Packaging box

Abstract

To provide a packaging box capable of effectively suppressing body swelling of a wall body since the wall body is easily deformed regularly at a plurality of ruled lines when a load is applied from above.SOLUTION: In a packaging box side 1A, an end L10 11 (L10 body) is formed with a horizontal ruled line side L20, two upper inclined ruled line side walls and L20 extending in a vertical direction above the horizontal ruled line side L10, and two lower inclined ruled line side walls and L30 extending in the vertical direction below the horizontal ruled line side wall. L30. The distance between the upper ruled lines L20 and L20 decreases from the top to the bottom. The distance between the two lower ruled lines L30, L30 increases from top to bottom. The top portion 20 has a top plate 21 connected to the upper edge portion side L1 of the end L1 11, and the upper edge portion side wall of the end wall 11 is bent so as to protrude toward the tip end side of the top plate 21.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] When cardboard packaging boxes are stacked, a load from above can cause the walls to bend outward and bulge, deteriorating the appearance of the packaging boxes. Conventional packaging boxes that can cope with bulging include those that have a crease formed in the center of the wall extending vertically (see, for example, Patent Document 1). With this configuration, when a load is applied from above, the wall bends at one crease, thereby suppressing bulging. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-042558 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to effectively prevent the packaging box from bulging, it is preferable that the wall body be deformed regularly when a load is applied from above. An object of the present invention is to provide a packaging box that can effectively prevent the wall body from bulging when a load is applied from above. [Means for solving the problem]

[0005] To solve the above-mentioned problems, the present invention provides a packaging box comprising a cylindrical body having a plurality of walls, a top provided at an upper opening of the body, and a bottom provided at a lower opening of the body. The walls are formed with a horizontal line extending horizontally, two upper oblique lines extending vertically above the horizontal line, and two lower oblique lines extending vertically below the horizontal line. The upper oblique lines are spaced apart horizontally, with the distance between the upper oblique lines decreasing from top to bottom. The lower oblique lines are spaced apart horizontally, with the distance between the lower oblique lines increasing from top to bottom. The top has a top plate connected to the upper edge of the wall via the upper line, and the upper edge of the wall is bent to protrude toward the tip of the top plate.

[0006] In the packaging box of the present invention, when the top plate is bent along the upper crease toward the wall, the upper end of the wall is deformed so as to enter the inside of the body. When the upper end of the wall enters the inside of the body, a force pushing the entire wall outward acts on the wall. By applying an outward pushing force to the wall body in this way, the wall body becomes more likely to deform along the multiple lines when a load is applied to the packaging box from above. When the wall body deforms along each line, multiple inclined surfaces are formed on the wall body, with each line as a boundary. This effectively prevents the wall body from bulging and improves the appearance even when the wall body is deformed. Furthermore, in the packaging box of the present invention, the upper end of the wall body is deformed so as to enter the inside of the body portion, thereby improving the load resistance against a load from above.

[0007] In the above-mentioned packaging box, if the upper ends of the two upper inclined lines are connected to both ends of the upper edge of the wall, the load acting on the packaging box from above will be more easily transmitted to the two upper inclined lines, so that the load from above can be reliably applied to each line of the wall.

[0008] In the packaging box described above, if the entire upper edge of the wall is curved in an arc, the upper end of the wall can be deformed neatly when the top plate is bent relative to the wall. In addition, if the curvature of the upper edge of the wall is increased, when the top plate is bent relative to the wall, the upper end of the wall will be significantly recessed inside the body, causing the upper part of the wall to be significantly tilted toward the inside of the body. This results in a clearly defined inclined surface at the top of the wall, surrounded by the top line, both upper inclined lines, and the horizontal line, allowing the packaging box to be formed into a distinctive shape.

[0009] In the packaging box described above, the top plates may be connected to the upper edge portions of the left and right walls, respectively, and handle plates may be connected to the tip edge portions of both the top plates, and the handle plates may be raised from the top plates so that both the handle plates are overlapped. In this configuration, when the top plate is bent relative to the wall body, the upper end of the wall body (the base end of the top plate) fits inside the body, pressing the leading edges of both top plates together. This increases the strength of the top when the handle plates are placed on and pulled up.

[0010] In the packaging box described above, it is preferable that the bottom portion has front and rear insertion flaps connected to the lower edges of the wall body, and left and right bottom flaps connected to the lower edges of the left and right wall body, respectively. In this case, recesses are formed in the leading edge portions of both bottom flaps, and a connecting opening is formed by the two recesses. The leading ends of both insertion flaps are inserted into the connecting opening from the outside. The insertion flaps have cutouts formed in the left and right edges, and the cutouts engage with the edges of the recesses.

