Packaging box

Abstract

To provide a packaging box that makes it easier to assemble a lid plate and also can increase the strength of the lid plate.SOLUTION: In a packaging box 1A, a lower lid plate 30 at an opening of a body 10 has left and right side flaps 40, 40 and front and rear end flaps 50, 50. A connection opening 42 is formed by both recesses 41, 41 formed in both the side flaps 40, 40. A tip 52 of each end flap 50 is inserted into the connection openings 42 from the outside, and the tips 52, 52 of both the end flaps 50, 50 at least partially overlap each other. First notches 61 are formed in left and right edges of each end flap 50. The first notches 61 are engaged with edges of the recesses 41.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] As for the lid plate (bottom plate) of a cardboard packaging box, there is one in which front and rear end flaps are overlapped on the undersides of the left and right side flaps, and the tips of both end flaps are inserted into the front and rear connecting openings formed where the side flaps are butted together (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3912537 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned conventional packaging box, since the entire connecting opening is blocked, there is a problem that it is difficult to insert the tip of the end flap into the connecting opening when assembling the cover plate.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a packaging box which solves the above-mentioned problems, makes it easier to assemble a cover plate, and enables the strength of the cover plate to be increased. [Means for solving the problem]

[0006] In order to solve the above problem, the first invention is a packaging box comprising a body formed into a cylindrical shape by front and rear end walls and left and right side walls, and a cover plate provided at one of the upper and lower openings of the body. The cover plate has left and right side flaps respectively connected to one of the upper and lower edges of the both side walls, and front and rear end flaps respectively connected to one of the upper and lower edges of the both end walls. A recess is formed at the tip edge of each of the both side flaps, and a connecting opening is formed by both of the recesses of the both side flaps. The tips of the both end flaps are inserted into the connecting opening from the outside, and at least a part of the tips of the both end flaps are overlapped within the connecting opening. A first slit is formed in the end flap recessed from the left and right edge, and the first slit is engaged with the edge of the recess.

[0007] In order to solve the above problem, the second invention is a packaging box comprising a body formed into a cylindrical shape by front and rear end walls and left and right side walls, and a cover plate provided at one of the upper and lower openings of the body. The cover plate has left and right side flaps respectively connected to one of the upper and lower edges of the both side walls, and front and rear end flaps respectively connected to one of the upper and lower edges of the both end walls. A recess is formed at each of the leading edge portions of the both side flaps, and a connecting opening is formed by both of the recesses of the both side flaps. The leading ends of the both end flaps are inserted into the connecting opening from the outside, and at least a part of the leading ends of the both end flaps are separated from each other within the connecting opening. A first slit recessed from the left and right edge is formed in the end flap, and the first slit is engaged with the edge of the recess.

[0008] When assembling the cover plate of the packaging box of the present invention, the end flaps push the side flaps from the outside toward the inside of the body, widening the connecting opening in the left-right direction while allowing the tips of the end flaps to enter the connecting opening. Then, when the side flaps are returned to their flat state, the first notches of the end flaps are engaged with the edges of the recessed portions.

[0009] In the packaging box of the present invention, the connecting opening is not entirely blocked before the end flap is inserted into the connecting opening, so that the tip of the end flap can be easily inserted into the connecting opening when assembling the cover plate. Then, the first notch of the end flap is engaged with the edge of the recess, so that the end flap and the side flap are reliably connected to each other.

[0010] In the packaging box of the present invention, the first notch of the end flap engages with the edge of the recessed portion, making it difficult for the tip of the end flap to slip out of the connecting opening, thereby increasing the strength of the cover plate.

[0011] In the packaging box of the first invention, at least a portion of the tip ends of the end flaps overlap each other within the connecting opening, so that the connecting opening can be securely closed and the strength of the cover plate can be increased. Alternatively, one of the left and right portions of the tip of one of the front and rear end flaps may be overlapped with the inner surface of the tip of the other of the front and rear end flaps, and the other of the left and right portions of the tip of the other of the front and rear end flaps may be overlapped with the inner surface of the tip of the other of the front and rear end flaps. In this manner, the tips of the both end flaps can be meshed with each other, thereby reliably connecting the both end flaps to each other. Furthermore, when the entire tip edge of one of the front and rear end flaps is overlapped on the inner surface of the tip of the other front and rear end flap, the tips of both end flaps can be easily overlapped.

