Packaging box

Abstract

To provide a packaging box capable of reducing the number of places where a step is formed even when the tip sides of a pair of flaps are overlapped with each other.SOLUTION: Packaging box 1 includes a cylindrical body 1T and a pair of upper outer flaps 15 that close the top opening of the cylindrical body 1T with their tip ends overlapping each other. In one upper outer flap 15A, an inner layer piece 20 and an outer layer piece 21 are partitioned by a cut line 22 extending from the tip to the base end, and a push-in hole 30 is formed in the other upper outer flap 15B. When closing the top opening of the cylindrical body 1T, the tip side of the other upper outer flap 15B is inserted into the cut line 22 of one upper outer flap 15A, the inner layer piece 20 is placed below the other upper outer flap 15B, and the outer layer piece 21 is placed above the other upper outer flap 15B, and then pushed into the push-in hole 30 so as to be flush with the surface of the other upper outer flap 15B.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] A paper packaging box is known in which the top opening of a rectangular prism-shaped cylindrical body is sealed by folding two inner flaps and two outer flaps together (Patent Document 1). The two outer flaps overlap each other except for their base ends to close the top opening of the cylindrical body. A label (or adhesive tape) is then affixed across the tip of the upper outer flap and the lower outer flap. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-79159 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned paper packaging box, the upper outer flap is simply placed on the lower outer flap, so that a step corresponding to the thickness of the upper outer flap is formed over the entire length. Since the label or the like is affixed so as to straddle the step, the label or the like is in a floating state due to the step. As a result, the affixing area (adhesion area) of the label or the like on the surface of the outer flap is reduced, and the label or the like is easily peeled off.

[0005] In consideration of the above circumstances, the present invention provides a packaging box that can reduce the number of locations where steps are formed even when the tip sides of a pair of flaps are overlapped with each other. [Means for solving the problem]

[0006] The packaging box of the present invention comprises a cylindrical body formed into a cylindrical shape by a plurality of side walls, and a pair of flaps connected to the upper ends of a pair of opposing side walls across the internal space of the cylindrical body and closing the top opening of the cylindrical body with their tip ends overlapping each other, one of the flap is partitioned into at least one inner layer piece and at least one outer layer piece by at least one cut line extending from the tip to the base end, and the other flap has at least one push hole formed therein, and when the top opening of the cylindrical body is closed, the tip side of the other flap is inserted into the cut line of one of the flap, the inner layer piece is positioned below the other flap, and the outer layer piece is positioned above the other flap, and then pushed into the push hole so as to form the same surface as the surface of the other flap.

[0007] In this case, it is preferable that one of the flaps has an inclined fold line formed thereon, which is inclined from the end of the incision direction of the incision line toward the boundary line with the side wall so as to move away from the inner layer piece.

[0008] In this case, a pair of the cut lines are cut into one of the flaps at a horizontal interval, the outer layer piece is provided between the pair of cut lines, a pair of the inner layer pieces are provided adjacent to both sides of the outer layer piece in the horizontal direction via the pair of cut lines, and one of the flaps is formed with a pair of inclined fold lines that incline toward each other from the ends of the pair of cut lines in the cutting direction toward the boundary line with the side wall, and an auxiliary fold line is formed from the tip of the outer layer piece toward the boundary line so as to horizontally divide one of the flap in two.

[0009] In this case, a pair of outer layer convex portions that protrude relatively are formed at the tip side of the outer layer piece by recessing the central portion in the horizontal direction, and a pair of pushing holes are formed in the other flap for pushing in the pair of outer layer convex portions.

[0010] In another case, one of the flaps may have a second inclined fold line formed therein, inclined from an end of the incision direction of the incision line toward a boundary line with the side wall and away from the outer layer piece.

[0011] In this case, it is preferable that the tip of the outer layer piece is shifted toward the base end side relative to the tip of the inner layer piece. Effect of the Invention

[0012] According to the present invention, even when the tip sides of a pair of flaps are overlapped with each other, the number of locations where steps are formed can be reduced. [Brief description of the drawings]

[0013] [Figure 1] 1 is a perspective view showing a packaging box according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view showing a blank for a packaging box according to one embodiment of the present invention. [Diagram 3] 1 is a perspective view showing a state in which a pair of upper inner flaps of a packaging box according to one embodiment of the present invention are closed. [Figure 4] 1 is a perspective view showing a process of closing a pair of upper outer flaps of a packaging box according to one embodiment of the present invention. FIG. [Diagram 5] 1 is a perspective view showing a state in which a pair of upper outer flaps of a packaging box according to one embodiment of the present invention are closed (immediately before being temporarily fastened). [Figure 6] FIG. 2 is a plan view showing a blank for a packaging box according to a first modified example of an embodiment of the present invention. [Figure 7] FIG. 11 is a plan view showing a blank for a packaging box according to a second modified example of one embodiment of the present invention. [Figure 8] FIG. 11 is a perspective view showing a packaging box according to a second modified example of one embodiment of the present invention. [Figure 9] FIG. 11 is a perspective view showing a packaging box according to a third modified example of one embodiment of the present invention. [Figure 10] FIG. 11 is a perspective view showing a packaging box according to a fourth modified example of one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the attached drawings. Note that Fr, Rr, L, R, U, and D shown in the drawings indicate front, rear, left, right, top, and bottom. The front-rear direction, left-right direction, and top-bottom direction are mutually perpendicular. Terms indicating directions and positions are used in this specification, but these terms are used for convenience of explanation and do not limit the technical scope of the present invention. In addition, the terms indicating directions and positions are based on the directions and positions in the assembled state of the packaging box.