[0011] When assembling the bottom, the insertion flaps are pushed into the body from the outside by the insertion flaps. Then, the connecting opening is opened to the left and right, and the leading ends of the insertion flaps are inserted into the connecting opening. After that, when the bottom flaps are returned to their flat state, the notches of the insertion flaps engage with the edges of the recesses of the bottom flaps.

[0012] In the above-described configuration, the entire connecting opening is not blocked before the insertion flap is inserted into the connecting opening, making it easy to insert the tip of the insertion flap into the connecting opening when assembling the bottom part. The notch of the insertion flap engages with the edge of the recess of the bottom flap, ensuring a secure connection between the insertion flap and the bottom flap. Furthermore, the notch of the insertion flap engages with the edge of the recess of the bottom flap, making it difficult for the tip of the insertion flap to slip out of the connecting opening, thereby increasing the strength of the bottom part.

[0013] In the packaging box described above, the length of the insertion flap in the front-to-rear direction is formed to be greater than half the length of the opening at the bottom of the body in the front-to-rear direction, so that when the bottom is assembled, the leading edges of the insertion flaps abut against each other, causing the insertion flaps to tilt so as to enter the body, and the insertion flaps are pushed by the insertion flaps so as to tilt so as to enter the body.

[0014] In the above-described configuration, the underside of the bottom of the packaging box is recessed. Also, in the packaging box of the present invention, the upper end of the wall body is deformed so as to fit inside the body. Therefore, when multiple packaging boxes are stacked, the upper end of the lower packaging box fits into the recess in the bottom of the upper packaging box, allowing multiple packaging boxes to be stacked stably. [Effects of the Invention]

[0015] In the packaging box of the present invention, when a load is applied from above, the wall body is likely to deform regularly along the multiple lines, so that the wall body is effectively prevented from swelling and the appearance can be improved even when the wall body is deformed. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a perspective view of a packaging box according to a first embodiment of the present invention, viewed from the upper right front side. FIG. [Figure 2] 1 is a perspective view of a packaging box according to a first embodiment of the present invention, viewed from the upper right rear side. FIG. [Figure 3] 1 is a diagram showing a blank sheet for a packaging box according to a first embodiment of the present invention. FIG. [Figure 4] FIG. 10 is a perspective view of a handheld form of a packaging box according to a second embodiment of the present invention, as viewed from the front upper right. [Figure 5] FIG. 10 is a diagram showing a blank sheet for a packaging box according to a second embodiment of the present invention. [Figure 6] FIG. 10 is a perspective view of a storage form of a packaging box according to a second embodiment of the present invention, as viewed from the front upper right. [Figure 7] FIG. 10 is a bottom view showing a packaging box according to a second embodiment of the present invention. [Figure 8] FIG. 10 is a bottom view showing a packaging box according to a second embodiment of the present invention before the insertion flap is closed. [Figure 9] FIG. 10 is a perspective view of a handheld form of a packaging box according to a third embodiment of the present invention, as viewed from the front upper right. [Figure 10] FIG. 10 is a diagram showing a blank sheet for a packaging box according to a third embodiment of the present invention. [Figure 11] FIG. 10 is a perspective view of a packaging box according to a fourth embodiment of the present invention, viewed from the lower front right. [Figure 12] FIG. 10 is a diagram showing a blank sheet for a packaging box according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the front, rear, left and right directions are set for the convenience of describing the packaging box of each embodiment, and do not limit the configuration or usage state of the packaging box. In the description of each embodiment, the same components are denoted by the same reference numerals, and duplicated descriptions will be omitted.

[0018] [First embodiment] As shown in Figures 1 and 2, the packaging box 1A of the first embodiment is an A-type cardboard box, and has a body 10 formed in a rectangular cylindrical shape, a top 20 provided at the upper opening of the body 10, and a bottom 30 provided at the lower opening of the body 10.

[0019] The packaging box 1A of the first embodiment is formed by mountain-folding or valley-folding a blank sheet S1 cut out from a cardboard sheet at each fold line, as shown in Fig. 3. The blank sheet S1 shown in Fig. 3 is arranged so that the inner side is visible. The fold lines of the blank sheet S1 are creases (pressed creases) formed by linearly pressing the surface of the blank sheet S1. Note that the creases may also be formed with intermittent slits. This makes it easier to fold the blank sheet S1 at the crease lines. Alternatively, the folded line may be formed by forming a half-cut slit only on the surface of the sheet or by forming an intermittent slit that penetrates the sheet.

