JP7021830B2 - Packaging box - Google Patents

Description

The present invention relates to a packaging box.

Packaging boxes that are not easily deformed by a compressive load are known.

For example, the stepped packaging box described in Patent Document 1 is a so-called A-type box having a pair of end plates, a pair of side plates, four inner flaps on the upper and lower sides, and four outer flaps on the upper and lower sides. be. The side plate is formed wider than the end plate. An edge ruled line is formed at the boundary between the pair of end plates and the inner flap, and a side ruled line is formed at the boundary between the pair of side plates and the outer flap. The side ruled line is divided into both end portions and a central portion located between them. Both end portions are formed at positions shifted outward in the vertical direction from the end ruled line, and the central portion is formed at positions shifted inward in the vertical direction from both end portions. Since the central portion of the side ruled line is located inside the both end portions, the heights of the side plates and the end plates are substantially uniform, and the balance of the load applied to the side plates and the end plates when the packaging boxes are stacked is improved.

Japanese Unexamined Patent Publication No. 2015-40048

By the way, the wider the corrugated cardboard sheet or the like (the larger the area), the lower the rigidity (compressive strength), and the easier it is to bend. In the above-mentioned stepped packaging box, the heights of the side plates and the end plates are simply aligned, and substantially the same compressive load is applied to the side plates and the end plates without considering the difference in width (area) between the side plates and the end plates. It was like that. For this reason, the wide side plate may start to buckle before the narrow end wall. That is, there is a possibility that the above-mentioned stepped packaging box cannot withstand a large compressive load.

In order to solve the above problems, the present invention provides a packaging box capable of suppressing deformation due to a compressive load.

In order to achieve the above object, the packaging box of the present invention has a pair of side walls facing in the first direction and a pair of side walls facing each other in the second direction having higher compressive strength than the side walls. The end wall of the wall, the first upper flap connected to the upper end of the side wall via the first upper fold curve, and the upper end of the end wall connected to the upper end of the end wall via the second upper fold curve. A second upper flap, a first lower flap connected to the lower end of the side wall via a first lower fold curve, and a second lower flap connected to the lower end of the end wall via a second lower fold curve. A second lower flap is provided, and at least one of the first upper fold curve and the first lower fold curve is formed so as to be recessed toward the center of the side wall, and is formed with the second upper fold curve. At least one of the second lower bend curves is formed so as to protrude in a direction away from the center of the end wall.

In addition, in order to achieve the above object, the packaging box of the present invention has a pair of side walls facing the first direction, a pair of end walls facing the second direction intersecting the first direction, and the side wall. A first upper flap connected to the upper end of the end wall via a first upper fold curve, a second upper flap connected to the upper end of the end wall via a second upper fold curve, and the above. A first lower flap connected to the lower end of the side wall via a first lower fold curve, and a second lower flap connected to the lower end of the end wall via a second lower fold curve. The first upper fold curve and at least one of the first lower fold curve are formed so as to be recessed toward the center of the side wall, and the second upper fold curve and the second lower fold curve are formed. At least one of them is formed so as to be recessed toward the center of the end wall.

In this case, it is preferable that the end wall is formed with an opening or a cutting line that reduces the compressive strength of the end wall.

In this case, it is preferable that the end wall is formed narrower than the side wall.

In this case, at least one of the first upper fold curve, the first lower fold curve, the second upper fold curve, and the second lower fold curve is bent in a V shape or curved in an arc shape. It is preferable that it is formed in such a state.

In this case, at least one of the first upper fold curve, the first lower fold curve, the second upper fold curve, and the second lower fold curve is a pair of inclinations inclined in an arc shape or a straight line. It preferably includes an intermediate portion that connects the ends in a straight line.

In this case, four square walls provided between the side wall and the end wall are further provided, and the pair of side walls, the pair of end walls and the four square walls form an octagonal columnar peripheral wall, and the said. The second upper flap is preferably arranged so as to overlap the surface of the first upper flap folded inside the peripheral wall.

According to the present invention, deformation of the packaging box due to a compressive load can be suppressed.

It is a perspective view which shows the packaging box which concerns on 1st Embodiment of this invention. It is a top view which shows the blank of the packaging box which concerns on 1st Embodiment of this invention. FIG. 3 is an enlarged plan view showing a part of a blank of a packaging box according to the first embodiment of the present invention. It is a perspective view explaining the distribution of the compressive load when the packaging boxes which concern on 1st Embodiment of this invention are stacked. FIG. 3 is an enlarged plan view showing a part of a blank of a packaging box according to a modified example of the first embodiment of the present invention. FIG. 3 is an enlarged plan view showing a part of a blank of a packaging box according to another modification of the first embodiment of the present invention. FIG. 3 is an enlarged plan view showing a part of a blank of a packaging box according to another modification of the first embodiment of the present invention. It is a top view which shows the blank of the packaging box which concerns on 2nd Embodiment of this invention. It is a perspective view explaining the distribution of the compressive load when the packaging boxes which concern on 2nd Embodiment of this invention are stacked. It is a top view which shows the blank of the packaging box which concerns on 3rd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the drawing, "Fr" indicates "front", "Rr" indicates "rear", "L" indicates "left", "R" indicates "right", and "U" indicates "U". "Upper" and "D" indicate "lower". The front-back direction (first direction) is orthogonal (crosses) to the left-right direction (second direction), and the up-down direction is orthogonal (crosses) to the front-back direction and the left-right direction. Although terms indicating directions and positions are used in the present specification, these terms are used for convenience of explanation and do not limit the technical scope of the present invention.

