Packing box

Abstract

To provide a packing box with a trunk part which is clearly broken along a ridge line.SOLUTION: There is provided a packing box 1 comprising: a bottomed square-cylindrical trunk part 2 formed by continuously providing a plurality of side plates 21, 22 via a trunk part folding line a; and lid flaps 31, 32 continuously provided at upper end edges of the side plates 21, 22 via flap folding lines b, d, respectively. A breakable part 5 formed by arranging at least one unit cut 51 to the trunk part folding line a is provided at the trunk part 2. The at least one unit cut 51 includes: a vertical cut line 52 extending along the trunk part folding line a; two auxiliary cut lines 53 extending upward from positions spaced apart at a predetermined interval downward from a lower end of the vertical cut line 52, while separating from each other; and a swingable part 54 as an area sandwiched by the two auxiliary cut lines 53.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a packaging box with a changeable internal volume. [Background technology]

[0002] Packaging boxes with variable internal volume have been known for some time (see, for example, Patent Document 1). Conventional packaging boxes are so-called A-type packaging boxes, and have perforations along a vertical ridge from the top to the middle. With this packaging box, the body can be torn along the perforations by pulling the short side backward. Then, the short side is folded horizontally toward the inside of the packaging box so as to connect the bottom ends of the torn perforations, and then the long side is folded so as to connect the bottom ends thereof and overlap with the outer surfaces of the end side, whereby the box can be sealed in a second state in which the overall height is lowered and the internal volume is reduced compared to the initial first state.

[0003] In this way, when a short side of a conventional packaging box is pulled backward, both long sides try to support the short side against this, so that the box can be neatly torn along the ridge of the perforation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2002-104384 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the short side that is pulled backward is ultimately folded back toward the inside of the packaging box, so it is preferable to push it inward and fold it while breaking the perforation, rather than pulling it backward and then folding it inward, as this would reduce the number of steps.In particular, when sealing is automated using a device, the process of pulling it backward and then folding it inward increases the number of displacement directions of the device, making the structure complicated.

[0006] However, with conventional packaging boxes, when the short sides are pushed inward, the horizontal middle parts of both long sides bulge outward, absorbing the external force pushing against the short sides, making it difficult to break the perforations.

[0007] Furthermore, when the short side surface is pressed inward, the linear unit cuts that make up the perforations are opened laterally and deformed from above into a V-shape. Then, the uncut portion between the unit cut and the next unit cut is broken diagonally, biased from the ridge line toward the short side surface.

[0008] As a result, in conventional packaging boxes, when the short sides are pushed inward, concave break marks (jagged portions) are generated on the side edges of the short sides, and convex break marks (jagged portions) are generated on the side edges of the long sides. When such break marks are generated, when the flaps are folded again, the edges where the flaps are overlapped become uneven due to the break marks, which causes the next problem of making it difficult to seal the box. SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a packaging box in which the body portion is neatly broken along the ridge line when a part of the body portion is pushed inward. [Means for solving the problem]

[0009] The packaging box of the present invention comprises a bottomed, rectangular tubular body formed by connecting a plurality of side panels via a body crease line, and lid flaps each connected to the upper edges of the side panels via a flap crease line, wherein the body has a breakable portion formed by arranging one or more unit cuts along the body crease line from the upper end to the middle portion of the body crease line, the unit cuts having a vertical cut line extending along the body crease line, two auxiliary cut lines extending upward while being spaced apart from each other and provided on each of a pair of side panels sandwiching the body crease line from a position spaced a predetermined distance downward from the lower end of the vertical cut line, and a swingable portion which is an area sandwiched between the two auxiliary cut lines (hereinafter referred to as the "first packaging box of the present invention").

[0010] In the first packaging box of the present invention, a breakable portion is provided in the body portion by arranging one or more unit cuts along the body fold line from the upper end to the middle of the body fold line, so that by pushing one side panel inward, the body portion can be broken along the body fold line (coincident with the ridge line).

[0011] Next, since this unit cut has a vertical cut line that extends along the fold line of the body, and a swingable portion which is an area surrounded by two auxiliary cut lines, in order to break the body cleanly along the body fold line (which coincides with the ridge line), it is necessary to break the swingable portion between the upper vertical cut line and the lower vertical cut line along the body fold line.

