Packing box

Abstract

To provide a packing box capable of satisfactorily maintaining a state where an insertion piece is engaged with an insertion slit after the insertion of the insertion piece into the insertion slit while the insertion piece can be easily inserted into the insertion slit.SOLUTION: A packing box 100 comprises: an inner flap 20 having an insertion slit 40; and an outer flap 50 having an insertion piece 60 inserted into the insertion slit 40. The insertion piece 60 is disposed at a first edge 53, and protrudes from an outer flap body 51 in a direction away from a first oscillation axis AX1. The insertion piece 60 has an insertion body 62 and a protrusion piece 64. The insertion slit 40 has a first slit 44 and a second slit 46. The inner flap 20 has a first guide piece 30. A part of the inner flap 20 that is adjacent to the side of the second slit 46 away from the first oscillation axis AX1 is a pressing part 22.SELECTED DRAWING: Figure 18

Description

[Technical field]

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

[0002] A packaging box having an inner flap having an insertion slit and an outer flap having an insertion piece to be inserted into the insertion slit and arranged overlapping the outer side of the inner flap is described in, for example, Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2000-355321 A Summary of the Invention [Problem to be solved by the invention]

[0004] According to the investigations of the present inventors, there is room for improvement in the packaging box described in Patent Document 1 in terms of ease of inserting the insertion pieces into the insertion slits.

[0005] To provide a packaging box that allows an insertion piece to be easily inserted into an insertion slit, while at the same time allowing the insertion piece to maintain a good engagement with the insertion slit after being inserted into the insertion slit. [Means for solving the problem]

[0006] The present invention provides a packaging box having an inner flap having an insertion slit, and an outer flap having an insertion piece to be inserted into the insertion slit and arranged to overlap the outer side of the inner flap, The insertion slit extends in a direction along a first pivot axis which is a pivot axis of the outer flap, The outer flap has an outer flap body including the first swing shaft, The insertion piece is disposed on a first edge portion of the outer flap that is an edge portion farther from the first swing shaft, and protrudes from the outer flap body in a direction away from the first swing shaft, The insertion piece has an insertion body portion directly connected to the outer flap body, and a protruding piece protruding from the insertion body portion in a direction along the first swing shaft and connected to the outer flap body via the insertion body portion, The insertion slit has a first slit into which the insertion body portion is inserted and a second slit into which the protruding piece is inserted, the inner flap has a first guide piece disposed adjacent to the first slit on the first pivot shaft side, This relates to a packaging box in which the portion of the inner flap adjacent to the second slit on the side farther from the first pivot axis serves as a pressing portion that presses the protruding piece in the thickness direction when the insertion piece is inserted into the insertion slit. Effect of the Invention

[0007] According to the present invention, the insertion piece can be easily inserted into the insertion slit, while after the insertion piece is inserted into the insertion slit, the insertion piece can be well maintained in an engaged state with the insertion slit. [Brief description of the drawings]

[0008] [Figure 1] 1 is a perspective view of a packaging box according to an embodiment, viewed from the top side. [Diagram 2] FIG. 2 is a perspective view of the packaging box according to the embodiment, viewed from the bottom side. [Diagram 3] FIG. 2 is a side view of the packaging box according to the embodiment. [Figure 4] FIG. 2 is a bottom view of the packaging box according to the embodiment. [Diagram 5] FIG. 2 is a development view of a packaging box according to the embodiment. [Figure 6] FIG. 2 is a diagram showing a state in which the packaging box according to the embodiment is folded flat. [Figure 7]1 is a development view of a packaging box according to an embodiment, showing one inner flap and its surrounding structure as viewed from the side that will become the inner surface of the packaging box. FIG. [Figure 8] 1 is a development view of a packaging box according to an embodiment, showing one outer flap and its surrounding structure as viewed from the side that will become the inner surface of the packaging box. FIG. [Figure 9] 1 is a development view of a packaging box according to an embodiment, showing one insertion slit and its surrounding structure as viewed from the side that becomes the inner surface of the packaging box. FIG. [Figure 10] 1 is a development view of a packaging box according to an embodiment, showing one insertion piece and its surrounding structure as viewed from the inner side, which will become the inner surface of the packaging box. FIG. [Figure 11] FIG. 11(a) is a partially enlarged bottom view of the packaging box (as viewed from the outer surface side of the packaging box), and FIG. 11(b) is a partially enlarged bottom view of the packaging box (as viewed from the inner surface side of the packaging box). [Figure 12] Figures 12(a) and 12(b) are figures showing the state before the insertion piece is inserted into the insertion slit in the embodiment, and of these, Figure 12(a) is a view of the insertion slit, the insertion piece and their surrounding structure from the inner side of the packaging box, and Figure 12(b) is a cross-sectional end view taken along line AA shown in Figure 12(a). [Figure 13] Figures 13(a) and 13(b) are figures showing the state in which the tip of the insertion piece is inserted into the insertion slit in the embodiment, and of these, Figure 13(a) is a view of the insertion slit, the insertion piece and their surrounding structure from the inner side of the packaging box, and Figure 13(b) is a cross-sectional end view taken along line AA shown in Figure 13(a). [Figure 14] Figures 14(a) and 14(b) are figures showing the state in which the middle part of the insertion piece is inserted into the insertion slit in the embodiment, and of these, Figure 14(a) is a view of the insertion slit, the insertion piece and their surrounding structure from the inner side of the packaging box, and Figure 14(b) is a cross-sectional end view taken along line AA shown in Figure 14(a). [Figure 15]Figures 15(a) and 15(b) are figures showing the state in which the insertion piece is inserted to the deepest extent into the insertion slit in an embodiment, and of these, Figure 15(a) is a view of the insertion slit, the insertion piece and their surrounding structure from the inner surface side of the packaging box, and Figure 15(b) is a cross-sectional end view taken along line AA shown in Figure 15(a). [Figure 16] Figures 16(a) and 16(b) are figures showing the state in which the insertion piece is engaged with the insertion slit in an embodiment, where Figure 16(a) is a view of the insertion slit, the insertion piece and their surrounding structure from the inner side of the packaging box, and Figure 16(b) is a cross-sectional end view taken along line AA shown in Figure 16(a). [Figure 17] FIG. 16(b) is a cross-sectional view taken along line BB shown in FIG. [Figure 18] 13 is a view showing the state in which the insertion piece is engaged with the insertion slit, as viewed from the inner surface side of the packaging box. [Figure 19] FIG. 11 is a perspective view showing a state in which a protruding piece is erected in the embodiment, and an inner flap is not shown. [Figure 20] Figure 20(a) is a bottom view (viewed from the outer surface side of the packaging box) showing the pressing piece and its surrounding structure in the embodiment, Figure 20(b) is a cross-sectional end view along line AA shown in Figure 20(a), and Figure 20(c) shows the state in which contents are placed on the bottom portion from the state shown in Figure 20(b). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are designated by the same reference numerals, and duplicated descriptions will be omitted as appropriate. In addition, in the present invention, the description of the positional relationship (upper and lower relationships, etc.) of each component of the packaging box 100 describes the positional relationship when the packaging box 100 is assembled as shown in Figures 1 to 4, unless otherwise specified. In the following description, the inner side of the packaging box 100 (the side of the storage area 19 described later) may be referred to as the inside, and the opposite side of the inner side of the packaging box 100 (same as above) may be referred to as the outside. Similarly, the surface of the inner side (same as above) of the packaging box 100 may be referred to as the inner surface (inner surface side), and the surface opposite the inner surface may be referred to as the outer surface (outer surface side). Moreover, the drawings used in this embodiment are intended to illustrate the configuration and shape of the packaging box 100 of the present invention and the arrangement of each member constituting the packaging box 100, and are not intended to limit the present invention. Moreover, the drawings do not necessarily accurately represent the dimensional ratios of the packaging box 100, such as the length, width, and height. In addition, the terms "orthogonal" and "parallel" in this specification include the range of error permitted in the technical field to which the present invention belongs. For example, unless otherwise specified, "orthogonal" and "parallel" in this specification mean that the deviation is within a range of less than ±10° from strictly orthogonal or parallel. The deviation from strictly orthogonal or strictly parallel is preferably ±5° or less, and more preferably ±3° or less.

[0010] As shown in any one of Figures 1 to 5, the packaging box 100 of this embodiment has an inner flap 20 (e.g., lower inner flaps 20a, 20b described below) having an insertion slit 40, and an outer flap 50 (e.g., lower outer flaps 50a, 50b described below) having an insertion piece 60 to be inserted into the insertion slit 40 and arranged overlapping the outside of the inner flap 20. The insertion slit 40 extends in a direction along a first swing axis AX1 (see Figs. 2, 8, etc.) which is a swing axis of the outer flap 50. The outer flap 50 has an outer flap main body 51 including the first swing axis AX1. The insertion piece 60 is arranged on the first edge 53, which is the edge of the outer flap 50 on the side farther from the first swing axis AX1 (the upper side in Figure 8), and protrudes from the outer flap main body 51 in a direction away from the first swing axis AX1. The insertion piece 60 has an insertion body portion 62 directly connected to the outer flap body 51, and a protruding piece 64 protruding from the insertion body portion 62 in a direction along the first pivot axis AX1 and connected to the outer flap body 51 via the insertion body portion 62. The insertion slit 40 has a first slit 44 into which the insertion main body portion 62 is inserted, and a second slit 46 into which the protruding piece 64 is inserted. As shown in FIG. 7, the inner flap 20 has a first guide piece 30 disposed adjacent to the first slit 44 on the side of the first oscillation axis AX1. In addition, the portion of the inner flap 20 adjacent to the second slit 46 on the side farther from the first swing axis AX1 constitutes a pressing portion 22 which presses the protruding piece 64 in the thickness direction (thickness direction of the pressing portion 22) when the insertion piece 60 is inserted into the insertion slit 40.

[0011] Here, "the insertion slit 40 extends in a direction along the first oscillation axis AX1" means that the extension direction of a virtual line (not shown) linearly connecting one end 42 and the other end 43 (see FIG. 9) of the insertion slit 40 extends in a direction including a component of the direction of the first oscillation axis AX1. In other words, both the first slit 44 and the second slit 46 have a dimension in a direction parallel to the first oscillation axis AX1. Preferably, the inclination angle of the imaginary line with respect to the first oscillation axis AX1 is less than 45°. Moreover, the "direction away from the first oscillation axis AX1 (direction approaching the first oscillation axis AX1)" refers to the direction away from the first oscillation axis AX1 (direction approaching the first oscillation axis AX1) within the range of a flat imaginary plane 310 (described in detail later) having the first oscillation axis AX1 as one side and the second oscillation axis AX2, which is the oscillation axis of the inner flap 20, as the other side. Similarly, the "direction away from the second oscillation axis AX2 (direction approaching the second oscillation axis AX2)" refers to the direction away from the second oscillation axis AX2 (direction approaching the second oscillation axis AX2) within the range of the imaginary plane 310. Furthermore, "the insertion piece 60 protrudes from the outer flap main body 51 in a direction away from the first swing axis AX1" means that the insertion piece 60 protrudes further away from the first swing axis AX1 than the edge of the outer flap main body 51 that is farther from the first swing axis AX1 (in this embodiment, the second edge 512a described later). Moreover, "the protruding piece 64 protrudes in a direction along the first oscillation axis AX1" means that the protruding piece 64 protrudes in a direction parallel to the first oscillation axis AX1 from the insertion body 62. More specifically, in this embodiment, the protruding piece 64 protrudes in a direction along the first oscillation axis AX1, away from the second oscillation axis AX2. The protruding direction of the insertion piece 60 is indicated by an arrow A in FIG. 10, and the protruding direction of the protruding piece 64 is indicated by an arrow B in FIG. In this embodiment, the first swing axis AX1 constitutes the boundary between the body section 10 and the outer flap 50, which will be described later. Therefore, the body section 10 and the outer flap 50 share the first swing axis AX1. Therefore, the outer flap 50 includes the first swing axis AX1.

[0012] In this embodiment, as described later, the inner flap 20 has a plurality of insertion slits 40 (lower insertion slits 40a to 40d). The packaging box 100 has a plurality of outer flaps 50 (lower outer flaps 50a, 50b). Insertion pieces 60 (lower insertion pieces 60a to 60d) of the outer flaps 50 are inserted into and engaged with the plurality of insertion slits 40 of the common inner flap 20. In this case, the inner flap 20 has an insertion slit 40 (referred to as the first insertion slit) into which the insertion piece 60 (referred to as the first insertion piece) of one outer flap 50 (referred to as the first outer flap) among the multiple outer flaps 50 is inserted, and an insertion slit 40 (referred to as the second insertion slit) into which the insertion piece 60 (referred to as the second insertion piece) of another outer flap 50 (referred to as the second outer flap) among the multiple outer flaps 50 is inserted.

