Cardboard box and blank sheet

Abstract

To provide a corrugated fiberboard box which can be neatly folded.SOLUTION: A planar shape of the side peripheral portions 50 in an assembled state is a polygonal shape that is inscribed in a virtual rectangle, in which a pair of sides facing each other are each in contact with the rectangle over the entire length, and gaps between four corners of the rectangle and the planar shape are each a triangle, and circumferential lengths of two surfaces 51 and 52 facing each other are equal to each other in a state where a top surface portion and a bottom surface portion of the cardboard box are open and the side peripheral portions 50 are folded in two.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a corrugated cardboard box and a blank sheet. [Background technology]

[0002] A commonly known type of corrugated cardboard box has surface-bonded joints and a series of loops around the sides. One such cardboard box has a side periphery that is octagonal in plan view when assembled (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Registered Utility Model No. 3050202 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the cardboard box of Patent Document 1 is opened with the top and bottom surfaces and folded in two along the sides for disposal or other reasons, the two opposing surfaces are separated from each other (floating). In other words, the box cannot be folded neatly. This results in a cardboard box that is bulky (thick) when folded, and this bulkiness becomes particularly noticeable when multiple cardboard boxes are stacked.

[0005] Therefore, the inventors of the present application recognized that there was a need for a cardboard box that could be folded neatly, in other words, a cardboard box that could reduce the distance between the two opposing surfaces when the top and bottom surfaces were opened and the side periphery was folded in two for disposal or the like, and preferably so that the two opposing surfaces were in surface contact with each other.

[0006] The present invention has been made in view of the above-mentioned problems, and provides a cardboard box and a blank sheet that can be folded neatly. [Means for solving the problem]

[0007] According to the present invention, a corrugated cardboard box is provided in which the joint portion is surface-bonded and the side periphery is a continuous loop, The planar shape of the side periphery of the assembled cardboard box is a polygon inscribed in an imaginary rectangle, with each pair of opposing sides contacting the rectangle over their entire length, and with the gaps between the four corners of the rectangle and the planar shape forming triangles, The cardboard box is provided such that when the top and bottom surfaces of the cardboard box are open and the side periphery is folded in two, the circumferential length dimensions of the two opposing faces are equal to each other.

[0008] According to the present invention, there is also provided a corrugated cardboard box in which the joint portions are surface-bonded and the side periphery is a continuous loop, The planar shape of the side periphery of the cardboard box in an assembled state is octagonal or hexagonal, The cardboard box is provided such that when the top and bottom surfaces of the cardboard box are open and the side periphery is folded in two, the circumferential length dimensions of the two opposing faces are equal to each other.

[0009] According to the present invention, there is also provided a blank sheet for a cardboard box, comprising: A side periphery forming portion that forms a side periphery of the cardboard box in an assembled state is provided, The side periphery constituent portion is a first intended joining portion and a second intended joining portion that are surface-joined to each other to form a joint portion; A first surface adjacent to the first intended joining portion with a first ruled line interposed therebetween; A second surface adjacent to the second intended joining portion with a second ruled line interposed therebetween; a third surface facing the first surface in the assembled state; a fourth surface facing the second surface in the assembled state; Including, A blank sheet is provided in which the first side and the third side have the same length in the circumferential direction, and the second side and the fourth side have the same length. [Effects of the Invention]

[0010] According to the present invention, it is possible to fold a cardboard box neatly. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a perspective view of an assembled cardboard box according to a first embodiment. FIG. [Figure 2] 1 is a plan view of an assembled cardboard box according to a first embodiment. [Figure 3] 1 is a side view of the assembled cardboard box according to the first embodiment. FIG. [Figure 4] 1 is a plan view of the assembled cardboard box according to the first embodiment, showing only the side periphery. FIG. [Figure 5] 1 is a plan view (developed view) of a blank sheet that will become a cardboard box according to a first embodiment. [Figure 6] FIG. 2 is a diagram showing the state in which the cardboard box according to the first embodiment is folded in two, showing only the side periphery. [Figure 7] FIG. 10 is a plan view of the assembled cardboard box according to the second embodiment. [Figure 8] FIG. 10 is a plan view (developed view) of a blank sheet that will become a cardboard box according to a second embodiment. [Figure 9] FIG. 10 is a plan view of the assembled cardboard box according to the first modification, showing only the side periphery. [Figure 10] FIG. 10 is a plan view of the assembled cardboard box according to the second modification, showing only the side periphery. [Figure 11] FIG. 10 is a plan view of the assembled cardboard box according to Modification 3, showing only the side periphery. [Figure 12] FIG. 10 is a plan view of the assembled cardboard box according to the fourth modification, showing only the side periphery. [Figure 13] FIG. 10 is a plan view of the assembled cardboard box according to the fifth modification, showing only the side periphery. [Figure 14] FIG. 10 is a diagram showing a state in which a cardboard box according to a comparative embodiment is folded in two, showing only the side periphery. [Figure 15] FIG. 10 is a plan view (developed view) of a blank sheet that will become a cardboard box according to a comparative embodiment. [Figure 16] FIG. 10 is a plan view of an assembled cardboard box according to a comparative embodiment, showing only the side periphery. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments and modifications of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and the description thereof will be omitted as appropriate. In this specification, unless otherwise specified, the explanations of the positional relationships (upper and lower relationships, etc.) of the components of the cardboard box 100 and the blank sheet 200 refer to the positional relationships when the cardboard box 100 is assembled as shown in Figures 1 to 3, with the top surface 60 on the upper side and the bottom surface 70 on the lower side, and the positional relationships in these explanations do not necessarily coincide with the positional relationships before, during, or when the cardboard box 100 is assembled or in use. In addition, the positional relationship of each component of the cardboard box 100 and the blank sheet 200 may be explained in each drawing. The terms "vertical," "horizontal," "perpendicular," and "parallel" used herein include the range of error acceptable in the technical field to which the present invention pertains. For example, unless otherwise specified, the terms "vertical," "horizontal," "perpendicular," and "parallel" used herein mean a deviation of less than ±10° from the strict vertical direction, the strict horizontal direction, the strict perpendicular direction, or the strict parallel direction. The deviation from the strict vertical direction, the strict horizontal direction, the strict perpendicular direction, or the strict parallel direction is preferably ±5° or less, and more preferably ±3° or less.

[0013] [First embodiment] First, the first embodiment will be described with reference to FIGS. The cardboard box 100 according to this embodiment is a cardboard box 100 in which the joint portions 19 are surface-jointed and the side periphery portions 50 form a continuous loop. As shown in FIG. 4 , the shape of the side periphery 50 in a planar view of the assembled cardboard box 100 is a polygon inscribed in an imaginary rectangle (rectangle) 80, with each pair of opposing sides contacting the rectangle 80 along its entire length, and gaps 81a, 82a, 83a, and 84a between the four corners 81, 82, 83, and 84 of the rectangle 80 and the shape in the planar view form triangles. In this embodiment, opposing sides 31 and 35 contact the rectangle 80 along their entire length, and opposing sides 33 and 37 contact the rectangle 80 along their entire length. In other words, two pairs of opposing sides contact the rectangle 80 along their entire length. Here, gap 84a where the joint portion 19 is located is considered to have no step on the outer surface of the joint portion 19, and for convenience, it is considered to be triangular (like the other gaps 81a, 82a, and 83a). When the top surface 60 and bottom surface 70 of the cardboard box 100 are open and the side peripheral portion 50 is folded in two (Figure 6), the circumferential length dimensions of the two opposing surfaces (surfaces 51 and 52 shown in Figure 6) are equal to each other. In other words, the circumferential length dimension of surface 51 (the sum of length dimensions W2, W1, W8, and W7 shown in FIG. 4) and the circumferential length dimension of surface 51 (the sum of length dimensions W3, W4, W5, and W6 shown in FIG. 4) are equal to each other. Here, "the circumferential length dimensions of the two opposing surfaces are equal to each other" means that the difference in the circumferential length dimensions of the two opposing surfaces is preferably ±5 mm or less, more preferably ±4 mm or less, even more preferably ±3 mm or less, and even more preferably ±2 mm or less. 6, side periphery 50 is folded at two locations, namely, at the position of crease L5 and the position of crease L13, of the multiple creases (eight in this embodiment) on side periphery 50, and is stretched without being folded at the other creases (crease lines L3, L1, L15, L7, L9, and L11, which will be described later), so that two portions of side periphery 50 located between crease L5 and crease L13, i.e., faces 51 and 52, are brought close to or in contact with each other. Therefore, the folding direction is the direction in which faces 51 and 52 are brought close to each other.