[0012] In the packaging box of the second invention, at least a part of the tip ends of the end flaps are separated from each other within the connecting opening to form an opening in the cover plate. This allows the length of the end flaps to be shortened, so that the area of ​​the sheet used to manufacture the blank sheet can be reduced. In addition, compared to the case where openings such as drainage holes and ventilation holes are punched into the cover plate during the manufacture of the blank sheet, the area of ​​the sheet used can be reduced and punching waste during manufacturing can be reduced. The opening area of ​​the opening can be adjusted by separating the entire tip portions of the both end flaps or by separating only a portion of the tip portions of the both end flaps.

[0013] In the above-mentioned packaging box, it is preferable to form a first notch recessed from the left-right edge of the end flap, and to position the base end side edge of the end flap in the first notch so that the outer left-right end is closer to the tip of the end flap than the inner end. In this configuration, when the end flap and the side flap are assembled, the area over which the base end edge of the end flap overlaps with the inner surface of the side flap is increased, allowing the end flap and the side flap to be securely interlocked.

[0014] In the packaging box described above, it is preferable that a protrusion protruding inward in the left-right direction is formed on an outer edge in the left-right direction of the recess. In this configuration, the protruding portions of the side flaps are pressed against the outer surfaces of the end flaps, making it difficult for the tips of the end flaps to come out of the connecting opening.

[0015] In the above-mentioned packaging box, it is preferable that a convex portion protruding inward in the left-right direction is formed in the center in the front-to-rear direction of the tip edge of the protrusion, and the convex portion is abutted against the lower surface of the end flap. In this configuration, the area pressed against the underside of the end flap is increased, making it difficult for the tip of the end flap to come out of the connecting opening.

[0016] In the above-mentioned packaging box, the first notch is configured to engage with the second notch formed on the edge of the recessed portion, thereby enabling the end flap and the side flap to be securely connected to each other.

[0017] In the above-mentioned packaging box, it is preferable that a protrusion protruding inward in the left-right direction is formed on the outer edge of the recess in the left-right direction, and the second notch is formed between the front-to-rear edge of the recess and the front-to-rear edge of the protrusion. In this configuration, the second notch can be formed deep, so that the first notch of the end flap and the second notch of the side flap can be reliably engaged with each other.

[0018] In the packaging box described above, the left-right width of the tip of the end flap can be made smaller than the left-right width of the base end, making it easier to insert the tip of the end flap into the connecting opening.

[0019] In the above-mentioned packaging box, if the front-to-rear edge of the recess is inclined toward the outside in the front-to-rear direction of the cover plate as it moves from the outer end in the left-to-right direction to the inner end, it becomes easier to insert the tip of the end flap into the connecting port.

[0020] In the packaging box, an inclined wall inclined with respect to the end wall and the side wall may be provided between at least one of the adjacent end walls and side walls. With this configuration, in a packaging box having a polygonal cylindrical body such as a hexagon or octagon, the lid plate can be easily assembled and the strength of the lid plate can be increased. Effect of the Invention

[0021] In the packaging box of the present invention, when assembling the cover plate, the tips of the end flaps can be simply inserted into the connecting openings of the side flaps to securely connect the end flaps and the side flaps, thereby increasing the strength of the cover plate. [Brief description of the drawings]

[0022] [Figure 1] 1 is a perspective view of a packaging box according to a first embodiment of the present invention, viewed from the lower front left. FIG. [Diagram 2] 1 is a diagram showing a blank sheet for a packaging box according to a first embodiment of the present invention. FIG. [Diagram 3] FIG. 2 is a bottom view of the packaging box according to the first embodiment of the present invention. [Figure 4]1 is a bottom view showing a state before the front and rear end flaps are closed in the packaging box according to the first embodiment of the present invention. FIG. [Diagram 5] 2 is a cross-sectional view of a bottom cover plate of a packaging box according to the first embodiment of the present invention, viewed from above. [Figure 6] FIG. 11 is a diagram showing a blank sheet for a packaging box according to a second embodiment of the present invention. [Figure 7] 6 is a cross-sectional view of a bottom cover plate of a packaging box according to a second embodiment of the present invention, viewed from above. [Figure 8] 13A and 13B are diagrams showing a blank sheet of a modified example of the packaging box according to the second embodiment of the present invention. [Figure 9] FIG. 11 is a diagram showing a blank sheet for a packaging box according to a third embodiment of the present invention. [Figure 10] 11 is a cross-sectional view of a bottom cover plate of a packaging box according to a third embodiment of the present invention, viewed from above. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] 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 description of each embodiment, the same components are denoted by the same reference numerals, and duplicate descriptions will be omitted. In the following description, the front, rear, left and right directions are set for the sake of convenience in describing the packaging box of this embodiment, and do not limit the configuration or usage state of the packaging box.