[0020] 1 and 2, the body 10 has a pair of front and rear end walls 11, 11 and a pair of left and right side walls 12, 12. The end wall 11 and the side wall 12 are rectangular wall bodies. In the first embodiment, a strip-shaped joining piece 13 is provided continuously at the left edge of the rear end wall 11. The joining piece 13 is attached to the inner surface of the left side wall 12.

[0021] When the blank sheet S1 (see Figure 3) is folded along each fold line and the joining piece 13 is joined to the inner surface of the left side wall 12, the front and rear end walls 11, 11 and the left and right side walls 12, 12 form a cylindrical body 10 that is rectangular in plan view.

[0022] The top portion 20 comprises a pair of front and rear top plates 21, 21 connected to the upper edge portions L1, L1 of the front and rear end walls 11, 11, respectively, and a pair of left and right inner flaps 22, 22 connected to the upper edge portions of the left and right side walls 12, 12, respectively. The top portion 20 is formed by stacking the top plates 21, 21 on the upper surfaces of the inner flaps 22, 22. The leading edges of the top plates 21, 21 butt against each other, and the top portion 20 closes the opening on the upper side of the body portion 10.

[0023] The bottom 30 has a pair of front and rear outer flaps 31, 31 connected to the lower edge portions L2, L2 of the front and rear end walls 11, 11, respectively, and a pair of left and right inner flaps 32, 32 connected to the lower edge portions of the left and right side walls 12, 12, respectively. The bottom 30 is formed by overlapping the two outer flaps 31, 31 on the undersides of the two inner flaps 32, 32. The leading edges of the two outer flaps 31, 31 are butted together, and the bottom 30 closes the opening on the lower side of the body 10.

[0024] In the packaging box 1A of the first embodiment, the entire upper edge portion L1 of the end wall 11 is bent in an arc shape so as to protrude toward the tip end side of the top plate 21 (see FIG. 3). An upper crease L3 is formed on the upper edge L1 of the end wall 11. That is, the top plate 21 is connected to the upper edge of the end wall 11 via the upper crease L3, which is bent in an arc shape.

[0025] As shown in FIG. 1, the front end wall 11 is formed with a horizontal line L10 extending horizontally, two upper inclined lines L20, L20 arranged on the left and right above the horizontal line L10, and two lower inclined lines L30, L30 arranged on the left and right below the horizontal line L10. The horizontal crease L10, the upper inclined crease L20, and the lower inclined crease L30 are creases (pressed creases) formed by pressing the inner surface of the end wall 11 linearly.

[0026] The horizontal crease L10 is formed on the upper portion of the end wall 11 and is located in the center of the end wall 11 in the left-right direction. The horizontal crease L10 extends linearly in the left-right direction parallel to the lower edge L2 of the end wall 11 (see FIG. 3). The length of the horizontal crease L10 is shorter than the length of the lower edge L2 of the end wall 11. The ends of the horizontal crease L10 are spaced apart from the left and right edges of the end wall 11.

[0027] The upper inclined crease L20 extends linearly in the vertical direction and is inclined downwards toward the center of the end wall 11 in the horizontal direction (see FIG. 3). The upper inclined creases L20, L20 are arranged in the region of the end wall 11 above the horizontal crease L10, spaced apart in the left-right direction. The distance between the upper inclined ruled lines L20, L20 in the left-right direction becomes smaller from top to bottom (see FIG. 3).

[0028] The upper end of the left upper slanted crease L20 is connected to the left end of the upper edge L1 (upper crease L3) of the end wall 11. The upper end of the right upper slanted crease L20 is connected to the right end of the upper edge L1 (upper crease L3) of the end wall 11. In this way, the upper end of the upper slanted crease L20 is connected to the upper corner of the end wall 11. The lower end of the left upper slanted ruled line L20 is connected to the left end of the horizontal ruled line L10, and the lower end of the right upper slanted ruled line L20 is connected to the right end of the horizontal ruled line L10.

[0029] The lower inclined crease L30 extends linearly in the vertical direction and is inclined downward toward the side opposite the center of the end wall 11 in the horizontal direction (toward the side edge of the end wall 11) (see FIG. 3). The lower inclined creases L30, L30 are arranged in the region of the end wall 11 below the horizontal crease L10, spaced apart in the left-right direction. The distance between the lower inclined ruled lines L30, L30 in the left-right direction increases from top to bottom (see FIG. 3).

[0030] The upper end of the left lower slanted ruled line L30 is connected to the left end of the horizontal ruled line L10 and the lower end of the left upper slanted ruled line L20, and the upper end of the right lower slanted ruled line L30 is connected to the right end of the horizontal ruled line L10 and the lower end of the right upper slanted ruled line L20. The lower end of the left lower oblique crease L30 extends toward the left end of the lower edge L2 of the end wall 11. The lower end of the right lower oblique crease L30 extends toward the right end of the lower edge L2 of the end wall 11. In this way, the lower end of the lower oblique crease L30 extends toward the lower corner of the end wall 11. In the first embodiment, the lower end of the lower inclined line L30 is separated from the end of the lower edge portion L2 of the end wall 11, but the lower end of the lower inclined line L30 may also be connected to the end of the lower edge portion L2 of the end wall 11.