[First Embodiment]
The packaging box 1 according to the first embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is a perspective view showing a packaging box 1. FIG. 2 is a plan view showing the blank 5 of the packaging box 1. FIG. 3 is an enlarged plan view showing a part of the blank 5.

[Overview of packaging box]
As shown in FIG. 1, the packaging box 1 is formed in a substantially octagonal columnar shape. The packaging box 1 is sealed by closing the upper surface and the lower surface of the peripheral wall 1W having a substantially octagonal cross section. The contents (not shown) are accommodated inside the packaging box 1.

The packaging box 1 is formed by assembling the blank 5 shown in FIG. The blank 5 is formed by punching, for example, a sheet of paper corrugated cardboard with a die or the like. The corrugated cardboard sheet is, for example, a double-sided corrugated cardboard sheet in which a front liner 9B and a back liner 9C (see FIG. 1) are bonded to the front and back of a corrugated cardboard 9A. Note that FIG. 2 shows the front liner 9B side (outer surface of the packaging box 1). In the present specification, the direction parallel to the corrugated cardboard sheet 9A is referred to as "step direction", and the direction orthogonal to the step direction is referred to as "flow direction". “X” shown in the drawing indicates “step direction”, and “Y” indicates “flow direction”. Further, in the present specification, the terms "top (heaven)", "bottom (bottom)" and similar terms are the top (heaven), bottom (bottom) and the like in the assembled state (use state) of the packaging box 1. Refers to a concept similar to.

[blank]
As shown in FIG. 2, the blank 5 includes a pair of side walls 10 and 11, a pair of end walls 12 and 13, four square walls 14, 15, 16 and 17, and a pair of joint pieces 18. It includes one upper flap 20, 21, a pair of second upper flaps 22, 23, a pair of first lower flaps 30, 31 and a pair of second lower flaps 32, 33.

<Walls, end walls>
The pair of side walls 10 and 11 and the pair of end walls 12 and 13 are alternately connected to each other via three square walls 15 to 17. The side walls 10, 11, the end walls 12, 13 and the square walls 14 to 17 are formed in a substantially rectangular shape having substantially the same dimensions in the step direction. The side walls 10 and 11 are formed in a substantially rectangular shape long in the flow direction. Since the end walls 12 and 13 are formed to be narrower in the flow direction than the side walls 10 and 11, they are formed in a substantially rectangular shape that is long in the step direction as a whole.

<Square wall, joint piece>
The three square walls 15 to 17 are connected to the side walls 10 and 11 and the end walls 12 and 13 via a vertical folding curve L1 extending in the step direction. One square wall 14 is continuously provided at the flow direction end portion of the side wall 10 via the vertical folding curve L1. The four square walls 14 to 17 are formed in a substantially rectangular shape elongated in the step direction. One square wall 14 is formed to be narrower in the flow direction than the other three square walls 15 to 17. The joint piece 18 is continuously provided at the end portion of the end wall 13 in the flow direction via the vertical folding curve L1. The joint piece 18 is formed in substantially the same shape as the square wall 14. The pair of side walls 10, 11, the pair of end walls 12, 13 and the four square walls 14 to 17 are folded along the vertical folding curve L1 to form a peripheral wall 1W having a substantially octagonal cylindrical shape. ..

<1st upper flap, 2nd upper flap>
The pair of first upper flaps 20 and 21 are connected to one end portion (upper end portion) of the side walls 10 and 11 in the step direction via the first upper folding curve L2. The first upper flaps 20 and 21 are formed in an irregular shape such that both ends of a rectangle in the flow direction protrude outward. In other words, the first upper flaps 20 and 21 are formed in a shape corresponding to approximately half of the octagonal cross section of the peripheral wall 1W (see FIG. 1). The pair of second upper flaps 22 and 23 are connected to one end of the end walls 12 and 13 in the step direction via the second upper folding curve L3. The second upper flaps 22 and 23 are formed in a substantially trapezoidal shape that gradually narrows in width from the root portion (side of the end walls 12 and 13) toward the tip. The dimension (extended dimension) of the second upper flaps 22 and 23 in the step direction is set shorter than the extended dimension of the first upper flaps 20 and 21.