[0012] However, in the packaging box of the first invention, when one side panel is pushed inward, the packaging box opens in a V shape starting from the vertical cut line at the top, similarly to conventional packaging boxes.

[0013] At this time, one side panel and the other adjacent side panel are divided into left and right by multiple vertical cut lines, and as a result, they are connected via the swingable part between them. Therefore, when one side panel is pushed inward, the part of the swingable part that is not separated from the side panel (near the two imaginary lines connecting the lower end of the uppermost vertical cut line and the upper ends of the two auxiliary cut lines) is pulled by the one side panel and is pushed slightly toward the inside of the packaging box, while the part of the swingable part that is separated from the side panel (around the auxiliary cut lines) is relatively curled up toward the outside of the packaging box and comes out of the side panel.

[0014] When the oscillating portion is further pulled by one of the side panels pushed inward, the vicinity of the imaginary line connecting the upper end of the auxiliary cutting line and the lower end of the vertical cutting line of one of the side panels is crushed, and the vicinity of the imaginary line connecting the upper end of the auxiliary cutting line and the lower end of the adjacent vertical cutting line of the other side panel is stretched, resulting in the lower end of the oscillating portion swinging closer to the one of the side panels.

[0015] In other words, the first packaging box of the present invention is broken diagonally near one of the pressed-in side panels rather than along the body crease line (ridge line) like conventional packaging boxes; however, when attempting to break the uncut portion (swingable portion) between the bottom end of the top vertical cut line and the top end of the next vertical cut line, for example, the swingable portion is positioned so as to swing diagonally, and as a result, the swingable portion can be broken approximately along the center (body crease line).

[0016] Therefore, according to the packaging box of the first aspect of the present invention, when one side plate is pushed inward, the body can be neatly torn along the body fold line (ridge line).

[0017] In the packaging box of the first invention, the auxiliary cut line preferably extends while being curved or bent downward in a convex shape (hereinafter, referred to as "the packaging box of the second invention").

[0018] In the packaging box of the second aspect of the present invention, the auxiliary cut line extends downward in a convex curve or bend. In other words, the pivotable part is configured to have a shape that bulges downward and outward, so that when one side plate is pushed inward, the part of the pivotable part that is separated from the side plate (the periphery of the auxiliary cut line) is likely to come out of the side plate.

[0019] Therefore, according to the packaging box of the second aspect of the present invention, the swingable portion can be more reliably removed from the side plate, and therefore it is easy to swing it and dispose it at an angle.

[0020] Therefore, according to the packaging box of the second invention, when one side plate is pushed inward, the body can be neatly broken along the body fold line (ridge line).

[0021] In addition, in the packaging boxes of the first and second aspects of the present invention, it is preferable that the side panels have auxiliary fold lines that connect the lower ends of the breakable portions provided on both side edges and extend parallel to the flap fold lines (hereinafter referred to as the "packaging box of the third aspect of the present invention").

[0022] In the third packaging box of the present invention, when one side panel is pushed inward, the auxiliary fold line can be used as a rotation axis, thereby preventing the side panel from twisting when pushed inward, which would cause a difference in the breaking of the two breakable portions formed on both side edges of the side panel on the left and right sides.

[0023] Therefore, according to the packaging box of the third aspect of the present invention, when one side plate is pushed inward, the body can be neatly torn along the body fold line (ridge line). [Brief description of the drawings]