[0031] As shown in Figure 2, the upper edge L1 of the rear end wall 11, like the upper edge L1 of the front end wall 11 (see Figure 1), is curved in an arc shape so as to protrude toward the tip of the top plate 21. Also, like the front end wall 11 (see Figure 1), the rear end wall 11 is formed with an upper line L3, a horizontal line L10, left and right upper oblique line L20, L20, and left and right lower oblique line L30, L30.

[0032] 1 and 2, when the top plate 21 of the packaging box 1A described above is bent relative to the end wall 11, the upper end of the end wall 11 is deformed along the arc-shaped upper edge L1 (upper ruled line L3), and the upper end of the end wall 11 enters the inside of the body 10. As a result, when the packaging box 1A is assembled, a force pushing the entire end wall 11 outward acts on it. In this way, if a force pushing outward is applied to the end wall 11, when a load acts on the packaging box 1A from above, the end wall 11 becomes more likely to deform along the multiple creases L10, L20, and L30. When the end wall 11 is deformed at each of the creases L10, L20, and L30, a plurality of inclined surfaces are formed on the end wall 11 with the creases L10, L20, and L30 as boundaries.

[0033] In addition, in the packaging box 1A of the first embodiment, the upper ends of both upper inclined lines L20, L20 are connected to the upper corners of the end wall 11, respectively, so that the load acting on the packaging box 1A from above is easily transmitted to both upper inclined lines L20, L20.

[0034] Therefore, in the packaging box 1A of the first embodiment, when a load is applied from above, the end wall 11 is likely to deform regularly at the multiple lines L10, L20, and L30, which effectively suppresses the bulging of the end wall 11 and improves the appearance even when the end wall 11 is deformed.

[0035] In the packaging box 1A of the first embodiment, the upper ends of the front and rear end walls 11, 11 are deformed so as to enter the inside of the body 10, and therefore the load resistance against a load from above can be improved.

[0036] In the packaging box 1A of the first embodiment, the entire upper edge L1 of the end wall 11 is curved in an arc shape, so that when the top plate 21 is bent relative to the end wall 11, the upper end of the end wall 11 can be deformed neatly.

[0037] Although the first embodiment of the present invention has been described above, the present invention is not limited to the first embodiment and can be modified as appropriate within the scope of the invention. In the packaging box 1A of the first embodiment, the top line L3, the upper oblique lines L20, L20, the horizontal line L10, and the lower oblique lines L30, L30 are continuous as shown in Fig. 1. However, all or some of the top line L3, the upper oblique lines L20, L20, the horizontal line L10, and the lower oblique lines L30, L30 may be spaced apart.

[0038] In the packaging box 1A of the first embodiment, the upper crease L3 is curved in an arc shape, but the shape of the upper crease is not limited to this. For example, a straight upper crease may be bent or inclined so as to protrude toward the tip of the top plate 21.

[0039] In the packaging box 1A of the first embodiment, the upper edges of both the end wall 11 and the side wall 12 may be bent so as to protrude toward the top 20, and an upper line L3, an upper inclined line L20, a horizontal line L10, and a lower inclined line L30 may be formed on both the end wall 11 and the side wall 12.

[0040] In the first embodiment, there is no limitation on the configuration of the top portion 20 and the bottom portion 30. For example, the top portion may be formed by one top plate, and the bottom portion may be formed by one bottom plate.

[0041] In the packaging box 1A of the first embodiment, the body 10 is formed into a rectangular cylindrical shape by four walls (two end walls 11, 11 and two side walls 12, 12), but the number of walls forming the body 10 is not limited. For example, an inclined wall may be provided between the end wall 11 and the side wall 12, so that the body 10 is formed into a hexagonal or octagonal cylindrical shape.

[0042] The packaging box 1A of the first embodiment is made of corrugated cardboard, but the packaging box may also be made of various known paperboards. The present invention is applicable to various types of packaging boxes, including, for example, wrap-around type packaging boxes.

[0043] [Second embodiment] Next, a packaging box 1B of a second embodiment will be described. The packaging box 1B of the second embodiment shown in Fig. 4 differs from the packaging box 1A of the first embodiment (see Fig. 1) in the configuration of the top part 50 and the bottom part 60. The packaging box 1B of the second embodiment is formed by mountain-folding or valley-folding the blank sheet S2 shown in Fig. 5 at each fold line. The blank sheet S2 shown in Fig. 5 is arranged so that the inner side is visible.

