Packaging box

Abstract

To provide a packaging box capable of suppressing bending of a side plate and maintaining the suppression of the bending even when a heavy article is stored therein.SOLUTION: A packaging box has at least two pairs of side surfaces and a bottom surface, and one pair of side surfaces is connected to the bottom surface via a corrugated ruled line.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] 2. Description of the Related Art Conventionally, packaging boxes (hereinafter simply referred to as packaging boxes) for packaging and storing articles have been widely used in the distribution and transportation of articles.

[0003] A packaging box is assembled into a box shape by forming fold lines on a blank and forming sides that stand up from the bottom at the fold lines, but if the fold lines are straight, the fold lines may act as axes, making the sides prone to tilting outward or inward and curving. For this reason, Patent Document 1, for example, describes a box that makes the fold lines between the bottom and the sides arc-shaped, making it difficult for the sides to tilt outward or inward and suppressing curvature of the sides. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 54-000115 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the box described in Patent Document 1, the folding lines are arc-shaped, so the bottom surface is also deformed into an arc, and if a heavy item is stored in a box with such a deformed bottom surface, the bottom surface will be further deformed, and the side surfaces connected to the bottom surface will also be deformed. As a result, the function of storing items will be reduced, and it is expected that the stored items will fall off the sides during transportation, for example.

[0006] An object of the present invention is to provide a packaging box that can suppress bending of side panels and maintain the suppression of bending even when a heavy item is stored in the box. [Means for solving the problem]

[0007] A first form of the packaging box according to the present invention is a packaging box having at least two pairs of side surfaces and a bottom surface, characterized in that one pair of side surfaces is connected to the bottom surface via a wavy line.

[0008] A second form of the packaging box according to the present invention is the first form described above, characterized in that the wavy lines have at least two or more bulging portions that bulge out toward the side surfaces of the blank before it is assembled into the packaging box.

[0009] A third form of the packaging box according to the present invention is the same as the second form, characterized in that the other pair of side surfaces of the two pairs of side surfaces is provided with a batten portion having a pair of insertion pieces at both ends, and the one pair of side surfaces is provided with a pair of locking portions into which the insertion pieces can be inserted.

[0010] A fourth aspect of the packaging box according to the present invention is the third aspect, characterized in that the pair of locking portions are provided in the vicinity of positions corresponding to the bulging portions.

[0011] A fifth aspect of the packaging box according to the present invention is the first aspect described above, characterized in that the angle formed between the bottom surface and the side surface is an acute angle.

[0012] A sixth form of the packaging box according to the present invention is the first form, characterized in that an engagement hole is provided in a portion of the boundary between the other pair of side surfaces and the bottom surface of the two pairs of side surfaces, and (1) a protrusion is provided on the upper portion of the other pair of side surfaces that can engage with the engagement hole when the packaging boxes are stacked one on top of the other, and / or (2) both ends of one pair of side surfaces are connected to fold-out pieces having protrusions that can engage with the engagement hole when the packaging boxes are stacked one on top of the other, and / or (3) an inner wall portion is connected to the upper edge of the other pair of side surfaces that is folded back inwardly to form a double wall, and an upper portion of the inner wall portion is provided with a protrusion that can engage with the engagement hole when the packaging boxes are stacked one on top of the other.

[0013] A seventh embodiment of the packaging box according to the present invention is a packaging box including a substantially rectangular bottom defined by a pair of first edges and a pair of second edges, a pair of first side faces bent from the bottom via the pair of first edges, and a pair of second side faces bent at right angles from the bottom via the pair of second edges and facing each other, wherein the pair of first edges are formed by wavy lines having at least two or more bulging portions that bulge toward the first side faces in a blank before being assembled into the packaging box, The second side is connected to a batten portion having a pair of insertion pieces at both ends, the pair of first side surfaces are provided with a pair of locking portions into which the insertion pieces can be inserted, the angle formed by the bottom surface and the first side surfaces is acute at least at both ends of the first side surface, an engagement hole portion is provided at the boundary between the pair of second side surfaces and the bottom surface, and both ends of the pair of first side surfaces are provided with folding pieces having protrusions that can engage with the engagement hole portions when the packaging boxes are stacked one on top of the other. Effect of the Invention