[0024] [Figure 1] 1 is a perspective view showing an external configuration of a packaging box according to an embodiment of the present invention when sealed in a first state. [Diagram 2] FIG. 2 is a development view of the blank plate of the packaging box of FIG. 1; [Diagram 3] FIG. 2 is a perspective view of the bottom closure part of the packaging box of FIG. 1 in an assembled state; [Figure 4] 4A is an explanatory diagram showing the breaking process of the breakable portions of the packaging box in FIG. 1, where FIG. 4A is an oblique view showing the state before breaking begins, FIG. 4B is an oblique view showing the state in which the upper unit cut has been deformed, FIG. 4C is an oblique view showing the state in which the upper unit cut has been broken, FIG. 4D is an oblique view showing the state in which the central unit cut has been deformed, FIG. 4E is an oblique view showing the state in which the central unit cut has been broken, FIG. 4F is an oblique view showing the state in which the lower unit cut has been deformed, and FIG. 4G is an oblique view showing the state in which all breakable portions have been broken. [Diagram 5] 2 is a perspective view showing a state in which the front side panel of the packaging box in FIG. 1 is broken and folded along a breakable portion. [Figure 6] 2 is a perspective view showing the external configuration when the packaging box of FIG. 1 is sealed in a second state. FIG. [Figure 7] FIG. 11 is a development view of a blank plate of another embodiment of the packaging box of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] [Composition of Packaging Box 1] A packaging box 1 according to one embodiment of the present invention (hereinafter simply referred to as "first embodiment") will be described below with reference to the drawings. As shown in Fig. 1, the packaging box 1 of the first embodiment is a so-called type A corrugated cardboard box whose exterior is formed in a rectangular parallelepiped shape. The packaging box 1 has a rectangular tubular body 2 extending in the vertical direction, an upper closing part 3 that closes the upper open end of the body 2, and a closing part 4 that closes the lower open end of the body 2.

[0026] The body 2 is composed of a pair of short sides 21 and a pair of long sides 22. The short sides 21 and the long sides 22 are each connected via a body fold line a. The pair of short sides 21 face each other in the front-to-back direction, and the pair of long sides 22 face each other in the left-to-right direction. Both the short sides 21 and the long sides 22 correspond to the "side panels" in the present invention.

[0027] The body 2 has breakable portions 5 along the body fold lines a from the upper end to the middle of each body fold line a. In addition, auxiliary fold lines f are formed on each of the short side surface 21 and the long side surface 22 so as to connect the lower ends of the breakable portions 5.

[0028] The upper blocking part 3 is composed of a pair of inner flaps 31 and a pair of outer flaps 32. The inner flaps 31 and the outer flaps 32 correspond to the "lid flaps" in the present invention. The lower blocking part 4 is composed of a pair of inner flaps 41 and a pair of outer flaps 42.

[0029] [Composition of 1x corrugated cardboard] The packaging box 1 is assembled by punching out a roughly rectangular corrugated cardboard 1x shown in Fig. 2 from a base paper and then folding the corrugated cardboard 1x. The configuration of the corrugated cardboard 1x will be described below with reference to Fig. 2. Note that the surface of each element of the corrugated cardboard 1x in Fig. 2 is the part that will become the inner surface of the packaging box 1 when the packaging box 1 is assembled.

[0030] First, the outline of the configuration of the corrugated paperboard 1x will be described.

[0031] 2, the corrugated paperboard 1x is connected from the left side with a short side 21, a long side 22, a short side 21, a long side 22, and an adhesive strip 23, each connected via a body fold line a. The short side 21 and the long side 22 are both formed in a substantially rectangular shape, and have the same length in the up-down direction, while the length in the left-right direction of the long side 22 is set to be longer than that of the short side 21.

[0032] An upper inner flap 31 is connected to the upper end of the short side surface 21 via an upper inner flap fold line b. A lower inner flap 41 is connected to the lower end of the short side surface 21 via a lower inner flap fold line c. The upper inner flap 31 and the lower inner flap 41 are both of the same rectangular shape. The combined length from the base end to the tip end of the pair of upper inner flaps 31 (lower inner flaps 41) is set to be shorter than the left-right length of the long side surface 22.

[0033] An upper outer flap 32 is connected to the upper end of the long side surface 22 via an upper outer flap fold line d. A lower outer flap 42 is connected to the lower end of the long side surface 22 via a lower outer flap fold line e. The upper outer flap 32 and the lower outer flap 42 are both of the same rectangular shape. The combined length from the base end to the tip end of the pair of upper outer flaps 32 (lower outer flaps 42) is set to be approximately the same as the left-right length of the short side surface 21. The upper inner flap fold line b and the upper outer flap fold line d correspond to the "flap fold line" in this invention.

[0034] An auxiliary fold line f is formed on the short side 21, the long side 22, the short side 21, the long side 22, and the adhesive strip 23, from the left edge of the left short side 21 to the right edge of the adhesive strip 23. The auxiliary fold line f is provided parallel to the upper inner flap fold line b and the upper outer flap fold line d. The auxiliary fold line f is provided perpendicular to the body fold line a.

