, the fold line may be formed by a creasing line. A creasing line refers to a fold line formed by pressing a corrugated cardboard sheet in a straight line from the liner side. The fold line may be formed by other fold lines such as perforations, lead lines, or half-cuts, as long as the corrugated cardboard sheet is bendable. A perforation line refers to a fold line formed by intermittently creating multiple cuts, a lead line refers to a fold line formed by alternating perforations and creasing lines, and a half-cut refers to a fold line in which a cut is made up to half the thickness of the corrugated cardboard sheet.

[0093] Furthermore, in each embodiment and each modification, the fold line of the first folded piece may be formed by a step created by flattening the outer flap. In this case, the region above the base end of the first folded piece (the region on the outer flap side) may be flattened, or the region below the base end of the first folded piece (the region on the first folded piece side) may be flattened. Similarly, the fold line of the second folded piece may be formed by a step created by flattening the inner flap. In this case, the region above the base end of the second folded piece (the region on the inner flap side) may be flattened, or the region below the base end of the second folded piece (the region on the second folded piece side) may be flattened. This allows the first and second folded pieces to be folded along the step created by the flattening.

[0094] Furthermore, while bottles are used as examples of products in each embodiment and each modification, the product is not limited to anything that can be contained in a packaging box.

[0095] Furthermore, in each embodiment and each modification, the packaging box is formed from a double-sided corrugated cardboard sheet, but the packaging box may also be formed from a single-sided corrugated cardboard sheet, a double-sided corrugated cardboard sheet, single sheet paper, cardboard, resin sheet, etc.

[0096] Furthermore, the shape of the hand holes in the outer and inner flaps is not limited to a rounded rectangle shape and may be modified as appropriate so as not to come into contact with the product inside the packaging box. Also, the shapes of the first and second folded flaps, openings, etc., are not particularly limited.

[0097] As described above, the first embodiment is a packaging box (1) in which a pair of inner flaps (14a, 14b) are folded inside an outer flap (15a), comprising a first handhole-shaped fold-back piece (21) formed on the outer flap and a second fold-back piece (25a) formed on at least one of the inner flaps, wherein the tip of at least one inner flap is one side edge (26a) of the second fold-back piece, the fold line (L10) of the second fold-back piece is positioned along the fold line (L9) of the first fold-back piece, and at least one of the inner flaps is opened such that when the second fold-back piece is pushed into the first fold-back piece, the second fold-back piece folds back in the direction of the fold of the first fold-back piece. In this configuration, when the second folded piece is pressed into the first folded piece, the first and second folded pieces fold back using the fold line as a starting point, with the first folded piece wrapping around the second folded piece. The pressing force acting on the second folded piece in the folding direction prevents unintended folding of at least one of the inner flaps, thus preventing the inner flap from opening sideways. The outer flap, inner flap, first folded piece, and second folded piece create a quadruple layer in the hand grip area of ​​the handhole, increasing rigidity and reducing strain on the hand.

[0098] In the second embodiment, the portion adjacent to the other side edge (27a) of the second folded piece is opened, and the tip (28a) of the second folded piece is separated from at least one inner flap. With this configuration, since the second folded piece and at least one inner flap are separated by the opening, the pressing force of the first folded piece is less likely to be transmitted to at least one inner flap via the second folded piece. When a pressing force is applied to the second folded piece in the folding direction, the folding of at least one inner flap is suppressed, preventing it from opening sideways.

[0099] In the third embodiment, the portion beyond the tip of the second folded piece is open, and the other side edge of the second folded piece is separated from at least one inner flap. With this configuration, when the first folded piece is folded partway, the second folded piece is pressed into the first folded piece. The pressing force acting on the second folded piece in the folding direction prevents at least one inner flap from folding in the middle and thus prevents it from opening sideways.

[0100] In the fourth embodiment, as in the first embodiment, an opening is provided at a location adjacent to the other side edge of the second folded piece and at a location beyond the tip of the second folded piece. With this configuration, since the second folded piece and at least one inner flap are separated by the opening, the pressing force of the first folded piece is less likely to be transmitted to the inner flap via the second folded piece. Also, when the first folded piece is folded partway back, the second folded piece is pressed against the first folded piece. The pressing force acting on the second folded piece in the folding direction suppresses the folding of at least one inner flap in the middle, preventing it from opening sideways.