[0014] According to this embodiment, when the top surface 60 and bottom surface 70 of the cardboard box 100 are open and the side periphery 50 is folded in two, the circumferential lengths of the two opposing surfaces (surfaces 51, 52) are equal to each other. Therefore, when the side periphery 50 is folded in two, the distance between the two opposing surfaces (surfaces 51, 52) can be reduced, and the two opposing surfaces can be brought into surface contact with each other, as shown in FIG. 6, for example. In other words, the cardboard box 100 can be folded neatly. Therefore, the bulkiness of the cardboard box when folded in two (bulkiness of the cardboard box in the direction in which the surfaces 51, 52 face each other) can be reduced. Furthermore, when the cardboard box 100 is assembled, the planar shape of the side periphery 50 is inscribed in an imaginary rectangle 80, with each pair of opposing sides contacting the rectangle 80 along their entire length, and the gaps 81a, 82a, 83a, 84a between the four corners 81, 82, 83, 84 of the rectangle 80 and the planar shape are each triangular, forming a polygon, so that the cardboard box 100 can be placed in a rectangular space comfortably.

[0015] 4, the planar view shape includes a first side (side 31) that is one of a pair of sides, a second side (side 38) that is adjacent to the first side and includes joint portion 19, and a third side (side 32) that is adjacent to the first side on the opposite side to the second side. Here, the fact that the third side is adjacent to the first side on the opposite side to the second side means that the third side is adjacent (to the first side) on the opposite side to the direction in which the second side is adjacent to the first side in the circumferential direction of loop-shaped side peripheral portion 50. The angle θ11 between the first side and the second side and the angle θ12 between the first side and the third side are different from each other. By adopting such a configuration, it is possible to easily realize a structure in which the circumferential length dimensions of the two opposing faces (faces 51, 52) are equal to each other when the top face 60 and bottom face 70 of the cardboard box 100 are open and the side periphery 50 is folded in two. Here, the angle θ11 and the angle θ12 being different from each other means that the difference between the angle θ11 and the angle θ12 is 1° or more, and the difference between the angle θ11 and the angle θ12 is preferably 2° or more, and more preferably 3° or more. In this embodiment, the angle θ12 is 135°, while the angle θ11 is approximately 139°, and the difference between the angles θ11 and θ12 is approximately 4°. In addition, in this embodiment, in the above-described planar view shape, all of the interior angles of the side peripheral portion 50 other than the angle θ11 are 135°.

[0016] Here, the side periphery portion 50 has a polygonal shape (octagonal, hexagonal, etc.) in a plan view in the assembled state. That is, in the assembled state, the side periphery portion 50 has a rectangular cylindrical shape and has a plurality of side surfaces. The circumferential direction (the direction of arrow R shown in FIG. 5) is the direction around the axis of the side circumferential portion 50 in the assembled state, the direction along the side surface, and also the direction in which the multiple side surfaces are arranged. The axial direction of the side peripheral portion 50 in the assembled state may be referred to as the up-down direction. In particular, the direction toward the top surface portion 60 in the assembled state may be referred to as the up (upper side), and the direction toward the bottom surface portion 70 in the assembled state may be referred to as the down (lower side). Furthermore, the direction perpendicular to the vertical direction may be referred to as the horizontal direction. In the assembled state, the top surface portion 60 is disposed on one side (upper side) in the axial direction of the side peripheral portion 50, and the bottom surface portion 70 is disposed on the other side (lower side) in the axial direction of the side peripheral portion 50. In the assembled state, it is preferable that each of the top surface portion 60 and the bottom surface portion 70 has a planar shape that is perpendicular to the axial direction of the side peripheral portion 50. The cardboard box 100 only needs to have at least one of the top surface 60 and the bottom surface 70. From the viewpoint of structural stability, it is preferable that the cardboard box 100 has both the top surface 60 and the bottom surface 70 as its actual body, and this is also the case in this embodiment. However, by having at least one of the top surface portion 60 and the bottom surface portion 70 as a substance, the cardboard box 100 can maintain its shape in an assembled state. When the cardboard box 100 has only the bottom surface portion 70 of the top surface portion 60 and the bottom surface portion 70 as a substance, the top surface portion 60 is an opening on one side of the side peripheral portion 50 in the axial direction. Similarly, when the cardboard box 100 has only the top surface portion 60 of the top surface portion 60 and the bottom surface portion 70 as a substance, the bottom surface portion 70 is an opening on one side of the side peripheral portion 50 in the axial direction.

[0017] The cardboard box 100 referred to here includes the assembled state shown in Figures 1 to 3, the state before being assembled, and the state in which the top surface 60 and bottom surface 70 are opened for disposal or the like. In the assembled state, the plurality of flaps constituting the top surface 60 (in the present embodiment, flaps 21, 22, 23, and 24 shown in FIG. 5 ) are joined to one another, and the plurality of flaps constituting the bottom surface 70 (in the present embodiment, flaps 25, 26, 27, and 28 shown in FIG. 5 ) are joined to one another. Before the assembled state, the first intended joining portion 19a and the second intended joining portion 19b shown in FIG. 5 are surface-joined to one another to form the joint portion 19 ( FIG. 4 ), and the side periphery 50 forms a series of loops, but the plurality of flaps constituting the top surface 60 and the plurality of flaps constituting the bottom surface 70 are unjoined. Furthermore, by peeling the plurality of flaps constituting the top surface 60 and the plurality of flaps constituting the bottom surface 70 of the assembled cardboard box 100 from one another, the top surface 60 and the bottom surface 70 can be opened. The side periphery 50 has a joint portion 19 at one or more locations in the circumferential direction. In this embodiment, other embodiments, and modified examples, the cardboard box 100 has a joint portion 19 at one location in the circumferential direction of the side periphery 50, but the present invention is not limited to this example, and the side periphery 50 may have a joint portion 19 at two or more locations in the circumferential direction. The items to be contained in the cardboard box 100 are not particularly limited, but examples include items that have a circular shape in plan view, such as a bottle, or items that have an oval shape in plan view, such as a tube (laminated tube, etc.).

[0018] Furthermore, the cardboard box 100 according to this embodiment is a cardboard box 100 in which the joint portions 19 are surface-jointed and the side periphery portions 50 form a continuous loop, and the planar shape of the side periphery portions 50 of the cardboard box 100 in its assembled state is octagonal or hexagonal, and when the top surface portion 60 and bottom surface portion 70 of the cardboard box 100 are open and the side periphery portions 50 are folded in two, the circumferential length dimensions of the two opposing faces are equal to each other. Here, "the circumferential length dimensions of the two opposing surfaces are equal to each other" means that the difference in the circumferential length dimensions of the two opposing surfaces is preferably ±5 mm or less, more preferably ±4 mm or less, even more preferably ±3 mm or less, and even more preferably ±2 mm or less. In this embodiment, the "folded in two" state refers to a state in which, for example, as shown in Fig. 6, of the multiple (eight in this embodiment) creases on side periphery 50, side periphery 50 is folded at two locations, namely, crease L5 and crease L13, as described below, and side periphery 50 is left unfolded at the other creases (crease L3, L1, L15, L7, L9, and L11, as described below), so that two portions of side periphery 50 located between crease L5 and crease L13, i.e., faces 51 and 52, are brought close to or abut against each other. Therefore, the folding direction is the direction in which faces 51 and 52 come close to each other. According to this embodiment, when the side periphery 50 is folded in two, the distance between the two opposing surfaces (surfaces 51, 52) can be reduced, and for example, as shown in Fig. 6, the two opposing surfaces can be brought into surface contact with each other. In other words, the cardboard box 100 can be folded neatly. Therefore, the bulkiness of the cardboard box when folded in two (the bulkiness of the cardboard box in the direction in which the surfaces 51, 52 face each other) can be reduced.

