Packaging box

Abstract

To provide a packaging box having a high joining strength and less apt to be made improperly.SOLUTION: A packaging box 1 comprises: a cylindrical body 11 having a back board 22, a side board 23, a front board 24 and a side board 25 continuing in a rectangular cylindrical form; flaps 223, 233, 243 and 253 extending from one ends of the back board 22, side board 23, front board 24 and side board 25; a coupling piece 244 extending from the flap 223 toward the flap 233 through a fold line 622 and joined at a back surface to a main surface of the flap 233; and a coupling piece 224 extending from the flap 243 toward the flap 253 through a fold line 642 and joined at a back surface to a main surface of the flap 253. The coupling piece 224 has a swell portion 224a as a first swell portion swelling toward the flap 223 greater than the fold line 622, and the coupling piece 244 has a swell portion 244a as a second swell portion swelling toward the flap 243 greater than the fold line 642.SELECTED DRAWING: Figure 22

Description

[Technical field]

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

[0002] Patent Document 1 describes a bottom-lock type packaging box in which the bottom lid can be assembled with one touch. As shown in FIG. 1, such a packaging box is formed from one blank sheet, and a side wall 91, a front wall 92, a side wall 93, a rear wall 94, and a connecting piece 95 are connected in sequence from the right side of the drawing. The side wall 91, the front wall 92, the side wall 93, the rear wall 94, and the connecting piece 95 are each separated by a fold a. A second bottom wall component piece 911, a first bottom wall component piece 921, a second bottom wall component piece 931, and a first bottom wall component piece 941 are respectively extended from the lower end edges of the side wall 91, the front wall 92, the side wall 93, and the rear wall 94 via a fold b. Furthermore, a substantially triangular connecting piece 922 is extended from the first bottom wall component piece 921 near the second bottom wall component piece 911 via a diagonal fold c. Similarly, a substantially triangular connecting piece 942 extends from the first bottom wall constituent piece 941 toward the second bottom wall constituent piece 931 via a diagonal fold c.

[0003] When assembling the blank sheet, first, as shown in FIG. 2, the first and second bottom wall constituent pieces 911, 921, 931, and 941 are folded forward at 180° at the fold b. Next, as shown in FIG. 3, the connecting pieces 922 and 942 are folded backward at 180° at the fold c. Next, glue B is applied to the back surface of the connecting piece 942, and then, as shown in FIG. 4, the rear wall 94 is folded forward at 180° at the fold a, and the back surface of the connecting piece 942 is attached to the front surface of the second bottom wall constituent piece 931. Next, glue B is applied to the front surface of the connecting piece 95 and the back surface of the connecting piece 922, and then, as shown in FIG. 5, the side wall 91 is folded forward at 180° at the fold a, and the back surface of the side wall 91 is attached to the front surface of the connecting piece 95, and the front surface of the second bottom wall constituent piece 911 is attached to the back surface of the connecting piece 922. As a result of the above, a folded packaging box is obtained.

[0004] Then, when the side wall 91, the front wall 92, the side wall 93, and the rear wall 94 are folded 90° from the folded state at the crease a to form a rectangular cylindrical body, the first and second bottom wall constituent pieces 911, 921, 931, 941 and the connecting pieces 922, 942, which were folded so as to overlap each other in the folded state, are unfolded into flat plates to form the bottom lid. With this configuration, the bottom lid is formed at the same time as the cylindrical body is formed from the folded state, making it easy to assemble the packaging box. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2013-209114 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the packaging box of Patent Document 1, the fold c that separates the first bottom wall constituent piece 921 and the connecting piece 922 is formed linearly. The same is true for the fold c that separates the first bottom wall constituent piece 941 and the connecting piece 942. Therefore, it is difficult to secure a large area for the connecting pieces 922, 942, and for example, the amount (area) of glue B applied to the connecting pieces 922, 942 is reduced, and the strength of the bottom cover is reduced accordingly. In addition, the glue B is likely to overflow from the connecting pieces 922, 942, and the overflowing glue B causes the connecting piece 922 to stick to the first bottom wall constituent piece 921 or the front wall 92 located directly below it, or the connecting piece 942 to stick to the first bottom wall constituent piece 941 or the rear wall 94 located directly below it.

