Packing box

Abstract

To provide a packaging box that can reduce entry of foreign matters into the packaging box and can be surely assembled.SOLUTION: A packaging box 10, 20, 30 is of a rectangular parallelepiped wrap-around case type. The distal end edges of a pair of outer flaps 18, 28, 38 are opposite to each other at a predetermined interval. The distal end part of a left inner flap 17L, 27L, 37L is overlapped with the outer surface of a right inner flap 17R, 27R, 37R at least in a region between the distal end edges of the pair of outer flaps 18, 28, 38. The outer flaps 18 or the right inner flap 27R, 37R have an approach fold line b, i, i' for bending them to approach each other.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Conventionally, a rectangular parallelepiped wraparound case type packaging box capable of accommodating a plurality of products has been known (see Patent Document 1).

[0003] This packaging box has a rectangular tube-shaped body portion extending in the horizontal direction and a pair of closing portions that respectively close the open ends of the body portion. This body portion is assembled by sequentially folding a top plate, a bottom plate, and a pair of side plates connected via body fold lines along the body fold lines. The closing portion is assembled by folding all of a pair of inner flaps respectively connected to the pair of side plates and a pair of outer flaps respectively connected to the top plate and the bottom plate inward along inner flap fold lines and outer flap fold lines, and fixing the outer flaps to the outer surfaces of the inner flaps with an adhesive.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, this packaging box has a problem that if there are gaps between the pair of inner flaps and between the pair of outer flaps in the assembled state, foreign matter may enter through these gaps.

[0006] One possible solution to this problem is to butt the leading edges of the opposing flaps together to eliminate the gap. However, because there is always some error in the position where the corrugated cardboard is folded, maintaining the precision required to butt the leading edges of the opposing flaps together without any gaps in mass-produced packaging boxes is not easy.

[0007] On the other hand, one possible solution to the problem is to overlap the tips of the opposing flaps. However, overlapping the flaps creates a step, which presents a new problem: the inner and outer flaps cannot be sufficiently pressed together with adhesive, resulting in weaker fixation.

[0008] This invention was made to solve these problems and aims to provide a packaging box that can reduce the inclusion of foreign matter inside the packaging box and can be assembled reliably. [Means for solving the problem]

[0009] To achieve this objective, the first packaging box of the present invention is a packaging box having a rectangular cylindrical body and a pair of closing parts that close the open ends of the body, wherein the body is composed of a top plate, a bottom plate and a pair of side wall plates connected via body fold lines, and the closing parts have a pair of inner flaps connected to the pair of side wall plates via inner flap fold lines and a pair of outer flaps connected to the top plate and the bottom plate via outer flap fold lines and fixed to the outer surface of the inner flaps, wherein the pair of outer flaps have their leading edges facing each other with a predetermined distance between them, the leading edge of one inner flap overlaps the outer surface of the other inner flap in a region sandwiched between at least the leading edges of the pair of outer flaps, and the outer flaps or the other inner flap have approach fold lines that cause them to bend themselves to bring them closer together.

[0010] In the first packaging box of the present invention, the leading edges of a pair of outer flaps face each other with a predetermined distance between them, and the leading edge of one inner flap overlaps the outer surface of the other inner flap in a region that is sandwiched between the leading edges of the pair of outer flaps.

[0011] Therefore, according to the first packaging box of the present invention, the gap between the leading edges of a pair of outer flaps can be filled by the leading edge of one inner flap overlapping the outer surface of the other inner flap, thereby reducing the gap that allows communication from the outside to the inside of the packaging box, and thus suppressing the intrusion of foreign matter into the inside of the packaging box.

[0012] Furthermore, in the first packaging box of the present invention, a step is created when one inner flap overlaps the outer surface of the other inner flap. As a result, the outer flap overlaps the outer surface of these inner flaps, the upper inner flap is more likely to come into contact with the outer flap, while the lower inner flap is less likely to come into contact with the outer flap because it is pushed into the internal space of the packaging box by the other inner flap.

[0013] However, in the first packaging box of the present invention, since the outer flap or the other inner flap has a fold line, the outer flap and the other inner flap can be brought closer together by bending themselves (the outer flap or the other inner flap) along the fold line.

[0014] Therefore, according to the first packaging box of the present invention, the inner flap and the outer flap can be sufficiently pressed together with adhesive, thus ensuring reliable assembly.

[0015] The second packaging box of the present invention is a packaging box having a rectangular cylindrical body and a pair of closing parts that close the open ends of the body, wherein the body is composed of a top plate, a bottom plate and a pair of side wall plates connected via body fold lines, and the closing parts have a pair of inner flaps connected to the pair of side wall plates via inner flap fold lines and a pair of outer flaps connected to the top plate and the bottom plate via outer flap fold lines and fixed to the outer surface of the inner flaps, wherein the pair of outer flaps have their leading edges facing each other with a predetermined distance between them, the leading edge of one inner flap overlaps the outer surface of the other inner flap in a region sandwiched between at least the leading edges of the pair of outer flaps, and the outer flap fold lines are formed convexly in a direction away from the leading edge of the outer flap, connecting both corners on the base end side of the outer flap.

[0016] In the second packaging box of the present invention, the leading edges of a pair of outer flaps face each other with a predetermined distance between them, and the leading edge of one inner flap overlaps the outer surface of the other inner flap in a region sandwiched between the leading edges of the pair of outer flaps.

[0017] Therefore, according to the second packaging box of the present invention, the gap between the leading edges of a pair of outer flaps can be filled by the leading edge of one inner flap overlapping the outer surface of the other inner flap, thereby reducing the gap that allows communication from the outside to the inside of the packaging box, and thus suppressing the intrusion of foreign matter into the inside of the packaging box.

[0018] Furthermore, in the second packaging box of the present invention, a step is created when one inner flap is superimposed on the outer surface of the other inner flap. As a result, one inner flap is easily in contact with the outer flap, while the other inner flap is pushed into the internal space of the packaging box by the other inner flap, making it less likely for it to come into contact with the outer flap.

[0019] However, in the second packaging box of the present invention, the outer flap is connected to the body (top plate and bottom plate) via an outer flap crease line that connects both corner portions on the base end side and is formed in a convex shape in a direction away from the tip of the outer flap.

[0020] Therefore, when bent along the outer flap crease line, the central portion in the width direction of the outer flap is bent so as to protrude toward the inner space of the packaging box. As a result, the outer flap can also approach the other inner flap that is pushed downward (toward the inner space of the packaging box) by one inner flap.

[0021] Thus, according to the second packaging box of the present invention, it is easy to press-bond the inner flap and the outer flap with an adhesive, so that the assembly can be surely performed.

[0022] In the second packaging box of the present invention, it is preferable that the outer flap crease line is formed in a V shape in which two straight portions are connected by a bent portion, and the outer flap has an outer flap valley crease line extending from the bent portion to the middle portion of the leading edge of the outer flap.