[0019] In addition, cardboard boxes 100 in which the side periphery 50 in an assembled state has an octagonal or hexagonal shape in plan view have the advantage of being able to reduce dead space in the interior space (compared to cardboard boxes with a square shape in plan view) when storing multiple items that are circular in plan view, such as PET bottles or wine bottles. Therefore, for example, it is possible to store items that are circular in plan view, such as PET bottles or wine bottles, with their outer surfaces abutting against the inner surfaces of the corners (places corresponding to the inclined sides) of cardboard box 100. Furthermore, cardboard boxes 100 whose side periphery 50 has an octagonal or hexagonal planar shape when assembled can improve compressive strength (pressure resistance) in the vertical direction (compared to cardboard boxes with a square planar shape, etc.), which has the advantage of improving deformation resistance when multiple cardboard boxes 100 are stacked. In addition, cardboard boxes 100 whose side periphery 50 has an octagonal or hexagonal planar shape when assembled can reduce the material area (compared to cardboard boxes with a square planar shape), which has the advantage of improving the efficiency of material (cardboard sheets) utilization.

[0020] 4, the planar view shape includes a pair of opposing sides (sides 31 and 35), a second side (side 38) that is adjacent to the first side (side 31), which is one of the pair of sides, and that includes joint portion 19, and a third side (side 32) that is adjacent to the first side on the opposite side to the second side. Here, the fact that the third side is adjacent to the first side on the opposite side to the second side means that the third side is adjacent (to the first side) on the opposite side to the direction in which the second side is adjacent to the first side in the circumferential direction of loop-shaped side peripheral portion 50. The angle θ11 between the first side and the second side and the angle θ12 between the first side and the third side are different from each other. Here, the angle θ11 and the angle θ12 being different from each other means that the difference between the angle θ11 and the angle θ12 is 1° or more, preferably 2° or more, and more preferably 3° or more. In the present embodiment, the difference between the angle θ11 and the angle θ12 is approximately 4°. By adopting such a configuration, it is possible to easily realize a structure in which the circumferential length dimensions of the two opposing faces (faces 51, 52) are equal to each other when the top face 60 and bottom face 70 of the cardboard box 100 are open and the side periphery 50 is folded in two.

[0021] This embodiment will be described in more detail below.

[0022] As shown in Figures 1 to 3, the cardboard box 100 of this embodiment comprises a side periphery 50, a top surface 60 that closes the upper opening of the side periphery 50 in the assembled state, and a bottom surface 70 that closes the lower opening of the side periphery 50 in the assembled state. 4, the shape of the side periphery portion 50 in a plan view is an octagon, and therefore the side periphery portion 50 has eight side surfaces (side surfaces 11, 12, 13, 14, 15, 16, 17, and 18).

[0023] As shown in FIG. 5, the blank sheet 200 has a side periphery forming portion 10 that forms the side periphery 50 when the cardboard box 100 is assembled. The side peripheral portion constituent portion 10 includes a plurality of side surfaces 11 to 17, and a first intended joining portion 19a and a second intended joining portion 19b that are surface-joined to each other to form a joint portion 19 (Figures 2, 3, and 4) and also form the side surface 18. Each of the side surfaces 11 to 17 is formed in a rectangular shape (for example, a rectangular shape). The side surfaces 11 to 17 are arranged in a line in this order and are connected sequentially. The first intended joining portion 19a and the second intended joining portion 19b are respectively arranged at both ends in the arrangement direction of the multiple side surfaces 11 to 17 of the periphery forming portion 10. In other words, the first intended joining portion 19a is arranged adjacent to the side surface 11 and is continuous with the side surface 11, and the second intended joining portion 19b is arranged adjacent to the side surface 17 and is continuous with the side surface 17. The first to-be-joined portion 19a and the second to-be-joined portion 19b are each formed in a rectangular shape (e.g., a rectangular shape). However, the second to-be-joined portion 19b is formed, for example, in a shape in which the corners on the side not connected to the side surface 17 are rounded. A line L1 is formed at the boundary between the first intended joining portion 19a and side surface 11, a line L3 at the boundary between side surface 11 and side surface 12, a line L5 at the boundary between side surface 12 and side surface 13, a line L7 at the boundary between side surface 13 and side surface 14, a line L9 at the boundary between side surface 14 and side surface 15, a line L11 at the boundary between side surface 15 and side surface 16, a line L13 at the boundary between side surface 16 and side surface 17, and a line L15 at the boundary between side surface 17 and side surface 18. These ruled lines L1, L3, L5, L7, L9, L11, L13, and L15 each extend in the vertical direction. The first intended joining portion 19a and the second intended joining portion 19b are brought into surface contact so that portions of them overlap in the circumferential direction, and are surface-joined by adhesive or the like, thereby forming a joint portion 19 and causing the side periphery forming portion 10 to become a continuous loop of side periphery 50, resulting in the cardboard box 100 in an unassembled state. Note that the joint portion 19 does not constitute the entire side surface 18, but rather the portion of the side surface 18 where the first intended joining portion 19a and the second intended joining portion 19b overlap in the circumferential direction. Thus, the joint portion 19 constitutes a portion of the side surface 18 in the circumferential direction.

[0024] The blank sheet 200 includes a side peripheral portion forming portion 10 as well as a plurality of flaps. More specifically, the blank sheet 200 includes a plurality of flaps (e.g., a total of four flaps, flaps 21, 22, 23, and 24) that constitute the top surface portion 60 in the assembled state, and a plurality of flaps (e.g., a total of four flaps, flaps 25, 26, 27, and 28) that constitute the bottom surface portion 70 in the assembled state. Of these, flap 21 is connected to the upper side of side 11, and flap 25 is connected to the lower side of side 11. Flap 22 is connected to the upper side of side 13, and flap 26 is connected to the lower side of side 13. Flap 23 is connected to the upper side of side 15, and flap 27 is connected to the lower side of side 15. Flap 24 is connected to the upper side of side 17, and flap 28 is connected to the lower side of side 17. The flaps 21 and 23 may have a tear line 61 such as a perforation formed thereon to facilitate opening the assembled cardboard box 100 and removing the contents. A line L2 is formed at the boundary between side 11 and flap 21, a line L4 at the boundary between side 11 and flap 25, a line L6 at the boundary between side 13 and flap 22, a line L8 at the boundary between side 13 and flap 26, a line L10 at the boundary between side 15 and flap 23, a line L12 at the boundary between side 15 and flap 27, a line L14 at the boundary between side 17 and flap 24, and a line L16 at the boundary between side 17 and flap 28. These ruled lines L2, L4, L6, L8, L10, L12, L14, and L16 each extend in the horizontal direction.

[0025] In this way, ruled lines are formed at the boundaries between the respective portions of the blank sheet 200 (the side surfaces 11 to 17, the first portion to be joined 19a, the second portion to be joined 19b, and the flaps 21 to 28). Each ruled line is a linear groove formed on one surface (for example, the surface that will become the inner surface of the cardboard box 100) or on both surfaces of the cardboard that constitutes the blank sheet 200. Each part of the blank sheet 200 (each of the side surfaces 11 to 17, the first to-be-joined part 19a, the second to-be-joined part 19b, and each of the flaps 21 to 28) is formed in a flat plate shape. The blank sheet 200 (corrugated cardboard box 100) can be easily folded using the creases as folding lines.