[0015] A packaging box 1 according to one embodiment will be described with reference to Figures 1 and 2. Figure 1 is a perspective view showing the packaging box 1. Figure 2 is a plan view showing a blank 1A of the packaging box 1.

[0016] As shown in Fig. 1, the packaging box 1 is a cardboard box formed into a generally rectangular parallelepiped shape as a whole. The packaging box 1 includes a cylindrical body 1T formed into a generally rectangular cylindrical shape by a number of side walls 10, 11, and a number of flaps 12-15 that close both end faces in the upper and lower directions of the cylindrical body 1T. As will be described in detail later, a pair of upper outer flaps 15 that form the top surface of the packaging box 1 are fixed by attaching a label 90 such as a delivery slip.

[0017] The packaging box 1 is assembled from a blank 1A shown in Fig. 2. The blank 1A is formed by punching out a single piece of cardboard sheet made of paper using a die or the like. The cardboard sheet is, for example, a double-sided cardboard sheet with liners attached to the front and back of a corrugated core 9A. Note that Fig. 2 shows the front (outer) side of the packaging box 1. In this specification, the direction parallel to the core 9A of the cardboard sheet is referred to as the "corrugation direction", and the direction perpendicular to the corrugation direction is referred to as the "flow direction". In the drawings, "X" indicates the "corrugation direction" and "Y" indicates the "flow direction".

[0018] [blank] 2, the blank 1A includes a pair of first side walls 10, a pair of second side walls 11, a pair of lower inner flaps 12, a pair of lower outer flaps 13, a pair of upper inner flaps 14, and a pair of upper outer flaps 15. Since the pair of portions have substantially the same shape, hereinafter, unless otherwise specified, only one portion will be described.

[0019] <First side wall, second side wall> A pair of first side walls 10 and a pair of second side walls 11 are alternately connected in the flow direction via a first folding line L1. The first side walls 10 and the second side walls 11 are formed in a substantially rectangular shape. In detail, the first side walls 10 are formed in a substantially rectangular shape that is shorter in the flow direction than the second side walls 11. A joint piece 16 is connected to one end of the second side walls 11 in the flow direction via the first folding line L1. The pair of first side walls 10 and the pair of second side walls 11 form a substantially square cylindrical body 1T.

[0020] <Lower inner flap, lower outer flap> The lower inner flap 12 is connected to one end (lower end) in the step direction of the first side wall 10 via the second fold line L2. The lower outer flap 13 is connected to one end (lower end) in the step direction of the second side wall 11 via the second fold line L2. The lower inner flap 12 and the lower outer flap 13 are each formed in a substantially rectangular shape, and their dimension in the step direction (extension dimension) is approximately half the dimension in the flow direction of the first side wall 10. The pair of lower inner flaps 12 and the pair of lower outer flaps 13 are folded in this order to close the lower opening of the cylindrical body 1T. With the lower opening of the cylindrical body 1T closed, the pair of lower outer flaps 13 butt their tips against each other.

[0021] <Upper inner flap, upper outer flap> The upper inner flap 14 is connected to the other end (upper end) of the first side wall 10 in the step direction via the third fold line L3. The upper outer flap 15 is connected to the other end (upper end) of the second side wall 11 in the step direction via the third fold line L3. The upper inner flap 14 and the upper outer flap 15 are each formed in a substantially rectangular shape, and their dimension in the step direction (extension dimension) is longer than half the dimension in the flow direction of the first side wall 10 and shorter than the said dimension (overall). The pair of upper inner flaps 14 and the pair of upper outer flaps 15 are folded in this order to close the upper opening 1U of the cylindrical body 1T. In a state in which the upper opening 1U of the cylindrical body 1T is closed, the pair of upper outer flaps 15 overlap each other at their tip sides.

[0022] The first to third fold lines L1 to L3 are general-purpose lines formed by flattening the cardboard sheet in the thickness direction from the back surface (inner surface), but are not limited thereto. For example, any structure for folding the cardboard sheet in the desired direction may be used, such as perforations or lead lines formed by perforations on general-purpose lines.