[0023] According to the second packaging box of the present invention having this configuration, when the outer flap is bent along the V-shaped flap crease line and the outer flap valley crease line, it is valley-folded along the outer flap valley crease line and bent substantially in a V shape toward the inner space of the packaging box. As a result, the outer flap can also approach the other inner flap that is pushed downward (toward the inner space of the packaging box) by one inner flap.

[0024] Thus, according to the second packaging box of the present invention having this configuration, it is easy to press-bond the inner flap and the outer flap with an adhesive, so that the assembly can be surely performed.

[0025] Furthermore, in the second packaging box of the present invention having the above configuration (V-shaped outer flap crease line and outer flap valley crease line), it is preferable that the distance from the outer flap valley crease line of the outer flap to the base end of the one inner flap is the same as or greater than the distance from the base end to the tip of the one inner flap.

[0026] In the second packaging box of the present invention having this configuration, in the outer flaps, the portion along the outer flap valley fold line that is bent in a V shape and protrudes toward the inner space side of the packaging box is disposed on the side of the other inner flap rather than on the side of one inner flap.

[0027] Therefore, according to the second packaging box of the present invention having this configuration, the outer flap can be surely brought close to the other inner flap. Thus, according to the second packaging box of the present invention having this configuration, it is easy to crimp the inner flap and the outer flap with an adhesive, so that the assembly can be surely performed.

[0028] The third packaging box of the present invention is a packaging box having a rectangular tubular body portion and a pair of closing portions that respectively close the open ends of the body portion. The body portion is formed by connecting a top plate, a bottom plate, and a pair of side wall plates via body fold lines. The closing portion has a pair of inner flaps connected to the pair of side wall plates via inner flap fold lines, and a pair of outer flaps connected to the top plate and the bottom plate via outer flap fold lines and fixed to the outer surfaces of the inner flaps. The pair of outer flaps have their leading edges facing each other with a predetermined interval therebetween. The leading end portion of one inner flap is overlapped with the outer surface of the other inner flap in a region sandwiched between the leading edges of at least the pair of outer flaps. The other inner flap has an inner flap mountain fold line connecting both side edges of the other inner flap on the leading end side of the inner flap fold line.

[0029] In the third packaging box of the present invention, where the leading edges of the pair of outer flaps face each other with a predetermined interval therebetween, the leading end portion of one inner flap is overlapped with the outer surface of the other inner flap in a region sandwiched between the leading edges of at least the pair of outer flaps.

[0030] Therefore, according to the third packaging box of the present invention, the gap between the leading edges of a pair of outer flaps can be filled by the leading edge of one inner flap overlapping the outer surface of the other inner flap, thereby reducing the gap that allows communication from the outside to the inside of the packaging box, and thus suppressing the intrusion of foreign matter into the inside of the packaging box.

[0031] Furthermore, in the third packaging box of the present invention, a step is created when one inner flap overlaps the outer surface of the other inner flap. As a result, one inner flap is more likely to come into contact with the outer flap, while the other inner flap is less likely to come into contact with the outer flap because it is pushed into the internal space of the packaging box by the other inner flap.

[0032] However, in the third packaging box of the present invention, the other inner flap has an inner flap mountain fold line that connects both side edges of the other inner flap, located on the tip side of the inner flap fold line.

[0033] Therefore, the other inner flap can be folded along the inner flap's mountain fold line, causing it to protrude towards the external space of the packaging box with the mountain fold line as its ridge. This allows the other inner flap to be brought closer to the outer flap, even if the leading edge of one inner flap is pushed downwards (towards the internal space of the packaging box).

[0034] Therefore, according to the third packaging box of the present invention, the inner flap and the outer flap can be easily pressed together with adhesive, thus ensuring reliable assembly.

[0035] In the third packaging box of the present invention, it is preferable that the inner flap fold line provided along the base end of the other inner flap is formed in an arc shape that connects both corners on the base end side of the other inner flap and bulges in a direction away from the tip of the other inner flap, and the inner flap mountain fold line is formed in an arc shape that connects both corners on the base end side of the other inner flap and bulges in a direction approaching the tip of the other inner flap.

[0036] In the third packaging box of the present invention having this configuration, since the inner flap fold line and the inner flap mountain fold line have common ends, simply by folding the other inner flap inward into the packaging box, the other inner flap folds sequentially along the inner flap fold line and the inner flap mountain fold line.

[0037] Furthermore, both the inner flap fold line and the inner flap mountain fold line are arc-shaped. Folding along an arc-shaped fold line does not result in a natural bend; it requires a slight forced bend while allowing the entire packaging box to bend. As a result, even when the other inner flap is folded along the inner flap fold line and the inner flap mountain fold line, a strong restoring force is generated that tries to return it to its original state (position along the body). Therefore, when the outer surface of the tip of the other inner flap is pressed against the other inner flap, the restoring force causes the entire flap (including the part along the inner flap mountain fold line) to repel and protrude towards the external space of the packaging box.

[0038] Therefore, with the third packaging box of the present invention having this configuration, when the outer flap is pressed from the outside via adhesive, the other inner flap attempts to resist it due to the restoring force, making it easier to press the inner flap and outer flap together with adhesive. Therefore, with the third packaging box of the present invention having this configuration, assembly can be carried out reliably.

[0039] In the third packaging box of the present invention, it is preferable that the inner flap fold line provided along the base end of the other inner flap is formed in a straight line so as to be paired with the inner flap fold line provided along the base end of the one inner flap, and the inner flap mountain fold line is formed in a straight line connecting the intermediate portions of both side edges of the other inner flap.

[0040] According to the third packaging box of the present invention having this configuration, the other inner flap is folded along an inner flap fold line provided along its base end so as to lie on the same plane as the first inner flap, and the tip of the other inner flap is folded along an inner flap mountain fold line and overlapped with the inner surface side of the first inner flap.

[0041] In this case, since the inner flap fold line and inner flap peak fold line of the other inner flap are straight, the other inner flap does not curve, and the area sandwiched between the inner flap fold line and the inner flap peak fold line can be placed on the same plane as the other inner flap. Therefore, the area of ​​the other inner flap sandwiched between the inner flap fold line and the inner flap peak fold line can be bonded to the outer flap surface to surface.