[0013] Among these, the first swing axis AX1 side (and the side farther from the first swing axis AX1) of the first insertion slit refers to the first swing axis AX1 side (and the side farther from the first swing axis AX1) of the first outer flap having the first insertion piece inserted into the first insertion slit. Also, the second swing axis AX2 side (and the side farther from the second swing axis AX2) of the first insertion slit refers to the second swing axis AX2 side (and the side farther from the second swing axis AX2) of the first inner flap having the first insertion slit. Similarly, with respect to the second insertion slit, the first swing axis AX1 side (and the side farther from the first swing axis AX1) refers to the first swing axis AX1 side (and the side farther from the first swing axis AX1) of the second outer flap having the second insertion piece inserted into the second insertion slit. Also, with respect to the second insertion slit, the second swing axis AX2 side (and the side farther from the second swing axis AX2) refers to the second swing axis AX2 side (and the side farther from the second swing axis AX2) of the second inner flap having the second insertion slit. Moreover, with respect to the first insertion piece, the first swing axis AX1 side (and the side farther from the first swing axis AX1) is the first swing axis AX1 side (and the side farther from the first swing axis AX1) of the first outer flap having the first insertion piece. Moreover, with respect to the first insertion piece, the second swing axis AX2 side (and the side farther from the second swing axis AX2) is the second swing axis AX2 side (and the side farther from the second swing axis AX2) of the first inner flap having a first insertion slit into which the first insertion piece is inserted. Similarly, with respect to the second insertion piece, the first swing axis AX1 side (and the side farther from the first swing axis AX1) refers to the first swing axis AX1 side (and the side farther from the first swing axis AX1) of the second outer flap having the second insertion piece. Also, with respect to the second insertion piece, the second swing axis AX2 side (and the side farther from the second swing axis AX2) refers to the second swing axis AX2 side (and the side farther from the second swing axis AX2) of the second inner flap having a second insertion slit into which the second insertion piece is inserted.

[0014] In the packaging box 100, the inner flap 20 and the outer flap 50 are engaged with each other by an insertion operation (hereinafter, may be simply referred to as an insertion operation) of inserting the insertion piece 60 into the insertion slit 40. During the insertion operation, the insertion piece 60 is inserted into the insertion slit 40 while moving in a direction away from the first oscillation axis AX1. That is, the insertion direction of the insertion piece 60 (hereinafter, may be simply referred to as the insertion direction) is the direction in which the insertion piece 60 moves relative to the insertion slit 40 during the insertion operation, and includes a component of the direction away from the first oscillation axis AX1. In the following description, the near side in the insertion direction is the side of the first oscillation axis AX1 in the imaginary plane 310, and the far side in the insertion direction is the side in the imaginary plane 310 farther from the first oscillation axis AX1. Moreover, from a state in which the insertion piece 60 is inserted into the insertion slit 40, the insertion piece 60 can be pulled out from the insertion slit 40 by moving the insertion piece 60 in a direction approaching the first oscillation axis AX1. That is, the pulling direction of the insertion piece 60 (hereinafter, may be simply referred to as the pulling direction) includes a component of a direction approaching the first oscillation axis AX1.

[0015] 7 and 8, according to this embodiment, the inner flap 20 has the first guide piece 30 disposed adjacent to the first slit 44 on the first swing axis AX1 side (the front side in the insertion direction). Therefore, when the insertion piece 60 is inserted into the insertion slit 40, the insertion piece 60 is guided toward the first slit 44 while abutting against the first guide piece 30 (while pressing the first guide piece 30 inward). Therefore, the insertion piece 60 can be smoothly inserted into the insertion slit 40. In addition, the protruding piece 64 connected to the outer flap body 51 via the insertion body 62 is a portion that is easily bent with respect to the insertion body 62, so that by inserting the insertion piece 60 into the insertion slit 40, the protruding piece 64 is pushed by the pressing portion 22 of the inner flap 20 and stands up inward (see FIG. 18, etc.). Then, the standing protruding piece 64 engages with a portion (in the case of this embodiment, the second guide piece 36 described later) adjacent to the first swing axis AX1 side with respect to the second slit 46 in the inner flap 20. Therefore, even if the insertion piece 60 is unintentionally pulled in the pull-out direction, the insertion piece 60 including the protruding piece 64 can be prevented from coming out of the insertion slit 40. Therefore, the state in which the insertion piece 60 is engaged (locked) with the insertion slit 40 can be well maintained without using a staple or the like. Furthermore, since the insertion slit 40 has the second slit 46 corresponding to the protruding piece 64 , the insertion piece 60 including the standing protruding piece 64 can be easily inserted into the insertion slit 40 . Thus, according to this embodiment, the insertion piece 60 can be easily inserted into the insertion slit 40, while after the insertion piece 60 is inserted into the insertion slit 40, the insertion piece 60 can maintain a good engagement with the insertion slit 40. Here, "the protruding piece 64 stands up" means that the protruding piece 64 is inclined at least inward with respect to the insertion body 62. In the state in which the protruding piece 64 stands up, the surface direction of the protruding piece 64 intersects with the surface direction of the insertion body 62 and also intersects with the surface direction of the imaginary plane 310 described above. More specifically, as shown in Figure 18, in this embodiment, the protruding piece 64 stands inward relative to the insertion main body portion 62, and the surface direction of the standing protruding piece 64 intersects with the surface direction of the second guide piece 36 described later.

[0016] The packaging box 100 will be described in more detail below. In the following, when describing the positional relationship of each component of the packaging box 100, the front side of the packaging box 100 (the left side of the paper in FIG. 3) will be referred to as the front, the back side of the packaging box 100 (the right side of the paper in FIG. 3) as the rear, the left side as viewed from the front of the packaging box 100 (the back side of the paper in FIG. 3) as the left side, and the right side as viewed from the front of the packaging box 100 (the front side of the paper in FIG. 3) as the right side. The left-right direction of the packaging box 100 may also be referred to as the width direction. However, these directions are specified for convenience only, and do not limit the directions of the packaging box 100 during manufacture or use. As described above, the positional relationships (upper and lower relationships, etc.) of the components of the packaging box 100 are described with reference to the state in which the packaging box 100 is assembled as shown in Figures 1 to 4 unless otherwise specified. However, the positional relationships in these descriptions do not necessarily match the positional relationships before and during the assembly of the packaging box 100. In addition, unless otherwise specified, the description of the positional relationship of each component of the outer flap 50 describes the positional relationship with respect to the first oscillation axis AX1 when the outer flap 50 is in a flat state (unbent state) as shown in Figure 8. In addition, unless otherwise specified, the description of the positional relationship of the components of the inner flap 20 describes the positional relationship with respect to the first oscillation axis AX1 when the inner flap 20 is in a flat state (unbent state) as shown in Figure 7 and when the inner flap 20 is positioned along the imaginary plane 310.

[0017] As shown in Figs. 1 to 4, in this embodiment, the packaging box 100 has a schematic shape of a flattened (shallow vertical dimension) rectangular parallelepiped. More specifically, the packaging box 100 has, for example, a body portion 10 formed in a rectangular ring shape in a plan view, a top surface portion 16 disposed on the upper side of the body portion 10, and a bottom surface portion 18 disposed on the lower side of the body portion 10. The area surrounded by the body portion 10, the top surface portion 16, and the bottom surface portion 18 is the storage area 19 of the packaging box 100 (see Fig. 1, etc.). As shown in Fig. 20(c), the contents 400 are disposed on the inner surface (upper surface) of the bottom surface portion 18. In Fig. 20(c), the contents 400 are indicated by a two-dot chain line. However, in the present invention, the shape of the packaging box 100 is not limited to this example, and the packaging box 100 may not have, for example, the top surface portion 16. In addition, the shape of the packaging box 100 is not limited to a rectangular parallelepiped shape (hexahedral shape), and may be any shape having at least one or more planar portions.

[0018] The body portion 10 is formed in a rectangular ring shape in a plan view, including a front portion 11, a left side portion 13, a right side portion 14, and a back portion 15. The front surface portion 11 and the rear surface portion 15 face each other in parallel, and the left side surface portion 13 and the right side surface portion 14 face each other in parallel. Each of the front surface portion 11, the left side surface portion 13, the right side surface portion 14, and the rear surface portion 15 is formed, for example, in the shape of a rectangular flat plate. The front surface 11 and the rear surface 15 are formed to have the same dimensions and shape. The left side surface 13 and the right side surface 14 are formed to have the same dimensions and shape.

[0019] The bottom portion 18 is an openable / closable lid that can close the lower end opening of the body portion 10 . More specifically, the bottom portion 18 has a lower inner flap 20a connected to the lower edge of the left side portion 13, a lower inner flap 20b connected to the lower edge of the right side portion 14, a lower outer flap 50a connected to the lower edge of the front portion 11, and a lower outer flap 50b connected to the lower edge of the back portion 15. A pair of lower insertion slits 40a to 40d (see FIG. 2) are formed on the lower inner flaps 20a and 20b, respectively. Also, a pair of lower insertion pieces 60a to 60d (see FIG. 2) are formed on the lower outer flaps 50a and 50b, respectively. Then, the lower insertion piece 60a is inserted into the lower insertion slit 40a so that the left part of the lower outer flap 50a (one side part in the longitudinal direction of the lower outer flap 50a) is overlapped from the outside onto the front part of the lower inner flap 20a (one side part in the longitudinal direction of the lower inner flap 20a). Similarly, the lower insertion piece 60b is inserted into the lower insertion slit 40b so that the right part of the lower outer flap 50a (the other side part in the longitudinal direction of the lower outer flap 50a) is overlapped from the outside onto the front part of the lower inner flap 20b (one side part in the longitudinal direction of the lower inner flap 20b). Also, the lower insertion piece 60c is inserted into the lower insertion slit 40c so that the left part of the lower outer flap 50b (one side part in the longitudinal direction of the lower outer flap 50a) is overlapped from the outside onto the rear part of the lower inner flap 20a (the other side part in the longitudinal direction of the lower inner flap 20a). Similarly, the lower insertion piece 60d is inserted into the lower insertion slit 40d so that the right part of the lower outer flap 50b (the other side part in the longitudinal direction of the lower outer flap 50a) is overlapped from the outside onto the rear part of the lower inner flap 20b (the other side part in the longitudinal direction of the lower inner flap 20b). As a result, the left portions (same as above) of the lower outer flaps 50a, 50b engage with the lower inner flap 20a, and the right portions (same as above) of the lower outer flaps 50a, 50b engage with the lower inner flap 20b. In this way, the bottom portion 18, which is an opening / closing lid, is in a closed state (see FIG. 2), and the lower end opening of the body portion 10 is closed.

[0020] The top surface portion 16 is an openable / closable lid that can close the upper end opening of the body portion 10 . More specifically, the top surface portion 16 has an upper inner flap 20c connected to the upper edge of the left side surface portion 13, an upper inner flap 20d connected to the upper edge of the right side surface portion 14, an upper outer flap 50c connected to the upper edge of the front surface portion 11, and an upper outer flap 50d connected to the upper edge of the back surface portion 15. A pair of upper insertion slits 40e-40h (see FIG. 1) are formed in the upper inner flaps 20c, 20d, respectively. Also, a pair of upper insertion pieces 60e-60h (see FIG. 1) are formed in the upper outer flaps 50c, 50d, respectively. Then, similarly to the bottom surface portion 18, by inserting the corresponding upper insertion pieces 60e-60h into the upper insertion slits 40e-40h, the left end portions of the upper outer flaps 50c, 50d engage with the upper inner flap 20c, and the right end portions of the upper outer flaps 50c, 50d engage with the upper inner flap 20d. In this manner, the top surface portion 16, which is an opening / closing lid, is in a closed state (see FIG. 1), and the upper end opening of the body portion 10 is closed.

[0021] The packaging box 100 is formed, for example, by folding and assembling a blank sheet 200 (packaging box constituent sheet) shown in FIG. 5 and the like. The packaging box 100 is, for example, a cardboard box, and the blank sheet 200 is a sheet made of cardboard. The blank sheet 200 has a core, and a front liner (for example, the surface that becomes the outer surface of the packaging box 100 in the case of this embodiment) is attached to one side in the thickness direction of the core, and a back liner (for example, the surface that becomes the inner surface of the packaging box 100 in the case of this embodiment) is attached to the other side in the thickness direction. The core is a plate-like member formed in a corrugated shape. In the following description, in Figs. 5 to 10, the direction along the corrugations of the core indicated by the arrow X 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". Also, in Figs. 5, 6, 7, and 8, the corrugations 280 and the corrugation direction of the core are shown with a part of the skin (front liner or back liner) of the blank sheet 200 not shown. However, in the present invention, the material of the packaging box 100 (blank sheet 200) is not particularly limited. More specifically, the material of the blank sheet 200 can be appropriately selected from known paper materials such as cardboard, in addition to a cardboard sheet, depending on the specifications of the packaging box 100. Furthermore, the blank sheet 200 may be subjected to a surface treatment such as a heat-resistant and weather-resistant coating. Furthermore, the material of the blank sheet 200 is not limited to the above-mentioned paper materials, and may be, for example, a resin material such as plastic. Furthermore, when a known cardboard sheet is used as the blank sheet 200, its thickness is not particularly limited, and known cardboard sheets of various specifications can be appropriately selected. In the present invention, the packaging box 100 (blank sheet 200) may be made of a material that does not have the above-mentioned core, i.e., does not have a layer direction. In this case, the blank sheet 200 may have a multi-layer structure or a single-layer structure.

[0022] In the blank sheet 200, the left side portion 13, the right side portion 14, the lower outer flap 50a and the upper outer flap 50c are connected to the front portion 11, the right side portion 14, the lower outer flap 50b and the upper outer flap 50d are connected to the back portion 15, the lower inner flap 20a and the upper inner flap 20c are connected to the left side portion 13, and the lower inner flap 20b and the upper inner flap 20d are connected to the right side portion 14. 5, the blank sheet 200 further includes an adhesive piece 250 connected to the left side surface portion 13. The adhesive piece 250 is adhered to the inner or outer surface of the back surface portion 15, whereby the body portion 10 is formed into an annular shape.