[0007] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a packaging box that can ensure a large area for the connecting pieces and can prevent a reduction in the amount of glue applied and the applied glue from spilling out. [Means for solving the problem]

[0008] These objects can be achieved by the present invention described below in (1) to (4).

[0009] (1) A cylindrical body having a first side panel, a second side panel, a third side panel, and a fourth side panel arranged in a rectangular cylindrical shape; a first flap, a second flap, a third flap and a fourth flap extending from one end of the first side panel, the second side panel, the third side panel and the fourth side panel; A first connecting piece extending from the first flap to the second flap side via a first fold line and having a back surface joined to a front surface of the second flap; A second connecting piece is provided extending from the third flap to the fourth flap side via the second fold line, and the back surface is joined to the front surface of the fourth flap, The first connecting piece has a first bulging portion that bulges toward the first flap side from the first fold line, The second connecting piece has a second bulging portion that bulges toward the third flap side beyond the second fold line.

[0010] (2) In the folded state, the first side panel, the first flap, the first connecting piece, the second flap and the second side panel are folded over each other, The packaging box according to (1) above, wherein the third side panel, the third flap, the second connecting piece, the fourth flap and the fourth side panel are folded over one another.

[0011] (3) A first cut that defines an outline of the first bulge is formed at a boundary between the first flap and the first connecting piece, and the first bulge appears by folding the first connecting piece relative to the first flap at the first fold line, A packaging box as described in (1) above, in which a second notch that forms the outline of the second bulge is formed at the boundary between the third flap and the second connecting piece, and the second bulge appears by folding the second connecting piece against the third flap at the second fold line.

[0012] (4) The packaging box according to (1) above, wherein the first bulge and the second bulge are each curved in an arc shape. Effect of the Invention

[0013] According to this invention, since the first connecting piece has a first bulge, the area of ​​the first connecting piece can be increased accordingly. Therefore, the amount of glue applied to the first connecting piece can be increased, and the bonding strength with the second flap can be increased. In addition, the glue is less likely to spill out from the first connecting piece. Similarly, since the second connecting piece has a second bulge, the area of ​​the second connecting piece can be increased accordingly. Therefore, the amount of glue applied to the second connecting piece can be increased, and the bonding strength with the fourth flap can be increased. In addition, the glue is less likely to spill out from the second connecting piece. Therefore, a packaging box with high bonding strength and less likely to have manufacturing defects is obtained. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a development view of a conventional packaging box as seen from the front side. [Diagram 2] FIG. 2 is a plan view illustrating a method for assembling the packing box shown in FIG. [Diagram 3] FIG. 2 is a plan view illustrating a method for assembling the packing box shown in FIG. [Figure 4] FIG. 2 is a plan view illustrating a method for assembling the packing box shown in FIG. [Diagram 5] FIG. 2 is a plan view illustrating a method for assembling the packing box shown in FIG. [Figure 6] 1 is a development view of a packaging box according to a preferred embodiment, seen from the front side. [Figure 7] 13 is an enlarged plan view showing a flap and a connecting piece extending from the lower end of the front panel. FIG. [Figure 8] 13 is an enlarged plan view showing the state in which the flap and connecting piece extending from the lower end of the front panel are folded. FIG. [Figure 9] 13 is an enlarged plan view showing a flap and a connecting piece extending from the lower end of the rear panel. FIG. [Figure 10]13 is an enlarged plan view showing a state in which a flap and a connecting piece extending from a lower end portion of the rear panel are folded. FIG. [Figure 11] 13 is an enlarged plan view showing a modified example of the connecting piece. FIG. [Figure 12] 13 is an enlarged plan view showing a modified example of the connecting piece. FIG. [Figure 13] 13 is an enlarged plan view showing a modified example of the connecting piece. FIG. [Figure 14] 13 is an enlarged plan view showing a modified example of the connecting piece. FIG. [Figure 15] 7 is a plan view illustrating a method for assembling the packing box shown in FIG. 6. [Figure 16] 7 is a plan view illustrating a method for assembling the packing box shown in FIG. 6. [Figure 17] 7 is a plan view illustrating a method for assembling the packing box shown in FIG. 6. [Figure 18] 7 is a plan view illustrating a method for assembling the packing box shown in FIG. 6. [Figure 19] 7 is a plan view illustrating a method for assembling the packing box shown in FIG. 6. [Figure 20] 7 is a plan view illustrating a method for assembling the packing box shown in FIG. 6. [Figure 21] FIG. 7 is a perspective view illustrating a method for assembling the packing box shown in FIG. 6. [Figure 22] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] As shown in Fig. 6, the packaging box 1 of this embodiment is formed by assembling box-body forming pieces 10 which are integrally formed by punching out one blank sheet such as paper. The blank sheet may be made of any material, and suitable materials include white cardboard, resin-laminated paper, aluminum-laminated paper, and aluminum-deposited paper.