[0024] [First embodiment] As shown in FIG. 1, the packaging box 1A of the first embodiment comprises a body 10 formed in a rectangular cylindrical shape, an upper cover plate 20 (top plate) provided at an upper opening of the body 10, and a lower cover plate 30 (bottom plate) provided at a lower opening of the body 10.

[0025] 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. 2. The blank sheet S1 shown in Fig. 2 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 be formed with intermittent cuts. In this way, it becomes easier to fold the blank sheet S1 at the creases. Alternatively, the folded line may be formed by forming a half-cut slit only on the surface of the sheet or a slit penetrating the sheet in an intermittent linear fashion.

[0026] 1, 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 front and rear end walls 11, 11 and the left and right side walls 12, 12 are formed in a rectangular shape. In the first embodiment, as shown in Fig. 2, a strip-shaped joint piece 13 is connected to the right edge portion of the front end wall 11. As shown in Fig. 5, the joint piece 13 is attached to the inner surface of the right side wall 12.

[0027] When the blank sheet S1 (see Figure 2) is folded along each fold line and the joining piece 13 is joined to the inner surface of the right 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. In the body 10 of the first embodiment, the length in the left-right direction of the end wall 11 is greater than the length in the front-rear direction of the side wall 12, and the upper and lower openings of the body 10 are rectangular in shape (see FIG. 1). Note that the shape of the openings of the body 10 may be a square or a shape close to a square, with the lengths in the front-rear direction and the left-right direction being the same or similar.

[0028] 2, the top cover plate 20 includes a pair of front and rear first flaps 21, 21 connected to the upper edges of the front and rear end walls 11, 11, respectively, and a pair of left and right second flaps 22, 22 connected to the upper edges of the left and right side walls 12, 12, respectively. The top cover plate 20 is formed by folding both second flaps 22, 22 inward and butting both first flaps 21, 21 against the upper surfaces of both first flaps 21, 21. Although the top cover plate 20 in the first embodiment closes the entire upper opening of the body 10, it may be formed so as to close the outer periphery of the upper opening of the body 10.

[0029] As shown in FIG. 1, the lower cover plate 30 has a pair of left and right side flaps 40, 40 connected to the lower edges of the left and right side walls 12, 12, respectively, and a pair of front and rear end flaps 50, 50 connected to the lower edges of the front and rear end walls 11, 11, respectively.

[0030] 4, the left side flap 40 covers the left side area of ​​the opening on the lower side of the torso portion 10. The right side flap 40 covers the right side area of ​​the opening on the lower side of the torso portion 10. In the first embodiment, the leading edge portions of the left and right side flaps 40, 40 are spaced apart in the left-right direction, but the leading edge portions of the left and right side flaps 40, 40 may be butted against each other.

[0031] A recess 41 is formed on the leading edge (the inner edge in the left-right direction) of the side flap 40. The recess 41 is a recess formed by depressing the center of the leading edge of the side flap 40. A connecting opening 42 is formed by the inside of both recesses 41, 41 of the left and right side flaps 40, 40 and the area between both recesses 41, 41.

[0032] The front and rear edges 41a, 41a of the recess 41 are inclined outward in the front-rear direction of the lower cover plate 30 from the outer end toward the inner end in the left-right direction. As a result, the front-rear width of the recess 41 increases from both left-right ends toward the center.

[0033] A protrusion 45 that protrudes inward in the left-right direction is formed on the outer edge in the left-right direction of the recess 41. In this manner, the protrusion 45 is formed on the bottom of the recess 41. A tip edge 45b of the protruding portion 45 is disposed within the recessed portion 41. Therefore, the protruding portions 45, 45 of the left and right recessed portions 41, 41 are disposed with an interval therebetween in the left-right direction.

[0034] A second slit 62 is formed between the front edge 41a of the recess 41 and the front edge of the protruding portion 45. In addition, a second slit 62 is also formed between the rear edge 41a of the recess 41 and the rear edge of the protruding portion 45. In this way, the connecting port 42 has second slits 62 formed on the front, rear, left and right sides.