[0014] According to the present invention, since the pair of side surfaces and the bottom surface are connected via wavy lines, the shape of the bottom surface is more stable than in the case of arc-shaped lines, so that the curvature of the side surfaces can be suppressed even when a heavy item is stored. In addition, since the shape of the side surfaces becomes wavy and less likely to deform, the strength of the packaging box can be improved. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a perspective view of a packaging box according to a first embodiment of the present invention. [Diagram 2] FIG. 1 is a plan view of a blank in which a packaging box according to a first embodiment of the present invention is unfolded. [Diagram 3] 1A and 1B are plan views for explaining wavy ruled lines according to the first embodiment and its modified example and the third embodiment of the present invention, in which (a) is an enlarged and exaggerated plan view of part IIIa in FIG. 2, (b) is a first modified example of the first embodiment, (c) is a second modified example of the first embodiment, and (d) is a third embodiment. [Figure 4] 4A and 4B are schematic cross-sectional views of a packaging box for explaining the inclination of the bottom and side surfaces according to the first and second embodiments of the present invention, in which (a) is a cross-sectional view taken along the IVa-IVa direction in FIG. 1, and (b) is a similar cross-sectional view of (a) according to the second embodiment. [Diagram 5] FIG. 11 is a plan view of an unfolded blank of a packaging box according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described in detail with reference to Figures 1 to 5. However, the present invention is not limited to this embodiment.

[0017] In this specification and claims, "approximately rectangular" includes not only rectangular and oblong shapes, but also squares and shapes similar thereto, and also shapes with chamfered edges and rounded corners. Furthermore, "approximately rectangular parallelepiped" includes rectangular parallelepipeds, cubes and shapes similar thereto.

[0018] First Embodiment <Packaging box structure> FIG. 1 is a perspective view of a packaging box 10 according to a first embodiment of the present invention, and FIG. 2 is a plan view of a blank 10B of the packaging box 10 according to this embodiment when the box is unfolded.

[0019] The packaging box 10 according to this embodiment has a generally rectangular parallelepiped shape overall, and is a cardboard tray capable of storing items such as fruits and vegetables, agricultural products (e.g., grapes and peaches) inside. However, the present invention is not limited to this, and can be applied to various packaging boxes such as packaging boxes with hexagonal or octagonal bottoms, boxes with bottoms formed by flaps (A-type boxes, etc.), boxes with lids, and boxes with top flaps. Furthermore, in the present invention, the material of the packaging box is not limited to cardboard, and may be, for example, thick paper.

[0020] As shown in Figures 1 and 2, the packaging box 10 of this embodiment has two pairs of first side surfaces 21 and second side surfaces 22 and a bottom surface 11, and the first side surfaces 21 are connected to the bottom surface 11 via a wavy line L1.

[0021] With this configuration, the pair of first side surfaces 21 and bottom surface 11 are connected via wavy lines L1, which prevents first side surface 21 from tilting about said wavy lines L1 as an axis, and prevents curvature of first side surface 21. Also, since the shape of bottom surface 11 is more stable than in the case of arc-shaped lines, the prevention of curvature of first side surface 21 can be maintained even when a heavy item is stored. Also, since the shape of first side surface 21 becomes wavy and is less likely to deform, the strength of packaging box 10 can be improved.

[0022] More specifically, the packaging box 10 includes a substantially rectangular bottom surface 11 defined by a pair of first edges L1 and a pair of second edges L2, a pair of first side surfaces 21 bent from the bottom surface 11 via the pair of first edges L1, and a pair of second side surfaces 22 bent at a right angle from the bottom surface 11 via the pair of second edges L2 and facing each other. The first side surfaces 21 are inclined toward the inside of the packaging box 10 with respect to the bottom surface 11 at least at both ends of the first side surfaces 21 (see FIG. 4(a) described later). Preferably, the first side surfaces 21 rise from the bottom surface 11 at an angle of 85° to 89° at least at both ends of the first side surfaces 21.

[0023] In this embodiment, at least both ends of the first side 21 are inclined toward the inside of the packaging box 10 relative to the bottom surface 11, but both ends of the second side 22 may be inclined toward the inside of the packaging box 10, or both ends of the first side 21 and the second side 22 may be inclined toward the inside of the packaging box 10.