[0023] The above-mentioned blank 1A is folded twice (initial state) to form a packaging box 1 (not shown). Specifically, the first side wall 10 and the second side wall 11 located on both outer sides in the flow direction of the blank 1A are folded back inward along the first folding line L1, and the joint piece 16 is adhered to the back surface of the first side wall 10 on the opposite side.

[0024] [Temporary fastening structure] As shown in FIG. 2, the pair of upper outer flaps 15 are provided with a temporary fastening structure 17 that temporarily holds the upper opening 1U of the cylinder 1T in a closed state. The temporary fastening structure 17 has a pair of inner layer pieces 20, an outer layer piece 21, and a pair of push-in holes 30. For example, the inner layer piece 20 and the outer layer piece 21 are formed in the upper outer flap 15 on one side of the flow direction (the side of the transition piece 16), and the push-in hole 30 is formed in the upper outer flap 15 on the other side of the flow direction (between the pair of upper inner flaps 14). In this specification, for the sake of convenience of explanation, when one upper outer flap 15 and the other upper outer flap 15 are to be distinguished from each other, the reference character "A" is added to one upper outer flap 15, and the reference character "B" is added to the other upper outer flap 15.

[0025] <Inner layer piece, outer layer piece> The pair of inner layer pieces 20 and the outer layer piece 21 are partitioned in one upper outer flap 15A by a pair of cut lines 22. The pair of cut lines 22 extend from the tip of the upper outer flap 15A toward the base end in a manner substantially parallel to the step direction (first fold line L1). The pair of cut lines 22 are formed by cutting the tip side of the upper outer flap 15A in the thickness direction, and are formed to be substantially the same length. In detail, the cut lines 22 are cut from the tip of the upper outer flap 15A to a position that is approximately 1 / 3 of the extension dimension. The pair of cut lines 22 are cut at positions that are spaced apart from each other in the flow direction (horizontal direction) and are shifted toward the center by the same distance from both ends in the flow direction of the upper outer flap 15A. The pair of cut lines 22 may be formed to be different lengths from each other, and may not be parallel to each other (not shown).

[0026] The outer layer piece 21 is provided between a pair of cut lines 22, and the pair of inner layer pieces 20 are provided adjacent to both sides of the outer layer piece 21 in the flow direction (horizontal direction) via the pair of cut lines 22. In other words, the pair of inner layer pieces 20 and the outer layer piece 21 occupy about 1 / 3 of the range of the tip side in the step direction of the upper outer flap 15A. An outer layer recess 23 is recessed at the tip side in the step direction of the outer layer piece 21 and at the center in the flow direction. In this way, by recessing the center in the flow direction (horizontal direction), a pair of outer layer protrusions 24 that protrude relatively are formed at the tip side of the outer layer piece 21. The outer layer recess 23 is a substantially rectangular recess, and the outer layer protrusion 24 is a substantially rectangular protrusion.

[0027] Additionally, the outer layer piece 21 is shorter in the step direction than the inner layer piece 20, and the tip of the outer layer piece 21 is shifted toward the base end side from the tip of the inner layer piece 20. In detail, the tip of the outer layer convex portion 24 is recessed by one step from the tip of the inner layer piece 20, and the tip edge of the outer layer concave portion 23 is recessed by one step from the tip of the outer layer convex portion 24.

[0028] (slanted fold line) The upper outer flap 15A is formed with a pair of inclined fold lines L4 that are inclined from the end of the pair of incision lines 22 in the incision direction (base end in the row direction) toward the boundary line with the second side wall 11 (third fold line L3) so as to approach each other. Each inclined fold line L4 is inclined from the end of the incision line 22 toward the base end so as to move away from the inner layer piece 20, and the angle with the third fold line L3 is set to about 45 degrees. That is, the pair of inclined fold lines L4 is formed in a substantially V-shape bent at a right angle. Note that the pair of inclined fold lines L4 intersect the third fold line L3, but this is not limited thereto, and the base end of the pair of inclined fold lines L4 may be slightly away from the third fold line L3. The inclination angle of the inclined fold line L4 is not limited to 45 degrees and may be changed as appropriate. The inclination angles of the pair of inclined fold lines L4 do not need to be the same, and may be different from each other (not shown). Moreover, the inclined folded line L4 is not limited to a straight line, and may be a slightly curved line (not shown).

[0029] (auxiliary fold line) In addition, the upper outer flap 15A is formed with an auxiliary fold line L5 from the tip of the outer layer piece 21 toward the third fold line L3 (boundary line) to bisect the outer layer piece 21 in the flow direction (horizontal direction). The auxiliary fold line L5 extends approximately parallel to the row direction (slit line 22) from the tip edge of the outer layer recess 23 to the intersection of the pair of inclined fold lines L4. In other words, the auxiliary fold line L5 is formed in the approximate center of the flow direction of the upper outer flap 15A including the outer layer piece 21, and is a line that bisects the upper outer flap 15A in the flow direction. The pair of inclined fold lines L4 described above are formed to be symmetrical with respect to the auxiliary fold line L5.