[0035] A convex portion 47 that protrudes inward in the left-right direction is formed in the center of the tip edge portion 45b of the protrusion 45. The outer shape of the convex portion 47 is curved in an arc shape.

[0036] 3, the front end flap 50 extends rearward (toward the center in the front-to-rear direction of the lower cover plate 30) from the lower edge of the front end wall 11. The front end flap 50 is overlapped on the lower surfaces of the front portions of the side flaps 40, 40 (see FIG. 1). The rear end flap 50 extends forward (toward the center in the front-to-rear direction of the bottom cover plate 30) from the lower edge of the rear end wall 11. The rear end flap 50 is overlapped on the lower surfaces of the rear portions of the side flaps 40, 40 (see FIG. 1).

[0037] The end flap 50 is formed so that its width in the left-right direction becomes smaller from the base end edge to the tip end edge. Thus, the end flap 50 has a tip end 52 with a width in the left-right direction smaller than a base end 51 with a width in the left-right direction.

[0038] The tip 52 of the front end flap 50 is inserted into the front half of the connecting opening 42 from the outside (lower side). Also, the tip 52 of the rear end flap 50 is inserted into the rear half of the connecting opening 42 from the outside. The left and right portions of the tip 52 of the end flap 50 are overlapped on the inner surface (upper surface) of the side flap 40 on both the left and right sides of the connecting opening 42 (see FIG. 5). In this manner, the tip 52 of the end flap 50 is engaged with the inner surfaces of the both side flaps 40, 40.

[0039] The leading edge of the end flap 50 extends in the left-right direction along the lower edge of the end wall 11. An extension 53 protruding rearward is formed in the right half region of the leading edge of the front end flap 50. Also, an extension 53 protruding forward is formed in the left half region of the leading edge of the rear end flap 50.

[0040] The extension 53 of the front end flap 50 is overlapped with the inner surface (upper surface) of the right half of the tip 52 of the rear end flap 50. The extension 53 of the rear end flap 50 is overlapped with the inner surface (upper surface) of the left half of the tip 52 of the front end flap 50. In this manner, the tips 52, 52 of both end flaps 50, 50 are vertically interlocked with each other. The connecting opening 42 is closed by the front and rear end flaps 50, 50.

[0041] As shown in Fig. 4, left and right first slits 61, 61 are formed on the left and right edges of the end flap 50. The first slits 61 are recessed from the left and right edges of the end flap 50 toward the left and right center. The first slits 61 are formed in approximately the center in the front-rear direction of the left and right edges of the end flap 50. The left and right first slits 61, 61 are formed symmetrically. The left and right first slits 61, 61 form the end flap 50 such that the center in the front-rear direction is constricted. The end flap 50 is divided into a base end portion 51 and a tip end portion 52 by the first slits 61, 61 as boundaries.

[0042] In the first slit 61, the edge 61a on the base end side of the end flap 50 is disposed such that the outer end P2 in the left-right direction is closer to the tip of the end flap 50 than the inner end P1. In the first embodiment, the edge 61a on the base end side of the end flap 50 in the first slit 61 is inclined toward the tip side of the end flap 50 as it moves from the inner end P1 to the outer end P2 in the left-right direction. The opening width of the first slit 61 increases as it moves from the inner end P1 to the outer end P2 in the left-right direction.

[0043] When the tip 52 of the end flap 50 is inserted into the connecting port 42, as shown in Figure 3, the first notch 61 of the end flap 50 and the second notch 62 of the side flap 40 are interlocked, and the bottom of the first notch 61 and the bottom of the second notch 62 are in contact.

[0044] The left and right protrusions 45, 45 of the side flaps 40, 40 are overlapped on the outer surfaces of the tip ends 52, 52 of the end flaps 50, 50. The convex portions 47 formed on the protrusions 45 are overlapped on the outer surfaces of the overlapping portions of the tip ends 52, 52 of the end flaps 50, 50.

[0045] Next, a procedure for assembling the bottom cover plate 30 of the packaging box 1A will be described. First, as shown in FIG. 4, the left and right side flaps 40, 40 are folded inward of the body 10 relative to the left and right side walls 12, 12. 1, the front and rear end flaps 50, 50 are folded inward of the body 10 relative to the front and rear end walls 11, 11, and the end flaps 50, 50 are overlapped on the outer surfaces (lower surfaces) of the side flaps 40, 40. As a result, the tip portions 52 of the end flaps 50 are positioned outside (lower side) of the connecting openings 42 of the side flaps 40, 40.