[0044] As shown in Figure 4, the top 50 of the packaging box 1B of the second embodiment has a pair of front and rear top plates 51, 51 connected to the front and rear end walls 11, 11, respectively, a pair of front and rear handle plates 52, 52 connected to the top plates 51, 51, respectively, and a pair of left and right connecting plates 53, 53 connected to the left and right side walls 12, 12, respectively. The top portion 50 of the second embodiment can be assembled into two configurations: a handheld configuration shown in FIG. 4, and a storage configuration shown in FIG.

[0045] 4, the top plate 51 is connected to the upper edge L1 of the end wall 11. When the top portion 50 is assembled into a handheld form, the front top plate 51 closes the front half of the upper opening of the body portion 10, and the rear top plate 51 closes the rear half of the upper opening of the body portion 10.

[0046] A front handle plate 52 is connected to the leading edge of the front top plate 51, and a rear handle plate 52 is connected to the leading edge of the rear top plate 51 (see Figure 5). A handle hole 54 is formed in the end of the handle plate 52 on the top plate 21 side.

[0047] 5, the handle hole 54 of the rear handle plate 52 is closed by a connecting piece 55. The lower edge of the connecting piece 55 is connected to the rear top plate 51 via a fold line, and the edges of the connecting piece 55 other than the lower edge are separated from the inner edge of the handle hole 54. The handle hole 54 of the front handle plate 52 is closed by a folded piece 56. The upper edge of the folded piece 56 is connected to the upper edge of the handle hole 54 of the front handle plate 52 via a fold line, and the edges of the folded piece 56 other than the upper edge are separated from the inner edge of the handle hole 54.

[0048] In the handheld top portion 50 shown in Figure 4, the handle plate 52 is raised vertically relative to the top plate 51, and the front and rear handle plates 52, 52 are stacked one on top of the other. At this time, the hand-holding holes 54, 54 of the handle plates 52, 52 are connected to each other. In addition, the connecting piece 55 passes through the hand-holding hole 54 of the front handle plate 52 and is stacked on the top surface of the front top plate 21. Furthermore, the folded-back piece 56 passes through the hand hole 54 of the rear handle plate 52, is folded back upward, and is placed on the outer surface of the rear handle plate 52. This prevents the upper edges of the hand hole 54 from directly touching the palms when the hands are placed in the hand hole 54, making it easier to hold both handle plates 52.

[0049] The connecting plate 53 is connected to the upper edge of the side wall 12. When assembling the top part 50 into a handheld form, the connecting plate 53 is folded in half and raised from the upper edge of the side wall 12. A slit-shaped insertion hole 53a extending in the vertical direction is formed in the center of the connecting plate 53 in the front-to-rear direction. Then, the connecting plate 53 is inclined inward relative to the side wall 12, and the left and right ends of both handle plates 52, 52 are inserted into the insertion holes 53a, whereby both handle plates 52, 52 are fixed in an overlapping state. When carrying the packaging box 1B, the top portion 50 is assembled into a hand-held form, and the box is gripped by passing fingers through the two hand holes 54, 54 of the handle plates 52, 52.

[0050] In the hand-held top portion 50, when the top plate 51 is bent relative to the end wall 11, the upper end of the end wall 11 (the base end of the top plate 51) enters the inside of the body 10, so that the tip edges of both top plates 51, 51 are pressed against each other. This increases the strength of the top portion 50 when the handle plates 52, 52 are placed on the top portion 50 and pulled up.

[0051] In the top portion 50 in the storage configuration shown in Figure 6, the rear top plate 51 and handle plate 52 are placed on top of the front top plate 51 and handle plate 52. Note that both connecting plates 53, 53 (see Figure 5) are disposed within the upper opening of the body portion 10 and are placed on the underside of the top plate 51 and handle plate 52. In addition, in the top portion 50 in the storage state, the connecting piece 55 is inserted into the underside of the front top plate 51, thereby fixing both top plates 51, 51 in a closed state.

[0052] In the top portion 50 of the second embodiment, there are no limitations on the shape or configuration of the handle plate 52. For example, the handle plate 52 may be provided on only one of the front and rear top plates 51, 51.

[0053] As shown in Figure 7, the bottom 60 of the second embodiment has a pair of front and rear insertion flaps 70, 70 connected to the lower edge portions L2, L2 of the front and rear end walls 11, 11, respectively, and a pair of left and right bottom plate flaps 80, 80 connected to the lower edge portions of the left and right side walls 12, 12, respectively. 8, the left bottom flap 80 covers the left side of the opening at the bottom of the body 10. The right bottom flap 80 covers the right side of the opening at the bottom of the body 10.