[0035] The length from the auxiliary fold line f to the tip of the inner flap 31 is set to be shorter than the left-right length of the long side surface 22. In addition, the length from the auxiliary fold line f to the tip of the upper outer flap 32 is set to be shorter than the left-right length of the short side surface 21.

[0036] Next, the configuration of the breakable portion 5 of the corrugated paperboard 1x will be described.

[0037] The breakable portion 5 is provided along the trunk fold line a from the upper end to the middle portion (approximately 30% from the upper end) of the trunk fold line a. More specifically, the breakable portion 5 is formed by arranging three sets of unit slits 51 in succession. Each of the unit slits 51 in the first embodiment is formed in a substantially anchor shape.

[0038] The unit cut line 51 has a vertical cut line 52 extending along the body fold line a, a pair of auxiliary cut lines 53, and a swingable portion 54 which is an area sandwiched between the pair of auxiliary cut lines 53.

[0039] The breakable portion 5 of the first embodiment has four vertical cut lines 52 that extend discontinuously along the trunk fold line a. Of these, the top three vertical cut lines 52 are provided as part of the unit cuts 51, and the bottom vertical cut line 52 is an additional feature provided separately from the unit cuts 51.

[0040] The pair of auxiliary cutting lines 53 extend downward from the lower end of the vertical cutting line 52 at a predetermined distance toward the short side surface 21 and the long side surface 22 that sandwich the body fold line a. The pair of auxiliary cutting lines 53 extend upward while being spaced apart from each other. Each auxiliary cutting line 53 extends downward in a convex curve. As a result, the pair of auxiliary cutting lines 53 are formed into a U-shape as a whole.

[0041] The oscillating portion 54 is a region sandwiched between a pair of auxiliary cutting lines 53, and more specifically, is a semi-elliptical region surrounded by a pair of auxiliary cutting lines 53 and a pair of imaginary lines connecting the upper ends of each auxiliary cutting line 53 and the lower ends of the vertical cutting lines 52.

[0042] [Assembly of packaging box 1] Next, a process for assembling the packaging box 1 shown in Fig. 1 from the corrugated paperboard 1x shown in Fig. 2 will be described. The packaging box shown in Fig. 1 is a normal form of a so-called A-type packaging box, and this will be defined as a first state for the description.

[0043] First, the worker folds short side 21, long side 22, short side 21, long side 22, and adhesive piece 23 at right angles along the body fold line a, and fixes the inner surface of short side 21 (the short side 21 on the left in Figure 2) to the outer surface of adhesive piece 23 via adhesive.

[0044] Next, the pair of lower inner flaps 41 are each folded along the lower inner flap crease line c toward the inside of the packaging box 1 so as to be perpendicular to the short side surface 21. Then, the pair of lower outer flaps 42 are each folded along the lower outer flap crease line e so as to be superimposed on the outer surface of the lower inner flap 41. As a result, the leading edges of the pair of lower outer flaps 42 are butted against each other, and adhesive tape is applied along both leading edges.

[0045] As a result, as shown in Figure 3, the lower closing section 4 is assembled using a pair of lower inner flaps 41 and a pair of lower outer flaps 42, thereby closing the lower open end of the body section 2 and allowing products to be stored inside.

[0046] Furthermore, the pair of upper inner flaps 31 are each folded along the upper inner flap crease line b toward the inside of the packaging box 1 so as to be perpendicular to the short side surface 21. Then, the upper outer flaps 32 are each folded along the upper outer flap crease line d so as to be superimposed on the outer surfaces of the upper inner flaps 31.

[0047] As a result, the leading edges of the pair of upper outer flaps 32 are butted against each other, and adhesive tape is applied along both leading edges.

[0048] As described above, the upper closing portion 3 is assembled by the pair of upper inner flaps 31 and the pair of upper outer flaps 32, thereby closing the upper open end of the body portion 2 and sealing the product in the packaging box 1.

[0049] [Breakage of breakable portion 5] Next, with reference to Figs. 3 to 6, a process of sealing the packaging box 1 of the first embodiment in a second state in which the overall height is lowered and the internal volume is reduced compared to the first state will be described.