[0046] When the tip ends 52, 52 of the end flaps 50, 50 are pushed toward the inside of the body 10, the end flaps 50, 50 push and tilt the side flaps 40, 40 toward the inside of the body 10. This causes the tip edges of the side flaps 40, 40 to separate from each other, and the connecting opening 42 widens in the left-right direction. Then, the tip ends 52, 52 of the end flaps 50, 50 are inserted into the connecting opening 42 and enter the inner surfaces of the side flaps 40, 40.

[0047] 5, when the side flaps 40, 40 are returned to their flat position, the tip 52 of the end flap 50 overlaps the upper surfaces of the side flaps 40, 40. This causes the tip portions 52, 52 of the end flaps 50, 50 to be locked onto the upper surfaces of the side flaps 40, 40. In addition, when the side flaps 40, 40 are returned to their flat state, the extension portion 53 of the front end flap 50 is overlapped on the inner surface of the tip portion 52 of the rear end flap 50, and the extension portion 53 of the rear end flap 50 is overlapped on the inner surface of the tip portion 52 of the front end flap 50.

[0048] As a result, the space between the front and rear end flaps 50, 50 is closed by the both end flaps 50, 50. Furthermore, when the both side flaps 40, 40 are returned to their flat state, the first notch 61 of the end flap 50 and the second notch 62 formed in the recessed portion 41 of the side flap 40 are engaged with each other.

[0049] When the tips 52, 52 of the end flaps 50, 50 are engaged with the inner surfaces of the side flaps 40, 40, the projections 45 and convex portions 47 of the side flaps 40 are pressed against the outer surfaces of the end flaps 50, 50 as shown in FIG.

[0050] In this manner, by connecting the tip ends 52, 52 of the end flaps 50, 50 to the connecting openings 42 of the side flaps 40, 40, the lower cover plate 30 is formed at the lower opening of the body 10 (see FIG. 5).

[0051] In this way, in the packaging box 1A of the first embodiment, the bottom cover plate 30 can be easily assembled without using adhesive tape or adhesive, thereby improving the work efficiency when assembling the bottom cover plate 30.

[0052] In the above-described packaging box 1A, when the bottom cover plate 30 shown in Fig. 1 is assembled, if the end flap 50 pushes the side flaps 40, 40 into the inside of the body 10, the side flaps 40, 40 are inclined and the connecting opening 42 widens in the left-right direction (a gap is formed between the tip edges of the side flaps 40, 40). In addition, the left-right width of the tip 52 of the end flap 50 is smaller than the left-right width of the base end 51. Therefore, when the bottom cover plate 30 is assembled, the tip 52 of the end flap 50 can be easily inserted into the connecting opening 42.

[0053] In addition, in the packaging box 1A of the first embodiment, as shown in Figure 4, before the end flap 50 is inserted into the connecting opening 42, the entire connecting opening 42 is not blocked, making it easy to insert the tip 52 of the end flap 50 into the connecting opening 42.

[0054] In the packaging box 1A of the first embodiment, after the tip 52 of the end flap 50 is inserted into the connecting opening 42, when the both side flaps 40, 40 are returned to a flat state as shown in FIG. 3, the first notch 61 of the end flap 50 and the second notch 62 formed on the edge of the recessed portion 41 of the side flap 40 are interlocked with each other. As a result, in the packaging box 1A of the first embodiment, the end flap 50 and the side flap 40 are securely connected, and the tip 52 of the end flap 50 is less likely to come out of the connecting opening 42, thereby increasing the strength of the bottom cover plate 30.

[0055] In the packaging box 1A of the first embodiment, in the first notch 61 of the end flap 50, the edge 61a on the base end side of the end flap 50 is positioned such that the outer end in the left-right direction is closer to the tip of the end flap 50 than the inner end. In this configuration, when the end flap 50 and the side flap 40 are assembled, the area over which the base end edge of the end flap 50 overlaps with the inner surface of the side flap 40 is increased, allowing the end flap 50 and the side flap 40 to be securely interlocked together. As a result, in the packaging box 1A, when the weight of the contents acts on the bottom cover plate 30, the end flaps 50 are less likely to come off the connecting openings, and the strength of the bottom cover plate 30 can be increased.

[0056] In the packaging box 1A of the first embodiment, the second slit 62 is formed between the front-rear edge 41a of the recessed portion 41 and the front-rear edge of the protruding portion 45 (see FIG. 4). In this configuration, the second slit 62 can be formed deep, so that the first slit 61 of the end flap 50 and the second slit 62 of the side flap 40 can be reliably engaged with each other.