[0054] A recessed portion 81 is formed at the tip edge of the bottom plate flap 80. The recessed portion 81 is a recess formed by depressing the center of the tip edge of the bottom plate flap 80. The width of the recessed portion 81 in the front-to-rear direction increases from the base end to the tip.

[0055] In the second embodiment, the leading edge portions of both bottom plate flaps 80, 80 are spaced apart in the left-right direction, and both recesses 81, 81 are arranged facing each other. As a result, a connecting opening 82 is formed in the center of the bottom 60.

[0056] Protrusions 83 that protrude inward are formed on the left and right edges (bottom sides) of the recess 81. Front and rear second cutouts 84, 84 are formed between the front and rear edges of the recess 81 and the front and rear edges of the protrusions 83. A convex portion 85 that protrudes inward is formed in the center of the tip edge of the protrusion 83. The outer shape of the convex portion 85 is curved in an arc shape.

[0057] The insertion flap 70 is formed so that its width in the front-rear direction decreases from the base end to the tip end. Left and right first catch portions 71, 71 are formed in the approximate centers of the left and right side edges of the insertion flap 70. The opening width of the first catch portion 71 increases from the inner end toward the outer end. The insertion flap 70 has a shape constricted by the first inclusion portions 71, 71. The insertion flap 70 is divided into a base end portion and a tip end portion with the first inclusion portions 71, 71 as the boundary.

[0058] As shown in FIG. 7, the front insertion flap 70 is placed on the underside of the front portions of both bottom plate flaps 80, 80, and the rear insertion flap 70 is placed on the underside of the rear portions of both bottom plate flaps 80, 80. The tip of the insertion flap 70 is inserted from below into the connecting opening 82. The left and right portions of the tip of the insertion flap 70 are overlapped on the upper surface of the bottom plate flap 80. In this way, the tip of the insertion flap 70 is engaged with the inner surfaces of the left and right bottom plate flaps 80, 80. The leading edge portions of the front and rear insertion flaps 70, 70 are butted against each other, and the connecting opening 82 is closed by both insertion flaps 70, 70.

[0059] When the tip of the insertion flap 70 is inserted into the connecting opening 82, the first insertion portion 71 of the insertion flap 70 and the second cutout portion 84 of the bottom plate flap 80 are engaged with each other. A protruding portion 83 of the bottom plate flap 80 overlaps the underside of the leading ends of both insertion flaps 70. A convex portion 85 overlaps the outer surface of the butted portion where the leading edge portions of both insertion flaps 70 meet.

[0060] Next, a procedure for assembling the bottom part 60 of the second embodiment will be described. First, as shown in FIG. 8, the left and right bottom flaps 80, 80 are folded inward of the body 10 relative to the left and right side walls 12, 12. 7, the front and rear insertion flaps 70 are folded toward the inside of the body 10 relative to the front and rear end walls 11, 11, and the insertion flaps 70 are placed on the undersides of the bottom plate flaps 80. As a result, the tip of the insertion flap 70 is positioned below the connecting opening 82.

[0061] When the leading ends of the insertion flaps 70 are pushed toward the inside of the body 10, the insertion flaps 70 push and tilt the bottom flaps 80 toward the inside of the body 10. This causes the connecting opening 82 between the bottom flaps 80 to expand in the left-right direction. Then, the tip ends of both insertion flaps 70, 70 are inserted into the connecting opening 82 and enter the inner surfaces of both bottom plate flaps 80, 80.

[0062] When the bottom flaps 80 are returned to their flat position, the leading edge of the insertion flap 70 overlaps the upper surfaces of the bottom flaps 80. This causes the leading edges of the insertion flaps 70 to engage with the upper surfaces of the bottom flaps 80. Furthermore, when both bottom plate flaps 80, 80 are returned to their flat state, the first notch portion 71 of the insertion flap 70 and the second notch portion 84 of the bottom plate flap 80 are engaged with each other. Furthermore, when the leading ends of the insertion flaps 70, 70 are locked to the inner surfaces of the bottom plate flaps 80, 80, the protrusions 83 and convex portions 85 of the bottom plate flap 80 are pressed against the lower surfaces of the insertion flaps 70, 70.