[0016] In the following, for convenience of explanation, a folding method in which the front surface of the box-forming piece 10 is convex is also referred to as a "normal folding", and a folding method in which the back surface is convex is also referred to as a "reverse folding". In addition, the upper side in Fig. 1 is referred to as "top" and the lower side is referred to as "bottom".

[0017] 6 is a development view of box-forming piece 10 as viewed from the front. As shown in the figure, box-forming piece 10 has a laterally connected adhesive piece 21, a back panel 22 as a first side panel, a side panel 23 as a second side panel, a front panel 24 as a third side panel, and a side panel 25 as a fourth side panel. The paired back panel 22 and front panel 24 have approximately the same shape, and the paired side panel 23 and side panel 25 also have approximately the same shape.

[0018] Additionally, the glue strip 21, the back panel 22, the side panel 23, the front panel 24, and the side panel 25 are separated by fold lines 31, 32, 33, and 34 extending vertically. Specifically, the glue strip 21 and the back panel 22 are separated by fold line 31, the back panel 22 and the side panel 23 are separated by fold line 32, the side panel 23 and the front panel 24 are separated by fold line 33, and the front panel 24 and the side panel 25 are separated by fold line 34.

[0019] Flaps 231, 251 extend from the upper ends of the side panels 23, 25. The side panel 23 and the flap 231 are separated by a fold line 53 extending in the horizontal direction, and the side panel 25 and the flap 251 are separated by a fold line 55 extending in the horizontal direction.

[0020] Meanwhile, flaps 233 and 253 serving as second and fourth flaps are extended from the lower ends of the side panels 23 and 25. The side panel 23 and the flap 233 are separated by a fold line 63 extending in the horizontal direction, and the side panel 25 and the flap 253 are separated by a fold line 65 extending in the horizontal direction.

[0021] Additionally, a top cover plate 241 extends from the upper end of the front panel 24. The front panel 24 and the top cover plate 241 are separated by a fold line 541 extending in the horizontal direction. Additionally, an insertion piece 242 extends from the upper end of the top cover plate 241. The top cover plate 241 and the insertion piece 242 are separated by a fold line 542 extending in the horizontal direction.

[0022] Meanwhile, a flap 243 as a third flap is extended from the lower end of the front panel 24. The front panel 24 and the flap 243 are separated by a fold line 641 extending in the horizontal direction. As shown in FIG. 7, the flap 243 is an asymmetric trapezoid, and the angle of inclination of the oblique side 243a on the flap 253 side with respect to the fold line 641 is smaller than that of the oblique side 243b on the flap 233 side. In other words, the flap 243 is gently inclined. In addition, a locking notch 243c is formed in the middle of the oblique side 243a for locking the bottom lid when the packaging box 1 is assembled as described later.