[0057] In the packaging box 1A of the first embodiment, the front-to-rear edge 41a of the recessed portion 41 is inclined outward in the front-to-rear direction as it moves from the outer end in the left-to-right direction to the inner end, making it easy to insert the tip 52 of the end flap 50 into the connecting opening 42.

[0058] In the packaging box 1A of the first embodiment, the protrusions 45 and the convex portions 47 of the side flaps 40 are pressed against the lower surfaces of the end flaps 50, so that the tips 52 of the end flaps 50 are unlikely to come out of the connecting opening .

[0059] In the packaging box 1A of the first embodiment, the steps (extension direction of the flutes) of the side flaps 40 extend in the left-right direction. This increases the strength of the side flaps 40 against the force exerted when the tips 52 of the end flaps 50 press the side flaps 40 downward, making it difficult for the tips 52 of the end flaps 50 to come off.

[0060] 1, in the packaging box 1A of the first embodiment, the tips 52, 52 of the end flaps 50, 50 are overlapped with each other within the connecting opening 42, and further, the tips 52, 52 of the end flaps 50, 50 are interlocked with each other, so that the tips 52, 52 of the end flaps 50, 50 are securely connected to each other. As a result, in the packaging box 1A of the first embodiment, the connecting opening 42 can be closed and the strength of the bottom cover plate 30 can be increased.

[0061] In the packaging box 1A of the first embodiment, both convex portions 47, 47 of the left and right protrusions 45, 45 are overlapped on the outer surfaces of the overlapping portions of the tip portions 52, 52 of the both end flaps 50, 50. This makes it possible to prevent the tip portions 52, 52 of the both end flaps 50, 50 from opening up.

[0062] 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 appropriately modified without departing from the spirit of the present invention. 5, in the packaging box 1A of the first embodiment, the extensions 53 are formed in the left and right half regions of the tip edge of the end flap 50, but the extensions 53 may be formed in part of the left and right half regions of the tip edge of the end flap 50. In this case, when the tips of the front and rear end flaps 50, 50 are interlocked with each other, parts of the tip edges of both end flaps 50, 50 do not overlap but are abutted or separated from each other.

[0063] In the packaging box 1A of the first embodiment, as shown in FIG. 4, the left and right first slits 61, 61 are interlocked with the left and right second slits 62, 62, but the first slits 61 and the second slits 62 may be formed on only one of the left and right sides. Furthermore, the first slit 61 of the end flap 50 may be configured to engage with the edge of the recess 41 without forming the second slit 62 in the recess 41 .

[0064] The shapes of the end flap 50 and the connecting port 42 are not limited, and are appropriately set taking into consideration ease of assembly of the bottom cover plate 30.

[0065] In the packaging box 1A of the first embodiment, the front-rear edge of the recessed portion 41 may be inclined toward the center in the front-rear direction from the outer end toward the inner end in the left-right direction. In this case, the width of the recessed portion 41 in the front-rear direction becomes smaller from the outer side toward the center in the left-right direction, so that the tip portion 52 of the end flap 50 is less likely to come out of the connecting opening 42.

[0066] In the packaging box 1A of the first embodiment, the protrusion 45 is formed at the bottom of the recess 41 of the side flap 40, but the recess 41 does not necessarily need to have the protrusion 45 formed therein. In the packaging box 1A of the first embodiment, a convex portion 47 is formed at the center of the tip edge portion 45b of the protruding portion 45 of the recessed portion 41, but the shape of the convex portion 47 is not limited. Furthermore, the protruding portion 45 does not necessarily need to have the convex portion 47 formed thereon.

[0067] In the packaging box 1A of the first embodiment, as shown in FIG. 3, the bottom cover plate 30 is formed in a rectangular shape, but the shape of the bottom cover plate 30 is not limited thereto, and for example, the bottom cover plate 30 may be formed in a square shape.

[0068] 1, the packaging box 1A of the first embodiment has a body 10 formed into a quadrangular tubular shape, but there is no limitation on the number of corners of the body 10. For example, an inclined wall may be provided between the end wall 11 and the side wall 12 to form the body 10 into a hexagonal or octagonal tubular shape.