[0050] First, as shown in Fig. 3, an operator pushes the upper end of the front short side surface 21 of the packaging box 1 with the lower closing portion 4 assembled inward (toward the rear) of the packaging box, and the breakable portion 5 is broken as shown in Fig. 5. Here, the details of breaking the breakable portion 5 will be explained with reference to Fig. 4. Note that the upper inner flap 31 is omitted in Fig. 4 for ease of understanding.

[0051] When the short side surface 21 is pressed inwardly into the packaging box 1, the vertical cutting line 52 constituting the topmost unit cut 51 opens in a V shape, as shown in FIG. 4B.

[0052] At this time, the short side surface 21 and the long side surface 22 (see Figs. 4D to 4G) connected to the left side are divided into left and right parts by four vertical cutting lines 52, and as a result, are connected via the swingable part 54 between them. More specifically, the periphery of the swingable part 54 is also divided from the short side surface 21 and the long side surface 22 by a pair of auxiliary cutting lines 53. Therefore, the short side surface 21 and the long side surface 22 are connected near a pair of imaginary lines connecting the upper ends of the auxiliary cutting lines 53 and the lower ends of the vertical cutting lines 52 of the swingable part 54, i.e., via the upper part of the swingable part 54.

[0053] Therefore, when the short side surface 21 is pushed inwardly into the packaging box 1 (toward the rear in FIG. 4), the upper part of the swingable part 54 constituting the topmost unit cut 51 is pulled by the short side surface 21 and pushed slightly inwardly into the packaging box 1. In comparison, the part of the swingable part 54 that is separated from the side panel (around the auxiliary cut line 53), i.e., the lower part of the swingable part 54, is rolled up toward the outside of the packaging box 1 and comes out from the short side surface 21 and the long side surface 22.

[0054] Furthermore, as shown in FIG. 4B, as the oscillating part 54 is pulled by the short side 21, the upper part of the oscillating part 54 on the short side 21 side is slightly crushed and the upper part of the oscillating part 54 on the long side 22 side is stretched, and as a result, the lower part of the oscillating part 54 oscillates closer to the short side 21.

[0055] When the short side surface 21 is further pressed inward, the top vertical cut line 52 opens further into a V shape, as shown in Fig. 4C, and the swingable portion 54 is torn in half. In other words, the packaging box 1 of the present invention is torn obliquely not along the ridge of the body portion 2 as in the case of conventional packaging boxes, but along the pressed short side surface 21, but the swingable portion 54 can be swung in advance and positioned so that it follows the diagonal breaking direction. As a result, the swingable portion 54 is torn approximately along the center (near where the body portion fold line a was originally formed).

[0056] Next, when the short side surface 21 is further pressed inward, the vertical cutting line 52 constituting the central unit cut 51 opens in a V shape, as shown in FIG. 4D.

[0057] Then, as the short side 21 is pushed inward into the packaging box 1, the upper part of the oscillating portion 54 that constitutes the second-highest unit cut 51 is pulled by the short side 21 and is slightly pushed inward into the packaging box 1, while the lower part of the oscillating portion 54 is curled up toward the outside of the packaging box 1, coming out from the short side 21 and the long side 22, and oscillating toward the short side 21.

[0058] When the short side surface 21 is further pressed inward, the second vertical cut line 52 from the top opens further into a V shape, as shown in FIG. 4E, and the swingable portion 54 is cut.

[0059] Furthermore, by repeating this process, as shown in Figures 4F and 4G, the oscillating portion 54 that constitutes the lowest unit cut 51 is cut, the lowest vertical cut line 52 is opened in a V shape, and the breakable portion 5 is broken.

[0060] In addition, Figures 4A to 4G have described how the breakable portion 5 on the left edge of the short side 21 is broken, but at the same time, the breakable portion 5 on the right side is also broken, so the short side 21 is mountain-folded along the auxiliary fold line f, and the short side 21 and the upper inner flap 31 connected to it are folded parallel to the lower closing portion 4 toward the inside of the packaging box 1.