<1st lower flap, 2nd lower flap>
The pair of first lower flaps 30, 31 are connected to the other end (lower end) of the side walls 10 and 11 in the step direction via the first lower folding curve L4. The first lower flaps 30 and 31 have an irregular shape such that both ends of the rectangle project outward in the flow direction, and are formed in a shape corresponding to approximately half of the octagonal cross section of the peripheral wall 1W (see FIG. 1). ). The tips of the first lower flaps 30 and 31 are larger than the tips of the first upper flaps 20 and 21. The pair of second lower flaps 32, 33 are connected to the other end of the end walls 12, 13 in the step direction via the second lower folding curve L5. The second lower flaps 32 and 33 are formed in a substantially rectangular shape. The dimensions (extended dimensions) of the second lower flaps 32 and 33 in the step direction are set to be substantially the same as the extended dimensions of the first lower flaps 30 and 31.

The vertical fold curve L1, the first upper fold curve L2, the second upper fold curve L3, the first lower fold curve L4, and the second lower fold curve L5 make the corrugated cardboard sheet linear in the thickness direction from the back liner 9C side. It is a general-purpose ruled line formed by crushing. Each folding curve L1 to L5 has a function of bending the corrugated cardboard sheet so that the back liner 9C faces inward. The folding curves L1 to L5 are not limited to general-purpose ruled lines, and for example, lead ruled lines in which a plurality of cuts are arranged at equal intervals on the general-purpose ruled lines may be adopted.

<1st upper turn curve, 1st lower turn curve>
As shown in FIG. 2, the pair of first upper fold curves L2 and the pair of first lower fold curves L4 are formed so as to be recessed toward the center of the side walls 10 and 11. Specifically, the first upper turn curve L2 is inclined downward from both ends in the flow direction toward the center, and the first lower turn curve L4 is inclined upward from both ends in the flow direction toward the center. That is, the first upper fold curve L2 and the first lower fold curve L4 are formed in a state of being bent in a substantially V shape so as to protrude from each other toward the central portion of the side walls 10 and 11. The first upper fold curve L2 and the first lower fold curve L4 have shapes that are substantially symmetrical with the side walls 10 and 11 interposed therebetween.

As shown in FIG. 3, when the line connecting both ends of the root portion of the first upper flap 20 or the like in the flow direction is a virtual line V1 parallel to the flow direction, the first upper turn curve L2 is the virtual line V1. It is inclined so that the maximum value of the distance from and is about 1 to 2 mm. Similarly, when the virtual line V2 is formed by connecting both ends of the root portion of the first lower flap 30 or the like in the flow direction, the maximum value of the distance between the first lower turn curve L4 and the virtual line V2 is 1 to 1. It is tilted to about 2 mm.

<Second upper turn curve, second lower turn curve>
As shown in FIG. 2, the pair of second upper folding curves L3 are formed at positions slightly offset to the side of the second upper flaps 22 and 23 from the extension line of the virtual line V1. The pair of second upper folding curves L3 are formed substantially parallel to the virtual line V1 (see FIG. 3). The second lower folding curve L5 is formed so as to protrude in a direction away from the center of the end walls 12 and 13. Specifically, the second lower turn curve L5 is inclined downward from both ends in the flow direction toward the center, and is formed in a state of being bent in a substantially V shape. As shown in FIG. 3, the second lower turn curve L5 is inclined so that the maximum value of the distance from the extension line of the virtual line V2 is about 1 to 2 mm.

In the drawings, the inclination angle and the degree of bending are emphasized in order to make it easy to understand that the first upper turn curve L2, the first lower turn curve L4, and the second lower turn curve L5 are bent.

As shown in FIG. 2, the blank 5 is provided with a cut tape 40 over the entire flow direction. The cut tape 40 is made of a synthetic resin (polypropylene or the like) having high tensile strength, and is attached to the back liner 9C of the blank 5 with an adhesive. The cut tape 40 is provided so as to cross the side walls 10, 11, the end walls 12, 13, the square walls 14 to 17, and the joint piece 18 in the flow direction. The cut tape 40 is located on the side of the first lower flaps 30 and 31 with respect to the center of the side walls 10, 11 and the like in the step direction. The cut tape 40 has a function of cutting a corrugated cardboard sheet. The cut tape 40 may be omitted. Further, the cut tape 40 is not limited, and for example, a half cut, a sewing machine blade wire, or the like may be adopted.

A pair of knob lines 41 are formed at both ends of the side wall 11 in the flow direction so as to cut the cut tape 40. The pair of picking lines 41 are cut inward from the vertical folding curves L1 on both sides of the side wall 11 in a substantially U-shape (horizontal substantially U-shape).