[0069] In the first embodiment, the cover plate of the present invention is applied to the lower cover plate 30 (bottom plate) of the packaging box 1A, but the cover plate of the present invention may also be applied to the upper cover plate 20 (top plate) of the packaging box 1A.

[0070] In the packaging box 1A of the first embodiment, the top cover plate 20 is provided, but the top cover plate 20 may not be provided and the upper opening of the body 10 may be formed in a tray shape that is open.

[0071] Although the packaging box 1A of the first embodiment is made of corrugated cardboard, the packaging box of the present invention can be formed from various known paperboards.

[0072] [Second embodiment] Next, a packaging box 1B of a second embodiment will be described. As shown in Fig. 7, the packaging box 1B of the second embodiment has a substantially similar configuration to the packaging box 1A of the first embodiment (see Fig. 3), but the configuration of the tip 52 of the end flap 50 is different.

[0073] The packaging box 1B of the second embodiment is formed by mountain-folding or valley-folding a blank sheet S2 made of corrugated board shown in Fig. 6 at each fold line. The blank sheet S2 shown in Fig. 6 is arranged so that the inner side is visible.

[0074] 7, in the packaging box 1B of the second embodiment, the entire leading edge of the leading end 52 of the front end flap 50 is overlapped with the inner surface of the leading end 52 of the rear end flap 50. Also, the entire leading edge of the leading end 52 of the rear end flap 50 is overlapped with the outer surface of the leading end 52 of the front end flap 50.

[0075] In the packaging box 1B of the second embodiment, the tip ends 52, 52 of the both end flaps 50, 50 can be easily overlapped with each other.

[0076] The above describes the second embodiment of the present invention. However, the present invention is not limited to the second embodiment, and similarly to the first embodiment, it can be modified appropriately without departing from the spirit of the present invention. 7, in the packaging box 1B of the second embodiment, the entire leading edge of one end flap 50 is overlapped with the leading edge 52 of the other end flap 50, but a part of the leading edge of one end flap 50 may be overlapped with the leading edge 52 of the other end flap 50. In this case, parts of the leading edges of both end flaps 50, 50 do not overlap but are abutted against each other or spaced apart.

[0077] In the packaging box 1B of the second embodiment, the number of corners of the body 10 is not limited. For example, as shown in the blank sheet S4 in Fig. 8, an inclined wall 14 may be provided between the end wall 11 and the side wall 12 to form the body 10 into a hexagonal cylindrical shape.

[0078] [Third embodiment] Next, a packaging box 1C of a third embodiment will be described. As shown in Fig. 10, the packaging box 1C of the third embodiment has a substantially similar configuration to the packaging box 1A of the first embodiment (see Fig. 3), but the configuration of the tip 52 of the end flap 50 is different.

[0079] The packaging box 1C of the third embodiment is formed by mountain-folding or valley-folding a cardboard blank sheet S3 shown in Fig. 9 at each fold line. The blank sheet S3 shown in Fig. 9 is arranged so that the inner side is visible.

[0080] In a packaging box 1C of the third embodiment, the tip ends 52, 52 of the both end flaps 50, 50 are spaced apart from each other in the front-rear direction within the connecting opening 42, as shown in FIG. In this configuration, the tip ends 52, 52 of the end flaps 50, 50 are separated from each other, so that an opening is formed in the center of the bottom cover plate 30. This allows the length of the end flaps 50 to be shortened, thereby reducing the area of ​​the sheet used to manufacture the blank sheet S3 (see FIG. 9). Also, compared to the case where openings such as drainage holes and ventilation holes are punched into the end flaps 50 or the side flaps 40 during the manufacture of the blank sheet S3 (see FIG. 9), the area of ​​the sheet used can be made smaller and punching waste during manufacturing can be reduced.

[0081] Although the third embodiment of the present invention has been described above, the present invention is not limited to the third embodiment, and similarly to the first embodiment, it can be appropriately modified without departing from the spirit of the present invention. In the packaging box 1C of the third embodiment, as shown in Fig. 10, the entire tips of the front and rear end flaps 50, 50 are spaced apart, but parts of the tips of both end flaps 50, 50 may be spaced apart. In this case, parts of the tips of both end flaps 50, 50 are butted together or overlapped without being spaced apart. [Explanation of symbols]