[0023] Furthermore, a connecting piece 244 serving as a second connecting piece is extended from the flap 243 toward the flap 253. The connecting piece 244 is connected to a base portion of the flap 243. The flap 243 and the connecting piece 244 are separated by a fold line 642 serving as a second fold line extending in an oblique direction. For ease of explanation, the fold line 642 is shown by a chain line in FIG. 7.

[0024] Further, a cut 245 is formed as a second cut at the boundary between the flap 243 and the connecting piece 244, overlapping with the fold line 642. The cut 245 is cut in an arc shape (C-shape) that opens on the connecting piece 244 side and convex toward the flap 243 side. This cut 245 forms a bulging portion 244a in the connecting piece 244 that bulges beyond the fold line 642 toward the flap 243 side. With this configuration, the bulging portion 244a can be easily formed.

[0025] 8, when assembling the box-forming piece 10, the flap 243 is folded forward at 180° to the front panel 24 at the fold line 641, and further, the connecting piece 244 is folded backward at 180° to the flap 243 at the fold line 642, and glue B is applied to the back surface of the connecting piece 244. Therefore, by forming the bulging portion 244a in the connecting piece 244 to secure a large area, the amount (area) of glue B that can be applied to the connecting piece 244 increases, and the adhesion strength can be increased accordingly. Furthermore, the applied glue B is less likely to protrude from the connecting piece 244, and the connecting piece 244 is less likely to stick to the flap 243 or the front panel 24 that is stacked underneath it.

[0026] In addition, by forming the bulging portion 244a in an arc shape as in this embodiment, the bulging portion 244a is less likely to bend, and when the connecting piece 244 is folded relative to the flap 243 at the fold line 642, the bulging portion 244a is more likely to stand up.

[0027] 6, a flap 223 serving as a first flap is extended from the lower end of the back panel 22. The back panel 22 and the flap 223 are separated by a fold line 621 extending in the horizontal direction. As shown in FIG. 9, the flap 223 is an asymmetric trapezoid, and the angle of inclination of the oblique side 223a on the flap 233 side with respect to the fold line 621 is smaller than that of the oblique side 223b on the opposite side. In addition, a locking notch 223c is formed midway along the oblique side 223a for locking the bottom lid when the packaging box 1 is assembled as described below.

[0028] Furthermore, a connecting piece 224 serving as a first connecting piece is extended from the flap 223 toward the flap 233. The connecting piece 224 is connected to a base portion of the flap 223. The flap 223 and the connecting piece 224 are separated by a fold line 622 serving as a first fold line extending in an oblique direction. For ease of explanation, the fold line 622 is shown by a chain line in FIG. 9.

[0029] Further, a cut 225 is formed as a first cut at the boundary between the flap 223 and the connecting piece 224, overlapping with the fold line 622. The cut 225 is cut in an arc shape (C-shape) that opens on the connecting piece 224 side and convex toward the flap 223 side. Such a cut 225 forms a bulging portion 224a in the connecting piece 224 that bulges beyond the fold line 622 toward the flap 223 side. With such a configuration, the bulging portion 224a can be easily formed.

[0030] When assembling the box-forming piece 10, as shown in Fig. 10, the flap 223 is folded forward at 180° to the back panel 22 at the fold line 621, and further, the connecting piece 224 is folded backward at 180° to the flap 223 at the fold line 622, and glue B is applied to the back surface of the connecting piece 224. Therefore, by forming the bulging portion 224a in the connecting piece 224 to secure a large area, the amount (area) of glue B that can be applied to the connecting piece 224 increases, and the adhesion strength can be increased accordingly. Furthermore, the applied glue B is less likely to protrude from the connecting piece 224, and the connecting piece 224 is less likely to stick to the flap 223 or the back panel 22 stacked below it.