[0063] In the bottom portion 60 of the second embodiment as described above, the tip portions of both insertion flaps 70, 70 are inserted into the connecting opening 82 between both bottom plate flaps 80, 80, thereby forming the bottom portion 60 at the opening on the lower side of the body portion 10. Furthermore, when the leading ends of both insertion flaps 70, 70 are inserted into the connecting opening 82, the connecting opening 82 widens, making it easy to insert the leading ends of both insertion flaps 70, 70 into the connecting opening 82. Therefore, in the packaging box 1B of the second embodiment, the bottom 60 can be easily assembled without using adhesive tape or adhesive. Furthermore, in the packaging box 1B of the second embodiment, the protruding portion 83 and the convex portion 85 of the bottom flap 80 are overlapped with the lower surfaces of both insertion flaps 70, 70, so that both insertion flaps 70, 70 can be prevented from opening.

[0064] In the bottom portion 60 of the second embodiment, the leading edges of both insertion flaps 70, 70 abut against each other, but the leading edges of both insertion flaps 70, 70 may be spaced apart. Also, in the bottom portion 60 of the second embodiment, the leading edges of both bottom plate flaps 80, 80 are spaced apart, but the leading edges of both bottom plate flaps 80, 80 may abut against each other.

[0065] In the bottom portion 60 of the second embodiment, as shown in FIG. 8, left and right first insertion portions 71, 71 are formed on the insertion flap 70, but the first insertion portion 71 may be formed on only one of the left and right sides. Alternatively, the first recess 71 of the insertion flap 70 may be configured to engage with the edge of the recess 81 without forming the second recess 84 in the recess 81 of the bottom plate flap 80 .

[0066] There are no limitations on the shapes of the protrusions 83 and the convex portions 85 of the bottom plate flap 80. Furthermore, the bottom plate flap 80 does not necessarily need to have the protrusions 83 and the convex portions 85 formed thereon.

[0067] The second embodiment of the present invention has been described above, but the present invention is not limited to the second embodiment, and similar to the first embodiment, it can be modified as appropriate within the scope of the spirit thereof.

[0068] [Third embodiment] Next, a packaging box 1C of a third embodiment will be described. The packaging box 1C of the third embodiment shown in Fig. 9 differs from the packaging box 1B of the second embodiment (see Fig. 4) in the shape of the upper edge portion L1 (upper ruled line L3) of the end wall 11. The packaging box 1C of the third embodiment is formed by mountain-folding or valley-folding the blank sheet S3 shown in Fig. 10 at each fold line. The blank sheet S3 shown in Fig. 10 is arranged so that the inner side is visible.

[0069] The curvature of the upper ruled line L3 in the third embodiment is greater than the curvature of the upper ruled line L3 in the second embodiment (see FIG. 4). In this configuration, when the top plate 51 is bent relative to the end wall 11, the upper portion of the end wall 11 is significantly tilted toward the inside of the body 10. As a result, an inclined surface is clearly formed at the upper portion of the end wall 11 of the packaging box 1C, surrounded by the upper edge L1 (upper crease L3) of the end wall 11, both upper inclined creases L20, L20, and the horizontal crease L10. As described above, the packaging box 1C of the third embodiment has an upper portion of the end wall 11 with a characteristic shape.

[0070] Furthermore, in the packaging box 1C of the third embodiment, when the top plate 51 is folded relative to the end wall 11, the upper end of the end wall 11 (the base end of the top plate 51) is pushed significantly inside the body 10. This causes the leading edges of the top plates 51 to be pressed firmly against each other, and the leading edges of the top plates 51 are pressed down so as to enter the inside of the body 10, thereby reliably increasing the strength of the top 50 when the handle plates 52 are placed on and pulled up.

[0071] In addition, although the packaging box 1C of the third embodiment has a handle plate 52 provided on the top 50, it is not necessary to provide a handle plate 52 on the top 50 as in the packaging box 1A of the first embodiment (see FIG. 1).

[0072] The third embodiment of the present invention has been described above, but the present invention is not limited to the third embodiment, and similar to the first and second embodiments, modifications can be made as appropriate within the scope of the invention.

[0073] [Fourth embodiment] Next, a packaging box 1D of the fourth embodiment will be described. The packaging box 1D of the fourth embodiment shown in Fig. 11 differs from the packaging box 1B of the second embodiment (see Fig. 7) in the structure of the bottom part 60. The packaging box 1D of the fourth embodiment is formed by mountain-folding or valley-folding the blank sheet S4 shown in Fig. 12 at each fold line. The blank sheet S4 shown in Fig. 12 is arranged so that the inner side is visible.

[0074] In the bottom portion 60 of the fourth embodiment, as shown in Fig. 12, an extension portion 72 protrudes from half of the leading edge of the insertion flap 70. Then, as shown in Fig. 11, half of the leading edge of the front and rear insertion flaps 70, 70 abut against each other, and the extension portion 72 of one insertion flap 70 is overlapped on the inner surface of half of the leading edge of the other insertion flap 70. In this way, by vertically interlocking the leading edges of both insertion flaps 70, 70, the strength of the bottom portion 60 can be increased.