[0026] Here, the length of the side of the cardboard box 100 is considered based on the center of the thickness of the blank sheet 200 at the location where the ruled lines extending up and down are arranged. Points P1, P2, P3, P4, P5, P6, P7, and P8 shown in Figure 4 indicate the thickness center (center position in the thickness direction) of the blank sheet 200 where the ruled lines L1, L3, L5, L7, L9, L11, L13, and L15 are formed, respectively. A length dimension W1, which is the length of the side 31 (the length of the side surface 11 in the circumferential direction), is the distance between the point P1 and the point P2. Similarly, length dimension W2, which is the length of side 32 (the length of side 12 in the circumferential direction), is the distance between point P2 and point P3, length dimension W3, which is the length of side 33 (the length of side 13 in the circumferential direction), is the distance between point P3 and point P4, length dimension W4, which is the length of side 34 (the length of side 14 in the circumferential direction), is the distance between point P4 and point P5, length dimension W5, which is the length of side 35 (the length of side 15 in the circumferential direction), is the distance between point P5 and point P6, length dimension W6, which is the length of side 36 (the length of side 16 in the circumferential direction), is the distance between point P6 and point P7, length dimension W7, which is the length of side 37 (the length of side 17 in the circumferential direction), is the distance between point P7 and point P8, and length dimension W8, which is the length of side 38 (the length of side 18 in the circumferential direction), is the distance between point P8 and point P1. Furthermore, the angle θ11 formed by the first side (side 31) and the second side (side 38) is the angle formed between the outer surface or inner surface of side surface 11, which is the side surface including the first side (side 31), and the outer surface or inner surface of side surface 18, which is the side surface including the second side (side 38), and is shown in FIG. 4 as the angle formed between the outer surface of side surface 11 and the outer surface of side surface 18. Here, the outer surface of side surface 18 is the outer surface of first to-be-joined portion 19a, which is the outer portion of first to-be-joined portion 19a and second to-be-joined portion 19b that form side surface 18. Here, the inner surface of side surface 18 is the inner surface of second to-be-joined portion 19b, which is the inner portion of first to-be-joined portion 19a and second to-be-joined portion 19b that form side surface 18. Furthermore, the angle θ12 between the first side (side 31) and the third side (side 32) is the angle between the outer or inner surface of side 11, which is the side that includes the first side (side 31), and the outer or inner surface of side 12, which is the side that includes the third side (side 32), and in Figure 4 is shown as the angle between the outer surface of side 11 and the outer surface of side 12.

[0027] The first intended joining portion 19a at one end of the side periphery constituent portion 10 and the second intended joining portion 19b at the other end are surface-joined (for example, glued) to form the joint portion 19, so that the side periphery constituent portion 10 becomes a series of loops (annular), that is, a series of loop-shaped side periphery portions 50 are formed. By forming the series of loop-shaped side periphery portions 50 in this way, the blank sheet 200 becomes the cardboard box 100 in an unassembled state. When the first intended joining portion 19a and the second intended joining portion 19b are surface-to-surface joined to each other, it is preferable to wrap the side periphery forming portion 10 around a mandrel (not shown) and fold each portion of the side periphery forming portion 10 (the first intended joining portion 19a, the side surfaces 11-17, and the second intended joining portion 19b) along the boundary lines between them. The mandrel is formed to have the same outer shape as the internal space of the assembled cardboard box 100. Therefore, by wrapping the side periphery forming portion 10 around the mandrel and surface-to-surface joining the first intended joining portion 19a and the second intended joining portion 19b to each other, the circumferential length dimension of the side surface 18 formed by the first intended joining portion 19a and the second intended joining portion 19b can be adjusted to a desired dimension. This allows the length dimension W2, which is the length of side 32, the length dimension W4, which is the length of side 34, the length dimension W6, which is the length of side 36, and the length dimension W8, which is the length of side 38, to be equal to each other.

[0028] Furthermore, the flaps 21, 22, 23, 24 are folded perpendicularly to the side surfaces 11, 13, 15, 17 to which they are connected, and these flaps 21, 22, 23, 24 are joined together (for example, surface-joined), thereby forming the top surface portion 60. More specifically, for example, as shown in FIG. 1, the flaps 21 and 23 are inner flaps, and the flaps 22 and 24 are outer flaps that are placed on the outer sides of the inner flaps. The flap 22 is disposed across the flaps 21 and 23, overlapping the outside of the flaps 21 and 23, and is surface-bonded to the flaps 21 and 23. Similarly, the flap 24 is disposed across the flaps 21 and 23, overlapping the outside of the flaps 21 and 23, and is surface-bonded to the flaps 21 and 23. As a result, the top surface portion 60 is formed.

[0029] Similarly, the flaps 25, 26, 27, 28 are folded perpendicular to the side surfaces 11, 13, 15, 17 to which they are connected, and the flaps 25, 26, 27, 28 are joined (for example, surface-joined) to one another to form the bottom surface portion 70. More specifically, for example, flaps 26 and 28 are inner flaps, and flaps 25 and 27 are outer flaps that are placed on the outside of the inner flaps. The flap 25 is disposed across the flaps 26 and 28, overlapping the outside of the flaps 26 and 28, and is surface-bonded to the flaps 26 and 28. Similarly, the flap 27 is disposed across the flaps 26 and 28, overlapping the outside of the flaps 26 and 28, and is surface-bonded to the flaps 26 and 28. As a result, the bottom surface portion 70 is formed. A mandrel may also be used when joining the flaps 25, 26, 27, and 28 together to form the bottom portion 70.

[0030] In this way, the cardboard box 100 has a plurality of flaps that make up the top surface 60 in the assembled state, and a plurality of flaps that make up the bottom surface in the assembled state. The cardboard box 100 in the assembled state is in an assembled state by the plurality of flaps that make up the top surface 60 being joined to one another, and the plurality of flaps that make up the bottom surface being joined to one another. Here, the joining of the plurality of flaps is not limited to surface joining by adhesive, but may be joining by means of staples or the like.

[0031] In this embodiment, the shape in plan view is an octagon including four inclined sides (sides 32, 34, 36, 38) facing the four corners 81, 82, 83, 84 of the rectangle 80, respectively. Of the four inclined sides, at least one pair of inclined sides located diagonally opposite each other (diagonally opposite corners of the rectangle 80) have the same length. This makes it possible to ensure a certain degree of symmetry in the shape as viewed from above. Here, the lengths of a pair of inclined sides located diagonally opposite each other being equal means that the difference in the lengths of the pair of inclined sides is preferably ±1.3% or less, more preferably ±1.0% or less, even more preferably ±0.7% or less, and even more preferably ±0.5% or less.

[0032] The length of the inclined sides (sides 32, 34, 36, 38) can be set according to the size of the contents to be stored, so there are no particular limitations, but it is preferably between 40 mm and 80 mm. By setting the length of the inclined side to 40 mm or more and 80 mm or less, a bottle with a capacity of 500 ml, for example, can be suitably accommodated in the cardboard box 100.

[0033] The shape in plan view includes a pair of opposing sides, the pair of sides having equal lengths and facing parallel to each other. By adopting such a configuration, the symmetry of the shape of the cardboard box 100 in plan view can be ensured. Here, the lengths of a pair of opposing sides being equal to each other means that the difference in the lengths of the pair of sides is preferably ±1.3% or less, more preferably ±1.0% or less, even more preferably ±0.7% or less, and even more preferably ±0.5% or less. In this embodiment, sides 31 and 35 have the same length (i.e., length dimension W1 of side 31 and length dimension W5 of side 35 are equal), and are parallel and opposed to each other. Furthermore, the sides 33 and 37 have the same length (that is, the length W3 of the side 33 and the length W7 of the side 37 are equal to each other), and are parallel to each other and face each other. Furthermore, the sides 32 and 36 have the same length (that is, the length W2 of the side 32 and the length W6 of the side 36 are equal), and are parallel and opposed to each other. That is, the three pairs of sides have the same length and are parallel to each other and face each other.