[0023] 5 to 10 are lines (first line 66 to fourth line 39 and folding lines 261 to 272, which will be described later). Each line (same as above) of the blank sheet 200 is a linear groove formed by pressing the back surface of the blank sheet 200 (the surface that will become the inner surface of the packaging box 100). The blank sheet 200 is folded at each of the creases (same as above) (a valley fold in FIG. 5). More specifically, the left side portion 13 and the front portion 11 are folded along folding line 269 so as to be perpendicular to each other at approximately 90°, the front portion 11 and the right side portion 14 are folded along folding line 270 so as to intersect each other at approximately 90°, and the right side portion 14 and the back portion 15 are folded along folding line 271 so as to be perpendicular to each other at approximately 90°. Furthermore, the adhesive piece 250 and the left side surface portion 13 are folded along a folding line 272 so as to be perpendicular to each other at approximately 90°. As described above, by inserting the lower insertion pieces 60a to 60d into the corresponding lower insertion slits 40a to 40d, the bottom surface portion 18, which is an opening / closing lid, is brought into a closed state (see FIG. 2), and the lower end opening of the body portion 10 is closed. Similarly, as described above, by inserting the upper insertion pieces 60e-60h into the corresponding upper insertion slits 40e-40h, the top surface portion 16 which is an opening / closing lid is brought into a closed state (see FIG. 1), and the upper end opening of the body portion 10 is closed. In this manner, the packaging box 100 is assembled. As an example, the packaging box 100 may be folded flat with the front portion 11 and left side portion 13, and the back portion 15 and right side portion 14 overlapping each other, as shown in Figure 6, and then distributed or stored, or it may be stored as a blank sheet 200.

[0024] In this embodiment, of the lower inner flaps 20a, 20b constituting the bottom surface portion 18 and the upper inner flaps 20c, 20d constituting the top surface portion 16, the lower inner flaps 20a, 20b are the above-mentioned inner flaps 20. Similarly, of the lower outer flaps 50a, 50b constituting the bottom surface portion 18 and the upper outer flaps 50c, 50d constituting the top surface portion 16, the lower outer flaps 50a, 50b are the above-mentioned outer flaps 50. The lower insertion slits 40a to 40d correspond to the insertion slit 40 described above, and the lower insertion pieces 60a to 60d correspond to the insertion piece 60 described above. According to this configuration, it is possible to satisfactorily maintain the engaged state between the lower inner flaps 20a, 20b and the lower outer flaps 50a, 50b that constitute the bottom portion 18. In other words, it is possible to satisfactorily maintain the closed state of the bottom portion 18 and more reliably prevent the bottom of the packaging box 100 from falling out.

[0025] The inner flaps 20 (lower inner flaps 20a, 20b) and the outer flaps 50 (lower outer flaps 50a, 50b) will be described in more detail below. In the following description, the lower inner flaps 20a, 20b may simply be referred to as inner flaps 20, and the lower outer flaps 50a, 50b may simply be referred to as outer flaps 50. Similarly, the lower insertion slits 40a-40d may simply be referred to as insertion slits 40, and the lower insertion pieces 60a-60d may simply be referred to as insertion pieces 60.

[0026] In this embodiment, the packaging box 100 includes a pair of left and right inner flaps 20 (lower inner flaps 20a, 20b) and a pair of front and rear outer flaps 50 (lower outer flaps 50a, 50b). The pair of left and right inner flaps 20 are formed symmetrically with respect to each other. The pair of front and rear outer flaps 50 are formed symmetrically with respect to the front and rear. In the following description, for convenience, one of the pair of left and right inner flaps 20 may be selectively illustrated and described. Similarly, in the following description, for convenience, one of the pair of front and rear outer flaps 50 may be selectively illustrated and described.

[0027] As shown in Figs. 5 and 7, each of the pair of left and right inner flaps 20 is formed in a rectangular shape that is long in the front-rear direction. In addition, the step direction of each of the pair of left and right inner flaps 20 is the left-right direction. More specifically, the inner flap body 21 of each of the pair of left and right inner flaps 20 (a portion of the inner flap 20 other than the first guide piece 30 and the second guide piece 36 and including the pressing portion 22) has a pair of front and rear first edges 211a, 211b extending parallel to the step direction (left-right direction) of the inner flap 20, and a pair of left and right second edges 212a, 212b extending parallel to the opposite step direction (front-rear direction) of the inner flap 20. Among them, the second edge 212b (see Fig. 7), which is the edge connected to the body 10, is the second swing axis AX2. That is, the second swing axis AX2 of the inner flap 20 extends parallel to the front-rear direction and therefore the opposite grain direction of the inner flap 20. In other words, in the case of this embodiment, the direction parallel to the second swing axis AX2 is the opposite grain direction of the inner flap 20, and the direction perpendicular to the second swing axis AX2 is the grain direction of the inner flap 20. Also, as shown in FIG. 5, folding lines 261, 263 are formed on the second swing axis AX2 (second edge 212b). However, in the present invention, the folding lines 261, 263 do not necessarily have to be formed on the second swing axis AX2 (second edge 212b). Each of the pair of front and rear outer flaps 50 is formed long in the left-right direction. In addition, the step direction of each of the pair of front and rear outer flaps 50 is the front-rear direction. More specifically, the outer flap main body 51 is a rectangular area in the outer flap 50 that is long in the opposite step direction (left-right direction) of the outer flap 50, and is defined by a pair of left and right first edges 511a, 511b extending parallel to the step direction (front-rear direction) of the outer flap 50, and a pair of front and rear second edges 512a, 512b extending parallel to the opposite step direction (left-right direction) of the outer flap 50. Among them, the second edge 512b (see FIG. 8), which is the edge connected to the body 10, is the first swing axis AX1. That is, the first swing axis AX1 of the outer flap 50 extends parallel to the left-right direction and therefore the opposite step direction of the outer flap 50. In other words, in the case of this embodiment, the direction parallel to the first swing axis AX1 is the anti-step direction of the outer flap 50, and the direction perpendicular to the first swing axis AX1 is the step direction of the outer flap 50. Also, as shown in Fig. 5, folding lines 262, 264 are formed on the first swing axis AX1 (second edge 512b). However, in the present invention, the folding lines 262, 264 do not necessarily have to be formed on the first swing axis AX1 (second edge 512b). In addition, in this embodiment, the first edge 53, which is the edge farther from the above-mentioned first swing axis AX1, is the edge on the second edge 512a side of the outer flap 50 (i.e., the edge opposite the first swing axis AX1 (second edge 512b)).

[0028] More specifically, as shown in FIG. 4, in this embodiment, the bottom surface portion 18 of the packaging box 100 has a pair of front and rear first swing axes AX1 and a pair of left and right second swing axes AX2. The pair of front and rear first oscillation axes AX1 are parallel to and face each other, and the pair of left and right second oscillation axes AX2 are parallel to and face each other. In addition, each of the pair of front and rear first oscillation axes AX1 is perpendicular to the pair of left and right second oscillation axes AX2. The pair of front and rear first oscillation axes AX1 and the pair of left and right second oscillation axes AX2 form an imaginary surface 310 having a rectangular shape in a plan view. Similarly, as shown in FIG. 3, the top surface 16 of the packaging box 100 has a pair of front and rear first swing shafts and a pair of left and right second swing shafts, and a virtual surface 320 having a rectangular shape in a plan view is formed by the pair of front and rear first swing shafts and the pair of left and right second swing shafts. The imaginary surface 310 of the bottom surface portion 18 and the imaginary surface 320 of the top surface portion 16 are parallel to and face each other in the up-down direction. Note that "parallel to and face each other" here means that the angle formed between the imaginary surface 310 of the bottom surface portion 18 and the imaginary surface 320 of the top surface portion 16 is less than 10°. 3, each of the imaginary surface 310 of the bottom surface portion 18 and the imaginary surface 320 of the top surface portion 16 faces parallel to a support surface 330 on which the packaging box 100 is placed. Note that "facing parallel to each other" here means that the angle between the imaginary surface 310 of the bottom surface portion 18 and the support surface 330 and the angle between the imaginary surface 320 of the top surface portion 16 and the support surface 330 are less than 10°. 3 and 4, for the sake of clarity, the dashed two-dot lines indicating the imaginary surfaces 310 and 320 are shown offset from the outline of the packaging box 100. However, in reality, the outline of the imaginary surface 310 is the same as the outline of the bottom surface 18 of the packaging box 100, and the outline of the imaginary surface 320 is the same as the outline of the top surface 16 of the packaging box 100 in a plan view.

[0029] In this embodiment, the insertion direction is a direction away from the first oscillation axis AX1 when the inner flap 20 is closed (see FIG. 4) so ​​as to follow the imaginary plane 310 formed by the first oscillation axis AX1 and the second oscillation axis AX2. More specifically, as an example, the insertion direction is a direction including both components of a direction away from the first swing axis AX1 and a direction intersecting the imaginary plane 310 (and thus the inner flap body 21). The insertion piece 60 is inserted from the outside of the packaging box 100 to the inside of the packaging box 100 through the insertion slit 40 in the insertion direction.

[0030] As described above, the inner flap 20 has the insertion slit 40. In the present embodiment, each of the pair of left and right inner flaps 20 has a pair of front and rear insertion slits 40 (lower insertion slits 40a to 40d). The pair of front and rear insertion slits 40 and their surrounding structures are set to have the same shape and dimensions as each other, and are arranged symmetrically with each other in the front and rear directions. In the following description, when describing the shape of the insertion slit 40 and its surrounding structure, for convenience, the shape of one of the lower insertion slits 40a to 40d and its surrounding structure may be selectively illustrated and described.

[0031] The insertion slit 40 penetrates the inner flap 20 in the thickness direction. In the present embodiment, the width dimension of the insertion slit 40 (the dimension in the direction perpendicular to the extension direction of the insertion slit 40) is substantially zero, and before the insertion piece 60 is inserted, both sides of the inner flap 20 through the insertion slit 40 are in contact with each other. However, in the present invention, the width dimension of the insertion slit 40 is not limited to this example, and it is sufficient if it is at least less than the thickness dimension of the inner flap 20.

[0032] As described above, the insertion slit 40 has a first slit 44 into which the insertion main body portion 62 is inserted, a second slit 46 into which the protruding piece 64 is inserted, and a first guide piece 30 arranged adjacent to the first slit 44 on the first oscillation axis AX1 side. Here, as shown in Figure 9, the inner flap 20 further has, for example, a second guide piece 36 arranged adjacent to the second slit 46 on the first oscillation axis AX1 side (the lower side of the paper in Figure 9), and a third slit 48 extending from a boundary 47 between the first slit 44 and the second slit 46 toward the first oscillation axis AX1 side. According to this configuration, the inner flap 20 has the second guide piece 36 disposed adjacent to the second slit 46 on the first swing axis AX1 side (the front side in the insertion direction). Therefore, during the insertion operation, the protruding piece 64 can be guided toward the second slit 46 by the second guide piece 36. Furthermore, the standing protruding piece 64 can be engaged with the second guide piece 36. Therefore, when the insertion piece 60 is unintentionally pulled in the pull-out direction, the standing protruding piece 64 abuts against the second guide piece 36, and it is possible to prevent the insertion piece 60 including the protruding piece 64 from coming out of the insertion slit 40. In addition, since the inner flap 20 has the third slit 48, when inserting the insertion piece 60, the opening 41 of the insertion slit 40 can expand inward at the formation area of ​​the second slit 46, the third slit 48 and the second guide piece 36 in the inner flap 20, that is, at the portion of the inner flap 20 corresponding to the protruding piece 64 (see FIG. 14(b)). Therefore, the protruding piece 64 can be smoothly inserted into the second slit 46. Furthermore, with this configuration, when processing the cardboard sheet into the shape of the blank sheet 200, the opening area of ​​the opening 41 of the insertion slit 40 formed can be minimized (effectively zero in this embodiment). In other words, the amount of cutting waste (punching waste) generated when forming the insertion slit 40 can be reduced. It should be noted that the present invention is not limited to this example, and the inner flap 20 may not have the third slit 48, for example.

[0033] In this embodiment, the first guide piece 30 is capable of swinging about a first guide piece swing axis AX3 that is located closer to the first swing axis AX1 than the first slit 44 is. Since the first guide piece 30 is swingable, during the insertion operation, the opening 41 of the insertion slit 40 can expand inward in the thickness direction at the formation area of ​​the third slit 48 and the second guide piece 36 in the inner flap 20, i.e., at the portion corresponding to the protruding piece 64 in the inner flap 20. Therefore, the insertion main body 62 can be smoothly inserted into the first slit 44. Furthermore, a portion of the first guide piece 30, at the end of the first guide piece 30 on the second slit 46 side, is a first guide piece protrusion 32 that protrudes in a direction away from the first guide piece oscillation axis AX3. Since the first guide piece 30 has the first guide piece protruding portion 32, when the insertion piece 60 is inserted into the insertion slit 40, the contact point between the first guide piece protruding portion 32 and the insertion piece 60 acts as a force point, and the first guide piece swing axis AX3 acts as a fulcrum. Therefore, a sufficient distance can be secured between the force point and the fulcrum in the insertion direction. Therefore, the first guide pieces 30 smoothly swing inward in accordance with the insertion operation. This makes it easier for the openings 41 of the insertion slits 40 to open inward in the thickness direction, making it easier to insert the insertion pieces 60 into the insertion slits 40. In addition, the end 46a of the second slit 46 on the first guide piece 30 side is positioned closer to the first guide piece swing axis AX3 than the end 32a of the first guide piece protrusion 32 on the side farther from the first guide piece swing axis AX3. With this configuration, at least the end 46a of the second slit 46, and therefore at least a portion of the pressing portion 22, is located closer to the insertion direction (towards the first guide piece swing axis AX3 and first swing axis AX1) in the front-to-rear direction than the tip edge portion of the first guide piece protrusion 32 (the end portion 32a farther from the first guide piece swing axis AX3). Therefore, when the insertion piece 60 is inserted into the insertion slit 40, first, the insertion piece 60 comes into contact with the tip edge portion (the end portion 32a on the side farther from the first guide piece swing axis AX3) of the first guide piece protruding portion 32 as the protruding piece 64 is inserted into the second slit 46. Therefore, when the protruding piece 64 is inserted into the second slit 46, the entire first guide piece 30 swings smoothly inward, making it easier for the opening 41 of the insertion slit 40 to open inward in the thickness direction. Here, "the end 46a of the second slit 46 on the first guide piece 30 side" refers to the end on the first guide piece 30 side in the extension direction of the second slit 46 (in this embodiment, the direction parallel to the first oscillation axis AX1).