[0024] In the packaging box of this embodiment, as shown in Figures 1 and 2, the second side 22 is provided with a batten portion 32 having a pair of insertion pieces 42 at both ends, and the first side 21 is provided with a pair of locking portions 51 into which the insertion pieces 42 can be inserted.

[0025] With this configuration, the crosspieces 32 are formed, so that the bottom surface 11 of the packaging box 10 can be placed on the crosspieces 32, and the packaging boxes 10 can be stacked stably.

[0026] 1 and 2, the packaging box according to this embodiment has an engagement hole H2 at the center of the boundary between the second side surface 22 and the bottom surface 11, and folded pieces 31 having protrusions 61 that can engage with the engagement hole H2 when the packaging boxes 10 are stacked one on top of the other are provided at both ends of the first side surface 21. Also, in the packaging box according to this embodiment, as shown in Figs. 1 and 2, the boundary between the pair of rails 32 and the pair of second side surfaces 22 has through-holes H3 through which the protrusions 61 pass so as to be able to engage with the engagement hole H2.

[0027] With this configuration, when the packaging boxes 10 are stacked, the protrusions 61 engage with the engagement holes H2, making it possible to stack the packaging boxes 10 more stably. That is, a stacking function can be imparted to the packaging boxes 10, and the strength of the packaging boxes 10 can be maintained while preventing misalignment during stacking.

[0028] In this embodiment, the engagement hole H2 is provided at the center of the boundary between the second side surface 22 and the bottom surface 11, but the present invention is not limited to this. One (or more) engagement holes H2 may be provided at a part of the boundary between the second side surface 22 and the bottom surface 11, and the protrusions 61 may be provided to correspond to the number and position of the engagement holes H2. In addition, in this embodiment, the folding pieces 31 having the protrusions 61 are connected to both ends of the first side surface 21, but the present invention is not limited to this. One (or more) protrusions 61 that can engage with one (or more) engagement holes H2 when the packaging boxes 10 are stacked up and down may be provided on the second side surface 22, or both the protrusions 61 provided on the folding pieces 31 and the protrusions provided on the second side surface 22 may be provided. When provided on both, the protrusions are reinforced.

[0029] The paired folding pieces 31 on the inside of each second side surface 22 are butted together on the inside of the second side surface 22. The butted joints increase the strength of the second side surface 22. The folding pieces 31 do not have to be butted together. The paired folding pieces 31 may have an engagement structure. If the folding pieces have an engagement structure, the crosspieces 32 can be folded while being engaged with each other during assembly, making assembly easier.

[0030] Specific examples of a configuration having a protrusion 61 that can engage with the engagement hole H2 according to the present invention include (A) a crosspiece 32 on the upper edge of the second side surface 22, (A1) a configuration in which a protrusion 61 is provided on the upper portion of the second side surface 22, (A2) a configuration in which folding pieces 31 having protrusions 61 are connected to both ends of the first side surface 21 as in the first embodiment, or a configuration having both of the above (A1) and (A2), and (B) a folding piece 31 is provided on the upper edge of the second side surface 22 instead of the crosspiece 32 as in this embodiment, and is folded toward the inside of the packaging box 10. In the case where the inner wall portion is connected to form a double wall by folding back, the following configurations may be adopted: (B1) a configuration in which a protrusion 61 is provided on the upper part of the second side surface 22; (B2) a configuration in which a fold-in piece 31 having a protrusion 61 is connected to both ends of the first side surface 21; (B3) a configuration in which a protrusion 61 is provided on the upper part of the inner wall portion (the upper part of the upright inner wall portion when the packaging box is in an assembled state); or a configuration having two or more of the above (B1), (B2), and (B3) (including the case where all three are selected).

[0031] <Packaging box blank> Turning to Figure 2, in the blank 10B of the packaging box 10 in this embodiment, a pair of first side surfaces 21 are connected to the bottom surface 11 via a first edge (first fold line) L1, and a pair of second side surfaces 22 are connected to the bottom surface 11 via a second edge (second fold line) L2.