[0101] The fifth embodiment is such that, in any one embodiment of the first to fourth embodiments, a portion adjacent to one side edge (26a) of the second folded piece is cut out. With this configuration, the one side edge of the second folded piece is not pressed in by the first folded piece. By preventing a pressing force from acting on the tip side of at least one of the inner flaps, it is prevented that at least one of the inner flaps will open sideways due to folding in the middle.

[0102] The sixth embodiment is one of the first to fourth embodiments, in which a pair of second folded pieces (26a, 26b) are formed on a pair of inner flaps. With this configuration, the folding of the pair of inner flaps in the middle is suppressed, preventing them from opening both sides.

[0103] The seventh aspect is a modification of the sixth aspect, in which the tips of a pair of inner flaps are notched, creating an opening between a pair of second folded pieces. With this configuration, the space between the pair of second folded pieces is not pressed in by the first folded piece. By preventing any pressing force from acting on the tip side of the pair of inner flaps, the pair of inner flaps are prevented from opening in half by folding in the middle.

[0104] The eighth aspect is one of the first to fifth aspects, in which the base ends of a pair of inner flaps are bonded to the outer flap. With this configuration, even though the base ends of a pair of inner flaps are bonded to the outer flap, the first folded piece can be pushed in to wrap around and fold back the pair of second folded pieces.

[0105] The ninth embodiment is a packaging box in which multiple products are packaged according to any one embodiment of the sixth to eighth embodiments, wherein a first folded flap and a pair of second folded flaps are positioned between adjacent products (bottles 32). With this configuration, the first folded flap and the pair of second folded flaps do not interfere with the products.

[0106] The tenth embodiment is one of the first to ninth embodiments in which the fold line of the second folded piece is formed by a step created by flattening at least one of the inner flaps. With this configuration, the second folded piece can be folded along the flattened step.

[0107] Although this embodiment has been described, other embodiments may include combinations of the above embodiments and modifications, either entirely or partially.

[0108] Furthermore, the technology of the present invention is not limited to the embodiments described above, and may be modified, substituted, or transformed in various ways without departing from the spirit of the technical idea. Moreover, if the technical idea can be realized in a different way by advances in the technology or by other derived technologies, it may be implemented by that method. Accordingly, the claims cover all embodiments that may fall within the scope of the technical idea. [Explanation of Symbols]

[0109] 1: Packaging box 14a, 14b: Inner flap 15a: Outer flap 21: First folded piece 25a, 25b: Second folded piece 26a, 26b: One side edge of the second folded piece 27a, 27b: Other side edge of the second folded piece 28a, 28b: Tip of the second folded piece 29a, 29b: Opening 30: hand hole 32: Bottle (product)

Claims

1. A packaging box (1) in which a pair of inner flaps (14a, 14b) are folded inside an outer flap (15a), The outer flap has a first folded-over piece (21) in the shape of a handhole, It comprises a second folded-over piece (25a) formed on at least one of the inner flaps, The second folded piece has one side edge (26a) of the tip of at least one of the inner flaps, The fold line (L10) of the second folded piece is located along the fold line (L9) of the first folded piece. A packaging box characterized in that at least one of the inner flaps is open such that when the second folded piece is pressed into the first folded piece, the second folded piece folds back in the direction of the first folded piece.

2. The packaging box according to claim 1, characterized in that an opening is made at the other side edge (27a) of the second folded piece, and the tip (28a) of the second folded piece is separated from at least one of the inner flaps.

3. The packaging box according to claim 1, characterized in that the portion beyond the tip of the second folded piece is open, and the other side edge of the second folded piece is separated from at least one of the inner flaps.

4. The packaging box according to claim 1, characterized in that an opening is provided at a location adjacent to the other side edge of the second folded piece and at a location beyond the tip of the second folded piece.

5. The packaging box according to any one of claims 1 to 4, characterized in that a portion adjacent to one side edge (26a) of the second folded piece is cut out.

6. The packaging box according to any one of claims 1 to 4, characterized in that a pair of second folded pieces (26a, 26b) are formed on the pair of inner flaps.

7. The packaging box according to claim 6, characterized in that the tips of the pair of inner flaps are cut out and an opening is formed between the pair of second folded pieces.

8. The packaging box according to claim 1, characterized in that the base ends of the pair of inner flaps are adhered to the outer flap.

9. A packaging box containing multiple products, The packaging box according to claim 6, characterized in that the first folded piece and the pair of second folded pieces are positioned between adjacent products (32).

10. The packaging box according to claim 1, characterized in that the fold line of the second folded piece is formed by a step created by flattening at least one of the inner flaps.

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