[0030] Although the inclined fold line L4 and the auxiliary fold line L5 are lead lines, they are not limited to this and may be any structure for folding the cardboard sheet in a desired direction.

[0031] <Push-in hole> A pair of press holes 30 are formed on the tip side in the step direction of the other upper outer flap 15B. The pair of press holes 30 are formed at positions offset from both ends of the upper outer flap 15B in the step direction by the same distance toward the center with a gap between them in the flow direction (horizontal direction). The gap between the pair of press holes 30 is approximately the same as the gap between the pair of outer layer protrusions 24 of the outer layer piece 21. The press holes 30 are formed in an area surrounded by a cut line 31 cut into the tip side of the upper outer flap 15B. The cut line 31 is formed by cutting the upper outer flap 15B in the thickness direction, and is formed in a substantially U-shape (substantially C-shape) with the tip side in the step direction open. The press hole 30 is opened by pressing down the press piece 32 partitioned by the cut line 31. The press piece 32 (press hole 30) is formed in a substantially rectangular shape that is approximately the same shape as the outer layer protrusion 24. In addition, auxiliary cuts extending slightly radially are cut at the two corners of the cut line 31 to make it easier to push down the push-in piece 32.

[0032] [Assembly and sealing of packaging boxes] Next, the procedure for assembling and sealing the packaging box 1 will be described with reference to Fig. 1 and Fig. 3 to Fig. 5. Fig. 3 is a perspective view showing a pair of upper inner flaps 14 in a closed state. Fig. 4 is a perspective view showing a process of closing a pair of upper outer flaps 15. Fig. 5 is a perspective view showing a pair of upper outer flaps 15 in a closed state (just before temporary fastening). Here, as an example, a case where a worker manually assembles and seals the packaging box 1 will be described. In this specification, folding a cardboard sheet with the back surface facing inward is referred to as "forward folding", and folding a cardboard sheet with the front surface facing inward is referred to as "reverse folding".

[0033] The worker lifts up the double-folded packaging box 1 to form a substantially rectangular cylindrical body 1T (see FIG. 3). A pair of first side walls 10 face each other in the left-right direction with the internal space of the cylindrical body 1T between them, and a pair of second side walls 11 face each other in the front-rear direction with the internal space of the cylindrical body 1T between them.

[0034] Next, the worker folds the pair of lower inner flaps 12 inward along the second fold line L2, and then folds the pair of lower outer flaps 13 inward along the second fold line L2. The tips of the pair of lower inner flaps 12 are separated from each other, and the tips of the pair of lower outer flaps 13 are butted against each other. The worker applies adhesive tape T along the butted portion of the pair of lower outer flaps 13 (see FIG. 3, etc.). As a result, the lower opening of the cylindrical body 1T is closed, and the bottom surface of the packaging box 1 is formed. Note that the method of fixing the pair of lower outer flaps 13 is not limited to the adhesive tape T, and for example, the pair of lower outer flaps 13 may be fixed to the pair of lower inner flaps 12 via an adhesive.

[0035] Next, the worker places a product (not shown) in the internal space through the top opening 1U of the cylindrical body 1T, and closes the top opening 1U of the cylindrical body 1T with the top inner flap 14 and the top outer flap 15. Specifically, the worker folds the pair of top inner flaps 14 inward along the third folding line L3 (see FIG. 3), and then folds the pair of top outer flaps 15 inward along the third folding line L3 (see FIG. 4). Since the extension dimension of each of the top outer flaps 15 is longer than half the front-to-back width (horizontal width) of the first side wall 10, when the top opening 1U of the cylindrical body 1T is closed (when the top surface of the packaging box 1 is formed), the pair of top outer flaps 15 overlap each other at their tip ends. Then, a step is formed on the top surface of the packaging box 1 by the thickness of the top outer flap 15. The step is formed on the top surface of the packaging box 1 over the entire left-right direction. If the label 90 is affixed so as to straddle the step in order to fix the pair of upper outer flaps 15, the label 90 will be in a floating state at the step, reducing the affixing area (contact area) of the label 90 relative to the surface of the upper outer flap 15 and making the label 90 more likely to peel off. Therefore, in the packaging box 1 according to this embodiment, the temporary fastening structure 17 reduces the number of locations where steps are formed even when the leading ends of the pair of upper outer flaps 15 are overlapped with each other.

[0036] For example, an operator places a hand (fingers) on the leading edge of the outer layer recess 23 of the outer layer piece 21 and pulls up the outer layer piece 21, thereby bending the left-right middle portion of the upper outer flap 15A including the outer layer piece 21 as shown in Fig. 4. The middle portion of the upper outer flap 15A including the outer layer piece 21 is folded backward along a pair of inclined fold lines L4 and forward along auxiliary fold line L5. By pulling up the outer layer piece 21, the pair of inner layer pieces 20 move relatively downward, and gaps are formed along the pair of cut lines 22.