Further, a pair of side surface zippers 42 are formed at both ends of the side wall 11 in the flow direction, and a pair of top surface zippers 43 are formed on the first upper flap 21 connected to the side wall 11. The pair of side surface zippers 42 are formed along the vertical folding curves L1 on both sides of the side wall 11. The pair of top zipper 43s are continuous with the pair of side zipper 42, and extend diagonally from the root portion of the first upper flap 21 toward the tip thereof so as to approach each other. The side zipper 42 and the top zipper 43 have a function of cutting the side wall 11 and the first upper flap 21. The side zipper 42 and the top zipper 43 may be omitted. Further, the side zipper 42 and the top zipper 43 are not limited, and for example, a half cut, a sewing machine blade wire, or the like may be adopted.

[Assembly of packaging box]
Next, the assembly work of the packaging box 1 will be described with reference to FIG. The packaging box 1 may be manually assembled by an operator, or may be automatically or semi-automatically assembled by a box making machine. Here, as an example, a case where an operator assembles the packaging box 1 will be described. Further, it is assumed that the joint piece 18 is in a state of being adhered to the inner surface of the square wall 14 via an adhesive. As the adhesive, for example, a hot melt adhesive, a synthetic resin emulsion adhesive, a double-sided tape, or the like can be used.

The operator bends the pair of side walls 10, 11, the pair of end walls 12, 13 and the four square walls 14 to 17 along the vertical folding curve L1 to form a substantially octagonal square tube shape. In this state, the pair of side walls 10 and 11 are arranged to face each other in the front-rear direction (first direction), and the pair of end walls 12 and 13 face each other in the left-right direction (second direction intersecting the first direction). Be placed. The four square walls 14 to 17 are provided between the side walls 10 and 11 and the end walls 12 and 13 in a posture of intersecting the side walls 10 and 11 and the end walls 12 and 13. As described above, the vertical folding curve L1 of the pair of side walls 10, 11, the pair of end walls 12, 13 and the four square walls 14 to 17 forms a substantially octagonal columnar peripheral wall 1W with both upper and lower sides open.

Next, the operator bends the pair of second lower flaps 32, 33 inward along the second lower folding curve L5. Subsequently, the operator applies an adhesive to the front liner 9B of the second lower flaps 32 and 33 (or the back liner 9C of the first lower flaps 30 and 31), and applies the pair of first lower flaps 30 and 31 to the first. 1 Bend inward along the lower fold curve L4. The pair of first lower flaps 30 and 31 are adhered to the pair of second lower flaps 32 and 33 via an adhesive, and the tips thereof are abutted to close the lower surface of the peripheral wall 1W. In this state, the bottom surface of the packaging box 1 is formed.

The operator puts the contents inside through the upper surface opening of the peripheral wall 1W and places them on the lower flaps 30 to 33 which are the bottom surfaces of the packaging box 1.

Next, the operator bends the pair of first upper flaps 20, 21 inward along the first upper folding curve L2. The pair of first upper flaps 20, 21 abut their tip portions to close the upper surface of the peripheral wall 1W. Subsequently, the operator applies an adhesive to the front liner 9B of the first upper flaps 20 and 21 (or the back liner 9C of the second upper flaps 22 and 23), and applies the pair of second upper flaps 22 and 23 to the first. 2 Bend inward along the upper fold curve L3. The pair of second upper flaps 22 and 23 are adhered to the pair of first upper flaps 20 and 21 via an adhesive. In this state, the second upper flaps 22 and 23 are arranged so as to overlap the surfaces of the first upper flaps 20 and 21 folded inside the peripheral wall 1W, and the top surface of the packaging box 1 is formed.

As a result, the assembly work of the packaging box 1 is completed (see FIG. 1). That is, the packaging box 1 is in a sealed state (see FIG. 1).

Here, the opening work of the packaging box 1 will be briefly described. The operator grasps the one portion formed by raising the portion surrounded by the picking line 41 toward the front and pulls it in the horizontal direction, and cuts the side wall 11 along the cut tape 40. After that, the operator grasps the lower part of the side wall 11 cut by the cut tape 40 and pulls it upward, cuts the side wall 11 along the pair of side surface zippers 42, and cuts the first upper flap 21 with the pair of top surface zippers. Cut along 43. As described above, the packaging box 1 is opened, and the contents can be taken out from the opening formed from the front surface to the upper surface. The packaging box 1 may be opened by cutting the entire circumference of the peripheral wall 1W along the cut tape 40 and dividing the peripheral wall 1W into upper and lower parts. Alternatively, the packaging box 1 may be opened by opening the upper flaps 20 to 23 of each.

A plurality of sealed packaging boxes 1 (containing the contents) are stored or transported in a stacked state. In the state where the packaging boxes 1 are laminated, the pair of second upper flaps 22 and 23 of the packaging box 1 located below are bound by the pair of first lower flaps 30 and 31 of the packaging box 1 located above. It is designed to fit into the configured recess (not shown). As a result, the packaging boxes 1 stacked upward are suppressed from moving in the horizontal direction, and the laminated state of the plurality of packaging boxes 1 can be appropriately maintained.