[0032] The pair of rails 32 are connected to the pair of second side surfaces 22 via the third edge (third folding line) L3, and the pair of insertion pieces 42 are connected to the rails 32 via the fourth edge (fourth folding line) L4. The pair of locking parts 51 are connected to the first side surface 21 via the fifth edge (fifth folding line) L5, and the pair of folding pieces 31 having the protrusions 61 at their tips are connected to both ends of the first side surface 21 via the sixth edge (sixth folding line) L6. The folding pieces 31 have an angle (θ1) formed between the side adjacent to the second side surface 22 and the sixth edge (sixth folding line L6) that is an acute angle of less than 90°, and an angle (θ2) formed between the side adjacent to the second side surface 22 and the second edge (second folding line) L2 that is an obtuse angle. Preferably, the angle θ1 is 85° to 89°.

[0033] In the blank 10B in this embodiment, the first folding line L1, the fourth folding line L4, and the fifth folding line L5 are set to be horizontal creases (so-called scores) of the cardboard, and the second folding line L2, the third folding line L3, and the sixth folding line L6 are set to be vertical creases (so-called creases) of the cardboard. The direction in which the creases are formed is not limited to this, and they may be formed in any direction as long as the object of the present invention can be achieved. The creases in this embodiment are formed, for example, by pressing a pressing member from one side. The creases may be formed, for example, by including lead creases or cut lines.

[0034] Fig. 3 is a plan view for explaining the wavy ruled lines according to this embodiment, its modified examples, and the third embodiment, Fig. 3(a) is an enlarged and exaggerated plan view of part IIIa in Fig. 2, Fig. 3(b) is a first modified example of this embodiment, Fig. 3(c) is a second modified example of this embodiment, and Fig. 3(d) is the third embodiment described below. The dashed lines in Fig. 3 are straight lines connecting the corners of the packaging box 10.

[0035] The wavy line L1 is a curved or bent curved line that bulges toward the first side surface 21. In this embodiment, as shown in FIG. 3(a), the wavy line L1 has two side bulging portions Ea that bulge toward the first side surface 21 in the blank 10B before assembly into the packaging box 10. The bulging portion is referred to as a protruding portion as shown in FIG. 3. In the present invention, it is preferable that there are at least two side bulging portions Ea, but the number of waves may be any number. It is preferable that the shape of the wavy line L1 is line symmetrical with respect to a straight line drawn to divide the line L1 in two in the extension direction. It is also preferable that the start point of the wave is aligned with the position of a corner of the packaging box 10.

[0036] In a first modified example of this embodiment, as shown in FIG. 3(b), two side bulges Ea of the wavy ruled line L1' protrude to the side, and one bottom bulge Eb protrudes to the bottom. In a second modified example of this embodiment, as shown in FIG. 3(c), two bottom bulges Eb of the wavy ruled line L1'' protrude to the bottom. The present invention can also allow aspects such as the first and second modified examples. Also, the corners of the packaging box may not be the starting points of the waves, and may have a straight line portion at the corners of the packaging box (see FIG. 3(d). Details will be described later). In addition, there may be a straight line extending portion between the multiple bulges Ea.

[0037] <Assembly Instructions> Regarding the assembly procedure of this embodiment, for example, first, from the state of the blank 10B in FIG. 2, a pair of first side surfaces 21 are raised from the bottom surface 11 via the first folding line L1, a pair of second side surfaces 22 are raised from the bottom surface 11 via the second folding line L2, next, two pairs of insertion pieces 42 are each folded at a right angle from the fourth folding line L4, two pairs of locking portions 51 are each folded at a right angle from the fifth folding line L5, The two pairs of folding pieces 31 of the pair of first side surfaces 21 are each folded at a right angle from the sixth folding line L6, and then the two pairs of folding pieces 31 are positioned inside the packaging box 10, and the pair of bar portions 32 of the pair of second side surfaces 22 are each folded from the third folding line L3 so that the protrusions 61 of the two pairs of folding pieces 31 are each inserted into the through-hole portions H3, and the two pairs of insertion pieces 42 are inserted into the holes of the two pairs of engagement portions 51, resulting in the state shown in Figure 1.

[0038] Conventionally, packaging boxes for packaging and storing goods have been widely used in the distribution process of goods, and such packaging boxes are assembled into a box shape by forming fold lines on a blank and forming sides that stand up from the bottom at the fold lines, but if the fold lines are straight, the fold lines may act as axes and cause the sides to bend and tilt toward the outside or inside of the box. Therefore, for example, Patent Document 1 describes a box in which the fold lines between the bottom and the sides are made arc-shaped to make it difficult for the sides to tilt toward the outside or inside of the box and suppress the curvature of the sides.