[0034] More specifically, as shown in FIG. 10, in a direction perpendicular to the first oscillation axis AX1, it is preferable that the tip of the insertion main body 62 (the tip in the direction perpendicular to the first oscillation axis AX1) and the tip of the protruding piece 64 (same as above) are arranged at equivalent positions to each other. By doing this, at the timing when insertion of the protruding piece 64 into the second slit 46 begins and immediately thereafter, the insertion main body portion 62 and the tip edge portion (same as above) of the first guide piece protruding portion 32 come into contact, allowing the entire first guide piece 30 to swing smoothly inward.

[0035] Here, in the case of this embodiment, a portion of the inner flap 20 adjacent to the first guide piece protruding portion 32 on the side farther from the first oscillation axis AX1, i.e., a portion adjacent to the end of the first slit 44 on the second slit 46 side on the side farther from the first oscillation axis AX1, is the non-pressing portion 23. In the direction parallel to the first oscillation axis AX1, the protruding piece 64 is disposed at a position mainly corresponding to the pressing portion 22, and the insertion body portion 62 is disposed at a position mainly corresponding to the non-pressing portion 23. In this case, "non-pressing portion 23" does not necessarily mean a portion that does not press the insertion piece 60 at all when the insertion piece 60 is inserted into the insertion slit 40, but rather means a portion that has a smaller pressing force per unit width dimension (unit dimension in the direction parallel to the first oscillation axis AX1) than at least the pressing portion 22. It is preferable that the non-pressing portion 23 is not in contact with the insertion piece 60 (mainly the insertion main body portion 62) at least during a part of the process in which the insertion piece 60 is inserted into the insertion slit 40. In this way, interference between the non-pressing portion 23 and the insertion piece 60 is suppressed, and the insertion piece 60 can be smoothly inserted into the insertion slit 40. More specifically, in the case of this embodiment, at least at a part of the timing in the process of inserting the insertion piece 60 into the insertion slit 40, the protruding piece 64 is pressed inward by the pressing portion 22, while the insertion body portion 62 is inserted into the first slit 44 while pressing the first guide piece 30 inward. This causes the first guide piece 30 to swing inward, and the insertion piece 60 can be suppressed from being pressed outward (towards the non-pressing portion 23) by the first guide piece 30. Therefore, the non-pressing portion 23 can be made to be non-contact with the insertion piece 60. More specifically, in this embodiment, the non-pressing portion 23 is located further back than the pressing portion 22 in the insertion direction. Therefore, at the beginning of the insertion operation, the first guide piece 30 swings inward, so that the insertion body portion 62 and therefore the insertion piece 60 are not in contact with the non-pressing portion 23. Therefore, the insertion piece 60 can be smoothly inserted into the insertion slit 40.

[0036] Furthermore, in this embodiment, the inner flap 20 has a fourth ruled line 39 that constitutes the first guide piece pivot axis AX3. This allows the first guide piece 30 to smoothly swing inwardly about the first guide piece swing axis AX3. In the present invention, a part of the fourth ruled line 39 may be a slit. Furthermore, in the present invention, the fourth line 39 does not necessarily have to be formed on the inner flap 20, and for example, a folding line may be formed by the swinging of the first guide piece 30, and the folding line may constitute the first guide piece swing axis AX3.

[0037] In addition, a portion of the first guide piece 30, for example, at the end 30a (see Figure 9) of the first guide piece 30 that is farther from the first guide piece swing axis AX3, constitutes a second guide piece protrusion 34 that protrudes toward the second slit 46. According to this configuration, during the insertion operation, a portion of the first guide piece 30 (the second guide piece protruding portion 34) can be made to locally come into contact with the protruding piece 64. As a result, during the process of inserting the insertion piece 60 into the insertion slit 40, the protruding piece 64 is moderately restricted from standing up by contact (friction) between the inner surface of the protruding piece 64 and the outer surface of the second guide piece protruding portion 34, and the protruding piece 64 is made flat. As a result, the insertion piece 60 is smoothly inserted into the insertion slit 40. Furthermore, the elastic restoring force of the first guide piece 30 causes the second guide piece protrusion 34 to press the protrusion piece 64 outward. This makes it possible to more reliably regulate the standing of the protrusion piece 64 in the process of inserting the insertion piece 60 into the insertion slit 40. In addition, when the insertion piece 60 is inserted into the insertion slit 40, at least a portion of the second guide piece protruding portion 34 comes into contact (frictions) with the standing protruding piece 64, thereby preventing the protruding piece 64 from being pulled unintentionally in the pull-out direction. In other words, the protruding piece 64 and therefore the insertion piece 60 can be satisfactorily maintained in an engaged (locked) state with the insertion slit 40. Note that "while moderately restricting the rising of the protruding piece 64" here means restricting the rising of the protruding piece 64 to an extent that does not hinder the insertion of the insertion piece 60 into the insertion slit 40, and does not necessarily mean completely restricting the rising of the protruding piece 64. Moreover, the “elastic restoring force of the first guide piece 30 ” herein means the force that causes the first guide piece 30 to return to a flat state along the imaginary surface 310 . Also, "the protruding piece 64 is in a flat state" here means that the inclination angle of the protruding piece 64 relative to the insertion main body portion 62 is less than 30°, and preferably the inclination angle of the protruding piece 64 relative to the insertion main body portion 62 is less than 15°.

[0038] As shown in FIG. 14(a), the second guide piece is capable of swinging about a second guide piece swing axis AX4 that is located closer to the first swing axis AX1 than the second slit . Here, "the second guide piece oscillating axis AX4 is located closer to the first oscillating axis AX1 than the second slit 46" means that the second guide piece oscillating axis AX4 does not have a portion that protrudes from the second slit 46 on the side farther from the first oscillating axis AX1 in a direction perpendicular to the first oscillating axis AX1. According to this configuration, as the protruding piece 64 is inserted into the second slit 46, the second guide piece 36 is pressed from the outside by the protruding piece 64 that is about to stand up, and is thereby able to swing (open) inward. This allows the opening 41 of the insertion slit 40 to expand inward in the thickness direction in the formation area of ​​the second slit 46 and the second guide piece 36 in the inner flap 20, i.e., in the part of the inner flap 20 corresponding to the protruding piece 64, making it easier to insert the protruding piece 64 into the second slit 46, and therefore easier to insert the insertion piece 60 into the insertion slit 40. Furthermore, when the insertion of the protruding piece 64 into the second slit 46 is completed, the second guide piece 36 is in a state where there is substantially no area pressed inward by the protruding piece 64 (there is no such area at all or it is a very small area to the extent that no pressing force is generated by the protruding piece 64), and so is released from the pressure by the protruding piece 64 and swings outward due to its elastic restoring force to return to a flat state (a state along the imaginary surface 310). Therefore, the surface direction of the erected protruding piece 64 and the surface direction of the second guide piece 36 can intersect with each other, and the protruding piece 64 can be satisfactorily engaged with the second guide piece 36 as described above. It should be noted that the “elastic restoring force of the second guide piece 36 ” herein refers to the force that causes the second guide piece 36 to return to a flat state along the imaginary surface 310 . Also, the "flat state of the second guide piece 36" here means that the inclination angle of the second guide piece 36 relative to the inner flap main body 21 is less than 30°, and preferably the inclination angle of the second guide piece 36 relative to the inner flap main body 21 is less than 15°.

[0039] As shown in FIG. 9, the second guide piece swing axis AX4 is inclined, for example, in a direction approaching the first swing axis AX1 (downward in FIG. 9) as it approaches the first guide piece 30 side. As a result, as the protruding pieces 64 are inserted into the second slits 46, the second guide pieces 36 can swing smoothly inwardly about the second guide piece swing axis AX4 as a swing axis. In addition, in this embodiment, the second guide piece swing axis AX4 intersects with the step direction of the inner flap 20. This ensures an appropriate rigidity for the portion of the second guide piece 36 that constitutes the second guide piece swing axis AX4, and ensures a good elastic restoring force for the second guide piece 36. Therefore, after the insertion of the protruding piece 64 into the second slit 46 is completed, the second guide piece 36 can quickly return to a flat state. This allows the protruding piece 64 to be more reliably engaged with the second guide piece 36.

[0040] Furthermore, in this embodiment, the inner flap 20 has a second score 38 that constitutes the second guide piece swing axis AX4, and a portion of the second score 38 (in this embodiment, the middle portion described later) is a slit 26 (see Figure 9). This allows the second guide piece 36 to smoothly swing inwardly about the second guide piece swing axis AX4. More specifically, in this embodiment, the middle portion of the second ruled line 38 (the middle portion in the extension direction of the second ruled line 38) is a slit 26, and both ends of the second ruled line 38 (portions excluding the middle portion) are linear grooves. However, in the present invention, a portion of the second ruled line 38 does not have to be a slit 26, and the entire second ruled line 38 may be a linear groove. Furthermore, in the present invention, the second score line 38 does not necessarily have to be formed on the inner flap 20, and for example, a fold line may be formed by the swinging of the second guide piece 36, and the fold line may constitute the second guide piece swing axis AX4.

[0041] In this embodiment, a portion of the insertion slit 40 is disposed on the second oscillation axis AX2. 9, the first slit 44 extends from the second oscillation axis AX2 (the second edge 212b) in a direction away from the second oscillation axis AX2. More specifically, the first slit 44 includes a first straight portion 451, a first arc-shaped portion 452, a second straight portion 453, a second arc-shaped portion 454, a third straight portion 455, a third arc-shaped portion 456, and a fourth straight portion 457, which are arranged in this order from the second oscillation axis AX2 side. The first straight portion 451 extends linearly on the second swing axis AX2 (the second edge 212b). That is, the first straight portion 451 extends linearly in a direction parallel to the second swing axis AX2 (in this embodiment, in the opposite direction to the step of the inner flap 20). The second straight portion 453 extends linearly in a direction perpendicular to the second oscillation axis AX2 (in this embodiment, the step direction of the inner flap 20). The second straight portion 453 is located farther from the first oscillation axis AX1 than the first straight portion 451 in a direction parallel to the second oscillation axis AX2 (same as above), and is located farther from the second oscillation axis AX2 than the first straight portion 451 in a direction perpendicular to the second oscillation axis AX2 (same as above). Similarly, the third straight portion 455 extends linearly in a direction perpendicular to the second oscillation axis AX2 (same as above). The third straight portion 455 is located farther from the first oscillation axis AX1 than the second straight portion 453 in a direction parallel to the second oscillation axis AX2 (same as above), and is located farther from the second oscillation axis AX2 than the second straight portion 453 in a direction parallel to the second oscillation axis AX2 (same as above). The fourth straight portion 457 extends linearly in a direction parallel to the second oscillation axis AX2 (same as above). The fourth straight portion 457 is located closer to the first oscillation axis AX1 than the third straight portion 455 in the direction parallel to the second oscillation axis AX2 (same as above), and is located farther from the second oscillation axis AX2 than the third straight portion 455 in the direction perpendicular to the second oscillation axis AX2 (same as above). The first arc-shaped portion 452 gently connects the end of the first straight portion 451 opposite the first oscillation axis AX1 side to the end of the second straight portion 453 on the second oscillation axis AX2 side, and is formed in an arc shape that convexly extends diagonally upward to the left in Figure 9. The second arc-shaped portion 454 gently connects the end of the second straight portion 453 opposite the second oscillation axis AX2 side to the end of the third straight portion 455 on the second oscillation axis AX2 side, and is formed in an arc-like shape that convexly extends diagonally downward to the right in Figure 9. The third arc-shaped portion 456 gently connects the end of the third straight portion 455 opposite the second oscillation axis AX2 to the end of the fourth straight portion 457 opposite the first oscillation axis AX1, and is formed in an arc shape that convexly extends diagonally upward to the right in Figure 9. As described above, in the present invention, the insertion slit 40 only needs to have an imaginary line (not shown) connecting one end 42 and the other end 43 of the insertion slit 40 in a straight line extending in a direction that includes at least a component in the direction of the first oscillation axis AX1, and the insertion slit 40 may include portions (first straight portion 451 and fourth straight portion 457) that extend in a direction parallel to the second oscillation axis AX2, i.e., in a direction perpendicular to the first oscillation axis AX1. Furthermore, in the present invention, the position at which the insertion slit 40 is formed in the inner flap 20 is not limited to the above-mentioned example, and for example, the first straight portion 451 may be formed at a position offset from the second oscillation axis AX2 toward the second oscillation axis AX2.