[0031] In addition, by forming the bulging portion 224a in an arc shape as in this embodiment, the bulging portion 224a is less likely to bend, and when the connecting piece 224 is folded relative to the flap 223 at the folding line 622, the bulging portion 224a is more likely to stand up.

[0032] The configuration of the box-body forming piece 10 has been described above. However, the configuration of the box-body forming piece 10 is not limited to this. In particular, the configuration of the bulging portions 224a, 244a is not particularly limited, and several modified examples are given below. Note that since the bulging portions 224a, 244a have the same configuration, the bulging portion 224a will be described below as a representative, and the description of the bulging portion 244a will be omitted.

[0033] 11, a linear cut 227 is formed extending from the approximate center (apex) of the cut 225 toward the flap 223. With this configuration as well, when the connecting piece 224 is folded along the fold line 622 toward the flap 223, the bulge 224a is easily raised.

[0034] 12, in addition to the configuration of FIG 11, both end portions of the cut 225 are curved in an arc shape toward the flap 223 side. The radius of curvature of both end portions is smaller than the radius of curvature of the center portion.

[0035] In the example shown in FIG. 13, the notch 225 is bent in a rectangular shape so as to protrude toward the flap 223. Specifically, the notch 225 has both ends extending on the fold line 622, and the center portion extending on the flap 223 approximately parallel to the fold line 622. The ends and the center portion are connected to each other by a line extending in a direction perpendicular to the fold line 622. With this configuration, the bulge 224a is rectangular, and it is easier to form the bulge 224a larger than in the case of the arc shape as in this embodiment. Furthermore, in the example shown in FIG. 13, a pair of linear notches 228 are formed extending from both ends of the center portion of the notch 225 toward the flap 223. By forming the pair of notches 228, the bulge 224a is easier to stand up when the connecting piece 224 is folded along the fold line 622 relative to the flap 223.

[0036] In the example shown in FIG. 14, the notch 225 extends on the flap 223 substantially parallel to the fold line 622. Furthermore, a pair of notches 229 are formed so as to intersect both ends of the notch 225. Each notch 229 extends from above the fold line 622 toward the flap 223, and is curved in an arc shape so that the base end side (connecting piece 224 side) of the intersection with the notch 225 spreads outward. With this configuration, the bulging portion 224a becomes trapezoidal, and it is easier to form the bulging portion 224a larger than the case of the arc shape as in this embodiment. In addition, since the tip of each notch 229 extends further from the intersection with the notch 225, when the connecting piece 224 is folded at the fold line 622 relative to the flap 223, the bulging portion 224a is easily raised.

[0037] Although several modified examples have been given above, the configuration of the bulging portion 224a is not particularly limited.

[0038] Next, a method of assembling the box-forming pieces 10 to form the packaging box 1 will be described. First, as shown in Fig. 15, the box-forming piece 10 is turned over, and the flaps 223, 233, 243, and 253 are folded forward at 180° along the fold lines 621, 63, 641, and 65, respectively. Next, as shown in Fig. 16, the connecting pieces 224 and 244 are folded backward at 180° along the fold lines 622 and 642, respectively. As a result, the flap 223 and the connecting piece 224 are folded over the back panel 22, and the flap 243 and the connecting piece 244 are folded over the front panel 24.

[0039] Next, as shown in FIG. 17, glue B is applied to the back surface of the connecting piece 224, and then, as shown in FIG. 18, the back panel 22 is folded 180° along the fold line 32, and the back surface of the connecting piece 224 is attached to the front surface of the flap 233. Here, as described above, the connecting piece 224 has the bulging portion 224a that bulges outward from the fold line 622, so that the area of ​​the connecting piece 224 can be increased accordingly. Therefore, the amount (area) of glue B that can be applied to the connecting piece 224 increases, and the adhesive strength between the connecting piece 224 and the flap 233 can be increased accordingly. Furthermore, the applied glue B is less likely to protrude from the connecting piece 224, and the connecting piece 224 is less likely to stick to the flap 223 or the back panel 22 that is stacked underneath it.