[0034] In this embodiment, the sides 33 and 37 extend in a direction perpendicular to the sides 31 and 35. In this embodiment, the length dimension W1, the length dimension W5, the length dimension W3, and the length dimension W7 are equal to one another. In addition, in this embodiment, the length dimension W2, which is the length of side 32, the length dimension W4, which is the length of side 34, the length dimension W6, which is the length of side 36, and the length dimension W8, which is the length of side 38, are all equal to each other. Furthermore, the length of each of the inclined sides (sides 32, 34, 36, 38) is shorter than the other sides (sides 31, 33, 35, 37). The gaps 81a, 82a, and 83a have the same shape and dimensions and are each an isosceles right triangle. The gap 84a is a right triangle, but is not an isosceles triangle. As an example, the length dimensions W1, W3, W5 and W7 may each be 153 mm, and the length dimensions W2, W4, W6 and W8 may each be 80 mm.

[0035] Therefore, the planar shape of the side periphery 50 of the assembled cardboard box 100 includes a pair of opposing long sides (e.g., sides 31 and 35) and a pair of opposing short sides (sides 32 and 36), and satisfies at least one of the first condition that "the pair of long sides are equal in length and face each other parallel to each other" and the second condition that "the pair of short sides are equal in length and face each other parallel to each other." The long sides are longer than the short sides. In this embodiment, sides 32 and 36, which are inclined sides, are the short sides. In the present embodiment, both the first and second conditions are met. Therefore, it is possible to provide a cardboard box 100 that can be placed in a space that is rectangular in plan view while reducing dead space. In the present invention, the planar shape of the side periphery 50 of the assembled cardboard box 100 may satisfy only one of the first condition (the pair of long sides are equal in length and face each other parallel to each other) and the second condition (the pair of short sides are equal in length and face each other parallel to each other). Here, the lengths of a pair of long sides being equal to each other means that the difference in the lengths of the pair of long sides is preferably ±1.3% or less, more preferably ±1.0% or less, even more preferably ±0.7% or less, and even more preferably ±0.5% or less. Similarly, when the lengths of a pair of short sides are equal to each other, the difference in the lengths of the pair of short sides is preferably ±1.3% or less, more preferably ±1.0% or less, even more preferably ±0.7% or less, and even more preferably ±0.5% or less. In this embodiment, the side 38 and the side 34 are not parallel to each other.

[0036] In this embodiment, the combination of sides (sides 11 to 18) that respectively constitute face 51 and face 52 when folded in two is not limited to the combination shown in Figure 6 (face 51 is constituted by side 12, side 11, side 18 and side 17, and face 52 is constituted by side 13, 14, side 15 and side 16), and any four consecutive sides can be selected.

[0037] Furthermore, the blank sheet 200 of this embodiment is a blank sheet for a cardboard box, and includes a first surface (side surface 11) adjacent to the first intended joining portion 19a with a first score line (score line L1) therebetween, a second surface (side surface 17) adjacent to the second intended joining portion 19b with a second score line (score line L15) therebetween, a third surface (side surface 15) opposite the first surface in the assembled state, and a fourth surface (side surface 13) opposite the second surface in the assembled state. In the circumferential direction, the length (length dimension W1) of the first surface (side surface 11) and the length (length dimension W5) of the third surface (side surface 15) are equal to each other, and the length (length dimension W7) of the second surface (side surface 17) and the length (length dimension W3) of the fourth surface (side surface 13) are equal to each other. By adopting such a configuration, it is possible to ensure good symmetry in the shape when viewed from above. Here, the fact that the length of the first surface and the length of the third surface are equal to each other in the circumferential direction means that the difference in length between the first surface and the third surface is preferably ±1.3% or less, more preferably ±1.0% or less, even more preferably ±0.7% or less, and even more preferably ±0.5% or less. Furthermore, when the length of the second surface and the length of the fourth surface are equal to each other in the circumferential direction, the difference in length between the second surface and the fourth surface is preferably ±1.3% or less, more preferably ±1.0% or less, even more preferably ±0.7% or less, and even more preferably ±0.5% or less.

[0038] In this embodiment, the angles of the base portions of each flap 21, 23, 25, 26, 27, and 28 (angles θ21, θ22, θ23, θ24, θ25, θ26, θ27, θ28, θ29, θ30, θ31, and θ32 shown in Figure 5) are equal to each other, for example, 135° each. As shown in FIG. 2, the first end surface 91 of the joint portion 19 is slightly exposed from the flap 21 in plan view.

[0039] In the assembled state, the blank sheet 200 according to this embodiment has a first surface (side surface 11) and a third surface (side surface 15) that face each other in parallel, and a second surface (side surface 17) and a fourth surface (side surface 13) that face each other in parallel. By adopting such a configuration, it is possible to ensure even better symmetry in the shape as viewed from above.

[0040] In the assembled state, the direction in which the flaps 21, 23 (inner flaps) extend from the side peripheral portion 50 and the direction in which the flaps 22, 24 (outer flaps) extend from the side peripheral portion 50 are perpendicular to each other. Therefore, when the flaps 21, 23, 22, and 24 are folded to form the top surface portion 60, interference between the flaps can be suppressed, and assembly defects can be reduced (assembly can be improved). Furthermore, the tips 21c and 23c of the flaps 21 and 23 (inner flaps) are close to each other and extend parallel to each other. This makes it possible to prevent dust from entering through the top surface portion 60 even in the assembled state, and also makes the top surface portion 60 aesthetically pleasing.

[0041] The blank sheet 200, which becomes the corrugated cardboard box 100 when assembled, is a sheet made of corrugated cardboard. The blank sheet 200 has a core, and a front liner (for example, in this embodiment, the surface that will become the outer surface of the corrugated cardboard box 100 when assembled) is adhered to one side of the core in the thickness direction, and a back liner (for example, in this embodiment, the surface that will become the inner surface of the corrugated cardboard box 100 when assembled) is adhered to the other side in the thickness direction. The core is formed in a corrugated shape. The direction along the corrugations of the core is referred to as the "corrugation direction (grain direction)," and the direction perpendicular to the corrugation direction is referred to as the "anti-corrugation direction." In Figures 1, 3, and 5, a portion of the skin (front liner or back liner) of the blank sheet 200 is not shown to show the corrugations 201 of the core and the corrugation direction. The corrugation direction is the direction that is vertical when assembled. The blank sheet 200 may be subjected to a surface treatment such as a heat-resistant coating or a weather-resistant coating. The material of the blank sheet 200 is not limited to paper, but may be a resin material such as plastic. Furthermore, when a known cardboard sheet is used as the blank sheet 200, there are no particular limitations on its thickness, and cardboard sheets of various known specifications can be appropriately selected. The thickness of the blank sheet 200 may be, for example, 3 mm or more and 5 mm or less, and specific examples thereof include 3 mm, 4 mm, and 5 mm.

[0042] Next, a cardboard box and its blank sheet 250 according to a comparative embodiment will be described with reference to FIGS. The cardboard box and its blank sheet 250 of the comparative embodiment differ from the cardboard box 100 and blank sheet 200 of the present embodiment in the respects described below, but are otherwise configured in the same way as the cardboard box 100 of the present embodiment. The cardboard box and its blank sheet 250 according to the comparative embodiment are similar to the technology disclosed in Patent Document 1.

[0043] As shown in Figure 14, in the cardboard box of the comparative embodiment, when the top and bottom surfaces are open and the side peripheral portion 150 is folded in two, the circumferential length dimensions of the two opposing surfaces (surfaces 151, 152) are different from each other. 14, surfaces 151 and 152 are spaced apart, making it impossible to fold the cardboard box neatly. This results in a cardboard box that is bulky when folded (its thickness increases), and this bulkiness becomes particularly noticeable when multiple cardboard boxes are stacked on top of each other.

[0044] The reason for this is that, among the length dimensions W1 to W7 shown in Fig. 15, the length dimension W1 is set to be longer than that of this embodiment (160 mm, as an example). The reason for setting the dimensions in this manner is to set the angle of each inclined side to the same angle in the planar view shape in the assembled state. That is, in the comparative example, the angle θ11 and the angle θ12 shown in FIG. 16 are equal to each other. However, due to the thickness of the blank sheet, in order to set the angle θ11 and the angle θ12 equal to each other, the length dimension W1 of the cardboard box needs to be longer (than the length dimension W5). For this reason, the cardboard box according to the comparative example cannot be folded neatly, as shown in FIG.