[0039] However, in the box described in Patent Document 1, the folding lines are arc-shaped, so the bottom surface is also deformed into an arc, and if a heavy item is stored in a box with such a deformed bottom surface, the bottom surface will be further deformed, and the side surfaces connected to the bottom surface will also be deformed. As a result, the function of storing items will be reduced, and it is expected that the stored items will fall off the sides during transportation, for example.

[0040] According to this embodiment, the pair of first side surfaces 21 and the bottom surface 11 are connected via the wavy lines L1, so that the shape of the bottom surface 11 is more stable than in the case of an arc-shaped line, and therefore the curvature of the first side surface 21 can be suppressed even when a heavy item is stored. In addition, the shape of the first side surface 21 becomes wavy and is less likely to deform, so that the strength of the packaging box 10 can be improved. That is, by generating a moderate undulation in the first side surface 21, the compressive strength in the vertical direction of the first side surface 21 is increased, and the curvature in the vertical direction of the bottom surface 11 is suppressed to a minimum. In other words, the distortion generated in the bottom surface 11 can be reduced, and rattling can be suppressed. Since multiple wave crests are provided on the first side surface 21, the part receiving the force can be dispersed.

[0041] Furthermore, according to this embodiment, the material of the packaging box 10 is cardboard, and the corrugated core is sandwiched between a front liner and a back liner, and the core has a so-called truss structure. In addition to this structure, the first side surface 21 is corrugated, which can improve the strength of the first side surface 21.

[0042] Furthermore, according to this embodiment, the strength of the first side surface 21 is improved, so that the packaging boxes 10 can be stacked stably.

[0043] According to this embodiment, in the blank 10B, the angle (θ2) formed by the side of the folding piece 31 adjacent to the second side surface 22 of the folding piece 31 and the second edge (second folding line) L2 is an obtuse angle and extends in a direction away from the edge of the second side surface 22, so that the first side surface 21 is inclined toward the inside of the packaging box 10 with respect to the bottom surface 11, allowing the packaging boxes 10 to be stably stacked. In addition, the compression strength of the first side surface 21 can be improved.

[0044] According to this embodiment, the first edge L1 of the bottom surface 11 is wavy, so that the ground contact portion is increased, and the packaging box 10 can be placed stably.

[0045] Fig. 4 is a schematic cross-sectional view of a packaging box for explaining the inclination of the bottom surface 11 and the first side surface 21 according to this embodiment and the second embodiment described later, Fig. 4(a) is a cross-sectional view in the IVa-IVa direction of Fig. 1, and Fig. 4(b) is a cross-sectional view similar to Fig. 4(a) according to the second embodiment described later. The IVa-IVa direction cross-sectional view of Fig. 1 is a cross-sectional view seen from the inside of the packaging box 10 as shown in Fig. 1, and is a cross-sectional view of the end of the bottom surface 11 and the first side surface 21 just before the butting portion of the folding piece 31 of the packaging box 10. In Fig. 4, the bottom surface 11 and the first side surface 21 of the packaging box 10 (or 10') are represented by lines with no thickness for convenience of explanation.

[0046] 4(a), as described above, the angle (θ3) formed between the bottom surface 11 and the first side surface 21 is an acute angle. That is, in the packaging box 10 according to the first embodiment, the first side surface 21 is inclined toward the inside of the packaging box 10 with respect to the bottom surface 11.

[0047] In the second embodiment of the present invention, as shown in Fig. 4(b), the angle formed between the bottom surface 11 and the first side surface 21 is a right angle. Even in this case, it is possible to obtain the effects of the present invention.

[0048] <Second embodiment> 5 is a plan view of a blank 10'B in which a packaging box 10' according to a second embodiment of the present invention is unfolded. Among the elements constituting the packaging box 10' and blank 10'B according to this embodiment, those having similar functions are given the same reference numerals as in the first embodiment, and the description thereof will be omitted.

[0049] In this embodiment, the folding piece 31' is configured so that the blank 10'B extends parallel to the extending direction of the first side surface 21 so that the first side surface 21 can stand upright from the bottom surface 11. The folding piece 31' has an angle (θ4) formed between the side adjacent to the second side surface 22 and the sixth edge (sixth folding line) L6, which is a right angle.