Further, in the state where the packaging boxes 1 are stacked, the packaging box 1 located below is subjected to a compressive load due to the weight of the packaging box 1 located above. Therefore, the side walls 10, 11 and the end walls 12, 13 of the lower packaging box 1 may bulge outward or buckle. In the above-mentioned packaging box 1, since the end walls 12 and 13 are formed to be narrower (in the flow direction) than the side walls 10 and 11, the end walls 12 and 13 have higher compressive strength than the side walls 10 and 11. ing. Therefore, the side walls 10 and 11 are easy to buckle, and the end walls 12 and 13 are hard to buckle. Further, the side walls 10 and 11 have a structure in which buckling is easy because the compressive strength decreases around the knob line 41 and the side zipper 42. Further, since each of the adjacent walls 10 to 17 is folded along the vertical folding curve L1 to form a solid, the compressive strength is high at the eight corner portions 1C of the packaging box 1. Therefore, in this packaging box 1, the end walls 12 and 13 having relatively high compressive strength and the eight corner portions 1C of the packaging box 1 are configured to bear the compressive load.

As described above, the first upper fold curve L2 and the first lower fold curve L4 are recessed so as to approach each other and are formed in a substantially V shape, and the second lower fold curve L5 is a substantially V shape that is convex downward. It is formed (see FIGS. 2 and 3). Therefore, the upper side of the side walls 10 and 11 forms a substantially V-shaped ridge line recessed downward according to the first upper fold curve L2, and the lower side of the side walls 10 and 11 is upward following the first lower fold curve L4. A substantially V-shaped ridge line recessed in the shape is formed (see FIG. 1). Therefore, the side walls 10 and 11 are long (high) in the vertical direction on both sides in the left-right direction and short (low) in the vertical direction in the middle portion in the left-right direction. On the other hand, the upper sides of the end walls 12 and 13 form a substantially horizontal ridgeline following the second upper fold curve L3, and the lower sides of the end walls 12 and 13 are convex downward following the second lower fold curve L5. A substantially V-shaped ridgeline is formed (see FIG. 1). Therefore, the end walls 12 and 13 are short (low) in the vertical direction on both sides in the front-rear direction and long (high) in the vertical direction in the middle portion in the front-rear direction.

A case where two such packaging boxes 1 are stacked will be described with reference to FIG. FIG. 4 is a perspective view illustrating the distribution of the compressive load when the packaging boxes 1 are stacked. For convenience of explanation, "(U)" is added to the code related to the upper packaging box 1, and "(D)" is added to the code related to the lower packaging box 1. Further, in order to simplify the explanation, the side wall 11 and the end wall 12 among the pair of side walls 10 and 11 and the pair of end walls 12 and 13 will be described. For the same reason as this, the explanation will be focused on one corner portion 1C.

The operator arranges the packaging box 1 (U) above the packaging box 1 (D) in the same direction, and places the packaging box 1 (U) on the top surface of the packaging box 1 (D). Since the lower ridgeline of the end wall 12 (U) of the packaging box 1 (U) protrudes downward, first, the lower end of the end wall 12 (U) is the end wall 12 (D) of the packaging box 1 (D). The compression load begins to act on the end wall 12 (D) (see the longest solid arrow in FIG. 4). Subsequently, the lower end of the corner portion 1C (U) of the packaging box 1 (U) abuts on the upper end of the corner portion 1C (D) of the packaging box 1 (D), and a compressive load acts on the corner portion 1C (D). Get started (see short solid arrow in Figure 4). Then, since the lower ridge line of the side wall 11 (U) of the packaging box 1 (U) is recessed upward and the upper ridge line of the side wall 11 (D) of the packaging box 1 (D) is recessed downward, finally, The lower end of the side wall 11 (U) abuts on the upper end of the side wall 11 (D). In this state, most of the compressive load is dispersed and acts on the pair of end walls 12, 13 and the eight corner portions 1C, so that the pair of side walls 10, 11 receives the remaining slight compressive load. It will be a burden (see the dashed arrow in FIG. 4).

In the packaging box 1 according to the first embodiment described above, the intermediate portion of the upper ridges of the side walls 10 and 11 is recessed downward, and the intermediate portion of the lower ridges of the side walls 10 and 11 is recessed upward. In addition, the middle portion of the lower ridges of the end walls 12 and 13 in the left-right direction protrudes downward. According to this configuration, the end walls 12 and 13 can be formed slightly longer in the vertical direction than the side walls 10 and 11. Therefore, when a plurality of packaging boxes 1 are stacked, most of the compressive load can be received by the end walls 12, 13 of the lower packaging box 1 and the upper ends of the eight corner portions 1C. That is, the compressive load can be borne by the end walls 12, 13 and the corner portion 1C having high load-bearing performance (compressive strength). As a result, it is possible to balance the compressive load acting on the walls 10 to 13 having different compressive strengths, and it is possible to suppress the deformation of the packaging box 1 due to the compressive load.