[0042] Therefore, according to the third packaging box of the present invention having this configuration, the inner flap and the outer flap can be easily pressed together with adhesive, thus ensuring reliable assembly. [Brief explanation of the drawing]

[0043] [Figure 1] This is a perspective view showing the appearance of the packaging box according to the first embodiment. [Figure 2] This is a plan view showing the configuration of the packaging box according to the first embodiment before assembly. [Figure 3] This is an end view showing the end face of line AA in Figure 1. [Figure 4] This is a perspective view showing the appearance of the packaging box according to the second embodiment. [Figure 5] This is a plan view showing the configuration of the packaging box according to the second embodiment before assembly. [Figure 6] Figure 4 is an end view showing the end face of line BB. [Figure 7] This is a plan view showing the configuration of the packaging box according to the third embodiment before assembly. [Figure 8] This is an end view showing the end face when the third embodiment is cut at the same position as line BB in Figure 4. [Modes for carrying out the invention]

[0044] [First Embodiment] The packaging box 10 according to the first embodiment of the present invention will be described below with reference to Figures 1 to 3. The packaging box 10 according to the first embodiment corresponds to the first packaging box and the second packaging box of the present invention described in the means for solving the problem.

[0045] As shown in Figure 1, the packaging box 10 of the first embodiment is a wrap-around case type with an external appearance formed in the shape of a rectangular parallelepiped. The packaging box 10 has a rectangular cylindrical body portion 12 that extends horizontally and a closing portion 13 that closes the open end of the body portion 12. When viewed from the closing portion 13 side, the packaging box 10 of the first embodiment is formed in a vertically elongated shape in which the height (length in the vertical direction) is longer than the width (length in the horizontal direction).

[0046] The body section 12 comprises a top plate 14, a bottom plate 15, and a pair of side plates 16. The pair of side plates 16 include the left side plate 16L on the rear (left) side in Figure 1 and the right side plate 16R on the front (right) side.

[0047] The closure section 13 comprises an inner flap 17 and a pair of outer flaps 18.

[0048] The pair of inner flaps 17 includes a left inner flap 17L connected to the left side plate 16L (corresponding to "one inner flap" in the present invention) and a right inner flap 17R connected to the right side plate 16R (corresponding to "the other inner flap" in the present invention). In Figure 1, the tip of the left inner flap 17L overlaps the outer surface of the right inner flap 17R.

[0049] A pair of outer flaps 18 face each other with their leading edges separated by a predetermined distance. A valley fold line c is formed in the center of the outer flap 18 in the width direction, connecting the upper and lower ends. The outer flap 18 is folded along the valley fold line c, so that in a plan view it is folded into a V shape toward the internal space of the packaging box.

[0050] Furthermore, the outer flap 18 is fixed to the outer surface of the inner flap 17 (left inner flap 17L and right inner flap 17R) via adhesive G.

[0051] The packaging box 10 is formed by punching out a roughly rectangular corrugated cardboard sheet 10x, as shown in Figure 2, from a base paper, and then folding and assembling it. The structure of the corrugated cardboard sheet 10x will be described below with reference to Figure 2.

[0052] As shown in Figure 2, the corrugated cardboard sheet 10x is arranged in the following order from left to right: left panel 16L, bottom panel 15, right panel 16R, top panel 14, and adhesive piece 19, each connected via a fold line a on the body. The top panel 14, bottom panel 15, left panel 16L, and right panel 16R are all formed in a roughly rectangular shape, and the adhesive piece 19 is formed in a roughly inverted trapezoidal shape.

[0053] The top panel 14 has outer flaps 18 connected to its upper and lower ends via outer flap fold lines b (which correspond to the "outer flap fold line" of the second packaging box of the present invention, and also to the "proximity fold line" of the first packaging box of the present invention). The outer flaps 18 are all formed in a roughly pentagonal shape.

[0054] The outer flap fold line b is formed in a V-shape that protrudes towards the body portion 12 beyond the extension of the inner flap fold line d, which will be described later. More specifically, the outer flap fold line b is formed in a V-shape by connecting the outer flap left fold line b1 (corresponding to the "straight portion" of the present invention), which is formed in a straight line on the right side in Figure 2, and the outer flap right fold line b2 (corresponding to the "straight portion" of the present invention), which is formed in a straight line on the left side in Figure 2, at the bent portion 18a. The outer flap left fold line b1 is designed to be longer than the outer flap right fold line b2.

[0055] Furthermore, the outer flap 18 has an outer flap valley fold line c that extends along the body fold line a from the bent portion 18a to the middle of its tip edge. The outer flap valley fold line c divides the outer flap 18 into the left half 18L of the outer flap on the right side in Figure 2 and the right half 18R of the outer flap on the left side in Figure 2. The width of the left half 18L of the outer flap is designed to be longer than the width of the right half 18R of the outer flap. The width of this left half 18L of the outer flap is designed to be approximately the same length as the length from the base to the tip of the left inner flap 17L.

[0056] Outer flaps 18 are connected to the top and bottom ends of the base plate 15 via outer flap fold lines b (corresponding to the "outer flap fold line" of the second packaging box of the present invention, and also to the "proximity fold line" of the first packaging box of the present invention). Both outer flaps 18 are formed in a roughly pentagonal shape. The combined length of the lengths of a pair of outer flaps 18 from their base to their tips is designed to be smaller than the width (left-right direction in Figure 2) of the inner flaps 17 (left inner flap 17L and right inner flap 17R).

[0057] The outer flap fold line b is formed in a V-shape that protrudes towards the body portion 12 from the extension of the inner flap fold line d, which will be described later. More specifically, the outer flap fold line b is formed in a V-shape by connecting the outer flap left fold line b1 (corresponding to the "straight portion" of the present invention), which is formed in a straight line on the left side in Figure 2, and the outer flap right fold line b2 (corresponding to the "straight portion" of the present invention), which is formed in a straight line on the right side in Figure 2, at the bent portion 18a. The outer flap left fold line b1 is designed to be longer than the outer flap right fold line b2.

[0058] Furthermore, the outer flap 18 has an outer flap valley fold line c that extends parallel to the body fold line a from the bent portion 18a to the middle of its tip edge. The outer flap valley fold line c divides the outer flap 18 into the left half 18L of the outer flap on the right side in Figure 2 and the right half 18R of the outer flap on the left side in Figure 2. The width of the left half 18L of the outer flap is designed to be longer than the width of the right half 18R of the outer flap. The width of this left half 18L of the outer flap is designed to be approximately the same length as the length from the base to the tip of the left inner flap 17L.

[0059] In Figure 2, the left inner flap 17L is attached to the upper and lower ends of the left inner flap 16L via the inner flap fold line d. The left inner flap 17L is formed in a roughly rectangular shape. The right inner flap 17R is attached to the upper and lower ends of the right inner flap 16R via the inner flap fold line d. The left inner flap 17R is formed in the same roughly rectangular shape as the left inner flap 17L.

[0060] The sum of the length from the base to the tip of the left inner flap 17L and the length from the base to the tip of the left inner flap 17R is designed to be larger than the width of the top plate 14 and the bottom plate 15 (or outer flap 18).

[0061] Next, we will explain the procedure for assembling the packaging box 10 shown in Figure 1 from the corrugated cardboard sheets 10x shown in Figure 2.