[0045] In contrast to this, in this embodiment, instead of sacrificing the uniformity of the angles θ11 and θ12, the length dimension W1 and the length dimension W5 are made equal to each other, and as a result, the circumferential length dimension of the surface 51 (the sum of the length dimensions W2, W1, W8, and W7 shown in FIG. 4) and the circumferential length dimension of the surface 51 (the sum of the length dimensions W3, W4, W5, W6, and W7 shown in FIG. 4) are made equal to each other. This allows the cardboard box 100 to be neatly folded as shown in Fig. 6. More specifically, second intended joining portion 19b, which is the portion that constitutes the inside of joint portion 19, and side surface 17, which is the portion that has been connected to the portion that constitutes the inside of joint portion 19 since the time of blank sheet 200 and is adjacent to said portion, are close to, and preferably come into surface contact with, side surfaces 15 and 16, which are the portions that face them.

[0046] Second Embodiment Next, a second embodiment will be described with reference to FIGS. The cardboard box 100 and blank sheet 200 of this embodiment differ from the cardboard box 100 and blank sheet 200 of the first embodiment described above in the points described below, but are otherwise configured in the same way as the cardboard box 100 and blank sheet 200 of the first embodiment described above.

[0047] In this embodiment, the angles θ21 and θ25 shown in Fig. 8 are wider than those in the first embodiment. Specifically, for example, the angles θ21 and θ25 are each 139°. As a result, the areas of the flaps 21 and 25 are wider than those in the first embodiment. 7, in the assembled state, the flap 21 covers the entire first end face 91 (upper first end face 91), which is the end face of the joint portion 19 (side face 18). Note that the flap 21 covers the entire second end face 92 (upper first end face 91), which is the end face of the side face 12, as in the first embodiment. Furthermore, in the assembled state, the flap 25 covers the entire first end face 91 (lower first end face 91), which is the end face of the joint portion 19 (side face 18). Note that the flap 25 covers the entire second end face 92 (lower second end face 92), which is the end face of the side face 12, as in the first embodiment.

[0048] Thus, in this embodiment, the blank sheet 200 has a flap 21 connected to the first surface (side surface 11) with the third line (line L2) sandwiched therebetween, and in the assembled state, the flap 21 covers the first end surface 91, which is the end surface of the joint portion 19, and the second end surface 92, which is the end surface of the surface (side surface 12) adjacent to the first surface (side surface 11) in the side peripheral portion component 10 with the fourth line (line L3) sandwiched therebetween. When the first surface (side surface 11) and the flap 21 are laid out flat, the magnitude of the first angle (angle θ21), which is the angle between the first inclined edge 21a of the flap 21 extending from one end (top end) of the first score line (score line L1) and the third score line (score line L2), is greater than the magnitude of the second angle (angle θ22), which is the angle between the second inclined edge 21b of the flap 21 extending from one end (top end) of the fourth score line (score line L3) and the third score line (score line L2), so that in the assembled state, the flap 21 covers the entire first end surface 91 and the entire second end surface 92. Here, the magnitude of the first angle being larger than the magnitude of the second angle means that the first angle is 1° or more larger than the second angle, preferably 2° or more larger than the second angle, and more preferably 3° or more larger than the second angle. In this embodiment, the first angle is approximately 4° larger than the second angle. This makes it possible to prevent dust from entering through the first end surface 91 and the second end surface 92 (particularly the first end surface 91, which is not covered by a typical cardboard box).

[0049] Similarly, the blank sheet 200 has a flap 25 connected to the first surface (side surface 11) with the third score line (score line L4) sandwiched therebetween, and in the assembled state, the flap 25 covers the first end surface 91, which is the end surface of the joint portion 19, and the second end surface 92, which is the end surface of the surface (side surface 12) adjacent to the first surface (side surface 11) in the side peripheral portion component 10 with the fourth score line (score line L3) sandwiched therebetween. When the first surface (side surface 11) and flap 25 are laid out flat, the magnitude of the first angle (angle θ25), which is the angle between the first inclined edge of flap 25 extending from one end (bottom end) of the first score line (score line L1) and the third score line (score line L4), is greater than the magnitude of the second angle (angle θ26), which is the angle between the second inclined edge of flap 25 extending from one end (bottom end) of the fourth score line (score line L3) and the third score line (score line L4), so that in the assembled state, flap 25 covers the entire first end surface 91 and the entire second end surface 92. Here, the magnitude of the first angle being larger than the magnitude of the second angle means that the first angle is 1° or more larger than the second angle, preferably 2° or more larger than the second angle, and more preferably 3° or more larger than the second angle. In this embodiment, the first angle is approximately 4° larger than the second angle. This makes it possible to prevent dust from entering through the first end surface 91 and the second end surface 92 (particularly the first end surface 91, which is not covered by a typical cardboard box).

[0050] In this embodiment, in the cardboard box 100 assembled using the blank sheet 200, the flaps 21 and 25 cover the entire first end surface 91 and the entire second end surface 92.

[0051] According to this embodiment, the flaps 21, 25 cover the entire first end face 91 and the entire second end face 92, thereby preventing dust from entering the first end face 91 or the second end face 92 (especially the first end face 91, which was partially exposed in the first embodiment).

[0052] <Modification> The cardboard box and blank sheet according to the present invention may have a structure different from that of the above-described embodiments, as long as the cardboard box can be folded neatly. Next, the cardboard boxes and blank sheets according to Modifications 1 to 5 will be described with reference to FIGS. 9 to 13, respectively. The cardboard box and blank sheet of each modified example differ from the cardboard box 100 and blank sheet 200 of the first or second embodiment described above in the respects described below, but are otherwise configured in the same way as the cardboard box 100 and blank sheet 200 of the first or second embodiment described above.

[0053] <Variation 1> First, the first modification will be described with reference to FIG. As shown in FIG. 9, the shape of the side peripheral portion 50 in an assembled state in plan view may be an irregular octagon. In this case too, when the top and bottom surfaces of the cardboard box are open and the side periphery 50 is folded in two, the circumferential length dimensions of the two opposing surfaces are equal, allowing the box to be folded neatly. That is, for example, the sum of the length dimensions W7, W8, W1 and W2 is equal to the sum of the length dimensions W3, W4, W5 and W6, so that the folding can be neatly performed. However, the opposing sides do not have to be parallel to each other, and may have different lengths. This modified example does not satisfy the condition that "the shape of side periphery 50 in a plan view when the cardboard box is assembled is a polygon inscribed in an imaginary rectangle 80, with each pair of opposing sides in contact with rectangle 80 over their entire length, and with gaps 81a, 82a, 83a, 84a between four corners 81, 82, 83, 84 of rectangle 80 and the shape in the plan view forming triangles," because gaps 81a and 82a do not form triangles. As described above, the angle θ11 and the angle θ12 are different from each other.

[0054] <Variation 2> Next, Modification 2 will be described with reference to FIG. In this modified example, the gaps 81a, 82a, and 83a have the same shape and dimensions, but are not in the shape of an isosceles right triangle. As in the above, the angle θ11 and the angle θ12 are different from each other. In this modified example, when the top and bottom surfaces of the cardboard box are open and the side periphery 50 is folded in two, the circumferential length dimensions of the two opposing sides are equal, allowing the box to be folded neatly.

[0055] In Modification 2, side 32 and side 36 are parallel to each other, but the present invention is not limited to this example, and side 32 and side 36 do not have to be parallel to each other. In this case, side 31 and side 35 will no longer be parallel to each other, and side 33 and side 37 will no longer be parallel to each other, and the condition that "the shape of side periphery 50 in a planar view when the cardboard box is assembled is a polygon inscribed in an imaginary rectangle 80, with each pair of opposing sides in contact with rectangle 80 over its entire length, and with gaps 81a, 82a, 83a, 84a between the four corners 81, 82, 83, 84 of rectangle 80 and the above-mentioned shape in a planar view forming triangles" will no longer be satisfied.