[0042] The second slit 46 is mutually continuous with the first slit 44. More specifically, the second slit 46 extends linearly from the end of the fourth straight portion 457 on the first oscillation axis AX1 side in a direction perpendicular to the second oscillation axis AX2 (same as above). That is, in the case of this embodiment, the boundary 47 between the first slit 44 and the second slit 46 is the boundary (intersection) between the end of the fourth straight portion 457 on the first oscillation axis AX1 side and the end of the second slit 46 on the second oscillation axis AX2 side. In the present invention, the extension direction of the second slit 46 is not limited to this example, and for example, the second slit 46 may have a direction including both a component perpendicular to the second oscillation axis AX2 and a component parallel to the second oscillation axis AX2 (it may extend obliquely with respect to the first oscillation axis AX1).

[0043] The third slit 48 is mutually continuous with each of the first slit 44 and the second slit 46. More specifically, the third slit 48 extends from a boundary 47 between the fourth straight portion 457 of the first slit 44 and the second slit 46 toward the first oscillation axis AX1 side in a direction parallel to the second oscillation axis AX2 (same as above). More specifically, the third slit 48 includes an inclined portion 481 extending toward the first oscillation axis AX1 side from a boundary between an end of the fourth straight portion 457 on the first oscillation axis AX1 side and an end of the second slit 46 on the second oscillation axis AX2 side, and a straight portion 482 extending toward the first oscillation axis AX1 side from an end of the inclined portion 481 on the first oscillation axis AX1 side. The inclined portion 481 is linearly inclined toward the first oscillation axis AX1 side so as to gradually approach the second oscillation axis AX2. The straight portion 482 extends straight in a direction parallel to the second oscillation axis AX2 (same as above).

[0044] 9, in this embodiment, the first guide piece oscillation axis AX3 (fourth ruled line 39) is a straight line connecting the end of the first straight portion 451 on the first oscillation axis AX1 side and the end of the straight portion 482 on the first oscillation axis AX1 side. Moreover, the first guide piece oscillation axis AX3 extends parallel to the first oscillation axis AX1. The second guide piece swing axis AX4 (second ruled line 38) is a straight line connecting the end of the second slit 46 farther from the second swing axis AX2 side and the end of the third slit 48 on the first swing axis AX1 side, and is inclined linearly in the insertion direction so as to gradually move away from the first guide piece 30. With this configuration, the second guide piece 36 swings inward about the second guide piece swing axis AX4 as the swing axis, so that the opening 41 can be expanded in both the direction parallel to the first swing axis AX1 and the direction perpendicular to the first swing axis AX1 at the portion of the inner flap 20 corresponding to the protruding piece 64. Therefore, the protruding piece 64 can be inserted into the second slit 46 more smoothly.

[0045] 9 and other figures, the first guide piece 30 is directly connected to the inner flap body 21 with the first guide piece swing axis AX3 as the boundary. The outer shape of the portion of the first guide piece 30 that is not connected to the inner flap body 21 is defined by the first slit 44 and the third slit 48 described above.

[0046] The first guide piece protrusion 32 is, for example, a portion of the first guide piece 30 that protrudes in a direction away from the first guide piece oscillation axis AX3 beyond the second straight portion 453 of the first slit 44. The outer shape of the first guide piece protrusion 32 is defined by the second arc-shaped portion 454 and the third straight portion 455 of the first slit 44. More specifically, the outer shape of the end portion 32a of the first guide piece protrusion 32 on the side farther from the first guide piece oscillation axis AX3 is defined by the third straight portion 455, and extends linearly in a direction parallel to the first oscillation axis AX1. Also, the second guide piece protrusion 34 is, for example, a portion of the first guide piece 30 that is located farther from the second oscillation axis AX2 side than the straight portion 48 of the third slit 48. That is, in the case of this embodiment, the first guide piece protrusion 32 and the second guide piece protrusion 34 are partially overlapped with each other. The outer shape of the second guide piece protrusion 34 is defined by the third arc-shaped portion 456 and the fourth straight portion 457 of the first slit 44 and the inclined portion 481 of the third slit 48. The second slit 46 extends from the tip of the second guide piece protrusion 34 (the tip in the protruding direction of the second guide piece protrusion 34) toward the side farther from the second oscillation axis AX2 side in a direction perpendicular to the second oscillation axis AX2 (same as above). The third slit 48 extends from the tip of the second guide piece protruding portion 34 (the tip in the protruding direction of the second guide piece protruding portion 34) toward the first oscillation axis AX1 side.

[0047] In the present invention, the shape of the first slit 44 is not limited to the above example. That is, the shape of the first guide piece 30 is not limited to the above example, and the first guide piece 30 does not have to have the first guide piece protruding portion 32 or the second guide piece protruding portion 34, for example. In the present invention, the shape of the fourth ruled line 39 is not limited to the above-mentioned example, and the fourth ruled line 39 may be entirely or partially formed into a gently curved shape.

[0048] The second guide piece 36 is directly connected to the inner flap body 21 with the second guide piece swing axis AX4 as the boundary. The outer shape of the portion of the second guide piece 36 that is not connected to the inner flap body 21 is defined by the second slit 46 and the third slit 48 described above. More specifically, the outer shape of the edge 36a of the second guide piece 36 on the side farther from the first oscillation axis AX1 is defined by the second slit 46, and extends linearly in a direction perpendicular to the second oscillation axis AX2. The outer shape of the edge 36b of the second guide piece 36 on the second oscillation axis AX2 side is defined by the third slit 48, and includes a portion extending linearly in a direction parallel to the second oscillation axis AX2 (a portion defined by a straight portion 482) and a portion inclined linearly so as to gradually approach the second oscillation axis AX2 toward the first oscillation axis AX1 side (a portion defined by an inclined portion 481).

[0049] As shown in FIG. 9, the width dimension of the second guide piece 36 (the dimension in a direction parallel to the first oscillation axis AX1) gradually increases as it becomes farther away from the first oscillation axis AX1. Therefore, as the insertion of the protruding piece 64 into the second slit 46 progresses, the second guide piece 36 swings smoothly inward, and the width dimension (dimension in the direction parallel to the first swing axis AX1) of the opening 41 of the insertion slit 40 increases at the portion of the inner flap 20 corresponding to the protruding piece 64. Furthermore, with the above configuration, the edge 36a of the second guide piece 36 on the side farther from the first oscillation axis AX1, i.e., the width dimension of the portion of the second guide piece 36 with which the protruding piece 64 abuts, can be sufficiently secured. This ensures sufficient structural strength of the second guide piece 36 against forces in the pulling direction. Therefore, even if a pulling force acts unintentionally on the protruding piece 64 in the pulling direction while the protruding piece 64 is in contact with the second guide piece 36, the second guide piece 36 is prevented from being pressed inward by the protruding piece 64 and swinging again. In other words, the second guide piece 36 can more reliably restrict further movement of the protruding piece 64 in the pulling direction.

[0050] More specifically, the second guide piece 36 is formed, for example, in a substantially trapezoidal shape when viewed in a plane, and one of a pair of bases included in the substantially trapezoidal shape constitutes the second guide piece swing axis AX4 (second ruled line 38). However, in the present invention, the shape of the second guide piece 36 is not limited to this example, and the second guide piece 36 may be formed, for example, in a substantially triangular shape in a plan view.

[0051] In the present invention, the shapes of the second slit 46 and the third slit 48 are not limited to the above-mentioned examples, and may be, for example, a gently curved shape in whole or in part. That is, the second guide piece 36 may be, for example, a shape including a gently curved shape. Furthermore, in the present invention, the shape of the second ruled line 38 is not limited to the above-mentioned example, and the second ruled line 38 may be entirely or partially formed into a gently curved shape.

[0052] In this embodiment, the outer flap 50 has a pair of insertion pieces 60. One of the pair of insertion pieces 60 is disposed at one end 53a of the first edge portion 53, and the other of the pair of insertion pieces 60 is disposed at the other end 53b of the first edge portion 53. The packaging box 100 also has a first inner flap 20 having an insertion slit 40 into which one of the insertion pieces 60 is inserted, and a second inner flap 20 having an insertion slit 40 into which the other insertion piece 60 is inserted.

[0053] More specifically, each of the pair of front and rear outer flaps 50 has a pair of left and right insertion pieces 60 (lower insertion pieces 60a, 60b and lower insertion pieces 60c, 60d). The pair of left and right insertion pieces 60 are set to have the same shape and dimensions as each other and are arranged symmetrically with each other. More specifically, the left insertion piece 60 of the pair of left and right insertion pieces 60 is arranged at one end 53a of the first edge portion 53, and the right insertion piece of the pair of left and right insertion pieces 60 is arranged at the other end 53b of the first edge portion 53. The left insertion piece 60 is inserted into the insertion slit 40 of the left inner flap (lower inner flap 20a), and the right insertion piece 60 is inserted into the insertion slit 40 of the right inner flap 20 (lower inner flap 20b). However, in the present invention, the positional relationship of the insertion pieces 60 is not limited to this example, and the outer flap 50 may have, for example, a pair of insertion pieces 60 at the front and rear. In the following description, when describing the shape of the insertion piece 60, there are cases where, for convenience, one of the lower insertion pieces 60a to 60d is selectively illustrated and described.

[0054] The outer flap body 51 has, for example, a third line 54 between the first swing axis AX1 and the insertion piece 60, which extends parallel to the first swing axis AX1. 3 and 12(b), when inserting the insertion piece 60 into the insertion slit 40, the outer flap body 51 is bent outwardly in a convex shape along the third ruled line 54, and the insertion piece 60 is easily inclined relative to the inner flap 20. This makes it easy to move the insertion piece 60 in the insertion direction (a direction including both components of a direction away from the first oscillation axis AX1 and a direction intersecting the imaginary plane 310 (and thus the inner flap body 21)), so that the insertion operation can be performed smoothly. More specifically, as the bending angle of the outer flap body 51 (the angle between the portions of the outer flap body 51 passing through the third crease 54) increases, the insertion piece 60 moves in the insertion direction. Furthermore, as the bending angle (same as above) of the outer flap main body 51 decreases, the insertion piece 60 moves in the pull-out direction.

[0055] The third crease 54 extends linearly from the first edge 511a to the first edge 511b of the outer flap main body 51, for example. 5, in this embodiment, a third ruled line 54a extending parallel to the first swing axis AX1 is also formed on each of the upper outer flaps 50c, 50d constituting the top surface portion 16. Therefore, even when the top surface portion 16 is in the closed state, it is easy to insert the upper insertion pieces 60e-60h into the upper insertion slits 40e-40h.

[0056] As described above, the insertion piece 60 has an insertion main body portion 62 that is directly connected to the outer flap main body 51, and a protruding piece 64 that protrudes from the insertion main body portion 62 in a direction along the first pivot axis AX1 and is connected to the outer flap main body 51 via the insertion main body portion 62. 8, the insertion body 62 protrudes, for example, from a second edge 512a, which is an edge of the outer flap body 51 that is farther from the first swing axis AX1. More specifically, the insertion body 62 protrudes in a direction perpendicular to the first swing axis AX1 (in this embodiment, the step direction of the outer flap 50) in a direction away from the first swing axis AX1. That is, the insertion body 62 protrudes in a direction that includes a component of the insertion direction. The protruding piece 64 protrudes in a direction parallel to the first swing axis AX1 (in this embodiment, in the opposite step direction of the outer flap 50) toward the other insertion piece 60. In addition, a corner 64a of the protruding piece 64 on the side farther from the first swing axis AX1 is formed in a rounded corner shape (R chamfered shape). In this embodiment, the tip edge of the insertion body 62 and the tip edge of the protruding piece 64 form the tip edge 61a of the insertion piece 60 (the tip in the protruding direction of the insertion piece 60), and the base edge 62b of the insertion body 62 and the base edge 64b of the protruding piece 64 form the base edge 61b of the insertion piece 60 (the base end in the protruding direction of the insertion piece 60). A tip edge 61a of the insertion piece 60 extends linearly in a direction parallel to the first oscillation axis AX1 (same as above). A base edge 61b of the insertion piece 60 is inclined linearly so as to gradually move away from the first oscillation axis AX1 toward the protruding direction of the protruding piece 64 (the direction of arrow B shown in FIG. 10). An end 65 of the insertion piece 60 on the protruding direction side of the protruding piece 64 extends linearly in a direction perpendicular to the first oscillation axis AX1 (same as above). Further, at the corner of the insertion piece 60 opposite to the protruding piece 64 side, for example, a chamfered portion 68 is formed.

[0057] Here, a first crease 66 is formed at the boundary between the insertion body 62 and the protruding piece 64, and the first crease 66 is inclined toward the insertion body 62 (toward the opposite side to the protruding direction of the protruding piece 64) as it approaches the protruding direction of the insertion piece 60. In other words, in the insertion piece 60, the protruding piece 64 protrudes in a direction parallel to the first oscillation axis AX1 beyond the end of the first crease 66 on the first oscillation axis AX1 side. With this configuration, the protruding piece 64 can easily stand up using the first crease 66 as a folding line (swing axis). Furthermore, as the insertion operation of the insertion piece 60 into the insertion slit 40 progresses, the overlap between the first guide piece 30 and the protruding piece 64 decreases. As a result, in the early stage of the insertion operation, the protruding piece 64 is pressed down by the first guide piece 30 and the protruding piece 64 is prevented from standing up, making it easier to insert the protruding piece 64 into the second slit 46 (see Figures 12(a) and 12(b), etc.). On the other hand, in the later stage of the insertion operation, the protruding piece 64 stands up sufficiently and can be fully engaged with the second guide piece 36 (see Figures 16(a) and 16(b), etc.).