[0037] The worker further folds (bends) the pair of upper outer flaps 15 inward while contacting the tips of the pair of inner layer pieces 20 with the back surface (inner surface) of the tip side of the other upper outer flap 15B. Because the inner layer piece 20 protrudes further toward the tip side than the outer layer piece 21, the tip portion of the upper outer flap 15B contacts the inner layer piece 20 without interfering with the outer layer piece 21. Then, the tip portions of the pair of inner layer pieces 20 move toward the base end side (rearward) while contacting the back surface of the upper outer flap 15B, and the upper outer flap 15B is inserted into the gap along the pair of cut lines 22 while contacting its tip with the back surface of the outer layer piece 21.

[0038] As shown in FIG. 5, when the pair of upper outer flaps 15 are folded (bent) until they are substantially horizontal, the tip side of the upper outer flap 15B is inserted into the pair of cut lines 22, the pair of inner layer pieces 20 are disposed below the upper outer flap 15B, and the outer layer piece 21 is disposed above the upper outer flap 15B. In other words, the tip side of the upper outer flap 15B is bitten into the pair of cut lines 22 and sandwiched between the pair of inner layer pieces 20 and the outer layer piece 21. In addition, both sides of the upper outer flap 15B in the left-right direction are stacked on the pair of inner layer pieces 20, and the outer layer piece 21 is stacked on the middle part of the upper outer flap 15B in the left-right direction. In detail, the pair of outer layer protrusions 24 of the outer layer piece 21 are stacked on the pair of push-in holes 30 (pushing pieces 32) formed in the upper outer flap 15B. The tip edge of the outer layer recess 23 of the outer layer piece 21 is laminated onto the tip portion of the upper outer flap 15B between the pair of push-in holes 30.

[0039] Then, the worker pushes down the pair of outer layer protrusions 24. The push-in pieces 32 of the upper outer flap 15B are pushed down together with the outer layer protrusions 24 to open the push-in holes 30, and as shown in FIG. 1, the outer layer protrusions 24 are pushed (fitted) into the push-in holes 30. The (surface of) the outer layer protrusions 24 pushed into the push-in holes 30 is flush with the surface of the upper outer flap 15B. The tip of the outer layer protrusions 24 is caught on the edge of the push-in holes 30 (the cut line 31), so the outer layer protrusions 24 are held in a position where they are flush with the surface of the upper outer flap 15B. To be precise, the outer layer piece 21 has the outer layer protrusions 24 fitted into the push-in holes 30 by climbing over the upper outer flap 15B, which is on the tip side of the push-in holes 30, so that the outer layer piece 21 including the outer layer protrusions 24 is slightly curved in an arch shape. That is, the (surface of) the outer layer protrusion 24 is "flush" with the surface of the upper outer flap 15B does not mean that they are exactly flush, but rather that a slight difference in level is permitted. Also, the entire surface of the outer layer protrusion 24 (outer layer piece 21) does not need to be flush with the surface of the upper outer flap 15B, but it is sufficient that at least the tip of the outer layer protrusion 24 (outer layer piece 21) and the edge of the push-in hole 30 are flush with each other.

[0040] As a result of the above, the upper opening 1U of the cylindrical body 1T is closed, forming the top surface of the packaging box 1 (see FIG. 1).

[0041] The pair of upper outer flaps 15 are only temporarily held in position (temporarily fastened) by the temporary fastening structure 17, and are not completely fixed. As shown in FIG. 1, an operator attaches a label 90 so as to straddle the pair of upper outer flaps 15, thereby fixing the pair of upper outer flaps 15. For example, the entire back surface of the label 90 is made an adhesive surface to which an adhesive (adhesive) is applied. The position of attachment of the label 90 is not particularly limited, but it is preferable that the label 90 is attached to an area including the outer layer protrusion 24 (outer layer piece 21) that fits into the push-in hole 30 to eliminate (reduce) the step. In FIG. 1, as an example, the label 90 is attached so as to cover the outer layer piece 21 and the push-in hole 30. Note that the pair of upper outer flaps 15 may be fixed by a sheet with an adhesive back surface, such as a sticker or a normal adhesive tape, instead of the label 90 (not shown).

[0042] As a result of the above, the pair of upper outer flaps 15 are fixed and the packaging box 1 is sealed (see FIG. 1).