[0061] [Sealing in the second state] Next, the upper end of the rear short side surface 21 of the packaging box 1 is pushed inward (toward the front) of the packaging box by an operator, and the breakable portions 5 on both the left and right sides of the rear short side surface 21 are broken. Then, the rear short side surface 21 of the packaging box 1 is mountain-folded along the auxiliary fold line f, the short side surface 21 and the upper inner flap 31 connected thereto are folded inward of the packaging box 1 parallel to the lower closing portion 4, and the upper inner flap 31 connected to the rear short side surface 21 is overlapped on the outer surface of the upper inner flap 31 connected to the front short side surface 21.

[0062] Next, the long side 22 on the right side of the packaging box 1 is folded along the auxiliary fold line f, and the long side 22 and the upper outer flap 32 connected to it are folded parallel to the lower closing portion 4 toward the inside of the packaging box 1 and overlapped on the outer surface of the short side 21 and the upper inner flap 31.

[0063] Next, as shown in Figure 6, the left long side 22 of the packaging box 1 is folded along the auxiliary fold line f, and the long side 22 and the upper outer flap 32 connected to it are folded inwardly of the packaging box 1 parallel to the lower closure portion 4 and overlapped on the outer surface of the right long side 22 and the upper outer flap 32 connected to it.

[0064] Finally, adhesive tape is applied along the leading edge of the upper outer flap 32 connected to the left long side surface 22.

[0065] As a result of the above, the upper open end of the body 2 is closed by the upper parts of a pair of short sides 21, the upper parts of a pair of long sides 22, a pair of upper inner flaps 31 and a pair of upper outer flaps 32, and the product is sealed in a second state in which the overall height is lower and the internal volume is reduced compared to the first state in Figure 1.

[0066] [Effects of packaging box 1] Next, the effects of the packaging box 1 according to the first embodiment will be described.

[0067] As described above, depending on the height of the product, the packaging box 1 of the first embodiment can seal the product in the normal first state shown in FIG. 1, and also in a second state in which the overall height is lower than in the first state and the internal volume is reduced, as shown in FIG. 6.

[0068] The packaging box 1 according to the first embodiment is torn obliquely not along the ridge of the body 2 but along the pressed short side surface 21, as in the case of conventional packaging boxes, but the swingable part 54 can be swung in advance to be positioned along the oblique breaking direction. As a result, the swingable part 54 can be broken approximately along the center (near where the body fold line a was originally formed).

[0069] Therefore, according to the packaging box 1, the body 2 can be neatly torn along the body crease line a. In other words, according to the packaging box 1, concave torn marks (jagged portions) are unlikely to appear on the side edges of the short side faces 21, and convex torn marks (jagged portions) are unlikely to appear on the side edges of the long side faces 22. And because such torn marks are unlikely to appear, when the upper inner flap 31 and the upper outer flap 32 are folded over in the second state, unevenness due to the torn marks is unlikely to occur, making sealing difficult.

[0070] In the packaging box 1 according to the first embodiment, each auxiliary cut line 53 extends downward in a convex curve, and as a result, the lower part of the swingable part 54 is formed into a U-shape as a whole. That is, the swingable part 54 in the first embodiment bulges while smoothly curving downward and outward, so that it is easy for the swingable part 54 to slip out from the short side surface 21 and the long side surface 22.

[0071] Therefore, according to the packaging box 1 according to the first embodiment, the swingable portion 54 can be easily arranged at an angle by being swung out of the short side surface 21 and the long side surface 22.

[0072] In the packaging box 1 of the first embodiment, an auxiliary fold line f is formed on the short side 21, connecting the lower ends of the breakable portions 5 provided on both side edges thereof and extending parallel to the upper inner flap fold line b, so that when the short side 21 is pushed inward into the packaging box 1, the auxiliary fold line f can be used as a rotation axis.

[0073] Therefore, when the packaging box 1 is pushed inward, it is possible to prevent twisting of the short side surface 21 and the difference in breaking between the left and right sides of the two breakable portions 5 formed on both side edges.

[0074] Therefore, according to the packaging box 1, the body portion 2 can be neatly torn along the body portion fold line a.

[0075] [Second embodiment] Next, a packaging box according to another embodiment of the present invention (hereinafter simply referred to as "second embodiment") will be described using a corrugated paperboard 10x with reference to Fig. 7. The second embodiment differs from the first embodiment only in the configuration of the breakable portion, so the breakable portion 6 of the second embodiment will be described below.