[0040] Next, as shown in FIG. 19, glue B is applied to the front surface of the glue strip 21 and the back surface of the connecting piece 244, and then, as shown in FIG. 20, the side panel 25 is folded 180° along the fold line 34, and the back surface of the side panel 25 is attached to the front surface of the glue strip 21, and the front surface of the flap 253 is attached to the back surface of the connecting piece 244. At this time, the glue strip 21 is folded carefully so that it is inserted between the flap 253 and the side panel 25. Here, as described above, the connecting piece 244 has a bulging portion 244a that bulges outward from the fold line 642, so that the area of ​​the connecting piece 244 can be increased accordingly. Therefore, the amount (area) of glue B that can be applied to the connecting piece 244 increases, and the adhesion strength between the connecting piece 244 and the flap 253 can be increased accordingly. Furthermore, the applied glue B is less likely to overflow from the connecting piece 244, and the connecting piece 244 is less likely to stick to the flap 243 or the front panel 24 placed underneath it.

[0041] In this manner, the box-forming piece 10 is folded in a folded state. However, the procedure for folding the box-forming piece 10 is not limited to the above procedure.

[0042] In addition, in the folded state, the parts extending from the lower end of the cylindrical body 11, that is, the flap 223, the connecting piece 224, the flap 233, the flap 243, the connecting piece 244, and the flap 253, are hidden inside the cylindrical body 11. This results in a compact folded state.

[0043] In the folded box-forming piece 10, the back panel 22, the flap 223, the connecting piece 224, the flap 233, and the side panel 23 are overlapped at the lower end, and similarly, the front panel 24, the flap 243, the connecting piece 244, the flap 253, and the side panel 25 are overlapped at the lower end. In this way, in the box-forming piece 10, the blank sheet is folded five times, so if the blank sheet is too thick, it will not be able to be folded neatly as the folding proceeds, and unnecessary parts may be bent, wrinkles may be formed in unnecessary parts, or the position may be shifted when pasting, which may decrease the aesthetics of the packaging box 1. Furthermore, if you try to fold it forcibly, the blank sheet may be torn and damaged, or excessive stress may be applied to the pasted part, causing the pasted part to peel off. Therefore, the yield of the packaging box 1 decreases. Hereinafter, such problems are also collectively referred to as "defects".

[0044] Therefore, the thickness of the blank sheet is not particularly limited, but is preferably 1.0 mm or less, and more preferably 0.5 mm or less, for example. This makes it difficult for the above-mentioned problems to occur even when the blank sheet is folded five times, and effectively suppresses the deterioration of aesthetics and yield.

[0045] In order to verify the above-mentioned effect, the applicant prepared 100 folded box-forming pieces 10 for each of sample No. 1, whose blank sheet had a thickness of 0.5 mm, sample No. 2, whose blank sheet had a thickness of 1.0 mm, and sample No. 3, whose blank sheet had a thickness of 1.5 mm, and visually verified the number of defects. As a result, the number of defects was sufficiently low, 0 for sample No. 1 and 2 for sample No. 2, whereas it suddenly increased to 10 for sample No. 3. From these results, it can be seen that the above-mentioned defects can be effectively suppressed by setting the thickness of the blank sheet to 0.7 mm or less, more preferably 0.5 mm or less.

[0046] Moreover, the larger the area of ​​the connecting pieces 224, 244 (excluding the bulging parts 224a, 244a), the smaller the effect of providing the bulging parts 224a, 244a. Therefore, the present invention is suitable for a small-sized packaging box 1. Specifically, the width W (see FIG. 6) of the side panels 23, 25 is preferably 40.0 mm or less, and more preferably 30.0 mm or less. In a packaging box 1 of such a size, it is difficult to secure a sufficient area for the connecting pieces 224, 244, and the applied glue B is likely to overflow from the connecting pieces 224, 244, resulting in a decrease in yield. Also, in order to prevent a decrease in yield, there are likely to be cases where the amount of glue B to be applied must be reduced. Therefore, the effect of providing the bulging parts 224a, 244a becomes significant.