[0056] <Variation 3> Next, Modification 3 will be described with reference to FIG. In this modified example, the shape of the side periphery 50 in a plan view when the cardboard box is assembled is a substantially regular octagon, and the lengths of the inclined side and the other sides are equal to each other. As in the above, the angle θ11 and the angle θ12 are different from each other. In this modified example, when the top and bottom surfaces of the cardboard box are open and the side periphery 50 is folded in two, the circumferential length dimensions of the two opposing sides are equal, allowing the box to be folded neatly.

[0057] <Variation 4> Next, Modification 4 will be described with reference to FIG. In each of the above embodiments, examples have been described in which the length dimensions (length dimensions W1, W3, W5, W7) of the sides (side surfaces 11, 13, 15, 17) excluding the inclined sides are equal to one another. In contrast, in this modified example, side surfaces 11 and 15 have longer long sides than side surfaces 13 and 17 (side surfaces 13 and 17 have shorter short sides than side surfaces 11 and 15). The rest of the configuration is the same as the first or second embodiment, including the point that the angle θ11 and the angle θ12 are different from each other. In this modified example, when the top and bottom surfaces of the cardboard box are open and the side periphery 50 is folded in two, the circumferential length dimensions of the two opposing sides are equal, allowing the box to be folded neatly.

[0058] <Variation 5> Next, Modification 5 will be described with reference to FIG. In the case of this modified example, the planar shape of side periphery 50 when the cardboard box is assembled is a hexagon, but it satisfies the condition that "the planar shape of side periphery 50 when the cardboard box is assembled is a polygon that is inscribed in an imaginary rectangle 80, with each pair of opposing sides in contact with rectangle 80 over their entire length, and with the gaps 81a, 82a, 83a, 84a between the four corners 81, 82, 83, 84 of rectangle 80 and the above planar shape forming triangles." More specifically, in the plan view shape, the opposing sides 31 and 34 are in contact with the rectangle 80 along their entire length, and these sides 31 and 34 are equal in length and face each other parallel to each other. In this modified example, the planar shape of side periphery 50 when the cardboard box is assembled includes a pair of opposing long sides (sides 31 and 34) and a pair of opposing short sides (e.g., sides 32 and 35), and satisfies at least one of the first condition that the pair of long sides have the same length and are parallel and opposed to each other, and the second condition that the pair of short sides have the same length and are parallel and opposed to each other. More specifically, both the first and second conditions are satisfied. Furthermore, of the four inclined sides (sides 32, 33, 35, and 36), at least one pair of inclined sides located diagonally opposite each other (diagonally opposite corners of rectangle 80) have the same length. More specifically, the length of side 32 and the length of side 35 are equal, and the length of side 33 and the length of side 36 are equal. Even more specifically, the lengths of the four inclined sides are equal. The lengths (length dimensions W2, W3, W5, W6) of the inclined sides (sides 32, 33, 35, 36) can be set according to the dimensions of the contents, so are not particularly limited, but can be, for example, 40 mm or more and 80 mm or less. As in the above, the angle θ11 and the angle θ12 are different from each other. In this modified example, when the top and bottom surfaces of the cardboard box are open and the side periphery 50 is folded in two, the circumferential length dimensions of the two opposing sides are equal, allowing the box to be folded neatly. In this embodiment, the "state when folded in two" means that the side periphery 50 is folded at two locations, namely, the line located at the boundary between side 12 and side 13, and the line located at the boundary between side 15 and side 16, and the side periphery 50 is stretched without being folded at other locations, so that the two portions of the side periphery 50 located between the above two lines (the two opposing surfaces when the side periphery 50 is folded in two) are close to or abutting each other.

[0059] In the case of variant example 5, the blank sheet for the cardboard box also has a side periphery component that forms the side periphery when the cardboard box is assembled, and the side periphery component includes a first intended joining portion 19a and a second intended joining portion 19b that are surface-joined to each other to form a joint portion 19, a first surface (side surface 11) adjacent to the first intended joining portion 19a with the first score line in between, a second surface (side surface 15) adjacent to the second intended joining portion 19b with the second score line in between, a third surface (side surface 14) that faces the first surface (side surface 11) in the assembled state, and a fourth surface (side surface 12) that faces the second surface (side surface 15) in the assembled state. In the circumferential direction, the length (length dimension W1) of the first surface (side surface 11) and the length (length dimension W4) of the third surface (side surface 14) are equal to each other, and the length (length dimension W5) of the second surface (side surface 15) and the length (length dimension W2) of the fourth surface (side surface 12) are equal to each other. Furthermore, in the assembled state, the first surface (side surface 11) and the third surface (side surface 14) face each other in parallel, and the second surface (side surface 15) and the fourth surface (side surface 12) face each other in parallel.

[0060] Although the embodiments and modifications have been described above with reference to the drawings, these are merely examples of the present invention, and various configurations other than those described above can also be adopted.

[0061] For example, the cardboard box and blank sheet may differ from the first embodiment, the second embodiment or variant example 4 in that "none of the opposing inclined sides are parallel to each other." Furthermore, compared to the first or second embodiment, the cardboard box and blank sheet may differ in that, among the long sides (sides 31, 33, 35, 37 excluding the inclined sides), a pair of opposing sides (for example, sides 31, 35) are parallel to each other, while another pair of opposing sides (for example, sides 33, 37) are not parallel to each other. Alternatively, the cardboard box and blank sheet may differ from those of Modification 4 in that the long sides (sides 31, 35) are parallel to each other but the short sides (sides 33, 37) are not parallel to each other. Alternatively, the cardboard box and blank sheet may differ from those of Modification 4 in that the short sides (sides 33, 37) are parallel to each other but the long sides (sides 31, 35) are not parallel to each other. Furthermore, when the planar shape of side periphery 50 when the cardboard box is assembled is a hexagon as in variant 5, as explained in variant 1, it does not have to satisfy the condition that "the planar shape of side periphery 50 when the cardboard box is assembled is a polygon inscribed in an imaginary rectangle 80, with each pair of opposing sides in contact with rectangle 80 over its entire length, and with the gaps 81a, 82a, 83a, 84a between the four corners 81, 82, 83, 84 of rectangle 80 and the above planar shape forming triangles," and the opposing sides do not have to be parallel to each other or may be of different lengths.