[0082] 1A Packaging box (first embodiment) 1B Packaging box (second embodiment) 1C Packaging box (third embodiment) 10. Torso 11 End Wall 12 Side wall 13 Joint piece 14 Slanted wall 20 Top cover plate 21 First flap 22 Second flap 30 Lower cover plate 40 Side flap 41 Recess 42 Connection port 45 Protrusion 47 Convex 50 End flap 51 Proximal end 52 Tip 53 Extension 61 First cut 62 Second cut P1 inner end P2 outer end S1 Blank sheet (first embodiment) S2 Blank sheet (second embodiment) S3 Blank sheet (third embodiment) S4 Blank sheet (modification of the second embodiment)

Claims

1. A body formed in a cylindrical shape by front and rear end walls and left and right side walls, The body comprises a cover plate provided at one of the upper or lower openings, The aforementioned cover plate is Left and right side flaps are provided connected to one of the upper and lower edges of the aforementioned side walls, It has front and rear end flaps connected to one of the upper and lower edges of the aforementioned end walls, Recesses are formed at the leading edges of the aforementioned side flaps. The two recessed portions of the flaps on both sides form a connecting opening. The ends of the flaps at both ends are inserted into the connecting opening from the outside. Within the connecting opening, at least a portion of the tip portions of the flaps at both ends are overlapped. The end flap has a first indentation formed in the left-right edge, The first notch is engaged with the edge of the recessed portion, On the outer edges of the recessed portion in the left-right direction, protrusions are formed that project inward in the left-right direction. The tip edge of the aforementioned protrusion is formed in a straight line in the front-rear direction. At the center of the front-to-back edge of the aforementioned protruding portion, a convex portion is formed that protrudes inward in the left-to-right direction. A packaging box characterized in that the protruding portion and the convex portion are superimposed on the outer surface of the tip portions of the flaps at both ends.

2. A packaging box according to claim 1, One of the front and rear end flaps has one side of its tip that overlaps with the inner surface of the other front and rear end flap. A packaging box characterized in that the left and right portions of the tip of the front and rear end flaps overlap the inner surface of the tip of one of the front and rear end flaps.

3. A packaging box according to claim 1, A packaging box characterized in that the entire leading edge of one of the front and rear end flaps is superimposed on the inner surface of the leading edge of the other front and rear end flap.

4. A body formed in a cylindrical shape by front and rear end walls and left and right side walls, The body comprises a cover plate provided at one of the upper or lower openings, The aforementioned cover plate is Left and right side flaps are provided connected to one of the upper and lower edges of the aforementioned side walls, It has front and rear end flaps connected to one of the upper and lower edges of the aforementioned end walls, Recesses are formed at the leading edges of the aforementioned side flaps. The two recessed portions of the flaps on both sides form a connecting opening. The ends of the flaps at both ends are inserted into the connecting opening from the outside. Within the connecting opening, at least a portion of the tips of the flaps at both ends are separated from each other. The end flap has a first indentation formed in the left-right edge, The first notch is engaged with the edge of the recessed portion, On the outer edges of the recessed portion in the left-right direction, protrusions are formed that project inward in the left-right direction. The tip edge of the aforementioned protrusion is formed in a straight line in the front-rear direction. At the center of the front-to-back edge of the aforementioned protruding portion, a convex portion is formed that protrudes inward in the left-to-right direction. A packaging box characterized in that the protruding portion and the convex portion are superimposed on the outer surface of the tip portions of the flaps at both ends.

5. The packaging box according to claim 4, A packaging box characterized in that the entire tips of the flaps at both ends are spaced apart.

6. A packaging box according to claim 1 or claim 4, A packaging box characterized in that, in the first cut, the base end edge of the end flap has its left-right outer end positioned closer to the tip of the end flap than its inner end.

7. A packaging box according to claim 1 or claim 4, A packaging box characterized in that the first notch engages with a second notch formed on the edge of the recessed portion.

8. The packaging box according to claim 7, A packaging box characterized in that the second notch is formed between the front-to-rear edge of the recessed portion and the front-to-rear edge of the protruding portion.

9. A packaging box according to claim 1 or claim 4, A packaging box characterized in that the width of the tip of the end flap in the left-right direction is smaller than the width of the base end in the left-right direction.

10. A packaging box according to claim 1 or claim 4, A packaging box characterized in that the front-to-back edges of the recessed portion are inclined outward in the front-to-back direction on the lid plate as they move from the outer end in the left-to-right direction towards the inner end.

11. A packaging box according to claim 1 or claim 4, A packaging box characterized in that an inclined wall is provided between at least one adjacent end wall and side wall, inclined with respect to the end wall and the side wall.

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