[0047] Next, as shown in FIG. 21, in a factory where the contents are stored and packaged, the folding lines 31, 32, 33, and 34 are folded at 90° each, and the back panel 22 and the front panel 24, and the side panel 23 and the side panel 25 are opposed to each other to form the rectangular cylindrical body 11. At this time, as shown in FIG. 22, the flap 223, the connecting piece 224, the flap 233, the flap 243, the connecting piece 244, and the flap 253, which are folded so as to overlap each other in the folded state, are unfolded into a flat plate shape to form the bottom lid. In addition, the locking notches 223c and 243c formed in the flaps 223 and 243 engage with each other to maintain the bottom lid in a flat plate shape. With this configuration, the bottom lid is formed at the same time as the cylindrical body 11 is formed from the folded state, making it easy to assemble the packaging box 1.

[0048] Next, although not shown, after the contents are placed in the packaging box 1 from the upper opening of the cylindrical body 11, the flaps 231, 251 are folded 90° along the fold lines 53, 55, and further the top cover plate 241 is folded 90° along the fold line 541, and the insertion piece 242 is folded 90° along the fold line 542 and inserted into the back side of the back plate 22. As a result, the top opening of the cylindrical body 11 is closed by the top cover plate 241, and the placement of the contents is completed.

[0049] The packaging box 1 of this embodiment has been described above. As described above, such a packaging box 1 has a cylindrical body 11 having a back panel 22 as a first side panel, a side panel 23 as a second side panel, a front panel 24 as a third side panel, and a side panel 25 as a fourth side panel, which are connected in a rectangular cylindrical shape, a flap 223 as a first flap, a flap 233 as a second flap, a flap 243 as a third flap, and a flap 253 as a fourth flap, which are extended from one end of the back panel 22, the side panel 23, the front panel 24, and the side panel 25, a connecting piece 224 as a first connecting piece that extends from the flap 223 to the flap 233 side via a fold line 622 as a first fold line and has a back surface joined to the surface of the flap 233, and a connecting piece 244 as a second connecting piece that extends from the flap 243 to the flap 253 side via a fold line 642 as a second fold line and has a back surface joined to the surface of the flap 253. The connecting piece 224 has a bulging portion 224a as a first bulging portion bulging toward the flap 223 side from the folding line 622, and the connecting piece 244 has a bulging portion 244a as a second bulging portion bulging toward the flap 243 side from the folding line 642. With this configuration, since the connecting piece 224 has the bulging portion 224a, the area of ​​the connecting piece 224 can be increased accordingly. Therefore, the amount of glue B applied to the connecting piece 224 can be increased, and the adhesion strength with the flap 233 can be increased. In addition, the glue B is less likely to protrude from the connecting piece 224, and the connecting piece 224 can be prevented from sticking to the flap 223 or the back panel 22 that is folded under it. The same applies to the connecting piece 244. Therefore, the packaging box 1 has high joint strength and is less likely to have manufacturing defects.

[0050] As described above, in the folded state, the back panel 22, the flap 223, the connecting piece 224, the flap 233 and the side panel 23 are folded over, and the front panel 24, the flap 243, the connecting piece 244, the flap 253 and the side panel 25 are folded over. With this configuration, in the folded state, the parts extending from the lower end of the cylindrical body 11, that is, the flap 223, the connecting piece 224, the flap 233, the flap 243, the connecting piece 244 and the flap 253, are hidden within the cylindrical body 11. This results in a compact folded state.