[0062] The present embodiment encompasses the following technical ideas. (1) A corrugated cardboard box in which the joints are surface-bonded and the side periphery is a continuous loop, The planar shape of the side periphery of the assembled cardboard box is a polygon inscribed in an imaginary rectangle, with each pair of opposing sides contacting the rectangle over their entire length, and with the gaps between the four corners of the rectangle and the planar shape forming triangles, A cardboard box in which the circumferential length dimensions of the two opposing faces are equal when the top and bottom surfaces of the cardboard box are open and the side periphery is folded in two. (2) The planar view shape includes a first side that is one of the pair of sides, a second side that is adjacent to the first side and includes the joint portion, and a third side that is adjacent to the first side on the opposite side to the second side, The cardboard box according to (1), wherein the angle formed between the first side and the second side and the angle formed between the first side and the third side are different from each other. (3) The planar shape is an octagon including four inclined sides facing the four corners of the rectangle, The cardboard box according to (1) or (2), wherein at least one pair of diagonally opposite inclined sides of the four inclined sides have the same length. (4) The cardboard box according to (3), wherein the length of the inclined side is 40 mm or more and 80 mm or less. (5) A corrugated cardboard box in which the joints are surface-bonded and the side periphery is a continuous loop, The planar shape of the side periphery of the cardboard box in an assembled state is octagonal or hexagonal, A cardboard box in which the circumferential length dimensions of the two opposing faces are equal when the top and bottom surfaces of the cardboard box are open and the side periphery is folded in two. (6) The planar view shape includes a pair of sides facing each other, a second side adjacent to a first side that is one of the pair of sides and that includes the joint portion, and a third side adjacent to the first side on the opposite side to the second side, The cardboard box according to (5), wherein the angle formed between the first side and the second side and the angle formed between the first side and the third side are different from each other. (7) The planar shape includes a pair of opposing sides, The cardboard box according to any one of (1) to (6), wherein the pair of sides are equal in length and parallel to each other and face each other. (8) The planar shape of the side periphery of the corrugated cardboard box in an assembled state includes a pair of long sides facing each other and a pair of short sides facing each other, A first condition is that the pair of long sides have equal lengths and are parallel to each other and face each other; A second condition is that the pair of short sides have equal lengths and are parallel to each other and face each other. The cardboard box according to any one of (1) to (6), which satisfies at least one of the above. (9) The cardboard box according to (8) above, which satisfies both the first and second conditions. (10) A plurality of flaps that form a top surface portion in the assembled state, and a plurality of flaps that form a bottom surface portion in the assembled state, A cardboard box according to any one of (1) to (9), in which the assembled state is achieved by joining together a plurality of flaps constituting the top surface portion and joining together a plurality of flaps constituting the bottom surface portion. (11) A blank sheet for a cardboard box, A side periphery forming portion that forms a side periphery of the cardboard box in an assembled state is provided, The side periphery constituent portion is a first intended joining portion and a second intended joining portion that are surface-joined to each other to form a joint portion; A first surface adjacent to the first intended joining portion with a first ruled line interposed therebetween; A second surface adjacent to the second intended joining portion with a second ruled line interposed therebetween; a third surface facing the first surface in the assembled state; a fourth surface facing the second surface in the assembled state; Including, A blank sheet in which the first surface and the third surface have the same length in the circumferential direction, and the second surface and the fourth surface have the same length. (12) The blank sheet according to (11), wherein, in the assembled state, the first surface and the third surface are parallel and opposed to each other, and the second surface and the fourth surface are parallel and opposed to each other. (13) A flap is provided which is connected to the first surface with a third ruled line sandwiched therebetween, the flap covers, in the assembled state, a first end surface that is an end surface of the joint portion and a second end surface that is an end surface of a surface of the side peripheral portion constituent portion that is adjacent to the first surface with a fourth crease interposed therebetween, When the first surface and the flap are flatly unfolded, a first angle formed between a first inclined side of the flap extending from one end of the first crease and the third crease is larger than a second angle formed between a second inclined side of the flap extending from one end of the fourth crease and the third crease, The blank sheet according to (11) or (12), wherein the flap covers the entire first end surface and the entire second end surface in the assembled state. (14) A cardboard box in the assembled state using the blank sheet according to (13), The cardboard box has the flap covering the entire first end surface and the entire second end surface. [Explanation of symbols]

[0063] 10 Side peripheral portion component 11, 12, 13, 14, 15, 16, 17, 18 Sides 19a First planned joining section 19b Second planned joining section 19 Joint 21, 22, 23, 24, 25, 26, 27, 28 Flap 21a 1st slope side 21b 2nd slope side 21c, 23c tip Sides 31, 32, 33, 34, 35, 36, 37, and 38 50 Side circumference 51, 52 Two opposing sides 60 Top section 61 Break Line 70 Bottom part 80 Imaginary Rectangle 81, 82, 83, 84 4 corners 81a, 82a, 83a, 84a gap 91 1st end face 92 Second end face 100 cardboard boxes 200 blank sheets 201st row P1, P2, P3, P4, P5, P6, P7, P8 points L1, L2, L3, L4, L5, L6, L7, L8, L9, L10, L11, L12, L13, L14, L15, L16 ruled lines θ1 1st angle θ2 2nd angle θ11 Angle between the first and second sides θ12 Angle between the first and third sides

Claims

1. A corrugated cardboard box in which the joint portion is surface-bonded and the side periphery is a series of loops, The shape of the side periphery in a plan view of the assembled cardboard box is a polygon inscribed in an imaginary rectangle, with each pair of opposing sides in contact with the rectangle over their entire length, and with the gaps between the four corners of the rectangle and the shape in the plan view forming triangles, When the top and bottom surfaces of the cardboard box are open and the side periphery is folded in two, the circumferential lengths of the two opposing surfaces are equal to each other.

2. the planar view shape includes a first side that is one side of the pair of sides, a second side that is adjacent to the first side and includes the joint portion, and a third side that is adjacent to the first side on the opposite side to the second side, 2. The cardboard box according to claim 1, wherein an angle formed between the first side and the second side is different from an angle formed between the first side and the third side.

3. the shape in plan view is an octagon including four inclined sides facing the four corners of the rectangle, 2. The cardboard box according to claim 1, wherein at least one pair of diagonally opposite inclined sides of the four inclined sides have the same length.

4. 4. The cardboard box according to claim 3, wherein the length of the inclined side is 40 mm or more and 80 mm or less.

5. A corrugated cardboard box in which the joint portion is surface-bonded and the side periphery is a series of loops, The planar shape of the side periphery of the cardboard box in an assembled state is octagonal or hexagonal, When the top and bottom surfaces of the cardboard box are open and the side periphery is folded in two, the circumferential lengths of the two opposing surfaces are equal to each other.

6. the planar view shape includes a pair of sides facing each other, a second side that is adjacent to a first side that is one of the pair of sides and that includes the joint portion, and a third side that is adjacent to the first side on the opposite side to the second side, 6. The cardboard box according to claim 5, wherein an angle formed between the first side and the second side is different from an angle formed between the first side and the third side.

7. the planar view shape includes a pair of sides facing each other, 7. The cardboard box according to claim 1, wherein the pair of sides have the same length and are parallel to each other and face each other.

8. The planar shape of the side periphery of the assembled cardboard box includes a pair of long sides facing each other and a pair of short sides facing each other, A first condition is that the pair of long sides have equal lengths and are parallel to and opposite to each other; A second condition is that the pair of short sides have equal lengths and are parallel to each other and face each other. The cardboard box according to any one of claims 1 to 6, which satisfies at least one of the above.

9. The cardboard box according to claim 8 , which satisfies both the first condition and the second condition.

10. a plurality of flaps that form a top surface portion in the assembled state; and a plurality of flaps that form a bottom surface portion in the assembled state, 7. The cardboard box according to claim 1, wherein the assembled state is achieved by joining together a plurality of flaps constituting the top surface portion and joining together a plurality of flaps constituting the bottom surface portion.

11. A blank sheet for a cardboard box, A side periphery forming portion that forms a side periphery of the cardboard box in an assembled state is provided, The side periphery constituent portion is a first intended joining portion and a second intended joining portion that are surface-joined to each other to form a joint portion; a first surface adjacent to the first intended joining portion across a first ruling line; A second surface adjacent to the second intended joining portion with a second ruling line interposed therebetween; a third surface facing the first surface in the assembled state; a fourth surface facing the second surface in the assembled state; Including, A blank sheet in which the first surface and the third surface have the same length in the circumferential direction, and the second surface and the fourth surface have the same length.

12. The blank sheet according to claim 11 , wherein, in the assembled state, the first surface and the third surface are parallel and opposed to each other, and the second surface and the fourth surface are parallel and opposed to each other.

13. a flap connected to the first surface with a third line sandwiched therebetween; the flap covers, in the assembled state, a first end surface that is an end surface of the joint portion and a second end surface that is an end surface of a surface of the side peripheral portion constituent portion that is adjacent to the first surface with a fourth crease interposed therebetween, When the first surface and the flap are flatly unfolded, a first angle formed between a first inclined side of the flap extending from one end of the first crease and the third crease is larger than a second angle formed between a second inclined side of the flap extending from one end of the fourth crease and the third crease, 13. The blank sheet according to claim 11, wherein the flap covers the entire first end surface and the entire second end surface in the assembled state.

14. A corrugated cardboard box in the assembled state using the blank sheet according to claim 13, The cardboard box has the flap covering the entire first end surface and the entire second end surface.

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