[0076] As shown in Fig. 7, the breakable portion 6 is provided along the body fold line a from the upper end to the middle portion (approximately 30% from the upper end) of the body fold line a. More specifically, the breakable portion 6 is formed by arranging three sets of unit slits 61 in succession. Each of the unit slits 61 in the second embodiment is formed in a shape similar to the Chinese character for "mountain."

[0077] The unit cut 61 has a vertical cut line 62 extending along the body fold line a, a pair of auxiliary cut lines 63 , and a swingable portion 64 which is an area sandwiched between the pair of auxiliary cut lines 63 .

[0078] The breakable portion 6 of the second embodiment has four vertical cut lines 62 that extend discontinuously along the trunk fold line a. Of these, the top three vertical cut lines 62 are provided as part of the unit cuts 61, and the bottom vertical cut line 62 is an additional feature provided separately from the unit cuts 61.

[0079] The pair of auxiliary cutting lines 63 extend downward from the lower end of the vertical cutting line 62 at a predetermined distance toward the short side surface 21 and the long side surface 22 that sandwich the body fold line a. The pair of auxiliary cutting lines 63 extend upward while being spaced apart from each other. Each auxiliary cutting line 63 is bent downward in a convex manner to extend in an L-shape. As a result, the pair of auxiliary cutting lines 63 are formed into an inverted U-shape as a whole.

[0080] The oscillating portion 64 is a region sandwiched between a pair of auxiliary cutting lines 63, and more specifically, is a rectangular region surrounded by a pair of auxiliary cutting lines 63 and a pair of imaginary lines connecting the upper ends of each auxiliary cutting line 63 and the lower ends of the vertical cutting lines 62.

[0081] The above-described breakable portion 6 provides the same effects as those of the breakable portion 5.

[0082] That is, in the packaging box according to the second embodiment, each auxiliary cut line 63 extends downwardly in a convex manner, and as a result, the lower part of the swingable part 64 is formed into an inverted U-shape as a whole. That is, since the swingable part 64 in the second embodiment bulges downward and outward, it is easy for it to slip out from the short side surface 21 and the long side surface 22.

[0083] Therefore, according to the breakable portion 6 in the second embodiment, the swingable portion 64 can be easily disposed at an angle by being swung out of the short side surface 21 and the long side surface 22.

[0084] [Variations] In the first and second embodiments (hereinafter simply referred to as the above embodiments), cardboard has been used as an example of the material, but the material may be cardboard or a thin synthetic resin plate as long as it can be folded and assembled and can be broken along the breakable line.

[0085] In the above embodiment, the body 2 is described as being rectangular tubular, but as long as the body has three or more side plates, it may be triangular, pentagonal, hexagonal, or other tubular.

[0086] In the above embodiment, the body 2 is configured with a pair of short side surfaces 21 and a pair of long side surfaces 22, but the side panels may have the same widthwise length and there may be no distinction between the short and long sides. Also, in the above embodiment, the short side surfaces 21 are pushed inwardly into the packaging box 1, but the long side surfaces 22 may be pushed in. However, the short side surfaces 21 are preferable because they are shorter in width and less likely to bend, making it easier to break the breakable portion 5.

[0087] In the above embodiment, an example was described in which the upper open end of the body 2 was closed with a pair of upper inner flaps 31 and a pair of upper outer flaps 32. However, in the present invention, a single flap connected to a specified side panel corresponding to the short side 21 or the long side 22 is sufficient, so the packaging box of the present invention may be a type B packaging box in which the upper open end of the body 2 is closed with this single flap.

[0088] In the above embodiment, an example has been described in which the lower open end of the body portion 2 is closed with a pair of lower inner flaps 41 and a pair of lower outer flaps 42. However, the configuration for closing the lower open end of the body portion 2 may be any, for example, a bottom lock or an American lock.

[0089] In the above embodiment, an example was described in which an auxiliary fold line f is formed on each of the short side 21 and the long side 22 to connect the lower ends of the breakable portions 5, but the auxiliary fold line f can be omitted.