[0062] First, the worker places the corrugated cardboard sheets 10x on a table (not shown), for example, and then places multiple products (not shown) on the base plate 15 in an orderly fashion.

[0063] Next, in Figure 2, the left side plate 16L, which is positioned to the left of the base plate 15, is folded along the body fold line a and stands upright at a right angle to the base plate 15. Then, adhesive G (not shown) is applied to the outer surface of the upper end of the upright left side plate 16L.

[0064] Next, by sequentially folding along the fold line a located on the right side of the base plate 15, the right side plate 16R is raised perpendicular to the base plate 15, the top plate 14 is made parallel to the base plate 15, and the adhesive piece 19 hangs down. Then, the inner surface of the adhesive piece 19 is fixed to the outer surface of the left side plate 16L via adhesive G, thereby assembling the body 12.

[0065] Next, the right inner flap 17R is folded inward toward the body 12 at the inner flap fold line d, perpendicular to the right side panel 16R, and the left inner flap 17L is folded inward toward the body 12 at the inner flap fold line d, perpendicular to the left side panel 16L.

[0066] At this time, the sum of the length from the base to the tip of the left inner flap 17L and the length from the base to the tip of the left inner flap 17R is greater than the width of the top plate 14 and the bottom plate 15. Therefore, the tip of the left inner flap 17L overlaps with the outer surface of the right inner flap 17R, as shown in Figure 3. As a result, in the closing portion 13 of the packaging box 10, the left inner flap 17L overlaps with the outer surface of the right inner flap 17R, and the right inner flap 17R is pushed into the internal space of the packaging box 10, creating a step.

[0067] Next, as shown in Figure 1, adhesive G is applied to the outer surfaces of the left inner flap 17L and the right inner flap 17R at the positions where the outer flap 18 will overlap.

[0068] Next, as shown in Figure 1, the lower outer flap 18 is folded upward along the outer flap fold line b, and the inner surface of the lower outer flap 18 is fixed to the outer surface of the inner flap 7 (left inner flap 17L and right inner flap 17R) via adhesive G. The upper outer flap 18 is folded downward along the outer flap fold line b, and the inner surface of the upper outer flap 18 is fixed to the outer surface of the inner flap 7 (left inner flap 17L and right inner flap 17R) via adhesive G.

[0069] At this time, the combined length of the pair of outer flaps 18 from their base to their tip is designed to be smaller than the widthwise length (vertical direction in Figure 1) of the inner flaps 17 (left inner flap 17L and right inner flap 17R). As a result, the tip edges of the pair of outer flaps 18 face each other with a predetermined distance between them. This closes the open end of the body portion 12, forming the closed portion 13.

[0070] Next, Figure 3 will be used to provide a supplementary explanation of how the outer flap 18 deforms when it is folded along the outer flap fold line b.

[0071] First, since the outer flap fold line b is bent in a V-shape, when the outer flap 18 is folded along the outer flap fold line b, it is bent so that the central part in the width direction protrudes in a V-shape toward the internal space of the packaging box 10.

[0072] In particular, the outer flap 18 has an outer flap valley fold line c that extends parallel to the body fold line a from a bent portion 18a located near the center in the width direction to the middle of the leading edge of the outer flap 18. Therefore, the outer flap 18 is valley-folded along the outer flap valley fold line c. As a result, the outer flap 18 is easily bent into a V-shape toward the internal space of the packaging box 10.

[0073] Furthermore, this valley fold divides the outer flap 18 into the left half 18L of the outer flap and the right half 18R of the outer flap, as it is folded along the outer flap valley fold line c.

[0074] Furthermore, since the width of the left half of the outer flap 18L is designed to be almost the same as the length from the base to the tip of the left inner flap 17L, which is positioned above it, almost the entire inner surface of the left half of the outer flap 18L comes into surface-to-surface contact with almost the entire outer surface of the left inner flap 17L by slightly pushing the left inner flap 17L in.

[0075] Furthermore, since the width of the left half 18L of the outer flap is designed to be approximately the same as the length from the base to the tip of the left inner flap 17L, which is positioned above it, the valley fold line c of the outer flap is positioned to be in contact with the tip edge of the left inner flap 17L. As a result, almost the entire inner surface of the right half 18R of the outer flap and most of the outer surface of the right inner flap 17R (excluding the tip portion hidden by the left inner flap 17L) are in surface-to-surface contact.

[0076] With the above steps completed, the assembly of the packaging box 10 containing the product is finished, and the packaging box 10 in the state shown in Figure 1 is completed.

[0077] Next, the operation and effects of the packaging box 10 of the first embodiment will be described with reference to Figures 1 and 3.

[0078] In the packaging box 10 of the first embodiment, the entire tip of the left inner flap 17L is superimposed on the outer surface of the right inner flap 17R. Therefore, even if there is a gap between the two leading edges of the pair of outer flaps 18, it is possible to eliminate the gap that communicates from the outside to the inside that occurs in the center of the closing portion 13. Thus, according to the packaging box 10 of the first embodiment, it is possible to suppress the intrusion of foreign matter into the packaging box 10.

[0079] Conversely, in the packaging box 10 of the first embodiment, the overlap of the inner flaps 17 can fill the gap between the pair of outer flaps 18. Therefore, even if the closing portion 13 has a vertically elongated shape, it is not necessary to make the outer flaps 18 longer and butt together, and they can be made shorter. Thus, according to the packaging box 10 of the first embodiment, the area of ​​the corrugated cardboard 10x can be reduced.

[0080] Incidentally, at the closing section 13 of the packaging box 10, a step is created when the left inner flap 17L overlaps the outer surface of the right inner flap 17R. As a result, the upper left inner flap 17L is more likely to come into contact with the outer flap 18, but the lower right inner flap 17R is pushed into the internal space of the packaging box 10 by the left inner flap 17L, making it less likely to come into contact with the outer flap 18.

[0081] However, since the outer flap 18 has a V-shaped fold line b and an outer flap valley fold line c, when folded along the fold line b, the central part in the width direction is bent so that it protrudes in a V-shape toward the internal space of the packaging box 10.

[0082] Therefore, in the packaging box 10, by folding the outer flap 18 along the outer flap fold line b and the outer flap valley fold line c, the outer flap 18 can be brought close not only to the upper left inner flap 17L but also to the lower right inner flap 17R.

[0083] Furthermore, in the packaging box 10, almost the entire inner surface of the left half 18L of the outer flap and almost the entire outer surface of the left inner flap 17L are in surface-to-surface contact, and almost the entire inner surface of the right half 18R of the outer flap and most of the outer surface of the right inner flap 17R (excluding the tip hidden by the left inner flap 17L) are in surface-to-surface contact.

[0084] Therefore, according to the packaging box 10 of the first embodiment, the left inner flap 17L and the right inner flap 17R and the outer flap 18 can be sufficiently pressed together with adhesive G, thus ensuring reliable assembly.