[0058] In the present invention, the first line 66 does not necessarily have to be formed at the boundary between the insertion body 62 and the protruding piece 64 . In this case, the protruding piece 64 needs only to protrude in a direction along the first swing axis AX1 (in this embodiment, on the side farther from the second swing axis AX2) than the intersection 71 between the base end edge 62b of the insertion main body portion 62 and the outer flap main body 51.

[0059] It is preferable that the first crease 66 extends in a direction intersecting the row direction (row direction of the outer flap 50), for example. This ensures good rigidity in the region where the first ruled line 66 is formed in the protruding piece 64. Therefore, the erection angle of the protruding piece 64 (the inclination angle of the protruding piece 64 relative to the insertion body portion 62) can be appropriately controlled, and the resistance of the insertion piece 60 to the insertion slit 40 during the insertion operation can be controlled.

[0060] More specifically, in this embodiment, the first line 66 extends linearly from the tip edge 61a to the base edge 61b of the insertion piece 60 as shown in FIG. In addition, the end of the first line 66 on the first swing axis AX1 side is positioned offset toward the protruding direction of the protruding piece 64 from the intersection 71 between the base end edge 62b of the insertion main body portion 62 and the outer flap main body 51. This allows the groove formed in the first score 66 in the insertion piece 60 to have a sufficient depth, as shown in Figure 19, making it easier for the protruding piece 64 to stand up with the first score 66 as the pivot axis. In the present invention, for example, a part or the entirety of the first score line 66 may be a slit. This also makes it easier for the protruding piece 64 to stand up with the first score line 66 as the pivot axis.

[0061] Furthermore, when the insertion piece 60 is inserted as deeply as possible into the insertion slit 40 (see Figure 15 (a)), it is preferable that the first line 66 and the end 34b on the protruding direction side of the protruding piece 64 on the first guide piece 30 overlap, or that the end 34b on the protruding direction side of the protruding piece 64 on the first guide piece 30 is positioned on the opposite side of the protruding direction of the protruding piece 64 from the first line 66. Note that the state where the insertion piece 60 is inserted as far as possible into the insertion slit 40 means a state where the tip of the insertion piece 60 is inserted as far as possible from the first swing axis AX1. In this state, the inner surface 51a of the outer flap main body 51 (i.e., the portion not inserted into the insertion slit 40) and the outer surface 30b of the first guide piece 30 interfere with each other in the thickness direction (press against each other), so that further insertion is restricted. According to this configuration, when the insertion piece 60 is inserted as deeply as possible into the insertion slit 40, the force with which the second guide piece protrusion 34 presses the protrusion piece 64 outward becomes essentially zero (is eliminated), so that the protrusion piece 64 can be more reliably erected. Here, "the first ruled line 66 overlaps with the end 34b of the protruding direction side of the protruding piece 64 of the first guide piece 30" means that the amount of misalignment between the first ruled line 66 and the end 34b of the protruding direction side of the protruding piece 64 of the first guide piece 30 in a plan view (when viewed in the normal direction of the imaginary plane 310) is within the range of the thickness of the blank sheet 200. In other words, the maximum amount of misalignment between the first ruled line 66 and the end 34b of the protruding direction side of the protruding piece 64 of the first guide piece 30 in a plan view (same as above) is the thickness dimension of the blank sheet 200.

[0062] As shown in FIGS. 8 and 10, the entire protruding piece 64 is separated from the outer flap main body 51, for example. With this configuration, interference between the protruding piece 64 and the outer flap main body 51 can be suppressed during the insertion operation, so that the insertion piece 60 can be easily tilted relative to the inner flap 20 and inserted into the insertion slit 40. More specifically, the entire base end edge 61b (see FIG. 10) of the insertion piece 60 including the protruding piece 64 is spaced apart from the outer flap body 51. This effectively prevents interference between the protruding piece 64 and the outer flap body 51 during the insertion operation.

[0063] 11(a), in the present embodiment, in the direction along the first oscillation axis AX1, the dimension W1 of the insertion slit 40 is equal to or larger than the dimension W2 of the insertion piece 60. Note that, here, the "direction along the first oscillation axis AX1" refers to a direction parallel to the first oscillation axis AX1. According to this configuration, there is no need to bend the insertion piece 60 in advance to match the dimensions of the insertion slit 40, and the insertion piece 60 can be inserted into the insertion slit 40 as is.

[0064] Moreover, in a direction parallel to the first oscillation axis AX1, it is preferable that the width dimension W3 (see FIG. 9) of the pressing portion 22 is, for example, equal to or larger than the maximum width dimension W4 (see FIG. 10) of the protruding piece 64. This ensures that the dimensions of the contact point between the protruding piece 64 and the pressing portion 22 are sufficient in the direction parallel to the first oscillation axis AX1, so that the protruding piece 64 can be pressed effectively by the pressing portion 22 and the protruding piece 64 can be more reliably erected.

[0065] 13(a), in a state where the insertion piece 60 is inserted into the insertion slit 40, the width dimension W5 of the first guide piece swing axis AX3 is larger than the distance L1 (the distance in a direction parallel to the first swing axis AX1) between the end 65 of the protruding piece 64 of the insertion piece 60 on the protruding direction side and the end 34b of the protruding piece 64 of the first guide piece 30 on the protruding direction side. Preferably, the distance L1 is about 1 / 3 of the width dimension W5. Note that the distance L1 is the width dimension (the dimension in a direction parallel to the first swing axis AX1) of the part of the protruding piece 64 that is not in contact with the second guide piece protruding portion 34. According to this configuration, the width dimension W5 of the first guide piece pivot shaft AX3 can be sufficiently ensured, so that the elastic restoring force of the first guide piece 30 can be satisfactorily obtained. In addition, during the insertion operation, the width dimension of the portion of the protruding piece 64 that is not in contact with the second guide piece protruding portion 34 can be made appropriately small, that is, the width dimension (same as above) of the contact point between the protruding piece 64 and the second guide piece protruding portion 34 can be appropriately secured. Therefore, in the process of inserting the insertion piece 60 into the insertion slit 40, the insertion body portion 62 is pressed outward by the elastic restoring force of the first guide piece 30, and the inclination angle of the insertion body portion 62 with respect to the inner flap body 21 can be sufficiently suppressed. Also, the force with which the second guide piece protruding portion 34 presses the protruding piece 64 outward can be sufficiently ensured, and the pressing force can be favorably applied to the protruding piece 64. Thus, the standing of the protruding piece 64 can be appropriately restricted. This allows the insertion piece 60 to be smoothly inserted into the insertion slit 40, and allows the protruding piece 64, out of the insertion main body portion 62 and the protruding piece 64, to locally stand up well. More specifically, in the case of this embodiment, in the process of inserting the insertion piece 60 into the insertion slit 40, the maximum inclination angle of the insertion main body portion 62 with respect to the inner flap main body 21 is preferably less than 30°. In addition, in the case of this embodiment, in the process of inserting the protruding piece 64 into the second slit 46, the maximum inclination angle of the protruding piece 64 with respect to the insertion body portion 62 is preferably less than 30°.

[0066] Here, in the case of this embodiment, at the first edge portion 53 of the outer flap 50, between one insertion piece 60 and the other insertion piece 60 (in this embodiment, between the left insertion piece 60 and the right insertion piece 60), a pressing piece 57 is formed which protrudes from the outer flap main body 51 in a direction away from the first swing axis AX1 and presses the first inner flap 20 and the second inner flap 20 (in this embodiment, the left lower inner flap 20a and the right lower inner flap 20b) inward (inward). At least a portion of the edge 571 of the pressing piece 57 farther from the first oscillation axis AX1 (in this embodiment, a middle portion 571c, which will be described later) extends parallel to the first oscillation axis AX1. According to this configuration, as shown in Fig. 20(a), the pressing piece 57 can be in good line or surface contact with both of the lower inner flaps 20a, 20b, so that as shown in Fig. 20(b) and Fig. 20(c), it is possible to prevent the lower inner flaps 20a, 20b from bending outward due to the load of the contents 400. In other words, it is possible to prevent the bottom of the packaging box 100 from falling out. More specifically, in this embodiment, the entire intermediate portion 571c (excluding both end portions 571a, 571b described later) of the edge 571 of the pressing piece 57 on the side farther from the first swing axis AX1 extends parallel to the first swing axis AX1 and is perpendicular to the second swing axis AX2 of the inner flap 20. This makes it possible to prevent the lower inner flaps 20a, 20b from swinging about the second swing axis AX2 and being put into an open state due to the load of the contents 400. That is, the bottom of the packaging box 100 can be more reliably prevented from falling out.

[0067] Moreover, each of the two edges 572a, 572b of the pressing piece 57 in the direction along the first oscillation axis AX1 extends, for example, in a direction perpendicular to the first oscillation axis AX1. According to this configuration, interference between the insertion piece 60 and the pressing piece 57 during the insertion operation can be suppressed, so that the insertion piece 60 can be smoothly inserted into the insertion slit 40.

[0068] Each of the two edge portions 572a, 572b of the pressing piece 57 in the direction along the first oscillation axis AX1 is spaced apart from the insertion piece 60, for example, in the direction along the first oscillation axis AX1. According to this configuration, interference between the insertion piece 60 and the pressing piece 57 during the insertion operation can be suppressed, so that the insertion piece 60 can be smoothly inserted into the insertion slit 40.

[0069] In this embodiment, both ends 571a, 571b of the edge 571 of the pressing piece 57 on the side farther from the first oscillation axis AX1 are rounded (chamfered). This prevents the pressing piece 57 from getting caught on the inner flap 20 during the insertion operation, so that the pair of insertion pieces 60 can be smoothly slid and inserted into the corresponding insertion slits 40. In this embodiment, both end portions 571a are formed in an arc shape that protrudes obliquely upward to the left in FIG. 8, and both end portions 571b are formed in an arc shape that protrudes obliquely upward to the right in FIG.

[0070] More specifically, it is preferable that the radius of curvature R1 (see Figure 10) of both end portions 571a, 571b of the edge of the pressing piece 57 on the side farther from the first oscillation axis AX1 is larger than the radius of curvature R2 (see Figure 10) of the corner 64a of the protruding piece 64 (the curvature of both end portions 571a, 571b of the edge of the pressing piece 57 on the side farther from the first oscillation axis AX1 is smaller than the curvature of the corner 64a of the protruding piece). By doing so, it is possible to more reliably prevent the pressing piece 57 from getting caught on the inner flap 20. In addition, it is preferable that the radius of curvature R1 of both end portions 571a, 571b of the edge of the pressing piece 57 on the side farther from the first oscillation axis AX1 is larger than the radius of curvature R3 (see Figure 9) of the corner 34a of the second guide piece protrusion 34 (the curvature of both end portions 571a, 571b of the edge of the pressing piece 57 on the side farther from the first oscillation axis AX1 is smaller than the curvature of the corner 34a of the second guide piece protrusion 34). This also makes it possible to more reliably prevent the pressing piece 57 from getting caught on the inner flap 20.

[0071] Moreover, each of the two edges 572a, 572b of the pressing piece 57 in the direction along the first oscillation axis AX1 extends, for example, in a direction perpendicular to the first oscillation axis AX1. This allows the insertion piece 60 to be smoothly inserted into the insertion slit 40 all the way to the back in the insertion direction.

[0072] Further, each of the two edge portions 572a, 572b of the pressing piece 57 in the direction along the first pivot axis AX1 is spaced apart from the insertion piece 60 in the direction along the first pivot axis AX1. This makes it possible to prevent the protruding piece 64 from getting caught on both edges 572a, 572b of the pressing piece 57 when the protruding piece 64 stands up.

[0073] More specifically, in this embodiment, both edge portions 572a, 572b of the pressing piece 57 extend linearly in a direction perpendicular to the first swing axis AX (the step direction of the outer flap 50). In addition, each of the two edges 572a, 572b of the pressing piece 57 is spaced apart from the tip edge of the second guide piece protrusion 34 (the end 65 on the protruding direction side of the protruding piece 64 in the first guide piece 30) in the direction of the first swing axis AX1 (the opposite step direction of the outer flap 50).

[0074] An example of the operation when inserting the insertion piece 60 into the insertion slit 40 will be described below with reference to Fig. 12(a) to Fig. 17. The description will start from the stage where the body 10 of the packaging box 100 is assembled into a rectangular ring shape, while the bottom part 18 is in an open state (the inner flap 20 and the outer flap 50 are not engaged with each other). Fig. 12(a), Fig. 13(a), Fig. 14(a), Fig. 15(a), and Fig. 16(a) are plan views of the insertion slit 40 and the surrounding structure of the insertion piece 60 as viewed from the inside surface side of the packaging box 100. In addition, the bending angle of the outer flap main body 51, the rising angle of the protruding piece 64 (the inclination angle of the protruding piece 64 relative to the insertion main body portion 62), and the insertion depth of the insertion piece 60 into the insertion slit 40 at each stage of the insertion operation shown in Figures 12(a) to 17 are merely examples, and may differ from the states shown in Figures 12(a) to 17 depending on the thickness of the blank sheet 200 and the dimensions of each part of the packaging box 100.