[0075] In the bottom portion 60 of the fourth embodiment, the length in the front-to-rear direction from the tip edge to the base edge of the insertion flap 70 is formed to be greater than half the length in the front-to-rear direction of the opening on the lower side of the body portion 10. In this configuration, when the leading edge portions of the insertion flaps 70, 70 are brought into contact with each other, the insertion flaps 70, 70 tilt so as to enter the interior of the body portion 10. In addition, pressed by the insertion flaps 70, 70, the bottom plate flaps 80, 80 also tilt so as to enter the interior of the body portion 10.

[0076] As described above, in the packaging box 1D of the fourth embodiment, the lower surface of the bottom 60 is recessed. Also, in the present invention, the upper portions of the end walls 11 are deformed so as to fit inside the body 10 (see FIGS. 1, 4, and 9). Therefore, when multiple packaging boxes 1D are stacked, the upper end of the lower packaging box 1D fits into the recess in the bottom 60 of the upper packaging box 1D, allowing multiple packaging boxes 1D to be stacked stably.

[0077] The fourth embodiment of the present invention has been described above, but the present invention is not limited to the fourth embodiment, and similar to the first to third embodiments, modifications can be made as appropriate without departing from the spirit of the present invention. [Explanation of symbols]

[0078] 1A Packaging box (first embodiment) 1B Packaging box (second embodiment) 1C Packaging box (third embodiment) 1D Packaging box (fourth embodiment) 10. Torso 11 End Wall 12 Side wall 13 Joint piece 20 Top portion (first embodiment) 21 Top plate 22 Inner flap 30 bottom (first embodiment) 31 Outer flap 32 Inner flap 50 Top portion (second embodiment, third embodiment) 51 Top plate 52 Handle board 53 Connecting plate 53a Insertion hole 54 Handle hole 55 Connecting piece 56 Folding piece 60 Bottom portion (Second embodiment, third embodiment, fourth embodiment) 70 Insertion flap 71 First Section 72 Extension part 80 Bottom flap 81 Recess 82 Connection port 83 Protrusion 84 Second cut 85 Convex part L1 Upper edge of end wall L2 lower edge L3 top border L10 horizontal ruled line L20 Upper slanted rule L30 Lower Slanted Rule S1 Blank sheet (first embodiment) S2 Blank sheet (second embodiment) S3 Blank sheet (third embodiment) S4 Blank sheet (fourth embodiment)

Claims

1. a cylindrical body having a plurality of walls; a top portion provided at an upper opening of the body portion; a bottom portion provided at an opening on the lower side of the body portion, The wall body has: a horizontal ruled line extending in the horizontal direction; two upper inclined creases extending in the vertical direction above the horizontal creases; two lower inclined creases extending in the up-down direction below the horizontal creases; The upper oblique lines are arranged at a horizontal interval, and the interval between the upper oblique lines becomes smaller from top to bottom, The two lower oblique lines are arranged at a horizontal interval, and the interval between the two lower oblique lines increases from top to bottom, The top portion is a top plate connected to the upper edge of the wall body via an upper crease; The packaging box is characterized in that the upper edge of the wall is bent so as to protrude toward the tip end side of the top plate.

2. The packaging box according to claim 1, The upper ends of the upper inclined lines are connected to both ends of the upper edge of the wall body, respectively.

3. The packaging box according to claim 1, The packaging box is characterized in that the entire upper edge of the wall is curved in an arc shape.

4. The packaging box according to claim 1, The top plate is connected to the upper edge portions of the left and right wall bodies, respectively, A handle plate is connected to each of the tip edges of the top plates, The handle plate is raised from the top plate, A packaging box characterized in that both handle plates are overlapped.

5. The packaging box according to claim 1, The bottom portion is front and rear insertion flaps respectively connected to the lower edge of the wall body; left and right bottom plate flaps respectively connected to the lower edge portions of the left and right wall bodies, A recess is formed at the tip edge of each of the bottom plate flaps, A connecting port is formed by the two recessed portions of the two bottom plate flaps, The tip ends of the insertion flaps are inserted into the connecting opening from the outside, The insertion flap has recessed portions formed from the left and right edges, A packaging box characterized in that the notch portion is engaged with the edge of the recessed portion.

6. The packaging box according to claim 5, The length of the insertion flap in the front-rear direction is greater than half the length of the opening at the bottom of the body in the front-rear direction, The leading edge portions of the insertion flaps abut against each other, The insertion flaps are inclined so as to enter the interior of the body portion, The packaging box is characterized in that both bottom flaps are inclined so as to enter the inside of the body portion.

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