[0085] [Second Embodiment] The packaging box 20 according to the second embodiment of the present invention will be described below with reference to Figures 4 to 6. The packaging box 20 according to the second embodiment corresponds to the first packaging box and the third packaging box of the present invention described in the means for solving the problem.

[0086] As shown in Figure 4, the packaging box 20 of the second embodiment is a wrap-around case type with an external appearance formed in the shape of a rectangular parallelepiped. The packaging box 20 has a rectangular cylindrical body portion 22 that extends horizontally and a closing portion 23 that closes the open end of the body portion 22. When viewed from the closing portion 23 side, the packaging box 20 of the second embodiment is formed in a vertically elongated shape in which the height (length in the vertical direction) is longer than the width (length in the horizontal direction).

[0087] The body section 22 comprises a top plate 24, a bottom plate 25, and a pair of side plates 26. The pair of side plates 26 include the left side plate 26L on the rear (left) side in Figure 4 and the right side plate 26R on the front (right) side.

[0088] The closure section 23 comprises an inner flap 27 and a pair of outer flaps 28.

[0089] The pair of inner flaps 27 includes a left inner flap 27L connected to the left side plate 26L (corresponding to "one inner flap" in the present invention) and a right inner flap 27R connected to the right side plate 26R (corresponding to "the other inner flap" in the present invention). In Figure 4, the tip of the left inner flap 27L overlaps the outer surface of the right inner flap 27R.

[0090] A leaf-shaped connecting portion 27a is formed at the base end of the right inner flap 27R. The connecting portion 27a is bent at approximately 60° relative to the right side plate 26R, and bent at approximately 30° relative to the portion of the right inner flap 27R excluding the connecting portion 27a.

[0091] The pair of outer flaps 28 face each other with their leading edges separated by a predetermined distance.

[0092] Furthermore, the outer flap 28 is fixed to the outer surface of the inner flap 8 (left inner flap 27L and right inner flap 27R) via adhesive G.

[0093] The packaging box 20 is formed by punching out a roughly rectangular corrugated cardboard sheet 20x, as shown in Figure 5, from a base paper, and then folding and assembling it. The structure of the corrugated cardboard sheet 20x will be described below with reference to Figure 5.

[0094] As shown in Figure 5, the corrugated cardboard sheet 20x is arranged in the following order from left to right: left panel 26L, bottom panel 25, right panel 26R, top panel 24, and adhesive piece 29, each connected via a fold line e on the body. The top panel 24, bottom panel 25, left panel 26L, and right panel 26R are all formed in a roughly rectangular shape, while the adhesive piece 29 is formed in a roughly inverted trapezoidal shape.

[0095] The top plate 24 and the bottom plate 25 are connected to their upper and lower ends via outer flap fold lines f, respectively. Both outer flaps 28 are formed in a roughly rectangular shape. The combined length of a pair of outer flaps 28 from their base to their tip is designed to be smaller than the width (left-right direction in Figure 5) of the inner flaps 27 (left inner flap 27L and right inner flap 27R).

[0096] In Figure 5, the left inner flap 27L is attached to the upper and lower ends of the left inner flap plate 26L via the left inner flap fold line g. The left inner flap 27L is formed in a roughly rectangular shape.

[0097] The right inner flap 27R is connected to the upper and lower ends of the right inner flap plate 26R via the right inner flap fold line h. The right inner flap fold line h is formed in an arc shape that connects both corners on the base end side of the right inner flap 27R and bulges outward from the tip of the right inner flap 27R. In the second embodiment, the right inner flap fold line h is designed to have a radius of R500.

[0098] The right inner flap 27R has an inner flap mountain fold line i (corresponding to the "inner flap mountain fold line" of the third packaging box of the present invention, and also corresponding to the "approach fold line" of the first packaging box of the present invention) on the tip side of the right inner flap fold line h. The inner flap mountain fold line i is formed in an arc shape that connects both corners on the base end side of the right inner flap 27R and bulges in the direction approaching the tip of the right inner flap 27R. In the second embodiment, the inner flap mountain fold line i is designed to have a radius of R250.

[0099] The sum of the length from the base to the tip of the left inner flap 27L and the length from the base (right inner flap fold line h) to the tip of the left inner flap 27R is designed to be larger than the width of the top plate 24 and the bottom plate 25 (or outer flap 28).

[0100] Next, we will explain the procedure for assembling the packaging box 20 shown in Figure 4 from the corrugated cardboard 20x shown in Figure 5.

[0101] First, the worker places the corrugated cardboard sheets 20x on a table (not shown), for example, and then places multiple products (not shown) on the base plate 25 in an orderly fashion.

[0102] Next, in Figure 5, the left side plate 26L, which is located to the left of the base plate 25, is folded along the body fold line e and stands upright at a right angle to the base plate 25. Then, adhesive G (not shown) is applied to the outer surface of the upper end of the upright left side plate 26L.

[0103] Next, by sequentially folding along the fold line e located on the right side of the base plate 25, the right side plate 26R is raised perpendicular to the base plate 25, the top plate 24 is made parallel to the base plate 25, and the adhesive piece 29 hangs down. Then, the inner surface of the adhesive piece 29 is fixed to the outer surface of the left side plate 26L via adhesive G, thereby assembling the body 22.

[0104] Next, the right inner flap 27R is folded inward toward the body 22 at a right angle to the right side plate 26R along the right inner flap fold line h and the inner flap mountain fold line i.

[0105] More specifically, the right inner flap fold line h, provided at the base end of the right inner flap 27R, is formed in an arc shape that bulges away from the tip of the right inner flap 27R. Therefore, it does not bend on its own, but rather curves the right inner flap 27R toward the external space of the packaging box 20 along the width direction, while simultaneously curving the right inner flap 27R toward the internal space of the packaging box 20 along the width direction. As a result, the right inner flap 27R is folded approximately 60° relative to the right side plate 26R.

[0106] Next, the inner flap fold line i, which is located on the tip side of the right inner flap fold line h of the right inner flap 27R, is formed in an arc shape that bulges in the direction approaching the tip of the right inner flap 27R. By bending, it deforms a part of the base end of the right inner flap 27R into a leaf-shaped connecting portion 27a.

[0107] A portion of the right inner flap 27R at its base end (connecting portion 27a) is curved toward the internal space of the packaging box 20 when folded along the right inner flap fold line h. However, when folded along the right inner flap fold line h, which is formed in an arc shape that bulges toward the tip of the right inner flap 27R, it is returned to a flat state. On the other hand, the portion of the right inner flap 27R toward the tip of the connecting portion 27a is curved outward from the packaging box 20 along the width direction. As a result, the portion of the right inner flap 27R toward the tip of the connecting portion 27a is folded at approximately 30° relative to the connecting portion 27a.