[0043] In the packaging box 1 according to the present embodiment described above, when the top opening 1U of the cylinder 1T is closed, the tip side of the other upper outer flap 15B is inserted into the cut line 22 of one upper outer flap 15A, the inner layer piece 20 is arranged below the upper outer flap 15B, and the outer layer piece 21 is arranged above the upper outer flap 15B, and then the inner layer piece 20 is pushed into the push hole 30 so as to be flush with the surface of the upper outer flap 15B (see FIG. 1). According to this configuration, by pushing the outer layer piece 21 into the push hole 30, it is possible to eliminate (reduce) the step between the tip of the outer layer piece 21 (outer layer protrusion 24) and the other upper outer flap 15B. This makes it possible to reduce the number of places where the step is formed, compared to when the tip sides of the pair of upper outer flaps 15 are simply overlapped with each other. As a result, for example, the affixing area (adhesion area) of the label 90 on the surface of the pair of upper outer flaps 15 can be increased, and peeling of the label 90 can be suppressed.

[0044] In the packaging box 1 according to the present embodiment, a pair of inclined fold lines L4 are formed in a substantially V-shape in one of the upper outer flaps 15A from the ends of the pair of cut lines 22 toward the second side wall 11 (the third fold line L3), and the auxiliary fold line L5 is formed to horizontally bisect the outer layer piece 21. With this configuration, by lifting the outer layer piece 21, the upper outer flap 15A including the outer layer piece 21 can be folded in reverse at the pair of inclined fold lines L4 while being folded forward at the auxiliary fold line L5 (see FIG. 4). As a result, the upper outer flap 15A including the outer layer piece 21 can be shifted upward while being bent relative to the inner layer piece 20, and a gap can be opened along the cut line 22. As a result, it becomes easier to insert the tip of the upper outer flap 15B along the cut line 22 (gap), and as the upper outer flap 15B is inserted, the inner layer piece 20 can naturally slide under the upper outer flap 15B, and the outer layer piece 21 can be overlapped on the upper side of the upper outer flap 15B.

[0045] Furthermore, according to the packaging box 1 of this embodiment, the pair of outer layer protrusions 24 protruding from the tip side of the outer layer piece 21 fit into the pair of push-in holes 30, so the force for temporarily fastening the tips of the pair of upper outer flaps 15 together can be improved compared to the case where only one outer layer piece 21 is fitted into the push-in hole 30. This makes it possible to properly maintain the state in which the tips of the pair of upper outer flaps 15 are temporarily fastened together.

[0046] Furthermore, according to the packaging box 1 of this embodiment, the tip of the outer layer piece 21 is offset toward the second side wall 11 relative to the tip of the inner layer piece 20, so that when the pair of upper outer flaps 15 are closed, the tip of the other upper outer flap 15B is less likely to interfere with the tip of the outer layer piece 21. This makes it possible to insert the tip of the upper outer flap 15B into the cut line 22 while being guided by the tip (upper surface) of the inner layer piece 20. In other words, it is possible to make it easier for the tip of the inner layer piece 20 to slide under the upper outer flap 15B.

[0047] [First Modification] In the packaging box 1 according to the present embodiment, the inclined fold line L4 is inclined from the end of the cut line 22 toward the third fold line L3 so as to move away from the inner layer piece 20 in order to bend the upper outer flap 15A including the outer layer piece 21 upward, but the present invention is not limited thereto. As shown in FIG. 6, a second inclined fold line L6 (e.g., a lead crease) inclined in the opposite direction to the inclined fold line L4 may be formed as the packaging box 2 (blank 2A) according to the first modified example. The second inclined fold line L6 is inclined from the end of the cut line 22 toward the third fold line L3 so as to move away from the outer layer piece 21. According to this configuration, the upper outer flap 15A including the inner layer piece 20 is folded downward along the second inclined fold line L6, so that the outer layer piece 21 moves relatively upward and a gap can be formed along the cut line 22. As a result, the tip of the upper outer flap 15B can be easily inserted along the cut line 22, and other effects similar to those of the packaging box 1 according to the present embodiment described above can be obtained.

[0048] [Second modified example] In addition, in the packaging boxes 1 and 2 according to the present embodiment (including the first modification), one outer layer piece 21 is provided between a pair of inner layer pieces 20, but the present invention is not limited thereto. As shown in Figs. 7 and 8, the outer layer piece 21 and the pair of inner layer pieces 20 may be replaced with each other to provide one inner layer piece 20 between the pair of outer layer pieces 21 as a packaging box 3 (blank 3A) according to the second modification. In the packaging box 3 (blank 3A) according to the second modification, the outer layer recess 23, the outer layer protrusion 24, and the auxiliary fold line L5 are omitted from the upper outer flap 15A. In addition, the upper outer flap 15A is formed with a pair of inclined fold lines L4 that are inclined from the ends of the pair of cut lines 22 toward the third fold line L3 so as to move away from each other. That is, the pair of inclined fold lines L4 are formed in a substantially V-shape. In addition, a pair of cut lines 31 are formed in a substantially L-shape on both sides of the upper outer flap 15B except for the middle part in the flow direction (horizontal direction), and the pair of cut lines 31 define a push-in hole 30 (pushing piece 32). Both corners on the tip side of the upper outer flap 15B are cut out in a substantially rectangular shape. The pair of cut lines 31 extend to both ends (cut-out parts) of the upper outer flap 15B in the flow direction. Even with this configuration, it is possible to obtain the same effect as the packaging box 1 according to the above-mentioned embodiment, such as reducing the number of places where a step is formed even when the tip sides of the pair of upper outer flaps 15 are overlapped with each other. Note that the feature (second inclined fold line L6) of the packaging box 2 (blank 2A) according to the first modified example described above may be applied to the packaging box 3 (blank 3A) according to the second modified example (not shown). That is, a pair of inclined fold lines L4 and auxiliary fold lines L5 (see FIG. 2, etc.) of the packaging box 1 (blank 1A) may be formed in the middle of the upper outer flap 15B corresponding to the inner layer piece 20 shown in FIG. 7, and the inner layer piece 20 may be bent downward. In this case, the pair of inclined fold lines L4 function as a pair of second inclined fold lines L6.