[0075] First, the outer flap body 51 is folded along the third line 54 so as to be convex outward (toward the bottom in FIG. 12(b)). More specifically, the bending angle of the outer flap body 51 is adjusted so that the tip of the insertion piece 60 is positioned closer to the first swing axis AX1 than the insertion slit 40 and the insertion piece 60 is inclined relative to the insertion slit 40. Then, the insertion operation of inserting the insertion piece 60 into the insertion slit 40 is started. More specifically, the insertion body 62 is disposed so as to be in surface or line contact mainly with the outer surface of the first guide piece 30, and then the insertion body 62 is moved along the first guide piece 30 in the insertion direction toward the first slit 44. Similarly, the protruding piece 64 is disposed so as to be in surface or line contact mainly with the outer surface of the second guide piece 36, and then the protruding piece 64 is moved along the second guide piece 36 in the insertion direction toward the second slit 46. As a result, as shown in FIG. 12(a), first, the leading edge (leading edge in the insertion direction) of the insertion body 62 reaches the second straight portion 453 (see FIG. 9) of the first slit 44, and the leading edge (leading edge in the insertion direction) of the protruding piece 64 reaches the second slit 46.

[0076] 13(a) and 13(b), the insertion operation is continued until the tip edge 61a of the insertion piece 60 reaches the end 32a of the first guide piece protruding portion 32. As a result, mainly the tip of the insertion body 62 is inserted into the first slit 44. In addition, during this process, the contact point between the first guide piece protruding portion 32 and the insertion piece 60 acts as a force point as described above, so the first guide piece 30 can swing inward smoothly. This makes it easier for the opening 41 of the insertion slit 40 to open inward in the thickness direction, making it easier to insert the insertion body 62 into the first slit 44. Furthermore, as described above, in the first slit 44, the second arc-shaped portion 454 is formed between the second straight portion 453 and the third straight portion 455 (see FIG. 9). Therefore, when the tip edge 61a of the insertion piece 60 is moved from the second straight portion 453 to the third straight portion 455, i.e., when the tip edge 61a moves along the first guide piece protruding portion 32, it is possible to prevent the tip edge 61a from being caught on the corner portion (second arc-shaped portion 454) between the second straight portion 453 and the third straight portion 455. Furthermore, mainly the tip of the protruding piece 64 is inserted into the second slit 46, and a part of the tip comes into contact with the pressing portion 22 and is pressed inward by the pressing portion 22. At this time, as the protruding piece 64 is inserted into the second slit 46 as described above, the second guide piece 36 swings inward. 13(b), in this embodiment, a portion of the protruding piece 64 is in line contact with the base end edge (the edge defined by the second slit 46) of the pressing portion 22. However, in the present invention, the contact of the protruding piece 64 with the pressing portion 22 may be surface contact or point contact.

[0077] Next, as shown in FIGS. 14(a) and 14(b), the insertion operation is continued until the tip edge 61a of the insertion piece 60 is positioned further back than the end portion 32a of the first guide piece protruding portion 32 in the insertion direction. As a result, mainly up to the middle portion of the insertion body portion 62 is inserted into the first slit 44 , and mainly up to the middle portion of the protruding piece 64 is inserted into the second slit 46 .

[0078] 15(a) and 15(b), the insertion piece 60 is inserted into the insertion slit 40 until it is inserted to the deepest extent. As a result, most of the insertion body 62 is inserted into the first slit 44. Similarly, the entire protruding piece 64 is inserted into the second slit 46, and the protruding piece 64 stands up sufficiently. Also, the second guide piece 36 is released from the pressure of the protruding piece 64, and becomes flat due to the elastic restoring force. Although Figure 15(b) shows the outer flap main body 51 in a bent state, this is merely one example, and when the insertion piece 60 is inserted as deeply as possible into the insertion slit 40, the outer flap main body 51 may be flat (the bending angle of the outer flap main body 51 is substantially 180°) and may be in face contact with the inner flap 20.

[0079] Then, when the insertion operation is completed, the insertion piece 60 moves slightly in the pull-out direction due to the elastic restoring force of the outer flap main body 51. As a result, as shown in Figures 16(a) and 16(b), the base end edge 64b (the edge on the front side in the insertion direction) of the erected protruding piece 64 abuts against the tip edge of the second guide piece 36 (the edge portion 36a on the side of the second guide piece 36 farther from the first swing axis AX1). In this way, the insertion piece 60 engages with the insertion slit 40. In this state, even if the insertion piece 60 is unintentionally pulled in the pull-out direction, the base end edge 64b of the protruding piece 64 and the tip edge of the second guide piece 36 (the edge portion 36a of the second guide piece 36 on the side farther from the first swing axis AX1) interfere with each other, restricting further movement of the protruding piece 64 in the pull-out direction. In other words, the state in which the protruding piece 64 is engaged with the second slit 46 is maintained. 17, the end face 35 of the protruding piece 64 of the first guide piece 30 on the protruding direction side can be made to contact the inner surface of the protruding piece 64 that stands up, so that the frictional force generated between the end face 35 and the protruding piece 64 can make the protruding piece 64 engage with the second slit 46 better. Furthermore, when the insertion piece 60 is engaged with the insertion slit 40, the first ruled line 66 is inclined in the pulling direction so as to approach the end 34b of the protruding piece 64 of the first guide piece 30 on the protruding direction side. Therefore, as the insertion piece 60 moves in the pulling direction, the frictional force generated between the protruding piece 64 and the end face 35 can be increased. Therefore, it is possible to more reliably prevent the protruding piece 64 from unintentionally coming out of the second slit 46. In this way, even if the insertion piece 60 is unintentionally pulled in the direction of removal from the insertion slit 40, the state in which the insertion piece 60 is engaged with the insertion slit 40 can be satisfactorily maintained.

[0080] Thus, according to this embodiment, the insertion piece 60 can be easily inserted into the insertion slit 40, while after the insertion piece 60 is inserted into the insertion slit 40, the insertion piece 60 can maintain a good engagement with the insertion slit 40.

[0081] Here, as described above, the first guide piece 30 has the second guide piece protruding portion 34. Then, at the portion of the protruding piece 64 that contacts the second guide piece protruding portion 34, a force that causes the second guide piece protruding portion 34 to press the protruding piece 64 outward is applied due to the elastic restoring force of the first guide piece 30. In addition, in this embodiment, the first line 66 formed at the boundary between the insertion body portion 62 and the protruding piece 64 as described above is inclined toward the insertion body portion 62 as it moves in the protruding direction of the insertion piece 60. According to this configuration, the width dimension (dimension in a direction parallel to the first oscillation axis AX1) of the contact point between the second guide piece protruding portion 34 and the protruding piece 64 gradually decreases as the insertion operation of the insertion piece 60 into the insertion slit 40 progresses. This makes it possible to gradually reduce the force with which the second guide piece protruding portion 34 presses the protruding piece 64 outward as the insertion operation of the insertion piece 60 into the insertion slit 40 progresses.

[0082] More specifically, at the beginning of the insertion operation (see Figs. 13(a) and 13(b)), in a plan view, the entire second guide piece protrusion 34 is located, for example, on the protruding direction side of the protruding piece 64 from the first ruled line 66. This makes the width dimension of the contact point between the second guide piece protrusion 34 and the protruding piece 64 the maximum. This allows the force with which the second guide piece protruding portion 34 presses the protruding piece 64 outward to be balanced with the force with which the pressing portion 22 presses the protruding piece 64 inward, or the force with which the second guide piece protruding portion 34 presses the protruding piece 64 outward to be greater than the force with which the pressing portion 22 presses the protruding piece 64 inward. Therefore, since the protruding piece 64 is sufficiently prevented from standing up in the early stage of the insertion operation, the entire protruding piece 64 can be smoothly inserted into the second slit 46 from the middle stage (see FIG. 14(a)) to the later stage (see FIG. 16(a)) of the subsequent insertion operation.

[0083] Next, in the middle of the insertion operation (see FIGS. 14(a) and 14(b)), in a plan view, the second guide piece protrusion 34 is positioned to straddle the boundary (first ruled line 66) between the insertion main body 62 and the protrusion piece 64. That is, in a plan view, a part of the second guide piece protrusion 34 overlaps with the protrusion piece 64, while the other part of the second guide piece protrusion 34 overlaps with the insertion main body 62. As a result, the width dimension of the contact point between the second guide piece protrusion 34 and the protrusion piece 64 becomes smaller compared to the early stage of the insertion operation. As a result, the force with which the pressing portion 22 presses the protruding piece 64 inward exceeds the force with which the second guide piece protruding portion 34 presses the protruding piece 64 outward, and the protruding piece 64 starts to stand up. In the present invention, the timing at which the protruding piece 64 starts to stand is not limited to this example. For example, the protruding piece 64 may start to stand at a later stage of the insertion operation described below.

[0084] Then, in a later stage of the insertion operation (see Figures 15(a) and 15(b)), in a plan view, the tip edge of the second guide piece protrusion 34 (the end 65 of the protrusion piece 64 on the first guide piece 30 in the protruding direction) is positioned so as to overlap with the first ruled line 66. In other words, in a plan view, substantially the entire second guide piece protrusion 34 overlaps with the insertion main body portion 62, not with the protrusion piece 64. As a result, the width dimension of the contact point between the second guide piece protrusion 34 and the protrusion piece 64 is essentially zero. As a result, the force with which the second guide piece protruding portion 34 presses the protruding piece 64 outward becomes substantially zero (is eliminated). Meanwhile, the force with which the pressing portion 22 presses the protruding piece 64 inward is maintained. Therefore, the entire protruding piece 64 can be made to stand up sufficiently, so that the insertion piece 60 engages well with the insertion slit 40 after the insertion operation is completed. It should be noted that the present invention is not limited to this example, and in the latter stage of the insertion operation, the leading edge of the second guide piece protruding portion 34 (the end 65 of the protruding piece 64 of the first guide piece 30 in the protruding direction side) is arranged at a position overlapping with the first ruled line 66 in a plan view. In other words, substantially the entire second guide piece protruding portion 34 may be configured to overlap with the insertion body portion 62 instead of the protruding piece 64 in a plan view. Even with this configuration, the entire protruding piece 64 can be made to stand up sufficiently.

[0085] The present invention is not limited to the above-described embodiment, and includes various modifications and improvements as long as the object of the present invention is achieved.

[0086] For example, in the above embodiment, an example has been described in which only the bottom surface portion 18 of the packaging box 100 has the inner flap 20 and the outer flap 50, but the present invention is not limited to this example, and it is sufficient that any one or more of the multiple planar portions (for example, the above-mentioned front surface portion 11, left side surface portion 13, right side surface portion 14, back surface portion 15, top surface portion 16, and bottom surface portion 18) of the packaging box 100 have the inner flap 20 and the outer flap 50. That is, in the present invention, for example, only the top surface portion 16 of the packaging box 100 may have the inner flap 20 and the outer flap 50, or the top surface portion 16 and the bottom surface portion 18 may each have the inner flap 20 and the outer flap 50.

[0087] In addition, in the above-mentioned embodiment, an example was described in which the packaging box 100 has four insertion slits 40 and four insertion pieces 60. However, in the present invention, the number of each of the insertion slits 40 and insertion pieces 60 possessed by the packaging box 100 is not particularly limited, and it is sufficient that the number of insertion slits 40 and the number of insertion pieces 60 are at least the same as each other.

[0088] In addition, in the above-mentioned embodiment, an example was described in which the packaging box 100 has a pair of left and right inner flaps 20 and a pair of front and rear outer flaps 50. However, in the present invention, the positional relationship between the inner flaps 20 and the outer flaps 50 is not limited to this example, and the packaging box 100 may have, for example, a pair of front and rear inner flaps 20 and a pair of left and right outer flaps 50.

[0089] In the present invention, the insertion slit 40 and its surrounding structure (the first guide piece 30 and the second guide piece 36) may have a positional relationship different from that of the above embodiment (for example, a positional relationship inverted from left to right). In this case, the positional relationship between the insertion body 62 and the protruding piece 64 of the insertion piece 60 also has a positional relationship different from that of the above embodiment (for example, a positional relationship inverted from left to right) so as to correspond to the positional relationship between the first slit 44 and the second slit 46 of the insertion slit 40.

[0090] In the above embodiment, an example has been described in which the first guide piece protrusion 32 and the second guide piece protrusion 34 partially overlap each other, but the present invention is not limited to this example, and the first guide piece protrusion 32 and the second guide piece protrusion 34 may be formed (arranged) separately (without overlapping each other). That is, in the present invention, when the first guide piece 30 includes both the first guide piece protrusion 32 and the second guide piece protrusion 34, the first guide piece protrusion 32 and the second guide piece protrusion 34 partially overlap each other, or the first guide piece protrusion 32 and the second guide piece protrusion 34 are formed separately.

[0091] Furthermore, the various components of the packaging box 100 do not need to be independent entities individually, and it is acceptable for multiple components to be formed as a single member, for one component to be formed from multiple members, for one component to be part of another component, or for part of one component to overlap with part of another component, etc.