[0108] As explained above, the right inner flap fold line h and the inner flap mountain fold line i do not bend naturally like a normal straight fold, but are allowed to bend slightly, absorbing the deformation caused by the bending in each part of the packaging box 20. However, since both ends of the right inner flap fold line h and the inner flap mountain fold line i are located at both corners on the base end side of the right inner flap 27R and connect these two corners, they fold sequentially simply by tilting the right inner flap 27R inward towards the body 22 with a little force.

[0109] Next, the left inner flap 27L is folded inward toward the body 22 at a right angle to the left side plate 26L along the left inner flap fold line g.

[0110] At this time, the sum of the length from the base to the tip of the left inner flap 27L and the length from the base to the tip of the left inner flap 27R is greater than the width of the top plate 24 and the bottom plate 25. Therefore, the tip of the left inner flap 27L overlaps the outer surface of the right inner flap 27R, as shown in Figure 6. As a result, in the closing portion 23 of the packaging box 20, the left inner flap 27L overlaps the outer surface of the right inner flap 27R, and the right inner flap 27R is pushed into the internal space of the packaging box 20, creating a step.

[0111] Next, as shown in Figure 4, adhesive G is applied to the outer surfaces of the left inner flap 27L and the right inner flap 27R at the positions where the outer flap 28 will overlap.

[0112] Next, as shown in Figure 4, the lower outer flap 28 is folded upward along the outer flap fold line f, and the inner surface of the lower outer flap 28 is fixed to the outer surface of the inner flap 7 (left inner flap 27L and right inner flap 27R) via adhesive G. The upper outer flap 28 is folded downward along the outer flap fold line f, and the inner surface of the upper outer flap 28 is fixed to the outer surface of the inner flap 7 (left inner flap 27L and right inner flap 27R) via adhesive G.

[0113] At this time, the sum of the lengths from the base end to the tip of the pair of outer flaps 28 is designed to be smaller than the width (vertical direction in Figure 4) of the inner flaps 27 (left inner flap 27L and right inner flap 27R), so the tip edges of the pair of outer flaps 28 face each other with a predetermined distance between them. As a result, the open end of the body portion 22 is closed, and the closed portion 23 is formed. With the above steps completed, the assembly of the packaging box 20 containing the product is finished, and the packaging box 20 in the state shown in Figure 4 is completed.

[0114] Next, the operation and effects of the packaging box 20 of the second embodiment will be described with reference to Figures 4 and 6.

[0115] As shown in Figure 4, in the packaging box 20 of the second embodiment, the entire tip of the left inner flap 27L is superimposed on the outer surface of the right inner flap 27R. Therefore, even if there is a gap between the two leading edges of the pair of outer flaps 28, the gap that communicates from the outside to the inside that occurs in the center of the closing portion 23 can be eliminated. Thus, according to the packaging box 20 of the second embodiment, the intrusion of foreign matter into the packaging box 20 can be suppressed.

[0116] Conversely, in the packaging box 20 of the second embodiment, the overlap of the inner flaps 27 can fill the gap between the pair of outer flaps 28. Therefore, even if the closing portion 23 has a vertically elongated shape, it is not necessary to make the outer flaps 28 longer and butt together, and they can be made shorter. Thus, according to the packaging box 20 of the second embodiment, the area of ​​the corrugated cardboard 20x can be reduced.

[0117] Incidentally, at the closing section 23 of the packaging box 20, a step is created when the left inner flap 27L overlaps the outer surface of the right inner flap 27R. As a result, the upper left inner flap 27L is more likely to come into contact with the outer flap 28, but the lower right inner flap 27R is pushed into the internal space of the packaging box 20 by the left inner flap 27L, making it less likely to come into contact with the outer flap 28.

[0118] However, the bending of the right inner flap 27R along the right inner flap fold line h and the inner flap mountain fold line i is absorbed and tolerated by various parts of the packaging box 20, resulting in a strong restoring force that tries to return it to its original state (position along the body 22). Therefore, even when the outer surface of the tip of the right inner flap 27R is pressed against the left inner flap 27L, the aforementioned restoring force causes the entire flap, except for the tip, to repel and try to protrude outward from the packaging box 20.

[0119] Furthermore, as shown in Figure 6, the connecting portion 27a of the right inner flap 27R is inclined with respect to both the right inner flap 27R and the outer flap 28, and the left edge of the connecting portion 27a (inner flap fold line i) is arranged in a convex shape that points outward from the packaging box 20. As a result, even if the tip of the right inner flap 27R is pushed inward into the internal space of the packaging box 20, the portion along the inner flap fold line i can be made to protrude outward into the external space of the packaging box 20 as a ridge, bringing it closer to the outer flap 18.

[0120] Therefore, in the packaging box 20 of the second embodiment, when attempting to press the outer flap 28 toward the internal space of the packaging box 20 and press it with adhesive G, the right inner flap 27R repels the portion along the inner flap fold line i as a ridge, making it easier to adhere the right inner flap 27R to the outer flap 28 along the portion along the inner flap fold line i.

[0121] Therefore, according to the packaging box 20 of the second embodiment, not only the left inner flap 27L but also the right inner flap 27R can be sufficiently pressed against the outer flap 28 with adhesive G, thus ensuring reliable assembly.

[0122] [Third Embodiment] Hereinafter, a packaging box 30 (not shown) according to the third embodiment of the present invention will be described with reference to Figures 7 and 8. The packaging box 30 according to the third embodiment corresponds to the first packaging box and the third packaging box of the present invention described in the means for solving the problem.

[0123] Furthermore, the packaging box 30 is one of the modified forms of the packaging box 20 of the second embodiment, and differs from the packaging box 20 in the shape of the right side panel and the right inner flap. Therefore, only this point will be explained, and the configuration common to the packaging box 20 will not be explained.

[0124] A rectangular connecting portion 37a is formed at the base end of the right inner flap 37R. The connecting portion 37a is bent at a right angle to the right side plate 36R and bent at approximately 5° relative to the portion of the right inner flap 37R excluding the connecting portion 37a.

[0125] The packaging box 30 is formed by punching out a roughly rectangular corrugated cardboard sheet 30x, as shown in Figure 7, from a base sheet, and then folding and assembling it. The right side panel 36R has right inner flaps 37R connected to its upper and lower ends via a straight right inner flap fold line h'. The right side panel 36R is formed in a roughly rectangular shape.

[0126] The right inner flap 37R has a straight inner flap mountain fold line i' (corresponding to the "inner flap mountain fold line" of the third packaging box of the present invention, and also corresponding to the "proximity fold line" of the first packaging box of the present invention) on the tip side of the right inner flap fold line h'. The inner flap mountain fold line i' is formed parallel to the right inner flap fold line h' by connecting the middle portions of both side edges of the right inner flap 37R.

[0127] Next, we will explain the procedure for assembling the packaging box 30 from the corrugated cardboard 30x shown in Figure 7, including the closing section 33.