[0049] [Other variations] In addition, in the packaging boxes 1 and 2 according to the present embodiment (including the first modified example), a pair of cut lines 22 are made in the upper outer flap 15A to separate a pair of inner layer pieces 20 and one outer layer piece 21, and in the packaging box 3 according to the second modified example, a pair of cut lines 22 are made in the upper outer flap 15A to separate one inner layer piece 20 and a pair of outer layer pieces 21, but the present invention is not limited to this. In one upper outer flap 15A, at least one inner layer piece 20 and at least one outer layer piece 21 may be separated by at least one cut line 22. For example, as shown in FIG. 9, in the upper outer flap 15A, three inner layer pieces 20 and two outer layer pieces 21 may be separated by four (two pairs) cut lines 22 (packaging box 4 according to the third modified example). In addition, as shown in FIG. 10, the upper outer flap 15A may be partitioned into one inner layer piece 20 and one outer layer piece 21 by one cut line 22 (packaging box 5 according to the fourth modified example). In addition, it is preferable that a push-in hole 30 (cut line 31, push-in piece 32) is formed in the other upper outer flap 15B so as to correspond to the number and shape of the outer layer pieces 21 provided in one upper outer flap 15A. In addition, in the packaging box 4 according to the third modified example, the feature (second inclined fold line L6) of the packaging box 2 according to the first modified example described above is applied, but this is not limited thereto, and the inclined fold line L4 of the packaging box 1 according to the present embodiment described above may be applied (not shown). In addition, in the packaging box 5 according to the fourth modified example, the inclined fold line L4 of the packaging box 1 according to the present embodiment described above is applied, but this is not limited thereto, and the feature (second inclined fold line L6) of the packaging box 2 according to the first modified example described above may be applied (not shown).

[0050] In addition, in the packaging boxes 1 and 2 according to the present embodiment (including the first modified example), the outer layer recess 23 and the pair of outer layer protrusions 24 are formed on the tip side of the outer layer piece 21, but this is not limited thereto, and the outer layer recess 23 and the pair of outer layer protrusions 24 may be omitted (not shown). In this case, the upper outer flap 15B is formed with a push-in hole 30 (score line 31, push-in piece 32) corresponding to the tip of the outer layer piece 21, and the tip of the outer layer piece 21 is pushed into the push-in hole 30 (not shown). In addition, the outer layer recess 23 is a substantially rectangular recess, and the outer layer protrusion 24 is a substantially rectangular protrusion, but this is not limited thereto, and the outer layer recess 23 and the outer layer protrusion 24 may be formed, for example, in a substantially semicircular (semi-elliptical) shape (not shown). Similarly, the inner layer piece 20 may also be formed, for example, in a substantially semicircular (semi-elliptical) shape (not shown).

[0051] In addition, in the packaging box 1 according to the present embodiment, the auxiliary fold line L5 is formed at approximately the center in the left-right direction of the upper outer flap 15A, but this is not limited thereto, and the auxiliary fold line L5 may be formed at a position shifted from the center in the left-right direction of the upper outer flap 15A, or the auxiliary fold line L5 may be omitted (not shown). In addition, the auxiliary fold line L5 is not limited to one, and may be formed multiple times between a pair of oblique fold lines L4 (not shown). In addition, in the packaging boxes 1 to 4 according to the present embodiment (including the first to fourth modified examples, the same applies below), the oblique fold line L4 or the second oblique fold line L6 is formed, but this is not limited thereto, and the oblique fold line L4 or the second oblique fold line L6 may be omitted (not shown).

[0052] In addition, in the packaging boxes 1 to 4 according to the present embodiment, the push-in holes 30 are formed by pushing in the push-in pieces 32 defined by the score lines 31, but the present invention is not limited to this. For example, the push-in holes 30 may be openings formed in the upper outer flap 15B (not shown).