Further, in the packaging box 1 according to the first embodiment, the second upper flaps 22 and 23 are arranged on the uppermost side. According to this configuration, when a plurality of packaging boxes 1 are stacked, the end walls 12 and 13 of the upper packaging box 1 come into contact with the second upper flaps 22 and 23 of the lower packaging box 1, so that compression from above is performed. The load can be applied to the end walls 12, 13 and the like of the lower packaging box 1. As a result, it is possible to suppress swelling (bending) and buckling of the side walls 10 and 11 having a compressive strength lower than that of the end walls 12 and 13.

In the packaging box 1 according to the first embodiment, the first upper fold curve L2, the first lower fold curve L4, and the second lower fold curve L5 are bent in a substantially V shape. Not limited. As shown in FIG. 5, at least one of these folding curves L2, L4, and L5 (all in FIG. 5) may be formed in a state of being curved in an arc shape. In addition, as shown in FIG. 6, at least one of these folding curves L2, L4, and L5 (all in FIG. 6) is a straight line between a pair of inclined end portions La that are linearly inclined. It may be formed in a substantially trapezoidal shape including the intermediate portion Lb connected in a shape. Further, as shown in FIG. 7, the pair of inclined end portions La may be inclined in an arc shape that is convex toward the side walls 10 and 11. Further, the pair of inclined end portions La may be inclined in an arc shape that is convex on the side opposite to the side walls 10 and 11 (not shown). Further, the folding curves L2, L4, and L5 formed in a V shape, an arc shape, or a trapezoidal shape may be freely combined and applied to the packaging box 1.

Further, in the packaging box 1 according to the first embodiment, both the first upper folding curve L2 and the first lower folding curve L4 are formed so as to be convex toward the side walls 10 and 11, and the second lower folding curve L5. Was formed so as to be convex on the side of the second lower flaps 32 and 33, but the present invention is not limited to this. For example, only one of the first upper turn curve L2 and the first lower turn curve L4 may be formed so as to be convex toward the side walls 10 and 11 (not shown). Further, for example, both the second upper fold curve L3 and the second lower fold curve L5 or the second upper fold curve L3 may be formed so as to be convex toward the second lower flaps 32 and 33 (Fig.). Not shown). In this way, at least one of the first upper fold curve L2 and the first lower fold curve L4 is formed so as to be recessed toward the center of the side walls 10 and 11, and the second upper fold curve L3 and the second lower fold are formed. At least one of the curves L5 may be formed so as to protrude in a direction away from the center of the end walls 12 and 13.

[Second Embodiment]
Next, the packaging box 2 according to the second embodiment will be described with reference to FIGS. 8 and 9.
FIG. 8 is a plan view showing the blank 6 of the packaging box 2. FIG. 9 is a perspective view illustrating the distribution of the compressive load when the packaging boxes 2 are stacked. In the following description, the same or corresponding configurations as those of the packaging box 1 according to the first embodiment are designated by the same reference numerals, and the same or corresponding description as that of the packaging box 1 will be omitted.

As shown in FIG. 9, the packaging box 2 is formed into a substantially octagonal columnar shape by closing both the upper and lower sides of the peripheral wall 2W having a substantially octagonal cross section. As shown in FIG. 8, in the blank 6 of the packaging box 2, the handle hole portion 50 (cutting line) is cut above the center of the end walls 12 and 13 in the vertical direction. The handle hole portion 50 is formed so that an operator can put his / her hand in the packaging box 2 when transporting the packaging box 2. The end walls 12 and 13 are formed to be narrower than the side walls 10 and 11, but the handle hole portion 50 reduces the compressive strength of the end walls 12 and 13. Therefore, in the packaging box 2, buckling of the end walls 12 and 13 is likely to occur around the handle hole portion 50. The pair of top zipper 43 extends to the front of the tip of the first upper flap 21, and a crossing zipper 44 is formed between the tips of the pair of top zippers 43.

<1st upper turn curve, 1st lower turn curve>
Further, a pair of first upper folding curves L20 formed at the boundary between the side walls 10 and 11 and the first upper flaps 20 and 21 are formed substantially parallel to the second upper folding curve L3. Further, the pair of first lower folding curves L40 formed at the boundary between the side walls 10 and 11 and the first lower flaps 30 and 31 are formed so as to be recessed toward the center of the side walls 10 and 11. Specifically, the first lower folding curve L40 has a substantially trapezoidal shape including an intermediate portion Lb linearly connecting between a pair of inclined end portions La inclined in a straight line (or may be an arc shape). It is formed. On the outside of the pair of inclined end portions La, a pair of parallel end portions Lc formed on the virtual line V2 (see FIG. 3) are formed.