[0050] According to this embodiment, as in the first embodiment, even when heavy items are stored, curvature of the first side 21 can be suppressed, the strength of the packaging box 10 can be improved, and the packaging boxes 10 can be stacked stably, and the volume for storing items can be increased compared to the first embodiment.

[0051] <Third embodiment> In the third embodiment of the present invention, as shown in Fig. 3(d), unlike the first embodiment, the corrugated ruled line L1''' does not start at the corner of the packaging box where the waves begin, but has some straight line portions SL at the corner of the packaging box, and a pair of side bulging portions Ea that bulge toward the first side surface 21 are connected to the pair of straight line portions SL. Of the elements constituting this embodiment, those having similar functions are given the same reference numerals as in the first embodiment, and their description will be omitted.

[0052] In this embodiment, a pair of locking portions 51 are provided in the vicinity of positions corresponding to the side bulges Ea of the wavy ruled lines L1'''.

[0053] With this configuration, when stacked, the load is mainly applied to the crosspieces 32, but the load resistance is improved in the multiple arch-shaped portions included in the corrugations, thereby improving the strength of the packaging box.

[0054] The present invention is not limited to the above-described embodiments or the modified examples described throughout the specification, and appropriate changes and modifications can be made without departing from the technical concept of the present invention. [Explanation of symbols]

[0055] 10, 10' packaging box 10B, 10'B Packaging Box Blanks 11 Bottom Ea Side bulge Eb Bottom side bulge 21 First aspect 22 Second aspect 31, 31' Fold-in piece 32 Cross section 42 Insert 51 Locking part 61 Protrusion H2 Engagement hole H3 through hole L1~L6 1st to 6th ruled lines (edges, fold lines)

Claims

1. A packaging box having at least two pairs of side surfaces and a bottom surface, wherein one pair of side surfaces is connected to the bottom surface via a wavy line.

2. 2. The packaging box according to claim 1, wherein the wavy lines have at least two bulging portions that bulge out toward the side surfaces of the blank before it is assembled into the packaging box.

3. The other pair of side surfaces of the two pairs of side surfaces is provided with a rib portion having a pair of insertion pieces at both ends, 3. The packaging box according to claim 2, wherein one of the pair of side surfaces is provided with a pair of locking portions into which the insertion piece can be inserted.

4. 4. The packaging box according to claim 3, wherein the pair of locking portions are provided in the vicinity of positions corresponding to the bulging portions.

5. 2. The packaging box according to claim 1, wherein the angle formed between the bottom surface and the side surface is an acute angle at least at both ends of the side surface.

6. An engagement hole is provided at a part of a boundary between the other pair of side surfaces and the bottom surface, (1) A configuration in which a protrusion that can be engaged with the engagement hole when the packaging boxes are stacked one on top of the other pair of side surfaces is provided on the upper part of the other pair of side surfaces; and / or (2) A configuration in which a folding piece having a protrusion that can engage with the engagement hole when the packaging boxes are stacked one on top of the other is provided at both end portions of the pair of side surfaces of the one of the pair of side surfaces; and / or (3) An inner wall portion is provided on the upper edge of the other pair of side surfaces so as to be folded inwardly to form a double wall, and a protrusion portion is provided on the upper portion of the inner wall portion, which is capable of engaging with the engaging hole portion when the packaging boxes are stacked one on top of the other. The packaging box of claim 1, further comprising:

7. a substantially rectangular bottom surface defined by a pair of first edges and a pair of second edges; a pair of first side surfaces bent from the bottom surface via the pair of first edges; A packaging box including a pair of second side surfaces bent at a right angle from the bottom surface via the pair of second edges and facing each other, The pair of first edges are formed by wavy lines having at least two or more bulging portions that bulge toward the first side surface in the blank before being assembled into the packaging box, A pair of second side surfaces are connected to a rail portion having a pair of insertion pieces at both ends, The pair of first side surfaces are provided with a pair of locking portions into which the insertion pieces can be inserted, an angle formed between the bottom surface and the first side surface is an acute angle at least at both ends of the first side surface, An engagement hole is provided at a boundary between the pair of second side surfaces and the bottom surface, A packaging box characterized in that folding pieces having protrusions that can engage with the engagement holes when the packaging boxes are stacked one on top of the other are provided at both ends of the pair of first sides.

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