[0090] In the above embodiment, an example was described in which one auxiliary fold line f was formed, but it is also possible to add one or more auxiliary fold lines f in the middle part of the breakable portion 5 to add a third state, a fourth state, etc. in which the overall height is greater than the first state and less than the second state, so as to configure the internal volume to be able to be changed in stages.

[0091] In the above embodiment, the breakable portion 5 is provided from the top end of the body fold line a to the middle part (about 30% from the top end), but the length of the breakable portions 5, 6 can be designed appropriately. Also, the number of unit cuts 51 is not limited to three, and multiple cuts can be provided depending on the length of the breakable portion 5, and conversely, if the length of the breakable portion 5 is short, only one cut can be provided.

[0092] In the above embodiment, the breakable portion 5 is provided by adding the vertical cut line 52 below the lowest unit cut 51, but additional cut lines can be added as appropriate above, below, to the left and right of the unit cut 51. In the present invention, the breakable portion 5 is provided from the upper end to the middle of the body fold line a in order to reduce the overall height and reduce the internal volume, but an additional cut line can be provided on the body fold line a to the lower end for use when disassembling the box, rather than as a breakable portion 5.

[0093] In the above embodiment, an example was described in which the lower end of the auxiliary cutting line 53 that constitutes the upper unit cut 51 is connected to the upper end of the vertical cutting line 52 that constitutes the lower unit cut 51, but as long as the unit cuts 51 can be broken continuously, they do not have to be connected. In the above embodiment, the two auxiliary cutting lines 53 are formed in a pair in a symmetrical shape in FIG. 2, but it is also possible to configure the left and right sides in different shapes.

[0094] In the above embodiment, an example was described in which a pair of auxiliary cutting lines 53 extend upward while gradually separating from each other, and a pair of auxiliary cutting lines 63 extend parallel to each other at their tips, but it is sufficient for the auxiliary cutting lines 53 (63) to extend upward while separating from each other and surround the lower end of the vertical cutting line 52, so there may be some points where they extend parallel to each other and close to each other.

[0095] In the above embodiment, an example was given of auxiliary cutting line 53 extending in a convex curve downward, and auxiliary cutting line 6 extending in a convex bent downward, but it is sufficient for a pair of auxiliary cutting lines 53 (63) to extend upward while being spaced apart from each other, so each auxiliary cutting line 53 (63) may extend in a convex curve or bend upward, or may be straight. In the above embodiment, an example was described in which three unit cuts of the same shape were provided as unit cuts 51, but as long as each unit cut has the above-mentioned vertical cut line, a pair of auxiliary cut lines, and a swingable portion, the three unit cuts may be configured to have different shapes.

[0096] In the above embodiment, the adhesive tape is used as a means for fixing the flap, but the fixing means may be an adhesive or a staple. [Explanation of symbols]

[0097] 1 packaging box 2. Torso 21 Short side (side plate) 22 Long side (side plate) 31 Upper inner flap (lid flap) 32 Upper outer flap (lid flap) 5 Breakable Part 51 Unit Break 52 Vertical line of sight 53 Auxiliary cut line 54 Swingable part a Body fold line b Upper inner flap fold line (flap fold line) d Upper outer flap fold line (flap fold line) f Auxiliary fold line

Claims

1. A packaging box having a bottomed rectangular tubular body formed by connecting a plurality of side panels via body fold lines, and lid flaps connected to the upper edges of the side panels via flap fold lines, The body portion is provided with a breakable portion formed by arranging one or more unit cuts along the body fold line from the upper end to the middle portion of the body fold line, The packaging box is characterized in that the unit cut has a vertical cut line extending along the body fold line, two auxiliary cut lines extending upward while being spaced apart from each other, the two auxiliary cut lines being provided on each of a pair of side panels that sandwich the body fold line from a position spaced a predetermined distance downward from the lower end of the vertical cut line, and a swingable portion which is an area sandwiched between the two auxiliary cut lines.

2. The packaging box according to claim 1, The packaging box is characterized in that the auxiliary cutting line extends downwardly while being curved or bent in a convex manner.

3. The packaging box according to claim 1 or 2, The packaging box is characterized in that an auxiliary fold line is formed on the side panels, connecting the lower ends of the breakable portions provided on both side edges of the side panels and extending parallel to the flap fold line.

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