[0128] Next, the right inner flap 37R is folded inward toward the body 32 at a right angle to the right side plate 36R along the right inner flap fold line h'. Furthermore, while maintaining the angle of the connecting portion 37a provided at the base end of the right inner flap 37R, the part of the right inner flap 37R beyond the connecting portion 37a is folded inward toward the internal space of the body 32 at approximately 5° relative to the connecting portion 37a along the inner flap mountain fold line i'.

[0129] Next, the left inner flap 37L is folded inward toward the body 32 at a right angle to the left side plate 36L along the left inner flap fold line g.

[0130] At this time, the sum of the length from the base end to the tip of the left inner flap 37L and the length from the base end to the tip of the left inner flap 37R is greater than the width of the top plate 34 and the bottom plate 35. Therefore, the tip of the left inner flap 37L overlaps with the outer surface of the right inner flap 37R, as shown in Figure 6. As a result, in the closing portion 33 of the packaging box 30, the left inner flap 37L overlaps with the outer surface of the right inner flap 37R, and the tip side of the right inner flap 37R beyond the connection portion 37a is pushed into the internal space of the packaging box 30, creating a step.

[0131] Next, adhesive G is applied to the outer surfaces of the left inner flap 37L and the right inner flap 37R at the positions where the outer flaps 38 overlap. The lower outer flap 38 is folded upward along the outer flap fold line f, and the inner surface of the lower outer flap 38 is fixed to the outer surface of the inner flap 7 (connecting portion 37a of the left inner flap 37L and the right inner flap 37R) via adhesive G. The upper outer flap 38 is folded downward along the outer flap fold line f, and the inner surface of the upper outer flap 38 is fixed to the outer surface of the inner flap 7 (connecting portion 37a of the left inner flap 37L and the right inner flap 37R) via adhesive G.

[0132] As a result, the open end of the body portion 32 is closed, and the closed portion 33 is formed. With this, the assembly of the packaging box 30 containing the product is completed, and the packaging box 30 in the state shown in Figure 4 is completed.

[0133] Next, with reference to Figure 8, we will explain the functions and effects of the packaging box 30 of the third embodiment, specifically the aspects of the packaging box 20.

[0134] As shown in Figure 8, at the closing portion 33 of the packaging box 30, a step is created when the left inner flap 37L overlaps the outer surface of the tip of the right inner flap 37R. As a result, the upper left inner flap 37L is more likely to come into contact with the outer flap 38, but the lower right inner flap 37R is pushed into the internal space of the packaging box 30 by the left inner flap 37L, making it less likely to come into contact with the outer flap 38.

[0135] However, by folding the right inner flap 37R along the inner flap mountain fold line i', the portion of the connecting part 37a remains on the same plane as the left inner flap 37L, while only the portion of the connecting part 37a toward the interior space of the packaging box 30 is pushed inward. In other words, even if the leading edge of the right inner flap 37R is pushed inward toward the interior space of the packaging box 30 by the left inner flap 37L, the portion along the inner flap mountain fold line i' is displaced toward the exterior space of the packaging box 30 as a ridge, bringing the entire portion of the connecting part 37a closer to the outer flap 18.

[0136] Furthermore, since both the right inner flap fold line h' and the inner flap mountain fold line i' are straight, when the connecting portion 37a is folded along the right inner flap fold line h' and the inner flap mountain fold line i', it remains flat and is positioned on the same plane as the left inner flap 37L without curving.

[0137] As a result, the right inner flap 37R can be bonded surface-to-surface with the outer flap 18 at the connection portion 37a.

[0138] Therefore, according to the packaging box 30 of the third embodiment, not only the left inner flap 37L but also the right inner flap 37R can be sufficiently pressed against the outer flap 38 with adhesive G, thus ensuring reliable assembly.

[0139] [Modifications common to each embodiment] In the embodiments described above, corrugated cardboard was used as an example of the material, but the material may be cardboard or a thin synthetic resin sheet, as long as it can be folded and assembled and can be broken along the breakable line. Also, in the embodiments described above, adhesive was used as an example of the means of fixing, but staples or adhesive tape may also be used as the means of fixing.

[0140] In the first embodiment, the approach fold line of the present invention was described using as an example the V-shaped outer flap fold line b provided on the outer flap 18, and in the second embodiment, the inner flap mountain fold line i provided on the inner flap 17 (right inner flap 17R) (in the third embodiment, the inner flap mountain fold line i' provided on the inner flap 27 (right inner flap 27R)) as an example. However, the approach fold line of the present invention may be provided on either the inner flap or the outer flap, as long as it brings the other inner flap, which is separated from the outer flap by a step, closer together.

[0141] In each of the above embodiments, the left inner flap was described as being superimposed on the outer surface of the right inner flap, There are no restrictions on left or right; the right inner flap may be placed over the outer surface of the left inner flap.

[0142] In the embodiments described above, the tip of the left inner flap was described as overlapping the outer surface of the tip of the right inner flap. However, if at least a portion of the right inner flap is exposed to the closure side and can adhere to the outer flap, more than half of the portion excluding the base end may be overlapped.

[0143] In the embodiments described above, the entire tip of the left inner flap was described as overlapping the entire outer surface of the tip of the right inner flap. However, the left inner flap and the right inner flap may overlap only in a portion of their respective tips, as long as they are positioned to fill the gap between the tip edges of at least one pair of outer flaps.

[0144] In the embodiments described above, the inner and outer flaps were described as being formed in a substantially rectangular shape, but the inner and outer flaps may also be polygonal in shape, such as trapezoidal or triangular, or semicircular.

[0145] [Modified version of the first embodiment] In the first embodiment described above, the outer flap fold line b was described as being formed in a V-shape that protrudes toward the body portion 12 side from the extension of the inner flap fold line d. However, the outer flap fold line b may have multiple bends or curve in an arc shape, as long as it connects both corners on the base end side of the outer flap 18 and is formed in a convex shape away from the tip of the outer flap 18. Furthermore, the outer flap fold line b may have a bend 18a, but the outer flap left fold line b1 and the outer flap right fold line b2 may not be straight lines, but rather formed in separate arc shapes.

[0146] In the first embodiment described above, the left-turn line b1 of the outer flap was described as being longer than the right-turn line b2 of the outer flap. However, the left-turn line b1 of the outer flap may be the same length as the right-turn line b2 of the outer flap, or even shorter.

[0147] In the first embodiment described above, the outer flap valley fold line c was explained as extending along the body fold line a from the bent portion 18a of the outer flap 18 to the middle of its leading edge. However, the outer flap valley fold line c may be connected to the outer flap fold line b at a location other than the bent portion, for example, since the outer flap fold line b may be arc-shaped and not have a bent portion. Furthermore, it is sufficient that the outer flap 18 can be made convex toward the internal space of the packaging box 1, so it may be provided only in the central part of the outer flap 18 and not connected to the outer flap fold line b or the leading edge of the outer flap 18.