<Second upper turn curve, second lower turn curve>
Further, the pair of second lower folding curves L50 formed at the boundary between the end walls 12 and 13 and the second lower flaps 32 and 33 are formed so as to be recessed toward the center of the side walls 10 and 11. Specifically, the second lower fold curve L50 is formed in a substantially trapezoidal shape including a pair of parallel end portions Lc, a pair of inclined end portions La, and an intermediate portion Lb, similarly to the first lower fold curve L40. ..

In the first lower fold curve L40 and the second lower fold curve L50, the maximum value of the distance (step) between the intermediate portion Lb and the parallel end portion Lc is set to about 1 to 2 mm. The first upper fold curve L20, the first lower fold curve L40, and the second lower fold curve L50 are general-purpose ruled lines, but the present invention is not limited to these, and lead ruled lines or the like may be adopted.

In a state where the packaging box 2 is assembled in a substantially octagonal columnar shape, the upper sides of the side walls 10 and 11 form a substantially horizontal ridge line following the first upper folding curve L20, and the lower sides of the side walls 10 and 11 are the first lower folding curve. Following L40, a substantially trapezoidal ridge line recessed upward is formed. Therefore, the side walls 10 and 11 are high on both sides in the left-right direction and low in the middle portion in the left-right direction. On the other hand, the upper sides of the end walls 12 and 13 form a substantially horizontal ridgeline following the second upper fold curve L3, and the lower sides of the end walls 12 and 13 are substantially recessed upward following the second lower fold curve L50. Form a trapezoidal ridge. Therefore, the end walls 12 and 13 are high on both sides in the front-rear direction and low in the middle portion in the front-rear direction.

Here, as shown in FIG. 9, "(U)" is added to the code related to the upper packaging box 1, and "(D)" is added to the code related to the lower packaging box 1, and the side wall 11 A case where a plurality of packaging boxes 2 are stacked will be described with a focus on the end wall 12 and the like.

As described above, since the lower end of the corner portion 2C (U) of the upper packaging box 2 (U) protrudes downward from the lower ridge line of the side wall 11 (U) and the end wall 12 (U), it is upward. The lower end of the corner portion 2C (U) abuts on the upper end of the corner portion 2C (D) of the lower packaging box 2 (D), and a compressive load begins to act on the corner portion 2C (D) (solid line in FIG. 9). See arrow). After that, the lower ends of the side wall 11 (U) and the end wall 12 (U) of the packaging box 2 (U) come into contact with the upper ends of the side wall 11 (D) and the end wall 12 (D) of the packaging box 2 (D). In this state, most of the compressive load is dispersed and acts on the eight corner portions 2C (D), so that the side walls 10 and 11 and the end walls 12 and 13 bear the remaining slight compressive load. (See the dashed arrow in FIG. 9).

In the packaging box 2 according to the second embodiment described above, in the state where the packaging box 2 is assembled, the intermediate portion of the lower ridge lines of the side walls 10 and 11 is recessed upward, and the lower ridge lines of the end walls 12 and 13 are formed. The middle part will be dented upward. According to this configuration, when a plurality of packaging boxes 2 are stacked, the weight (compressive load) of the upper packaging box 2 can be borne by the corner portion 2C having a high load-bearing performance (compressive strength). As a result, swelling and buckling of the side walls 10 and 11 can be suppressed, and buckling of the end walls 12 and 13 whose compressive strength has decreased around the handle hole 50 can be suppressed.

In the packaging box 2 according to the second embodiment, the first lower folding curve L40 and the second lower folding curve L50 are bent into a substantially trapezoidal shape, but the present invention is not limited to this. At least one of these folding curves L40 and L50 may be formed in a substantially V shape like the first lower folding curve L4 of the first embodiment (see FIGS. 2 and 3), or has an arc shape. It may be formed in a curved state (see FIG. 5). Further, the folding curves L40 and L5 formed in a V shape, an arc shape or a trapezoidal shape may be freely combined and applied to the packaging box 2.

Further, in the packaging box 2 according to the second embodiment, the lower first lower fold curve L40 and the second lower fold curve L50 are formed so as to be recessed upward, but the present invention is not limited thereto. For example, the first upper fold curve L20 and the second upper fold curve L3 may be formed so as to be recessed downward (not shown). In this way, at least one of the first upper fold curve L20 and the first lower fold curve L40 is formed so as to be recessed toward the center of the side walls 10 and 11, and the second upper fold curve L3 and the second lower fold are formed. At least one of the curves L50 may be formed so as to be recessed toward the center of the end walls 12 and 13.