[0053] In addition, in the packaging boxes 1 to 4 according to this embodiment, in order to reduce the step at the overlapping portion of the pair of upper outer flaps 15, the core 9A on the tip side of the pair of upper outer flaps 15 may be crushed (so-called step crushing processing (not shown)).

[0054] In addition, in the packaging boxes 1 to 4 according to the present embodiment, the pair of lower inner flaps 12 and the pair of lower outer flaps 13 are sequentially folded to close the bottom opening of the cylindrical body 1T, but the present invention is not limited to this. The bottom of the packaging boxes 1 to 4 may be, for example, a one-touch bottom that is automatically formed by deforming the cylindrical body 1T into a square cylindrical shape, or may be a so-called bottom (not shown). In addition, the packaging boxes 1 to 4 according to the present embodiment are cardboard boxes similar to the A-type, but the present invention is not limited to this. The features of the packaging boxes 1 to 4 according to the present embodiment (such as the temporary fastening structure 17) can be applied to boxes having flaps that close the opening of the cylindrical body formed in a cylindrical shape. In addition, the cylindrical body is not limited to a square cylindrical shape (rectangular parallelepiped shape), and may be, for example, formed into a substantially octagonal prism shape by obliquely chamfering the corners (not shown).

[0055] In addition, although the packaging boxes 1 to 4 according to the present embodiment are formed from double-sided corrugated cardboard sheets made of paper, the present invention is not limited to this. The packaging boxes 1 to 4 may be formed from single-sided corrugated cardboard, double-sided corrugated cardboard, triple-double-sided corrugated cardboard, etc., and may be formed from cardboard or a resin plate (sheet) or the like. In addition, the dimensions (width, depth, height) and shape of each part of the packaging box 1, the thickness of the sheet, the direction in which the core 9A extends, etc. may be freely changed.

[0056] The above embodiment is merely an example of the packaging box of the present invention, and the technical scope of the present invention is not limited to the above embodiment. The present invention may be modified, substituted, or altered in various ways without departing from the spirit of the technical idea, and the claims include all embodiments that may be included within the scope of the technical idea. [Explanation of symbols]

[0057] 1 packaging box 1T cylinder 1U top opening 10 First side wall (side wall) 11 Second side wall (side wall) 15 Upper outer flap 20 Inner layer piece 21 Outer layer piece 22 Cutting line 30 Press-in hole L3 Third bending line (boundary line) L4 Inclined broken line L5 Auxiliary broken line 24 Outer layer convex part L6 Second inclined broken line

Claims

1. A cylindrical body (1T) formed into a cylindrical shape by a plurality of side walls (10, 11); a pair of flaps (15) connected to upper ends of the pair of side walls (11) facing each other across the internal space of the cylindrical body, and closing an upper opening (1U) of the cylindrical body when their tip ends are overlapped with each other; One of the flaps (15A) is partitioned into at least one inner layer piece (20) and at least one outer layer piece (21) by at least one cut line (22) extending from the tip end to the base end, The other flap has at least one press hole (30) formed therein; A packaging box characterized in that, when closing the top opening of the cylindrical body, the tip side of the other flap is inserted into the cut line of one of the flap, the inner layer piece is placed under the other flap, and the outer layer piece is placed over the other flap, and then pushed into the push hole so that it forms the same surface as the surface of the other flap.

2. The packaging box according to claim 1, characterized in that one of the flaps has an inclined fold line (L4) formed therein, the inclined fold line being inclined away from the inner layer piece from the end of the incision direction of the incision line toward the boundary line (L3) with the side wall.

3. The cut lines are cut into one of the flaps in a pair at a laterally spaced interval, The outer layer piece is provided between a pair of the score lines, The inner layer pieces are provided adjacent to each other on both lateral sides of the outer layer piece via a pair of the cut lines, 2. The packaging box according to claim 1, characterized in that one of the flaps is formed with a pair of inclined fold lines (L4) that incline toward each other from the ends of the pair of incision lines in the incision direction toward a boundary line (L3) with the side wall, and an auxiliary fold line (L5) is formed from the tip of the outer layer piece toward the boundary line so as to horizontally divide one of the flaps into two.

4. A pair of outer layer protrusions (24) are formed on the tip side of the outer layer piece by recessing the central portion in the lateral direction, and protruding relatively.

4. The packaging box according to claim 3, wherein the other flap is formed with a pair of the push holes for pushing in the pair of the outer layer protrusions.

5. 2. The packaging box according to claim 1, characterized in that one of the flaps has a second inclined fold line (L6) formed therein, the second inclined fold line inclining away from the outer layer piece from the end of the incision line in the incision direction toward the boundary line (L3) with the side wall.

6. 6. The packaging box according to claim 1, wherein a tip of the outer layer piece is offset toward the base end from a tip of the inner layer piece.

Images