[0148] Furthermore, although the first embodiment described above used an example where one outer flap valley fold line c was provided on the outer flap 18, multiple outer flap valley fold lines c may be provided, and these multiple lines may be provided parallel to the body fold line a, or they may be provided radially from the center of the tip edge of the outer flap 18.

[0149] In the first embodiment described above, the inner surface of the left half 18L of the outer flap 18 and the outer surface of the left inner flap 17L are in surface-to-surface contact, and the inner surface of the right half 18R of the outer flap 18 and the outer surface of the right inner flap 17R are in surface-to-surface contact. However, the outer flap 18 may also be bonded to the outer surfaces of the left inner flap 17L and the right inner flap 17R by line contact or point contact.

[0150] [Modifications of the second and third embodiments] In the second and third embodiments described above, a leaf-shaped connecting portion 27a and a rectangular connecting portion 37a were used as examples, but the connecting portion may also be triangular, pentagonal, hexagonal, or the like.

[0151] In the second embodiment described above, the right inner flap fold line h was described as being formed in an arc shape that bulges in a direction away from the tip of the right inner flap 27R. However, as described in the third embodiment described above, the right inner flap fold line may be straight, or a straight section may be connected by multiple bent sections.

[0152] In the second embodiment described above, the inner flap fold line i was described as an arc that bulges in the direction approaching the tip of the right inner flap 27R. However, as described in the third embodiment above, the inner flap fold line i may be straight, or a straight section may be connected by multiple bends. In addition, in the second embodiment, only one of the right inner flap fold line h and the inner flap fold line i may be straight.

[0153] In the second and third embodiments described above, the example described was one in which a single inner flap fold line i is provided on the right inner flap, but multiple inner flap fold lines i may be provided.

[0154] In the second embodiment, the right inner flap fold line h is designed to have a radius of R500, and the inner flap peak fold line i is designed to have a radius of R250. However, there are no limitations on the radius of curvature, and the radii of curvature of the right inner flap fold line h and the inner flap peak fold line i may be equal, or the radius of curvature of the inner flap peak fold line i may be larger. [Explanation of Symbols]

[0155] 10 packaging box 12 Torso 13 Occlusion 14 Top plate 15 Bottom plate 16 Side wall panels 17 Inner flap 17L Left Inner Flap 17R Right inner flap 18 Outer flap 18a Bend part 20 packaging box 22 Torso 23 Occlusion 24 Top plate 25 Bottom plate 26 Side wall panels 27 Inner flap 27L Left interior flap 27R Right inner flap 28 Outer flap 30 packaging box 32 Torso 33 Occlusion 34 Top plate 35 Bottom plate 36 Side wall panels 37 Inner flap 37L Left Inner Flap 37R Right inner flap 38 Outer flap a. Fold line on the body b. Outer flap fold line (approach fold line) b1 Outer flap left turn line (straight section) b2 Outer flap right turn line (straight section) c Outer flap valley fold line d. Inner flap fold line e. Fold line on the body f Outer flap fold line g Inner flap fold line h Inner flap fold line h' Inner flap fold line i. Inner flap fold line (approach fold line) i' Inner flap mountain fold line (approach fold line)

Claims

1. A packaging box having a rectangular cylindrical body and a pair of closing parts that close the open ends of the body, The body is constructed by connecting a top plate, a bottom plate, and a pair of side wall plates via a fold line in the body. The closing portion comprises a pair of inner flaps connected to the pair of side wall plates via inner flap fold lines, and a pair of outer flaps connected to the top plate and the bottom plate via outer flap fold lines and fixed to the outer surface of the inner flaps. The pair of outer flaps are arranged so that their leading edges face each other with a predetermined distance between them. The tip of one inner flap overlaps the outer surface of the other inner flap in the region where it is sandwiched between the tip edges of at least one pair of outer flaps. A packaging box characterized in that the outer flap or the other inner flap has a fold line that causes it to bend itself to bring it closer to the other.

2. A packaging box having a rectangular cylindrical body and a pair of closing parts that close the open ends of the body, The body is constructed by connecting a top plate, a bottom plate, and a pair of side wall plates via a fold line in the body. The closing portion comprises a pair of inner flaps connected to the pair of side wall plates via inner flap fold lines, and a pair of outer flaps connected to the top plate and the bottom plate via outer flap fold lines and fixed to the outer surface of the inner flaps. The pair of outer flaps are arranged so that their leading edges face each other with a predetermined distance between them. The tip of one inner flap overlaps the outer surface of the other inner flap in the region where it is sandwiched between the tip edges of at least one pair of outer flaps. The packaging box is characterized in that the outer flap fold line connects both corners on the base end side of the outer flap and is formed in a convex shape in a direction away from the tip of the outer flap.

3. In the packaging box according to claim 2, The aforementioned outer flap fold line is formed in a V-shape, where two straight sections are connected by a bent section. The packaging box is characterized in that the outer flap has an outer flap valley fold line that extends from the bent portion to the middle of the leading edge of the outer flap.

4. In the packaging box according to claim 3, A packaging box characterized in that the distance from the outer flap's valley fold line to the base end of one of the inner flaps is equal to or greater than the distance from the base end to the tip of one of the inner flaps.

5. A packaging box having a rectangular cylindrical body and a pair of closing parts that close the open ends of the body, The body is constructed by connecting a top plate, a bottom plate, and a pair of side wall plates via a fold line in the body. The closing portion comprises a pair of inner flaps connected to the pair of side wall plates via inner flap fold lines, and a pair of outer flaps connected to the top plate and the bottom plate via outer flap fold lines and fixed to the outer surface of the inner flaps. The pair of outer flaps are arranged so that their leading edges face each other with a predetermined distance between them. The tip of one inner flap overlaps the outer surface of the other inner flap in the region where it is sandwiched between the tip edges of at least one pair of outer flaps. The packaging box is characterized in that the other inner flap has an inner flap mountain fold line that connects both side edges of the other inner flap, located on the tip side of the inner flap fold line.

6. In the packaging box according to claim 5, The inner flap fold line provided along the base end of the other inner flap is formed in an arc shape that connects both corners on the base end side of the other inner flap and bulges in a direction away from the tip of the other inner flap. The packaging box is characterized in that the inner flap fold line is formed in an arc shape that connects both corners on the base end side of the other inner flap and bulges out in a direction approaching the tip of the other inner flap.

7. In the packaging box according to claim 5, The inner flap fold line provided along the base end of the other inner flap is formed in a straight line so as to be paired with the inner flap fold line provided along the base end of the first inner flap. The packaging box is characterized in that the inner flap fold line is formed in a straight line by connecting the middle portions of both side edges of the other inner flap.

Images