[0092] The present embodiment encompasses the following technical ideas. (1) A packaging box having an inner flap having an insertion slit, and an outer flap having an insertion piece to be inserted into the insertion slit and arranged to overlap the outer side of the inner flap, The insertion slit extends in a direction along a first pivot axis which is a pivot axis of the outer flap, The outer flap has an outer flap body including the first swing shaft, The insertion piece is disposed on a first edge portion of the outer flap that is an edge portion farther from the first swing shaft, and protrudes from the outer flap body in a direction away from the first swing shaft, The insertion piece has an insertion body portion directly connected to the outer flap body, and a protruding piece protruding from the insertion body portion in a direction along the first swing shaft and connected to the outer flap body via the insertion body portion, The insertion slit has a first slit into which the insertion body portion is inserted and a second slit into which the protruding piece is inserted, the inner flap has a first guide piece disposed adjacent to the first slit on the first pivot shaft side, A packaging box in which the portion of the inner flap adjacent to the second slit on the side farther from the first pivot axis serves as a pressing portion that presses the protruding piece in the thickness direction when the insertion piece is inserted into the insertion slit. (2) The packaging box described in (1), wherein the inner flap has a second guide piece arranged adjacent to the second slit on the first pivot axis side, and a third slit extending from the boundary between the first slit and the second slit toward the first pivot axis side. (3) A packaging box as described in (1) or (2), in which the dimension of the insertion slit in the direction along the first pivot axis is greater than or equal to the dimension of the insertion piece. (4) A first crease is formed at the boundary between the insertion body and the protruding piece, The packaging box according to any one of (1) to (3), wherein the first line is inclined toward the insertion body as it approaches the protruding direction of the insertion piece. (5) When the insertion piece is inserted as deeply as possible into the insertion slit, The first ruled line and an end of the first guide piece on a protruding direction side of the protruding piece overlap each other, Or, The packaging box according to (4), wherein the end of the first guide piece on the protruding direction side of the protruding piece is located on the opposite side of the first line in the protruding direction of the protruding piece. (6) The packaging box is a cardboard box, The packaging box according to (4) or (5), wherein the first crease extends in a direction intersecting with the row direction. (7) A packaging box according to any one of (1) to (6), wherein the entire protruding piece is spaced apart from the outer flap body. (8) The first guide piece is rotatable about a first guide piece pivot shaft that is located closer to the first pivot shaft than the first slit, a first guide piece protruding portion protruding in a direction away from the first guide piece pivot shaft at an end portion of the first guide piece on the second slit side, A packaging box as described in any one of (1) to (7), wherein the end of the second slit on the first guide piece side is positioned closer to the first guide piece swing shaft than the end of the first guide piece protruding portion that is farther from the first guide piece swing shaft. (9) The first guide piece is rotatable about a first guide piece pivot shaft that is located closer to the first pivot shaft than the first slit, A packaging box as described in any one of (1) to (8), wherein a portion of the first guide piece is a second guide piece protruding portion that protrudes toward the second slit at the end of the first guide piece that is farther from the first guide piece pivot axis. (10) A packaging box according to any one of (1) to (9), wherein the second guide piece is capable of swinging about a second guide piece swing shaft that is located closer to the first swing shaft than the second slit. (11) The packaging box according to (10), wherein the second guide piece pivot shaft is inclined in a direction approaching the first pivot shaft as it approaches the first guide piece. (12) The inner flap has a second crease that constitutes the second guide piece pivot axis, The packaging box according to (11), wherein a portion of the second line is a slit. (13) The outer flap has a pair of the insertion pieces, One of the pair of insertion pieces is disposed at one end of the first edge portion, The other of the pair of insertion pieces is disposed at the other end of the first edge portion, The packaging box includes a first inner flap having the insertion slit into which the one insertion piece is inserted, and a second inner flap having the insertion slit into which the other insertion piece is inserted, At the first edge portion, a pressing piece is formed between the one insertion piece and the other insertion piece, protruding from the outer flap body in a direction away from the first swing shaft and pressing the first inner flap and the second inner flap inwardly, The packaging box according to (1) or (2), wherein at least a portion of the edge of the pressing piece on the side farther from the first swing shaft extends parallel to the first swing shaft. (14) The outer flap has a pair of the insertion pieces, One of the pair of insertion pieces is disposed at one end of the first edge portion, The other of the pair of insertion pieces is disposed at the other end of the first edge portion, The packaging box includes a first inner flap having the insertion slit into which the one insertion piece is inserted, and a second inner flap having the insertion slit into which the other insertion piece is inserted, At the first edge portion, a pressing piece is formed between the one insertion piece and the other insertion piece, protruding from the outer flap body in a direction away from the first swing shaft and pressing the first inner flap and the second inner flap inwardly, The packaging box according to (1) or (2), wherein each of the two edges of the pressing piece in the direction along the first swing axis extends in a direction perpendicular to the first swing axis. (15) The outer flap has a pair of the insertion pieces, One of the pair of insertion pieces is disposed at one end of the first edge portion, The other of the pair of insertion pieces is disposed at the other end of the first edge portion, The packaging box includes a first inner flap having the insertion slit into which the one insertion piece is inserted, and a second inner flap having the insertion slit into which the other insertion piece is inserted, At the first edge portion, a pressing piece is formed between the one insertion piece and the other insertion piece, protruding from the outer flap body in a direction away from the first swing shaft and pressing the first inner flap and the second inner flap inwardly, A packaging box as described in (1) or (2), wherein each of the two edges of the pressing piece in a direction along the first swing axis is spaced apart from the insertion piece in a direction along the first swing axis.

[0093] In the above, an example was described in which the packaging box 100 essentially comprises the first slit 44 and the second slit 46 of the insertion slit 40, the insertion body portion 62 and the protruding piece 64 of the insertion piece 60, and the pressing portion 22. However, the present invention is not limited to this example, and the packaging box 100 may be configured as to whether or not it comprises these. That is, this embodiment is as follows: <1> from <4> It also includes the technical ideas of <1> A packaging box having an inner flap having an insertion slit, and an outer flap having an insertion piece to be inserted into the insertion slit and arranged to overlap the outer side of the inner flap, The insertion slit extends in a direction along a first pivot axis which is a pivot axis of the outer flap, The outer flap has an outer flap body including the first swing shaft, The insertion piece is disposed on a first edge portion of the outer flap that is an edge portion farther from the first swing shaft, and protrudes from the outer flap body in a direction away from the first swing shaft, The outer flap has a pair of the insertion pieces, One of the pair of insertion pieces is disposed at one end of the first edge portion, The other of the pair of insertion pieces is disposed at the other end of the first edge portion, The packaging box includes a first inner flap having the insertion slit into which the one insertion piece is inserted, and a second inner flap having the insertion slit into which the other insertion piece is inserted, At the first edge portion, a pressing piece is formed between the one insertion piece and the other insertion piece, protruding from the outer flap body in a direction away from the first swing shaft and pressing the first inner flap and the second inner flap inwardly, A packaging box, in which at least a portion of the edge of the pressing piece remote from the first swing shaft extends parallel to the first swing shaft. <2> Both ends of the edge of the pressing piece farther from the first swing shaft are rounded. <1> The packaging box described in. <3> Each of the two edges of the pressing piece in the direction along the first oscillation axis extends in a direction perpendicular to the first oscillation axis. <1> or <2> The packaging box described in. <4> Each of the two edge portions of the pressing piece in the direction along the first pivot shaft is spaced apart from the insertion piece in the direction along the first pivot shaft. <1> from <3> The packaging box described in. [Explanation of symbols]

[0094] 10. Torso 11 Front part 13 Left side part 14 Right side part 15 Back part 16 Top section 18 Bottom part 19 Containment Area 20 Inner flap 20a, 20b Lower inner flap 20c, 20d Upper inner flap 21 Inner flap body 211a, 211b 1st edge 212a, 212b second edge 22 Pressing section 23 Non-pressure part 26 Slit 30 First guide piece 30a: End portion farther from the first guide piece pivot shaft 30b External surface 32 First guide piece protrusion 32a: End portion farther from the first guide piece pivot shaft 34 Second guide piece protrusion 34a Corner 34b End of the protruding piece on the protruding direction side 35 End face of protruding piece on the protruding direction side 36 Second guide piece 36a: the edge of the second guide piece on the side farther from the first swing shaft 36b: Edge of the second guide piece on the second swing shaft side 38 Second Ruled Line 39 Fourth Ruled Line 40 Insertion slit 40a~40d Lower insertion slit 40e~40h Upper insertion slit 41 Aperture 42 one end 43 Other end 44 First Slit 451 1st straight section 452 1st arc part 453 2nd straight section 454 Second arc 455 3rd straight section 456 Third arc 457 4th straight line section 46 Second Slit 46a First guide, one side 47 Boundary 48 3rd Slit 481 Slope 482 Straight section 50 Outer flap 50a, 50b Lower outer flap 50c, 50d upper outer flap 51 Outer flap body 51a Inside 511a, 511b 1st edge 512a, 512b 2nd edge 53 First edge 53a One end 53b Other end 54, 54a Third line 57 Pressing piece 571 Margin 571a, 571b both ends 571c middle part 572a, 572b both edges 60 Insert 60a~60d Lower insert 60e~60h Upper insert 61a Tip edge 61b Proximal edge 62 Insertion body 62b proximal edge 64 Projecting piece 64a Corner 64b Proximal edge 65 End of the protruding piece on the protruding direction side 66 First Ruled Line 68 Chamfered section 71 Intersection of base edge of insert body and outer flap body 100 Packaging boxes (cardboard boxes) 200 Blank Sheets (Packaging Box Configuration Sheets) 250 Adhesive piece 261~272 Folding lines 280th step 310 Temporary surface of bottom part 320 Temporary surface of the top 330 Placement surface 400 Contents AX1 First swing axis AX2 Second oscillation axis AX3 First guide single swing shaft AX4 Second guide single swing shaft L1: Distance between the end of the protruding piece of the insertion piece on the protruding direction side and the end of the second guide piece protruding part on the protruding direction side R1: Radius of curvature of both ends of the edge of the pressing piece farther from the first oscillation axis R2 Radius of curvature of the corner of the protruding piece W1 Insertion slit dimensions W2 Insert Piece Dimensions W3 Width of pressing part W4 Maximum width of protruding piece W5 Width of the first guide single swing shaft

Claims

1. A packaging box having an inner flap having an insertion slit, and an outer flap having an insertion piece to be inserted into the insertion slit and arranged to overlap the outer side of the inner flap, The insertion slit extends in a direction along a first pivot axis which is a pivot axis of the outer flap, The outer flap has an outer flap body including the first swing shaft, The insertion piece is disposed on a first edge portion of the outer flap that is an edge portion farther from the first pivot shaft, and protrudes from the outer flap body in a direction away from the first pivot shaft, The insertion piece has an insertion body portion directly connected to the outer flap body, and a protruding piece protruding from the insertion body portion in a direction along the first swing shaft and connected to the outer flap body via the insertion body portion, The insertion slit has a first slit into which the insertion body portion is inserted and a second slit into which the protruding piece is inserted, The inner flap has a first guide piece disposed adjacent to the first slit on the first pivot shaft side, In the packaging box, the portion of the inner flap adjacent to the second slit on the side farther from the first pivot axis serves as a pressing portion that presses the protruding piece in the thickness direction when the insertion piece is inserted into the insertion slit.

2. 2. The packaging box according to claim 1, wherein the inner flap has a second guide piece arranged adjacent to the second slit on the first pivot axis side, and a third slit extending from the boundary between the first slit and the second slit toward the first pivot axis side.

3. 3. The packaging box according to claim 1, wherein a dimension of the insertion slit in a direction along the first pivot shaft is equal to or greater than a dimension of the insertion piece.

4. A first crease is formed at the boundary between the insertion body and the protruding piece, The packaging box according to claim 1 or 2, wherein the first lines are inclined toward the insertion body as they extend in a direction in which the insertion pieces protrude.

5. When the insertion piece is inserted as deeply as possible into the insertion slit, The first ruled line and an end of the first guide piece on a protruding direction side of the protruding piece overlap with each other, Or, The packaging box according to claim 4 , wherein the end of the first guide piece in the protruding direction of the protruding piece is located on the opposite side of the first line in the protruding direction of the protruding piece.

6. The packaging box is a cardboard box, The packaging box according to claim 4, wherein the first crease extends in a direction intersecting with a column direction.

7. 3. The packaging box according to claim 1, wherein the entire projecting piece is spaced apart from the outer flap body.

8. the first guide piece is capable of swinging about a first guide piece swing shaft that is located closer to the first swing shaft than the first slit, a first guide piece protruding portion protruding in a direction away from the first guide piece pivot shaft at an end portion of the first guide piece on the second slit side, The packaging box according to claim 1 or 2, wherein the end of the second slit on the first guide piece side is positioned closer to the first guide piece pivot axis than the end of the first guide piece protruding portion that is farther from the first guide piece pivot axis.

9. the first guide piece is capable of swinging about a first guide piece swing shaft that is located closer to the first swing shaft than the first slit, A packaging box as described in claim 1 or 2, wherein a portion of the first guide piece is a second guide piece protruding portion that protrudes toward the second slit at the end of the first guide piece that is farther from the first guide piece pivot axis.

10. 3. The packaging box according to claim 1, wherein the second guide piece is capable of swinging about a second guide piece swing shaft that is located closer to the first swing shaft than the second slit.

11. The packaging box according to claim 10, wherein the second guide piece pivot shaft is inclined in a direction approaching the first pivot shaft as it approaches the first guide piece side.

12. The inner flap has a second crease that constitutes the second guide piece pivot axis, The packaging box according to claim 11, wherein a portion of the second crease is a slit.

13. The outer flap has a pair of the insertion pieces, One of the pair of insertion pieces is disposed at one end of the first edge portion, The other of the pair of insertion pieces is disposed at the other end of the first edge portion, The packaging box includes a first inner flap having an insertion slit into which the one insertion piece is inserted, and a second inner flap having an insertion slit into which the other insertion piece is inserted, At the first edge portion, a pressing piece is formed between the one insertion piece and the other insertion piece, protruding from the outer flap body in a direction away from the first swing shaft and pressing the first inner flap and the second inner flap inwardly, 3. The packaging box according to claim 1, wherein at least a portion of an edge of the pressing piece on a side farther from the first pivot shaft extends parallel to the first pivot shaft.

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