[0051] As described above, the boundary between the flap 223 and the connecting piece 224 has the notch 225 as the first notch that forms the outline of the bulge 224a, and the bulge 224a appears when the connecting piece 224 is folded relative to the flap 223 at the fold line 622. Similarly, the boundary between the flap 243 and the connecting piece 244 has the notch 245 as the second notch that forms the outline of the bulge 244a, and the bulge 244a appears when the connecting piece 244 is folded relative to the flap 243 at the fold line 642. With this configuration, the bulges 224a and 244a can be easily formed.

[0052] As described above, the bulges 224a, 244a are curved in an arc shape, which makes the bulges 224a, 244a less likely to bend and makes it easier for the bulges 224a, 244a to rise when the connecting pieces 224, 244 are folded at the fold lines 622, 642 relative to the flaps 223, 243.

[0053] Although the packaging box of the present invention has been described above based on the illustrated embodiment, the present invention is not limited to the above embodiment. For example, the size, material, shape of each member, etc. of the packaging box can be changed as appropriate. In addition, in the above embodiment, each part is joined by gluing, but the joining method is not particularly limited. In addition, the packaging box may be formed by bonding multiple blank sheets together.

[0054] In addition, in the first embodiment described above, the first side panel is the back panel 22 and the third side panel is the front panel 24, but the orientation of the packaging box 1, i.e., which panel constitutes the front panel and which panel constitutes the back panel, is not particularly limited. [Explanation of symbols]

[0055] 1...packaging box, 10...box body forming piece, 11...tubular body, 21...glue piece, 22...back panel, 223...flap, 223a...hypotenuse, 223b...hypotenuse, 223c...locking notch, 224...connecting piece, 224a...bulge, 225...notch, 226...notch, 227...notch, 228...notch, 229...notch, 23...side panel, 231...flap, 233...flap, 24...front panel, 241...top cover panel, 242...insertion piece, 243...flap, 243a...hypotenuse, 243b...hypotenuse, 243c...locking notch, 244...connecting piece, 244a...bulge, 245...notch, 246...notch, 25...side panel, 251...flap, 253...flap, 31...fold line, 32...fold line, 33...fold line, 34...fold line, 53...fold line, 541...fold line, 542...fold line, 55...fold line, 621...fold line, 622...fold line, 63...fold line, 641...fold line, 642...fold line, 65...fold line, 91...side wall, 92...front wall, 93...side wall, 94...rear wall, 95...connecting piece, 911...second bottom wall component piece, 921...first bottom wall component piece, 922...connecting piece, 931...second bottom wall component piece, 941...first bottom wall component piece, 942...connecting piece, a...fold, b...fold, c...fold, B...glue

Claims

1. a cylindrical body including a first side plate, a second side plate, a third side plate, and a fourth side plate arranged in a rectangular cylindrical shape; a first flap, a second flap, a third flap and a fourth flap extending from one end of the first side panel, the second side panel, the third side panel and the fourth side panel; A first connecting piece extending from the first flap to the second flap side via a first fold line and having a back surface joined to a front surface of the second flap; A second connecting piece is provided extending from the third flap to the fourth flap side via the second fold line, and a back surface of the second connecting piece is joined to a front surface of the fourth flap, The first connecting piece has a first bulging portion bulging toward the first flap side from the first fold line, The second connecting piece has a second bulging portion that bulges toward the third flap side relative to the second fold line.

2. In the folded state, the first side panel, the first flap, the first connecting piece, the second flap and the second side panel are folded over each other, 2. The packaging box according to claim 1, wherein the third side panel, the third flap, the second connecting piece, the fourth flap and the fourth side panel are folded over each other.

3. A first cut is formed at the boundary between the first flap and the first connecting piece to form a contour of the first bulge, and the first bulge appears by folding the first connecting piece relative to the first flap at the first fold line, 2. The packaging box according to claim 1, wherein a second notch that defines the outline of the second bulge is formed at the boundary between the third flap and the second connecting piece, and the second bulge appears by folding the second connecting piece relative to the third flap at the second fold line.

4. The packaging box according to claim 1 , wherein the first bulge and the second bulge are each curved in an arc shape.

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