Further, in the packaging box 2 according to the second embodiment, the handle hole portion 50 is formed on the end walls 12 and 13 as an example of the cutting line, but the present invention is not limited to this, and the worker hands on the end walls 12 and 13. An opening may be formed to accommodate the (not shown). Further, cutting lines or the like for opening may be formed on the end walls 12 and 13 (not shown).

[Third Embodiment]
The packaging boxes 1 and 2 according to the first and second embodiments (including modified examples) are formed in a substantially octagonal columnar shape, but the present invention is not limited thereto. As shown in FIG. 10, as the packaging box 3 (blank 7) according to the third embodiment, the first upper folding curve L2 and the first lower are obtained with respect to the so-called A-type box in which the four square walls 14 to 17 are omitted. A curved folding curve, which is a feature of the present invention, such as a folding curve L4 and a second lower folding curve L5 may be applied. The packaging box 3 is formed in a substantially rectangular parallelepiped shape by closing both the upper and lower sides of a peripheral wall having a substantially quadrangular cross section (not shown).

In the trays 1 to 3 according to the first to third embodiments, the end walls 12 and 13 are formed to be narrower than the side walls 10 and 11, but the present invention is not limited to this. The end walls 12 and 13 may be formed to have the same width as the side walls 10 and 11, or may be formed wider than the side walls 10 and 11. However, the feature of the present invention exerts the maximum effect when the compressive strength of the side walls 10 and 11 is lower than that of the end walls 12 and 13.

Further, the trays 1 to 3 according to the first to third embodiments are formed of a corrugated cardboard sheet made of paper, but the present invention is not limited to this, and the trays 1 to 3 may be made of thick paper, a resin plate (sheet), or the like. good.

It should be noted that the description of the above embodiment shows one aspect of the packaging box according to the present invention, and the technical scope of the present invention is not limited to the above embodiment.

1,2,3 Packaging box 10,11 Side wall 12,13 End wall 14,15,16,17 Square wall 20,21 First upper flap 22,23 Second upper flap 30,31 First lower flap 32,33 2 Lower flap 50 Handle hole (cutting line)
L2, L20 1st upper turn curve L3 2nd upper turn curve L4, L40 1st lower turn curve L5, L50 2nd lower turn curve

Claims (5)

It ’s a packaging box,
A pair of side walls (10, 11) facing each other in the first direction,
A pair of end walls (12, 13) facing the second direction intersecting the first direction and having a higher compressive strength than the side wall.
The first upper flap (20, 21) connected to the upper end of the side wall via the first upper folding curve (L2), and
The second upper flaps (22, 23) connected to the upper end of the end wall via the second upper folding curve (L3), and
The first lower flap (30, 31), which is continuously provided at the lower end of the side wall via the first lower folding curve (L4),
A second lower flap (32, 33), which is continuously provided at the lower end of the end wall via a second lower folding curve (L5), is provided.
The first upper fold curve and the first lower fold curve are formed so as to be recessed toward the center of the side wall.
The second upper fold curve and the second lower fold curve are formed so as to protrude in a direction away from the center of the end wall.
The bottom surface of the packaging box is formed by bending the first lower flap inward along the first lower folding curve and bending the second lower flap inward along the second lower folding curve.
The top surface of the packaging box is formed by bending the first upper flap inward along the first upper folding curve and bending the second upper flap inward along the second upper folding curve.
The upper side and the lower side of the side wall form a concave ridge line at the center of the side wall following the first upper fold curve and the first lower fold curve.
The upper side and the lower side of the end wall form a ridge line that is convex in a direction away from the center of the end wall, following the second upper fold curve and the second lower fold curve.
When stacking the upper packaging box on the top surface of the lower packaging box, first, the lower end of the end wall of the upper packaging box abuts on the upper end of the end wall of the lower packaging box, and then The lower end of the upper corner portion of the packaging box abuts on the upper end of the lower corner portion of the packaging box, and finally, the lower end of the side wall of the upper packaging box is the lower end of the side wall of the lower packaging box. A packaging box characterized by abutting on the top edge. The packaging box according to claim 1, wherein the end wall is formed to be narrower than the side wall. The first upper fold curve, the first lower fold curve, the second upper fold curve, and the second lower fold curve are formed in a V-shaped bent state or an arc-shaped curved state. The packaging box according to claim 1 or 2. The first upper fold curve, the first lower fold curve, the second upper fold curve and the second lower fold curve are between a pair of inclined ends (La) inclined in an arc shape or a straight line. The packaging box according to any one of claims 1 to 3, wherein the packaging box includes an intermediate portion (Lb) connected in a straight line. Further provided with four square walls (14, 15, 16, 17) provided between the side wall and the end wall.
The pair of side walls, the pair of end walls and the four square walls form an octagonal columnar peripheral wall (1W, 2W).
The packaging box according to any one of claims 1 to 4, wherein the second upper flap is arranged so as to overlap the surface of the first upper flap folded inside the peripheral wall.

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